MODEL PRAKIRAAN DEBIT AIR DALAM RANGKA OPTIMALISASI PENGELOLAAN WADUK KEDUNG OMBO
Abstract
Abstrak: Pemanfaatan Waduk Kedung Ombo (WKO) sebagai waduk multiguna ternyata masih belum optimal. Hal ini ditandai dengan terjadinya kekurangan air di hilir pada musim kering, dan air melimpas pada musim hujan. Padahal bila dikelola dengan optimal, WKO bisa sebagai sumber air baku dalam pengembangan sistem penyediaan air minum (SPAM) karena hingga saat ini WKO hanya digunakan terbatas untuk irigasi dan PLTA. Adanya permasalahan terhadap ketidakpastian masa depan tersebut, maka perlu dilakukan penelitian pola pengusahaan waduk Kedung Ombo optimal untuk standar operasional Waduk. Pendekatan yang dilakukan dalam pengelolaan waduk adalah dengan metode korelasi spasial (hujan dan debit dan metode diskrit markov yang menggunakan prinsip model stokastik markov 3 kelas. Dengan menggunakan data debit inflow WKO dari tahun 1991-2011 didapatkan beberapa hasil prakiran debit masa depan dengan menggunakan dua komponen hidrologi yaitu hujan dan debit. Pada metode korelasi spasial hujan dan debit dilakukan dengan menguji 5 kombinasi komponen hujan dan debit untuk kemudian dipilih yang mempunyai hasil korelasi tertinggi terhadap debit aktualnya. Dari perhitungan diketahui bahwa kombinasi tipe PQQQ yang mempunyai nilai korelasi tertinggi, yaitu 0,87 sedangkan untuk metode markov didapatkan hasil yang sangat baik dengan koefisien korelasi 0,958. Kemudian nantinya metode markov ini akan digunakan dalam perhitungan manajemen waduk optimal dalam rangka melihat potensi WKO sebagai sumber air baku bagi SPAM di wilayah sekitarnya.
Kata kunci: waduk kedung ombo, korelasi spasial, hujan, debit prakiraan
Abstract: The utilization of Kedung Ombo Reservoir (WKO) as a multipurpose reservoir was considered suboptimum. It is clearly shown by the water shortages at the downstream in the dry season, and an overflown water during the rainy season. If it is managed optimally, WKO can be utilized as a raw water source in the development of drinking water supply system (SPAM) albeit it is only limited to be used for irrigation and hydropower plant today. The uncertainty of the future draws the urgency for a proper study on how to optimize the operational of Kedung Ombo reservoir as standardized operational procedure. The approach taken in the management of the reservoir is the spatial correlation method (rainfall "“ discharge, and Markov discrete method which uses a model that applies the principal of Markov stochastic model 3 classes. By using the inflow discharge data of WKO, taken from the years of 1991-2011, the forecasted discharge value for the future can be obtained through two hydrological components which is rainfall and discharge. The method of the spatial correlation of rain-discharge has five sets of combinations between rain and discharge, where the results with the highest correlation number to its actual value will be opted. From the calculation it is known that the combination of PQQQ type has the highest correlation value, which is 0.87, whereas for the Markov method it obtained a very good results with a correlation coefficient of 0.958. Later on, the Markov method will be used in the optimal reservoir management calculation in order to see the potential of WKO as a source of raw water for SPAM in the surrounding region.
Keywords: Kedung Ombo dam, spatial correlation, presipitation, forecasted water discharge
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