小浪底水库对黄河三角洲湿地水分条件和景观格局的影响

研究了小浪底水库对黄河河口湿地水分条件的影响,并利用遥感方法分析了黄河三角洲湿地景观格局在小浪底运行前后的的变化情况。研究表明:(1)降雨是补给湿地水分的重要因素,由于其时间分布不均,使得黄河三角洲具有生态缺水时段;黄河的侧渗补给与降雨补给时段相同,5—7月的来水量大,补给量大,是第二大淡水补给来源。河流侧向补给的增加水量对河道沿岸附近2.5km范围内湿地的水位具有较大的影响,但对整个湿地水分改善没有明显作用。(2)小浪底水库运行后湿地总面积略有增加,其中天然湿地面积减少90.29km2,人工湿地(主要是盐田)面积增加150.11km2;沿海湿地总体上仍以海水侵蚀为主,但与小浪底运行前相比,黄河现代三角洲的河流湿地面积明显增加,同时盐碱化过程受到遏制。

Influence of Xiaolangdi Reservoir on Moisture Conditions and Landscape Pattern of Yellow River Delta Wetland

The influences of Xiaolangdi reservoir on the replenishment of the Yellow River estuary wetland were analyzed,and the changes before and after the operation of the reservoir on the landscape pattern of Yellow River Delta wetlands were detected using remote sensing.The results show that rainfall was an important source for the wetland replenishment.As the rainfall was unevenly distributed each year in the study area,periods ecologically short of water often occurred.From May to July each year,lateral seepage from the Yellow River and rainfall infiltrations were overlapped,providing large amount of water supply to recharge the wetlands.The water supply of lateral seepage showed great influences in about 2.5km of the riparian buffer,but no obvious effect on the entire wetland.After the operation of the reservoir,the total area of the wetland increased slightly,specifically with areal reduction of 90.29km2 in natural wetland and areal increase of 150.11km2 in artificial wetlands.The coastal wetlands have experienced sea erosion generally.Overall,the area of the wetlands in the study area increased substantially and the salinization process has been restrained after the operation of the reservoir.