Powerpoint long term dredging plan using W.I.T

Dhaka WASA - VEI project

1 1

Preparation

2.3 Long term Urban Dredging Plan (WIT)

• Dredging strategy

• Sediment growth figures

• Clustering drainage units to dredging units

• Needed budgets

5

operational excellence - sustainable services - bilateral cooperation

5

Take-home message(s):

Long term Urban Dredging plans gives insights in needed budgets!

How many years is long term?

What is the difference between drainage unit and dredging unit?

5


5

Learning Objectives of the Topic/Session:

At the end of the session the participants will be able to:

1. Explain the importance of Long term Urban Dredging Plans (LUDP)

2. Identify needed figures for making LUDP’s

3. Explain your dredging strategy

4. Relation between data collection and long term planning

5


5

LUDP gives answers to

1. Where to dredge in order to meet your design and hydraulic requirements

2. When to dredge in order to meet your design and hydraulic requirements

3. Costs and thus needed budgets when dredging at a certain place is required

Floods are caused when your drainage system does not fulfill your design

and hydraulic requirements

5


5

WIT: Data information

Feasibility plan

Dredging plan

Do: dredging!

Framework assessment: from required

hydraulic dimensions to dredging

strategy

LUDP

Side selection

5


5

Generating LUDP’s you need:

1. WIT data information: what is in there?

Hydrographic survey and sampling (2 out of 7 catchments are known)

2. Framework assessment = Dredging strategy

3. Operational “Do” methods & Unit prices (unit prices x amounts = costs)

4. Sediment growth figures

5. Defined dredging units (side selection)

6. LUDP module WIT

5


5

Dredging strategy (important!)

• Dredging strategy = Dhaka WASA policy!

• Highly related with hydraulic capacity of your drainage system!

• Budgets and dredging strategies are strongly related!

• Dredging strategy = intervention depth and corresponding

dredging profile (with or without base layer)

5


5

Dredging strategy: required hydraulic dimensions

intervention depths

Intervention depth

Question: how much you should remove to fulfill your requirements above?

What does this picture mean?

Answer: nothing! Actual sediment is still below intervention depth!

Which year do you have to intervene when requirements do not fullfill anymore (when

does sediment reach intervention depth)?

WIT calculates year and corresponding amounts and costs!

5


5

Dredging strategy Kalyanpur: redefined canal contruction to dredging profile

(in this case: intervention = dredging profile)

Define your dredging strategy in WIT

754 + 112 = 866 m3

Question 1: Dredging amount in

this drainage unit?

Question 2: dredging strategy in

Segunbagicha box culvert?

WIT: all & only sediment

(Or 50 %)

5


5

Operational “Do” methods and unit prices (1)

• Define dredging-, transport and disposal methods and link to

drainage units in WIT

• WIT visualize defined methods on maps,

Question: What characteristics has the drainage unit Segunbagicha Box culvert if it will be dredged?

5


5

• Over-estimated unit prices used in WIT

WIT calculation: 49.283 m3 sediment in Segunbagicha Box Culvert

Dredging costs Segunbagicha: amount of sediment x unit prices

Operational “Do” methods and unit prices (2)

5


5

Sediment growth figures

1. Only Agargeon figures are known based on construction year and survey

0,25 meter/year

2. Currently, sediment growth survey: Kallyanpur Canals & Segunbagicha drains

Cross section ID Location Previous done

measured by

Date of previous

measurement

Survey

round 1

Survey

round 2

Survey

round 3

Survey

round 4

Kallyanpur_Main_D-39 Main Canal Globe survey January 2014 Week 45

2014

Week 06

2015

Week 19

2015

Week 32

2015

Kallyanpur_Main_D-13 Main Canal Globe survey January 2014 Week 45

2014

Week 06

2015

Week 19

2015

Week 32

2015

Kallyanpur_Main_UP-13 Main Canal Globe survey January 2014 Week 45

2014

Week 06

2015

Week 19

2015

Week 32

2015

Kallyanpur_Side3_25 Side Canal

3

BIDCON survey July 2014 Week 45

2014

Week 06

2015

Week 19

2015

Week 32

2015


4


2014

Week 06

2015

Week 19

2015

Week 32

2015


6


2014

Week 06

2015

Week 19

2015

Week 32

2015

Kallyanpur survey schedule

5


5

Defined dredging units

Drainage unit

(specific characteristics: dimensions,

dredging methods, etc.)

Dredging unit

(project)

Catchment Area

Give examples

…….

…….

…….

Segunbagicha

Segunbagicha upstream box culvert

Segunbagicha box culvert

cluster

5


5

LUDP WIT (1)

• Detail information drainage unit

- Dredging strategy

- Amounts of sediment calculations

- Dredging-, transport- and disposal method

• Unit costs

• Compose/cluster dredging units

• Planning dredging units

• Export planning en key parameters

Drainage unit

Dredging unit

Planning

5


5

LUDP WIT (2)


Drainage unit

Dredging unit

Planning

- Required year of dredging? WIT calculates the year of

intervention with sediment growth figures: signaling

function on maps (e.g. 2018)

(not obligatory to use)

- Use WIT dredging calendar: WIT calculates needed

budgets in annual dredging calendar with unit prices,

sediment growth figures and amounts (m3)

- WIT users are able to slide dredging units in annual

calendar to optimize budgets!

5


5

LUDP WIT (3)


- WIT annual dredging calendar

5


5

WIT demonstration!!

Results:

Amounts and needed budgets if Kallyanpur Main Canal, Agargeon,

Segunbagicha Box culvert and Segunbagicha side drains will be dredged in this year!

Or later……. If the WIT LUDP method is used

5


5

Dhaka data in WIT

- GIS data set with drainage network Dhaka WASA

Provided by Dhaka WASA GIS department

- Hydrographic survey

Globe survey: January 2014, Kallyanpur main Canal

BIDCON survey: August 2014, Kallyanpur side Canals

BIDCON survey: September 2014, Segunbagicha side drains

UDDP survey: December 2013, Segunbagicha Box culvert Currently: rest of Kallyanpur catchment (closed drains), Segunbagicha Khal, sediment growth survey

- Dredging strategy

Kallyanpur Main Canal: designed dredging profile, Agargeon and Segunbagicha: only all sediment

- Chemical quality sediment

Laboratory results: Kallyanpur = uncontaminated & Segunbagicha = contaminated

- Defined dredging units

Kallyanpur Main Canal (UDDP project),

Agareon (UDDP project),

Segunbagicha Box culvert (UDDP project),

Segunbagicha side drains (surveyed and direct related with UDDP project)

5


5

Remaining WIT necessaires

- Dhaka WASA employees to be trained

WIT users at O&M

WIT maintenance at GIS department

- Annual dredging budgets coming 10 years (requirement)

- Intervention levels (requirement)

This represents the minimum hydraulic capacity of your drainage system.

Intervention levels might be designed in the Drainage Master Plan (?)

- If available, dimensions of closed drains

To compare with measurements of hydrographic surveys (data validation)

- If available, hydrographic survey data from other catchment areas

5


5

Take-home message(s):

Long term Urban Dredging plans gives insights in needed budgets!

How many years is long term?

What is the difference between drainage unit and dredging unit?

Questions?

Thank you for your attention!

Data & Analytics

Powerpoint long term dredging plan using W.I.T