PENELUSURAN BANJIR DAN KAPASITAS PELIMPAH SITU LEBAKWANGI, BOGOR JAWA BARAT
ABSTRACT: Situ Lebak Wangi
condition is currently very deplorable due to sedimentation and landfilling by
the community. This is being
reinforced by the
presence of land
grabbing to convert
into residential or
agricultural area. Because of
these conditions, Situ Lebak Wangi Design Review was carried out. Flood routing
is necessary in order to plan spillway and reservoir capacity. The purpose
of the flood routing is to determine the magnitude of the inflow and outflow as
well as being stored in the reservoir. The flood discharge values will become
the input to the evaluation of spillway, channel, and volume that can be
accommodated in the reservoir.Calculation of floodroutingn using The Level Pool
Routing Formula: I – Q = dtds, where I is the average inflow (m3/sec) , Q is
the average outflow (m3/sec), S is water storage (m3), and T is the time interval
(hours). The calculation of hydrograph
outflow determined by
the equation: tQ QtI IS Sj j j jj
j 2 21 11. While the spillway
calculations using Strickler formula: Q = A.KS.R.32I21, where Q is the
discharge (m3/sec), A is the area (m2), KS is the Strickler roughness
coefficient, R is the hydraulic radius (m) , and I is the slope of the channel.
Based on the flood routing results and count spillway capacity at Lebak
Wangi, it can be concluded that the discharge of floods the return period 5-years is 9.30 m3/sec. Once through the
reservoir, it will be damped to 3.0 m3/sec. The return period 50-years
discharge is 15.8 m3/sec. This discharge will be damped in the reservoir to
5.30 m3/sec. While the upstream spillway capacity is of 5.5 m3/sec, downstream
capacity decreases to 3.60 m3/sec at 1.3 m water-level height.
Penulis: Edy Sriyono
Kode Jurnal: jptmesindd130321
