松花江流域河流湿地横向连通性分析

Analysis of the horizontal connectivity between the river and wetland in Songhuajiang River Basin

河湖水系连通性包括纵向连通性、横向连通性和垂向连通性。横向连通性指在河流与河岸带、湖泊、湿地之间的通道连通程度。松花江流域中下游区域地势相对平坦,主要湿地类型为河流洪泛湿地,多分布于河流两岸的河滩地上。为了防洪而修建的堤防,阻断了河流与湿地之间的水流联系。选取嫩江尼尔基以下江段和松花江干流为研究对象,采用横向连通性指数法研究河流和洪泛湿地之间的纵向连通性。整个评价范围内河流湿地横向连通性为差,其中,嫩江段(尼尔基以下至三岔河口段)横向连通性等级为中,而松花江干流段横向连通性等级为劣。现状河流洪泛湿地多分布于堤外河滩地内,而堤内的湿地由于堤防的阻隔面积减少较多,堤内湿地与河流之间横向连通性较差;扎龙、向海、莫莫格等重要湿地建设有补水工程,河湖与湿地的连通性较好,而乌裕尔河沼泽湿地没有补水工程,河流与湿地的连通性较差。河湖连通工程的建设十分必要。

Connectivity of river system contains lateral,horizontal and vertical connectivity.horizontal Connectivity denotes the extension of connectivity between the rivers and other targets,such as,river bank,lark and wetland.The middle-lower regions of Songhua River have relatively flat terrene,and their wetlands are mostly created by flooding,which locate at beach of both side river bank.The embankments aiming to preventing flooding cut the relationship between the rivers and wetland.In this paper,we choose downriver of Nen River-Nierji and main stream of Songhua River as targets,and research the lateral connectivity between rivers and wetlands of blooding by method of horizontal connectivity index.The lateral connectivity of river wetlands in the evaluation area is poor,among which the horizontal connectivity grade of Nenjiang section(from Neilji to Sancha estuary)is middle,while that of Songhua river is inferior.The results show that wetlands of blooding and rivers are mostly beam-narrow at outside of bank and inside of beach,and the horizontal connectivity between the rivers and wetlands of river corridor is relatively poor,and the connectivity in Zhalong,Xianghai and Momoge are relatively well because of the supplement-water project,and the connectivity in Wuruer wetlands are relative poor without the supplement-water project.Therefore,the building of connection between river and lake is quite necessary.