4. SPATIAL DATABASE CREATION AND ANALYSIS

51

4. SPATIAL DATABASE CREATION AND ANALYSIS

4.1 OVER VIEW

For creation of spatial digital database both spatial and aspatial data is

required. Spatial data consist of base drainage transport, land use/land

cover soil geomorphology and physiographic maps. The aspatial data

consist of socio-economic and collateral data. For developmental

planning, it is necessary to prepare thematic maps. Thematic maps are

very much useful for management of natural resources. These maps are

prepared using satellite imageries and toposheets data using visual

interpretation and digital interpretation techniques.

4.1.1 Acquisition and Processing of Topomaps and Satellite Data

Acquisition and processing of raw data for preparation of thematic maps

involves the following steps.

1. Acquisition of satellite image( IRS-P6 LISS-IV MX 5.8 X 5.8 mt

resolution) data of the year 2007 from National Remote Sensing

Centre (NRSC), Balanagar, Hyderabad and toposheets on 1:25,000

scale from (SOI) Survey of India, Hyderabad.

2. Georeferencing of Survey of India toposheets based on latitude and

longitude values given in the topomaps.

52

3. Subsetting and mosaicing done for the georeferenced toposheets to

form a continuous terrain and preparation of digital mosaic depicting

the entire study area.

4. Georeferencing of satellite data by taking the toposheet as reference,

extracting the Ground Control Points (GCPs) from SOI toposheets and

placing to the satellite imagery to bring it to real world.

5. Digital image enhancement and application of correction models for

making the digital data free from errors and distortions both

radiometry and geometry of the satellite data.

6. Preparation of thematic maps using visual interpretation technique

and digital image interpretation technique.

4.1.2 Visual Image Interpretation

A spatial image carries detailed information of all the features over the

surface of the earth at data acquisition time. Examine of the images is

systematically done by the image interpreter. Number of complexity

levels occurs during the interpretation of the spatial images. The study of

spatial images and Arial photographs includes various characteristics

displayed on an image viz., tone, pattern, texture, shape ,size, and

association etc , these all characteristics helps in interpretation of

different features on Arial photographs and satellite imagery during the

classification of features. In this present study, for the fused pictoral

data classification, key is prepared for a preliminary image, which is

53

used during image interpretation process. Image interpretation key is

used for the extraction and transferring of the thematic features from the

satellite imagery. The doubtful areas are listed during preliminary image

interpretation before ground confirmation. After field verification based

on the information collected, modifications and corrections of doubtful

areas are carried out.

4.1.3 Generation of Spatial Database

Based on physical characteristics in the study area, derivation methods

of maps, (IMSD Technical Guidelines, NRSA, 1995) their sources,

environmental sensitivity and suitability of the following maps are

prepared. The types of data relevant to digital database are classified

based on origin of acquisition and creation. To prepare the digital

baseline database, three various types of data are defined.

a) Topographic Data: Maps prepared from (SOI) Survey Of India

toposheets (1:25,000) scale.

b) Collateral Data: Detailed socio-economic data, cadastral maps with

survey points, developmental work detail and other miscellaneous

data.

c) Thematic Data: Maps prepared by using IRS-P6 LISS-IV-MX high

resolution satellite data on 1: 10,000 scale.

54

Topographic data Collateral data Thematic data

Base map Detailed socio-economic data Land use/Land

cover map

Administrative boundaries Cadastral survey points Geomorphology

map

Transport map Developmental work details Soil map

Drainage map GPS Survey points

Watershed map Other miscellaneous data

Slop map

Physiography map

Table 4.1 shows the generation of spatial database

4.2 SPATIAL DATA GENERATED FROM TOPOSHEETS

The various spatial databases generated from survey of India (SOI)

toposheets relevant for this study are:

Base map.

Drainage network map.

Transport network map.

Watershed map.

Physiography map.

Mandal reference map with village boundaries.

55

Fig 4.1 Showing the toposheet map of the study area (Source: Survey of India Toposheets)

56

4.2.1 Base Map Generation

Map is a representation of various features present on the earth’s surface

drawn to scale. A topographical map is a representation of physical

features of a given area. A base map is a skeleton structure of an area. A

base map is composed of various different features like administrative

boundaries, settlements, road network, water bodies, railway tracks,

canal, and forest etc., which are extracted from the topsheet. The base

map therefore drawn is scanned and digitized using ARCGIS software to

get digital output.

