Perencanaan Saluran Drainase dalam Pengendalian Banjir pada Kawasan Industri PT. DDD Menggunakan Optimasi Linear Programming

Abstract

Increasing rainfall intensity in industrial areas can cause waterlogging, disrupt operations, hinder the mobility of vehicles and heavy equipment, and potentially damage company assets. This study aims to determine the 10-year return-period design flood discharge, evaluate the capacity of the existing drainage channel, and determine the optimal outlet dimensions in the Central Workshop area of PT. DDD, Gresik Regency. Based on field observations, the study area has a catchment area of 300 m² and is predominantly covered by impermeable concrete pavement, resulting in local waterlogging totaling approximately 6 m³. Hydrological analysis was conducted using the Log-Pearson Type III Distribution validated by the Chi-Square test, while rainfall intensity was calculated using the Mononobe Equation and the design flood discharge was determined using the Rational Method. The analysis results indicate that the 10-year return period design rainfall of 336.29 mm produces a design flood discharge of 0.04587 m³/s. Hydraulic capacity evaluation indicates that the existing drainage channel has a capacity of only 0.025 m³/s, which is insufficient to adequately convey the design flood discharge and may contribute to waterlogging. To address this problem, three PVC outlet pipe alternatives with diameters of 100 mm, 150 mm, and 200 mm were evaluated. The optimization results using Linear Programming indicate that the 200 mm-diameter PVC pipe is the optimal alternative because it offers the highest flow capacity and the shortest waterlogging recession time. Therefore, installing a 200 mm-diameter PVC outlet pipe can serve as an alternative solution to controlling waterlogging in the Central Workshop area of PT. DDD, supported by regular drainage system maintenance to maintain optimal hydraulic performance