Analisis Pengaruh Perubahan Tata Guna Lahan Terhadap Tingkat Erosi dan Sedimentasi Waduk Gonggang, Kabupaten Magetan

Wahyuningsih, Sri (2025) Analisis Pengaruh Perubahan Tata Guna Lahan Terhadap Tingkat Erosi dan Sedimentasi Waduk Gonggang, Kabupaten Magetan. Other thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Waduk Gonggang merupakan terletak di Dusun Ledok, Desa Janggan, Kecamatan Poncol, Kabupaten Magetan, Jawa Timur yang membendung aliran sungai Gonggang yang merupakan anak sungai kali Madiun dengan Daerah Tangkapan Air (DTA) seluas 12,657 km2, dengan potensi tampungan air 1.500.000 m3. Semakin bertambahnya usia waduk, terdapat beberapa permasalahan yang dapat mengganggu fungsi waduk, salah satu permasalahan yang cukup serius yaitu sedimentasi yang terjadi pada Waduk Gonggang ini cukup besar. Sedimentasi ini disebabkan oleh banyak faktor diantaranya, faktor penggunaan lahan yang terjadi pada DAS Gonggang dan keadaan topografi DAS Gonggang yang memiliki kemiringan lereng cukup curam dimana hal tersebut dapat menyebabkan meningkatnya tingkat laju erosi dan sedimentasi yang terjadi. Peningkatan laju erosi dan sedimentasi yang terjadi mengakibatkan berkurangnya usia guna suatu waduk. Proyek akhir ini akan membahas mengenai jumlah erosi, laju erosi, laju sedimentasi hingga volume sedimentasi yang di waduk Gonggang. Tahapan pengerjaan proyek akhir ini meliputi pengumpulan data dan analisa data untuk dapat mengetahui besarnya laju erosi dan sedimentasi yang terjadi. Perhitungan laju erosi dan sedimentasi yang terjadi pada DAS Gonggang menggunakan metode USLE (Universal Soil Loss Equation) berbasis SIG (Sistem Informasi Geografis) serta pemodelan sedimentasi menggunakan software MIKE21. Tahapan proyek akhir ini meliputi pengumpulan data, analisa data, kesimpulan dan saran. Dari hasil analisis dapat diketahui bahwa laju erosi DAS Waduk Gonggang pada tahun 2012 adalah 33,54 ton/ha/tahun dan laju erosi tertinggi terjadi pada tahun 2015 (46,58 ton/ha/tahun), yang juga mencatat total erosi terbesar yaitu 60.172,72 ton/tahun. Penurunan laju erosi mulai terjadi pada tahun 2017 hingga tahun 2024. Selain itu, hasil analisa juga menujukkan bahwa 60% variasi laju erosi dapat dipengaruhi oleh variasi nilai C, sementara sisanya dipengaruhi oleh faktor lain seperti kemiringan lahan, curah hujan, dan jenis tanah. Sehingga dapat diperkirakan usia guna Waduk Gonggang diperkirakan hanya sekitar 19 terhitung sejak tahun 2019 hingga tahun 2037.
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Gonggang Reservoir is located in Ledok Hamlet, Janggan Village, Poncol District, Magetan Regency, East Java, which dams the flow of the Gonggang River, which is a tributary of the Madiun River with a Water Catchment Area (DTA) of 12,657 km2, with a water storage potential of 1,500,000 m3. As the reservoir ages, there are several problems that can disrupt the function of the reservoir, one of the most serious problems is that the sedimentation that occurs in the Gonggang Reservoir is quite large. This sedimentation is caused by many factors, including land use factors that occur in the Gonggang Watershed and the topography of the Gonggang Watershed which has a fairly steep slope where this can cause an increase in the rate of erosion and sedimentation that occurs. The increase in the rate of erosion and sedimentation that occurs results in a reduction in the useful life of a reservoir. This study will discuss the amount of erosion, erosion rate, sedimentation rate to the volume of sedimentation in the Gonggang reservoir. The stages of this study include data collection and data analysis to determine the rate of erosion and sedimentation that occurs. The calculation of the rate of erosion and sedimentation that occurs in the Gonggang Watershed uses the USLE (Universal Soil Loss Equation) method based on GIS (Geographic Information System) and sedimentation modeling using MIKE21 software. The stages of this study include data collection, data analysis, conclusions and suggestions. Based on the analysis, it was found that the erosion rate in the Gonggang Reservoir watershed in 2012 was 33.54 tons/ha/year, with the highest erosion rate occurring in 2015 at 46.58 tons/ha/year. This year also recorded the highest total erosion, reaching 60,172.72 tons/year. A decline in erosion rates began in 2017 and continued through 2024. In addition, the analysis shows that 60% of the variation in erosion rate is influenced by changes in the C factor, while the remaining 40% is affected by other factors such as slope, rainfall, and soil type. Consequently, the estimated functional lifespan of the Gonggang Reservoir is approximately 19 years, calculated from 2019 to 2037

Item Type:	Thesis (Other)
Uncontrolled Keywords:	faktor tata guna lahan, erosi, sedimentasi, USLE, usia guna waduk, land use factors, erosion, sedimentation, USLE, reservoir useful life
Subjects:	T Technology > TC Hydraulic engineering. Ocean engineering > TC167 Dams, reservoirs T Technology > TC Hydraulic engineering. Ocean engineering > TC175.2 Sediment transport
Divisions:	Faculty of Vocational > Civil Infrastructure Engineering (D4)
Depositing User:	Sri Wahyuningsih
Date Deposited:	04 Aug 2025 02:11
Last Modified:	08 Sep 2025 02:38
URI:	http://repository.its.ac.id/id/eprint/126278

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