Operation and Maintenance Manual for Hemavathy Dam State

Guidelines for Instrumentation of Large Dams September 2016

Operation and Maintenance Manual for Hemavathy Dam State of Karnataka

Doc. No. CDSO_O&M_KA06HH0117_HEMAVATHY_DAM

KAWRD_01_v1.0

June 2019

O&M Manual for Hemavathy Dam June 2019

Front Cover Photograph: Downstream view of Hemavathy Dam during flood releases. Rehabilitation works carried out under the Dam Rehabilitation & Improvement Project (DRIP).entailed single contract for works carried out to reduce seepage and leakage within the concrete / masonry structure by doing PICC pointing to the upstream face stone masonry joints of the dam body wall, reconstruction of upstream revet-ment of the embankment portion, rehabilitation of damaged surface of spillway glacis and flip bucket portion and providing shotcreting to the upstream surface of spillway piers to minimize the seepage.


Doc. No. CDSO_O&M_KA06HH0117_Hemavathy Dam_v1.0 Page iii

Operation and Maintenance Manual for Hemavathy Dam

Prepared by the Dam Safety Rehabilitation Directorate

with Assistance from

CAUVERY NEERAVARI

NIGAMALIMITED

(A Government of Karnataka Enterprises) State of Karnataka


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Team Involved in Preparing this O&M Manual

Sreenatha S V Assistant Executive Engineer, CNNL, Dam Sub Division, Hemava-

thy Project

Venkataravanappa C M Assistant Engineer, CNNL, Dam Sub Division, Hemavathy

Project (Draft Development)


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TABLE OF CONTENTS

LIST OF FIGURES ..................................................................................................................... X

CHAPTER 1. - GENERAL INFORMATION ................................................................................... 1

1.1 Introduction……………………………………………………………………………1

1.2 Purpose, Location &Description of Hemavathy Dam…………………………………1

1.3 Background Details of the Project……………………………………………………..2

1.3.1 Dam site Location:………………………………………………………….3

1.3.2 Hemavathy Reservoir Planning:…………………………………………...3

1.3.3 Main Design Features and Components of Hemavathy Dam:…………..7

1.4 Salient Features of Hemavathy Dam…………………………………………………...8

1.5 Assignment of Responsibility…………………………………………………………17

1.5.1 Roles and Responsibilities of the AEE and AE during Monsoon………19

1.5.2 Roles and Responsibilities of the SE and EE during Monsoon………...20

1.5.3 Roles and Responsibilities of the Chief Engineer during Monsoon……21

1.6 Collection & Reporting of Dam and Reservoir Data…………………………………22

1.7 Public and Project Staff - Health and Safety………………………………………….25

1.7.1 Restricted Areas……………………………………………………………25

1.7.2 Details of the Security arrangements at Hemavathy Dam Site.…………25

1.8 Staff Position, Communication & Warning System…………………………………...27

1.8.1 Schedule of General duties for Project Engineers…………………………..29

1.8.2 Electro-Mechanical Inspections / Checks .......................................... ..32

1.9 Distribution of Operation and Maintenance Manual…………………………………34

1.10 Supporting Documents & Reference Material…………………………………...35

CHAPTER 2. PROJECT OPERATION ............................................................................... …36

2.1 Basic Data ................................................................................................................................ 36

2.1.1 Area Capacity curves. ............................................................................. 36

2.1.2 Design Flood and Features Related to Safety ........................................ 43

2.2 Flood Management at Hemavathy Reservoir ..................................................................... 47

2.2.1 Gate Operations: ..................................................................................... 47

2.2.2 Rule Curve .............................................................................................. 50

2.2.3 Flood Peaks of different return Periods…………………………………….52

2.2.4 Recommended Gate Operation Procedures for Normal Flow Conditions53

2.2.5 Inflow Forecasting .................................................................................. 54

2.2.6 Methodology of Flood Regulation at Hemavathy ................................. 55

The Methodology is explained in section 2.2 above. ......................................... 55

2.2.6.1 Inflow Computation ............................................................................. 55


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2.2.6.2 Examples of Inflow Computation ...................................................... 56

2.2.6.3 Computation procedure for Required Radial Crest Gate Opening57

2.2.7 Summary of Flood Regulation Procedure. ............................................ 63

2.3 Operation of Radial Crest Gates of Hemavathy Dam ...................................................... 63

2.3.1 Brief Description. ................................................................................... 63

2.3.2 Radial Crest Gates – Technical Data ..................................................... 64

2.3.3 Salient Features....................................................................................... 65

2.3.4 Photographs of Electro-mechanical network of gates. .......................... 65

2.4 Operating Instructions ........................................................................................................... 70

2.4.3 Checklist Before Operation .................................................................... 71

2.4.4 Electrically operated Hoisting Arrangements for Radial Crest Gates ... 71

2.5 RESERVOIR LEVEL ........................................................................................................... 72

2.5.3 RIVER OUTLET WORKS: ................................................................ 72

2.6 DESCRIPTION ..................................................................................................................... 73

2.6.1.1 RIVER SLUICE GATES: ................................................................... 73

2.6.1.2 Head Regulator……………………………………………………..73

2.6.2 Operation: ................................................................................................... 74

2.6.2.1 General ................................................................................................... 74

2.6.2.2 Restrictions: .......................................................................................... 74

2.6.2.3 Mechanical: ........................................................................................... 74

2.6.3 References: .................................................................................................. 75

2.6.3.1 Drawings: .............................................................................................. 75

2.7 Access Roads ........................................................................................................................... 76

2.8 Record Keeping ...................................................................................................................... 76

CHAPTER 3 - PROJECT INSPECTIONS ..................................................................................... 77

3.1 Types of Inspections .............................................................................................................. 77

3.1.1 Comprehensive Evaluation Inspections................................................. 78

3.1.2 Scheduled Inspections ............................................................................ 78

3.1.3 Special (Unscheduled) Inspections ........................................................ 79

3.1.4 Informal Inspections .............................................................................. 80

3.1.5 Pre- and Post-Monsoon Checklist and Example of Report Proformas ...................... 80

CHAPTER 4 - PROJECT MAINTENANCE .................................................................................. 91

4.1 Maintenance Priorities ............................................................................................................ 91

4.1.1 Immediate Maintenance ........................................................................ 91

4.1.2 Preventive Maintenance ......................................................................... 92

4.1.2.1 Condition Based Maintenance ............................................................... 92


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4.1.2.2 Routine Maintenance ............................................................................. 93

4.2 Procedures for Routine Maintenance .................................................................................. 94

4.2.1 Earthwork ............................................................................................... 94

4.2.2 Masonry / Concrete Dams & Spillways ................................................ 100

4.2.3 River Sluices ........................................................................................... 100

4.2.4 Gates & Electro-mechanical Equipment .............................................. 101

4.2.5 Electrically operated fixed hoists .......................................................... 104

4.3 Maintenance of Electrical Components of fixed rope drum hoists…………………106

4.4 Surface Preparation and Painting of HM works……………………………………108

4.5 Electrical system…………………………………………………………………...113

4.6 Maintenance of Metal Gate Components…………………………………………..114

4.7 Access Roads ……………………………………...........................................................114

4.8 General Cleaning …………………………………………………………………..114

4.9 Materials and Establishment requirements during Monsoon Period………………...114

4.10 General List of Maintenance Roads………………………………………………114

4.11 Preparation of O & M Budget ……………………………………………………115

CHAPTER 5 - INSTRUMENTATION AND MONITORING .......................................................... 119

5.1 Dam Instrumentation: .............................................................................. ………………119

5.1.1 General Information .............................................................................. ….119

5.1.2 Instruments Embedded in the Hemavathy Earthen Dam........................ 119

5.1.3 Additional instruments planned to install under DRIP. .......................... 119

5.1.4 Seismological Observations ....................................................................... 120

5.1.5 Parameters Being Permanently monitored………………………………..120

5.1.6 Frequency of Monitoring …………………………………………………..121

CHAPTER 6 - PREVIOUS REHABILITATION EFFORTS ........................................................... 122

CHAPTER 7 - UPDATING THE MANUAL ................................................................................ 123

APPENDIX I – BASIC DRAWINGS OF HEMAVATHY DAM ....................................................... 124

APPENDIX II― KEY ELEMENTS OF THE EAP ....................................................................... 132

APPENDIX III ― MATERIAL REQUIRED FOR MAINTENANCE DURING MONSOON .............. 143

APPENDIX IV― SCHEDULED OR UNSCHEDULED DAM SAFETY INSPECTION FORM ............ 145

APPENDIX V - GLOSSARY ...................................................................................................... 172

List of Tables

Table 1 - The estimated yield & utilization details of the Hemavathy Project 2

Table 2 – Overall Responsibilities for Hemavathy Dam 18


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Table 3 – Roles & Responsibilities of AEE & AE 19

Table 4 – Roles & Responsibilities of SE & EE 20

Table 5 – Roles & Responsibilities of the Chief Engineer 21

Table 6–Example Proforma for recording Flow Data 24

Table 7 - Distribution of O&M Manual and Revisions 34

Table 8 - Elevation - Capacity Table for Hemavathy Reservoir 38

Table 9 - Details of Peak floods for different sub catchments 43

Table 10 - Details Showing the flood absorption capacity 48

Table 11 - Table showing the recorded inflow into the reservoir during monsoon period. 49

Table 12 - Rule curve table of Hemavathy Dam showing month and storage capacity 50

Table 13 - Rule curve table of Hemavathy Dam showing month and reservoir elevation. 51

Table 14 - Return Flow Peak Flows vs. Return Period Data 52

Table 15 - Details showing the monthly recommended water releases to the irrigation and drinking water supply. 53

Table 16 - Hemavathy reservoir project table of discharges over spillway v/s gate openings above gate seat. 57

Table 17 - Calibration chart for discharge through River Sluice gate of Hemavathy Dam. 74

Table 18 - Calibration chart for discharge through canal Sluice gates of Hemavathy Dam. 75

Table 19 - O&M BUDGET COSTS (ANNUAL) 116

Table 20 - Location and Extents of Structural Members 119

Table 21 - Embedded Instruments 119

Table 22 - Additional Instruments. 119

Table 23 - Frequency of Readings for Hemavathy Dam. 121

LIST OF FIGURES

Figure 1 Cauvery Basin Map ...................................................................................................................................... 5

Figure 2 Overhead Image of Hemavathy Dam ....................................................................................................... 6

Figure 3 Layout of Hemavathy Dam Premises ..................................................................................................... 26

Figure 4 Organization Chart..................................................................................................................................... 28

Figure 5 Area Capacity Curve .................................................................................................................................. 37

Figure 6 - Peak flood (PMF) Hydrograph .............................................................................................................. 46

Figure 7 - Catchment area map with sub catchments .......................................................................................... 47

Figure 8 - Rule curve of Hemavathy Dam ............................................................................................................. 51

Figure 9 - Rule curve of Hemavathy Dam ............................................................................................................. 52

Figure 10 - Peak Flows vs. Return Periods ............................................................................................................ 53


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Acronyms used in this publication are as follows:

BIS Bureau of Indian Standards

CDSO Central Dam Safety Organisation

CWC Central Water Commission

SDSO State Dam Safety Organisation

O&M Operation and Maintenance

DRIP Dam Rehabilitation and Improvement Project

DSRP Dam Safety Review Panel

EAP Emergency Action Plan

GPS Global Positioning System (uses GPRS for data transmission like browsing the web)

FRL Full Reservoir Level

MWL Maximum Water Level

MDDL Minimum Draw Down Level

DSL Dead Storage Level

SCADA Supervisory Control and Data Acquisition

EDA Energy Dissipation Arrangement

HM works

Hydro-Mechanical works

DG set Diesel Generator set

RMU Remote Monitoring Unit

PC Personal Computer

TMC Thousand-Million M3


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CHAPTER 1. - GENERAL INFORMATION

1.1 Introduction

This document represents a detailed Operation and Maintenance (O&M) Manual for Hemavathy

Dam, Karnataka, providing written descriptions of procedures for ensuring that the dam operates

safely and is kept in a good condition by periodic inspections, repairs, maintenance in a sustainable

manner. Timely maintenance is important for the continued safe functioning and productive use

of the dam and reservoir.

The Manual has been prepared primarily for the dam operation’s staff and their supervisors who

are assigned the responsibility for the physical operations and maintenance of the dam. It contains,

as a minimum, all information and instructions necessary for them to perform their allotted tasks

in a safe manner. In addition to instructions for dam operations staff, the Manual includes all

necessary instructions for other staff directly or indirectly involved in operating and maintaining

the dam.

It is essential that the Manual or a copy of the Manual along with supporting data including the

atlas of all drawings are available at site for ready reference.

1.2 Purpose, Location &Description of Hemavathy Dam

Hemavathy river is the main tributary of Cauvery river which is being an inter-state river. Water

utilization as of now is in accordance with the CWDT (Cauvery Water Disputes Tribunal) award

of 1991 based on the estimated 50% dependable yield with return flows. The water allocated to

Karnataka was 284.75 TMC. Out of this, an allocation made for Hemavathy Project is 1,236.86

MCM (43.68 TMC).

The Hemavathy Project has been taken up to provide irrigation facilities to the drought prone

areas of Hassan, Tumkur, Mandya and Mysore Districts. The Hemavathy project has been planned

to irrigated total area of 7,00,756 acres (or 2,83,586 hectares) out of which 6,55,000 acres (or

2,65,069 hectares) is by gravity irrigation, 35,750 acres (or 14,468 hectares) by lift irrigation on

canals & 10,000 acres (or 4,047 hectares) by lift irrigation on foreshore of reservoir.

The estimated yield & utilization details of the Hemavathy Project as per the project report is

shown in Table – 1 below.



Table 1 - The estimated yield & utilization details of the Hemavathy Project

50% Dependable

Yield at dam site

78.687 TMC FT. considering 69 years of inflow from 1916-17

to 1984-85.

Total utilisation a) 52.28 TMC–Utilisation by direct atchkat of 6.55 lakhs acres

by gravity irrigation under Hemavathy Project including res-

ervoir evaporation.

b) 8.14 TMC–Utilisation under upstream projects viz., Vote-

hole & Yagachi Projects.

c) 5.76 TMC–Assurance to 3 Anicut Channels downstream of

Hemavathy Reservoir.

d) 2.00 TMC– Drinking water needs of Tumkur Town, Hassan,

K.R.Pet, Arakalgud, Tiptur and NagamangalaTowns.

e) 1.87TMC- Utilisation under 4 Lift Irrigation Scheme namely,

Arkalgud L.I.S, Hallimysore L.I.S, L.I.Scheme at approach

of Bagur Navile Tunnel and L.I.Scheme at exit of Bagur-

Navile Tunnel.

f) 0.52 TMC-Lift Irrigation Schemes of Foreshore of Reser-

voir.

g) 6.804 TMC-Existing utilisation under Minor Irrigation Up-

stream of Hemavathy Reservoir.

h) 0.15 TMC-Utilisation contemplated under ongoing

M.I.schemes upstream of Hemavathy Reservoir.

i) 1.163 TMC-Releases from the Reservoir to Augment needs

of Kamasamudra Lift Irrigation Scheme and Huchhanakop-

palu Lift Irrigation Scheme contemplated lower down of

(downstream) reservoir.

Total 78.687 TMC or 2228.15 M Cum.

1.3 Background Details of the Project

The Hemavathy river is one of the main tributaries to Cauvery river and has its source in Ballara-

yanadurga of the western ghats in the Mudigere taluk of Chikkamagalore District, Karnataka state

and it flows in Hassan and Mandya District for a length of 192 KM (120 miles) before joining the

Cauvery river in the water spread of Krishnarajasagar in Mandya District.



The river had not been fully harnessed on the upstream of Krishnarajasagar for providing

Irrigation facilities to the area on either side of its banks. However, water is being drawn through

some old river anicut (Diversion Weirs) Channels, apart from its contribution to

Krishnarajasagar.

With a view to utilizing the waters entitled as per the agreement and also to provide facilities in the

arid areas of Holenarasipur, Hassan, Channarayapattna, Arakalgud, K R Pet & Pandavapura Ta-

luks, the dam was constructed across Hemavathy River near Gorur to restore and utilize the water

for irrigation. The project also contemplated to enlarge its scope at a later stage. In view of this

the irrigation facilities were extended to lands in the adjacent Cauvery valley at which ridge between

the Hemavathy & Cauvery rivers. Accordingly, the project was proposed to be implemented in II

stages as under.

STAGE – I

1. Dam and submergence.

2. Hemavathy Left Bank Canal.

3. Hemavathy Right Bank Canal.

4. Hemavathy Right Bank High Level Canal.

STAGE – II

1. Tumkur Branch

2. Nagamangala Branch

1.3.1 Dam site Location:

Hemavathy dam is situated at Latitude 12º 45’ 0” North and Longitude 76º03’0” East. The nearest

Railway station is Hassan on Mysore-Arsikere Railway line and is at a distance of 24 km on Hassan-

Arkalgud road. The Airports nearer to site are at Bangalore and Mangalore at a distance of 210 km

and 195 km respectively by Road. The nearest sea port is at Mangalore.

1.3.2 Hemavathy Reservoir Planning:

i). Catchment: The catchment area of the Hemavathy River at Hemavathy dam site is2810sq.-

km. (1084.947sq-miles). The head reaches of the catchment area lie in Western Ghats, where the

average rainfall is nearly 153.42cm per annum. The bulk of the rainfall occurs in the months of

June to September and the river will be in floods during these months when almost the entire yield

is received.



ii) Yields: The maximum and minimum annual virgin yields at Hemavathy dam site from derived

run off data for the years 1917 to 1985 are 4771 MCM (168.501 TMC) and 1245.929 MCM

(44TMC) respectively. The 50% dependable yield at this site is worked out to be 2228.14 MCM

(78.687 TMC).

iii) Storage: The dam is designed to pass a probable maximum flood of4020.95 cumec (1, 42,

000 cusecs).The gross storage capacity at FRL of 2922 ft is 1050.63 MCM (37.103 TMC) with a

live storage of 926.82 MCM (32.731 TMC) and a dead storage of 123.88 MCM (4.372 TMC) at

MDDL of 2862ft.The crest level of the spillway is at R.L 2892ft.

iv) Water Spread: The reservoir water spread submerges an area of 8502ha (21008 acres)

displacing a number of families of about 2283Nos.



Figure 1Cauvery Basin Map



Figure 2 Overhead Image of Hemavathy Dam



1.3.3 Main Design Features and Components of Hemavathy Dam:

i) Components: The dam consists of a spillway portion for a length of 94m in the centre of the

river gorge, with two non-overflow masonry dam sections on either side flanked by an earthen

dam on either side for a length of 1629m & 1680m in left side and right side, respectively. The

non-overflow masonry dam on the left side is of length 151-m and on the right side is121-m.

ii) Earthen Dam: The earthen dam has a maximum height of 58.52-m from the foundation

stripped level and consists of zonal sections with impermeable hearting zone and semi-permeable

casing zone on upstream and downstream of the hearting zone, and 3.05m height on the top. A

cut-off trench taken up to hard rock, filled with the impermeable soil is provided below the heart-

ing zone. The rock below the cut-off trench is curtain grouted. An inclined graded sand filter of

2.0-m and horizontal graded sand filter of 1.0-m are provided downstream of the hearting zone.

A 61-cm thick rip rap over a filter layer of 45-cm is provided on the upstream side of the earthen

embankment with concrete toe wall. Rock toes on downstream are provided with graded filters at

their base and embankment sides. Horizontal berms 3.0-m wide are provided on the downstream

slope of the embankment at a designed elevation of the earthen dam. Downstream slope of the

embankment is provided as 3H:1V&2H:1V, whereas for the upstream side slopes of 3H:1V&

3.5H:1Vare provided. The dam top width is 5.49-m.

iii) Masonry non-overflow section: This portion is constructed in un-coursed rubble stone ma-

sonry in cement mortar 1:4 for hearting. The upstream and downstream faces are provided with

67.5cm thick coursed stone masonry in cement mortar of 1:3 & 1:4 in upstream and downstream

respectively. A drainage gallery of size 1.52-m x 2.28-m is provided in the central masonry portion

for a distance of 354.6-m. Drain holes of 75-mm diameter at intervals of 6.0-m c/c are provided

in the gallery. A road way 5.49-m wide with parapets is provided at the dam top.

iv) Spillway Dam Section: The Spillway is of gravity

type which is constructed with stone masonry except for

the portion of the nappe on the downstream and the top

portion of the crest, where the construction is of cement

concrete. 6 Nos. of radial crest gates of size 10.66-m X

9.14-m are provided in the spillway portion which are de-

signed to dispose off the total flood discharge of

1,28,000 cusecs. The gate hoisting system is a rope-drum

type.

View of 40 Tonnecapacity moving GantryCrane



v) River Sluice Gates: Five (5) River Sluice Gates of size 2.44-m-wideby4.26-mhigh are provided

for Hemavathy Dam to operate when the water level recedes in the reservoir below the crest level

of 881.49m which operates electrically. For servicing of river sluice gates, a 40-T moving Gantry

crane has been provided with emergency gate. Periodical maintenance such as lubrication, filling

of gear oil, etc., are being done annually on a tender basis. Replacements of wire ropes, rubber

seals and painting of river sluice gates& emergency gates are being taken up whenever required on

tender basis.

vii) Irrigation Sluices: Hemavathy Dam is provided with 3 main canals out of which Hemavathy

Left Bank Canal and Right bank canals off taking from the dam having 5 Nos. & 4 Nos. of sluice

gates of size 2.44-m wide by 3.05-m height respectively, which operate electrically (rope – drum

type). For servicing of irrigation canal sluice gates, a 25-T moving Gantry crane has been provided

with an emergency gate& Hemavathy Right Bank High Level Canal off takes in the backwater

having a 2 Nos. sluice gates of size 1.52-m wide by 3.05-m high operated with electrical motors.

Periodical maintenance of these gates is taken up annually on tender basis which includes items

such as lubrication and filling of gear oil, Cardium compound, etc... Replacements of wire ropes,

rubber seals and painting of irrigation sluice gates are being taken up as required on tender basis.

1.4 Salient Features of Hemavathy Dam

I. GENERAL:

1. Name of the Project Hemavathy Reservoir Project across Hemavathy River near

Gorur village in Hassan Taluk.

2. Location Latitude12°- 45 '- 0 ''North.

Longitude76°- 03 '- 0 ''East.

3. Means of Access. The Dam is approachable by Hassan-Arakalgud Road at about

0.5 Kms from Hemavathy Bridge across that road.

II. GEOPHYSICAL:



1. Catchment area 2810 Sq. Km. (1085 Sq. miles)

2. Nature of Catchment The catchment is almost hilly and considered as “Good”

3. Weighted average

Rainfall in the catch-

ment area.

Maximum - 508 Cms. (200 '')

Minimum - 76.2 Cms. (30'')

Average - 153.42 Cms. (60.4'')

4. 50% Dependable

Yield at dam site

78.687 TMC FT. considering 69 years of inflow from 1916-17

to 1984-85.

5. Total utilization j) 52.28 TMC–Utilisation by direct atchkat of 6.55 lakhs acres

by flow irrigation under Hemavathy Project including reser-

voir evaporation.

k) 8.14 TMC–Utilisation under upstream projects viz., Vote-

hole & Yagachi Projects.

l) 5.76 TMC–Assurance to 3 Anecut Channels downstream of

Hemavathy Reservoir.

m) 2.00 TMC– Drinking water needs of Tumkur Town, Has-

san, K.R.Pet, Arakalgud, Tiptur and Nagamangala Towns.

n) 1.87 TMC- Utilisation under 4 Lift Irrigation Scheme

namely, Arkalgud L.I.S, Hallimysore L.I.S, L.I.Scheme at ap-

proach of Bagur-Navile Tunnel and L.I.Scheme at exit of

Bagur- Navile Tunnel.

o) 0.52 TMC-Lift Irrigation Schemes of Foreshore of Reser-

voir.

p) 6.804 TMC-Existing utilisation under Minor Irrigation Up-

stream of Hemavathy Reservoir.

q) 0.15 TMC-Utilisation contemplated under ongoing

M.I.schemes upstream of Hemavathy Reservoir.

r) 1.163 TMC-Releases from the Reservoir to Augment needs

of Kamasamudra Lift Irrigation Scheme and Huchhanakop-

palu Lift Irrigation Scheme contemplated lower down of

(downstream) reservoir.

Total 78.687 TMC or say 2228.15 M Cum.



III. PURPOSE: Irrigation.

IV.TECHINICAL DETAILS:

A. RESERVOIR

1. Gross Storage capacity 1050.63 M cum (37.103 TMC)

2. Dead storage capacity at

sluice level.

38.03MCum (1.343 TMC)

3. Minimum draw down

level capacity

123.80 MCum (4.372 TMC)

4. Live storage 926.83 MCum (32.731 TMC)

5. Average River bed level RL 850.09 M (2789')

6. Deepest foundation

level

RL 835.16 M (2740')

7. Dead storage

level

RL 867.16 M (2845')

8. Crest level of spillway RL 881.48 M (2892')

9. Full Reservoir level RL 890.63 M (2922')

10. Maximum water level RL 890.63 M (2922')

11. Top level of Dam RL 894.59 M (2935')

12. Floor level of

drainage gallery

a) 848.57 M (2784') (Non-over flow section)

b) 850.40 M (2790') (Over flow section)

B. DAM

1. Type of structure Central Masonry spillway with side non-overflow

Dam with Zoned Earthen Dam flanks.

2. Length of Dam 4692 M (15394')

3. Maximum height of

Dam above River bed

level

44.50 M(146')



4. Maximum height of

Dam above the deepest

foundation

59.43 M (195')

5. Top width of Dam 5.49 M (18')

6. Free Board 3.96 M (13')

7. Crest shutters Six Radial gates of size 10.67 M X 9.14 M

(35' x 30')

8. Spillway piers 5 Nos of 6 Mtrs width

9. Maximum flood dis-

charge

4020.95 Cumec

(1,42,000 cusecs)

10. Designed flood dis-

charge

4740.20 cumec

(1,67,400 cusecs)

SUBMERSION:

1. Garden

2. Dry 13,000 Acres

3. Wet 3,000 Acres

4. Kharab and River por-

tion

5,008 Acres

Total 21,008 acres or say 8502 Ha.

5. (1) No, of villages

submerged

46 villages

(2) No. of villages

partially affected

126 villages

Total 172 villages

(3) No. of families

affected

2283 Nos.



IRRIGATION SLUICES:

1. Left bank 5 Nos. 2.44 M x 3.05 M (8' x 10')

2. Right bank 4 Nos. 2.44 M x 3.05 M (8' x 10')

3. Sill level of sluices RL 867.15 M 2845'

4. High level Canal on Foreshore of

Reservoir

2 Nos.1.52 M x 3.05 M (5' x 10')

5. Sill level of High-level Canal RL 877.824 M (2880')

RIVER SLUICES: 5 Nos of 2.44 x 4.267 (8' x 14')

Sill level RL 854.9644 M (2805.00')

6. Length of the Dam 4.692 KM

a) Central masonry portion 366 M (spillway portion 94.5 M)

b) Left side earthen bund 1629 M

c) Right side earthen bund 1680 M

d) Dyke Dam 1017 M

7. Drainage gallery 354.6 M

a) Left side portion 145 M

b) Central portion 104 M

c) Right side portion 105.6 M

C. MAIN CANAL

I.SRI A.G. RAMACHANDRA RAO CANAL (H.L.B.C)

i. Length 214 Kms (133 Miles)

ii. Capacity at Head 103.04 Cumec (3639 cusecs)

iii. Designed Discharge at Head 103.13 Cumec (3642 Cusecs)

iv. Command 78,912.23 Ha. (1,95,000 acres)

v. Bed width in contour cut at Head 12.19 Mtrs (40')



vi. Full supply Depth 4.191 Mtrs (13.75')

vii Side slope in contour cut 1:1

viii. Coefficient of Rugosity 0.018 (lined canal)

II. SRI GORUR RAMASWAMY IYANGAR CANNAL (H.R.B.C.)



iii. Command 8094 Ha. (20,000 acres)

iv. Bed width at Head 7.32 Mtrs (24')

v. Full supply Depth 1.83 Mtrs (6')

vi. Side slope in contour cut 1:1

vii Coefficient of Rugosity 0.018 (lined canal)

III. SRI B.N. BORANNAGOWDA CANAL (H.R.B.H.L.C)



iii. Command 22,662 Ha. (56,000 acres)

iv. Bed width at Head 4.70 Mtrs (15.42')

v. Full supply Depth 3.30 Mtrs (10.83')

vi. Side slope in contour cut 1:1


D. BRANCH CANALS

I.TUMKUR BRANCH CANAL



iii. Command 95,909 Ha. (2,37,000 acres)



iv. Bed width at Head in contour cut 5.8 Mtrs (19.03')

v. Full supply Depth 3.45 Mtrs (11.32')

vi. Side slope 1:1


II. NAGAMANGALA BRANCH CANAL



iii. Command 59,488 Ha. (1,47,000 acres)

iv. Bed width at Head in contour cut 4.40 Mtrs (14.43')

v. Full supply Depth 3 Mtrs (9.84')

vi. Side slope 1:1


E. TUNNELS

I.BAGUR-NAVILE TUNNEL

i. Length 9.762 Kms

ii. Diameter 5.40 Mtrs (17.72')

iii. Shape “D” shape

iv. Discharging capacity 70.79 Cumec (2500 Cusecs)

v. Bed slope 1 in 660

vi. Area benefitted beyond Tunnel 1,55,396 Ha (3,83,000 acres)

vii. Original Estimate cost at 78-79

Rates

Rs.15.28 Crores

viii. Revised estimated cost of work Rs.30.61 Crores

ix. Date of commencement of work



a. 1st Reach 15-11-1979

b. 2nd Reach 15-12-1979

x. Anticipated date of completion October 1987

xi. Agency M/s Sree Srinivasa Construction company.

