Study Of Non-Point Source Pollution In The Heyuan Section Of Dongjiang River Watershed

Dongjiang river watrtshed is Pearl River Delta region of Hong Kong residents and production, the main source of domestic water, as Heyuan Dongjiang River East River section upstream of the main catchment area, its importance is self-evident. In recent years with the development of the region, segment Heyuan Dongjiang River water eutrophication phenomena frequently. The Heyuan multilevel hilly farmland and regional characteristics caused soil erosion, soil erosion is becoming more serious. Non-point source pollution has become the main source of Dongjiang River Heyuan segment. Therefore, the study of non-point source pollution load of nitrogen and phosphorus in Heyuan section of Dongjiang River water will not only contribute to environmental pollution in the Pearl River Basin, but also to the sustainable development of Guangdong and Hong Kong’s social, economic and environmental importance of the generation.This study established the first paragraph Heyuan weather, topography, land use, soil type, agricultural population, the amount of livestock and other East River Valley spatial and attribute database environment. Then through the use of SWAT hydrological model, land use Heyuan Dongjiang River section of the research unit, the establishment of different land use dissolved nitrogen and phosphorus non-point source pollution load model and rural settlements dissolved nitrogen and phosphorus non-point source pollution load segment Heyuan Dongjiang River Basin model; and then with the universal soil loss equation--RUSLE equation, combined with spatial and attribute data, the establishment of a paragraph Heyuan Dongjiang River adsorbed nitrogen and phosphorus non-point source pollution load model; to construct segments Heyuan Dongjiang River Basin non-point sources of nitrogen and phosphorus pollution load models. Final segment using Heyuan East River Valley spatial and attribute database and GIS environment of space technology, Heyuan Dongjiang River section 2014 of non-point sources of nitrogen and phosphorus pollution load was simulated and verified. Heyuan segment and non-point sources of nitrogen and phosphorus load in the temporal and spatial distribution and contribution of different sources of pollution were analyzed. Further to paragraph Heyuan Dongjiang River Water Environment Protection made specific recommendations. The main conclusions are as follows:(1) Heyuan Dongjiang River Basin segment dissolved nitrogen and phosphorus pollutants and hydrological processes are closely related. 2014 dissolved non-point source nitrogen pollution load 23536.46 t, dissolved phosphorus non-point source pollution load 633.91 t. Among them, the dissolved nitrogen non-point source pollution load contribution of different land use and rural settlements respectively 90.95% and 9.05%; dissolved phosphorus non-point source pollution load contribution of different land use and rural settlements was 83.21%, respectively and 16.79%, different land use dissolved nitrogen and phosphorus non-point source pollution load larger proportion.(2) Heyuan segment adsorbed non-point source pollution load of nitrogen and phosphorus in Dongjiang River Basin mainly soil erosion and sediment yield, whereas the amount of rainfall and soil erosion and sediment yield watershed, soil, land use and vegetation cover and a series of factors are closely related. Heyuan Dongjiang River Basin segment sediment yield of about 2.1535 million t, with erosion modulus of about 458.58 t /(km2?a), the total amount of soil erosion was 5.5218 million t in 2014. Adsorbed non-point source nitrogen pollution load 2533.19 t, adsorbed non-point source phosphorus pollution load 904.71 t in 2014.(3) Heyuan Dongjiang River segment non-point source pollution load of nitrogen and phosphorus from the dissolved nitrogen and phosphorus pollution load and absorbed nitrogen and phosphorus pollution load components. 2014 Heyuan Dongjiang River Basin segment non-point source pollution load of nitrogen 26069.65 t, which dissolved nitrogen pollution load accounts for about 90%; non-point source phosphorus pollution load 1538.62 t, which Adsorbed Phosphorus Pollution Load accounted for about 58.8%.