Authors : W. P. S. Dilanganee; I. A. K. S. Illeperuma

Volume/Issue : Volume 11 - 2026, Issue 3 - March

Scribd : https://tinyurl.com/mvucz7b9

DOI : https://doi.org/10.38124/ijisrt/26mar1498

Note : A published paper may take 4-5 working days from the publication date to appear in PlumX Metrics, Semantic Scholar, and ResearchGate.

Abstract : The runoff coefficient is a hydrologic measure that determines the drainage area's storm water runoff capacity based on soil type, soil moisture, and land use. The potential runoff coefficient (PRC) was calculated using a Geographic Information System (GIS) and data from the Kalutara district in Sri Lanka. The runoff depth is going to be computed using the predetermined PRC. Eleven classes, involving four classes of pervious surfaces and seven classes of impervious surfaces, were used to categorize the land use map. The digital elevation model (DEM) with a resolution of 30 meters was used to create the slope map. The soil texture map was produced using the soil map of Sri Lanka's wet zone. The PRC map was then created by combining that previously mentioned three maps, the soil, land use, and slope maps into a single map using GIS software. Using the raster calculator tool in Arc GIS, the average annual rainfall surplus and the runoff coefficient per pixel were used to determine the annual depth of the runoff. The kriging interpolation technique was used to interpolate the rainfall in this study area. PRC's value ranged from 0.13 to 1.0. The range of runoff depth values was 31.0 mm to 479.2 mm. The findings could be applied to the identification of floodplains, the selection of water harvesting sites, and the improvement of water resources management initiatives.

Keywords : Runoff Depth,Potential Runoff Coefficient (PRC), Digital Elevation Model (DEM), Geographical Information System (GIS).

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