Perencanaan DED Retarding Basin di Desa Tambak Beras

Planning of DED Retarding Basin in Tambak Beras Village

Abstract

The Kali Lamong Watershed (DAS) is experiencing critical hydrological conditions due to an imbalance between the river’s peak discharge, which reaches 700 m³/s, and its storage capacity of only about 250 m³/s. This imbalance has triggered annual floods affecting the regions of Gresik, Lamongan, and Mojokerto. One proposed solution is the construction of a retarding basin in Tambak Beras Village, Cerme District, Gresik Regency. This study aims to prepare a Detail Engineering Design (DED) document for the retarding basin, which can serve as a technical reference for construction implementation and ensure that the resulting plan supports the effectiveness and efficiency of flood control. The research method includes hydrological analysis, hydraulic analysis, embankment design planning, sluice gate design, and modeling using hydraulic software. The results indicate that rainfall data from various observation stations, after consistency and stationarity testing, provide a valid basis for rainfall intensity and design flood discharge analysis. The embankment design considers the selection of soil, gravel, and stone materials suited to field conditions, as well as stability evaluations under dry, saturated, and seismic conditions. Overall, the DED retarding basin design is expected to reduce the peak flood discharge of the Kali Lamong River and enhance protection for settlements, agricultural land, and infrastructure in the affected areas.