Evaluation of Effectiveness and Efficiency of Green Infrastructure Siting on Existing Water Infrastructure in Urban Area of Jakarta
It is important to analyze flood risks before assigning flood mitigation. Flood mitigations are classified into structural and non-structural approaches. Green infrastructure technologies are among of non-structural flood mitigations. The objective of this research is to evaluate the effectiveness and efficiency of green infrastructure (GI) siting on existing water infrastructure system in Jakarta’s urban spatial detail planning scale of 1:5000. Since this is an ongoing research, this paper proposes the methodology consisting: (1) selection of research site based on typical urban areas, which are, the buildings density, and social and economic factors, (2) flood risk analysis based on hazard and vulnerability mapping, (3) simulation of GI siting using a tool based on Geographic Information System modeling, (4) rainfall runoff analysis, and (5), cost efficiency analysis. The evaluation is carried out in scenarios. The results for this preliminary research are (1) Pasar Rebo sub district is the selected research site, (2) risk mapping that shows the built up lands have the highest risk while vacant lands are the lowest, and (3) rainfall runoff simulation gives the magnitude of peak runoff (Qp) of 334,36 cms and runoff volume (Vr) of 132,03 mm (2.943.255 cubic-meters). The result also shows some vacant lands which are potential for detention ponds located next to the Cijantung River with the total area of 6,3 hectares and 2,75 m depth, that can store 154.350cubic-meters of runoff volume. A preliminary conclusion indicates that the methodology is feasible to proceed in order to achieve the objectives as stated.