The topography layer is created by calculation of the slope value from the national topographic data. S values were classified into DRASTIC S values from 1-10. Due the generally flat topography, the majority of the catchment is assigned the higher âTâ-values.
The model was created using National topographical information from OSI. The slope was calculated using ERSI ArcMap 10.5 and QGIS as a shapefile and converted into .tiff format