猫跳河流域梯级水库磷的夏季变化特征

调查了我国第一条全流域梯级水电开发的河流——猫跳河中梯级水库对磷的拦截效应。于2007年丰水期7~9月在猫跳河流域采集水库坝前分层水样以及下泄水，分析和测试水样中的总磷和正磷酸盐。结果表明：丰水期猫跳河流域梯级水库内部总磷和可溶性正磷酸盐变化趋势相似，而下泄水的磷含量均大于该水库表层水体的磷含量。在猫跳河流域的梯级水库中，上游水库（红枫湖和百花湖）的磷含量明显高于各下游水库，即猫跳河流域各水库顺水流方向磷含量具有逐渐减少的特征，说明该流域梯级水库开发对于全流域磷具有梯级拦截效应；另一方面，各水库的富营养化指数表明该流域各水库均处于较高的富营养化状态，全流域富营养化状态差别与磷的分布特征相似，表现为顺水流方向减弱的规律。

CHANGE CHARACTERISTICS OF PHOSPHORUS IN CASCADE RESERVOIRS ON MAOTIAO RIVER SYSTEM IN SUMMER

The study investigated the phosphorus retention effects of cascade reservoirs of Maotiao River in summer,which had been entirely exploited by 1960s.In order to find out the rules of phosphorus' retention effects,the water samples in the front of the dams by layers and outflow water of each reservoir were collected in cascade reservoirs in Maotiao River from July to September,2007.The total phosphorus and dissolved PO4 P were analyzed in the laboratory.Results showed that the changes of total phosphorus are similar to dissolved PO4 P in each reservoir,while the concentrations of dissolved PO4 P and total phosphorus in release water were higher than that of their surface water.The concentrations of phosphorus in Hongfeng and Baihua reservoirs were higher than the other reservoirs，the P concentration was gradually reduced from upstream to downstream.Meanwhile,this characteristic was similar to the index of eutrophication.As Maotiao River's concerned,the exploitation of cascade reservoirs do have a certain retention effects on phosphorus.