ANALISIS VOLUME LIMPASAN PERMUKAAN AKTUAL DAN TEORITIS PADA LAHAN MIRING MENGGUNANAKAN METODE SCS-CN DI DTA CITARIK HULU

Sari

Surface runoff that occurs on agricultural land causes agricultural land to experience dryness due to insufficient water availability. The amount of runoff occurs on sloping land with high rainfall. The purpose of this study was to determine the amount of surface runoff with a certain curve number. Three designs were used in this study, namely design one with the previous groundwater content at average conditions (AMC II), design two using AMC conditions throughout the plot and the third design using graphs. The results of these three designs were tested using the RMS-E statistical test to determine the accuracy of the SCS-CN model used with the actual surface runoff. The largest actual surface flow occurred in the third plot plants, each of 206.11 mm, 200.77 mm and 144.23 mm with a land slope of 18%. The CN value that is close to the actual runoff flow amount is based on a graph with plot 1 CN value of 87, plot 2 CN value of 89 and plot 3 CN value of 89 with 5%, 12% and 18% slope respectively. This estimation method is said to be accurate as evidenced by the relatively small RMS-E value of 0.12. This CN value is used to predict the total runoff volume in the upstream Citarik catchment area. Keywords : Runoff, SCS-CN, Curve Number