The Application Of Gis In River Basin Water Pollutant Control Decisions

Over the last decade, with the point source pollution has been control effectively,the non-point source pollution has gradually become the main source which affects the quality of water, due to its randomness, complex mechanism and it is difficult to find the sources of pollutants and track the emissions pathway, so the difficulty of monitoring the pollutant sources and reducing pollutant output is increasing, but the dangers which arising from non-point source pollution can not be ignored, controlling the non-point source pollution effectively has become the major issues which affecting the quality of water bodies.Tianjin Yuqiao reservoir is not only an important regulating reservoir in Luan River to Tianjin Project, but also an important source of domestic water, eutrophication has been discovered in the water body of Yuqiao reservoir, and its water quality has been already developed to heavy eutrophication, and phosphorus pollution has become the main component of eutrophication, so we should strengthen the work of control phosphorus pollution of Yuqiao reservoir.In this article, based on the "3S" technology, selecting SCS runoff curve equation and RULSE soil loss model, simulated the "Source-Sink" landscape pattern and the spatial distribution of phosphorus pollution in the entire watershed under different landscape patterns based on the different spatial and temporal scales. The main achievements are as follows:(1)Making hydrological analysis in whole watershed based on1:50000DEM data, the extracted area of error which compared with the actual area of the whole watershed is-0.02%,the river network distribution which is extracted from the watershed hydrological characteristics is basically consistent with the actual distribution of the rivers.(2)Analysis the change of Yuqiao reservoir watershed landscape pattern by selecting multiple landscape indexes as evaluations on the basis of remote sensing(RS) TM images interpretation over the past decade, the result shows that from1999to2009, the "Source" landscape distribution area ratio has increased26.49%, the "Sink" landscape distribution area ratio has decreased21.78%, the distribution area and patch shape of most of the landscape elements are tend to centralization and regularization under the combined effect of natural and anthropogenic factors; Among the three sub basins of Yuqiao watershed, the "Source" landscape distribution area ratio is the largest which reached to47.95%in Li River watershed, the "Sink" landscape distribution area ratio is the largest which reached to68.54%in Lin River watershed, Li River watershed has a better ecological system environment.(3)Using the software of ArcGIS9.3and utilizing SCS model and RUSLE equation, evaluated dissolved and adsorbed phosphorus pollutant output situation from1999to2009by analyzing the process of rainfall runoff and soil loss mechanism.