Grey Relational Analysis for Ecological Factors of Wangjiachang Reservoir Located in Lixian City, Hunan Province
澧县王家厂水库生态因子的灰关联分析

Based on the mathematics of space theory, according to the normalization, symplectic symmetry, integrity and accessibility, we calculated and analyzed the relevancy of 13 ecological factors of Wangjiachang Reservior through the grey relational analysis under the condition of manual control, including water transparency, water depth (WD), water temperature (WT), dissolved oxygen (DO), pH, conductivity, ammonia nitrogen (NH4+-N), nitrate nitrogen (NO3--N), total phosphorus (TP), total nitrogen(TN), ratio of TN to TP (TN/TP), zooplankton and phytoplankton. The results showed that to the South River, the relational order from high to low was that TN/TP, TN, NO3--N, NH4+-N, zooplankton, phytoplankton, DO, pH, TP, WT, conductivity, transparency, WD; meanwhile, to the North River, the order was that TN/TP, TN, TP, NO3--N, zooplankton, WT, WD, pH, DO, transparency, phytoplankton, conductivity, NH4+-N. In this study, we can get some information, that the ratio of TN to TP, TN and TP are the dominant in all the factors of reservoir, and the conductivity and water transparency have less influence.