SIMULASI KOMPUTER PENGARUH RELOKASI KERAMBA JARING APUNG TERHADAP KANDUNGAN NITRAT DI DALAM AIR WADUK JATILUHUR
Abstract
Abstrak: Kegiatan keramba jaring apung yang dikembangkan di Waduk Jatiluhur berfungsi untuk memenuhi kebutuhan pangan. Namun, akibat pertumbuhannya yang cepat dan tidak terkendali maka kegiatan keramba jaring apung telah menjadi sumber pencemar utama, termasuk nitrat, dalam Waduk Jatiluhur. Nitrat sebagai salah satu nutrien yang dapat digunakan langsung oleh biota air merupakan salah satu pemicu terjadinya eutrofikasi dalam waduk. Degradasi kualitas air akibat eutrofikasi dapat mengganggu fungsi waduk sebagai pembangkit listrik dan penyedia pasokan air baku air minum serta irigasi pertanian. Upaya yang dapat dilakukan untuk mengatasi hal tersebut adalah dengan merelokasi keramba jaring apung dari daerah disekitar outlet waduk menuju lokasi yang lebih jauh dari outlet waduk. Untuk melihat sejauh mana pengaruh kegiatan keramba jaring apung dalam waduk maka dilakukan simulasi konsentrasi nitrat dalam air waduk dengan menggunakan pendekatan segmentasi vertikal. Simulasi konsentrasi nitrat juga dilakukan dengan menerapkan skenario perbaikan berupa relokasi keramba jaring apung. Simulasi terhadap skenario perbaikan dilakukan sebagai suatu langkah optimasi dalam rangka mereduksi konsentrasi nitrat di outlet waduk. Hasil simulasi menunjukkan bahwa upaya pengelolaan dengan merelokasikan keramba jaring apung menuju lokasi yang lebih jauh dari outlet wasuk telah berhasil menurunkan konsentrasi nitrat di segmen terakhir waduk. Dari hasil simulasi didapat bahwa reduksi konsentrasi nitrat tertinggi didapatkan dengan cara merelokasi keramba jaring apung dari segmen kedelapan menuju segmen kedua. Dengan merelokasikan keramba jaring apung menuju segmen kedua sebanyak 20%, 50%, dan 100% dari jumlah keramba jaring apung di segmen kedelapan masing-masing telah berhasil menurunkan konsentrasi nitrat sebesar 16,67%, 41,52%, dan 82,37% pada segmen terakhir waduk.
Kata kunci: keramba jaring apung, nitrat, Waduk Jatiluhur, kualitas air.
Abstract: Fish cagesin Jatiluhur reservoir are developed in order to meet the food demands. However, due to its rapid and uncontrollable growth, fish cages turn to be the major pollutant source in Jatiluhur reservoir. Nitrate, as one of nutrient that can be use directly by aquatic biota, is one of the factor that trigger eutrophication in a reservoir. Water quality degradation caused by eutrophication can hinder reservoir function as a hydro-electric generation and water resources that provided raw water for drinking water and irrigation. An effort that is possibly done to overcome the problem was by relocating the fish cages to upstream site. The simulation of nitrate concentration that approached by vertical segmentation then being done to see to what extent fish cage number affected the nitrate concentration in reservoir. The simulation was also being done by implementing improved scenario. The simulation with improved scenario carried out as an optimization measure in order to reduce the nitrate concentration in reservoir outlet. The results of the simulation indicated that by relocated the fish cage to further location from reservoir outlet has been successful reduce nitrate concentration in the last segment of the reservoir. The highest nitrate concentration reduction was obtained when the fish cage was relocated from the eighth segment to the second segment of the reservoir. By relocate the fish cage as much as 20%, 50%, and 100% of the number of fish cage in the eighth segment the nitrate concentration reduction in the last segment is 16.67%, 41.52%, and 82.37% respectively.
Keywords: fish cage, nitrate, Jatiluhur reservoir, water quality.
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