Analysis of Recent Erosion Hazard Levels and Conservation Policy Recommendations for Lesti Subwatershed, Upper Brantas Watershed

Abstract

The reduced age function of Sengguruh Dam/Reservoir due to erosion in the upper of Brantas Watershed (Lesti Subwatershed area) interferes with its role in flood control, irrigation water supply and the supply of most of the hydroelectricity in East Java Province, Indonesia. This study aims to estimate erosion, analyze the interrelationship of the causative factors and provides environmental conservation direction. The research method uses mixed methods. The quantitative method of erosion rates is done by calculating the Modify Universal Soil Loss Equation which is supported by GIS tools. The qualitative method is carried out with questionnaires and interviews in the Lesti Subwatershed area. The results showed that the current erosion rate in each ha of land (average) in the Lesti Subwatershed was 153,868 tons / ha / year (exceeding the tolerable erosion rate of 30 tons / ha / year). The rate of erosion in the Lesti Subwatershed has always increased in the last 14 years. Of the 12 Subdistricts in the Lesti watershed, as many as 6 Subdistricts are identified as having high levels of Erosion Hazards so that they were a priority to be handled, namely in the Wajak, Dampit, Tirtoyudo, , Gedangan, Sumbermanjing Wetan and Bantur Subdistricts. Dampit Subdistrict, Turen Subdistrict and Gondanglegi Subdistrict also face behavioral problems and high population pressure compared to other Subdistricts. Research also shows that there is a relationship between erosion and knowledge, attitudes and behavior of the community in the form of population pressure and land use patterns. It is recommended that environmental conservation directives focus on these 6 Sub-districts through the application of soil and water conservation. The results of spatial analysis at priority locations suggest conservation measures in the form of law enforcement or counseling, and community empowerment to increase the ability and independence of the community through providing access to resources, education, and training.

Analisis Sebaran Limpasan Permukaan pada Sub DAS Lesti Sebagai Pertimbangan Konservasi Hulu DAS Brantas

“…Proses deleniasi dilakukan dengan bantuan tools Sistem Informasi Geografis (SIG), khususnya software ArcGIS. Deleniasi dimulai dengan mengubah peta kontur menjadi DEM, kemudian menentukan arah aliran atau flow direction, akumulasi aliran (flow accumulation), pendefinisian jaringan sungai secara sintetik, penentuan outlet kemudian yang terakhir pendefinisian DAS dan kalkulasi parameter DAS (Pambudi et al, 2021).…”

“…Kutipan: Pambudi, A.S., Moersidik, S.S., Karuniasa, M. (2021). Analisis Sebaran Limpasan Permukaan pada Sub DAS Lesti Sebagai Pertimbangan Konservasi Hulu DAS Brantas.…”

Lithium Separation from Geothermal Brine to Develop Critical Energy Resources Using High-Pressure Nanofiltration Technology: Characterization and Optimization

“…Studies show that geothermal brine contains many valuable minerals such as Si, Li, K, etc., that need to be removed. Dieng is one of the hot geothermal springs in Indonesia, which has been found to contain salt water with a lithium concentration of 4060 ppm [ 13 ]. This statement proves that geothermal salt water has the potential to be an alternative source of lithium in the future.…”

Selecting the accurate hydrological method for estimating peak discharge in the Lesti River Catchment Area, Malang Regency, East Java Province, Indonesia

“…This crucial task involves determining the maximum volume of water flowing through a river or channel during a specific period, usually during extreme weather events such as heavy rainfall or snowmelt (Saadi et al, 2021). Accurately predicting peak discharge is vital for designing hydraulic structures, including dams, bridges, culverts, and flood control systems, as it helps ensure that these structures can effectively handle to anticipate water flow and prevent potential damage or failure (Avila and Ávila 2016;Pambudi et al, 2021). Gericke and Smithers, 2014).…”

“…The accuracy of estimation was influenced by various factors, including the availability and quality of data, the scale of analysis, the assumptions made in the estimation methods, and probability distributions. Therefore, this paper examines various methods, including SUH, Melchior, and the Rational method, to determine the varied peak discharge values in the Lesti River (Februanto et al, 2021;Pambudi et al, 2021; Roestamy and Fulazzaky 2021). The main objective of this study is to analyze the most relatively accurate method for peak discharge estimation.…”