Evaluasi Sistem Saluran Drainase pada Kawasan Jalan Bunga Cempaka Kecamatan Medan Selayang Kota Medan

Abstract

In this research, the focus of evaluation is the condition of the drainage system in the Bunga Cempaka Road area, Medan Selayang Subdistrict. Drainage is a series of water structures designed to reduce and/or dispose of excess water from an area or land, enabling the land to be optimally utilized. The issue is raised due to rainwater inundation occurring in the mentioned road area, especially during heavy rainfall. As a consequence of this problem, an evaluation of the drainage channel capacity is conducted to determine whether it is adequate to handle flood discharge. Data collection in this study includes primary data consisting of the existing drainage system and flow condition data, and secondary data including maximum daily rainfall data from three BMKG rainfall stations and a general map of the study area. The rain gauge station observation points are determined using the Thiessen polygon method, resulting in observation points including the BMKG Helvetia station. The Log Pearson Type III method is employed in this study, and the rainfall intensity is calculated using the Mononobe formula for a 5-year return period, amounting to 112.619 mm/hour. From the evaluation results of the 5-year return period flood discharge using the rational method, Qr1 = 1.748 m3/sec and Qr2 = 1.541 m3/sec are obtained. Calculating the existing channel capacity yields Qs1 = 1.458 m3/sec and Qs2 = 1.255 m3/sec. Comparing the existing channel capacity with the planned discharge, it is evident that the existing channels cannot accommodate the planned flood discharge, leading to water overflow from the channels and flooding the surrounding area. To address this issue, a redesign of the drainage channel is proposed.