A Study On Evaluation Of Forese Hydro-effect In Maor Mountain Area Based On 3S Techniques

ABSTRACT Using multi-regression, forest hydro-effect measurement model was established in this paper, selecting runoff of 16 temporary hydrometric stations of Ashihe river measured in 1997 as dependent variable and such factors as rainfall, rainfall intensity, gradient, closure, forest stock per hectare and non-capillary porosity of forest soil as independent variables. TM images (including 2.. 3.. 4~. 5 band) were processed by ERDAS in which geometric correction, ratio enhancement and band combination were used. Thematic maps such as vegetation distribution map, soil distribution map and terrain map were produced after input into ArcView by the interpretation of TM image with the field investigation data of this area. The rainfall and rainfall intensity distribution maps were formed based on the Thiessen polygon analysis of 16 hydrometric stations in Arcview3.1. According to the watershed forest hydro-effect measurement model, the evaluation result of forest hydro-effect was measured quantitatively by the overlapping analysis of vegetate map, soil map, terrain map and maps of meteorological factors. The result showed that forest in this area can control the runoff effectively during the growth period (May ~Oct.) and the benefit of decreasing flood was obvious. In this paper, the method for quantitatively analyzing and evaluating forest hydro-effect based on 3S techniques was explored theoretically, which will provide scientific basis for suitable management of forest resources and reasonable planning of land use.