Penelitian ini bertujuan untuk melakukan simulasi model SWAT dalam menghitung besarnya laju erosi DAS, menguji kesesuaian model dalam memprediksi erosi, serta menentukan skenario penggunaan lahan yang paling optimal menurunkan laju erosi. Penelitian ini dilakukan di DAS Deli, Sumatera Utara. Pada penelitian ini analisis SWAT dilakukan dengan bantuan Sistem Informasi Geografi (SIG) melalui 4 proses yaitu delineasi, pembentukan Hydrological Response Unit (HRU), pengolahan data dan simulasi, serta proses visualisasi. Hasil penelitian menunjukkan besarnya erosi rata-rata DAS Deli adalah 410,72 ton/ha/tahun. Hasil ini menunjukkan DAS Deli termasuk kedalam Tingkat Bahaya Erosi (TBE) kategori Berat dengan kriteria sangat berat 37,04%, berat 17,07%, sedang 21,46%, ringan 17,38%, dan sangat ringan 7,04%. Uji validasi model menunjukkan bahwa ada hubungan positif antara debit model dan observasi dimana persentase perbedaan nilainya sangat kecil yang artinya besarnya debit model hampir sangat mendekati besarnya debit observasi, serta model dikategorikan sangat baik dalam melakukan simulasi debit aliran harian pada Sungai Deli. Metode skenario adalah berdasarkan analisis TBE. Hasil skenario penggunaan lahan berhasil menurunkan laju erosi DAS Deli 34,78% menjadi 267,88 ton/ha/tahun.This study aims to conduct SWAT model simulation calculation of the rate of erosion of the watershed, testing the suitability of the model in predicting erosion, land use scenarios and determine the most optimal decrease the rate of erosion. This research was conducted in the watershed Deli, North Sumatra. In this study, SWAT analysis performed with the help of Geographical Information Systems (GIS) through 4 delineation process, namely, the establishment of Hydrological Response Unit (HRU), data processing and simulation, as well as the visualization process. The results show the average amount of erosion DAS Deli is 410.72 ton/ha/year. These results indicate DAS Deli included into Erosion Hazard Level (TBE) weight category with very strict criteria 37.04%, 17.07% by weight, were 21.46%, 17.38% mild and very mild 7.04%. Test model validation indicates that there is a positive relationship between the discharge and observation models where the percentage difference in value is very small, which means the amount of discharge model is very very close to a number of discharge observations, and models are categorized very good at simulating the daily flow rate at the Deli River. The scenario method is based on analysis of TBE. The results of land use scenarios managed to reduce the rate of erosion of the watershed Deli 34.78% to 267.88 tons/ha/year.
The Application of a Modified Version of the SWAT Model at the Daily Temporal Scale and the Hydrological Response unit Spatial Scale A Case Study Covering an Irrigation District in the Hei River Basin
