Pencirian debit aliran sungai citarum hulu

Abstract

Citarum is one of strategic rivers in West Java. In the upper part of this river, there are 3 large dams (Saguling, Cirata, and Jatiluhur) which operates hydroelectric power that supply ± 20% electricity needs of Java-Bali area. Run off discharge of the river are fluctuating widely so greatly affect the performance of electricity production, supply of irrigation, and household water in the downstream area. The research aims to identify character of river discharge of Citarum Hulu and its relation with land use changes and farm management. River discharge were analyzed at the inlet of Saguling dam in Kampung Nanjung and some stream monitoring stations located in Ciwidey, Cisangkuy, and Cikapundung-Gandok. River discharge was highly fluctuating. In the peak of rainy season the flow rate can reach 578 m3/sec which caused flooding in several area such as Majalaya, Banjaran, and Dayeuhkolot. In contrary, in dry season the flow was very low, about 2.7 m3/sec, causing drought, failure of rice harvest, and reduced water supply to hydropower plant of Saguling. In addition to affecting rainfall patterns, the flow rate fluctuations was also influenced by pattern of land use and management. Land utilization that was not in accordance with the land capability was the main cause of land degradation which in turn would decrease hydrology function of watershed to control river discharge in rainy season.

Sungai Citarum merupakan sungai strategis di wilayah Jawa Barat. Pada bagian hulu sungai tersebut terdapat 3 waduk besar (Saguling, Cirata, dan Jatiluhur) yang mengoperasikan PLTA dan memasok ± 20% kebutuhan listrik Jawa-Bali. Fluktuasi debit aliran sungai Citarum sangat memengaruhi kinerja produksi listrik dan penyediaan air irigasi dan air bersih di wilayah hilir. Penelitian ini bertujuan mengidentifikasi ciri debit aliran sungai Citarum Hulu dalam kaitannya dengan perubahan penggunaan lahan dan pengelolaan lahan pertanian. Debit aliran dianalisis pada inlet Waduk Saguling di Kampung Nanjung, dan beberapa stasiun pengamat arus sungai yang terletak di Ciwidey, Cisangkuy, dan Cikapundung-Gandok. Fluktuasi debit aliran Sungai Citarum Hulu sangat tinggi. Pada puncak musim hujan debit aliran dapat mencapai 578 m3/dt sehingga menimbulkan banjir di wilayah Majalaya, Banjaran, dan Dayeuhkolot. Sebaliknya pada musim kemarau debit aliran sangat rendah, sekitar 2,7 m3/detik sehingga menyebabkan kekeringan dan kegagalan panen padi serta berkurangnya pasokan air ke PLTA Saguling. Fluktuasi debit aliran sungai yang sangat tinggi selain dipengaruhi oleh pola curah hujan juga dipengaruhi oleh pola pemanfaatan dan pengelolaan lahan. Penggunaan lahan yang tidak sesuai dengan kapasitas daya dukung lahan merupakan faktor pendorong utama terjadinya degradasi lahan yang pada gilirannya menurunkan fungsi hidrologi daerah aliran sungai dalam mengendalikan debit aliran permukaan.