A map, representing the outline structure of the study area, is

known as a base map. The base map preparation is done by using survey

of India (SOI) toposheets on 1:25,000 scale (66A01NE, 66A01SE and

66A05NW 66A05SW) and with help of the satellite imagery the baseline

information is been updated. The features in the base map consist of

mandal boundary, village boundary, taluk boundary, water bodies, major

canal, major settlements, major/minor roads and other towns.

The study area includes seven revenue villages of Karamchedu

mandal namely Audipuai, Daggubadu, Karamchedu, Kesavarapadu,

Kodavalivaripalem, Kunkalamarru, and Swarna. Nagarjun Sagar

Jawahar Canal and Kommamur Major Canal flows through the study

area. A part of Ramperu River also passes through the study area.

57

Fig 4.2 Base map of the studyarea

Prepared by kavita, Centre for Environment, IST, (Source: Survey of India Toposheets)JNTUH

58

Village Wise Base Maps of Karamchedu Mandal

Fig 4.3 Base map of Audipudi and daggubadu village Prepared by kavita, Centre for Environment, IST, JNTUH (Source: Survey ofIndia Toposheets)

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Fig 4.4 Base map of Karamcheduandkesaravapadu village

Prepared by kavita, Centre for Environment, IST, JNTUH(Source: Survey of India Toposheets)

60

Fig 4.5 Base map of Kodavarivalipalem andKunkalamarru village


61

Fig 4.6 Base map of Swarna village Prepared by kavita, Centre for Environment, IST, JNTUH(Source: Survey of India Toposheets)

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4.2.2 Drainage Network Map

All the rivers, streams and canals present in the toposheets delineated to

prepare a drainage network map. Survey of India toposheets (SOI) are

used to prepare drainage network map. And further it is scanned and

digitized using ARCGIS software to get digital database. All water bodies

present in the toposheet are divided into wet areas and dry areas. Wet

water spread areas are not always same, it changes in every season. After

preparing the drainage network map this map is updated using high

resolution satellite imagery to know the newly constructed tanks.

Nagarjun Sagar Jawahar Canal and Kommamur major canal is present

in the study area. A part of Ramperu River also passes through the study

area. The drainage network pattern is dendritic type.

4.2.3 Transport Network Map

In a developing country transport network map plays a vital role for

overall development. For social, economic and educational development,

roads and rail accessibility is very much essential of a region. In the

study area, four classes of transport network namely, the metalled roads,

cart track and pack track area extracted from the survey of India

topographical maps on 1:25,000 scale. The transport network map is

updated with help of latest satellite data to get the information about the

newly constructed roads. All roads are connecting to the major

settlements and hamelets in the study area.

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Fig 4.7 Drainage map of the studyarea


64

Fig 4.8 Drainage map of Audipudi and daggubadu village Prepared by kavita, Centre for Environment, IST, JNTUH(Source: Survey of India Toposheets)

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Fig 4.9 Drainage map of Karamchedu and kesaravapaduvillage


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Fig 4.10 Drainage map of Kodavarivalipalem andKunkalamarru village


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Fig 4.11 Drainage map of Swarnavillage


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Fig 4.12 Transport map of the studyarea


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Fig 4.13 Transport map of Audipudi and daggubadu village Prepared by kavita, Centre for Environment, IST, JNTUH(Source: Survey of India Toposheets)

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Fig 4.14 Transport map of Karamchedu andkesaravapadu village


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Fig 4.15 Transport map of Kodavarivalipalem andKunkalamarru village


72

Fig 4.16 Transport map of Swarna village Prepared by kavita, Centre for Environment, IST, JNTUH(Source: Survey of India Toposheets)

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4.2.4 Watershed Map

Watersheds are the optimal hydrologic units for planning and

implementation of various development programs. Watershed is defined

as a “Natural Hydrologic entity that covers a specific area expanse of land

surface, from which the rainfall runoff flows to a defined drain, channel,

stream or river at any particular point.” From this generalized definition

it emerges that the size of a watershed is governed by the size of the

stream or river in question or the point of interception of the water

course like a dam, barrage, etc. Obviously, no political or administrative

boundaries govern a watershed. The size of the watershed could be some

lakhs of hectares or if a small stream is chosen, the same could be of a

few hundred hectares. To avoid this ambiguity and to suggest a stage

where land development could be of viable size a hierarchical approach

was suggested by the Ministry of Agriculture (MOA), Govt. of India, in

1990. According to Central Water and Power Commission (CWPC), the

country was distinctly delineated into 6 Water Resources Regions (WRR).

