Effectiveness Of Boezem As A Zero Runoff In Blimbing Subdistric, Malang

During the rainy season, inundation often occurs in Blimbing Hamlet, Malang, which caused by inadequate existing drains and lack of utilization in water catchment buildings. Therefore it is necessary to accommodate this condition using zero runoff concept, by utilizing boezem, which is expected there is no inundation at all by flowing flow immediately either seeping into the ground or into an artificial landfill. In Blimbing Hamlet, there is a boezem for serving and accommodating rainwater. For overcoming inundation in this area, maximalizing the boezem is significantly essential. This research is aimed to know the effectiveness of boezem for zero runoff. This assessment was done by hydrology analysis to obtain Q2, and Q5, for boezem planning, inlet outlets gate, and new drainage channels. The evaluation for existing drainage system showed there was inundation in some drainage channels. A boezem area of 836.9 m2 with 1.1 m depth can reduce inundation to 10%. Alternative inundation countermeasures are carried out with the added depth of 3 m, floodgates on inlets and outlets with of 0.5 m width steel gate, and drainage channel inlets and outlets. With the rehabilitation of boezem and other complementary buildings, it can reduce inundation by 30%.