Different Land Use Types Of Non-point Source Pollution On Nitrogen And Phosphorus

This paper dicusses the impact of different land-use types on the non-point source nitrigen and phosphorus pollution in Guangfuhe watershed based on the SWAT2000. The different land-use types influence the load capacity of N, P through influencing the runoff, sedment. According to the actual monitoring data, this paper corrects and confirms the model to improve the adaptability of the model and the accuracy of the imitated result. It works out the best way to use the land to control the non-point source nitrogen and phosphorus pollution through the establishing different land use scenarios and comparing the contribution rate of the different land-use types and combined with the actual land policy.This paper includes:(1)The establishment and operation of the SWAT Model. Pre-processing of remote sensing images of the1999and2010using ERDAS9.2. Combined with the requirements of SWAT Model, this paper reclassifies the land-use types and devides the land-use types into7types:farmland, forest, orchard, grass, water and unused land. It establishs the interpreting signs to interpret the two romote images and the spatial database by combing the DEM, the map of land-use, the map of the siol, the map of the water system of Guabg River,the map of the administration and the map of the hydrological and meteorological stations in the watershed. It calculates physical properties datas of the soil by querying The record of the soil in Shandong and using SPAW and MATLAB7.0and the related foemulas. The chemical properties datas of the soil uses the default value of the model in order to establish the properties of the SWAT model database. Organizing and storing the different meteorological datas, such as the recipitation, the temperature, the solar radiation, the wind speed, the relative humidity, according to different stations in order to establish the weather generator to accomplish the meteorological database. (2) The calibration and validation of the model. Calibrating and validation the annual volume of runoff, annual load of sediment and the monthly load of nitrogen and phosphorus according to the hydrological monitoring datas of Huangzhuang hydrological stations to make the Re, R2, Ens to meet the requirements of the model and improve the adaptability of the model and the accuracy of the imitated result. The calibrated SWAT model can be applied to the simulation of the area. According to the simulation results of1987and2010to analyze the trend of the load of the nitrogen and phosphorus.(3) The establishment of different land-use scenarios. This paper sets two groups land-use scenarios according to different purposes.In order to research the impact of different land-use on the hydrological elements and the load of TN and TP, The first group sets five scenarios supposing that the watershed were all farmland, forest, grass and the land-use types of1987and2010used as comparion. In order to discuss the best way of land-use type, the second group stes three groups supposing that the farmland larger than5°should be altered to forest, all the field larger than5°should be altered to forest and all the field larger than5°should bealtered to unused land.This paper draw the conclusion of the impact of different land-use typeds on non-point sources of nitrogen and phosphorus pollution through simulating the load of nitrogen and phosphorus in the different scenarios and comparing the result. And determine the best pattern of land-use type according to the effectiveness of controlling the load of the nitrogen and phosphorus and make the effective measures to control the content of the nitrogen and phosphorus in Guangfu River watershed.