武汉城市圈的水源涵养功能重要性评价研究

本文以武汉城市圈为研究对象，分析城市发展对该区域水源涵养功能的影响。文中选取植被、气象、地形、土壤和人为5个因子，分别以植被覆盖度、降水量、蒸发量、坡度、坡长、土壤层厚度和覆盖类型作为水源涵养功能重要性的评价指标，综合采用专家判断矩阵和层次分析法构建其指标体系。利用遥感、GIS等空间分析技术对武汉城市圈水源涵养功能重要性进行评价，并分析影响水源涵养功能的各单因子重要性的动态变化及空间分布格局。结果表明：2000-2009年间，武汉城市圈水源涵养功能呈现先增高后降低的趋势；空间分布格局主要表现为武汉城市圈东北部、东南部低山丘陵地带的水源涵养功能重要性较高；短时间尺度上，人为活动所导致植被覆盖度的变化和覆盖类型的改变是影响水源涵养功能的主要因素。其中，2005-2009年间，人类不合理开发利用土地导致植被覆盖度降低、湖泊湿地减少是武汉城市圈水源涵养功能下降的主要原因。

Assessing the Importance of Water Conservation Function in Wuhan City Circle

In this paper, we analyzed the influence of city development on the regional water conservation func-tion in Wuhan City Circle. Taking the factors of vegetation, meteorology, terrain, soil and man-made into ac-count, we respectively selected vegetation cover, precipitation, evaporation, slope, slope length, soil thickness and coverage types as the assessment indicators of water conservation function importance. Based on a combina-tion of the expert judgment matrix and AHP, the index system was built. Furthermore, we applied RS and GIS spatial analysis technology to analyze the dynamic change and the spatial distribution of each factor importance on the water conservation function, and then comprehensively assessed the function importance. The results showed that the intensity of the water conservation function importance increased first and then decreased from 2000 to 2009 in Wuhan City Circle, the area of the most important water conservation function increased from 9283 to 16 131 km2, but then reduced to 11 258 km2, the area of the general important water conservation func-tion increased dramatically, especially from 2005 to 2009 it grew by 1.1 times. The Northeast of the city circle and in the Southeast of the hilly areas were much more important, and the factor of human activities that caused the changes in vegetation cover and coverage types played an important role on the water conservation function in short time. Recently, lots of unreasonable activities, such as deforestation, grass destruction, and farming around the lake turned out. Because of a significant reduction in water area, forest and grass owning to urban ex-pension, the water conservation function changed. The main reason why the water conservation function de-clined between 2005 and 2009 in Wuhan City Circle was that human being explored land irrationally which di-rectly made a reduction in vegetation cover, and in areas of lakes and wetlands.