The invention provides an
estimation method for load of
watershed agricultural non-
point source pollutants into a lake. The
estimation method includes acquiring data of a typical small
watershed in a target
watershed, creating a SWAT (soil and water assessment tool) of the typical small watershed, and acquiring LoadLr and LoadLo in the typical small watershed according to the SWAT; acquiring planting industry source,
livestock and poultry industry source,
aquaculture industry source and rural life source
pollutant producing and discharging coefficients of each sub watershed of the typical small watershed, and combining basic information survey data to acquire LoadLs in the typical small watershed; acquiring target watershed agricultural non-
point source pollutant ditch reduction factor Factorcr according to the LoadLs and the LoadLr; acquiring LengthLr according to water
system data; acquiring target watershed agricultural non-
point source pollutant riverway
reduction factor Factorrr according to the LoadLr, the LoadLo and the LengthLr; acquiring target watershed agricultural non-point source
nitrogen and
phosphorus discharge load and the total length LengthBr of an inner riverway of the target watershed; acquiring the load of the target watershed agricultural non-point source pollutants into the lake according to the target watershed agricultural non-point source
nitrogen and
phosphorus discharge load, the Factorcr, the Factorrr and the LengthBr. By the method, the total load of the watershed agricultural non-point source pollutants into the lake can be acquired simply, accurately and rapidly, cost is low and large-scale comprehensive implementation is achieved.