II. HEMAVATHY RIGHT BANK HIGH LEVEL CANAL TUNNEL

i. Length 3721 Kms

ii. Diameter 3.962 Mtrs (13')

iii. shape “D” shape

iv. Discharging capacity (a) Designed– 26.277 cumec (928 Cusecs)

(b) Required– 25.26 cumec (907 Cusecs)

v. Bed slope 1 in 3.88

vi. Area benefitted beyond Tunnel 22,662 Ha (56,000 acres)

vii Original Estimate cost at 79-80

Rates

Rs.354.00 Lakhs

viii Revised estimated cost of work

(85-86)

Rs.950.00 Lakhs

ix. Date of commencement of work 14-4-1980

x. Anticipated date of completion 30-6-1986

xi. Agency M/s Sri Srinivasa Construction company.

F. IRRIGATION DETAILS

a) Gross command

area

4,04,678 Ha.

(10,00,000 Acres)

b) Net irrigable area

i. By flow irrigation 2,65,064 Ha.

(6,55,000 acres)



ii. By Lift Irrigation on

canals

14,470 Ha.

(35,756 Acres)

iii. By Lift Irrigation

on Foreshore of

Reservoir

4,047 Ha.

(10,000 Acres)

Total 2,83,581 Ha.

(7,00,756 Acres)

c) Irrigation

Concentration

70.00 %

d) Cropping pattern

i. By gravity Irrigation under ca-

nals

a) Khariff Paddy 5,261 Ha (13000 Acres)

b) Khariff semi dry 1,53,980 Ha (380500 Acres)

c)Rabi Semi dry 1,05,823 Ha (261500 Acres)

Total 2,65,064 Ha (655000 Acres)

ii. By Lift Irrigation

under canals – 4

schemes

a) Khariff semi dry 14,470 Ha (35756 acres)

iii. By Lift Irrigation

on Foreshore of

Reservoir– 10 schemes

a) Khariff semi dry 4.047 Ha (10,000 acres)

G. DISTRICTS BENEFITTED

a) Under flow

Irrigation



i. Hassan Distirict 43,495 Ha (1,07,480 Acres)

ii. Manday Distirict 92,234 Ha (2,27,920 Acres)

iii. Mysore Distirict 2,266 Ha (5,600 Acres)

iv. Tumkur Distirict 1,27,069 Ha (3,14,000 Acres)

Total 2,65,064 Ha (6,55,000 Acres)

a) Under Lift

Irrigation

i. Hassan District 18.516 Ha (45,756 Acres)

H. YEAR OF COMMENCEMENT AND COMPLETION OF PROJECT

i. Year of commencement of work 1968

ii. Year of completion of project 1980

I. FINANCIAL ASPECTS

i. Cost of Dam and allied

works Rs.56.37 Crores

ii. Cost of canal,

Branches, Tunnel, etc., Rs.531.63 Crores

Total cost of the Project Rs.588.00 Crores

iii. Cost per Acre/Ha

Rs.8391.00 / Acre

Rs.20735.00 / Ha

iv. Benefit cost ratio 1.831

v. Revised cost of the project as

per the 2006-07 schedule of rates 3877.00 Crores

1.5 Assignment of Responsibility

The Cauvery Neeravari Nigama is the owner, final authority and responsibility for the operation

and maintenance of the dam. Identification of all areas of responsibilities connected with the



operation and maintenance of the dam are covered in this section. The officer’s responsibilities

for the various functions are identified by their designation and, in particular, the responsibilities

of operating personnel are specifically identified& includes regular scheduled duties which staff

personnel are required to perform as outlined in the following tables:

Table 2 – Overall Responsibilities for Hemavathy Dam

Sl No Particulars Remarks

1. • Implementing Agency

• CAUVERY NEERAVARI NIGAMA (A Govt. of

Karnataka Enterprise)

• Water Recourses Department, Karnataka

2. • Project Administration

Officer in charge • Managing Director, CNNL, Bengaluru

3. • Operations of Equipment

at the Dam

• Chief Engineer, CNNL, Hemavathy Project Zone,

Gorur

4. • Reservoir inflow and

Flood forecasting

• Executive Engineer, CNNL, Hemavathy Dam Divi-

sion, Gorur

5. • Authorizing spillway

flood releases


Gorur.

6.

• Authorizing releases for

various purposes like irri-

gation, water supply

hydro-power, etc


Gorur as per the proceedings of the Irrigation Consul-

tative Committee meeting (ICC) and in consultation

with Managing Director, CNNL Bengaluru

7. • Recording reservoir Data • Executive Engineer, CNNL, Hemavathy Dam Divi-

sion, Gorur

8. • Routine inspection • Executive Engineer, CNNL, Hemavathy Dam Divi-

sion, Gorur

9. • Maintenance Executive Engineer CNNL, Hemavathy Dam Divi-

sion, Gorur

10. • Instrumentation Executive Engineer CNNL, Hemavathy Dam Divi-

sion, Gorur



1.5.1 Roles and Responsibilities of the AEE and AE during Monsoon

Table 3 – Roles & Responsibilities of AEE & AE

Step Flood condition assessment, warning, flood mitigation, and other responsi-

bilities

1.

Coordinate with the CWC Authorities/ Engineers who maintains the records of

Hemavathy river inflow details at gauging station near Sakleshpur Town which is

around 50kms from the dam site by phone call. The rainfall data in the catchment

area obtaining through message to mobile phones by KSNDMC and bring it to the

notice of the EE/SE/CE

2. Assist the EE/SE/CE to issue notification to the villagers downstream in Newspa-

pers, Radio, TV News channel to be alert regarding the flood situation

3.

Assist the EE/SE/CE to coordinate with the Revenue authorities (District Admin-

istration) to alert the downstream villagers to evacuate the flood zone to prevent

loss of life and live stock

4. Assist the EE/SE/CE to coordinate with the CWC flood monitoring authorities on

the flood condition

5. Maintain the reservoir water level gauge register and to update on hourly basis dur-

ing floods. and to bring to the notice of EE/SE/CE

6. Assess the inflows in the reservoir as per the approved reservoir operation and to

prepare proforma consisting of the status of the reservoir capacity and releases from

the reservoir as per the standard Performa and to submit to the EE/SE/CE

7. Submit to the EE/SE/CE on the inflows and releases from the reservoir and status

of the reservoir twice in the day

8. Maintain the spillway crest gate operation log book

9. Operate the Spillway crest gates for flood mitigation as per the instructions of the

EE/SE/CE and to update the Gate operation Log book

10.

Observe the seepages in the drainage Gallery with respect to the reservoir head and

record the seepages in the infiltration gallery and to immediately bring to the notice

of the EE/SE/CE in case of excessive seepage, leakage in any porous drains

11. Maintain the pump operation log books for the dewatering pumps in the drainage

gallery and to submit to EE/SE/CE

12. Observe the gates and to see that the drain holes are not clogged and floating debris

is not deposited in the gate components



13.

Monitor the condition of the Welding transformers, gas cutting sets, umbrellas, tool

kits torches chain blocks ropes ballies etc on daily basis and to see that things are in

place to handle any emergency situation

14.

Observe the Gates, hoists and handling equipment during operation for the smooth

movements and to immediately report any untoward excessive sounds in the mo-

tors, pumps or vibrations in the gate

15. Observe the dam top, embankment, catwalk, approach roads are well maintained by

housekeeping personnel

16.

Observe the performance of the Dam and its appurtenant structures / Gates and

Hoists during flood water releases and to report to the EE/SE/CE in case of any

untoward incidents or malfunctioning of the gates of excessive seepages, leakages

etc.

17. Assist EE/SE/CE to coordinate & share the details of flood discharges from the

dam with the downstream Krishnarajasagara Dam Project Engineers

18. Assist EE/SE/CE to share the flow data and the reservoir storage details to the

Media on day to day basis

1.5.2 Roles and Responsibilities of the SE and EE during Monsoon

Table 4 – Roles & Responsibilities of SE & EE

Step Flood condition assessment, warning, flood mitigation and other responsi-

bilities

1.

Coordinate with the CWC Authorities/ Engineers who maintains the records of

Hemavathy river inflow details at gauging station near Sakleshpur Town which is

around 50kms from the dam site by phone call. The rainfall data in the catchment

area obtaining through message to mobile phones by KSNDMC and bring it to the

notice of the CE

2. To issue notification to the villagers downstream in Newspapers, Radio, TV News

channel to be alert regarding the flood situation

3.

Assist the CE to coordinate with the Revenue authorities (District Administration)

to alert the downstream villagers to evacuate the flood zone to prevent loss of life

and live stock

4. Assist the CE to coordinate with the CWC flood monitoring authorities on the flood

condition



5. Submission of inflows and releases from the reservoir and status of the reservoir

twice in a day to the CE

6. Operate the Spillway crest gates for flood mitigation as per the instructions of the

CE and to update the Gate operation Log book

7.

Observe the seepages in the drainage Gallery with respect to the reservoir head and

record the seepages in the infiltration gallery and immediately bring to the notice of

the CE in case of excessive seepage, leakage in any porous drains

8.

Observe the Gates, hoists and handling equipment during operation for the smooth

movements and to immediately report any untoward excessive sounds in the mo-

tors, pumps or vibrations in the gate

9. Observe the dam top, embankment, catwalk, approach roads are well maintained by

housekeeping personnel

10.


Hoists during flood water releases and to report to the CE in case of any untoward

incidents or malfunctioning of the gates of excessive seepages, leakages etc.

11. Assist CE to share the flow data and the reservoir storage details to the Media on

day to day basis

12. Assist CE to coordinate with the Project Engineers of Krishnarajasagar Project and

sharing the details of the flood condition in the river and the reservoir releases

1.5.3 Roles and Responsibilities of the Chief Engineer during Monsoon

Table 5 – Roles & Responsibilities of the Chief Engineer

Step Flood condition assessment, warning and flood mitigation

1.

Has to study the flood condition of the dam along with the SE, EE and other

dam concerned officers. Instruct the officers concerned to take immediate steps

to evacuate the excess flood with the available provisions and to give vast publi-

cation to the livestock at the downstream of the reservoir. At the same time has

to communicate and share the flood condition and action taken report with the

district disaster management and other state authorities concerned

2. Coordinate with the CWC flood monitoring authorities on the flood condition

3.

Issue necessary instructions to the engineers to Operate the reservoir based on the

inflows, rainfall data, releases from the upstream reservoirs and status of the

reservoir

4.


Hoists during flood water releases and to issue necessary instructions to the

AEE/EE/SE

5. Coordinate with the downstream Krishnarajaasagar Dam Project Engineers



6. Conduct Pre and Post Monsoon inspections of the Dam

1.6 Collection & Reporting of Dam and Reservoir Data

A proforma is provided (Table 6) to ensure that dates and times for the collection and reporting

of vital information is recorded and documented for the record.

• Reservoir water surface elevation.

• Reservoir inflow.

• Spillway outflow.

• River releases.

• Irrigation and water supply.

• Weather related data

• Instrumentation data

• Water quality

Instructions and a standard proforma for collection and reporting of inflow and outflow data, and

other pertinent data, is shown in Table 6 below.

Records [Logbooks] of the following operations at Hemavathy Dam are to be maintained in a

chronological manner for reference. These records are helpful for identifying preventative mainte-

nance measures that may need to be taken up, troubleshooting the cause of potential equipment

failure and documenting development of any unusual conditions.

• Date and Time

• Attendance statement during normal operations – both during monsoon and non-mon-

soon periods.

• Operations of the spillway gates and outlet works.

• Operating hours of mechanical equipment.

• Testing / Operation of spillway gates and associated controls.

• Testing/operation of Outlet gates and associated controls,

• Maintenance activities carried out.

• Reservoir and dam inspections.

• Unusual conditions or occurrences, including acts of vandalism.

• Attendance statement at the dam during emergency operations.

• Changes to normal operating procedures.



• Communication network checks.

• Safety and special instructions.

• Names of officers and staff carrying out inspections and maintenance.

• Any other item pertaining to the operation and maintenance of the dam.



Table 6–Example Proforma for recording Flow Data

Date Time

Water

level

in

feet.

Inflow in Cusecs

Out Flow in Cusecs

Reservoir Ca-

pacity in TMC

Spillway

Gates

HLBC

HRBC

HRBHLC

River

Total

O/F

Footnote 1: To be indirectly calculated as per examples 1 and 2 in Chapter 2, Paragraph 2.2.6.2& 2.2.6.3

Legend

• HLBC : Hemavathy Left Bank Canal

• HRBC : Hemavathy Right Bank Canal

• HRBHLC: Hemavathy Right Bank High Level Canal

• RIVER: Hemavathy River



1.7 Public and Project Staff - Health and Safety

As safety of Project Staff is of prime concern, safety instructions & protection measures at the

dam are carried out by all staff/ project personnel. The flex boards and warning boards provided

at deferent places provide the public notices of events and status of security of the dam and down-

stream river conditions.

1.7.1 Restricted Areas

Certain areas of the dam and reservoir are restricted for entry of the general public. The purpose

of restrictions is for security of the dam, public safety and uninterrupted safe operation of the dam.

Restricted areas include the following:

• Gallery.

• Spillway approach areas, chutes and stilling basin.

• Control buildings.

• Intake or outlet channels adjacent to hydraulic structures.

• Upstream and downstream slopes/faces of the dam.

1.7.2 Details of the Security arrangements at Hemavathy Dam Site.

The security arrangements of Hemavathy Dam are entrusted to the Karnataka Police department

with a total strength as below.

1. Assistant Head Constable (AHC)

Two Assistant Head Constables are deployed as head security officers in 2 shifts.

2. Assistant police constable (APC)

Ten Assistant police constables are deployed specially for the security at dam spillway por-

tion where public visitors are more.

3. Home guards Security personnel

21 Home guards Security personnel are deployed at different parts of the Hemavathy dam

such as entrance gates to the dam premises from HPC road, at the dam approach points,

canal head sluice buildings, dam main entrances, control room, gallery audits, check posts,

head works and as required depends on the strength of dam visitors.



Figure 3 Layout of Hemavathy Dam Premises



1.8 Staff Position, Communication & Warning System

The number & description of operating unit personnel/staff posted at different locations of the

dam may vary according to requirement during monsoon / non-monsoon periods. An engineering

organizational chart is shown in Figure 4below.

The means of communications both in normal and emergency situations are identified in the Com-

munication Directory found below. Available communication means including landline, mobile

phones to maintain security of the dam.

A utility room located on the downstream and in front of the dam is an equipment room with all

essential small tools, welders, gas cutter sets, chain blocks and ropes, space for the hydraulic hoist,

dewatering pumps, weather gear, and consumables to facilitate O&M requirements.

A brief description of the warning systems including alarms at the dam is mentioned in the Manual.

This includes information on downstream inundation areas during scheduled or unscheduled re-

lease of flood outflows from the spillway. Basic facilities like communication facilities, sirens etc.

are provided.



C Manjappa ,Chief Engineer(I/C) CNNL, Hemavathy Project Zone, Gorur

Land Line: 08172 – 225414 Mobile No : 9448088467

Email:[email protected]

S V Sreenatha, Assistant Executive Engineer

CNNL, Hemavathy Dam Division, Gorur

Land Line: 08172 – 225427 Mobile No : 9448871009


Gangadhar ,Executive Engineer (I/C) CNNL, Hemavathy Dam Division, Gorur

Land Line: 08172 – 225425 Mobile No : 94484 27354


C M Venkataravanappa, Assistant En-

gineer CNNL, Hemavathy Dam Division,

Gorur

Land Line : 08172-225427

Mobile No : 9845905745

Email : venkataravanap-

[email protected]

C Manjappa ,Superintending Engineer CNNL, Hemavathy Project Circle,

Gorur

Land Line:08172 – 225423 Mobile No : 9448088467


Figure 4 Organization Chart



1.8.1 Schedule of General Duties for Project Engineers

Schedules of duties being performed by the staff assigned to various locations and components of

Hemavathy Dam are provided in this section. All activities are to be recorded daily in the Logbook

and site registers.

DAILY

✓ Visual inspection of dam

➢ Crest of dam (Dam top)

➢ Upstream and downstream faces

➢ Visible portions of foundation and abutments contacts

➢ Galleries

✓ Record water surface elevation. (during monsoon on hourly basis)

✓ Record reservoir inflow and spillway discharge. (during monsoon on hourly basis)

✓ Record releases from outlets /sluices.

✓ Record seepage from drainage systems-Toe drains, Gallery drains etc. on daily basis

✓ Record meteorological data.

✓ Check security and safety devices.

✓ Complete logbook / site registers which should include the above information

WEEKLY

Electrical System

✓ Standby generator (DG Sets)

➢ Run for 15-30 min to achieve recommended operating temperature

➢ Check status of batteries and keep them charged.

➢ Check Fuel Supply

✓ Drainage systems - Toe drains, Gallery drains etc., and, during any reservoir filling opera-

tions.

MONTHLY

Check condition of:



Dam and Reservoir

✓ Reservoir periphery (daily during Monsoon)

✓ Drainage systems - Toe Drains, Gallery drains etc. (on regular basis)

✓ Measuring devices/Instruments

✓ Security and safety devices – rectification, if needed.

✓ Communication Devices

✓ Status of Vegetation growth

✓ Check Sign/Warning display boards near vulnerable locations are in place and updated as

necessary

Mechanical/Electrical System

✓ Replace fuses/light bulbs, as necessary

✓ Inspect and maintain ventilation system; check for and remove any obstructions

✓ Cleaning of control panel boards

QUARTERLY

Outlet Works

✓ Availability of updated operating instruction

✓ Check gate air vents

✓ Clean gate control switchboxes

✓ Check operation of gates and valves

✓ Grease gate hanger / dogging arrangements

Check

✓ Check condition of Outlet works &the Energy Dissipation Arrangement (EDA)

Spillway

✓ Check for debris in inlet channel

✓ Check operation of gates



✓ Check for damages in spillway glacis, EDA, d/s area, etc.

✓ Check and clear spillway bridge drains

Other works

✓ Check for adherence to instrumentation schedule

✓ Record pertinent information in Operation Log

✓ Check conditions of V-notch weirs/other seepage measuring devices

BI-ANNUAL

Spillway & outlet works

✓ Check paint on gates and other areas of corrosion

✓ Check lubrication of wire ropes and application of cardium compound.

✓ Check gear systems

✓ Exercise gates for operational efficiency

✓ Lubricate gate rollers

✓ Check rubber seals and seal clamp bar

Electrical System and Equipment

✓ Change oil in stand by generator

✓ Check exposed electrical wiring of:

➢ Operating equipment of gates of Outlet works.

➢ Operating equipment of gates of Spillway.

➢ Operating equipment of any other gates in dam

➢ Spillway catwalk / bridge

➢ Dam Gallery

✓ Check Gate limit switches and adjust



ANNUAL

Spillway &Outlet works

✓ Paint

➢ Metal work, Gate and all exposed metal parts for corrosion

✓ Electro-mechanical power pack system

✓ Exercise Gates

✓ Examine stilling basin / energy dissipation arrangement and d/s channel & carry out rec-

tification works, as necessary.

✓ Check metal welds for damages/cracks in Gates, Radial Gate Tie flats, Trunnion Gird-

ers/supports etc.

Electrical

✓ Check electrical conduits, pull-boxes and switches for:

➢ Outlet works

➢ Gates

➢ Spillway bridge

➢ Gallery

FIVE YEAR (PERIODIC)

✓ Inspect intake structures and stilling basin / energy dissipation arrangement, which nor-

mally are underwater; less frequent if experience indicates. This may need to be done by

carrying out dewatering or by divers/remote operated vehicle (ROV) as necessary.

✓ Review Dam operation procedures and EAP and update as necessary.

1.8.2 Electro-Mechanical Inspections / Checks

Special duties performed for E-M operating personnel works are given in this section. Frequency

of inspections / checks for electro-mechanical components and necessary actions to be taken up

during maintenance.



1. Radial Crest Gates - 6 Nos.

a. Embedded Parts

b. Gate Structure

Sl.

No. Embedded Part Frequency

1 Regular inspection of the gate to be carried out daily to ensure that there

is no unusual development/ observation Daily

2 Check all welding for soundness & rectify defects Quarterly

3

Check welding between arms & horizontal girders as well as arms &

Trunnion with the help of magnifying glass for cracks/ defects and

rectify the defects.

Quarterly

4 Clean all drain boles including those in end arms, horizontal girders &

Trunnion Quarterly

Sl.

No. Embedded Part Frequency

1

Checking of seal beams. Seal Seats, Guide track & all other exposed em-

bedded parts with respect to their alignment, distortion: if any due to

continuous use, pitting and un-necessary cracks due to wear & carrying

out requisite repairs, rectification by welding, grinding etc.

Half

Yearly

2 Removing debris & other foreign material deposited on embedded parts

& cleaning the same Monthly

3 All cracks & defective weld joints to be as certained & rectified. Half

Yearly

4

All dirt, debris, grit, foreign material etc. to be removed from trunnion

assemblies as well as trunnion chair and lubricate trunnion bearing & the

sliding surface on trunnion chair with specified lubricant/ grade to

ensure smooth sliding movement of trunnion.

Monthly

5

All nut bolts connecting Trunnion Assembly & Trunnion Chair and

Trunnion & Yoke, girder Trunnion pin lock plate to be checked &

Tightened and replace the same if found defective.

Monthly



5 Check all nuts & bolts provided and tighten them, and replace the defec-

tive nuts & bolts Quarterly

6

Check upstream face of Skin plate for pitting, scaling and corrosion.

Scaling formation are to be removed. Pitting shall be filled with weld&

ground. Corroded surface shall be cleaned & painted

Yearly

7

Joints of side& bottom rubber seals to be checked for their proper align-

ment and fixing & to be rectified/ adjusted if there is leakage through

joints

Monthly

8 Nuts & bolts for rubber seal connection to be tightened and damaged

nuts and bolts to be replaced Quarterly

9 The excessive or widespread leakages if any shall be reported to the

engineer in charge. Quarterly

10 The guide roller pin is to be lubricated Quarterly

1.9 Distribution of Operation & Maintenance Manuals

The list of unit officers to whom the O&M Manual is required to be distributed is shown in the

table below.

Table 7- Distribution of O&M Manual and Revisions

Sl No Unit Officers Number of Manual

Distribution

1. Secretary to Govt, Water Resources Department,

Vikasa Soudha, Bengaluru 3

2. Managing Director, CNNL, Bengaluru 2

3. Chief Engineer, CNNL, Hemavathy Project zone,

Gorur. 2

4. Chief Engineer, Water Resources Development Organ-

ization, Bengaluru. 1

5. Director, KERS, K R Sagara. 1

6. Superintending Engineer, SPMU, WRDO, Bengaluru 1

7. Superintending Engineer, CNNL, Hemavathy project

circle, Gorur. 1

8. Executive Engineer, SPMU, DRIP Bengaluru 1



9. Deputy Chief Engineer, CNNL, Hemavathy Project

zone, Gorur 1

10. Executive Engineer, CNNL, Hemavathy Dam Division,

Gorur. 1

11. Executive Engineer, Monitoring and Evaluation, Benga-

luru 1

12. TA to CE, Hemavathy Project zone, Gorur. 1

13. TA to SE, Hemavathy project circle, Gorur. 1

14. Assistant Executive Engineer, CNNL, Hemavathy Dam

Sub Division, Gorur. 1

15. Assistant Engineer-1, CNNL, Hemavathy Dam Sub Di-

vision, Gorur. 1

16. Technical Section of Central Office 1

17. Technical Section of Circle Office 1

1.10 Supporting Documents & Reference Material

This O&M Manual is the key instructive document. Supporting documents and necessary instruc-

tions for all phases of the operation, inspection and maintenance of the dam, reservoir and appur-

tenant works shown below are available at the dam control room:

• Emergency Action Plan (EAP)

• Flood forecasting and operating criteria

• Basin or river operating plan

• Interstate agreements

• Agreements with other user agencies

• Power station operation plan

• Irrigation operation plan

• Domestic / industrial water supply oper-

ating instructions

• Administrative procedures

• Reservoir / River pollution contingency

plan

• Maintenance schedules

• Gate Manufacturer’s instructions and

drawings

• Regional communication directory

• Instrumentation reports / results


Page 36

CHAPTER 2. PROJECT OPERATION

2.1 Basic Data

The Hemavathy operation plan consists of step-by-step instructions for operating the dam and res-

ervoir during routine (normal) and emergency conditions. The operating procedures for normal op-

erations are discussed in in this chapter including operating criteria for the reservoir, spillway &out-

lets. The operation of a dam involves regulation of its reservoir as per project specific require-

ments. This includes the use of area capacity curves and design flood; both are described below.

2.1.1 Area Capacity curves.

The area capacity curves for Hemavathy Dam in tabular and graphical form are shown in Table 8

and Figure 5.


Page 37

Figure 5 Area Capacity Curve


Page 38

Table 8- Elevation - Capacity Table for Hemavathy Reservoir

Sl.

No.

Reduced

level in

feet.

Area in

Acres.

Difference

in area be-

tween levels

Capacity

in Mcft.

Difference in

capacity be-

tween levels

Remarks

1 2 3 4 5 6 7

1 2790.00 River Bed level

2 2835.00 2043.00 401.70

3 2845.00 2943.01 1343.00

Sill level of the

irrigation sluices

of HLBC and

HRBC.

128.50 211.60

4 2846.00 3071.50 1554.60

128.50 211.5

5 2847.00 3200.00 1766.10

117.00 124.50

6 2848.00 3317.00 1890.60

117.00 124.40

7 2849.00 3434.00 2015.00

100.00 168.90

8 2850.00 3534.00 2003.90

100.00 168.90

9 2851.00 3634.00 2352.80

100.00 162.60

10 2852.00 3734.00 2515.40

100.00 162.70

11 2853.00 3834.00 2678.10

102.00 171.30

12 2854.00 3936.00 2849.40

102.00 171.30

13 2855.00 4038.00 3020.70

105.00 180.40

14 2856.00 4143.00 3201.10

105.00 180.40

15 2857.00 4248.00 3381.50


Page 39

Sl.

No.

Reduced

level in

feet.

Area in

Acres.

Difference

in area be-

tween levels

Capacity

in Mcft.

Difference in

capacity be-

tween levels

Remarks

106.00 189.60

16 2858.00 4354.00 3571.10

106.00 189.70

17 2859.00 4460.00 3760.80

129.00 199.40

18 2860.00 4589.00 3960.20

129.00 199.50

19 2861.00 4718.00 4159.70

158.00 212.35

20 2862.00 4876.00 4372.05

158.00 212.35

21 2863.00 5034.00 4584.40

161.50 226.35

22 2864.00 5195.50 4810.70

161.50 226.30

23 2865.00 5357.00 5037.00

140.50 240.50

24 2866.00 5497.50 5277.50

140.50 240.50

25 2867.00 5638.00 5518.00

197.00 345.00

26 2868.00 5835.00 5863.00

197.00 345.00

27 2869.00 6032.00 6208.00

191.50 181.00

28 2870.00 6223.50 6389.00

191.50 181.00

29 2871.00 6415.00 6570.00

213.00 288.70

30 2872.00 6628.00 6858.70

213.00 288.70

31 2873.00 6841.00 7147.40


Page 40

Sl.

No.

Reduced

level in

feet.

Area in

Acres.

Difference

in area be-

tween levels

Capacity

in Mcft.

Difference in

capacity be-

tween levels

Remarks

222.50 307.70

32 2874.00 7063.50 7455.10

222.50 307.70

33 2875.00 7286.00 7762.80

213.70 363.10

34 2876.00 7499.70 8125.90

213.66 363.03

35 2877.00 7713.36 8488.93

213.64 363.07

36 2878.00 7927.00 8852.00

296.30 407.70

37 2879.00 8283.30 9259.70

296.30 406.70

38 2880.00 8519.60 9666.40

Sill level of the irri-

gation sluices of

HRBHLC.

296.30 407.70

39 2881.00 8815.90 10074.10

296.30 406.70

40 2882.00 9112.20 10480.80

295.90 407.10

41 2883.00 9408.10 10887.90

295.90 407.10

42 2884.00 9704.00 11295.00

296.70 407.30

43 2885.00 10000.70 11702.30

296.70 407.30

44 2886.00 10297.40 12109.60

296.30 407.70

45 2887.00 10593.70 12517.30

296.30 407.70

46 2888.00 10890.00 12925.00


Page 41

Sl.

No.

Reduced

level in

feet.

Area in

Acres.

