Analysis Of Nonpoint Sources Pollution In The Watershed On The Basis Of WARMF Model

Studying and Applying advanced non-point sources (NPS) pollution model in China is not only the need of theoretical study of NPS pollution model, but also the need of the practices of NPS pollution control in China. In this study, a watershed water quality management model from the United States -WARMF was used as a platform in Hangbu-fengle watershed, which is the largest river flows into Chao Lake and is enriched in crop production, and a series of exploring studies were carried out. Results are as follows:(1) On the basis of a detailed analysis on the theory of WARMF model and the characteristics of terrain, soil, land use and land cover of the study area, Hanbu-fengle watershed was delineated into 37 simulation subwatersheds. They were grouped based on their terrain characteristics, which aimed to establish the soil layers' configuration;(2) The difference was studied on between the WARMF model and SWAT model;(3) On the basis of sensitivity analysis, the model was calibrated and verified, using hydrology and water quality monitoring data from 2000 to 2003. Results showed that WARMF model had "warm up" period, the modeling results in this period should not be used to calculate and evaluate model's efficiency. With the exclusive of "warm up" period, the all year relative errors of hydrology, sediment and water quality were less than 20%, 50%, 60% respectively, and all Pearson Coefficients for monthly hydrological data were over 0.8 and all Nash-Sutcliffe Efficiency (E_ns) were over 0.55;(4) To compare the simulation result of WARMF model with AVSWAT2000 model, it showed that: the two models both had a perfect simulation results, but the WARMF model had better effect.(5) The SS and TN were studied as the NPS pollution. The loads of them in the entire watershed and each subwatershed, the load entering into the river or into the lake were analyzed systematically. The following results were gotten: the proportion of the NPS pollution load in the total water pollution load, the composing of the NPS pollution load, the relation of the load of NPS pollution and the type of land use, the changes of the NPS load spatially andtemporally, the ratio of the N fertilizer that entering the river or the lake, and so on..This study could provide assistances to the theoretical study of watershed NPS pollution control and management, as well as the raising of practical management measures for NPS control in the study area and other areas.