Prediksi Erosi Menggunakan Model USLE pada Kegiatan Rehabilitasi Hutan dan Lahan (RHL) di Sub-Sub DAS Cibitung dan Sub-Sub DAS Cisembung, DAS Citarum

Abstract

DAS Citarum merupakan sumberdaya air yang sangat penting bagi Provinsi Jawa Barat, tetapi kondisinya sangat memprihatinkan akibat pencemaran dan erosi. Penelitian ini bertujuan memprediksi erosi di Sub-Sub DAS Cibitung dan Sub-Sub DAS Cisembung, DAS Citarum serta menyusun arahan pengelolaan lahan berdasarkan konservasi tanah dan air. Penelitian ini dilakukan dengan memprediksi erosi eksisting pada Sub-Sub DAS Cibitung dan Sub-Sub DAS Cisembung, prediksi erosi dengan skenario kegiatan Rehabilitasi Hutan dan Lahan (RHL) dan skenario arahan pengelolaan lahan sebagai skenario alternatif lain. Hasil prediksi erosi pada kondisi eksisting di Sub-Sub DAS Cibitung sebesar 38,02 ton ha-1 tahun-1 dan di Sub-Sub DAS Cisembung sebesar 126,12 ton ha-1 tahun-1. Tolerable soil loss di Sub-Sub DAS Cibitung sebesar 29,08 ton ha-1 tahun-1 dan di Sub-Sub DAS Cisembung sebesar 19,99 ton ha-1 tahun-1. Kegiatan RHL dari BPDASHL Citarum-Ciliwung diprediksi menurunkan erosi di Sub-Sub DAS Cibitung sebesar 18,7% dan menurunkan erosi di Sub-Sub DAS Cisembung sebesar 91,38%. Arahan pengelolaan lahan dari kegiatan RHL yang dimodifikasi diprediksi dapat menurunkan erosi sebesar 31,45% di Sub-Sub DAS Cibitung dan menurunkan erosi sebesar 86,95% di Sub-Sub DAS Cisembung. Arahan pengelolaan lahan dengan teknik konservasi tanah dan air diprediksi dapat menurunkan erosi sebesar 90,58% di Sub-Sub DAS Cibitung dan menurunkan erosi sebesar 97,03% di Sub-Sub DAS Cisembung.

The Citarum watershed is a very important water resource for West Java Province, but its condition is very critical due to pollution and erosion. The research aims were to predict the erosion in the Cibitung and Cisembung Subwatersheds based on existing, forest and land rehabilitation condition, and to arrange land management based on soil and water conservation. This research was conducted by computing the prediction of existing erosion, prediction of erosion based on forest and land rehabilitation activity and the land management as another alternative scenario in the Cibitung and Cisembung Sub-watersheds. The results show that the prediction of erosion in the existing conditions in the Cibitung Sub-watershed is 38,02 tonnes ha-1 year-1 and in Cisembung Subwatersheds is 126,12 tonnes ha-1 year-1. Tolerable soil loss in Cibitung Subwatershed is 29,08 tons ha-1 year-1 and in Cisembung Sub-watershed is 19,99 tons ha-1 year-1. Forest and land rehabilitation activities from BPDASHL Citarum- Ciliwung are predicted to reduce the erosion in the Cibitung Sub-watershed by 18,7% and reduce the erosion in Cisembung Sub-watershed by 81,94%. The direction for land management by modificated the forest and land rehabilitation activities are predicted to reduce erosion by 31,45% in the Cibitung Subwatershed and reduce erosion by 91,38% in the Cisembung Sub-watershed. The direction for land management by used water and soil conservation’s technic are predicted to reduce erosion by 90,58% in the Cibitung Sub-watershed and reduce erosion by 97,03% in the Cisembung Sub-watershed.