Difference

in area be-

tween levels

Capacity

in Mcft.

Difference in

capacity be-

tween levels

Remarks

354.60 562.75

47 2889.00 11244.60 13487.75

354.60 562.75

48 2890.00 11599.20 14050.50

354.60 563.25

49 2891.00 11953.80 14613.75

354.60 563.25

50 2892.00 12308.40 15177.00 Crest level

354.60 563.25

51 2893.00 12663.00 15740.25

354.60 563.25

52 2894.00 13017.60 16303.50

354.60 563.25

53 2895.00 13372.20 16866.75

354.60 563.25

54 2896.00 13726.80 17430.00

354.60 563.25

55 2897.00 14081.40 17993.25

354.60 563.25

56 2898.00 14436.00 18556.50

354.60 563.25

57 2899.00 14790.60 19119.75

354.60 563.25

58 2900.00 15145.20 19683.00

165.00 665.80

59 2901.00 15310.20 20348.80

165.00 665.80

60 2902.00 15475.20 21014.60

185.00 680.10

61 2903.00 15660.20 21694.70

185.00 680.10

62 2904.00 15845.20 22374.80


Page 42

Sl.

No.

Reduced

level in

feet.

Area in

Acres.

Difference

in area be-

tween levels

Capacity

in Mcft.

Difference in

capacity be-

tween levels

Remarks

132.00 691.20

63 2905.00 15977.20 23066.00

256.00 700.00

64 2906.00 16233.20 23766.00

250.00 715.80

65 2907.00 16483.20 24481.80

250.00 715.80

66 2908.00 16733.20 25197.60

281.30 738.25

67 2909.00 17014.50 25935.85

281.30 738.25

68 2910.00 17295.00 26674.10

446.10 769.95

69 2911.00 17741.90 27444.05

446.10 769.95

70 2912.00 18188.00 28214.00

431.00 811.50

71 2913.00 18619.00 29025.50

431.00 811.50

72 2914.00 19050.00 29837.00

460.00 850.00

73 2915.00 19510.00 30687.00

460.00 850.00

74 2916.00 19970.00 31537.00

295.00 889.00

75 2917.00 20265.00 32426.00

295.00 889.00

76 2918.00 20560.00 33315.00

595.00 927.50

77 2919.00 21155.00 34242.50

595.00 927.50


Page 43

Sl.

No.

Reduced

level in

feet.

Area in

Acres.

Difference

in area be-

tween levels

Capacity

in Mcft.

Difference in

capacity be-

tween levels

Remarks

78 2920.00 21750.00 35170.00

445.00 966.50

79 2921.00 22195.00 36136.50

445.00 966.50

80 2922.00 22640.00 37103.00

Maximum water

level (same as

FRL)

445.00 1005.00

81 2923.00 23085.00 38108.00

2.1.2 Design Flood and Features Related to Safety

The total maximum flood design at Hemavathy Dam site was earlier fixed at 4020.95 cumec. This

was based on the unit hydrograph studies for a return period of 100 years .The spillway is designed

for a flood discharge of 3624.52 cumec through 6 Nos. of radial gates of size 10.66 m horizontal and

9.14 m height with free flow condition and the flood discharge through 5 Nos. of river sluice gates

of size 2.44 m horizontal and 4.26 m height is off 1115.67 cumec. The total dischargeable flood is

4740.19 cumec which is more than the initial design flood of 4020.95 cumec. This design flood has

been revised by Karnataka Engineering Research Station authorities, Mysuru. The revised inflow

flood value of10934 cumec corresponding to PMF has been approved by Hydrology (south) direc-

torate, CWC, New Delhi during 2016.Flood routing study carried out for the revised design flood

(PMF) resulted in MWL of 891.483 m, which is 0.85 m above the original MWL/FRL. A summary

of results corresponding to the MWL of 891.483 is summarized below in the form of map, tabular

and graph.

Table 9 - Details of Peak floods for different sub catchments

Time in Hrs

Routed Flood ordinate of Sub Catchment B2

Routed Flood ordinate of Sub Catch-ment B3

Flood ordinate of Catchment Bl

Flood ordinate of Catchment A

Total Flood ordinates at Hemavathy

Dam

0 27.6 5.5 44.5 67.9 145.5

1 27.6 5.5 44.5 67.9 145.5

2 27.6 5.5 44.5 67.9 145.5

3 27.6 5.5 44.5 67.9 145.5

4 27.7 5.5 44.5 67.9 145.6

5 27.7 5.5 45.3 68.7 147.2


Page 44

Time in Hrs






Dam

6 27.7 5.5 47.4 71 151.6

7 27.7 5.5 52.8 76.5 162.5

8 27.8 5.6 65.2 88.7 187.3

9 28.4 5.9 81.9 104.6 220.8

10 30.3 6.9 103.8 122.3 263.3

11 35.3 9.6 130.7 141.1 316.7

12 46.6 15.3 161.9 160.9 384.7

13 68.4 25.9 200.7 184.5 479.5

14 105.4 42.2 251.1 213.3 612.0

15 160.6 63 311.4 248.1 783.1

16 233 84.3 385.7 289.5 992.5

17 315.5 100.2 478.1 340.6 1234.4

18 394.6 107 566 408.1 1475.7

19 455.8 105.6 654.2 497.5 1713.1

20 491.7 100.8 742.8 619.4 1954.7

21 506.3 98.7 826.7 762.8 2194.5

22 513.4 103.5 923.2 904 2444.1

23 531.3 117.7 1036 1043.3 2728.3

24 577 143.1 1165.9 1177.4 3063.4

25 664 181.7 1310.7 1307.4 3463.8

26 801.3 234.5 1476.5 1437.4 3949.7

27 991.4 297.7 1656.8 1570.7 4516.6

28 1225.9 359.9 1859.2 1712 5157.0

29 1479.1 404.6 2085.5 1865.1 5834.3

30 1707.9 419 2265.7 2040.3 6432.9

31 1864.4 401 2392.2 2237.6 6895.2

32 1915.9 358.5 2440.6 2462.4 7177.4

33 1857.00 303.5 2408.9 2699.7 7269.1

34 1707.7 247.5 2315.4 2896.2 7166.8

35 1503.6 199.3 2186 3050.4 6939.3

36 1284.9 164.5 2037.5 3148.8 6635.7

37 1087.5 146.1 1880.8 3188.5 6302.9

38 937.8 144.2 1742.1 3169.1 5993.2

39 849.1 155.6 1637.1 3111.7 5753.5

40 820.9 173 1579 3033.8 5606.7


Page 45

Time in Hrs






Dam

41 838.9 187.2 1571.8 2948.1 5546.0

42 878 191.6 1583.1 2869.1 5521.8

43 912.6 186.4 1614.9 2811.7 5525.6

44 927.1 177.8 1661.4 2800 5566.3

45 923.3 173.8 1711.5 2823.5 5632.1

46 917.5 180.3 1787 2850.6 5735.4

47 933.1 200.3 1893.8 2880.1 5907.3

48 992.3 236.2 2036.6 2913 6178.1

49 1112.7 291 2204 2951.8 6559.5

50 1305.8 365.8 2408.3 3005.6 7085.5

51 1574.3 455.2 2638.2 3080.4 7748.1

52 1905.7 543 2903 3184.5 8536.2

53 2263.3 605.8 3204.9 3317 9391.0

54 2585 625.2 3438.5 3487.8 10136.5

55 2802 597.7 3587.4 3691.1 10678.2

56 2866.1 533.1 3608 3926.9 10934.1

57 2766.4 447.6 3501.7 4176.8 10892.5

58 2527.1 356.5 3288.5 4369.4 10541.5

59 2193.9 271.7 3006.6 4501.9 9974.1

60 1818.4 199.4 2681.9 4553.4 9253.1

61 1446.2 141.7 2326.3 4512.8 8427.0

62 1109.8 97.7 1972.5 4377.6 7557.6

63 826.6 65.5 1649.2 4171.7 6713.0

64 600.4 42.7 1367.8 3919.5 5930.4

65 426.7 27.4 1127.1 3633.3 5214.5

66 297.5 17.6 927.4 3321.8 4564.3

67 204.3 11.8 762.4 2996.5 3975.0

68 139.2 8.5 623.6 2672.5 3443.8

69 95.5 6.8 505 2358.8 2966.1

70 67.2 6 401 2057.5 2531.7

71 49.7 5.7 312 1768 2135.4

72 39.4 5.6 242 1498.5 1785.5

73 33.7 5.5 180 1252.3 1471.5

74 30.6 5.5 131.9 1033.8 1201.8

75 29.1 5.5 95.7 845.7 976.0


Page 46

Time in Hrs






Dam

76 28.3 5.5 70.3 690.3 794.4

77 27.9 5.5 57.0 560.8 651.2

78 27.8 5.5 49.5 452.6 535.4

79 27.7 5.5 46.0 362.8 442.0

80 27.7 5.5 44.5 289.9 367.6

81 27.7 5.5 44.5 230 307.7

82 27.7 5.5 44.5 182.3 260.0

83 27.7 5.5 44.5 144.2 221.9

84 27.7 5.5 44.5 113.5 191.2

85 27.7 5.5 44.5 90.9 168.6

86 27.7 5.5 44.5 79.7 157.4

87 27.7 5.5 44.5 72.9 150.6

88 27.7 5.5 44.5 69.4 147.1

89 27.7 5.5 44.5 67.9 145.6

90 27.7 5.5 44.5 67.9 145.6

Figure 6 - Peak flood (PMF) Hydrograph

10934.1

0.0

2000.0

4000.0

6000.0

8000.0

10000.0

12000.0

0 20 40 60 80 100

Dis

char

ge in

cu

mec

s

Time in Hours

Flood Hydrograph at Hemavathy Dam

Routed Flood ordinate of SubCactchment B2

Routed Flood ordinate of SubCactchment B3



Total Floodordiantes at Hemavathy Dam


Page 47

Figure 7 - Catchment area map with sub catchments

2.2 Flood Management at Hemavathy Reservoir

2.2.1 Gate Operations:

The Govt. of Karnataka have issued a circular for the gate operation of Hemavathy reservoir which

is as below.

DISCHARGE CHARACTERSTICS OF GATES

Thedischarging capacity of spillway gates/river sluice gates at different reservoir levels for each

gateand for all gates for different gate opening have been computed anddisplayed in the gate

operation room.

The Karnataka Engineering Research Station (KERS) has carried out model studies of Hemavathy

reservoir spillway and generated a table indicating the discharge with reference to gate opening versus

reservoir level and also for free-flowing condition which is being used for measurement of discharge

through spillway crest gates.

The discharges through river sluices and irrigation sluices are being determined by the formula

Q= 0.85*sqrt(2gH) *A.


Page 48

Where:

A = Area of sluice gate opening.

G = Acceleration due to gravity.

H = Height measured from water level in the reservoir to the centre of the opening.

It is ascertainedthat the time required for the water to flow into the Hemavathy Reservoir from

the catchment during rainy season is six hours.The safe discharge from Hemavathy reservoir into the

river is 30,000 cusecs.The Hemavathyreservoir has nofloodabsorption storage capacity above F.R.L.

as it affects the Sakaleshpur town .Hence it is indicated to have the flood absorption capacity in the

reservoir to the extent of 1 to 2 T.M.C during monsoon period.

RESERVOIR OPERATION SCHEDULE:

It is proposed to have 2 T.M.C ft. storage capacity as flood absorption below F.R.L during active

monsoon so as tohave safeand effective reservoir operation schedule.

The Gross storage capacity and reservoir level with 2 T.M.C ft., flood absorption capacity below

F.R.L is as shown below:-

Table 10- Details Showing the flood absorption capacity

The rainfall in the catchment area generally starts from 1st week of June and it is very heavy generally

during July, August and September Months.The recorded inflow in to the reservoir from 1977-1992

is as given below:-

Reservoir level In feet Capacity in Mcft. Difference in

Capacity b/n

F.R.L. 2922.00 37103 2000 M.C ft.

R.L 2919.87 35103 860 M.C ft

R.L 2919.00 34243


Page 49

Table 11 - Table showing the recorded inflow into the reservoir during monsoon period.

Sl No

Year

July August September October

In T.M.C

Maximum 24Hours Average inflowin cusecs

In T.M.C

Maximum 24 Hours Average inflowin cusecs

In T.M.C


In T.M.C


1 1977 24.29 20693 12.44 8434 14.75 1830 18.11 18830

2 1978 26.61 25400 47.33 39017 14.21 17797 8.20 5015

3 1979 14.31 19074 35.61 32656 11.50 8913 7.53 7720

4 1980 54.48 63087 26.14 16425 11.37 8414 7.09 5822

5 1981 19.96 25200 55.85 52640 18.31 15050 8.25 7660

6 1982 17.94 23300 32.97 33950 9.29 6090 7.10 7350

7 1983 18.43 31020 23.85 18812 16.07 12672 10.22 16261

8 1984 35.24 31798 19.12 14950 10.23 6911 9.98 12378

9 1985 9.95 6308 16.96 13688 4.84 4968 4.41 4733

10 1986 14.57 14155 28.78 34180 6.99 3991 5.54 4607

11 1987 7.88 9322 8.37 11829 5.49 4951 7.99 9141

12 1988 18.30 29943 17.85 23629 11.31 10081 5.27 4907

13 1989 24.87 48890 18.29 10902 6.45 4046 6.10 5086

14 1990 17.63 18365 25.85 24062 7.31 6779 6.30 6857

15 1991 38.49 63185 23.28 19622 6.32 4171 8.06 5060

16 1992 24.55 32606 33.33 33550 17.59 23033 14.45 27659

If the flood absorption capacity of2 TMcftis maintained the reservoir level has to be kept at

2919.87ft. i.e., 2.13 ft. belowF.R.L.As the maximum inflow into the reservoir during the month of

July and August is of the order of55 TMCft.as against the gross storage capacity of 37.103 TMCft.It

is better to start the reservoir operationscheduleduly predicting the inflow into the reservoir based

on gauged discharge at Sakaleshpurand at Belur gauge sites and also from the daily rainfall records

ofupstream rain gauge station in the catchment from 1st week of June itself.However the reservoir

level of R.L. 2919 with a cushion of 3 ft. should be maintained till the end of August by suitably

matchingthe inflow and outflow discharges.During the month of September dependingupon the

inflow pattern, the reservoir water level may be raised to safer level (i.e, 1 ft. below F.R.L).From

October and onwards the reservoir water level may be brought to the F.R.L level, depending upon

the inflow pattern and forecast of floods/monsoon.If any flash floods or cyclonic floods are expected

during October/November, careful prediction of inflows from the upper gauge stationsfrom the rain


Page 50

gauge stations and from weather forecast should be done and the reservoir operation in advance to

keep cushion for the inflow has to be carefully done.Advance warning with quantity of water to be

released into the river should be intimated to the concerned Deputy Commissioners of Hassan,

Mandya, Mysoresuperintendent of Police of Hassan, Mandya and Mysore,Chief Engineer, Irrigation

South, Mysore Superintending Engineer, Irrigation Investigation Circle, Mysore,Executive Engineer,

K.R.Sagar Division,K.R. Sagar and concerned Tahasildars through mobile phone.A wide publicity

through Radio, T.V. and Daily News papers to this effect should be issued.

These instructions should be followed scrupulouslyand action taken to be reported immediately.

Crisis Management Team in Central Office

‘A’ Team ‘B’ Team

SuperintendingEngineer Dy. Chief Engineer, O/o Chief Engineer,

TechnicalAssistant

O/o SuperintendingEngineer

TechnicalAssistant O/o Chief Engineer,

Assistant Engineer

O/o SuperintendingEngineer

Assistant EngineerO/o Chief Engineer,

( Similar teams at Division leveland Sub Division level should be formed)

The duties of Superintending Engineeris to monitorfor theflood operation from July to

November.He should bring it to the notice of Chief Engineer day to day flood discharge and when

the inflow/outflowincreases more than 20,000 cusecs, hourly inflow and outflowshould be

intimated.The other two Officers should assistthe Superintending Engineer in carrying out his duties.

In the absence of Chief Engineer from Headquarters Superintending Engineershould carry out

the duties of Chief Engineer.

2.2.2 Rule Curve

The Hemavathy Reservoir Rule curve is developed month vs storage capacity and month vs reservoir

level for the FRL of 2922.00 ft. and the same is shown in tabular as well as graphical forms below.

Table 12 -Rule curve table of Hemavathy Dam showing month and storage capacity

Month Storage capacity in TMC

January 15.392

February 14.485


Page 51

March 12.934

April 10.222

May 7.244

June 5.327

July 34.240

August 34.240

September 36.130

October 37.103

November 26.832

December 21.554

Figure 8 -Rule curve of Hemavathy Dam

The water releases to the irrigation and other purposes will be controlled by using the rule curve.

Table 13 -Rule curve table of Hemavathy Dam showing month and reservoir elevation.

Month Reservoir level in feet

January 2892.38

February 2890.77

March 2888.01

April 2881.36

May 2873.31

June 2866.2

0

5

10

15

20

25

30

35

40

Jan Feb Mar Aprl May June July Aug Sept Octo Nov Dec

Sto

rage

cap

acit

y in

TM

C

Month

Rule Curve


Page 52

July 2918.99

August 2918.99

September 2920.99

October 2922

November 2910.2

December 2902.79

Figure 9 - Rule curve of Hemavathy Dam

2.2.3 Flood Peaks of Different Return Periods

The flood peaks for different return periods shown in the table and figure below are as follows:

Table 14- Return Flow Peak Flows vs. Return Period Data

Note: Annual flow details for the Hemavathy river is available for 69years (1916-17 to 1984-85)

which has been predicted to 100 years with a reasonable factor of safety and used for the arrival of

design flood discharge in the Hemavathy reservoir. So the details are not available to show peak

inflow flood for the 1 in 100 year return period.

2850

2860

2870

2880

2890

2900

2910

2920

2930

Res

ervo

ir le

vel i

n f

eet

Month

Rule curve of Hemavathy dam

Return Period Years Peak Flow

MCum. MCft.

25 2485.54 87777

50 1907.20 67353

69 1268.69 44804

100 4020.95 141999

PMF 10934.00 386134


Page 53

During the monsoon period constant observation on peak inflows to the reservoir will be made

and flood controlling will be done according to the Karnataka Govt circular which enlighten the

guidlines for the reservoir operation.

Figure 10 -Peak Flows vs. Return Periods

2.2.4 Recommended Gate Operation Procedures for Normal Flow Conditions

During normal flow condition, the spillway radial crest gates will not be operated or are kept in closed

condition unless and otherwise there is a flash flood. The river sluice gates will be operated only

during the service & the discharge required for irrigating the command area coming under the century

old anicut canals in the river and also for the drinking water purpose for the villages coming all along

the river will be fulfilled by the hydro-power plant. Regarding the irrigation sluice gates is concerned,

the gates will be operated to allow the required discharge through the irrigation canals.

Table 15 -Details showing the monthly recommended water releases to the irrigation and drinking water supply.

Month

Recommended water releases in Mcft

Irrigation Drinking Wa-

ter Supply

June 133.03 17.28

July 1137.35 17.28

August 8530.70 17.28

September 10010.76 17.28

October 9928.81 17.28

November 7534.23 17.28

December 6525.46 17.28

January 2095.16 17.28

0

20000

40000

60000

80000

100000

120000

140000

160000

25 50 75 100

Pea

k Fl

ow

s

Return Period

Peak Flow in Mcum.

Peak Flow in MCft.


Page 54

February 571.92 17.28

March 707.52 17.28

April 619.09 17.28

May 464.20 17.28

2.2.5 Inflow Forecasting

The gross storage of Hemavathy Dam at FRL 890.63 m is 37.103 TMC. The revised design flood for

Hemavathy Dam is a probable maximum flood (PMF)of 10934 cumecs (3.86 lakh cusecs). The

impounding has started in the reservoir in the year 1977.

During monsoon, incident rains in the catchment area cause the flash floods in Hemavathy river.

These floods may lead to problems like people getting displaced from their homes, huge damage to

crops and other assets. The floods can have disastrous impact on the environment also. Adequate

measures are required to be taken up in advance to control and regulate the flow of water in the river.

The following measures are essential for effective management of floods in Hemavathy River

during the monsoons.

1) Nomination of liaising officers.

2) Sharing of directory of concerned officers responsible for flood management.

3) Exchange of data regarding rainfall, releases from dams, reservoir water levels.

4) Reservoir operation schedules.

Exchange of data regarding rainfall, releases from dams, reservoir water levels.

The Central water Commission has established office at Sakaleshpura town for assisting in flood

warning in the Hemavathy river basin. Based on the rainfall in the catchment and flow in the river

and tributaries, CWC office will furnish flood forecasting reports to CWC authorities. It also informs

the trend of flow (Raising, steady or Falling)

The list of rain gauges in the catchment of Hemavathy catchment area and daily rainfall is to be

collected by concerned offices. It will be helpful for prediction of probable floods in the river.

During monsoon daily water releases from the Dam at 8 hrs.& 16 hrs. in normal situation and

hourly data exchange during heavy floods is necessary. In this regard, the data is required to be es-

tablished. The data regarding exchange floods is made available to the Revenue authorities and public

by broadcasting in AIR, TV and publication in newspapers.


Page 55

Flood warning system in catchment area:

The regulation of flood from the catchment area of theHemavathy reservoir is very crucial to

quantify the inflow of floods into Hemavathy dam. The agencies of Central water Commission will

be coordinated to assist in the flood forecasting. Accordingly, the sequence of opening or closing of

gates will be taken up in accordance with the approved gate operation schedule.

Flood communication system:

The widely time-tested Communication to reach every and corner of the flood affected zones have

been radio and television and private media for the people to move to safer places by themselves in

an emergency.

Communication is very important in such occasions in these days due to revolution in the telecom-

munication system and network of mobile phones. Advantage of this facility will be taken. Mobile

numbers of all such staff will be listed and made available to all the personnel who have been assigned

duty of disaster management.

Following liasoning officers for flood coordination of Hemavathy Dam are as listed below

Karnataka State:

1) Chief Engineer, Phone No. 08172 – 225414 & 225415

2) Superintending Engineer, Phone No.08172- 225423 3) Executive Engineer, Phone No. 08172 - 225425 4) Asst. Executive, Engineer, Mobile No.9448871009

5) Asst.Engineer, Mobile No. 9845905745

6) District Administration Hassan, Phone No. 08172-267345

2.2.6 Methodology of Flood Regulation at Hemavathy

The Methodology is explained inspection 2.2 above.

2.2.6.1 Inflow Computation

Inflowinto reservoirs isnormally estimatedby the reservoirgauging method (also called the

rise and fall method or inflow-outflow method).All the outflowsare added togetherand to

it difference of capacities with respect to the reservoir levels at certain time intervals will

be added or substracted as case may be (raise or fall).


Page 56

2.2.6.2 Examples of Inflow Computation

Procedure for calculation of reservoir capacity and inflow

Step 1:-Consideringthe previous day’sreservoir leveland capacity as base material.

Step 2:-Taking the reservoir level from dam site.

Step 3:-Calculation of reservoir capacity for observed level byusing area- capacity table by

interpolation method.

Step 4:-Comparingthepresentdayreservoirarea and capacity with the previousday values.Step 5:-

Calculationoftotal outflows from the reservoir in the previous 24 hours

(including Hassan city drinking water supply).

Step 6:-Calcualtion of inflows by the addition oftotal outflows and difference ofcapacity which

arrived in step 4 (i.e., total outflows + reservoir capacity).

Example:-For date of 6-10-2016

Date Reservoir

level (in ft)

Capacity

(in Mcft)

Diff in

capacity

(in Mcft)

Area (in

acres)

Average

area (in

acres)

8-10-2016 2874.37 7568.95 7568.95 -

7882.62= -

313.67

7145.83

7251.18 7-10-2016 2875.33 7882.62 7356.52

Total outflows in the previous 24 hours :

1) River- 1200 cusecs

2) HLBC- 2845 cusecs

3) RBC-330 cusecs

Total- 4375 cusecsx0.0864=378.00 McftHassan city drinking water supply3.5 cusecs=0.30 Mcft

= 378.3 Mcft

Inflows=Total outflows+diff. in cpacity from table

378.30- 313.67 = 64.63 Mcft/0.0864 = 748 cusecs.



2.2.6.3 Computation procedure for Required Radial Crest Gate Opening

Karnataka Engineering Research Station (KERS) Mysore has provided a discharge chart containing the flood discharge for prescribed gate opening versus

Reservoir Level after conducting model studies in detail. The chart is as below.

Table 16 - Hemavathy reservoir project table of discharges over spillway v/s gate openings above gate seat.

SL.NO

Gate open-

ing/ Reser-

voir Eleva-

tion(feet)

Discharge in cusecs for gate openings above gate seat when all 6 gates are opened.

Free

Flow

condi-

tion

when all

the gates

are fully

opened

1/4' 1/2' 3/4' 1' 1/

1/4'

1/

1/2'

1/

3/4' 2'

2/

1/4'

2/

1/2'

2/

3/4' 3'

3/

1/2'

In cu-

secs

1 2892 - - - - - - - - - - - - - -

2 2893 - - - - - - - - - - - - - 800

3 2894 - - - - - - - - - - - - - 1800

4 2895 450 900 1350 1800 - - - - - - - - - 3300

5 2896 500 1000 1500 2000 - - - - - - - - - 4800

6 2897 538 1075 1613 2150 - - - - - - - - - 6600

7 2898 650 1300 1950 2600 - - - - - - - - - 9400

8 2899 700 1400 2100 2800 3425 4050 4675 5300 5925 6550 7175 7800 - 12000



9 2900 775 1550 2325 3100 3738 4375 5013 5650 6288 6925 7563 8200 9525 15200

10 2901 800 1600 2400 3200 3938 4675 5413 6150 6888 7625 8363 9100 10375 18400

11 2902 875 1750 2625 3500 4275 5050 5825 6600 7375 8150 8925 9700 11125 22400

12 2903 900 1800 2700 3600 4413 5225 6038 6850 7663 8475 9288 10100 11600 26000

13 2904 950 1900 2850 3800 4650 5500 6250 7200 8050 8900 9750 10600 12175 30400

14 2905 975 1950 2925 3900 4800 5700 6600 7500 8400 9300 10200 11100 12725 34800

15 2906 1000 2000 3000 4000 4950 5900 6850 7800 8750 9700 10650 11600 13300 39400

16 2907 1050 2100 3150 4200 5175 6150 7125 8100 9075 10050 11025 12000 13800 44100

17 2908 1075 2150 3225 4300 5313 6325 7338 8350 9363 10375 11388 12400 14250 48600

18 2909 1100 2200 3300 4400 5438 6475 7513 8550 9588 10625 11663 12700 14625 52800

19 2910 1125 2250 3375 4500 5600 6700 7800 8900 10000 11100 12200 13300 15250 57800

20 2911 1150 2300 3450 4600 5725 6850 7975 9100 10225 11350 12475 13600 15650 63000

21 2912 1175 2350 3525 4700 5875 7050 8225 9400 10575 11750 12925 14100 16175 68400

22 2913 1200 2400 3600 4800 6013 7225 8438 9650 10863 12075 13288 14500 16625 73400

23 2914 1225 2450 3675 4900 6138 7375 8613 9850 11088 12325 13563 14800 16975 79000

24 2915 1250 2500 3750 5000 6275 7550 8825 10100 11375 12650 13925 15200 17475 84800

25 2916 1275 2550 3825 5100 6388 7675 8963 10250 11538 12825 14113 15400 17775 92200

26 2917 1300 2600 3900 5200 6513 7825 9138 10450 11763 13075 14388 15700 18075 96800

27 2918 1313 2625 3938 5250 6594 7938 9281 10625 11969 13313 14656 16000 18450 103400

28 2919 1325 2650 3975 5300 6650 8000 9350 10700 12050 13400 14750 16100 18675 109400

29 2920 1350 2700 4050 5400 6775 8150 9525 10900 12275 13650 15025 16400 19000 116000

30 2921 1375 2750 4125 5500 6888 8275 9663 11050 12438 13825 15213 16600 19300 122600



31 2922 1400 2800 4200 5600 7025 8450 9875 11300 12725 14150 15575 17000 19700 129800

SL.NO

Gate open-

ing/ Reser-

voir Eleva-

tion(feet)


Free

Flow

condi-

tion

when all

the gates

are fully

opened

4' 4

/1/2' 5'

5

/1/2' 6' 7' 8' 9' 10' 11' 12' 13' 14'

