WATER SENSITIVE URBAN DESIGN APPROACH BASED ON THE SPONGE CITY CONCEPT FOR RAINWATER CATCHMENT DESIGN CRITERIA. CASE STUDY : ANALYSIS OF INFILTRATION AREAS FEASIBILITY IN WAI MHOROCK, PAPUA.

Abstrak

Wai Mhorock sub-district has problem with changes in land use, which have an impact on changes in infiltration of each land use and can cause inundation and flood problem. Based on Sponge City concept, the Water-Sensitive Urban Design (WSUD) approach is essential to placing open spaces that can function as rainwater catchment and absorption areas. This research used three variables, land structure, land use and land slope. For infiltration testing using a double-ring infiltration at each sample point that had been determined using the purposive sampling method. Horton and Mononobe infiltration analysis methods were used to test the water infiltration rate at sample points. The result of the Horton infiltration test showed variations in the infiltration rate between 12 mm/hour, 84 mm/hour, 360 mm/hour and 384 mm/hour. The Mononobe method finds the maximum rainfall intensity graphic value for ten years. The Mononobe intensity value is 196.51 mm/hour. The infiltration rate test graph and the Mononobe top rainfall intensity graph determine the test result of sample points with a degree of water infiltration. Based on these hydrological constraints and spatial analysis, the study formulates specific design criteria for feasible locations: an open retention basin integrated with green open space (GOS) for expansive areas (Sample B) and an underground water storage tank for limited spaces (Sample C). These localized Water-Sensitive Urban Design approaches serve as a sustainable mitigation strategy against flooding in the Wai Mhorock area.