Study of Flood Management Due to Rainfall on Drainage Network System in Residential Area (Case Study: Cempaka Sub District, Banjarbaru City, South Borneo)

Abstract

ABSTRACT : The initial indication of this research was carried out by the occurrence of floods that was correlated with the conditions of the slum settlements in Cempaka Sub District, narrowing and silting of the river, as well as the rainfall that fell beyond the carrying capacity of the river geometry in that area. The goverment is concerned about the inability of existing drainage network system to accommodate and drain the water, causing a flood problem that impact to human settlements. A recommendation was given for the drainage channel design in the form of sodetan using box culvert in an effort to deal with flood problems that every year hit residential area in Cempaka Sub District. The work process is by dividing the planned flood discharge in the existing river channel with a cross sectional capacity of the Kuranji River of 24.912 m 3 /s, which means that there is a runoff of 11.704 m 3 /s. The runoff flood discharge is flowed through sodetan using box culvert with capacity of 13.032 m /s. From the results of the financial feasibility analysis using net present value, benefit cost ratio, and internal rate of return method with an interest rate of 9.90% based on cash flow obtained from the value of losses for flood affected humans that investment in the sodetan development project uses box culvert in the size 1.5 m × 1.5 m is declared feasible and enforceable.