Perbandingan Metode Alih Ragam Hujan Menjadi Debit dengan FJ. Mock dan NRECA di DAS Gandong Kabupaten Magetan

Syelawati Citra Kartika Nurviana
Ery Suhartanto
Donny Harisuseno

Jurnal Teknologi dan Rekayasa Sumber Daya Air
Vol. 3 No. 1 (2023): Jurnal Teknologi dan Rekayasa Sumber Daya Air (JTRESDA)

Abstract: The process of converting rainfall to discharge located in Gandong watershed is carried out using FJ. Mock and NRECA methods. After that, calibration and validation test was carried out using discharge data (AWLR) on modeled discharge, to find out which method was compatible with character Gandong watershed. The best result is NRECA method, with value when best calibration process in 8 years, produces value of MAE = 0.029, NSE = 0.982, R = 0.992, Kr = 1.11%. Best validation process in 1 year, produces value of MAE = 0.100, NSE = 0.857, R = 0.942, Kr = 5.15% with parameters value of PSUB = 0.98, GWF = 0.0001–0.003, reduction coefficient = 0.9, W0 = 1218.87 mm, initial groundwater storage = 200 mm. As well as for FJ. Mock method got best calibration in 7 years, produces value of MAE = 0.020, NSE = 0.993, R = 0.997, Kr = 0.69%. And best validation in 1 years, produces value of MAE = 0.787, NSE = -29.048, R = 0.405, Kr = 95.21% with parameters value of m = 30%-50%, i = 0.9, k = 0.034–0.988, SMC = 200 mm, ISM = 100 mm, Vn-1 = 100 mm.Abstrak: Proses pengalihragaman hujan ke debit yang berlokasi di DAS Gandong dilaksanakan memakai metode FJ. Mock dan NRECA. Setelah itu dilakukan uji kalibrasi dan validasi memakai data debit (AWLR) terhadap debit hasil permodelan untuk mengetahui metode mana yang memiliki kesesuaian dengan karakter dari DAS Gandong. Hasil terbaik pada penelitian ini adalah Metode NRECA dengan nilai ketika proses kalibrasi terbaik periode 8 tahun menghasilkan nilai MAE = 0.029, NSE = 0.982, R = 0.992, Kr = 1.11%.  Ketika proses validasi terbaik periode 1 tahun menghasilkan nilai MAE = 0.100, NSE = 0.857, R = 0.942, Kr = 5.15% dengan nilai parameter PSUB = 0.98, GWF = 0.0001–0.003, koefisien reduksi = 0.9, W0 = 1218.87 mm, nilai tampungan air tanah awal = 200 mm. Serta untuk metode FJ. Mock didapatkan kalibrasi terbaik periode 7 tahun menghasilkan nilai MAE = 0.020, NSE = 0.993, R = 0.997, Kr = 0.69%. Dan validasi terbaik periode 2 tahun menghasilkan nilai MAE = 0.787, NSE = -29.048, R = 0.405, Kr = 95.21% dengan nilai parameter m = 30%-50%, i = 0.9, k = 0.034–0.988, SMC = 200 mm, ISM = 100 mm, Vn-1 = 100 mm.