In cu-

secs

1 2892 - - - - - - - - - - - - - -

2 2893 - - - - - - - - - - - - - 800

3 2894 - - - - - - - - - - - - - 1800

4 2895 - - - - - - - - - - - - - 3300

5 2896 - - - - - - - - - - - - - 4800

6 2897 - - - - - - - - - - - - - 6600

7 2898 - - - - - - - - - - - - - 9400

8 2899 - - - - - - - - - - - - - 12000

9 2900 10850 12175 13500 - - - - - - - - - - 15200

10 2901 11650 12925 14200 - - - - - - - - - - 18400

11 2902 12550 13975 15400 - - - - - - - - - - 22400

12 2903 13100 14600 16100 18000 19900 21800 - - - - - - - 26000



13 2904 13750 15325 16900 18900 20900 22900 - - - - - - - 30400

14 2905 14350 15975 17600 19600 21600 23600 - - - - - - - 34800

15 2906 15000 16700 18400 20533 22667 24800 27800 30800 - - - - - 39400

16 2907 15600 17400 19200 21433 23667 25900 29050 32200 - - - - - 44100

17 2908 16100 17950 19800 22133 24467 26800 30150 33500 - - - - - 48600

18 2909 16550 18475 20400 22800 25200 27600 31150 34700 - - - - - 52800

19 2910 17200 19150 21100 23567 26033 28500 32300 36100 39800 43500 - - - 57800

20 2911 17700 19750 21800 24333 26867 29400 33200 37000 40900 44800 - - - 63000

21 2912 18250 20325 22400 25000 27600 30200 34400 38600 42450 46300 - - - 68400

22 2913 18750 20875 23000 25767 28533 31300 35550 39800 43250 46700 - - - 73400

23 2914 19150 21325 23500 26367 29233 32100 36650 41200 45200 49200 - - - 79000

24 2915 19750 22025 24300 27233 30167 33100 38250 43400 46950 50500 55175 59850 64525 84800

25 2916 20150 22525 24900 28000 31100 34200 39150 44100 47950 51800 56650 61500 66350 92200

26 2917 20450 22825 25200 28433 31667 34900 39750 44600 48800 53000 57900 62800 67700 96800

27 2918 20900 23350 25800 29133 32467 35800 40800 45800 50050 54300 59375 64450 69525 103400

28 2919 21250 23825 26400 29867 33333 36800 41800 46800 51300 55800 60850 65900 70950 109400

29 2920 21600 24200 26800 30400 34000 37600 42500 47400 52200 57000 62100 67200 72300 116000

30 2921 22000 24700 27400 31133 34867 38600 43500 48400 53300 58200 63400 68600 73800 122600

31 2922 22400 25100 27800 31700 35600 39500 44400 49300 54350 59400 64700 70000 75300 129800



SL.NO

Gate open-

ing/ Reser-

voir Eleva-

tion(feet)


Free

Flow

condi-

tion

when all

the gates

are fully

opened

15' 16' 17' 18' 19' In cu-

secs

1 2892 - - - - - -

2 2893 - - - - - 800

3 2894 - - - - - 1800

4 2895 - - - - - 3300

5 2896 - - - - - 4800

6 2897 - - - - - 6600

7 2898 - - - - - 9400

8 2899 - - - - - 12000

9 2900 - - - - - 15200

10 2901 - - - - - 18400

11 2902 - - - - - 22400

12 2903 - - - - - 26000

13 2904 - - - - - 30400



14 2905 - - - - - 34800

15 2906 - - - - - 39400

16 2907 - - - - - 44600

17 2908 - - - - - 48600

18 2909 - - - - - 52800

19 2910 - - - - - 57800

20 2911 - - - - - 63000

21 2912 - - - - - 68400

22 2913 - - - - - 73400

23 2914 - - - - - 79000

24 2915 69200 - - - - 84800

25 2916 71200 - - - - 92200

26 2917 72600 - - - - 96800

27 2918 74600 - - - - 103400

28 2919 76000 81100 86200 - - 109400

29 2920 77400 82500 87600 - - 116000

30 2921 79000 84000 89000 94700 100400 122600

31 2922 80600 85500 90400 96100 101800 129800



2.2.7 Summary of Flood Regulation Procedure.

ThefloodregulationproceduresatHemavathy Damcanbesummarizedin the following 5

steps: ·

1 Observe the reservoir level at 1 hour intervals.

2 Determine thetotal outflowoccurringatall outlets(including river sluices, canals &

spillway)

3 Estimate the inflow by the method given in Para 2.2.6.2

4 Determinethe radial crest gate opening from the Para 2.2.6.3

5 Open all6 radial crest gates to the extentrequiredto dispose off the surplus flood

as per the procedure described in para 2.2.6.3

6 The procedure being followed in gate operation is as below.

a. The end gates should normally be opened first to prevent cross flow striking

against the guide walls and junctions.

b. At any time during the operation of different gates, the difference in gate opening

of any two consecutive gates should not exceed 50 cm.

c. After opening the end gates, the gates at the centre should be opened and other

gates should be opened in symmetrical manner starting from the centre towards

the end through gradual increase in the openings.

d. While closing the gates, the gate that was opened last should be closed first. The

procedure to be followed for closing the gates would generally be the reverse of

the procedure followed for opening the gates. Complete closure of the gates should

be accomplished by gradual lowering of the gates by 20 cm to 30 cm in the proper

sequence.

2.3 Operation of Radial Crest Gates of Hemavathy Dam

2.3.1 Brief Description.

Crest Gates· of Hemavathy Dam havebeen designed and errected by Tungabadra steel

products private Ltd., Karnataka with spillway crest level of 881.49 m and FRL of 890.63

m. The basic principal of thedesignis that thewaterpressureis transferredtopiersand

abutmentsthroughskinplates,stiffenershorizontalgirders,arms, trunion, tie flats and

anchor girders. The skin plates between bottom and tophorizontalgirdersisdesigned

assupportedonthegirders.The portion below the bottom horizontal girder up to sill

beam and above top horizontal girder and up to FRL is designed as cantilever. ·



2.3.2 Radial Crest Gates – Technical Data

1. The spillway Radial Gate consist of an upstream curved skin plate of varying thickness from

14 mm to 10 mm, stiffened by suitably spaced vertical ISMB stiffeners.

2. The sill beam, wall plates are provided with suitable anchorage for a rigid connection to the

spillway crest and the piers Suitable MS plates are welded on the wall plate to match with the

rubber seals. The sill beam embedded in the spillway crest are provided sealing surfaces of

mild steel to match with the rubber seal on the bottom of the gates.

3. The gate consists of structural steel frame formed by two (2) main horizontal girders

supported by radial arms attach end. These inclined radial arms in turn transmit the load to

trunnion brackets anchored and installed on the place provided besides the spillway piers.

The water load is transferred through girders to end arms and trunnion brackets, and then

finally transferred to pier concrete.

4. Gate Assembly

The skin plate of the gate consists of a 10 to 14-mm-thick stainless steel on the u/s side. The

skin plate is stiffened by radial shaped vertical stiffeners. which rests on horizontal girders.

The vertical stiffeners rest on horizontal girders. which are mounted on suitably braced in-

clined arms fixed to the trunnion assembly. The skin plate is supported on 2 main horizontal

girders which are in turn, supported on a frame of inclined arms. The water load is transferred

to pier concrete through Anchor beams welded to anchor girder embedded in pier concrete.

This force is taken by the trunnion tie connecting the two trunnion hub limbs.

5. Trunnion Assembly

The trunnion assembly consists of a single piece cast steel trunnion hub to which the arms

of the gates are rigidly connected to ensure full transfer of load. Stainless steel trunnion pins

with bush bearings pins connect trunnion hub to radial arms.

6. Seal Arrangement

The radial gate is seated at the bottom by contact of bottom edge of skin plate and Z- Type

rubber seals.



2.3.3 Salient Features.

2.3.4 Photographs of Electro-mechanical network of gates.

1.Downstream view of crest gate

Sl.

No. Feature Description

I. Type of gate Spillway radial Crest gate

ii. Size of Gate 10.66 m x 9.14 m

iii. No. of Gates 6 Nos (Gate 1 to 6)

iv. Clear width of opening 10.66 m

v. Operation Arrangement Electro-mechanical (rope-drum type)

vi. Gate position Indicator Mechanical Dial Indicator at Gate Location

vii. Crest level of spillway EL 881.49 M

viii. Sill level of Gate El 881.49 M

ix. Top of Gate El 890.63 M

x. FRL EL 890.63 M

xi. MWL EL.890.63 M



2.View showing the gate horizontal girder, end radial arms, trunnion hub & trunnion an-chorages etc.

3. Photo showing the control panel of the radial crest gate.



4. Photo showing the rope drums of operating system of river sluice gates.

5. Photo showing the control panel and other accessories of the river sluice gate.



6.Photo showing wire ropes & pulleys in the river sluice gate well.



7. Photo showing the rope-drums and machinery assembly of the canal sluice gate.



8. Photo showing the control panel of the canal sluice gate.

9.Photo showing wire ropes and pulleys in the canal gate well.

2.4 Operating Instructions

The Gates are operated by electro-mechanical system (rope-drum type). This system is

capable of fully opening or fully closing the gates holding them fully opened or in any



intermediate position, during either the opening or closing operation. The closing time and the

opening time is 10 minutes. The limit switches mounted on the panel board unit are set

to stop the hoist when the units reach the required opening. The gate opening indicator

dial gauge is fixed to the rope drum which gives the height of gate opening while raising

or lowering the gate.

2.4.3 Checklist Before Operation

The following steps are to be taken before operation of the gates to ensure these eight

critical functions are in good working condition.

Sequence Description Actions to be carried out

Step 1 Seal Clamp The seal clamp fixing should be such as to ensure that the side

seals are flexible enough

Step 2 Limit Switch

Limit Switches shall. be checked for satisfactory operation

(function) to stop the hoist when the gate reaches the required

opening position or closing position

Step 3 Nut& Bolts All nuts, bolts and screws shall be checked for wear, tear and

tightness

Step 4 Pins

Gate pin, connecting pin and all other pins should be in

proper position and ensure that the nuts and split pins are

tight and proper

Step 5 Trunnion Lu-

brication

To check and apply the high-pressure lubricating grease in

trunnion bushing from the hole provided in trunnion hub

Step 6 Control Panel

Control Panel shall be checked for its suitability for the pur-

pose envisaged. The check may include items such as weather

proofing, conducting wires, etc. In case of any contact chatter,

clean the magnet surface and try again. If the chattering

continues, check the coil voltage and replace the contact /

coil, if necessary

2.4.4 Electrically operated Hoisting Arrangements for Radial Crest Gates

The main component of electrically operated hoisting system for operation of the crest gates of

Hemavathy Dam spillway is the power-pack, mounted on the pier top of the spillway.



The electrical power pack consists of electrical and

electronic control for supply of power to the

pumps. The system which is called the control

panel is mounted on the shorter side of the motor

assembly. On the face of the control panel,

controls are provided for various operation of the

gate and also gauges indicating the power input and

output. There are ·also pilot lamps to

indicate the operation is in progress. The hoisting

system is provided with limit switches to cut off

power supply when the gate reaches the specified

position.

2.5 RESERVOIR LEVEL

The Reservoir levels are being recorded by

taking graph readings from the instrument

installed in the gauge room which com-

prises of rotating drum surrounded by

/fixed with graph sheet and an arm linking

one end to the stopclock and other end

which is having a round shaped notch

wheel to the hanged thread one end of

which carries lightweight floats in the wa-

ter surface and other end having plumb

bob. A pointed marker is fixed to the arm in between two ends.

As the variation occurs in the reservoir level the arm may move right or left side along with pointed

marker pen on the graph sheet fixed to the drum which depends upon the lowering or raising of

the reservoir level. The horizontal and vertical scales of the graph sheet may be read as 1mm =

4cms & 1mm = 20 minutes respectively.

2.5.3 RIVER OUTLET WORKS:

The system consists of electro-mechanical hoisting assembly, sluice gate chamber with service

platform and stilling basin.

View of Radial Crest Gate Oper-ating Platform on which control panel board & other mechanical devices have been installed

View of manual gauge recording equip-ment



2.6 DESCRIPTION

2.6.1.1 RIVER SLUICE GATES:

The Hemavathy dam is provided with 5 No’s of River Sluice Gates of size 2.44 m x 4.26 m and

Gantry Crane of 40 T capacity is provided for the operation of emergency gates.

2.6.1.2 HEAD REGULATOR:

Head Regulators at HLBC and HRBC with 5 No. and 4 No’s of irrigation sluice gates of size 2.44

M x 3.05 M respectively. The gantry crane of 25 T capacity is commissioned for operation of

emergency gates.

Details of length of canals, discharge and area contemplated for 3 major canals under

Hemavathy Dam is narrated below;

Hemavathy Left

Bank Canal

Hemavathy Right

Bank Canal

Hemavathy Right Bank

High Level Canal (fore-

shore)

a) Length

( Km) 212 91 97

Downstream View of Head regulator gate of HLBC sluice vents



2.6.2 Operation:

2.6.2.1 General

Water is being released to the irrigation canals when there is a sufficient storage in the

reservoir according to the instructions and proceedings of the ICC meeting headed by

the concerned district in charge minister of Karnataka Govt.,

2.6.2.2 Restrictions:

Hemavathy river is main tributary of Cauvery river having its origin in the Western Ghats of

Chikamaglur district in Karnataka & flows for a length of 192 kms before joining the back waters

of Krishnarajasagar dam. Hemavathy reservoir designed for a total storage capacity of 37.103 TMC

and live storage 4.372 TMC. The Hemavathy project schemed to irrigate 6.55 lakh acres in flow

irrigation & 45,756 acres from the lift irrigation schemes in foreshore and in the downstream of

the reservoir. This project comes under the Cauvery Water Dispute Tribunal which allocates and

enforces to use 43.67 TMC of water per year.

2.6.2.3 Mechanical:

River Sluice Gates and Irrigation Sluice Gates are operated by electro-mechanical system and in-

case of power failure, these gates can be operated by generators. The discharge calibration tables

for discharge through river sluice and canal sluice gates have been made on the basis of the formula

Q= 0.85*sqrt (2gH)*A.

Where :

A = Area of sluice gate opening.

G = Acceleration due to gravity.

H = Height measured from water level in the reservoir to the centre of the opening.

Table 17- Calibration chart for discharge through River Sluice gate of Hemavathy Dam.

Cill level of the gate = 2805ft

b) Capacity

( cumecs) 113.26 9.34 25.48

c) Area

irrigated / contem-

plated in hectares

78915 8094 22663



Size of the gate = 8x14ft

Sl No. Reservoir

Level Gate open-ing in feet

Discharge in cusecs

1 2922 1 588.76

2 2922 2 1174.99

3 2922 3 1758.69

4 2922 4 2339.84

5 2922 5 2918.43

6 2922 6 3494.46

7 2922 7 4067.92

8 2922 8 4638.80

9 2922 9 5207.09

10 2922 10 5772.79

11 2922 11 6335.87

12 2922 12 6896.35

13 2922 13 7454.20

14 2922 14 8009.42

Table 18- Calibration chart for discharge through canal Sluice gates of Hemavathy Dam.

Cill level of the gate = 2845ft

Size of the gate = 8x10ft

Sl No. Reservoir

Level Gate open-

ing in ft. Discharge in cusecs

1 2922 1 477.10

2 2922 2 951.07

3 2922 3 1421.91

4 2922 4 1889.59

5 2922 5 2354.10

6 2922 6 2815.42

7 2922 7 3273.54

8 2922 8 3728.45

9 2922 9 4180.11

10 2922 10 4628.53

2.6.3 References:

2.6.3.1 Drawings:

The relevant drawings are enclosed in ANNEXURE - I



2.7 Access Roads

2.7.1 Description

(Type of road, length, bridges, maintaining agency, etc.)

Type of road: Asphalt road.

Length: 3.675 kmtr

Bridges: Nil

Maintaining agency: Maintaining departmentally.

2.7.2 Condition:

General: Road is in good condition

2.7.3 Deficiencies and problems Nil

2.8 Record Keeping

Operating a dam includes keeping accurate records of items pertaining to project operation. These

include but not limited to the following:-

1. Rainfall and Reservoir Levels – On daily basis during non-monsoon and on hourly basis dur-

ing monsoon. (see Chapters 2, 3 and 4 for detailed instructions and procedures)

2. Release through outlet/sluices on daily basis for irrigation, water supply, hydropower etc.

3. Outflows through spillway during monsoon on hourly basis.

4. Records of drawdown with reservoir levels, quantity of water released, drawdown rates, rea-

son for drawdown.

5. Other Procedures – Maintain a complete record of all operating procedures for gates, sluices.



CHAPTER 3 - PROJECT INSPECTIONS

The current practice of Inspection at Hemavathy dam envisages the Subdivision Officers to car-

ryout pre-monsoon and post-monsoon inspections. The checklist proforma included in this chap-

ter is currently in use at Hemavathy dam.

Detailed description on project inspections is available in the Guideline for Safety Inspection of

dams (Doc No. CDSO_GUD_DS_07_ v1.0), CWC 2018 (https://damsafety.in/ecm-in-

cludes/PDFs/Guidelines_for_Safety_Inspection_of_Dams.pdf). However, an overview of the

various types of inspections to be carried out at Hemavathy dam is given below. Note that for

uploading Inspection Data into DHARMA, the Inspection Instructions & Forms given in the

abovementioned Guideline for Safety Inspection of Dams must be used (see Appendix 5)). An

effective inspection program is essential toidentify problems and to keep Hemavathy Dam in a

good and healthy condition. This Chapter provides guidance on carrying out other inspections.

3.1 Types of Inspections

Four different types of dam safety inspections are being carried out at Hemavathy Dam. These

include, but not limited, to the following:

1. Comprehensive evaluation inspections

2. Scheduled inspections (Pre & Post monsoon inspections & other scheduled inspections)

3. Special (unscheduled) inspections

4. Informal inspections

The frequency of each type of inspection depends on the condition of the dam and State DSO

regulations, etc.

Typical inspection elements and the detail of the safety inspections are provided below. More

detailed descriptions are given in the ‘Guideline for Safety Inspection of Dams’ (CWC 2018). A checklist

has been modified from the guideline to fit Hemavathy Dam requirements and is found in

Appendix 5.This comphrehensive checklist allows for recording the status of each item being

inspected and the overall condition of the equipment along with any consequential risks the

condition may have on the health of the dam.

https://damsafety.in/ecm-includes/PDFs/Guidelines_for_Safety_Inspection_of_Dams.pdf

https://damsafety.in/ecm-includes/PDFs/Guidelines_for_Safety_Inspection_of_Dams.pdf



3.1.1 Comprehensive Evaluation Inspections

For comprehensive dam safety evaluation, an independent panel of experts known as Dam Safety

Review Panel (DSRP) needs to be constituted for determining the condition of the dam and ap-

purtenant works. The panel will undertake evaluation of the dam once in 10 years or on occurrence

of any extreme Electrological or seismic event or any unusual condition of the dam or in the res-

ervoir rim. The terms of reference of the comprehensive dam safety evaluation shall include but

not be limited to;

1. General assessment of Electrologic and hydraulic conditions, review of design flood, flood

routing for revised design flood and mitigation measures.

• Review and analysis of available data of dam design including seismic safety, construc-

tion, operation, maintenance and performance of dam structure and appurtenant

works.

• Evaluation of procedures for operation, maintenance and inspection of dam and to

suggest improvements / modifications.

• Evaluation of any possible hazardous threat to the dam structure such as dam abutment

slope stability failure or slope failures along the reservoir periphery.

A comprehensive evaluation inspection of Hemavathy Dam consists of five major parts:

2. Review of project records (i.e. study of all design / construction records/drawings, history of

the dam’s performance, past inspection notes/reports, notes on distress observed/ any reha-

bilitation measures undertaken earlier, instrumentation data including interpretation.

3. Inspection of the dam and its appurtenant works.

4. To review the results and reports of additional field investigations & laboratory testing if re-

quired.

5. Review of design studies e.g. review of design flood, checking of the adequacy of spillway

capacity, freeboard requirements, dam stability, any special study as required.

6. Preparation of a detailed report of the inspection.

3.1.2 Scheduled Inspections

Scheduled inspections shall consist of Pre-monsoon & Post-monsoon inspection and

any other inspections carried out by the State Dam Safety Organisation / any Expert

panels constituted by the dam owner.



These inspections are performed to gather information on the current condition of the

dam and its appurtenant works. This information is then used to establish needed repairs

and repair schedules, and to assess the safety and operational adequacy of the dam.

Scheduled inspections are also performed to evaluate previous repairs.

The purpose of scheduled inspections is to keep the dam and its appurtenant structures

in good operating condition and to maintain a safe structure. As such, these inspections

and timely maintenance will minimize long-term costs and will extend the life of the

dam. Scheduled inspections are performed more frequently than comprehensive

evaluation inspections to detect at an early stage of any developments that may be

detrimental to the dam. These inspections involve assessing operational capability as well

as structural stability and detection of any problems and to correct them before the

conditions worsen. The field examinations should be made by the personnel assigned

responsibility for monitoring the safety of the dam. If the dam or appurtenant works

have instrumentation, the individual responsibilility for monitoring should analyze

measurements as they are received and include an evaluation of that data. Dam

Inspection Report or an inspection brief should be prepared following the field visit

(Dam Inspection Report is recommended).

Scheduled inspections include the following four components as a minimum:

• File review of past inspection reports, monitoring data, photographs,

maintenance records, or other pertinent data as may be required;

• Visual inspection of the dam and its appurtenant works;

• Preparation of a report or inspection brief, with relevant documentation and

photographs. The report should be filed in the dam owner’s project files.

3.1.3 Special (Unscheduled) Inspections

Special inspections may need to be performed to resolve specific concerns or conditions

at the site on an unscheduled basis. Special inspections are not regularly scheduled

activities, but are usually made before or immediately after the dam or appurtenant works

have been subjected to unusual events or conditions, such as an unusually high flood or

a significant earthquake. These inspections are to be carried out after an initial

assessment based on informal inspection carried out by project personnel reveals that

the dam safety related concerns like cracking in the dam, damages, erosion/ scour,

undermining/ piping/ sink holes/ liquefaction or any such undesirable feature. A special

inspection may also be performed during an emergency, such as an impending dam

breach, to evaluate specific areas or concerns. They are also made when the ongoing

surveillance program identifies a condition or a trend that appears to warrant a special

evaluation. Special inspections should focus on those dam components that are affected



by the unusual event and should include at least three elements: 1) review of relevant

files or data, 2) visual inspection, and 3) report preparation.

More detailed site investigations / studies may be required (such as drilling, surveys, or

seepage flow estimates) if the special inspection reveals the need for the same.

Photographic documentation is to be included as part of the inspection.

Japan Water Agency (JWA) has developed a system of carrying out inspections after an

earthquake event for Ichari Dam, Uttarakhand. For details refer “Inspection Manual for

Dam Field Engineers after Seismic Events, Ichari Dam, Uttarakhand

(CDSO_GUD_DS_0_v1.0, September 2017). The manual is available at the following

link: https://damsafety.in/ecm-

includes/PDFs/Inspection_Manual_for_Dam_Field_Engineers_After_Seismic_Event

s.pdf.

3.1.4 Informal Inspections

The last type of inspection, an informal inspection, is a continuing effort by on-site

personnel (dam owners/operators and maintenance personnel) performed during their

routine duties. Informal inspections are critical to the proper operation and maintenance

of the dam. They consist of frequent observations of the general appearance and

functioning of the dam and appurtenant structures.

Operators, maintenance crews, or other staff who are posted at Hemavathy dam site

conduct informal inspections. These people are the “first-line of defense” in assuring

safe dam conditions, and it is their responsibility to be familiar with all aspects of the

dam. Their vigilance in walking the dam, checking the operating equipment, and noting

changes in conditions may prevent serious mishaps or even dam failures.

Informal inspections are important and are performed at every available opportunity.

These inspections may only cover one or two dam components as the occasion presents

itself, or they may cover the entire dam and its appurtenant structures. The informal

inspections are not as detailedas comprehensive evaluation, scheduled, and special

inspections and will only require that a formal report is submitted to the dam owner’s

project files if a condition is detected that might endanger the dam.Report is to be

submitted detailing the condition discovered along with photographs, time, reservoir

water level (RWL), etc.

3.1.5 Pre- and Post-Monsoon Checklist and Example of Report Proformas

Detailed checklists are required to ensure the health of the dam continues to operates in satisfactory

and safe condition. Details of the inspection must be in alignment with the DHARMA approved

checklist as shown below.



PRO-FORMA FOR PERIODICAL INSPECTION OF

LARGE DAMS

GENERAL Date of Inspection: ________________

Sl.

No. Item of Inspection Remarks

1 1a 1b 2 3

1. Name of project Hemavathy Reservoir Project

2. Purpose of Project Irrigation

3. Name of Dam HEMAVATHY DAM.

4. Year of Completion 1979-80

5. First filling (years / levels) 1977 Rl-879.17 m

6. Benefits accrued:

a) Irrigation Irrigation

b) Water Supply Water Supply

c) Power Power

d) Other benefits Nil

7. Important Controlling Levels (in meters)

a) Top of dam 894.59 M.

b) Maximum Water Level 890.63 M.

c) Full Reservoir Level 890.63M

d) Sill level of Irrigation sluices 867.16 M.

e) Sill level of scouring sluices 854.97M.

f) Spillway crest level 881.49 M.

g) Minimum draw down level 872.34 M.

h) Lowest river bed level 850.09 M.

i) Deepest foundation level 836.07 M.



8. Important Salient Features

a) Dead Storage Capacity 123.80 M.Cum (at MDDL, 872.34

M)

b) Area of foreshore at F.R. L 85.02 Sq.Km.

c)

Design flood adopted

(PMF / SPF / Any other)

Give relevant magnitude

PMF-10,934 Cumecs.

d) Design spillway discharge capacity

and type of spillway

Ogee type Spillway 3624.52 Cu-

mecs.

8 a) Type, number and size of spillway

gates.

RADIAL TYPE, 6 numbers of

10.66 m X 9.14 m size.

b) Location, sill level and capacity of low

level outlets and scouring sluices.

River Sluice, sill level-854.97 m,5

Nos – 2.44 m X 4.26 msize &ca-

pacity 1115.67 cumecs.

c) Height of the dam in meters.

i) Above deepest foundation 58.52 m

ii) Above lowest river bed 44.50 m

d) Gross storages capacity in million cubic meters

i) At F.R.L. 1050.63 MCM (37.103TMC)

ii) At M.W.L 1050.63 MCM (37.103 TMC)

e) Length of the dam (at crest) in meters. 3675 Mtr.

9. Name and designation of the inspecting of-

ficer

1) ChiefEngineer, CNNL,Hema-

vathy Project Zone , Gorur

2)SuperintendingEngineer,

CNNL, Hemavathy Project Cir-

cle, Gorur.

3). E. E. HemavathyDam Divi-

sion, Gorur.



10. Date of inspection and the corresponding

reservoir water level.

1) Chief Engineer, CNNL,

Hemavathy Project Zone , Gorur

Date of Inspection :

Reservoir Level:M

2) Superintending Engineer, CNNL,Hema-

vathy Project Circle , Gorur


Reservoir Level:M

3) Executive Engineer,

Hemavathy Dam Division, Gorur.


Reservoir Level:M

11. Maximum and minimum water levels

reached during the last season with dates

Maximum: M__________

Dt:___________________

Minimum: M__________

Dt:___________________

12. Maximum overflow during preceding mon-

soon with dates.

Max. outflow :cusecs __________

Dt:___________________:.

13. History of past distress, if any, and brief de-

tails of remedial measures carried out. No such events occured.

14.

Does the officer-in-charge of the operation

and maintenance of dam possess all the rec-

ords as given in the Annexure-I.

15. When and by whom the dam was inspected

immediately preceding this inspection? -----------

16.

Are the items pointed out during the last in-

spection properly attended to?

(If not state deficiencies yet to be corrected).

-----------



REVISED PRO-FORMAT

FOR

HEALTH STATUSREPORT OF LARGE DAMS

(Keeping in view CWC letter No. 627-56 dt. 28-08-2002)

Sl.

No.

Items of the

“Health Status Report” Reply

1 Name of Dam Hemavathy Dam

2 Sl. No. in the National Register of Large

Dam

Project Identification Code PIC

KA06HH0117

3 Dam features

a) Year of Completion 1979-80

b)

Location

i) Longitude 76° 03' 00˝ E

ii) Latitude 12° 45' 00’’ N

c) Height of Dam 58.52 Mtr. above the lowest founda-

tion

d) Gross Capacity

(Gated/Un gated)

37.103 TMC ft.(1.05 TMCUM)

Gated

e) Whether the Dam is provided with

Drainage Gallery or not.

Provided with Drainage Gallery of size

1.52 m X 2.28 m

4 Main Component of Dam

Type of Dam: Composite Dam:

Spillway: Gated spillway with 6 Nos of

Radial Crest gates of size 10.66m X

9.14m.



Length of concrete spillway dam-

94mtr.

Length of Masonry non-overflow

Dam- 272 mtr.

Length of earthen Dam: 3309 M.

5 Date of Inspection

6 Inspecting Officer Chief Engineer, CNNL Hemavathy

Project Zone, Gorur.

7 Observations/Significant Deficiencies Noticed

I Inadequate Spillway.

II Inadequate free-board

III Cracks in Masonry / Concrete

/Earth Dam

a) Masonry/concrete dams and

b) Structural cracking in earth

dams

IV Inadequate

a) Flood forecasting system

b) Flood warning system

c) Communication

V Excessive seepage through,

a) Drainage holes



b) Porous pipes

c) Downstream face of dam

d) Downstream area etc.

e) Development of high uplift

pressure

VI Excessive leaching

VII Choking of porous drains.

