PENGENDALIAN BANJIR MELALUI PERENCANAAN SISTEM POLDER DI RW 39, KELURAHAN BOJONG RAWALUMBU, KOTA BEKASI

Abstract

RW 39, Kelurahan Bojong Rawalumbu kerap mengalami banjir akibat pertemuan dua sungai, kapasitas drainase yang terbatas, topografi datar, dan urbanisasi. Sistem polder menjadi solusi pengendalian banjir di wilayah tersebut. Penelitian ini bertujuan menentukan catchment area, mengolah data curah hujan sebagai input model SWMM, serta merancang kapasitas polder yang efektif dalam meminimalkan risiko banjir. Penelitian ini menggunakan data primer berupa dimensi saluran dan data sekunder berupa data DEMNAS, Peta RBI, dan data curah hujan 10 tahun dari CHIRPS dan BMKG. Catchment area diperoleh sebesar 7,56 ha berdasarkan analisis topografi. Metode distribusi yang sesuai yakni Metode Gumbel dengan PUH 5 tahun, yang menghasilkan intensitas hujan mononobe dengan durasi hujan 24 jam. Pemodelan jaringan drainase menunjukkan dua di antaranya melebihi kapasitas dan dua lainnya tidak sesuai standar sehingga harus diperbaiki. Sistem polder yang dirancang terdiri dari kolam retensi seluas 1.302 m² dengan kedalaman 3,5 m, saluran inlet dan outlet, serta rumah pompa. Air hasil pemompaan dialirkan melalui saluran tertutup baru menggunakan box culvert 0,5 m × 0,5 m. Hasil simulasi menunjukkan sistem polder mampu mengurangi genangan secara efektif.

RW 39, Bojong Rawalumbu Urban Village often experiences flooding due to the confluence of two rivers, limited drainage capacity, flat topography, and urbanization. The polder system is a solution for flood control in the area. This research aims to determine the catchment area, process rainfall data as input for the SWMM model, and design an effective polder capacity in minimizing flood risk. This research uses primary data in the form of channel dimensions and secondary data in the form of DEMNAS data, RBI Map, and 10-year rainfall data from CHIRPS and BMKG. Catchment area was obtained as 7.56 ha based on topographic analysis. The appropriate distribution method is the Gumbel Method with a 5-year PUH, which produces mononobe rainfall intensity with a rainfall duration of 24 hours. Modeling of the drainage network showed that two of them exceeded capacity and two others were not up to standard so they had to be repaired. The designed polder system consists of a 1,302 m² retention pond with a depth of 3.5 m, inlet and outlet channels, and a pump house. The pumped water is channeled through a new closed channel using a 0.5 m × 0.5 m box culvert. The simulation results show that the polder system is able to reduce inundation effectively.