Prosedur Kalibrasi dan Validasi Model SMAR untuk Mendeskripsikan Proses Hujan Aliran di Sub-DAS Rawatamtu
DOI:
https://doi.org/10.5614/jts.2012.19.3.7Keywords:
Model SMAR, Prosedur, Kalibrasi, dan Validasi.Abstract
Abstrak. Model SMAR (Soil Moisture Accounting Rainfall Model) merupakan salah satu model hidrologi pada RRL (Rainfall Runoff Library) yang dapat digunakan untuk menghitung aliran permukaan (Run Off) dari suatu DAS. Data masukan utama untuk model adalah data hujan dan evapotranspirasi. Artikel ini membahas prosedur kalibrasi dan validasi model untuk mendeskripsikan proses hujan - aliran pada skala harian. Artikel juga memaparkan tentang manfaat user-interface dan visualisasi yang ada pada software (model) tersebut. Model dikalibrasi menggunakan data debit yang diperoleh dari sub-DAS Rawatamtu (Jawa Timur). Kombinasi dua metode (generic dan manual) digunakan selama proses kalibrasi dan validasi. Kalibrasi dilakukan pada separuh periode rekaman yang tersedia, sedangkan validasi dilakukan pada separuh periode yang ke dua. Hasil kalibrasi dan validasi dievaluasi menggunakan kriteria: Koefisien Nash-Sutcliffe, Koefisien korelasi (correlation coefficient) danperbedaan Run Off (difference in Run Off). Kalibrasi dan validasi menggunakan metode generic maupun manual menunjukkan bahwa model mampu mereproduksi proses utama dari Hujan menjadi Aliran (debit terhitung) pada sub-DAS tersebut. Hasil juga menunjukkan bahwa performance model kurang optimal pada periode validasi, hal ini dikarenakan keterbatasan data yang digunakan. Data yang lebih lengkap diperlukan untuk mengevaluasi performance model.
Abstract. The Soil Moisture Accounting Rainfall Model (SMAR) is one of Rainfall Runoff Library Models (RRL) used to calculate Run-Off from rainfall and evapotranspiration data. This article shows the procedure to calibrate the model. Furthermore, this article also show the benefit of software fitur and user interface. Model is calibrated and validated using discharge data otained from Rawatamtu sub-Watershed (East Java). Two methodes (generic and manual) were exploited for the calibration and validation procceses. The result was evaluated by using the criteria of: Nash-Sutcliffe Coefficient, Coefficient of Correlation and difference in run-off. Calibration is conducted at the first half of recording periods, while validation is conducted at the second half of recording
periods. The result shows that both generic and manual method can describe Rainfall to Run-Off process of the watershed, during calibration periode. However, during validation period model performance is not satisfied, due to the limit of data used. More data is needed to evaluate the model performance.
References
Kachroo R.K., and Liang, 1992, River Flow Forecasting. Part 5. Applications of Conceptual Model. Journal of Hydrology. 133, 141 - 178.
Nash J.E., 1960, A Unit Hydrograph Study with Particular reference to British Catchment, Proceedings of the Institute of Civil Engineers, 17, 249 - 282.
O'Connell, P.E., Nash, J.E and Farrel, J.P., 1970, Riverflow Forecasting through Conceptual Models, part2. The Brosna Catchment at Ferbane. Journal of Hydrology. 10 : 317 - 329.
Podger, Geoff, 2004, Rainfall Run Off Library Versi 1.05 User Guide, Department of Infrastructure, Planning and Natural Resources; CRC for Catchment Hydrology.
Tuteja, N.K. and O'Connor, C., 1999, A Quasi Physical Snowmelt Run-off Modelling System for Small Catchment, Hydrological Processes, 13 (12/13): 1961 - 1975.
