STUDY OF THE IMPACT OF LAND USE CHANGES IN DARMA RESERVOIR CATCHMENT AREA ON DARMA RESERVOIR SEDIMENT INFLOW

• Main Author: Raharsiwi, Chyntia
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/86609
• Institution: Institut Teknologi Bandung

One of the key considerations in reservoir management is the impact of land use changes within the reservoir's watershed area (DTA). Land use changes are driven by human activities, such as population growth, which increases the demand for new settlements. The conversion of land from forests to non-forested areas and from agricultural to nonagricultural uses significantly affects soil erosion in the watershed, leading to increased sediment inflow into the reservoir. The aim of this study is to assess the impact of land use changes on sedimentation in the DTA of Darma Reservoir. The findings will determine the functional lifespan of Darma Reservoir based on sediment inflow resulting from land use practices.. Sedimentation modeling in this study was conducted using SSIIM-2 (Sediment Simulation in Intakes with Multiblock Option). The input flow rates for the SSIIM model were derived from the river discharges contributing to Darma Reservoir. These discharges were analyzed using the NRECA method and allocated to each sub-watershed (sub-DAS) based on their respective catchment areas. From flow and sedimentation simulations using monthly discharge data over a 7-year period (2012–2018), the average annual sedimentation volume was estimated at 356,358.420 m³/year. Analysis of sediment distribution at the dead storage level (elevation +693.540) revealed that only 3.667% of the total sediment inflow reached the dead storage zone located in the downstream area of the reservoir. These results can be used to develop effective sedimentation management strategies and to analyze sedimentation rates relative to the dead storage capacity of Darma Reservoir in future studies.