VIII Choking of drainage holes

IX Mal-operation of gates

X Non-availability of standby/ alter-

native source of power

XI Structural Review indicating

tension on the upstream face of dam

XII Non-availability of Emergency Ac-

tion Plan.

8 Performance of Dam

Based on Instruments installed in the dam

(Water Level Recorder, V-notch, etc.,)

Of Meteorological Instruments installed in

the catchment area and reservoirs of Dams.

Is the hydraulic performance in agreement

with the results of model studies?

Any other issue / issues pertaining to perfor-

mance of dam which the Engineer-in-Chief



/ Chief Engineer in-charge of dam desires to

include.

9 Remedial Measures Suggested.

10 Remarks

11 Action Taken Report.

Assistant Exe Engineer , Executive Engineer

Hemavathy Dam in-charge of dam

Sub Division,

Superintending Engineer

in-charge of dam.

Certified that the Health Status Report of HEMAVATHY DAM is furnished after a thorough review of the

same by the technical wing of the zone (this has reference to para 18.3.5 of the Proceedings of 18th meeting of

SLDSC).

Engineer-in-Chief / Chief Engineer

in-charge of dam.



APPENDIX-1

Performance of Dam Instruments

Sl.

No.

Name of Dam

with location

Name of Instrument No. of Instru-

ments

Performance Status of data Analysis Remarks

1 2 3 4 5 6 7

Separate Sheets Enclosed.

(Vide Annexure-1)

Asst Exe Engr,Executive Engineer Superintending Engineer Engineer-in-Chief / Chief Engineer

in-charge of dam.in-charge of dam. in-charge of dam in-charge of dam.



APPENDIX-2

Performance of MeteorologicalInstruments pertaining to Large Dams in Karnataka

Sl.

No.

Name of Dam with

location Name of Instrument

No. of In-

struments Performance

Status of data

Analysis Remarks

1 2 3 4 5 6 7

Details to be furnished by WRDO Bangalore.

Engineer-in-Chief,

Water Resources Development Organization, Bangalore.



APPENDIX-3

Categorization of Deficiencies

(Keeping in view CWC letter No. 627-56 dt. 28-08-2002)

Category No.* Criteria for categorization

Category No. (1) Dams with major deficiency which may lead to dam failure

Category No. (2) Dams with rectifiable deficiency which needs immediate attention.

Category No. (3) Dams with minor / no deficiencies has been noticed.

* Category Number is to be furnished in the ‘remarks’ column of the

Health Status Report.



CHAPTER 4 - PROJECT MAINTENANCE

A good maintenance program protects Hemavathy Dam against accelerating

deterioration, prolongs its life, and greatly reduce the chance of failure. Nearly all the

components of Hemavathy Dam and its materials are susceptible to damage and

deterioration if not well maintained. Moreover, the cost of a proper maintenance

program is small compared to the costs of major repairs, loss of life and property and

litigation. Preventative maintenance not only protects the dam and its owner but the

public as well. If maintenance of a dam is neglected the consequences and costs will be

multiple.

Preventive maintenance assures that a dam and reservoir are in good working condition

and prevents more harmful conditions from developing. Individual maintenance tasks

are noted with a description of the area where the maintenance is to be performed, the

schedule for performing the tasks, and reporting procedures. Typical routine

maintenance tasks performed includes removing grass, removing vegetation, bushes and

trees, removing litter and other debris, re-grading the crest and/or access roads,

repairing fencing to keep livestock off the dam, etc. Other maintenance works that need

to be performed on the embankment includes restoration of embankment to its design

section, seepage problems, erosion, displaced riprap, cracking in embankment etc. In

concrete / masonry dams there may be issues like cracking and disintegration in

concrete, choking of drainage holes in dam body/ foundation, damages to spillway

glacis/piers/energy dissipaters due to abrasion/ cavitation/unsymmetrical flows,

damages to pointing on upstream & downstream faces of masonry dams, heavy

seepages through some drains in foundation/inspection galleries etc.

A basic maintenance program has been developed primarily based on systematic and

frequent inspections.

4.1 Maintenance Priorities

For Hemavathy Dam, maintenance activities require to be prioritized as immediate

maintenance or preventative maintenance.

4.1.1 Immediate Maintenance

The following conditions are critical and call for immediate attention & reservoir

lowering, if warranted. These conditions may include, but are not limited to:



• The dam is about to be overtopped or being overtopped during high flood.

• The dam is about to be breached by erosion, slope failure etc.

• The dam showing signs of piping or internal erosion indicated by increasingly

cloudy seepage or other symptoms.

• The spillway being blocked or with some inoperable gates.

• Evidence of excessive seepage appearing anywhere on the dam site ,e.g., the

Embankment becomes saturated, defective water stops, etc., and seepage exiting

on the downstream face is increasing in volume.

Although the remedy for some critical problems may be obvious (such as clearing a blocked spill-

way or repairing the spillway gates so that they are in working condition), the problems listed above

generally demand the services of experienced engineers/expert panels familiar with the design,

construction and maintenance of dams. The emergency action plan (EAP) should be activated

when any of the above conditions are noted. Note also that the “blue” conditions of the EAP are

also applicable during controlled release of floods through the spillway.

4.1.2 Preventive Maintenance

This can be further classified as Condition based Maintenance and Routine Maintenance.

4.1.2.1 Condition Based Maintenance

The following maintenance should be completed as soon as possible after the defective condition

is noted. These include but are not limited to:

✓ Remove all vegetation and bushes from the dam and restoring any eroded areas and to

establish a good grass cover.

✓ Fill animal burrows.

✓ Restore and reseed eroded areas and gullies on embankment.

✓ Repair of defective gates, valves, and other Electro-mechanical equipment.

✓ Repair any concrete or metal components that have deteriorated.

✓ Cleaning of the choked drainage holes in the dam body/ foundations in concrete / ma-

sonry dams.

✓ Repair any damages on spillway glacis, piers, energy dissipaters, training/divide walls,

downstream areas etc.



✓ Repairs on the upstream face of masonry dams, in case the pointing is damaged, due to

which there is increased seepage.

✓ Controlling any heavy seepage in the foundation/ inspection galleries in Concrete/Ma-

sonry dams from drainage holes.

✓ Repairs of any cracks/cavities/joints in concrete/masonry dams/structures.

However many of these works will require the services of experienced engineers/expert panels.

4.1.2.2 Routine Maintenance

Several tasks should be performed on a continuous basis. These include but are not limited to the

following:

✓ Routine moving, restore and reseed eroded areas and gullies on downstream face of the

embankment and general maintenance.

✓ Maintenance and treatment of any cracks/joints/ cavities in Concrete/Masonry dams and

spillways based on the recommendations of experienced engineers / expert panels.

✓ Observation of any springs or seepage areas, comparing quantity and quality (clarity) with

prior observations in the embankment.

✓ Monitoring of downstream development which could have an impact on the dam and its

hazard category.

✓ Maintenance of Electrical &Electro-Mechanical equipment and systemse. g. Servicing of

spillway gates, gantry crane, sluice gates& stand by generator.

✓ Maintaining proper lighting at dam top, galleries, etc.

✓ Monitoring of seepage in galleries.

✓ Monitoring/ cleaning & removal of leached deposits in porous concrete / formed drains

in dam body and foundation drainage holes.

✓ Maintenance of all dam roads & access roads.

✓ Operation of electrical and mechanical equipment and systems including exercising gates

& valves.

✓ To keep the gate slots clear of silt/debris.

✓ Maintenance/testing of monitoring equipment (instruments) and safety alarms.

✓ Testing of security equipment.

✓ Testing of communication equipment.

✓ Any other maintenance considered necessary.



4.2 Procedures for Routine Maintenance

The O&M Manual includes detailed instructions and schedules for performing periodic mainte-

nance works at the site. This include maintenance of the dam, the appurtenant works, and the

reservoir areas. Methodology / Specifications for carrying out maintenance works of general &

recurring nature should be included in the Manual.

Dam repairs are scheduled based on severity of the problem, available resources, and weather

conditions. For example, if a severe settlement problem (more than envisaged in designs) or crack-

ing is detected on the crest of the dam, it should have a high priority since further degradation

could lead to dam breaching. The causes of all major issues / problems should be identified and

evaluated by experienced engineers/ Expert Panels so that appropriate remedial measures can be

finalized. Correcting minor/ rill erosion on the downstream slope could be assigned a low priority

since it is not a dam safety concern. This type of repair will also be weather dependent, since grass

can only be planted during specific times of the year, and the embankment should be dry so that

more damage is not inflicted to the embankment slopes.

4.2.1 Earthwork

The surfaces of an earthen dam may deteriorate due to several reasons. For example, wave action

may cut into the upstream slope, vehicles may cause ruts in the crest or slopes, trails left by live-

stock can result in erosion, or runoff waters may leave erosion gullies on the downstream slope.

Other special problems, such as shrinkage cracks or rodent damage, may also occur. Damage of

this nature must be repaired constantly.

The maintenance procedures described here are effective in repairing minor earthwork problems.

However, this section is not intended to be a technical guide, and the methods discussed should

not be used to solve serious problems. Conditions such as embankment slides, structural cracking,



and sinkholes threaten the immediate safety of a dam and require immediate repair under the

directions of experienced engineers/Expert panels.

The material selected for repairing embankments should be free from vegetation, organic materi-

als, trash, and large rocks.

If flow-resistant portions such as the core of an embankment dam are being repaired, materials

that are high in clay or silt content should be used. If the area is to be free draining or highly

permeable (such as pervious shell of an embankment dam) the material should have a higher per-

centage of sand and gravel. It is usually satisfactory to replace or repair damaged areas with soils

like those originally in place.

An important soil property affecting compaction is moisture content. Soils that are too dry or too

wet do not compact well. One may test repair material by squeezing it into a tight ball. If the

sample keeps its shape without cracking and falling apart (which means it is too dry), and without

depositing excess water onto the hand (which means it is too wet), the moisture content is near

the proper level.

View of embankment & rock toe at the junction of masonry body

wall & earthen embankment



Before placement of earth, the repair area needs to be prepared by removing all inappropriate

material. All vegetation, such as bushes, roots, and tree stumps, along with any large rocks or trash

need to be removed. Also, unsuitable earth, such as organic or loose soils, should be removed, so

that the work surface consists of exposed, firm, clean embankment material.

Following cleanup, shape and dress the affected area so that the new fill can be placed and com-

pacted in horizontal lifts to the level specified in the technical specifications. Also it must be

properly keyed (benched) with the existing material for which proper construction practices are

carried out to “knit” the new fill in to the existing soils to ensure proper bonding. This can be

accomplished by using the following simple procedures

1. Scarify the existing soil layer

2. Place new moisturized soils in loose layers up to 20 centimeters thick

3. Compact to required density at optimum moisture content (OMC)

4. Scarify compacted layer 10 centimeters

5. Moisturize the layer before placement of soils

6. Compact

7. Continue process until lines and grades are accomplished. Overbuild can be trimmed back

to design lines and grades

8. Seed of turf the fill to minimize erosion processes

9. Water routinely to ensure turf root system is fully developed.

Erosion is one of the most common maintenance problems at embankment structures. Erosion is

a natural process and its continuous forces will eventually wear down almost any surface or struc-

ture. Periodic and prompt maintenance is essential to prevent continuous deterioration and possi-

ble failure.Turfing, free from weeds and deleterious materials, is an effective means of preventing

erosion. Rills and gullies should be filled with suitable soil, compacted, and then seeded or turfed

as necessary. Large eroded gullies can be slowed by stacking bales of hay or straw across the gully

until permanent repairs can be made.

Erosion is also common at the point where an embankment and the concrete walls of a spillway

or other structure meet. Poor compaction adjacent to such walls during construction and later

settlement can result in an area along the wall that is lower than the grade of the embankment.

People often walk along these walls, wearing down the vegetative cover. Workable solutions in-

clude re-grading the area so that it slopes away from the wall, adding more resistant surface



protection, or constructing steps. Steps can be provided / constructed at regular intervals along

the length of the dam for going from downstream toe to the dam top. All vehicular traffic, except

for maintenance, should be restricted from the dam.

Paths due to pedestrian, livestock, or vehicular traffic (two and four-wheeled) are a problem on

many embankments. If a path has become established, vegetation will not provide adequate pro-

tection and more durable cover will be required unless traffic is eliminated. Stones may be used

effectively to cover such footpaths.

Runoff often concentrates along embankment slopes where the hinge point on the crest is lower

than the surrounding crest and runoff ponds in these low areas. The concentrated runoff flows

downs the slope cutting the soils and forming rills and gullies resulting in loss of design lines and

grades and affecting stability of the structure.

Upstream Riprap

The upstream face is

protected against wave

erosion. Rip-rap is pro-

vided for the purpose

with filter layers below.

Nonetheless, erosion can

still occur in existing

riprap. Water running

down the slope under

the riprap can erode the

finer filter materials un-

der the riprap and soils

leaving voids and loss of

grade. Wave runup will

also undermine the filter layer especially along the full reservoir level and over time wash out finer

material. This can be checked through observance of linear embankment settlement. Sections of

riprap that have slumped downward are often signs of this kind of erosion. When erosion occurs

on the upstream slope of a dam, repairs should be made as soon as possible. Repairs can be made

following the same design details as provided in the embankment section. proper preparation of

the surfaces of the existing embankment as described in the earlier paragraph for placement and

View of Rehabilitated upstream Riprap



compaction of embankment. Please refer to IS 8237- Code of practice for protection of Slopes for Reservoir

Embankments is recommended to be reviewed and followed for carrying out this repair work.

Controlling Vegetation

Keep the entire dam clear of unwanted vegetation such as bushes or trees. Excessive growth of

which may cause several problems:

• It can obscure the surface of an embankment and not allow proper inspection of the dam.

• Large trees can be uprooted by high wind or erosion and leave large voids that can lead to

breaching of the dam.

• Some root systems can decay and root creating passage ways for water, leading to piping

erosion.

• Growing root systems can lift concrete slabs or structures.

• Rodent habitats can develop undetected.

All bushes/trees should be as far as possible removed by root to prevent regrowth. The resulting

voids must be backfilled with suitable, well-compacted soils. It is recommended to remove the

plants/vegetation at their early stage to prevent or minimize their growing into big trees/bushes,

etc. In cases where trees and bushes cannot be removed, the root systems should be treated with

environmentally-friendly herbicides (properly selected and applied) to retard further growth. Con-

cerned Government Agencies must be consulted for selection of appropriate herbicides & their

use for control of vegetation on dam structures or any water bodies.

Controlling Animal Damage

Livestock are not allowed to graze on the embankment section of the dam. When soil is wet,

livestock can damage vegetation and disrupt the uniformity of the surface. Moreover, livestock

tend to walk in established paths and thus can promote erosion.

The burrows and tunnels of burrowing animals (beaver, muskrat, groundhogs and others) weaken

earthen embankments and serve as pathways for seepage from the reservoir. Large burrows found

on the embankment should be filled by mud packing. This method involves placing vent pipe in a

vertical position over the entrance of the den. Making sure that the pipe connection to the den

does not leak, the mud-pack mixture is poured into the pipe until the burrow and pipe are filled

with the soil-water mixture. The pipe is removed and more dry earth is tamped into the entrance.

As per some US publications, the mud pack is generally made by adding water to 90% earth &

10% cement mixture until a slurry or thin cement consistency is attained. For bigger holes,



bentonite coated stones can also be used. All entrances should be plugged with well-compacted

earth and grassy vegetation re-established. Dens should be eliminated without delay. Different

repair measures will be necessary if a dam has been damaged by extensive small or large rodent

tunneling activity. The area around the entrance can be excavated and then backfilled with imper-

vious material. This will plug the passage entrance to prevent water entry and saturation of the

embankment.

Controlling Ants and Termites (White Ants)

Ants and termites have become one of the most serious pests for Embankment dams. They both

need water to survive and have been found on most of the embankment dams in India. These

insects can create problems in the dam itself and with any of its electrical components.

In some habitats, ants and termites can move as much or more soil as earthworms, thereby reduc-

ing soil compaction. Nest galleries can penetrate in a V-shaped pattern below the nest, penetrating

as much as more than one meter deep in the soil. These galleries can create pathways for surface

water to penetrate in the dam, resulting in internal erosion and collapse of the surface.

Ants and termites left undisturbed can build mounds that can become quite large. These can create

problems for mowing. However, frequent mowing can induce the colonies to migrate to neigh-

boring, undisturbed areas.

There are many options for managing ants and termites. Use only pesticides labeled as suitable for

the location you want to treat. Make every effort

to avoid contaminating water with pesticides and

ensure.

Controlling Damage from Vehicular Traffic

As mentioned earlier, vehicles driving across an

embankment dam can create ruts in the crest if it

is not surfaced with roadway material and some-

times even when sealed with flexible pavement,

especially when the embankment is saturated and

overweight trucks use the road. The ruts can then

collect water and cause saturation and softening

of the dam. Other ruts may be formed by tractors

or other off-road vehicles such as motorbikes are allowed to drive up and down the embankment

face; these can direct runoff resulting in severe erosion.

Hemavathy Dam Crest



Vehicles, except for maintenance, are restricted on the dam top and kept out by fences or barri-

cades. Any ruts should be repaired as soon as possible.

4.2.2 Masonry / Concrete Dams & Spillways

Various issues/problems that may require maintenance/repairs on the Hemavathy Concrete/Ma-

sonry Dam and Spillway include but not limited to:

• Damages on spillway glacis, spillway piers, training/divide walls, energy dissipaters, down-

stream areas (probable causes are cavitation, abrasion, un-symmetrical flows, unfavorable

down-stream conditions)

• Vegetation growth in unattended areas such as spillway, spillway channel, etc.

• Seepage in the galleries and on the downstream face of the dam.

• Cleaning and removal of leached deposits from choked porous and foundation drains.

• Repair to upstream face of masonry dams in case the pointing is damaged, leading to in-

creased seepage.

• Ensuring safeaccess to and within the gallery, lighting is also required as well as all outside

areas during the evening hours.

• Ensuring the dam is behaving as de-

signed based on instrumentation pro-

grams.

• Periodic maintenance should be per-

formed for all concrete surfaces

which are approachable to repair de-

teriorated areas.

For remedial measures of problems of spe-

cial nature advice of experienced engineers

/Panel of Experts needs to be obtained

4.2.3 River Sluices

The sluices should be inspected thoroughly once in a year for any damages such as cracks and

seepage. As regards to Electro-mechanical works, reference may be referred to the appropriate

paragraphs in this chapter.

Hemavathy Dam U/s face of Masonry section treated with PICC under DRIP Project



4.2.4 Gates & Electro-mechanical Equipment

The safe and satisfactory operation of Hemavathy Dam depends on proper operation of its Gates

& Electro-mechanical Equipment. Maintaining spillway gates in working condition is critical for

dam safety and is to be assigned the highest priority.

If routine inspection of the Electro-Mechanical Equipment shows the need for maintenance, the

work should be completed as soon as possible. The simplest procedure to ensure smooth opera-

tion of gates is to operate them through their full range at least once, and preferably twice annually

(before monsoon & after monsoon keeping a gap of at least six months). Because operating gates

under full reservoir pressure can result in large discharges, exercising of gates should preferably be

carried out during dry conditions or lean times of the year.

Commonly used Gates including their inspection / maintenance requirements are discussed below.

The aspects to be inspected and maintained periodically for ensuring proper operation of these

gates are as under:

i) The gate slot and bottom platform/sill beam should be cleaned periodically. Scales

formed over the embedded parts should be removed. Second-stage concrete should be

checked for any development of cracks / leakages and repairs should be attended to immedi-

ately.

ii) The gate leaf should be thoroughly cleaned and repainted as and when necessary ac-

cording to the procedure or guidelines- indicated in IS: 14177 or as per the recommendations

of the paint manufacturer. All drain holes provided in the gate assembly should be cleaned.

iii) Rubber seals should be smoothed, if required, for proper alignment. All nuts and bolts

fixing the seal to the gate should be tightened uniformly to required torques. Seals, if found

damaged or found leaking excessively should be adjusted, repaired or replaced as considered

necessary.

iv) The wheel shall be rotated to check their free movement. Gate roller bearings and

guide roller bushes should be properly lubricated. Whenever necessary these should be opened

for rectifications of defects, cleaning and lubrication and should thereafter be refitted. These

may be replaced if repairs are not possible.

v)The gate leaf should be lubricated where necessary and defects if any should be rectified.

vi) All nuts, bolts, check nuts and cotter pins of the lifting devices should be checked

periodically.



vii) All components should be greased and lubricated. Recommended and approved oils

and grease only should be used.

viii) Roller assembly should be adjusted by the eccentricity arrangement to ensure all

rollers rest uniformly on the track plates particularly in the closed position of the gate.

ix) All welds shall be checked for cracks/ damages. Any weld that might have become

defective should be chipped out and redone following the relevant codal provisions. Damaged

nuts, bolts, rivets, screws etc. should be replaced without delay.

x) The guide-assemblies, wheel-assemblies and sealing-assemblies shall be cleared off grit,

sand or any other foreign material.

xi) The wheel pin shall be coated with corrosion resistant compound.

xii) All nuts and bolts shall be tightened.

The aspects to be inspected and maintained periodically for ensuring proper operation of these

gates are as under:

a) Rubber Seals:

i) Seals shall be inspected for leakages. Locations of excessive leakages shall be recorded

for taking remedial measures. Weeping or slight flow in localized area will not require imme-

diate remedial measures. However, measures like tightening of bolts are carried out.Further

adjustment is carried out during annual maintenance.

ii) If leakage is excessive & immediate repair is considered necessary, the damaged seals

repaired or replaced as the case may be.

b) Trunnion block assembly and anchorages:

(i) All the nuts and bolts of Trunnion block assembly and its anchorages shall be checked

for tightness.

(ii) Check all the welds for soundness and rectify defects.

(iii) Cover the trunnion pin with anti- corrosive jelly.

(iv) Remove all dirt, grit etc. from trunnion assembly and lubricate trunnion bearings of

the gate with suitable water resisting grease as recommended by bearing manufacturers.



c) Gate structures:

i) Check all the welds for soundness and rectify defects.

ii) Check welds between arms and horizontal girders as well as between latching bracket

and skin plate with the help of magnifying glass for cracks/defects and rectify the defects.

iii) Clean all drain holes including those in end arms and horizontal girders.

iv) Check all the nuts and bolts and tighten them. Replace damaged ones.

v) Check upstream face of skin plate for pitting, scaling and corrosion. Scaling may be

filled with weld and grinded. Corroded surface shall be cleaned and painted.

d) Embedded Parts:

i) All the sill beams and wall plates shall be inspected for crack, pitting etc. and defects

shall be rectified.

e) General Maintenance:

i) Defective welding should be chipped out and it should be re-welded duly following

the relevant codal provision (IS: 10096, Part-3).

ii) Damaged nuts, bolts, rivets, screws etc. should be replaced.

iii) Any pitting should be filled up by welding and finished by grinding if necessary.

iv) The gate leaf, exposed embedded metal parts etc., should be thoroughly cleaned and

repainted when required keeping in view the original painting system adopted and as per the

guidelines contained in IS: 14177.

v) Trunnion bearing should be greased as and when required. Keeping trunnion bearings

in perfect working condition is very important. All other bolted connections should also be

checked up for proper tightness.

vi) Bolts and trunnion bearing housing should be tightened wherever required.

vii) The seals of the gate should be checked for wear and tear and deterioration. These

should be adjusted/replaced as and when necessary.

viii) The wall plates, sill beams shall be checked and repaired if necessary.

ix) Wire ropes should be properly lubricated.



x) Oil level in the worm reduction unit should be maintained by suitable replenishment.

Oil seals should also be replaced if required. Lubrication of other parts of hoists such as chains,

position indicators and limit switches should also be done.

xi) The stroke of the brake should be reset to compensate for lining wear. Worn out brake

linings should be replaced in time.

xii) Flexible couplings should be adjusted if required.

xiii) Repairs and replacements of all electrical relays and controls should be attended to.

xiv) Maintenance of alternative sources of Power such as Diesel Generating sets and alter-

native drives wherever provided should be carried out.

xv) The list of essential spare parts to be kept available should be reviewed and updated

periodically. The condition of spares should be checked periodically and protective coating

given for use.

4.2.5 Electrically operated fixed hoists

1. General Instructions:

a) Operation of fixed hoist without lifting the gate is not possible and need not therefore

be attempted. It will be possible to operate the unit and observe operation of load

carrying hoist component when gate is being lifted or lowered.

b) Never open any bolt or nut on motor, gear boxes, rope drums and other load carrying

hoist components when the gate is in raised position. The gate should be fully closed

or rested on the gate latches before carrying out any work on hoist components in-

cluding motor brake and other electrical equipment.

c) The aspects to be inspected and maintained periodically for ensuring proper operation

of Rope drum hoists are as under;

i. Entrance to all hoist platforms shall be kept locked. All keys shall remain with

the shift supervisor.

ii. A cursory daily inspection shall be made of hoist and gate to ensure that there

is no unusual happening.

iii. Clean all hoisting equipment and hoist platform.



iv. Check oil level in gearboxes and replenish as and when required with oil of

proper grade.

v. Apply grease of suitable grade by grease gun.

vi. Lubricate all bearings, bushings, pins, linkages etc.

vii. Check all the fuses on the power lines.

viii. All bolts and nuts on gear boxes, hoist drum and shaft couplings should be

checked for tightness.

ix. Check the supply voltage.

x. Drain sample gear oil from each of the gear boxes. If excessive foreign particles

or sludge is found, the gear box shall be drained, flushed and filled with new oil.

xi. All the geared couplings shall be greased.

xii. Raise and lower the gate by hoist motor and check for smooth, and trouble-

free operation of gate without excessive vibration.

xiii. Observe current drawn by motor at the time of lifting and check if it is more

than normal. If so, stop the hoist and investigate the cause and rectify.

xiv. Check the condition of painting of various components and remove rust wher-

ever noticed and repaint the portion after proper cleaning as per painting schedule.

xv. All trash, sediments and any other foreign material shall be cleared off the lift-

ing rope and lifting attachment.

xvi. All ropes shall be checked for wear and tear and if broken wires are noticed,

the rope shall be replaced.

xvii. All the wire ropes shall be checked and all visible oxidation shall be removed.

xviii. All wire ropes shall be greased with cardium compound.

xix. Check the overload relays for proper functioning.

xx. Check all the nuts, bolts, rivets, welds and structural components for hoisting

platform and its supporting structure for wear, tear and damage. All damages shall be



rectified. All bolts shall be tightened. The portion with damaged painting shall be

touched up.

xxi. Check the pulleys, sheaves and turn-buckles.

xxii. Raise and lower the gate for its full lift several time (at least three to four) and

observe the following:

a) Check the limit switches and adjust for design limits.

b) The effectiveness and slip of the breaks shall be checked by stopping the gate in raising and

lowering operations. The brakes shall be adjusted if needed.

c) When the gate is operated, there should not be any noise or chatter in the gears.

xxiv. Adjust the rope tension of wires if unequal.

xxv. Check for all gears and pinions for uneven wear and adjust for proper contact.

Grease the gears.

xxvi. Repaint the hoist components, hoisting platform and its supporting structures as

per requirement.

xxvii. The periodic maintenance of commercial equipment like motors, brakes, thrusts etc.

shall be carried out as per manufacturers operation and maintenance manual.

4.3. Maintenance of Electrical components of Fixed Rope Drum Hoists:

a). The electrical components to be inspected and maintained periodically are as under;

i)Starters should be cleaned free of moisture and dust.

ii) Each individual contactor should be tried by hand to make sure that it operates freely.

iii)All wearing parts should be examined in order to take note of any wear which may have

occurred during operation.

iv) If the contactor hums, the contact faces should be cleaned.

(v) Examine all connections to see that no wires are broken and no connections are loose.

vi) Clean the surface of the moving armature and magnet core which comes together when

the contactor closes, free of dust or grease of any kind.



vii) Examine the mechanical interlocks between the reversing contactor and see when the

contact tips of one of the contactor units are touching, it is impossible to get the contact

tips of the other unit to touch.

viii) The contact tips should be kept free from burns or pits by smoothening with fine sand

paper or emery paper.

ix) Replace the contact tips which have worn away half-way.

x) Do not lubricate the contacts.

xi) Blow out windings thoroughly by clean and dry air to clear air passage in the stator and

the rotor of any accumulated dirt. The air pressure shall not be too high to damage the

insulation.

xii) Examine earth connections and motor leads.

xiii) Examine motor windings for overheating

xiv) Examine control equipment’s

xv) Examine starting equipment for burnt contacts

xvi) Check and tighten all nuts and bolts

xvii) Clean and tighten all terminals and screw connections all contact surfaces shall be

made clean and smooth.

xviii) Lubricate the bearings

xix) Overhaul the controllers

xx) Inspect and clean circuit breakers.

xxi) Wipe brush holders and check bedding of brushes.

xxii) Blow out windings thoroughly by clean and dry air. The pressure shall not be so

high that insulation may get damaged.

xxiii) Check the insulation resistance of the motor between any terminal and the frame.

If the measured resistance is less than the prescribed value, then steps shall be taken to

dry- out the motors either by passing a low voltage current through the windings or by

placing the stator and rotor only in a warm dry place for a day or so.

