Analisis Kebutuhan Luasan dan Kapasitas Volume Tampung Kolam Detensi sebagai Upaya Pengendalian Banjir di Kecamatan Medan Selayang

Abstract

The significant growth in the population of Medan, over time resulted in a change in the city's land use which initially functioned as a water catchment area turned into a residential area with minimal infiltration. The high intensity of rainfall accompanied by changes in land use and inadequate drainage systems in Medan Selayang District resulted in surface runoff flowing towards the river body. With the condition of the river body experiencing siltation due to sedimentation, the elevation of the river spring increases, which has an impact on the inundation of residential areas around the river body. One of the alternatives in overcoming the flood disaster structurally in Medan Selayang District is by planning the construction of a detention pond that functions to temporarily collect rainwater and cut the peak discharge of the Selayang river flood. Then in determining the amount of discharge to plan the capacity of the storage volume and the need for the area of the detention pond, a hydrological analysis was carried out based on the rain that occurred in the detention pond area. The analysis carried out by the Rational method obtained a peak discharge of 33.46 m3⁄s and using the Nakayasu method obtained a peak discharge of 43.69 m3⁄s. So it is planned a detention pond with storage capacity of 112000 m3 and an area requirement of 3.3 hectares with a pool depth of 3 m.