Region 1 Rivers falling into Arabian Sea,

excluding Indus system.

Region 2 The Indus basin in India.

Region 3 Rivers falling into the Bay of

Bengal, other than the Ganga and

the Brahmaputra systems

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Region 4 The Ganga system.

Region 5 The Brahmaputra system.

Region 6 Rajasthan.

Table 4.2 Water resources regions

Number of Hydrologic Units at Different Stages of Delineation of our

Country and watershed codification:

Regions Hydrologic units Watershed codification

Water Resources Regions 6 5.0 la sq.km (+)

Basins 35 0.50 la sq.km (+)

Catchments 112+ 0.05 la sq.km (+)

Sub-catchments 500+ 0.005 la sq.km (+)

Watersheds 3237+ A few hectares of land

Table 4.3 watersheds codifications

An alfa-numerical system of codification has been suggested by the MOA

under this system:

Water resources regions are assigned

numbers

1,2,3,4,5 & 6

Basins A, B, C……..

Catchments 1, 2, 3……….

Sub-catchments A, B, C……..

Watersheds 1, 2, 3……….

Sub Watersheds a, b, c………

75

Mini Watersheds 1, 2, 3………

Micro Watersheds a, b, c……..

Table 4.4 watershed alfa numerical codifications

Thus, watersheds will have the codes like 1A1A1a1a...4C4D1c1c...

Watershed map scale

For extraction and identification of various different levels of hirachy

following map scale are proposed:

Source : SOI Toposheet, Ariel photograph and satellite imagery

Region : 1:1 Million

Basin : 1:1 Million

Catchment : 1: 250,000

Sub-catchment : 1: 50,000

Watershed : 1: 50,000

Sub-watershed : 1:50,000

Mini Watershed : 1:25,000

To prepare a watershed map, Survey of India toposheet (SOI) on

1:25,000 scale is used. SOI toposheet provides information about the

exact location of drainage network, and further it is updated with

satellite data to know newly formed stream or newly constructed tanks

etc. Watershed coding is shown in the fig 4.17 of the study area

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Fig 4.17 watershed map of the study area Prepared by kavita, Centre for Environment, IST, JNTUH (Source: Survey of IndiaToposheets)

77

4.2.5 Physiography Map

Physiography map is to apprehend distribution and disposition of the

barriers of winds. This map is prepared using contours extracted from

SOI toposheets. In the study area, only one category is demarcated in the

map that is plains.

In the study area entire area is covered with plains, which

indicates very gentle slope terrain.

4.2.6 Mandal Reference Map With Village Boundaries

Mandal reference map is generated from Survey of India toposheet (SOI)

on 1:25,000 scale. There are seven revenue villages in the Karamchedu

mandal namely Audipudi, Daggubadu, Karamchedu, Kesavarapadu,

Kodavalivaripalem, Kunkalamarru and Swarna

The mandal Reference map of study area is shown in fig. 4.19

78

Fig 4.18 physiography map of the study area Prepared by kavita, Centre for Environment, IST, JNTUH(Source: Survey of India Toposheets)

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Fig 4.19 Showing mandal reference map of the study area Prepared by kavita, Centre for Environment, IST, JNTUHSource: Survey of India Toposheets)

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4.3 SPATIAL DATA GENERATED FROM SATELLITE DATA AND

OTHER DATASETS

Satellite data gives exact information about the features on the surface of

the earth. The spatial information on the earth surface changes time to

time. Spatial information depends on the resolution of the sensor. There

are four types of resolution, i.e. spatial resolution, temporal resolution,

radiometric resolution and spectral resolution. Spatial resolution

depends on the sensor of the satellite the finer is the resolution the more

detailed information is obtained. In the study area RESOURCESAT IRS –

P6 LISS-IV MX (5.8x5.8 mt) high resolution satellite data is used to get

more detailed information.

Fig 4.20 Showing satellite image of the studyarea (Source: National Remote Sensing Centre- NRSC)

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4.3.1 Generation of thematic layers

Land use /Land cover map. Soil map. Geomorphology.

4.3.2 Land Use/Land Cover Map

Land use pattern changes time to time everyday. Information on the use

of land resources is indispensable for the proper management, planning

and use of those resources. Land resources are very limited on the earth

surface. To tackle the uncontrolled growth related problems, knowledge

about the land use and land cover changes is necessary. For updating

land use/land cover maps time to time, a systematic framework is

required.