WARNING: The complete motor shall never be put in an oven

for drying as that may melt the grease out of bearings.



xxiv) Coat the windings with an approved high temperature resisting insulation enamel

or varnish.

xxv) Over haul the motor, if required.

xxvi) Check the switch fuse units and renew, if required.

xxvii) Check resistance or earth connections.

xxviii) Check air gap.

b) Solenoid Operated Brakes

i) All fixing bolts shall be checked and tightened at least once in three months.

ii) The magnet stroke should be reset to compensate for wear.

iii) Re-adjust the brake when the magnet stroke reaches the value given on the instruc-

tion plate.

iv) Brake lining should be checked and replaced when required.

v) Examine all electrical leads and connections.

vi) Rubber bushes or couplings should be checked and replaced if defective.

vii) The pins should be tightened.

viii) Brake drum shall be cleaned to remove any dust or grease,

lifting beam & gantry crane

4.4 Surface Preparation and Painting of HM Works

i) Protection of painted surfaces is considered essential for protection & enhancement of service

life. Gates, their embedded parts, gate leaf, hoists and its supporting structures need to be

protected against corrosion due to climatic condition, weathering, biochemical reaction and

abrasion etc. This equipment is likely to deteriorate or get damaged to any extent that the

replacement of parts may become necessary and such replacement may become difficult and

costly.

ii) Surface preparation & Painting requirements:

Painting for hydro-mechanical works is to be carried out as prescribed in IS 14177 for both newly

manufactured as well as old & used gates, hoists and associated works after proper surface

preparation. The preparation includes thorough cleaning, smoothing irregular surfaces, rusted



surfaces, weld spatters, oil, grease, dirt, earlier applied damaged layers of primers/ paint by use

of mechanical tools, by use of solvents, wire brush etc. The sand / grit blasting process is used

for surface preparation to a level of Sa 2½ of the Swedish standard.

iii) Surfaces not requiring painting & their protection during surface preparation, painting

& transportation process:

a) The following surfaces are not to be painted unless or otherwise specified:

• Machine finished or similar surface

• Surfaces which will be in contact with concrete

• Stainless steel overlay surfaces.

• Surfaces in sliding or rolling contact

• Galvanized surfaces, brass and bronze surfaces.

• Aluminum alloy surfaces

b) The Surfaces of stainless steel, nickel, bronze and machined surface adjacent to metal work

being cleaned or painted shall be protected by using sticky protective tape or by other

suitable means over the surfaces not to be painted.

c) All embedded parts which come in contact with concrete shall be cleaned as detailed above

and given two coats of cement latex to prevent rusting during the shipment while awaiting

installation.

iv) Application of primer &finish coats on embedded parts and gates:

a) EMBEDDED PARTS:

• The prescribed primer shall be applied as soon as the surface preparation is complete

and prior to the development of surface rusting and within the specified time pre-

scribed by Indian Standards or the Paint Manufacturer. In case there is lapse of con-

siderable time beyond the prescribed time limit, the surfaces shall be again cleaned

prior to priming.

• Two coats of zinc rich primer with epoxy resin shall be applied to all embedded parts

surfaces which are not in contact with concrete and shall remain exposed to atmos-

phere or submerged in water to obtain a dry film thickness of 75 microns.



• This shall be followed by three coats at an interval of 24hours of coal-tar blend epoxy

resin so as to get a dry film thickness of 80 microns in each coat. Total dry film thick-

ness of paint shall not be less than 300 microns.

b) GATES:

Primer Coat:

• Over the prepared surface one coat of inorganic zinc silicate primer giving a dry film

thickness of 70 ± 5 microns should be applied. Alternatively, two coats of zinc rich

primer, which should contain not less than 85% zinc on dry film should be applied to

give a total dry film thickness of 75 ± 5 microns.

Finished paint:

• Two coats of solvent less coal tar epoxy paints. These shall be applied at an interval of

about 24 hours. Each coat shall give a dry film thickness of 150±5 microns. The total

dry film thickness of all the coats including primer coating shall not be less than 350

microns.

v) Hoist and supporting structure:

a) Structural components:

Primer coats of zinc phosphate primer shall be applied to give a dry film thickness of 40±5 mi-

crons.

Final Coats: One coat of alkalized based micaceous iron oxide paint to give a dry film thickness of

65 ± 5 microns followed by two coats of synthetic enamel paint confirming to IS 2932 – 1974

to give a dry film thickness of 25 ± 5 microns per coat. The interval between each coat shall

be 24hours. The total dry thickness of all coats of paint including the primer coat shall not be

less than 175 microns.

b) Machinery: Except machined surfaces all surfaces of machinery including gearing, housing,

shafting, bearing pedestals etc., shall be given:

Primer coats: One coat of zinc phosphate primer paint to give minimum film thickness of 50

microns. Motors and other bought out items shall be painted if necessary.

Finished coats: The finished paint shall consists of three coats of aluminum paint confirming

to IS2339 – 1963 or synthetic enamel paint confirming to IS 2932 – 1977to give a dry film



thickness of 25±5 microns per coat to obtain a total minimum dry film thickness of 125 mi-

crons.

c) Machined surfaces:

All machined surfaces of ferrous metal including screw threads which will be exposed during

shipment or installation shall be cleaned by suitable solvent and given a heavy uniform coating

of gasoline soluble removable rust preventive compound or equivalent. Machined surfaces

shall be protected with the adhesive tapes or other suitable means during the cleaning and

painting operation of other components.

vi) Application of paint:

Mix the contents thoroughly as directed by paint manufacturer before and during use.

Painting at shop can be done by any of the three methods namely Brush / roller, Conventional

spray, Airless spray etc.

The paint can be made to suit the adopted method. But once the gate and equipment is in erected

position the general method adopted is only brush / roller. In case of spray lot of precautions are

to be taken.

For More details: Refer IS: 14177 Part (II) – 1971.

Appendix A – Brushing of paint

Appendix B – Spraying of paint

Appendix C – Spray painting defects: Causes and remedies.

Removal of old paint / rust and carrying out fresh painting:

The carrying out of fresh painting is to be considered under the following conditions:

• The rusting is noticed all over the surface or

• Rusting is severe or

• Cracking and blistering has damaged the primer coat exposing the metal and is noticed all

over the surface or

• The paint film has eroded badly, the scrap of entire paint film to the base metal andcarry

out fresh painting.



Note: In case of maintenance and renovation: Refer IS 14177 (Part II) – 1971 for checking

and repainting.

vii) Removal of old paint for repainting:

Caution should be exercised while removing the old paint. The surfaces shall be de-rusted and

descaled by either mechanically by one or more of the methods, namely:

a) Wire brushing, Scraping, and chipping. Sand papering or cleaning with steel wool or abra-

sive paper

b) Power tool cleaning

c) Flame cleaning

d) Sand blasting or shot blasting and

e) Chemical rust removal.

Note: The method of application shall be decided based on conditions existing. After cleaning

painting is to be carried out as originally proposed.

Some are painted without removal of old paint and rusting this will amounts to no painting

and deteriorate faster than the original one.

viii) Inspection and testing of painting of H. M works:

a) The following steps are involved in inspection of painting:

• General inspection before and during painting

• Viscosity test of paints

• Paint thickness test – using Elco-meter.

• Inspection of general appearance of finished work.

b) General:

The aim of inspection and testing is to ascertain whether the recommended practice is being

employed correctly during every stage of application and whether the final results fulfill the object

of painting. Any test carried out should be of non – destructive nature or, if it is of destructive

nature, it should be either restricted to areas which can be restored without marring the general

appearances or be such that it is possible to restore easily without necessitating a complete repe-

tition of the work.



c) Inspection of surfaces prior to painting:

Inspection methods will depend on whether it is to be painted for the first time or is to be re-

painted.

d)New Works (Not previously painted): The following shall be decided by inspection:

• The method of pre cleaning feasible or recommended;

• The intermediate protective treatments to be applied, if found necessary;

• The final painting schedule and the specifications for the paint for ensuring the particular

performance;

• The method of application, whether by brush, roller or spray.

e) Old Work (Which requires repainting):

The following shall be decided by inspection:

• Whether the entire existing paint requires removal; and/or

• Whether repainting without paint removal would be adequate.

4.5 Electrical System

Electricity is typically used at a dam for lighting and to operate the gates, hoists, recording equip-

ment, and other miscellaneous equipment. It is important that the Electrical system be well main-

tained, including a thorough check of fuses and a test of the system to ensure that all parts are

properly functioning. The system should be free from moisture and dirt, and wiring should be

checked for corrosion and mineral deposits.

All necessary repairs should be carried out immediately and records of the works kept. Maintain

generators used for auxiliary emergency power -- change the oil, check the batteries and antifreeze

and make sure fuel is readily available.

Monitoring devices usually do not need routine maintenance. Open areas are particularly suscep-

tible to vandalism. As such all electrical fittings like bulbs, lights, loose wires etc. in open areas

should be checked routinely and replaced / repaired where needed. The recommendations of the

manufacturer should also be referred to.

4.6 Maintenance of Metal Gate Components

All exposed, bare ferrous metal of an outlet installation, whether submerged or exposed to air, will

tend to rust. To prevent corrosion, exposed ferrous metals must be either appropriately painted



(following the paint manufacturer’s directions) or heavily greased in respect of moving parts & on

surfaces like guides & track seats on which there is movement of gates. When areas are repainted,

it should be ensured that paint is not applied to gate seats, wedges, or stems (where they pass

through the stem guides), or on other friction surfaces where paint could cause binding. Heavy

grease should be applied on friction surfaces to avoid binding. As rust is especially damaging to

contact surfaces, existing rust is to be removed before periodic application of gr-ease.

4.7 Access Roads

For a dam to be operated and maintained, there must be a safe means of access to it at all times.

Access road surfaces must be maintained to allow safe passage of automobiles and any required

equipment for servicing the dam in any weather conditions. Routine observations of any cut and

fill slopes along the sides of the road should be made. If unstable conditions develop assistance of

experienced Engineers/Expert Panels should be obtained and remedial measures initiated.

Drains are required to be provided and maintained along roads to remove surface and subsurface

drainage. This will prolong the life of the road and help reduce deterioration from rutting. Road

surfacing should be repaired or replaced as necessary to maintain the required traffic loadings. In

most cases, specialized contractors will be required to perform this maintenance.

4.8 General Cleaning

As already suggested, for proper operation of spillways, sluiceways, approach channels, inlet and

outlet structures, stilling basin / energy dissipation arrangements, discharge conduit, dam slopes,

trash racks, debris control devices etc., regular and thorough cleaning and removal of debris is

necessary. Cleaning is especially important after large floods, which tend to send more debris into

the reservoir.

4.9 Materials and Establishment Requirements during Monsoon Period

Materials required during monsoon period for both immediate maintenance and preventive

maintenance must be stocked in adequate quantities for emergency situations that may arise.

Needful instructions in this regard is enclosed in the O&M Manual. At Hemavathy Dam, a 24/7-

hour patrol schedule is carried out during monsoon period. At the same time the additional man-

agement requirements during monsoon period are enhanced.



4.10 General List of Maintenance Records

Maintenance records are of utmost importance. Records are kept of all maintenance activities,

both immediate and preventive maintenance works. Essential information to be recorded include

the following:

• Date and time of maintenance,

• Weather conditions,

• Type of maintenance,

• Name of person, title and / or contractor performing maintenance,

• Description of work performed,

• Length of time it took to complete the work with dates,

• Equipment and materials used, and

• Before and after dated photographs.

The data is recorded by the person responsible for maintenance.

4.11 Preparation of O&M budget

The O&M budget for Hemavathy dam includes the following items:

i) Establishment Cost of Regular Staff - Salaries and allowances, Bonus, Medical Re-

imbursement, LTC, Leave Encashment, pension benefits, etc. (as applicable).

ii) Establishment Cost of Work charged Staff - Salaries and allowances, Bonus, Med-

ical Reimbursement, LTC, Leave Encashment, Pension benefits, TA and DA , etc. (as

applicable).

iii) Establishment Cost of Daily wage Staff - Salaries and allowances, TA and DA etc.

(as applicable).

iv) Office Expenses – Rent for office, Telephone/Mobile/any other Telecommunica-

tion bills, Electricity bills, water bills, Office stationery, Day to day office requirements.

v) Motor Vehicles - Running and Maintenance cost of inspection vehicles, Cost of hiring

of vehicles as required

vi) Maintenance of Colony - Maintenance of staff quarters, colony roads, Electricity,

Sanitary and Water supply systems etc.

vii) T&P - T&P requirements for offices, colony, works etc. as applicable.

viii) Works -Painting, oiling, greasing, overhauling of HM equipment’s, Repair/replace-

ment of gates seals & wire ropes, POL for pumps & generator sets, Electricity charges

and maintenance of Electric systems of dam site, specific requirements for all Civil,



H.M & Electrical maintenance works, vegetation removal and mowing of turfing on

earth dams, maintenance/cleaning of drains in dam, maintenance of lift/elevators in

dam (as applicable), maintenance of access roads & basic facilities, provision for flood

contingency works during monsoon, unforeseen events/items (about 10% of the cost

of works) etc.

Table 19 -O&M BUDGET COSTS (ANNUAL)

SL.

NO. BUDGET ITEM

PREVIOUS

YEAR COST

(Rs)(2018-19

0

CURRENT

YEAR

BUDGET

(YR 2019-20)

(Rs)

REMARKS

A.ESTABLISHMENT

1

SALARY OF REGULAR

STAFF INCLUDING ALL

OTHER BENEFITS

13557820 14235711

2 TRAVEL EXPENSES 206444 206444

3 OFFICE EXPENSES 5000000 5000000

4 MOTOR VEHICLE EX-

PENSES 700000 700000

5

MAINTENANCE OF OF-

FICE & COLONY COM-

PLEX

6600000 6600000

SUB-TOTAL - A 26064264 26742155

B. WORKS

1 CIVIL

1.1 CONCRETE / MASONRY

DAM 1000000 1000000

1.2 EARTHEN DAM 4500000 4500000



1.3 INTAKE / OUTLETS IN

EARTHEN DAMS 500000 500000

1.4 SLUICES IN CONCRETE /

MASONRY DAMS 500000 500000

1.5

APPROACH / INSPECTION

ROADS WITHIN DAM

AREA

1000000 1000000

2 HYDRO-MECHANICAL

2.1 SPILLWAY GATES &

HOISTS - 2600000

2.2 SPILLWAY STOP-LOG &

GANTRY CRANE 4000000 -

2.3

OUTLETSIN EARTHEN

DAMS - SERVICE / EMER-

GENCY GATES & HOISTS

2500000 15000000

2.4

SLUICES IN CONCRETE /

MASONRY DAMS – SER-

VICE / EMERGENCY

GATES & HOISTS

3500000 17500000

3 ELECTRICAL

3.1

ELECTRICAL FITTINGS,

MOTORS, CONTROLS FOR

ALL GATE HOISTS

700000 700000

3.2 POWER SUPPLY LINES 500000 500000

3.3

ELECTRICAL FITTINGS ON

DAM TOP, DAM GALLER-

IES, ETC.

1000000 1000000

3.4 STANDBY POWER / DIE-

SEL GENERATOR 600000 600000

3.4 REMOTE CONTROL/CCTV - -



4 INSTRUMENTATION

5 MISCELLANEOUS WORKS 200000 200000

6

SALARY OF WORK-

CHARGED STAFF IN-

CLUDINGALL BENEFITS

- -

7

MATERIALSTO BE

STORED BEFORE MON-

SOON

200000 200000

SUB-TOTAL - B 20700000 45800000

8 CONTINGENCY (10%) ON

SUB-TOTAL OF A & B 4676426.4 7254215.5

9 TOOLS & PLANTS 25000 25000

SUB-TOTAL- C 25000 25000

10 TOTAL ANNUAL COST 51465690.4 79821370.5

4.13 Maintenance Records

Maintenance records are of utmost importance. A record shall be kept for all maintenance

activities, both immediate and preventive maintenance works. Information that must be recorded

includes, but not limited to, the following:

• date and time of maintenance,

• weather conditions,

• the type of maintenance,

• name of person or contractor performing maintenance,

• description of work performed,

• the length of time it took to complete the work with dates,

• equipment and materials used, and

• before and after photographs.

The data should be recorded by the person responsible for maintenance.



CHAPTER 5 - INSTRUMENTATION AND MONITORING

5.1 Dam Instrumentation:

5.1.1General Information

This section identifies the location and chainages of each of the 4 structural components of the

dam:

Table 20- Location and Extents of Structural Members

5.1.2 Instruments Embedded in the Hemavathy Earthen Dam

The seepage measuring piezometer instruments have been embedded in the Earthen Dam section.

Table 21 -Embedded Instruments

Sl.

Type of

Instruments

Embedded

No. of Instruments embedded in Frequency of moni-

toring

At chainage 2058mtr

1 Pressure Pi-

ezometers

13 Nos. of Vertical pressure pie-

zometers

Daily

5.1.3 Additional instruments planned to install under DRIP.

Table 22 - Additional Instruments.

SI No Details of Instruments unit

1 Automatic Weather Station 1

2 Plumb line (Normal & Inverted) Automatic only 1

From Chainage To Chainage

Earthen Embankment 150.00 1630.00

Non-Overflow Section (left of

overflow section) 1630.00 1783.00

Over-flow Section 1783.00 1880.00

Non-Overflow Section (right of

overflow section) 1880.00 1995.00



SI No Details of Instruments unit

3 Thermometers 1

4 Tilt meters 1

5 Uplift gauges 10

6 Data centre at dam site logger etc 1

7 Total station 1

8 Gate Sensor 8

9 Sirens 1

5.1.4 Seismological Observations

A seismological observatory has been established at Hemavathy Dam & the data is being recorded

at KSNDMC (Karnataka State Natural Disaster Monitoring Centre Cell) office in Bangalore.

The earthquake recording machine installed is "Protocorder RV- 320 B” type with seismometers

of type 5 - 7000Model.The observations from earthquakes are being observed and noted by the

Quality Control Authorities.

Detailed description on instrumentation in dams is available in “Guidelines for instrumentation in dams (CWC, 2018).” The document can be found under the link: https://damsafety.in/ecm-in-cludes/PDFs/Guidelines_for_Instrumentation_of_Large_Dams.pdf. However, an overview of the same is given below.

5.1.5 Parameters being permanently Monitored

Observations of the following parameters need to be continued but not limited to;

• Water levels in the reservoir.

• Hydro-meteorological observations.

• Seepage observations using V-notches/ weirs etc.

• Displacements in the dam by means of survey observations using prism/paper targets fixed at structures, tilt meters or repaired plumb lines, etc.

• Uplift pressures at dam base using stand pipes in Gravity dams.

In case some of the instruments are not in working condition, following are some of the steps to be done;



i) In case connecting cables of the non-working instruments are accessible, the manufac-turer of the said instruments should be approached for checking and rectification of the installations to make instruments work.

ii) In case the embedded non-working instruments cannot be repaired, the same are to be abandoned.

5.1.6 Frequency of Monitoring

As a rule of thumb, simple visual observations should be made during each visit to the dam and not less than monthly. Immediate readings should be taken following a storm

or earthquake. Suggested frequency of measurements is given in the following table. These are generally as per the Guidelines on Instrumentation for dams (CWC).

Table 23- Frequency of Readings for Hemavathy Dam.

No. INSTRUMENT MINIMUM FREQUENCY

OF READING

1 Piezometers (Manual Readout unit) Daily

2 Uplift Pressure gauge Monthly

3 V Notch Daily

Additional Instruments

4 Automatic Weather Station Daily

5 Plumb line ( Normal & Inverted) Automatic only

Monthly

6 Thermometers Daily

7 Tilt meters Monthly

8 Uplift gauges Monthly

9 Data centre at dam site logger etc Daily

10 Total station Monthly

11 Gate Sensor Daily

12 Sirens -



CHAPTER 6 - PREVIOUS REHABILITATION EFFORTS

Before DRIP, maintenance activities were limited to routine greasing, oiling, and painting to elec-

tro-mechanical devices; routine repair of electrical systems; gallery drainage; routine mowing, veg-

etation removal, repair of eroded section, etc. Apart from these routine maintenance activities, no

major rehabilitation was carried before the involvement of DRIP. Under DRIP, major Rehabilita-

tion Works have been carried out at a total cost of about INR 8.64 Crores. The rehabilitation

works under DRIP include:

Costs (INR)

Name of Work

Original

Contract

Amount

(in Millions)

Supplementary

Contract

Amount

(in Millions)

Revised

Agreement

amount (in

Millions)

1. Reconstruction of upstream Re-

vetment of Hemavathy Dam.

2. Providing pointing to the stone

cladding below the Parapet wall

on upstream surface and Treat-

ment of the masonry Portion on

the upstream surface of the

Hemavathy Dam.

3. Extension of River Training/ Pro-

tection walls to the left and right

flanks of Hemavathy river on the

down stream of Hemavathy Dam.

4. Rehabilitation of Damaged sur-

face of spillway and Flip bucket

portion of Hemavathy Dam.

5. Providing shortcreting to up-

stream surface

of spill way piers of Hemavathy

Dam.

86.49 21.5 107.99



CHAPTER 7 - UPDATING THE MANUAL

As features of the dam and appurtenant structures change occasionally, the O&M Manual must

be edited and portions rewritten to reflect these changes. This important task is often ignored.

Updating information in the O&M Manual should be done whenever major changes like construc-

tion of an additional spillway, construction of dam on the upstream etc. take place. Aspects to be

considered when updating include:

• Increase/decrease in the frequency of an inspection or the maintenance routine based on

additional data/ experience acquired.

• Changes in the operation and/or maintenance procedures based on additional data/experi-

ence acquired.

• Alterations to the project data because of changes/modifications in the dam by way of addi-

tional spillway etc.

All up-dates/revisions of the O&M Manual need to be sent to all the locations/addresses to whom

the copies of the original O&M Manual had been sent earlier. It is recommended that O&M Man-

uals be reviewed/ updated after every 10 years by the respective Dam Owners.



APPENDIX I – BASIC DRAWINGS OF HEMAVATHY DAM



Longitudinal section of the Hemavathy dam





Cross section of the Earthen dam











APPENDIX II― KEY ELEMENTS OF THE EAP



A 2.1 HEMAVATHY DAM – WATCH CONDITION NOTIFICATION FLOWCHART

RESOURCE AVAILABLE

HEAVY EQUIPMENT SERVICE Name : S Narayan Reddy Title : Class 1 Contractor Mob : 9448142276 Off : Email: Name : K C Shyamanna Title : Class 1 Contractor Mob : 9900717383 Off : Email: Name : G M Dhananjay Title : Class 1 Contractor Mob : 9448742983 Off : Email:

Chief Engineer, Hemavathy Reservoir Pro-ject, Gorur Name : C Manjappa (I/C) Title : Chief Engineer Mob : 9448088467 Off : 08172-225437 Email : [email protected] Name : Prasad Title : Deputy Chief Engineer Mob : 8548049456 Off : 08172-225437 Email : [email protected]

Superintending Engineer Hemavathy Dam Name : C Manjappa Title : Superintending Engineer Mob : 9448088467 Off : 08172-225423 Email : [email protected]

Assistant Executive Engineer (Dam Site) Name : Sreenatha S V Title : Assistant Executive Engineer Mob : 9448871009 Off : 08172-225427 Email : [email protected]

Executive Engineer Of Hemavathy Dam(Dam Safety Engineer) Name : Gangadhar (I/C) Title : Executive Engineer Mob : 9448427354 Off : 08172-225425 Name : Puttaswamy (I/C) Title : Assistant Engineer ( PA to AE) Mob : 9448734343 Off : 08172-256749 Email : [email protected]

Assistant Engineer (Dam Site) Name : Venkataravanappa C M Title : Assistant Engineer Mob : 9845905745 Off : 08172-225427 Name : Srinivasa Title : Work Inspector Mob : 8496845335 Name : Swamy Title : Gate operator Mob : 9663654976

OBSERVER OF EVENT

Deputy Commissioner Hassan District Name : Priyanka Mary Francis Title : Deputy Commisioner Mob : 9483963333 Off : 08172-267345 Off2 : 08172-265418 Email : [email protected] Name :Vyshali M L Title : Additional Deputy Commisioner Mob : Off : 08172-268402 Email : [email protected]

Superintendent of police Hassan District Name : Dr Chetan Singh Rathor Title : Superintendent of Police Mob : 9480804701 Off : 08172-268410 Email : [email protected]

Deputy Commissioner Mandya District Name : P C Jaffer Title : Deputy Commisioner Mob : Off : 08232-224600 Email : [email protected] Name : Title : Additional Deputy Commisioner Mob : Off : 08232-224023 Email : [email protected]

Superintendent of police Mandya District Name : Shiva Prakash Devaraju Title : Superintendent of Police Mob : Off : 08232-224500 Email : [email protected]

Tahsildar KrishnarajaPete Taluk , Manyda Disrtrict Name : Rathana Title : Tahsildar Mob : 9449816007 Off : 08230-262227 Email : [email protected]

Tahsildar Hassan Taluk , Hassan Disrtrict Name : Shivashankarappa Title : Tahsildar Mob : 9448868443 Off : 08172-268395 Email : [email protected]

Tahsildar Channarayapatna Taluk , Hassan Disrtrict Name : Somasekar Title : Tahsildar Mob : 9448741918 Off : 08176-255219 Email : [email protected]

Tahsildar Holenarasipura Taluk , Has-san Disrtrict Name : Renukumar Title : Tahsildar Mob : 9448158273 Off : 08175-273261 Email : [email protected]

Tahsildar Arkalgud Taluk , Hassan Disrtrict Name : Prasanna Murthy Title : Tahsildar Mob : 8904766989 Off : 08175-220246 Email : [email protected]

Chief Engineer Irrigation South Mysore ( Downstream) Name : Shankare Gowda Title : Chief Engineer Mob : 9632393263 Off1 : 0821-2443900 Off2 : 0821-2443603

SAND & GRAVEL SUP-PLY Name : K A Indresh Title : Class 1 Contractor Mob : 9448413800 Off : Email: Name : M Shivashankara Title : Class 1 Contractor Mob : 9448171189 Off : Email: Name : S R Gopal Title : Class 1 Contractor Mob : 9448503691 Off : Email:

SUPPLY OF READY MIX CONCRETE Name : K Venkataraanareddy Title : Class 1 Contractor Mob : 9448350350 Off : Email: Name : K M Paramesh Title : Class 1 Contractor Mob : 9448120087 Off : Email: Name : Shivaram Title : Class 1 Contractor Mob : 9448271033 Off : Email:

mailto:[email protected]





HEMAVATHY DAM – FAILURE CONDITION NOTIFICATION FLOWCHART

Dam Site Office Name : Sreenatha S V Title : Assistant Executive Engineer Mob : 9448871009 Off : 08172-225427 Name : Venkataravanappa C M Title : Assistant Engineer Mob : 9845905745 Off : 08172-225427

OBSERVER OF EVENT

Chief Engineer, Hemavathy Reservoir Project, Gorur Name : C Manjappa (I/C) Title : Chief Engineer Mob : 9448088467 Off : 08172-225437 Email : [email protected] Name : Prasad Title : Deputy Chief Engineer Mob : 8548049456 Off : 08172-225437 Email : [email protected]

Superintending Engineer Hemavathy Dam Name : C ManjappaTitle : Superintend-ing EngineerMob : 9448088467Off : 08172-225423Email : [email protected]

Executive Engineer Of Hemavathy Dam(Dam Safety Engineer) Name : Gangadhar (I/C) Title : Executive Engineer Mob : 9448427354 Off : 08172-225425 Name : Puttaswamy Title : Assistant Engineer ( PA to AE) Mob : 9448734343 Off : 08172-256749 Email : [email protected]

Deputy Commissioner Hassan District Name : Priyanka Mary Francis Title : Deputy Commisioner Mob : Off : 08172-267345 Off2 : 08172-265418 Email : [email protected] Name :Vyshali M L Title : Additional Deputy Commisioner Mob : Off : 08172-268402 Email : [email protected]

Deputy Commissioner Mandya District Name : P C Jaffer Title : Deputy Commisioner Mob : Off : 08232-224600 Email : [email protected] Name : Title : Additional Deputy Commisioner Mob : Off : 08232-224023 Email : [email protected]

Superintendent of police Hassan District Name : Dr Chetan Singh Rathor Title : Superintendent of Police Mob : Off : 08172-268410 Email : [email protected]

Superintendent of police Mandya District Name : Shiva Prakash Devaraju Title : Superintendent of Police Mob : Off : 08232-224500 Email : [email protected]

Office of Karnataka Water Resources Department Name : Prabhakarahemmige Title : Chief Engineer Mob : 9902815938 Off : 080-22871174 Email : [email protected]

Managing Director Cauveri Neeravari Nigama Niyamitha Bengaluru Name : H L Prasanna Title : Chief Engineer Mob : 9483510818 Off : 080-22354900 Email : [email protected]

CWC Divisional Office Name : Title : Mob : Off : Email :

CWC Regional Headquartes Name : Title : Mob : Off : Email :

Chief Engineer Irrigation South Mysore ( Downstream) Name : Shankare Gowda Title : Chief Engineer Mob : 9632393263 Off1:0821-2443900 Off2 : 0821-2443603

RESOURCE AVAILABLE

HEAVY EQUIPMENT SERVICE Name : S Narayan Reddy Title : Class 1 Contractor Mob : 9448142276 Off : Email: Name : K C Shyamanna Title : Class 1 Contractor Mob : 9900717383 Off : Email: Name : G M Dhananjay Title : Class 1 Contractor Mob : 9448742983 Off : Email:

SAND & GRAVEL SUPPLY Name : K A Indresh Title : Class 1 Contractor Mob : 9448413800 Off : Email: Name : M Shivashankara Title : Class 1 Contractor Mob : 9448171189 Off : Email: Name : S R Gopal Title : Class 1 Contractor Mob : 9448503691 Off : Email:

SUPPLY OF READY MIX CONCRETE Name : K Venkataraa-nareddy Title : Class 1 Contractor Mob : 9448350350 Off : Email: Name : K M Paramesh Title : Class 1 Contractor Mob : 9448120087 Off : Email: Name : Shivaram Title : Class 1 Contractor Mob : 9448271033 Off : Email:






A 2.2 Evidence of Distress

General obser-vation

Specific

observation

Emergency condition

level

Emergency action Equip-ment,

material, and sup-

plies

Data to record

Bo

ils

Small boils, no in-crease of water flow, flowing clear water.

