Study of Polder System for Flood Control In Kembang Residential Area, Bondowoso Regency, Indonesia

Abstract

The rainy season is a season that is often complained by people in various cities because floods often occur. Especially in the Kembang Residential Area on Bondowoso Regency, when there is rain the drainage is unable to accommodate the existing water discharge so that the water overflows and inundates the road surface and settlements around the road. This can be caused by the high intensity of rain, land use that is not regulated properly. And to overcome these problems it is necessary to conduct water management through flood control dams, a system that is made to deal with the problem of excess water, excess water above the ground can be evaluated with a drainage system. In evaluating this drainage system, first we look for field data such as land use, existing drainage conditions, rainfall data for the past 10 years, then its hydrological analysis which includes maximum rainfall, frequency and distribution of rainfall, planned flood discharge. Then the hydrolysis analysis which includes the basic slope of the channel, geometric elements, and the channel planning itself. From the analysis of the drainage system in the Kembang residential area of Bondowoso Regency it was found that the smallest discharge from the drainage system is located on channel 7C which is 0.049 m 3 / second with square cross section, while the largest discharge is in channel 4A which is 1.984 m 3 / second with trapezoidal cross section. Land use greatly influences flood discharge and land use changes which were previously water catchment areas later became residential areas. Land use also affects the adequacy of drainage. In this study, land uses that influences the flow of drainage channels are residential area and rice fields. The drainage system in the area of the Kembang residential area has unequal flow direction between one channel and another. On average, channels that experience changes in existing dimensions to the dimensions of the new channel experience an increase in width or a water level of 15-25%. With the construction of the polder, it can accommodate water capacity of 617.63 m with a building area of 484 m 2 , and a depth of 1.3 m. Thus the channel in the downstream polder does not need to be widened, because the water that flows into the downstream channel has been controlled by the polder door.