Remote sensing is rapidly rising technology, which helps in

collection and mapping land use/land cover data above huge area. As

remote sensing data is obtained in digital format, it is more amenable for

digital image processing. Land use map helps in study of environmental

problems and processes and it gives the information about the existing

land use pattern and helps to improve maintain the current level. Thus,

land use map is prepared to give ideas to planner of land, use pattern

and changes occurring everyday on the earth’s surface.

4.3.2.1 Objective

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The main objectives of this new land use / land cover classification

system are:

To prepare a detailed framework and cover five levels of

classifications of land use/land cover as possible.

To prepare land use/land cover map with IRS –P6 LISS-IVMX (5.8

X 5.8 mt), high resolution satellite data and extract various land

use/land cover categories with the help of digital image processing.

To develop village level land use/land cover classification for micro-

level planning.

To prepare 1:10,000 large scale map.

4.3.3 Technical Steps of Digital Image Classification

Digital Image Processing (DIP) Techniques can be divided broadly into

4 groups. They are:

Image Rectification and Restoration.

Image Enhancement.

Image Interpretation.

Data Merging.

4.3.3.1 Image Rectification and Restoration

Before digital image processing, pre-processing is done for the raw

satellite data. Image rectification and restoration is done for raw satellite

data. Raw satellite obtained from the satellite sensor is either degraded

83

or distorted. The raw satellite data is geometrically corrected to remove

the distortion of the image, and the image is radiomrtrically corrected to

remove the noise effect from the satellite data. The nature of the satellite

data depends on the sensor of the satellite.

4.3.3.2 Image Enhancement

The raw satellite images received from the satellite sensors are not

interpretable mainly due to unfavorable weather condition and requires

image enhancements. Image enhancement is the procedure carried out

to clear and enhance the basic quality of the image to be interpreted. It

includes spatial enhancement, radiometric enhancement and spectral

enhancements. This technique helps to interpret the maximum

information from the raw satellite image. These enhanced images can

further be displayed on the monitor and can be recorded in the form of

hard copy in both color and black and white.

4.3.3.3 Image Interpretation

There are two types of interpretations, visual interpretation and digital

interpretation. Visual Interpretation is based on principal image

identification. It is based on object recognition and characteristics of the

image. The image characteristics are tone, shape, pattern, size, shadow,

association and texture. Digital image interpretation deals with thematic

information extraction in digital classification. In digital interpretation,

84

computer interpretation is subjective to two types of classification,

supervised and unsupervised.

(a) Supervised classification: The identity and location of pixels are known

that is priory knowledge of the training pixel is known by the interpreter

based on ground truth. Spectral characteristics of the training pixels are

used to train the classification pixels are assigned to a particular class, to

which it has highest likelihood being a member. Representative training

sites are selected for the process of signature extension. Statistics is

extracted for each training site. Selection of appropriate classification

algorithm classifying the image into required number of classes. Statistical

evolution is for the classification accuracy.

(b) Unsupervised classification: In unsupervised classification, the

interpreter does not have the knowledge of the classes or categories in this

classification. The role of interpreter is minimum. Classification based on

concept of natural clustering of the pixel. There are two methods, which

are most commonly used in unsupervised classification that is chain

method and isodata method.

4.3.3.4 Data merging

Data merging is the procedure carried out to merge two different

geographically referenced images of the same area in order to get high

resolution data.

85

4.3.4 Methodology for land use/land cover mapping

For interpretation and analysis of land use/land cover mapping, baseline

data and ground data is required. Basic data includes satellite data from

NRSC, toposheets data from SOI, local knowledge, area map, reports and

literature about the study area. Ground data is important to get the

accurate information. Flowchart 4.1 showing the methodology adopted

for land use/land cover mapping.

Flowchart 4.1: Flowchart showing the Methodology adopted forLand Use/Land Cover mapping

Final land use/land cover mapwith symbols and color

Basic data Data source

IRS –P6-LISS-IV-MX Preparationof basemap

Interpretation and mapping ofland use /land cover categories

Ground verification of doubtful areas andmodification of thematic details

Area estimation of eachLand use/Land cover

classes

Development ofinterpretation key based

on imagecharacteristics.

