Penanganan Banjir Sub-DAS Posindo Kota Balikpapan dengan Optimalisasi Penyediaan Infrastruktur Hijau

Abstract

The Posindo sub-basin, emptying into the Ampal river, is still experiencing flooding even though the city government has normalized and regularly cleans the primary river. Therefore, this flood problem cannot be handled conventionally and generically. This research was conducted to formulate optimal flood management scenarios through a green infrastructure approach as an alternative to specific and sustainable flood management. Two analytical methods were used to overcome the research question: the Gumbel Type I distribution to calculate the return period of rain and HEC-HMS and HEC-RAS modeling software to simulate hydrological and hydraulic conditions. The analysis results showed an overflow discharge above the embankment of 0.38 – 1.64 m3/s along the Posindo sub-basin secondary channel. Simulations and optimizations carried out with five scenarios show that the provision of green open space is crucial in maintaining the level of water absorption in the study area. The combined management strategy by maintaining a minimum green open space of 10%, construction of storage ponds, and increasing the capacity of drainage channels is very effective in reducing the overflow height that occurs.