Identification of potential rainwater harvestingsites using SCS-CN and GIS

Water shortage in mountainous areas is a prevailing problem in Northern China. In this study, the upstream of Qinghe River, a semiarid mountainous area in western Beijing, was investigated and relevant solutions were put forward. The Remote Sensing (Erdas imagine 9.1) and Geographic Information Systems (ArcGIS 10) software were adopted to process data about TM images, soil texture map and Digital Elevation Model (DEM). Soil Conservation Service curve number (SCS-CN) method was used to calculate runoff and establishe constraint site selection criteria based on rainwater harvesting technology and technical code. Afterwards, spatial query and proximity analysis on the spatial thematic data and runoff potential were carried out using the ArcGIS10. The site selection of potential rainwater harvesting projects was completed on the basis of the above-mentioned methods. The results showed that: The sites suitable for the construction of water storage pond was as follows: the area of 4.24 km2, 46 reservoirs, 50 water retaining dams, 53 open wells, and courtyard rainfall collection area 4.95 km2. The results provide a reference for the rational utilization of rainwater resources and projects construction.