BLUE

Closely check all of down-stream toe, especially in the vicinity of boil for addi-tional boils, wet spots, sinkholes, or seepage. Closely monitor entire area for changes or flow rate in-creases.

None Site and loca-tion, ap-proxi-mate flow

Large or additional boils near previ-ously identified ones, without in-creasing flow rate, but carrying small amount of soil par-ticles.

BLUE

Initiate 24-hour surveil-lance. Monitor as de-scribed above. Construct sandbag ring dikes around boils, to cover them with water to retard the move-ment of soil particles. Filter cloth may be used to retard soil movement, but do not retard the flow of water.

Sand-bags, fil-ter cloth

Site and loca-tion, ap-proxi-mate flow

Large or additional boils near previ-ously identified ones, increasing flow rate, carrying soil particles.

ORANGE

Continue 24-hour surveil-lance. Continue monitor-ing and remedial action as described above. Initiate emergency lowering of the reservoir. Issue a warning to downstream residents.

Sand-bags, pump


Rapidly increasing size of boils and flow increasing and muddy water.

RED

Downstream evacuation. Employ all available equip-ment to attempt to con-struct a large ring dike around the boil area.

Dozer, shovels, source of earth fill


Seep

ag

e

Minor seepage of clear water at toe, on slope of em-bankment, or at the abutments.

BLUE

Closely check entire em-bankment for other seep-age areas. Use wooden stakes or flagging to delin-eate seepage area. Try to channel and measure flow. Look for upstream whirl-pools.

Wooden stakes, flagging

Site, lo-cation, approx-imate flow

Additional seepage areas observed flowing clear water

BLUE Initiate 24-hour surveil-lance. Monitor as de-scribed above. Construct

Dozer, Shovels

Site, lo-cation,




Specific

observation

Emergency condition

level


material, and sup-

plies

Data to record

and/or increasing flow rate.

measuring weir and chan-nel all seepage through weir. Attempt to determine source of seepage.

approx-imate flow

Seriously or rapidly increasing seep-age, under-seep-age, or drain flow. ORANGE

Continue 24-hour monitor-ing and remedial action as described above. Initiate emergency lowering of the reservoir. Construct a large ring dike around the seep-age area.

Dozer, shovels, source of fill mate-rial

Site lo-cation, approx-imate flow

Additional seepage areas with rapid in-crease in flow and muddy water.

RED

Downstream evacuation. Employ all available equip-ment to attempt to con-struct a large ring dike around the seepage area.


Site lo-cation, approx-imate flow

Sli

des

or

seve

re e

rosi

on

Skin slide or slough on slope of embankment. No further movement of slide and em-bankment crest not degraded.

BLUE

Examine rest of embank-ment for other slides. Place stakes in slide material and adjacent to it for determin-ing if further movement is taking place.

Stakes, tape measure

Dis-tance be-tween stakes

Slide or erosion in-volving large mass of material, crest of embankment is de-graded, no move-ment or very slow continuing move-ment.

BLUE

Initiate 24-hour surveil-lance. Mobilize all availa-ble resources and equip-ment for repair operations to increase freeboard and to protect the exposed em-bankment material. Start filling sandbags and stock-pile near slide area.

Dozer, shovels, sources of fill material, sand-bags


Slide or erosion in-volving large mass of material, crest of embankment is de-graded, progres-sively increasing in size.

ORANGE

Continue monitoring and remedial actions as de-scribed above. Place addi-tional material at the toe of the slope to stop the slide.

Dozer, shovels, source of fill mate-rial, pump


Slide or erosion in-volving large mass of material, crest of embankment is

RED

Downstream evacuation. Utilize all available equip-ment and personnel to sandbag the degraded

Dozer, shovels,

Dis-tance




Specific

observation

Emergency condition

level


material, and sup-

plies

Data to record

severely degraded, movement of slide is continuing and may reach pool level.

slide area to prevent it from overtopping.

sand-bags, pump

be-tween stakes

Sin

kh

ole

s

Sinkholes any-whereon the em-bankmentor within 150 metresdown-stream from the toe.

BLUE

Carefully walk the entire embankment and down-stream area looking for ad-ditional sinkholes, move-ment, or seepage.

Stakes, flagging

Size, lo-cation

Sinkholes with cor-responding seep-age anywhere on the embankment or downstream from the toe.

BLUE

Initiate 24-hour surveil-lance. Monitor as above. Construct sandbag dike around the seepage exit point to reduce the flow rate. Start filling sandbags and stockpile near sink-hole.

Dozer, shovels, pump

Size, lo-cation

Large sinkholes with correspond-ing seepage any-where on the em-bankment or downstreamfrom the toe.

ORANGE

Continue monitoring and remedial action as de-scribed above. Utilize sandbags to increase the freeboard on the dam if necessary.

Sand-bags, dozer, pump

Size, lo-cation

Sinkholes rapidly getting worse, seepage flowing muddy water and increasing flow.

RED

Downstream evacuation. Utilize all available equip-ment and personnel to at-tempt to construct a large ring dike around the area.

Dozer, shovels, pump

Size, lo-cation

Sett

lem

en

t

Obvious settle-ment of the crest of the embankment, especially adjacent to concrete struc-tures.

BLUE

Look for bulges on slope or changes in crest align-ment.

None Size, lo-cation

Settlement of crest of embankment that is progressing, especially adjacent to concrete struc-tures or if any

BLUE

Initiate 24-hour surveil-lance. Mobilize all availa-ble resources for repair op-erations to increase free-board. Fill and stockpile sandbags. Identify any

Sand-bags, dozer, shovels, source of

Size, lo-cation




Specific

observation

Emergency condition

level


material, and sup-

plies

Data to record

corresponding seepage is present.

boils near settlement points for flowing material and pursue action for boils.

fill mate-rial

Settlement of crest of embankment that is rapidly pro-gressing especially adjacent to con-crete structures or if any correspond-ing seepage is flowing muddy wa-ter or increasing flow.

ORANGE

Continue monitoring and remedial actions as de-scribed above. Use sand-bags to increase the free-board on the dam if neces-sary.

Sand-bags, shovels, dozer, source of fill mate-rial

Size, lo-cation

Progressing settle-ment that is ex-pected to degrade the embankment to reservoir level. RED

Downstream evacuation. Utilize all available equip-ment and personnel to build up the crest in the area that is settling. Iden-tify any boils near settle-ment points for flowing material and pursue action for boils.

Dozer, shovels, source of fill mate-rial, sand-bags

Size, lo-cation

Cra

ck

ing

Cracks in the em-bankment crest or on slopes.

BLUE Walk on entire crest and slope and check for addi-tional cracking.

Stakes, tape measure

Size, lo-cation

Numerous cracks in crest that are en-larging, especially those perpendicu-lar to the centerline of the dam.

BLUE

Initiate 24-hour surveil-lance. Carefully monitor and measure cracking to determine the speed and extent of the problem. Mo-bilize to fill cracks. Cracks parallel to the centerline in-dicate a slide. Follow reme-dial action for slides.

Stakes, tape measure, dozer, shovels, source of fill mate-rial

Size, lo-cation

Large cracks in the crest that are rap-idly enlarging, es-pecially those per-pendicular

ORANGE

Continue monitoring and remedial action as de-scribed above.


Size, lo-cation




Specific

observation

Emergency condition

level


material, and sup-

plies

Data to record

to the centerline of the dam.

Cracking that ex-tends to pool eleva-tion. RED

Downstream evacuation. Continue remedial actions as described above.


Size, lo-cation

Cra

ck

ing

or

mo

vem

en

t o

f co

ncre

te s

tru

ctu

re

Minor cracking and/or movement.

BLUE

Immediately install meas-uring device to monitor movement.

Crack Moni-tors, stakes, tape measure

Size, lo-cation

Significant crack-ing and/or move-ment.

BLUE

Initiate 24-hour surveil-lance. Lower burlap on up-stream face of crack to re-duce flow of soil particles. Dump large rock on down-stream of moving concrete structure monolith to resist the movement.

Burlap, rock, dozer, shovels

Size, lo-cation, flow rate

Serious cracking and/or movement

ORANGE

Prepare for evacuation. Continue monitoring and remedial action as de-scribed above.

Dozer, rock, burlap, crack monitors

Size, move-ment, flow rate

Major cracking and/or movement

RED

Downstream evacuation. Dam failure is imminent. Continue monitoring and remedial actions as de-scribed above.

Dozer, shovels, rock


Up

stre

am

wh

irlp

oo

l

Whirlpool in the lake in the vicinity of the embank-ment

RED

Downstream evacuation. Attempt to plug the en-trance of the whirlpool with riprap from the slope of the embankment. Search downstream for an exit point and construct a ring dike to retard the flow of soil particles.

Dozer, fill mate-rial, sand-bags, fil-ter cloth, straw, rocks





Specific

observation

Emergency condition

level


material, and sup-

plies

Data to record

Malf

un

cti

on

of

gate

Structural member of a gate or gate operator broken or severely damaged so as to prevent op-eration of the gate

ORANGE

Initiate 24-hour surveil-lance. Immediately place stop logs in front of gate and initiate necessary ac-tions to get gate repaired.

Crane and welder

Type of prob-lem, lo-cation

Rap

idly

ris

-

ing

lak

e

Lake level rising and rain continu-ing BLUE

Initiate 24-hour surveil-lance of lake level and rain-fall.

Generate inflow forecasts every 12 hours.

Lake level, rainfall

Ove

rto

pp

ing

Water flowing over the dam and lake continuing to rise. No significant ero-sion of down-stream embank-ment.

ORANGE

Prepare for evacuation. Continue monitoring.

Generate inflow forecasts every 3 hours.

Dozer, fill mate-rial, sand-bags, fil-ter cloth, rocks

Lake level, rainfall

Water flowing over the dam, the lake continuing to rise, and significant erosion of down-stream embank-ment with develop-ment of head-cuts encroaching on the dam crest, or sig-nificant movement of sections of con-crete or masonry portions of the dam.

RED

Immediate evacuation. Dam failure is imminent or ongoing.

Cam-eras.

Status of breach for-mation. Width of breach as it en-larges.

A 2.3 Roles and Responsibilities of Dam Authorities during Emergency

Responsibilities of Dam Executive Engineer



➢ Responsible for init iat ing implementation of the EAP.

➢ Collecting weather forecasts and the inflow forecasts and alerting

of any potential emergency situation.

➢ Conducting routine dam maintenance, such as annual weed con-

trol , conducting dam integrity inspections, and not ifying Karna-

taka Water Resources Department of any potential emergency

situations.

➢ Contacting emergency personnel should a dam fai lure be imminent.

Responsibilities of Dam Superintending Engineer

➢ Responsible for updating the EAP. An annual EAP re-view will be conducted to ensure that contact n ames and numbers are current on the Notification Flowcharts.

Responsibilities of Dam Chief Engineer

➢ Responsible for direct ing specif ic , incident appropri-ate actions during an emergency, such as opening or closing water outlets and remedial construction activi-t ies such as earth moving, etc. Specific scenarios are not listed in this EAP.

➢ For inspect ing the dam in a potential emergency such as the potent ial threat of high waters or a t ropical cy-clone. The Chief Engineer will contact the Hassan Dis-trict Pol ice and Distr ict Deputy Commissioner.

➢ If warranted, the Chief Engineer will notify the State and Distric t Disaster Management Authori t ies. The Hassan District Police will not i fy downst ream residents. The Hassan district deputy commissioner will implement the Notif icat ion Flowchart for regional and s tate dis-aster management contacts .

➢ In the event of a fa i lure condition , the Chief Engineer will activate the Emergency Operations Center to serve as the main distribution center for warning and evacu-ation activities . The Emer gency Operations Center will be established at the Office of Karnataka Water Resources Department. The Chief Engineer will be responsible for init iating actions from this loca-tion.

A 2.4Sample Public Announcements

Note: These messages are communicated to downstream residents to alert the public of impending danger. The Karnataka Water Resources



Department should coordinate with the India Mete orological Department, the Hassan Disaster Management Authori ty, and the Distric t Magistrate Hassan & Mandya Districts prior to release. Messages can be communicated via radio, televis ion, bulk SMSs of local mobile networks, and other media outlets.

Announcement for a Slowly Developing “Watch” Condition ( BLUE Emer-gency Level)

Karnataka Water Resources Department has declared a BLUE Level “Watch” condit ion for Hemavathy Dam, Project Ident ification Code KA06HH0117 as of [t ime and date] . [Briefly describe the problem or con-dition.] Although there is no immediate danger of the dam failing, [De-scribe what ac tions are being taken to monitor and control the s i tua tion.] [S ta te the quanti ty o f any re leases from the reservoir . ]

Announcement for a Worsening “Watch” Con dition (BLUE Emergency Level)

Karnataka Water Resources Department has declared a BLUE Level “Watch” condition for Hemavathy Dam, Project Identi fication Code KA06HH0117 as of [time and date] . [Brief ly describe the problem or con-dition.] Although there is no immediate danger of the dam fai ling a possi-bili ty now exist s that the dam wil l fai l i f correct ion efforts are unsuccessful . [Describe what act ions are being tak en to monitor and correct the s i tuat ion .] [State the quant i ty of any re leases from the reservoir] . Addi t ional news will be made available as soon as i t is received.

Announcement for a Probable “Failure” Condition ( ORANGE Emergency Level)

Urgent! This is an emergency message. Karnataka Water Resources Depart-ment has announced that Hemavathy Dam, Project Ident ification Code KA06HH0117 is probably going to fai l . [Describe what actions are being taken to monitor and control the s ituation.] I t is possible that the dam wil l fail in [##] hours . Residents of vil lages in nearby low lying areas along the Hemavathy River , as well as the town of Holenarasipur , should prepare for immediate evacuation. Additional news will be made available as soon as i t is received.

Announcement of an Impending “Failure” Condition ( RED Emergency Level)

Emergency! This is an emergency message. Hemavathy Dam, Project Identif ication Code KA06HH0117 is going to fail at any moment. Resi-dents who have not yet done so should immediately evacuate the town of Holenarasipur and lowlying vi llage areas along the Hemavathy River. The flood waters have already reached [Highway] and [Road] . Addit ional news will be made available as soon as i t is received.

Announcement of an Ongoing “Failure” Condition (RED Emergency Level)

Emergency! This is an emergency message. Hemavathy Dam, Project Identif ication Code KA06HH0117 failed at [time and date] . Residents who have not yet done so should immediately evacuate the town of Holenarasipur and low-lying vil lage areas along the Hemavathy River. The



flood waters have already reached [Highway] and [Road]. Additional news will be made available as soon as i t is received.

APPENDIX III ― MATERIAL REQUIRED FOR MAINTE-

NANCE DURING MONSOON Materials during monsoon period should be stocked in adequate quantity as experience shows them to be necessary. Particular care should be taken that the required materials are distributed with careful fore-thought so as to be readily available everywhere, particu-larly at dangerous sites. The quantity of materials required depends on importance or dan-gerousness of the dam and the distances of the dam from the nearest stations at which these can be purchased. This will need to be worked out by the respective dam owners / state govt. as per their experience & documented in the O & M Manual for the dams. The following norms have been prescribed by the Govt. of Madhya Pradesh for their projects during monsoon period.

1. Patrolling

i. Torches: 1 for each Executive Engineer, Assistant Engineer, Sub-Engineer and 2 in spare.

ii. Cells: 1fill and 2 spare sets

iii. Binoculars 6

iv. Night Vision Goggles 2

v. Dragon Lights 10

vi. Search Lights 15

vii. Communication Systems (local walkie-talkie) 8

viii. Rain coat: 20

ix. Gum boots: 20

x. Danger Zone Light: Strips 10

xi. Flares 50

2. Leaks

i Gunny Bags 500

ii. Stakes 60 to 120 stakes per km.

iii. Baskets 1 Basket of toot per beldar &one spare. iv. Sutli (Twine) 0.5kg per 100bags

v. Needles ½ dozen with each work mestry

vi. Sand Collection of 2 to 4m3every km. for





APPENDIX IV― SCHEDULED OR UNSCHEDULED DAM

SAFETY INSPECTION FORM

A form designed for use during scheduled dam safety inspections – which includes pre- and

post-monsoon inspections – follows. The form contains a comprehensive checklist (Part 2a) of

items that are found at dams that need to be evaluated during a safety inspection. The checklist

consists of (1) a series of questions that need to be answered as Yes/No/Not Applicable for

each inspection item, (2) a remarks box in which critical aspects can be commented upon

following each question, and (3) a final condition assessment

(Unsatisfactory/Poor/Fair/Satisfactory) for that inspection item. Not all inspection items will be

found at a dam. The form concludes with a Consolidated Dam Health Status Report (Part 2b).



Scheduled / Unscheduled Dam Safety Inspection Form

Part 1a - Inspection Details:

Dam Name: Project ID Code

(PIC):

Dam Type: Dam Purpose:

Dam Owner: Hazard Classification:

Dam Operator: Inspection by:

City/State/PIN: Date of Inspection:

District: Reservoir Level:

Latitude: Auxiliary Spillway

Level:

Longitude: Weather Conditions:

Part 1b - Inspection Remarks:

Please provide any additional information or comments not covered by Part 1a form above.



Part 2a - Inspection Checklist:

SN Inspection Item Responsea Remarks Conditionb

Y N NA

A Reservoir

A1.1 General Condition

Un

satisfactory/

Po

or/

Fair/

Satisfacto

ry

1.1.1 Is the reservoir water level unusually high

or low?

1.1.2 Are there signs of decline in water quality?

1.1.3 Are there signs of recent sediment deposi-

tion?

1.1.4 Is floating debris present?

1.1.5 Are there people or livestock in and around

reservoir?

1.1.6 Any other issues?

B Dam and Dam Reach (Embankment)

B1.1 General Condition

1.1.1 Any major alterations or changes to the

dam since the last inspection?

1.1.2 Is there any new nearby development in the




downstream floodplain?

1.1.3 Any misalignment of poles, fencing or walls

due to dam movement?

B1.2 Upstream Slope

1.2.1 Any signs of bulging or concavity (depres-

sions)?

1.2.2 Presence of longitudinal or transverse

cracks?

1.2.3 Any signs of distress to the stability of

slopes?

1.2.4 Any other signs of structural distress or in-

stability?

1.2.5 Trees or profuse growth of weeds/bushes

at any location?

1.2.6 Is there evidence of livestock on the

upstream slope?

1.2.7 Are ants, termites, crabs or other burrow-

ing animals present?

1.2.8 Any degradation to slope protection (rip-

rap)?





B1.3 Crest of Dam

1.3.1 Any signs of excessive or uneven settle-

ment?


cracks?

1.3.3 Presence of undulations, local depressions

or heaving?

1.3.4 Any degradation to access road (sealed/un-

sealed)?

1.3.5 Evidence of livestock on dam crest?


at any location?

1.3.7 Any degradation to edges of dam crest or

reduction in width?

1.3.8 Any degradation to upstream parapet or

downstream curb wall?


B1.4 Downstream Slope




1.4.1 Any signs of bulging or concavity (depres-

sions)?

1.4.2 Any wet patches (seepage), concentrated

leaks or evidence of boiling?


cracks?

1.4.4 Any signs of distress to the stability of

slopes?

1.4.5 Are of rain cuts/erosion channels present

at any location?

1.4.6 Any other signs of structural distress or in-

stability?


at any location?

1.4.8 Is there evidence of livestock on the

downstream slope?

1.4.9 Are ants, termites, crabs or other burrow-

ing animals present?

1.4.10 Any other degradation to slope protection

(turfing)?





B1.5 Breaching Section

1.5.1 Any difficulties in accessing the breaching

section?

1.5.2 Evidence of recent degradation?


B1.6 Junction with Masonry/Concrete Dam Section

1.6.1 Any presence of leaks, springs or wet spots

in the vicinity of the junction?

1.6.2 Any presence of cracking, settlement or up-

heaval of earthwork?

1.6.3 Any evidence of erosion or slope instabil-

ity?


B1.7 Abutment Contacts


in the vicinity of the abutment?

1.7.2 Any presence of cracking, settlement or up-

heaval of earthwork?

1.7.3 Any evidence of erosion or slope




instability?

1.7.4 Trees or profuse growth of weeds/bushes?

1.7.5 Any degradation to up/downstream slope

protection (rip-rap, turfing)?


B2 Dam and Dam Block/Reach (Concrete/Masonry)

B2.1 General Condition

2.1.1 Any major alterations or changes to the

dam since the last inspection?

2.1.2 Is there any new nearby development in the

downstream floodplain?

2.1.3 Any misalignment of poles, fencing or walls

due to dam movement?

B2.2 Upstream Face

2.2.1 Evidence of surface defects (honeycomb-

ing, staining, stratification)?

2.2.2 Concrete/masonry deterioration (spalling,

leaching, disintegration)?

2.2.3 Is cracking present (structural, thermal,




along joints)?

2.2.4 Evidence of differential settlement (dis-

placed/offset/open joints)?

2.2.5 Presence of vegetation (growth in joints be-

tween blocks)?

2.2.6 Evidence of any other damage to joints

and/or waterstops?


B2.3 Crest of Dam



2.3.2 Presence of cracking (structural, thermal,

along joints)?

2.3.3 Profuse growth of weeds/grass/plants at

any location?

2.3.4 Any degradation to access road?

2.3.5 Any degradation to upstream parapet or

downstream curb wall?





B2.4 Downstream Face

2.4.1

Evidence of surface defects (honey-comb-





along joints)?




tween blocks)?


and/or waterstops?

2.4.7 Excessive seepage/sweating at any location

on downstream face?

2.4.8 Significant leakage at any location on

downstream face?


B2.5 Abutment Contacts


in vicinity of abutment?




2.5.2 Any presence of cracking or settlement?

2.5.3 Profuse growth of weeds/grass/plants at

any location?


C1 Gallery/Shaft and Drainage (Embankment)

C1.1 General Condition

1.1.1 Slushy condition or water logging immedi-

ately downstream of dam?

1.1.2 Any evidence of boiling in vicinity of dam

toe?

C1.2 Gallery/Shaft Condition

1.2.1 Any problems accessing or inspecting gal-

lery/shaft (obstruction)?

1.2.2 Any safety issues (inadequate handrails,

lighting or ventilation)?

1.2.3 Problems of inadequate drainage (slippery

stairs, water logging of gallery)?







along gallery/shaft?

1.2.6 Significant leakage at any location along

gallery/shaft?


C1.3 Drain Condition

1.3.1 Is the flow in the drain unusually high or

low?

1.3.2 Any reduction/deterioration in the drain

section or slope?

1.3.3 Presence of debris or profuse growth of

weeds/bushes at any location?

1.3.4 Any other obstruction to the flow of the

drain?

1.3.5 Is the flow in the drain noticeably spo-

radic/irregular?

1.3.6 Does the drainage water have high turbidity

(high sediment load)?


C2 Gallery/Shaft and Drainage (Concrete/Masonry)




C2.1 General Condition

2.1.1 Slushy condition or water logging just

downstream of dam?

C2.2 Gallery/Shaft Condition

2.2.1 Any problems accessing or inspecting gal-

lery/shaft (obstruction)?

2.2.2 Any safety issues (inadequate handrails,

lighting or ventilation)?

2.2.3 Problems of inadequate drainage (slippery

stairs, water logging of gallery)?






along joints)?




and/or waterstops?





along gallery/shaft?

2.2.10 Significant leakage at any location along

gallery/shaft?


C2.3 Drain Condition

2.3.1 Is the flow in the drain unusually high or

low?

2.3.2 Presence of calcium or other deposits in

drain?

2.3.3 Any other evidence of the drain being

blocked/having reduced section?

2.3.4 Is the flow in the drain noticeably spo-

radic/irregular?

2.3.5 Does the drainage water have unusual color

(leachate)?





D1 Spillway and Energy Dissipation Structure

1.1 Spillway

1.1.1 Any problems inspecting spillway (ob-

structed access, damaged catwalk)?

1.1.2 Any obstructions in or immediately down-

stream of the spillway?

1.1.3 Evidence of abrasion, cavitation or scour

on glacis (e.g. exposed reinforcement)?

1.1.4 Presence of displaced, offset or open

joints?


along joints)?






tween blocks)?


and/or water stops?





on spillway glacis?

1.1.11 Significant leakage at any location on spill-

way glacis?


D1.2 Energy Dissipation Structure

1.2.1 Any problems inspecting energy dissipation

structure?

1.2.2 Any obstructions in or immediately down-

stream of dissipation structure?


on dissipation structure?

1.2.4 Presence of displaced, offset or open

joints?


along joints)?





1.2.8 Presence of vegetation (growth in joints




between blocks)?


and/or waterstops?

1.2.10 Any problems with under-drainage (block-

age of open drain holes)?


E1 Intake/Outlet and Water Conveyance Structure

E1.1 Intake/Outlet Structure

1.1.1 Any problems inspecting intake/outlet

structure (obstructed/unsafe access)?

1.1.2 Any obstructions in, upstream or down-

stream of intake/outlet structure?


on intake/outlet structure?

1.1.4 Any evidence of structural distress (dis-

placed/offset/open joints, cracking)?

1.1.5 Any evidence of surface defects and/or

concrete/masonry deterioration?





E1.2 Water Conveyance Structure

1.2.1 Any problems inspecting intake/outlet

structure (obstructed/unsafe access)?

1.2.2 Any obstructions in, upstream or down-

stream of water conveyance structure?


on structure?

1.2.4 Any evidence of structural distress (dis-

placed/offset/open joints, cracking)?

1.2.5 Any evidence of surface defects and/or

material deterioration?

1.2.6 Any evidence of seepage or leakage from

water conveyance structure?


F1 Hydro-Mechanical Component and Turbine/Pump

F1.1 Gates, Stop Logs and Bulk Heads

1.1.1 Any problems inspecting gate/stop

log/bulk head (obstructed/unsafe access)?

1.1.2 Any issues with storage of equipment

(emergency stop logs, and gate leaves)?




1.1.3 Missing or inadequate spare parts (particu-

larly requiring regular replacement)?

1.1.4 Any deterioration of equipment (connect-

ing bolts, welds, surface, paint work?)

1.1.5 Any obstructions preventing or impairing

smooth operation?

1.1.6 Any problems with the rollers (not touch-

ing tracks, inadequate lubrication)?

1.1.7 Any problems with the seals (damage,

weathering, gaps with bearing surface)?


F1.2 Hoists, Cranes and Operating Mechanisms

1.2.1 Any problems inspecting hoist/crane/op-

erating mechanism?





1.2.4 Any wear or damage to wire cables and

other moving parts?





smooth operation?

1.2.6 Missing or inadequate provision of back-

up/standby power supply?

1.2.7 Any health and safety concerns (e.g. lack of

"danger" sign during maintenance)?


F1.3 Valves

1.3.1 Any problems inspecting valve?


smooth operation?

1.3.3 Any deterioration of valve and associated

equipment?


F1.4 Trash Racks

1.4.1 Any problems inspecting trash rack?

1.4.2 Problems of excessive debris and/or inade-

quate cleaning?




1.4.3 Any deterioration of trash rack (rust, corro-

sion, and damaged blades)?


F1.5 Trash Rack Cleaning Machines

1.5.1 Any problems inspecting trash rack clean-

ing machine?





1.5.4 Any wear or damage to wire cables and

other moving parts?


smooth operation?

1.5.6 Missing or inadequate provision of back-

up/standby power supply?

1.5.7 Any health and safety concerns (e.g. lack of

"danger" sign during maintenance)?


F1.6 Turbines




1.6.1 Any problems inspecting turbine?


smooth operation?

1.6.3 Any deterioration of turbine, blades and as-

sociated equipment?


F1.7 Pumps

1.7.1 Any problems inspecting pump?


smooth operation?

1.7.3 Any deterioration of pump and associated

equipment?


G1 Access Road

G1.1 General Condition

1.1.1 Any problems ensuring security of dam site

(including gates and fencing)?

1.1.2 Any obstructions along or at entrance to

access road (temporary or long-term)?




