1　Introduction

Hubei Province is known as a province of thousand lakes,which provide important support for the social and economic development of Hubei Province.However,the water environment of those lakes have been polluted seriously during the last decades.

Water quality of lakes were not improved previously just through controlling point source pollution,and river-lake connection project has been an important ecological construction to achieve the goal.However,there were some key issues to be answered before connection projects were constructed,such as the effect of connection project on water quality,new pollutions caused by the connection project,the specific and effective scheme for connection project,etc.,and also these questions need to be answered through researches on connection projects of rivers and lakes.

Chang Lake in Hubei province in the middle of China was chosen as the research object to discuss effects of river-lake connection project on lake water quality,and to research and make more specific and effective schemes of water diversion in the connection project,which can also provide certain support for water environmental management of Chang Lake basin.