Validation andfinal

interpretationkey

Secondary data

86

Table: 4.5 Data Model for Land use/Land cover on 1:10,000 Scale

Level 1 Level 2 Level 3 Level 4 Level 5I Built-up 11 Urban/ Built-up

Land111 Residential

1111 High Density1112 Medium Density1113 Low Density

11111 Single Unit Highdensities

11112 Multiple dwellingLow rises

11113 Multiple dwellinghigh rises

112 Industrial1121 Light industrial1122 Heavy industrial1123 Power generation

113 Commercial

1131 Central Business centers1132 Commercial strips1133 Commercial establishmentsfor

goods and services1134 Isolated commercial office

buildings1135 Shopping centers1136 Resorts, Hotels &related

Facilities

114 Services

1141 Educational institutions1142 Health institutions1143 Correctional institutions1144 Government centers1145 Military installations1146 Other institutions

87

115 Recreational

1151 Parks1152 Play grounds1153 Stadiums1154 Race course1155 Golf course1156 Swimming pools1157 Cultural centers andTheatres1158 Other recreational places

116.Transportation

Communication andUtilities

1161 Major road ways

1162 Railway facilities

1163 Bus stands1164 Airports1165 Power facilities1166 Telephone1167 Port facilities1168 Water & sewage treatment1169 Others

11611 NH11612 SH11613 District Roads11614 Other Roads

11621 Broad gauge11622 Meter gauge

88

117 Open spacesor vacantland

1171 Undeveloped land withinurban area1172 Inactive land1173 Open areas

118 Others

12 Village / Rural

2.Agriculture 21 Crop land 211 Kharif212 Rabi213 Kharif +Rabi214 SummerCrop

22 Fallow221 CurrentFallow222 Permanent

Fallow23 Plantations

231 AgriculturalPlantations

2311 Tea2312 Coffee2313 Rubber

232 HorticulturalPlantations

2321 Coconut2322 Arecantnut2323 Citrus fruits2324 Orchards2325 Nurseries2326 Floury culture

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233 Agro-HorticulturalPlantations

2331 Seed forms2332 Others

24 Aquaculture/Pisciculture

3. Forest 31 Evergreen/ Semievergreen

32 Deciduous(Moist/Dry)

33 Forest Plantations

34 Scrub Forest

35 Forest Blank

36 Mangroves

37 Shifting cultivation

311 Dense/Closed312 Open/Degraded321 Dense/Closed322 Open331 Teak Forest332 BambinoForest333 Eucalyptus334 Casuarinas

361 Dense362 Open/

Degraded

4 Wastelands 41 Salt Affected Land

42 Gullied/ RavenousLand

43 Scrub land431 DenseScrubs432 Open Scrubs

90

44 Sandy area

45 Mining/ Industrialwaste/ Ash

441 Coastal Sand442 ReverineSand

451 Mine Dumps452 IndustrialDumps453 Ash Ponds

5 Waterbodies

51 Rivers/ Stream

52 Canals

53 Reservoirs/ Tanks

54 Lakes/ Ponds55 Cooling pond/

Coolingreservoir

56 Bay

511 Perennial512 Dry(Ephimeral)513 River Island514 River bed

Cultivation

521 Lined Canal522 Unlined

531 Perennial532 Dry

5311 Multi purpose reservoirs5312 Balancing reservoirs

541 Perennial542 Dry

561 Back waters562 Estuary/Kayal563 Creek564 Lagoon

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6 Wetlands 61 Inland Natural

62 Inland Manmade

63 Coastal Natural

64 Coastal Manmade

7 Natural /Semi-NaturalGrass landand Grazingland

71 Alpine/Sub-Alpine

72 Temperate/ Sub-

Tropical

73 Tropical/Desertic

74 Man Made

Grasslands/ Fodder

Crop

8 Snowcovered

92

4.3.5 Land Use/Land Cover Description of Study Area

The Land use/Land cover categories such as built-up land, agriculture,

water body, waste lands, canals, rivers, roads, and tanks have been

identified and mapped from the study area. Major part of the study area

is covered with double crop 50% and under built-up land 6%. The

agricultural area could be clearly delineated as three categories, single

crop, double crop and fallow land. Though, double crop has been

observed at various parts of the study area, single crop is observed only

at a few places of the study area. Approximately 4% of the area is covered

with land without scrub and rest of 40% of the area is covered with water

bodies.

Percentage wise distribution and area in sq.km of the study area.

