IDENTIFIKASI LAHAN RESAPAN (KOLAM RETENSI) DALAM PENANGANAN BANJIR DI KAWASAN SIMPANG JOHAR-YASMIN

Abstract

Simpang Johar-Yasmin is one of the major intersections in Bogor City which connected
the two main road, K.H. Sholeh Iskandar road and K.H. Abdullah bin Nuh road. During the rainy
season, this intersection is inundated due to run off from Johar’s street and caused the defective
of main road construction. As a result, the traffic on this road is jam. Since the drainage system
in Johar’s street is failed to accommodate the run off volume, it should be a retention pond to
reserve the rain water to reduce the run off volume which located near the end of Johar’s Street
drainage system. Gumbel-Mononobe’s method is applied to calculate the maximum precipitation
intensity for two year return period and from the analysis the value is 65.20 mm/day or 75.88
mm/hour for time duration 10 minutes. With catchment area is 0.3 hectare, inlet discharge for
retention pond is 0.07 m3/sec, and retain the run off pond volume should be 41,225 m3. This pond
will retain rain water for 163.6 hours or equal to 6.82 days. For slope stability, pond construction
use cobble stone retaining wall with 5 m high and 2.45 m base wide.