1.1.3 Any slope stability issues (road embank-

ment or adjacent slopes)?

1.1.4 Profuse growth of weeds/grass on or in vi-

cinity of access road?

1.1.5 Any drainage problems (standing water on

or adjacent to road)?

1.1.6 Any other degradation to road surface

(ruts, potholes, cavities, cracking)?


H1 Instrumentation

H1.1 General Condition

1.1.1 Any problems inspecting instrument (ob-

structed/unsafe access)?

1.1.2 Is the instrument vulnerable to damage or

theft (inadequate protection)?

1.1.3 Any problems ensuring correct functioning




of instrument (lighting, ventilation)?

1.1.4 Any evidence of degradation to condition

of instrument (rusting, vandalism)?

1.1.5 Any evidence of instrument not working

(decommissioned, broken)?


I1 OtherAppurtenant Structures (Flexi-Component)

I1.1 Bridges and Catwalks

1.1.1 Any problems inspecting bridge or catwalk

(obstructed/unsafe access)?

1.1.2 Any security issues relating to unauthorized

access (e.g. for gate operation)?

1.1.3 Are the decking, girders and supports

structurally sound?

1.1.4 Any evidence of defects or deterioration of

steel, concrete or paint work?


I1.2 Guide Walls

1.2.1 Any problems inspecting guide wall




(obstructed/unsafe access)?

1.2.2 Any problem with drainage from behind

wall (e.g. blocked weep holes)?

1.2.3 Any evidence of scour, foundation erosion

or undercutting?

1.2.4 Any signs of differential settlement, crack-

ing or tilting?


I1.3 Miscellaneous

1.3.1 Any other issues? (please specify part)

J1 Emergency Preparedness

J1.1 Emergency Action Plan

1.1.1 Is the Emergency Action Plan (EAP) still

pending, inadequate or outdated?

1.1.2 If not, are any dam staff unaware or insuffi-

ciently conversant with the EAP?

1.1.3 Any concerned authorities unaware or in-

sufficiently conversant with the EAP?

1.1.4 Do the communication directories/contact




details require updating?

1.1.5 Any problems accessing or operating the

communication/warning system?


aRespond either yes (Y), no (N) or not applicable (NA).

bCondition: Please rate the condition as either Satisfactory, Fair, Poor or Unsatisfactory as described below:

1. Satisfactory - No existing or potential dam safety deficiencies are recognized. Acceptable performance is expected under all loading condi-

tions (static, hydrologic, seismic) in accordance with the applicable regulatory criteria or tolerable risk guidelines.

2. Fair - No existing dam safety deficiencies are recognized for normal loading conditions. Rare or extreme hydrologic and/or seismic events

may result in a dam safety deficiency. Risk may be in the range to take further action.

3. Poor - A dam safety deficiency is recognized for loading conditions which may realistically occur. Remedial action is necessary. Poor may also

be used when uncertainties exist as to critical analysis parameters which identify a potential dam safety deficiency. Further investigations and

studies are necessary.

4. Unsatisfactory - A dam safety deficiency is recognized that requires immediate or emergency remedial action for problem resolution.



Part 2b – Consolidated Dam Health Status Report:

SN Observations/Significant

Deficiencies Noticed Remedial Measures Suggested Categorya

1

2

3

4

aCategory I – deficiencies which may lead to failure; Category II – major deficiencies requiring prompt remedial measures; Category III – minor

remedial measures which are rectifiable during the year



APPENDIX V - GLOSSARY

Dam – any artificial barrier including

appurtenant works constructed across

rivers or tributaries thereof with a view

to impound or divert water; includes

barrage, weir and similar water im-

pounding structures but does not

include water conveyance structures

such as canal, aqueduct and navigation

channel and flow regulation structures

such as flood embankments, dikes, and

guide bunds.

Dam failure – failures in the struc-

tures or operation of a dam which may

lead to the uncontrolled release of im-

pounded water resulting in down-

stream flooding affecting the life and

property of the people.

Dam incident – all problems occur-

ring to a dam that has not degraded

into ‘dam failure’ and including the fol-

lowing:

a) Structural damage to the dam and

appurtenant works;

b) Unusual readings of instruments

in the dam;

c) Unusual seepage or leakage

through the dam body;

d) Change in the seepage or leakage

regime;

e) Boiling or artesian conditions no-

ticed below an earth dam;

f) Stoppage or reduction in seepage

or leakage from the foundation or

body of the dam into any of the

galleries, for dams with such gal-

leries;

g) Malfunctioning or inappropriate

operation of gates;

h) Occurrence of any flood, the peak

of which exceeds the available

flood discharge capacity or 70% of

the approved design flood;

i) Occurrence of a flood, which re-

sulted in encroachment on the

available freeboard, or the

adopted design freeboard;

j) Erosion in the near vicinity, up to

five hundred meters, downstream

of the spillway, waste weir, etc.;

and

k) Any other event that prudence

suggests would have a significant

unfavorable impact on dam

safety.



Dam inspection – on-site visual ex-

amination of all components of dam

and its appurtenances by one or more

persons trained in this respect and in-

cludes investigation of the non-over-

flow portion, spillways, abutments,

stilling basin, piers, bridge, down-

stream toe, drainage galleries, opera-

tion of mechanical systems (including

gates and its components, drive units,

cranes), interior of outlet conduits, in-

strumentation records, and record-

keeping arrangements.

Dam owner – the Central Govern-

ment or a State Government or public

sector undertaking or local authority or

company and any or all of such per-

sons or organizations, who own, con-

trol, operate or maintain a specified

dam.

Dam safety – the practice of ensuring

the integrity and viability of dams such

that they do not present unacceptable

risks to the public, property, and the

environment. It requires the collective

application of engineering principles

and experience, and a philosophy of

risk management that recognizes that a

dam is a structure whose safe function

is not explicitly determined by its orig-

inal design and construction. It also in-

cludes all actions taken to identify or

predict deficiencies and consequences

related to failure, and to document,

publicize, and reduce, eliminate, or re-

mediate to the extent reasonably pos-

sible, any unacceptable risks.

Decommission― Taking a dam out

of service in an environmentally sound

and safe manner or converting it to an-

other purpose.

Design life― the intended period that

the dam will function successfully with

only routine maintenance; determined

during design phase.

Distress condition – the occurrence

or potential development of such con-

ditions in the dam or appurtenance or

its reservoir or reservoir rim, which if

left unattended to, may impede the

safe operation of dam for its intended

benefits or may pose unacceptable

risks to the life and property of people

downstream.

Documentation – all permanent rec-

ords concerning investigation, design,

construction, operation, performance,



maintenance and safety of dams and

includes design memorandum, con-

struction drawings, geological reports,

reports of specialized studies simulat-

ing structural and hydraulic response

of the dam, changes made in design

and drawings, quality control records,

emergency action plan, operation and

maintenance manual, instrumentation

readings, inspection and testing re-

ports, operational reports, and dam

safety review reports;

Emergency Action Plan (EAP)― a

plan of action to be taken to reduce the

potential for damage to property and

loss of life in the area affected by fail-

ure of a dam or other potentially haz-

ardous practice.

Hazard Classification― a system

that categorizes dams according to the

degree of adverse incremental conse-

quences of a failure or improper oper-

ation of the dam. CWC classifies dam

hazards as “low”, “significant”, or

“high”.

Maintenance― the recurring activi-

ties necessary to retain or restore a

dam in a safe and functioning condi-

tion, including the management of

vegetation, the repair or replacement

of failed components, the prevention

or treatment of deterioration, and the

repair of damages caused by flooding

or vandalism.

Operation― the administration, man-

agement, and performance of mainte-

nance activities necessary to keep a

dam safe and functioning as planned.

Program ― any authorized activity

used to implement and carry out goals,

actions, and objectives contained

within the authorizing legislation.

Program Life― the period in a con-

tract, conservation plan, or plan during

which the conservation practice or

conservation system shall be main-

tained and used for the intended pur-

pose; determined by program require-

ments.

Rehabilitation― the completion of

all work necessary to extend the ser-

vice life of the practice or component

and meet applicable safety and perfor-

mance standards.

Repair― actions to restore deterio-

rated, damaged, or failed damor its



component to an acceptable by meet-

ing functional condition.

Replacement― the removal of a

structure or component and installa-

tion of a similar, functional structure

or component.

Service Life― the actual period after

construction of a dam, during which

the practice functions adequately and

safely with only routine maintenance;

determined by on-site review.

Abutment―that part of a valley side

against which a dam is constructed.

Right and left abutments are those on

respective sides of the of an observer

looking downstream.

Air-Vent Pipe―a pipe designed to

provide air to the outlet conduit to re-

duce turbulence during release of wa-

ter and safeguard against damages due

to cavitation.

Appurtenant Structures―ancillary

features of a dam, such as the outlet,

spillway, energy dissipation arrange-

ment powerhouse, tunnels, etc.

Arch Dam―a concrete or masonry

dam that is curved to transmit the

major part of the water pressure to the

abutments.

Backwater Curve―the longitudinal

profile of the water surface in an open

channel where the depth of flow has

been increased by an obstruction, an

increase in channel roughness, a de-

crease in channel width, or a flattening

of the bed slope.

Base Width (Base Thickness) ―the

maximum width or thickness of a dam

measured horizontally between up-

stream and downstream faces and nor-

mal (perpendicular) to the axis of the

dam but excluding projections for out-

lets, etc.

Berm―a horizontal step or bench in

the sloping profile of an embankment

dam.

Upstream Blanket―an impervious

layer placed on the reservoir floor up-

stream of a dam. In case of an embank-

ment dam, the blanket may be

connected to the impermeable element

in a dam.

Buttress dam―a dam consisting of a

watertight upstream face supported at



intervals on the downstream side by a

series of buttresses.

Cofferdam―a temporary structure

enclosing all or part of a construction

area so that construction can proceed

in a dry area.

Concrete Lift―in concrete works the

vertical distance between successive

horizontal construction joints.

ConduitOutlet Works―a closed con-

duit for conveying discharge through

or under a dam for different project

purposes.

Consolidation Grouting (Blanket

Grouting) ―the injection of grout to

consolidate a layer of the foundation,

resulting in greater impermeability,

strength, or both.

Construction Joint―the interface be-

tween two successive placings or pours

of concrete where a bond, not perma-

nent separation, is intended.

Core Wall―a wall built of impervious

material, usually concrete or asphaltic

concrete, in the body of an embank-

ment dam to prevent leakage.

Crest Length―the length of the dam

at its crest (dam top) top of a dam,

including the length of the spillway,

powerhouse, navigation lock, fish

pass, etc., where these structures form

part of the length of a dam. If detached

from a dam, these structures should

not be included.

Crest of dam―Used to indicate the

“top of dam”. To avoid confusion to

indicate the crest of spillway and top of

dam may be used.

Culvert―a drain or waterway built un-

der a road, railway, or embankment,

usually consisting of a pipe or covered

conduits

Cutoff―an impervious construction

or material which reduces seepage

through the foundation material.

Cutoff trench―an excavation later to

be filled with impervious material to

form a cutoff.

Cutoff wall―a wall of impervious ma-

terial (e.g., concrete, asphaltic con-

crete, steel-sheet piling) built into the

foundation to reduce seepage under

the dam.

Dead storage―the storage that lies

below the invert of the lowest outlet



and that, therefore, cannot be with-

drawn from the reservoir.

Design flood―see spillway design

flood.

Diaphragm―see membrane.

Dike (Levee)―a long low embank-

ment whose height is usually less than

5 m and whose length is more than 10

times the maximum height. Usually ap-

plied to embankments or structures

built to protect land from flooding. If

built of concrete or masonry, the struc-

ture is usually referred to as a flood wall.

Also, used to describe embankments

that block areas on a reservoir rim that

are lower than the top of the main dam

and that are quite long. In the Missis-

sippi River basin, where the old French

word levee has survived, the term now

applies to flood-protecting embank-

ments whose height can average up to

15 m.

Diversion channel, canal, or tun-

nel―a waterway used to divert water

from its natural course. These terms

are generally applied to temporary

structures such as those designed to

bypass water around a dam site during

construction. “Channel’ is normally

used instead of “canal” when the wa-

terway is short.Occasionally these

terms are applied to permanent struc-

tures.

Drainage area―an area that drains

naturally to a point on a river.

Drainage layer or blanket―a layer of

permeable material in a dam to relieve

pore pressure or to facilitate drainage

of fill.

Relief well―vertical wells or bore-

holes, constructed downstream of an

embankment dam to relieve the pres-

sure from confined pervious layers in

foundation overlaid by an impervious

layer to arrest boiling.

Drawdown―the lowering of water

surface level due to release of water

from a reservoir.

Earthen dam or earth filleddam―see

embankment dam.

Embankment dam (Fill dam) ― any

dam constructed of excavated natural

materials.

Earth dam (Earth fill dam) ―An

embankment dam in which more than

50 percent of the total volume is



formed of compacted fine-grained ma-

terial obtained from a borrow area.

Homogeneous earth filldam― an

embankment dam constructed of sim-

ilar earth material throughout, except

internal drains or drainage blankets;

distinguished from a zoned earth fill

dam.

Hydraulic fill dam―an embankment

dam constructed of materials, often

dredged, that are conveyed and placed

by suspension in flowing water.

Rock fill dam―an embankment dam

in which more than 50 percent of the

total volume comprises compacted or

dumped pervious natural or crushed

rock.

Rolled fill dam―an embankment

dam of earth or rock in which the ma-

terial is placed in layers and compacted

using rollers or rolling equipment.

Zoned embankment dam―an em-

bankment damcomposed of zones of

materials selected for different degrees

of porosity, permeability and density.

Emergency spillway―see spillway.

Face―the external surface of a struc-

ture, e.g., the surface of a wall of a dam.

Failure―the uncontrolled release of

water from a dam.

Filter (filter zone) ―A band or zone

of granular material that is incorpo-

rated into a dam and is graded (either

naturally or by selection) to allow seep-

age to flow across or down the filter

without causing the migration of ma-

terial from zones adjacent to it.

Flashboards―a length of timber,

concrete, or steel placed on the crest of

a spillway to raise the retention water

level but that may be quickly removed

in the event of a flood, either by a trip-

ping device or by deliberately designed

failure of the flashboard or its sup-

ports.

Floodplain―an area adjoining a body

of water or natural stream that has

been, or may be, covered by flood wa-

ter.

Floodplain management―a man-

agement program to reduce the conse-

quences of flooding, either by natural

runoff or by dam failure, to existing

and future properties in a floodplain.

Flood routing―the determination of

the attenuating effect of storage on a



flood passing through a valley, chan-

nel, or reservoir.

Flood surcharge―the volume or

space in a reservoir between the con-

trolled retention water level (Full Res-

ervoir Level) and the maximum water

level. Flood surcharge cannot be re-

tained in the reservoir but will flow

over the spillway until the controlled

retention water level is reached.

Flood wall―a concrete wall con-

structed adjacent to a stream to pre-

vent flooding of property on the land-

ward side of the wall, normally con-

structed in lieu of or to supplement a

levee where the land required for levee

construction is expensive or not avail-

able.

Foundation of dam―the natural ma-

terial on which the dam structure is

placed.

Freeboard―the vertical distance be-

tween a stated reservoir level and the

top of a dam. Normal freeboard is the

vertical distance between Full Reser-

voir Level (FRL) and the top of the

dam. Minimum freeboard is the

vertical distance between the

Maximum Water Level (MWL) and

the top of the dam.

Gallery―(a) a passageway within the

body of a dam or abutment, hence the

terms grouting gallery, inspection gal-

lery and drainage gallery (b) along and

rather narrow hall, hence the following

terms for a power plant viz. valve gal-

lery, transformer gallery and bus bar

gallery.

Gate―a device in which a leaf or

member is moved across the waterway

from an external position to control or

stop the flow.

Bulkhead gate―a gate used either for

temporary closure of a channel or con-

duit to empty it for inspection or

maintenance or for closure against

flowing water when the head differ-

ence is small, e.g., for diversion tunnel

closure. Although a bulkhead gate is

usually opened and closed under

nearly balanced pressures, it neverthe-

less may be capable of withstanding a

high-pressure differential when in the

closed position.



Crest gate (spillway gate) ―a gate on

the crest of a spillway to control over-

flow or reservoir water level.

Emergency gate―a standby or re-

serve gate which is lowers only for re-

pairing / servicing of the service gate.

Fixed wheel gate (fixed-roller gate,

fixed-axle gate) ―a gate having

wheels or rollers mounted on the end

posts of the gate. The wheels move

against rails fixed in side grooves or

gate guides.

Flap gate―a gate hinged along one

edge, usually either the top or bottom

edge. Examples of bottom-hinged flap

gates are tilting gates and belly gates, so

called due to their shape in cross-sec-

tion.

Flood gate―a gate to control flood

release from a reservoir.

Guard gate (guard valve) ―a gate or

valve that operates fully open or

closed. It may function as a secondary

device for shutting off the flow of wa-

ter in case the primary closure device

becomes inoperable but is usually op-

erated under conditions of balanced

pressure and no flow.

Outlet gate―a gate controlling the

outflow of water from a reservoir.

Radial gate (Taintergate)―a gate

with a curved upstream plate and radial

arms hinged to piers or other support-

ing structures.

Service/Regulating gate (regulat-

ing valve) ―a gate or valve that oper-

ates under full pressure and flow to

throttle and vary the rate of discharge.

Slide gate (sluice gate) ―a gate that

can be opened or closed by sliding it in

supporting guides.

Gravity dam―a dam constructed of

concrete, masonry, or both that relies

on its weight for stability.

Grout cap―a pad or wall constructed

to facilitate pressure grouting of the

grout curtain beneath it.

Grout curtain (grout cutoff) ―a bar-

rier produced by injecting grout into a

vertical zone, usually narrow horizon-

tally, in the foundation to reduce seep-

age under a dam.

Height above lowest founda-

tion―the maximum height from the

lowest point of the general foundation

to the top of the dam.



Hydraulic height―the height to

which water rises behind a dam and

the difference between the lowest

point in the original streambed at the

axis of the dam and the maximum con-

trollable water surface.

Hydrograph―a graphic representa-

tion of discharge, stage, or other hy-

draulic property with respect to time

for a point on a stream. (At times the

term is applied to the phenomenon the

graphic representation describes;

hence a flood hydrograph is the pas-

sage of a flood discharge past the ob-

servation point.)

Inclinometer―an instrument, usually

consisting of a metal or plastic tube in-

serted in a drill hole and a sensitized

monitor either lowered into the tube

or fixed within it. The monitor

measures at different points the tube’s

inclination to the vertical. By integra-

tion, the lateral position at various lev-

els of the tube may be found relative

to a point, usually the top or bottom of

the tube, assumed to be fixed. The sys-

tem may be used to measure settle-

ment.

Intake―any structure in a reservoir,

dam, or river through which water can

be drawn into an aqueduct.

Internal Erosion―see piping.

Inundation map―a map delineating

the area that would be inundated in

case of a failure.

Leakage―Uncontrolled loss of water

by flow through a hole or crack.

Lining― a coating of asphaltic con-

crete, reinforced or unreinforced con-

crete, shotcrete, rubber or plastic on a

canal, tunnel etc. to provide water

tightness, prevent erosion, reduce fric-

tion, or support the periphery of struc-

ture. May also refer to lining, such as

steel or concrete, of outlet pipe or con-

duit.

Low-level outlet (bottom outlet)

―an opening at a low level from a res-

ervoir generally used for emptying or

for scouring sediment and sometimes

for irrigation releases.

Masonry dam―a dam constructed

mainly of stone, brick, or concrete

blocks that may or may not be joined

with mortar. A dam having only a



masonry facing should not be referred

to as a masonry dam.

Maximum cross-section of dam―a

cross-section of a dam at the point of

its maximum height.

Maximum water level―the maxi-

mum water level, including flood sur-

charge, the dam is designed to with-

stand.

Membrane (Diaphragm)―a sheet or

thin zone or facing made of a flexible

material, sometimes referred to as a di-

aphragm wall or diaphragm.

Minimum operating level―the low-

est level to which the reservoir is

drawn down under normal operating

conditions.

Morning glory spillway―see spillway.

Full Reservoir Level (FRL)/Nor-

mal water level―for a reservoir with

un-gated spillway it is the spillway crest

level. For a reservoir, whose outflow is

controlled wholly or partly by movable

gates, siphons or other means, it is the

maximum level to which water can be

stored under normal operating condi-

tions, exclusive of any provision for

flood surcharge.

One-Hundred Year (100-Year) Ex-

ceedance Interval― the flood magni-

tude expected to be equaled or ex-

ceeded on the average of once in 100

years. It may also be expressed as an

exceedance frequency, i.e. a percent chance

of being exceeded in any given year.

Outlet―an opening through which

water can be freely discharged from a

reservoir.

Overflow dam―a dam designed to be

overtopped.

Parapet Wall―a solid wall built along

the top of a dam for ornament, for the

safety of vehicles and pedestrians, or

to prevent overtopping.

Peak Flow―the maximum instanta-

neous discharge that occurs during a

flood. It coincides with the peak of a

flood hydrograph.

Pervious Zone―a part of the cross-

section of an embankment dam com-

prising material of high permeability.

Phreatic Surface―the top most flow

line in an embankment dam.

Piezometer―an instrument for meas-

uring pore water pressure within soil,

rock, or concrete.



Piping―the progressive development

of internal erosion by seepage, appear-

ing downstream as a hole or seam dis-

charging water that contains soil parti-

cles.

Pore Pressure―the interstitial pres-

sure of water within a mass of soil,

rock, or concrete.

Pressure Cell―an instrument for

measuring pressure within a mass of

soil, rock, or concrete or at an interface

between one and the other.

Pressure Relief Pipes―Pipes used to

relieve uplift or pore water pressure in

a dam’s foundation or structure.

Probable Maximum Flood

(PMF)―a flood that would result

from the most severe combination of

critical meteorologic and hydrologic

conditions possible in the region.

Probable Maximum Precipitation

(PMP)―the maximum amount and

duration of precipitation that can be

expected to occur on a drainage basin.

Pumped storage reservoir―a reser-

voir filled entirely or mainly with water

pumped from outside its natural drain-

age area.

Regulating dam―a dam impounding

a reservoir from which water is re-

leased to regulate

Reservoir area―the surface area of a

reservoir when filled to controlled re-

tention level.

Reservoir routing―the computation

by which the interrelated effects of the

inflow hydrograph, reservoir storage,

and discharge from the reservoir are

evaluated.

Reservoir surface―the surface of a

reservoir at any level.

Riprap―a layer of large stones, bro-

ken rock, or precast blocks placed ran-

domly on the upstream slope of an

embankment dam, on a reservoir

shore, or on the sides of a channel as a

protection against wave action. Large

riprap is sometimes referred to as ar-

moring.

Risk assessment―as applied to dam

safety, the process of identifying the

likelihood and consequences of dam

failure to provide the basis for in-

formed decisions on a course of ac-

tion.

Rock fill Dam―see embankment dam.



Roll Crete or Roller-Compacted

Concrete. Ano-slump concrete that

can be hauled in dump trucks, spread

with a bulldozer or grader, and com-

pacted with a vibratory roller.

Seepage―the interstitial movement of

water that may take place through a

dam, its foundation, or its abutments.

Sill―(a) A submerged structure across

a river to control the water level up-

stream. (b) The crest of a spillway. (c)

A horizontal gate seating, made of

wood, stone, concrete or metal at the

invert of any opening or gap in a struc-

ture, hence the expressions gate sill and

stop log sill.

Slope―(a) the side of a hill or moun-

tain. (b) The inclined face of a cutting

or canal or embankment. (c) Inclina-

tion from the horizontal. In the United

States, it is measured as the ratio of the

number of units of horizontal distance

to the number of corresponding units

of vertical distance. The term is used in

English for any inclination and is ex-

pressed as a percentage when the slope

is gentle, in which case the term gradient

is also used.

Slope Protection―the protection of a

slope against wave action or erosion.

Sluiceway―see low-level outlet.

Spillway―a structure over or through

which flood flows are discharged. If

the flow is controlled by gates, it is a

controlled spillway; if the elevation of

the spillway crest is the only control, it

is an uncontrolled spillway.

Auxiliary Spillway (Emergency

Spillway) ―a secondary spillway de-

signed to operate only during excep-

tionally large floods.

Fuse-Plug Spillway―an auxiliary or

emergency spillway comprising a low

embankment or a natural saddle de-

signed to be overtopped and eroded

away during a rare and exceptionally

large flood.

Primary Spillway (Principal Spill-

way) ―the principal or first-used spill-

way during flood flows.

Shaft Spillway (Morning Glory

Spillway) ―a vertical or inclined shaft

into which flood water spills and then

is conducted through, under, or

around a dam by means of a conduit

or tunnel. If the upper part of the shaft



is splayed out and terminates in a cir-

cular horizontal weir, it is termed a

“bell mouth” or “morning glory” spill-

way.

Side Channel Spillway―a spillway

whose crest is roughly parallel to the

channel immediately downstream of

the spillway.

Siphon Spillway―a spillway with one

or more siphons built at crest level.

This type of spillway is sometimes

used for providing automatic surface-

level regulation within narrow limits or

when considerable discharge capacity

is necessary within a short period.

Spillway Channel (Spillway Tun-

nel) ―a channel or tunnel conveying

water from the spillway to the river

downstream.

Stilling Basin―a basin constructed to

dissipate the energy of fast-flowing

water, e.g., from a spillway or bottom

outlet, and to protect the riverbed

from erosion.

Stop logs―large logs or timber or

steel beams placed on top of each

other with their ends held in guides on

each side of a channel or conduit

providing a cheaper or easily handled

temporary closure than a bulkhead

gate.

Storage―the retention of water or de-

lay of runoff either by planned opera-

tion, as in a reservoir, or by temporary

filling of overflow areas, as in the pro-

gression of a flood crest through a nat-

ural stream channel.

Tailrace―the tunnel, channel or con-

duit that conveys the discharge from

the turbine to the river, hence the

terms tailrace tunnel and tailrace canal.

Tail water Level―the level of water

in the tailrace at the nearest free sur-

face to the turbine or in the discharge

channel immediately downstream of

the dam.

Toe of Dam―the junction of the

downstream face of a dam with the

ground surface, referred to as the down-

stream toe. For an embankment dam the

junction of upstream face with ground

surface is called the upstream toe.

Top of Dam―the elevation of the up-

permost surface of a dam, usually a

road or walkway, excluding any para-

pet wall, railings, etc.



Top Thickness (Top Width) ―the

thickness or width of a dam at the level

of the top of the dam. In general,

“thickness” is used for gravity and arch

dams, “width” for other dams.

Transition Zone (Semi-pervious

Zone) ―a part of the cross-section of

a zoned embankment dam comprising

material of intermediate size between

that of an impervious zone and that of

a permeable zone.

Trash rack―a screen located at an in-

take to prevent the ingress of debris.

Tunnel―a long underground excava-

tion usually having a uniform cross-

section. Types of tunnel include: head-

race tunnel, pressure tunnel, collecting

tunnel, diversion tunnel, power tunnel,

tailrace tunnel, navigation tunnel, ac-

cess tunnel, scour tunnel, draw-off

tunnel, and spillway tunnel.

Under seepage―the interstitial

movement of water through a founda-

tion.

Uplift―the upward pressure in the

pores of a material (interstitial pres-

sure) or on the base of a structure.

Upstream Blanket―see blanket.

Valve―a device fitted to a pipeline or

orifice in which the closure member is

either rotated or moved transversely or

longitudinally in the waterway to con-

trol or stop the flow.

Water stop―a strip of metal, rubber

or other material used to prevent leak-

age through joints between adjacent

sections of concrete.

Weir―(a) a low dam or wall built

across a stream to raise the upstream

water level, called fixed-crest weir

when uncontrolled. (b) A structure

built across a stream or channel for

measuring flow, sometimes called a

measuring weir or gauging weir. Types

of weir include broad-crested weir,

sharp-crested weir, drowned weir, and

submerged weir.


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Central Dam Safety Organisation

Central Water Commission

Vision

To remain as a premier organisation with best technical and managerial ex-pertise for providing advisory services on matters relating to dam safety.

Mission

To provide expert services to State Dam Safety Organisations, dam owners, dam operating agencies and others concerned for ensuring safe functioning of dams with a view to protect human life, property and the environment.

Values

Integrity: Act with integrity and honesty in all our actions and practices.

Commitment: Ensure good working conditions for employees and encourage professional excellence.

Transparency: Ensure clear, accurate and complete information in communi-cations with stakeholders and take all decisions openly based on reliable in-formation.

Quality of service: Provide state-of-the-art technical and managerial services within agreed time frame.

Striving towards excellence: Promote continual improvement as an integral part of our working and strive towards excellence in all our endeavours.

Quality Policy

We provide technical and managerial assistance to dam owners and State Dam Safety Organizations for proper surveillance, inspection, operation and maintenance of all dams and appurtenant works in India to ensure safe func-tioning of dams and protecting human life, property and the environment.

We develop and nurture competent manpower and equip ourselves with state of the art technical infrastructure to provide expert services to all stakehold-ers.

We continually improve our systems, processes and services to ensure satis-faction of our customers.