Study on Temporal and Spatial Distribution of Runoff and Pollutant yield by Precipitation in Plain Drainage Area

This paper sets up precipitation runoff and pollutant yield models in plain drainnage area to translate temporal and spatial distribution of rainfall, infiltration and evaporation into temporal and spatial distribution of net rainfall within the drainage. Given flow throughput and polygonal feature of river channel that leads to realization of runoff spatial distribution, it adopts Virtual Flow Confluence Yield concept to conduct study on the temporal distribution of runoff yield and flow confluence in plain drainage area and trufully reflect their characteristics. It also sets up pollutional load models based on underlying surface distribution to transform economic and social factors into temporal and distribution of pollutional load in the drainage. It designates the distance from trellis to peripheral river channel and sectional area of river channel as weight to realize automatic allocation of pollutional load migrating volume to peripheral river channel in the context of different land uses, and adopts Virtual Corelation technique to find the solution to temporal process of pollutant runoff yield. It computes and analyzes the patterns of temporal and spatial distrubtiion of runoff and pollution yield of typical plain drainage area in South Jiangsu of Taihu Lake Basin and has verified model accurracy by using water flow and quality coupling model for plain drainage.