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GIS based Rainfall Runoff modelling

IWRA World Water Congress 2008 Montpellier France
1. Water availability, use and management
GIS BASED RAINFALL RUNOFF MODELLING Francis Rex V. J II Year M.E Hydrology & Water Resources Engg. rex_pec@yahoo.com

Keyword(s): Key words: Geographical Information System, Soil Conservation Services
Article: Poster:

AbstractABSTRACT Hydrological modeling is of prime importance for hydrologists in planning, design and operation of water resources related structures. In this study a Rainfall Runoff model is being developed in a GIS environment. Vaippar basin is chosen as the study area for this particular study. GIS is used as a tool to derive the parameters necessary to develop the model. Various database such as base map preparation, land use, soil type, drainage map and contour map were prepared. The parameter derived from GIS is used in an appropriate method to develop the Rainfall Runoff Model. Using overlay analysis of land use and soil type map the Curve Number is derived using area weighting method. Runoff can be calculated using SCS method. A digital Elevation Model is created in order to get the surface pattern of the basin. DEM is created using contour digitizing. The flow direction and flow accumulation were also got from the DEM created. Various topographic attributes such as slope, catchment area and aspect were also derived from the created DEM. The parameters obtained were used to calculate the time of concentration of each cell. The cells having same time of concentration were joined to form the isochrones. The area between two isochrones were calculated which is used to derive the Time-Area curve of the study area. The slope of Time-Area is calculated and that is the ordinate of Unit Hydrograph (UH). From the unit hydrograph and the runoff derived the storm hydrograph can be derived.
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