ANALYSIS AND COMPARISON OF SPATIAL RAINFALL DISTRIBUTION APPLYING DIFFERENT INTERPOLATION METHODS IN PORSUK RIVER BASIN, TURKEY

Porsuk River Basin, located in the Central Anatolia, Turkey, has a drainage area of 10818.41 km2 and total length 460 km, which makes it significant region for variety hydrological hydropower studies. Therefore, is necessary to determine rainfall distribution over basin so that related projects processes, such as dam planning works, can be properly performed. To fulfil this aim, meteorological data gauged between 1927-2015 by 15 different stations within around study were used perform interpolation functions with three widely known spatial methods, namely Thiessen Polygons (TP), Spline (SP) Inverse Distance Weighting (IDW), determination distribution. Moreover, reliability these methods was also evaluated compared terms their Mean Absolute Error (MAE), Square (MSE), Root (RMSE) Correlation Coefficient (R2) values. The results revealed IDW method, general, most appropriate option Basin comparison SP TP MAE, MSE, RMSE R2 values method found 33.359, 1710.385, 41.357 0.7118 respectively. However, displayed smoother at points where rain gauges closer each other or dense.