Canal1%

wet tank1%

Double crop37%

harvested crop1%

Residential area2%

River with water1%

Road2%

Single crop54%

Pie Chart: 4.1 chart showing percentage distribution of Land use/ Land cover inthe study area

93

Fig 4.21 Land use /land cover map of the study area Prepared by kavita, Centre for Environment, IST, JNTUH(Source: IRS P6 LISS-IV MX Satellite image from NRSC)

94

Class Area (Km2)

BUND 0.34CANAL 1.316CURRENT FALLOW LAND 0.55DOUBLE CROP 56.97DRIED TANK 0.371FALLOW LAND 0.011HARVESTED CROP 1.295KOMMAMUR CANAL 0.599LAND WITHOUT SCRUB 0.292NAGARJUNASAGAR JAWAHAR CANAL 0.164POND 0.033RESIDENTIAL AREA 3.74RIVER WITH WATER 0.917RIVER WITHOUT WATER 0.527ROAD 2.53SINGLE CROP 83.93WET TANK 0.787

Table 4.6 Land Use/Land Cover Distribution in the Study Area

4.3.5.1 Crops Cultivated

Paddy, maize, bengal gram, black gram, chilli, cotton, tobacco and jute have

been identified in the study area. Lift irrigation facilities are available in the study

area.

Table 4.7 Area under principal crop cultivation

Crop Name Kharif Rabi Total

IrrigatedUnirrig-ated

Irrigated Unirrigated Irrigated

Unirrigated

Paddy 5993 0 7110 0 13103 0Maize 0 0 0 60 0 60Black gram 0 352 0 1439 0 1691Chillies 0 239 0 460 0 699Cotton 0 180 0 0 0 150Jute 0 20 0 0 0 20Tobacco 0 0 0 105 0 105Bengal gram 0 0 0 2271 0 2271

95

Table 4.8 Village wise Land use / Land cover area in Km2

VillageName Bund Canal

CurrentFallowLand

DoubleCrop

DriedTank

FallowLand

Harv-stedCrop

Komm-amurCanal

LandWithoutScrub

NagarjunSagarJawaharCanal Pond

Reside-ntialArea

RiverWithWater

River

withoutWater Road

Sin-gleCrop

WetTank

Audipudi 0.172 5.008 0.002 0.00004 0.514 0.095 0.033 0.188 12.044 0.17

Daggubadu 2.225 0.172 0.11 0.00019 0.0976 0.577 0.072 0.198 0.193 12.453 0.102

Karamchedu 0.345 0.428 19.942 0.0077 0.186 0.194 0.0045 1.046 0.686 0.196 0.33 13.061 0.223

Kesavarapadu 0.21 0.025 0.023 0.193 0.0287 0.068 2.827 0.1

Kodavalivaripalem 0.035 0.055 9.707 0.094 1.295 0.076 0.023 0.043 0.254 0.06 0.024 0.21 9.445 0.085

Kunkalamaru 0.179 5.379 0.144 0.022 0.468 14.818 0.04

Swarna 0.496 14.451 0.068 0.191 0.074 0.005 0.691 0.044 1.545 19.218 0.063

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Village Wise Land Use/Land Cover Maps Of Karamchedu ,Mandal

Fig 4.22 Land use/Land cover map of Audipudiand

daggubadu village

Prepared by kavita, Centre for Environment, IST, JNTUH(Source: IRS P6 LISS-IV MX Satellite image from NRSC)

97

Fig 4.23 Land Use/Land cover map of Karamchedu andkesaravapadu village


98

Fig 4.24 Land use/Land cover map of Kodavarivalipalem andKunkalamarru village


99

Fig 4.25 Land use / land cover map ofSwarna village


100

4.4 SOIL MAP

4.4.1 Methodology

Soil map is prepared with the help of Survey of India toposheets on

1:25,000 scale and IRS P6 LISS-IV MX (5.8 x5.8 mt) satellite imagery

from NRSC. Topographic data is taken and it is superimposed on the

satellite data. Further image characteristics namely texture, tone,

pattern, shape and association are prepared in order to compare with the

soil distribution. Strip wise samples were haphazardly selected for

further field verification. Field visits are carried out to know the soil

profile characteristics and correlate the interpretation units with the

given study area. After the field verification and observations carried out

in the field, soil boundaries are drawn throughout the preliminary visual

interpretation and legends were prepared showing the soil series.

Afterward, the soil boundaries were shifted to the base map. The soil

map is shown in fig 4.26.

