Eco-drainage system planning with SWMM model: a case study of Sawah Liat drainage, Kuranji watershed in Padang City, Indonesia

Abstract

Sawah Liat drainage is one area of drainage that the flow of water discharged into the Kuranji River in Padang City. It is a very vulnerable area to the flooding. Flooding was caused by high rainfall, land-use change, and river flooding. This area does not yet have a drainage network system. This research is to plan a new drainage system using the eco-drainage concept of adding a retention pond in the drainage network system. EPA-SWMM model was used to simulate the planned drainage network model and assisted with Global Mapper and ArcGIS for spatial analysis. Six simulation models are performed by combining two models of the drainage network, two land cover models, and two models of rainfall. The results showed that the drainage network models with retention ponds are more effective against controlling flooding. With simulation using a 5-year rainfall return period, there was no flood. For simulations using rainfall data on March 22, 2016, the depth of flooding could be decreasing from 0.2 m to 0.9 m. The retention pond can reduce the 5-year flood volume of 120,200 m3 or 59% of the total 203,710 m3