Research On The Effects Of Forest Ecosystem On Water Quality And Water Quality Evaluation In Jinyun Mountain

This paper combines the Eleventh Five-Year "National Technology Support Project of Chongqing Water District Water Conservation Forest in the northern building technology pilot demonstration (2006BAD03A1802)", according to precipitation and the interaction of time and space of forest ecosystems in order for the first time a comparative analysis and mechanism of the combinationmethod, the water quality in forest ecosystems along the migration path within the changes of a more systematic study of the different vegetation conditions, redistribution of precipitation during the forest precipitation, surface runoff, subsurface flow of water changes the chemical elements,of the forest canopy, litter and soil layer on the water quality. Based on this, four kinds of typical water quality evaluation method were selected to evaluation the surface runoff and interflow in different forest types of Jinyun Mountain, the collected surface runoff, subsurface flow to a comprehensive evaluation of water quality and water quality in Jinyun Mountain, under typical rainfall conditions and the total output of pollutants and.A model was build to predicted the pollutant concentrations and output of pollutants.The result can provide a scientific basis on protecting the water quality of Changjing River, developing integrated control measures, grasping the nutrient cycling of forest ecosystems and forest clean water laws, functions to. The results are as follow:(1) When the rainfall through the canopy layer, PH value of all kinds of forest increased obviously, the concentration of K, Na, Ca, Mg are increased, in which a very significant increase in K. he canopy layer don't show apparent effect of adsorption or leaching on Zn, Cu, Fe, and olittle adsorption on Mn elements. For harmful element,canopy layer don't show apparent effect of adsorption or leaching on Cd, Cr. When the rainfall through the canopy layer, the concentration of Pb increased.(2) When the rainfall through the litter layer, PH value of 1:6 mixed conifer, bamboo forest and shrub forest increase while PH value of pine forest, mixed coniferous and 4:6 2:6 coniferous forest, mixed forest decreased; When the rainfall through the litter layer, K, Na, Mg decline in concentration, Ca has increased greatly; Fe, Zn increased slightly, Cu little amplitude, and Mn in all stand increases and decreases, no clear trend; Cd and Cr through the litter layer did not change significantly after the content, while Pb has significantly decreased, indicating that litter layer have adsorption.effect on Pb(3)When the rainfall through the soil layer, only the pine forest and shrub forest'PH arer higher while the others are lower. Soil layer don't show apparent effect of adsorption or leaching on K, Na, Mg, Ca. Soil layer adsorb Zn, Fe, Mn and Pb, while shows a slight leaching or no effect on Cu, Cd and Cr.(4) Blur-mathematics method, gray correlation method and BP neuarl network method were used to evaluated the output water quality in Jinyun Mountain, contrast the actual situation of Jinyun Mountain,we find that when a variety of water quality parameters are given,BP neuarl network method can educed a more reasonable assessment result which can r reflect the real situation of water quality better.So BP neuarl network method can be used as the first choice. Evaluation results show that when the rainfall in Jinyun Mountain is a typical rainfall, the runoff quality can reach Gradeâ…¡, while the interflow reachâ… it accords with the standard of source water or standard of National Nature Reserve.(5) when the rainfall Jinyun Mountain is a typical rainfall (10-25mm), we predict the output concentration of each single factor are as follows:in the surface runoff COD 15.46 mg/L, TP 0.35 mg/L, Cu 0.13mg/L,Zn 0.13mg/L, F 0.633mg/L, Pb 0.047mg/L, Pd 0.002mg/L, in the interflow DO 18.28 mg/L, TP 0.16 mg/L, Cu 0.09mg/L, Zn 0.06mg/L, F 0.00 mg/L, Pb 0.016mg/L, Cr 0.002mg/L.(6) Based on he observations of runoff of many years in Jinyun Mountain, Forest Resource Inventory data of Jinyun Mountain and GIS database,a prediction model of total output of pollutants under typical rainfall in Jinyun Mountain was established.we predict that when the rainfall is 20mm per day, the output of pollutants in inyun Mountain are as follows:COD 6756.65kg, TP 3995.16 kg, Cu 761.30kg, Zn 1200.59kg, F 6604.46 kg, Pb 255.0kg, Pdl4.38kg, subsurface flow for the COD 16512.70kg, TP 2017.94kg, Cu 1533.45kg, Zn 976.52kg, F 0.00 kg, Pb 256.20kg, Cr31.5kg.