ALLOCATION PLANNING OF RUNOFF CONTROL FACILITY IN URBAN WATERSHED

Rapid urbanization brought changes to the social and hydrologic conditions of urban watersheds. Present urban drainage plan gives rise to a mismatch between design capacity and real discharge resulting frequent localized floods in the urban watershed. This paper proposes a practical scheme to allocate urban flood control facilities among subbasins with different land use and runoff characteristics. First, capacity of each of alternative facilities is calculated by model simulation (Tank Model). Multi-Criteria Analysis (MCA) is applied to evaluate the order of priority of alternatives, quantifying their representative costs, risks and benefits for flood control. This enables to select the adaptable facilities for each drainage basin. Then, the combination of selected facilities are evaluated by MCA using criteria appropriate for a basinwide approach. Two steps achieve an effective scheme useful for preventing floods in urban watershed.