Refined Calculation of Pollution Loads in Minor Watersheds Based on Improved Output Coefficient Modeling
Refined calculation of pollution loads in minor watersheds is important for managing and improving the quality of water environments in watersheds.This paper took the primary tributary of Qiongjiang River as the research object.After taking into account the characteristics of minor watersheds which are wide-area,decentralized and stochastic,and combining various disciplines of geographic information as well as statistics,multiscale techniques(administrative and grid)are used in this paper to correct the nonpoint source pollution load in the study area and an improved method of estimating pollution loads in minor watersheds was established,to provide references to fine calculation of pollution loads in minor watersheds.The results of the study show that:(1)the maximum values of COD,NH3-N and TP pollution loads before improvement were 848.95 t/a,136.32 t/a and 19.95 t/a respectively,accounting for 48.10％,70.81％and 52.31％of the total pollution loads of COD,NH3-N and TP in the whole watershed,and the estimated pollution loads were too high.(2)The maximum total pollution loads of grid-scale COD,NH3-N,and TP in the improved study area were 24.44 t/a,2.91 t/a,and 1.18 t/a,respectively,and spatially,the areas with greater pollution loads of COD,NH3-N,and TP were located at the county boundary of the study area,close to the watersheds,and in the concentrated planting areas.(3)TP pollution load intensity was the highest and COD pollution load intensity was the lowest in the study area.COD,NH3-N and TP had similar spatial distribution characteristics of pollution load intensity,which was higher in areas dominated by arable land,and lower in areas dominated by forest land,grassland and construction land.Therefore,the refined calculation model of pollution load in minor watersheds proposed in the study not only can fully reflect the pollution status of minor watersheds,but also provides a basis for the management of water environment quality in the watersheds.
Improved export coefficient modelpollution loadGISmultiple linear regression model
万方数据
维普