101

Fig 4.26 Soil map of the studyarea

Prepared by kavita, Centre for Environment, IST, JNTUHSource: National Bureau of Soil Survey (NBSS)Nagpur)

102

Soil Code Description Soil Taxonomy

238

Deep, well drained,

gravelly clay soils with

surface crusting and

low AWC; on gently

sloping plains,

moderately eroded and

associated with very

deep well drained

clayey soils.

Fine, mixed, Rhodic

Paleustalfs.

241

Deep, well drained, red

coastal clayey soils

with high awc, on very

gently sloping plains,

slightly eroded;

associated with very

deep, well drained, red

coastal clayey soils.

Fine, Mixed, Typic

Ustropepts,--Fine,

Mixed,Typic

Haplustalfs

246 Moderately deep,

moderately well

drained, black

cracking clay,

Fine, Montmorillonitic

(calcareous), Vertic

Usropepts)-- Fine,

Mixed, Typic

103

calcareous soils with

high awc, on very

gently sloping plains,

slightly eroded;

associated with deep,

well drained, black

clayey soils.

Ustropepts

Table 4.9 Distribution of soil type in the study area

4.5 GEOMORPHOLOGY

4.5.1 General

The Geomorphological map is prepared by demarcating the geomorphic

units and land forms. All available geomorphic units and forms are listed

after interpreting the study area. All the listed geomorphic units and

landform details are grouped/classified as per the origin like fluvial,

alluvial, structural, etc. The geological details like lithology/rock types

and structural details are also delineated using available

geological/geomorphological maps of the area. Then these geological

details are incorporated on geomorphological map for identifying the

groundwater potential associated with each geomorphology unit. For

instance pediment/Pedi plain without fractures/joints and lineaments

normally has moderate to poor groundwater prospect where as the same

geomorphic unit with a network of fractures/joints indicates good

104

groundwater prospects. Similarly, a Pedi plain area of

crystalline/metamorphic rock is marked by poor to moderate

groundwater prospect wherein the same unit in sandstone or

limestone/sedimentary rock can have a good to moderate prospect. The

geomorphic units are delineated based on the image characteristics like

tone, texture, shape, color, associations, background, etc. The following

geomorphic units are delineated in study area.

Geomorphicunit/ land form

Description Influence on ground waterregime

Moderatelyweatheredpediplain.PPM

Gently undulating plain of large arealextent often dotted with inselbergsformed by the coalescence of severalpediments. Based on the depth ofweathering, weathered pediplains areclassified into 3 categories: (1) shallow(0-10m), (2) Moderate (10-20m), (3) Deep(>20m). Nearly half of the study area i.e.41.1% (2644.16 Km2) is occupied by thisclass. PPM is well distributed in theentire study area and is observed inareas along Musi river and in areassurrounding the tanks.

Pediplain occupied by semi-consolidatedsediments form good aquifers dependingon their composition. In hard rocks,they form very good recharge andstorage zones depending upon thethickness of weathering andaccumulated material and itscomposition. Faults/fractures zonespassing through pediplains act asconduits for movement and occurrenceof groundwater.

ShallowweatheredpediplainPPS

Gently undulating plain of large arealextent often dotted with inselbergsformed by coalescence of severalpedimets. Based on the depth ofweathering, weathered pediplains areclassified into 3 categories: (1) shallow(0-10m), (2) Moderate (10-20m), (3) Deep(>20m). This is the second major classobserved in the study area with a totalarea of 2212.18Km2 (34.42%). Itoccupies mostly the western andnortheastern parts of the study area.

Pediplain occupied by semi-consolidatedsediments form good aquifers dependingon their composition. In hard rocks,they form very good recharge andstorage zones depending upon thethickness of weathering andaccumulated material and itscomposition. Faults/fractures zonespassing through pediplains act asconduits for movement and occurrenceof groundwater.

Valley FillVF

Valleys of different shapes and sizesoccupied by valley fill material (partlydetrital and partly weathered material).They are classified into 3 categories – 1)Shallow (0-10 m), 2) Moderate (10-20m), 3) Deep (more than 20 m). Valley fillin the present study area occupy10.89Km2 in the southeastern part.

Form moderately productive shallowaquifers, subject to thickness of valleyfill material, its composition andrecharge conditions.

Table 4.10 Geomorphic units in the study area

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Fig 4.27 Geomorphology map of thestudy area


Documents

4. SPATIAL DATABASE CREATION AND ANALYSIS