Analysis on Surface Water Quality in Different Woodland Configuration in Miyun Reservior

Miyun Reservoir is the most important potable water resources of Beijing,which has supplied nearly seventy percent of domestic water for Beijing.So the water quality protection of Miyun Reservoir has become an urgent problem to be solved at present.Therefore,we built water conservation forest experimental site in Taishitun Town of Miyun Reservoir,which was divided into ten parts,and each part was configured in different afforestation models.Then runoff plots were constructed.In order to find out the best afforestation mode of hydrologic benefit,the surface water quality condition of each runoff plot was tested,and the experimental data was analyzed by using synthetic index method,fuzzy mathematics method and gray correlation method.The results showed that different afforestation models indeed had different effects on surface water quality.We thought that the experimental site of NO.2 had the best effect on water quality which was planted with Pinus tabulaeformis and Cotinus coggygria.And its result had achieved the national gradeⅠ.However the other experimental sites had the worse effect than experimental site of NO.2.All the above,we can see that Pinus tabulaeformis mixed Cotinus coggygria was the best afforestation model.And the two species survival rates were more than ninety percent,and were advised for demonstration and extension.