ANALISA PENGARUH PERUBAHAN PENUTUPAN LAHAN TERHADAP DEBIT SUNGAI SUB DAS METRO DENGAN MENGGUNAKAN PROGRAM ARCSWAT - Harifa, Ayisya Cindy; Sholichin, Moh.; Prayogo, Tri Budi (Jurnal Teknik Pengairan: Journal of Water Resources Engineering, 2017)
ABSTRAK: DAS memiliki karakteristik yang spesifik sebagai daerah hidrologi, berkaitan dengan unsur utamanya seperti jenis tanah, tata guna lahan, topografi, kemiringan dan panjang lereng. Analisa karakteristik tersebut dilakukan dengan menggunakan pemodelan Soil Water Assesment Tool (SWAT). Tujuan penelitian ini adalah, mengidentifikasi kondisi eksisting tahun 2014, mengetahui pola perubahan lahan tahun 2002, 2006, 2009, dan 2014, mengetahui dampak perubahan terhadap Curve Number, limpasan permukaan dan sedimen, menilai kondisi DAS. Hasil simulasi menunjukkan bahwa perubahan penutupan lahan menyebabkan nilai CN, limpasan dan debit sungai semakin besar. Nilai CN berada di kisaran 11 – 96, debit rata-rata tahunan berkisar antara 1.923 – 3.591 m3/dt, dan besarnya limpasan yang terjadi sebesar 3.03 – 1914.28 mm. Berdasarkan hasil kalibrasi, hasil menunjukkan p-factor sebesar 0.85, dan p-factor hasil validasi sebesar 0.83, sehingga simulasi dianggap valid. Penilaian kinerja DAS menunjukkan bahwa di wilayah studi dalam kategori kinerja yang buruk. Keyword: Penutupan Lahan, Limpasan, SWAT ABSTRACT: Watershed as hydrologic area, characterized by specific element such as soil, land cover, topographic, land slope and length of slope. Soil Water Assessment Test (SWAT) is a suitable hydrologic modeling system to analyze many character in watershed. The aim of this study are to identified land cover in 2014, to determine the pattern of land cover changes in 2002, 2006, 2009 and 2014, determine the impact of land cover changes related to curve number, surface runoff, and sedimentation, assess the watershed condition. Simulation result showed that land cover changes have resulted in corresponding increase in curve number, surface runoff, and stream flow. Curve number was about 11 – 96, yearly discharge was about 1.923 – 3.591 m3/s, and surface runoff was about 3.03 – 1914.28 mm. Calibration result showed that p-factor value is 0.85, and validation result showed that p-factor value of 0.83, it means that simulation was valid. Base on watershed assessment, concordance of land cover and surface runoff in the bad category. Keyword: Land Cover, Surface Runoff, SWAT