水位变动下的消落带湿地生态工程——以三峡水库白夹溪为例

Ecological Engineering of Drawdown Wetlands Based on Water-level Fluctuation-Baijia Stream in the Three Gorges Reservoir as a Case Study

三峡水库蓄水后形成的消落带,其生态环境既是严峻考验,也是生态机遇。大面积消落带植被在出露的生长季节所蓄积的碳及营养物质是非常宝贵的资源,如果能加以妥善利用,就可化害为利。针对三峡水库消落带现状及存在的问题,必须着眼于消落带的生态友好型利用。立足消落带向增加碳汇、生物生产、环境净化等多功能生态经济效益转变的需求,探索消落带资源可持续利用的生态工程模式。自2008年以来,在三峡库区澎溪河一级支流白夹溪消落带实施了包括基塘工程、林泽工程、鸟类生境再造等生态工程。本文论述了针对水位变动的消落带湿地生态工程设计原则、工程实施内容,简要分析了生态工程的效益。论文最后指出,三峡水库消落带湿地生态工程的未来努力方向是将基塘工程、林泽工程、生境再造工程与生态经济结合起来,开发消落带生态友好型利用的综合集成模式。

The Three Gorges Reservoir （TGR） provides the benefits of flood control, electricity generation and improved transporlation along the river corridor. For the purpose of flood control, the reservoir height varies between 145 m and 175 m above sea level, ereating a reservoir littoral zone of about 350 km2 in total area distribuled along more than 1200 km of shoreline. Most of the littoral zone is flooded dnring October to May and relatively dry during the remainder of the year. Water level regulation has caused marked ecological changes in the littoral zone of TGR. The littoral zone formed after impounded by TGR not only is the crucible to us, but also the ecological opportunity. The vegetation of large-scale hydro-fluetualion belt is a very valuable resouree, if properly used, can turn harm into advantage. In view of the current stalus and existing problems of the littoral wetland in TGR, we should ficus on utilizing resources of the littoral wetland eeo-friendly. Based on the needs for the littoral wetland transform into the multifuntional ecological eeonomie benefit such as increasing carbon sources, biological production, and environmental purification, we must develop the ecological engineering model of suslainable utilizing the welland resourees of the litloral zone. In view of the environment problems of TGR and its eharaeleristics of waler level flucluation, the ecological engineering focusing on resloration of littoral wethmds have been carried out since 2008. The ecological engineering was mainly conducted at littoral wethands in Baijia stream of Pengxi River of TGR, including dike-pond system, submergenee tolerance wetland-woods and waterfowl habitats reereate projects. The design principle and proeess for the eeologieat engineering of littoral wetlands restoration under the eondition of the periodic water level ehange was described in details in tiffs paper. Eft＇eels of the eeologieal engineering and the benefits to the enviromnents were assessed. In the end of the article we proposed that the eeologieal engineering focus on the restoration of littoral wetlands, also should consider ulilizing resourees of the littoral wetlands coo-friendly.