Effects of Water Recharge on Ecosystem Health in Baiyangdian Lake, China

Water recharge has uncertainties in health state improvement for medium-sized lake though it possesses the advantage of quick response in nutrient deduction with low-nutrient water. The observed health states before and after water recharge in seven water areas of Baiyangdian Lake have been compared in order to find out the effects of water recharge on ecosystem health. An index system including phytoplankton biomass, zooplankton biomass, the ratio of macrozooplankton to microzooplankton biomass, trophic state index, eco-exergy and structural eco-exergy has been applied to health state characterization. The results show that Wangjiazhai water area, Nanliuzhuang water area and Zaolinzhuang water area acquire great improvement of ecosystem health following the water recharge. The health states in Duancun water area and Quantou water area have improved to some extent while health states change a little after the water recharge in Shaochedian water area and Caiputai water area. It is concluded that water recharge can realize health state improvement of most water areas in Baiyangdian Lake. The entrance of water recharge is considered as the key factor influencing the effects of water recharge in the medium-sized lake.