Modeling the Effects of Land Use Change on Flooding
Report B.Tech
1. SEDIMENTATION ANALYSIS OF
THATIPUDI RESERVOIR USING
REMOTE SENSING & GEOGRAPHIC
INFORMATION SYSTEM
By
Shahera Begum (10331A0149)
P.V.Srivardhan (10331A0142)
G.Rajya Lakshmi (10331A0121)
K.Gana Chaitanya (10331A0123)
B.Jhansi (10331A106)
Under the Guidance of
Mr. A. Vara Prasad M.Tech (RS & GIS)
Assistant Professor
2. Objectives
• To analyze the sedimentation rate of
Thatipudi Reservoir basing on field survey
• To analyze the Land use and Land cover of
study area for a period of 30 years using
remote sensing.
• To analyze the drainage pattern of the study
area using Geographical Information System.
3. Description of Study area
• Thatipudi Reservoir Project was constructed across
Gosthani River.
• Location: Gantyada mandal, Vizianagaram disrict.
• Latitude: North 18.1699 , Longitude: East 83.1975
• Purpose: To irrigate a total ayacut of 15,378acres
(62.23sqkm).
• Head work: Earthen and Gravity: 585m long.
• Full reservoir level: 90.52m
• Gross storage capacity: 94.164MCM.
• Live storage capacity: 88.04MCM.
5. Methodologies
Topographical Satellite Field Work
Contour Toposheet Analysis
Base Map Creation
Selection of Study Area
Procurement of Satellite Images
Re-sampling of Satellite Images
Supervised Classification
Geo Referencing
Data Processing
Actual water spread and volume
estimation
Comparison & Analysis
Classified Image
Sample signature
Recoding
Drainage
DEM
Data collection
Results & Recommendations
6. Data collection
• Data was collected from irrigation department which constitutes of
details related to precipitation, inflow, outflow, capacity of reservoir
for the past 30 years i.e., from 1980-2013.
• Area elevation curve of Thatipudi reservoir is also collected.
• Satellite images from National Remote Sensing Centre (NRSC) and
earth explorer were also taken for land use and land cover analysis.
The dates for which the satellite images were classified are:
From Earth Explorer website-In the year 1973,October, year 1975
December, year 1977 February
From NRSC-In the year 1988, October, year 1990, February
From Bhuvan -In the year 2009, October, year 2011, December
• Water depths at various locations in the reservoir were measured
to compute the amount of sediment upto year 2014.
7. 1.Estimation of volume of sediment based on
field survey conducted on 28th February, 2014
Field survey –
• Depth of water column at various locations were determined
in the reservoir area.
• The average value of depth of water column was taken and
depth of sediment deposited on the reservoir bed was
calculated with respect to bed level.
• Amount of sedimentation was calculated using prismoidal
formula.
8. Water depth of reservoir
Average water column is 52.387 ft
Depth of sediment deposited is given by
Level upto which sediment is deposited - Bed level
= (Reservoir level - Average water column)-Bed level
= (292 - 52.387) - 220
=19.613 ft
9. Sediment calculation
Prismoidal formula is given by:
V=H(A1+A2+√A1*A2) / 3
Where
V=volume of sediment deposited
H=Difference in depth between two successive depth contours
A1=Cross section area within the outer depth under consideration
A2= Cross section area within the inner depth under consideration
The total volume of sediment deposited is 51.84 MMCF
10. Results obtained from field survey:
Volume of sediment obtained yearly basing on
rainfall data
13. 2.By creating 3D-DEM:
• Surface areas from different time periods are obtained based on different images
available.
• Contours are generated based on those areas and Reservoir DEM is created.
• Similarly another DEM is created based on the water level depths obtained from
field survey data.
• In Arc Scene, those two DEMs are overlapped and the sediment volume is
calculated , i.e., the volume under sediment plane.
• The approximate volume of sediment is found to be 63MMCF
14. Result obtained:
Reservoir side view
Reservoir 3D view
Reservoir with sediment plane 1 Reservoir with sediment plane 2
The estimated sediment volume is found to be 63MMCF by 2014.
15. 3.Land use and land cover analysis
Image classification is done to know the land use pattern.
• It is mainly done in 3 steps:
1. Geo-referencing:
The available satellite image is geo-referenced to
an already available reference image like a topo-sheet
2. Subset:
The geo-referenced image is then clipped to the
required watershed area
3. Supervised classification:
The clipped image is then classified on the basis
of supervised classification
• The change in cover for different years is analyzed and the
possible sedimentation causes are determined.
23. Comparizon of percentage area of each class
The table enlisted above for various classes depicting the areal spread clearly shows
that major part of the water shed is vegetation. In the year 1988 and 1990 there
was a sudden decrease in vegetative cover which might be due to deforestation. In
these years area under agricultural increased tremendously.
27. Discussions
• The amount of sedimentation obtained using
theoretical formula was 51.84 MCft where as that
obtained by using Arc GIS was around 63 MCft. If
better survey methods would have been used then the
values might have been more comparable.
• Basing on rainfall data the estimation of sediment
deposited yearly plotted in the form of graph shows a
deviation in the year 1990 which is very high compared
to other years.
• In the year 1990 the vegetation area suddenly reduced
which might be the possible reason for increase in
sediment deposition.
