MODEL OF PEAK DISCHARGE REDUCTION USING SIDE CHANNEL

Special Region of Jakarta Capital as downstream area of Ciliwing river encounter overflow of the river anually. The watershed area start from upstream to downstream of the Ciliwung river had encounter degradation, from landuse to the riverbank of Ciliwung river had more then 20% degradation. Ciliwung river devided into 2 area, upstream Ciliwung, middle Ciliwung area and downstream Ciliwung. This research was done in the middle section of the Ciliwung river, starting from Katulampa Weir until the bridge of Ciliwung Kepala Dua. This research purpose are to reduce the peak of the hydrograph discharge graphic in the middle area by installing Side channel with the capacity of 96, 956 m3 with the flood discharge of 538.64 m3 /sec. the analysis of the research using Nakayassu hydrograph and simulated using iRIC software. Instalation of side channel are based on the elevation of the area and the potency of a green area in the middle area therefore the Kalo Baru 2, Sugutamu, Cikumpa and Ciparigi area are choosen. Declining of the Nakayussu hydrograph graphic are 12 - 15% with the callibration using iRIC Software simulation shows 14.76% and deceleration of the flow time until 15,200 second. The acquired mathematic equation are Y = 4.723X1+0.00005X2+62.925 with Y as the declining of the flood discharge, X1 as the number of side channel and X2 as the volume of the reservoirs.