SWAT Model Apply To Control Non-point Source Pollution In Zhaowang River Basin

This paper showed that chemical oxygen demand, total nitrogen, totalphosphorus and ammonia nitrogen were primary pollutants of Dongchang Lake basedon principal component analysis. On the basis of this result, analysis of the mainindex water quality and quantity of the Dongchang Lake, Canal and Tanzhuangreservoir in previous years found that replenishment water from Canal and Tanzhuangreservoir will not affect the Dongchang Lake in a certain range of water quality.Water quality analysis of Zhaowang River forecasted that it would cause seriouspollution of the Dongchang Lake replenish water from it, although organic oxygenconsumption of Zhaowang River was similar to Dongchang Lake, and the content wasrelatively low, but total phosphorus, ammonia nitrogen and total nitrogen were farbeyond Dongchang Lake, pollution is serious, so it would cause serious impact ofDongchang Lake replenish water from it.Investigation and calculation determined that65.47tons of chemical oxygendemand,13.09tons of ammonia nitrogen,46.96tons of total nitrogen and is7.90tonsof total phosphorus caused by fertilization in Zhaowang River Basin get into the riverin2009.Autochthonic database of SWAT model was built as Zhao Wanghe river basin ofliaocheng city in shandong province was selected as the study area, and actual rainfallevents was simulatied to testify the applicability of the SWAT model in the basin;Finally nitrogen and phosphorus pollution load was simulated after SWAT model wascalibrated, and effect of best management measures to pollution reduction wasevaluated, the results showed that:After calibration of runoff,the Nash-Suttcliffevalue (Ens) was0.73and variance (R2) was0.71in simulation, and also the Nash-Suttcliffe value (Ens) was0.69and variance (R2) was0.84made the simulatedvalues has the very good fitting with the measured values in validation. The waterquality calibration also reached the applicability of standard even though the effectwas not god as the flow calibration. Analysis of the simulation results shows theapplicability that SWAT model could be used in Zhaowang river basin eventhough itwas not good enough to be used in low water seasons.The wheat-maize rotation mode was chosen and chemical fertilization, irrigationtime and measure was designed unified to put into SWAT model combined withinvestigation and analysis of the Zhaowang River and the surrounding area and thelocal reality. Analysis water quality simulated by SWAT model and the amount changeof fertilizer showed that put±20%more to the normal amount of chemical fertilizer,changes of ammonia nitrogen annual average loads were+11%and-7%, totalnitrogen+13%and-9%,and total phosphorus were+9%and-6%.Reduction of agricultural chemical fertilizer appropriately as the high level offertilizer in Zhaowang River Basin can improve water quality of Zhaowang River, butas some water quality index were several times beyond the national water qualitystandards and Dongchang Lake, Reduction of agricultural chemical fertilizer was notenough to achieve the target that Dongchang Lake can replenishment water fromZhaowang River that was up to scratch, improvement of all other parts of the wholeecological system was also essential.