Electronic Theses and Dissertation

DAS Krueng Mane merupakan suatu DAS seluas 415,98 km2. Krueng Mane direncanakan sebagai lokasi intake Sistem Penyediaan Air Minum (SPAM) Kota Lhokseumawe tepatnya di Kecamatan Sawang pada koordinat 5°11'26.8" LU – 96°54'51.8" BT. Di beberapa tempat pada DAS Krueng Mane penggunaan lahan telah berubah dari yang semula hutan, menjadi sawah, perkebunan sawit, dan perumahan penduduk. Perubahan tata guna lahan yang didukung oleh curah hujan yang tinggi berpotensi meningkatkan pengikisan tanah atau laju erosi, serta dapat mengakibatkan pendangkalan sungai yang disebabkan oleh sedimentasi. Sedimentasi dapat mengendap dan menyebabkan gangguan pada pengoperasian pintu intake SPAM. Penelitian ini bertujuan untuk mengetahui nilai laju erosi lahan, sedimentasi, dan sebaran Tingkat Bahaya Erosi (TBE) DAS Krueng Mane. Perhitungan erosi dilakukan menggunakan Metode Universal Soil Loss Equation (USLE) berbasis Sistem Informasi Geografis (SIG) dan besar sedimen dihitung berdasarkan nilai Sediment Delivery Ratio (SDR). Dari hasil perhitungan diperoleh laju erosi lahan DAS Krueng Mane sebesar 17.614,82 ton/ha/tahun dan sedimentasi sebesar 1.620,56 ton/ha/tahun atau 67.412.186,16 ton/tahun. Tingkat bahaya erosi DAS Krueng Mane didominasi oleh kelas sangat ringan sebesar 53,58% dengan luas 22.287,46 Ha, kemudian diikuti kelas ringan (16,94%), sedang (23,00%), berat (5,40%), dan sangat berat (1,08%). Persentase TBE sangat ringan terbesar terjadi pada tutupan lahan dengan kerapatan tajuk yang baik, tanah dengan erodibilitas rendah, serta kemiringan lereng yang landai. Sedangkan TBE sangat berat terjadi pada lahan dengan kecuraman tinggi dan lahan terbuka akibat dari tidak adanya vegetasi penutup lahan yang dapat menghambat limpasan dan pengangkutan partikel tanah
Kata Kunci: DAS Krueng Mane, erosi, sedimentasi, Tingkat Bahaya Erosi, USLE, SIG

Krueng Mane watershed is a watershed with an area of 415.98 km2. Krueng Mane is planned as the location for the intake of the Drinking Water Supply System (SPAM) of Lhokseumawe City, precisely in Sawang District at coordinates 5°11'26.8" North Latitude – 96°54'51.8" East Longitude. In several places in the Krueng Mane watershed, land use has changed from forest, to rice fields, oil palm plantations, and housing for residents. Changes in land use supported by high rainfall have the potential to increase soil erosion or erosion rates, and can result in silting of rivers caused by sedimentation. Sedimentation can settle and cause interference with the operation of the SPAM intake door. This study aims to determine the value of the rate of land erosion, sedimentation, and the distribution of the Erosion Hazard Level (EHL) in the Krueng Mane watershed. Erosion calculations were carried out using the Universal Soil Loss Equation (USLE) method based on a Geographic Information System (GIS) and the sediment size was calculated based on the value of the Sediment Delivery Ratio (SDR). From the calculation results, the erosion rate of the Krueng Mane watershed is 17,614.82 tons/ha/year and sedimentation is 1,620.56 tons/ha/year or 67,412.186.16 tons/year. The erosion hazard level of the Krueng Mane watershed is dominated by very light class of 53.58% with an area of 22,287.46 Ha, followed by light class (16.94%), moderate (23.00%), heavy (5.40%), and very heavy (1.08%). The highest percentage of very light EHL occurred on land cover with good canopy density, low erodibility soil, and gentle slopes. Meanwhile, EHL is very heavy on land with high steepness and open land due to the absence of land cover vegetation that can inhibit runoff and transport of soil particles. Keywords: Krueng Mane watershed, erosion, sedimentation, Erosion Hazard Level, USLE, GIS