生态系统调节水量的价值评估——兴山实例

根据植被类型、坡度和土壤类型，分析了兴山县集水区内不同植被地块调节水量的能力。并且根据水能学的原理，分析了枯水期和洪峰期葛洲坝水电站的发电量与水流量的关系，建立了水流发电模拟模型。在上述分析的基础上，评估了兴山县境内生态系统调节香溪河等河流的水量，改善长江全年来水的均匀度，提高葛洲坝水电站发电效率的经济价值。

THE ASSESSMENT OF THE WATER REGULATION OF ECOSYSTEM ——A CASE STUDY OF XINGSHAN

Ecosystem provides multiple benefits for human being, which can be considered as a type of natural resources. The valuation of natural resources is a key step toward their sustainable use. The major functions of the ecosystem, dominated by forests, are water and soil conservation and flow regulation in the catchments of the upper Yangtze River. This is a kind of indirect use value. The focus of paper is to estimate the ecosystem values relating to this aspect.Xingshan County is situated in the western part of Hubei Province. The Three Gorges Dam will be located to the east of the county. The Shennongjia natural protected area lies to the north. The thick forest covers an area of 94×104ha in the county with a coverage of 43.9 percent. The Xiangxi River and the Liangtai River in Xingshan collect 62 comparatively major streams and form two primary water drainages. Both flow into the Yangtze River. Because the benefit from flow ecosystem regulated cannot realize on the spot usually, the use values of the benefit may be transferred spatially by a certain of “passages”to attain to a place out of catchment that provides some suitable external conditions to realize their use values.In accordance with the transfer of value of biological resources spatially, the method of valuation of process benefit was adopted in the paper.The method emphasized quantitative analysis for the process of value rea lizing and the benefit resulting from the value.According to the types of vegetation, soil and slopes, the Xingshan County was divided into 90 types of polygons by means of GIS. The process of value of ecosystem regulated flow was analyzed and the capacity of flow regulation of polygons was determined. In the dry period (December to next April), the ecosystem can release about 150.04×106m3 of water, which can increase the flow of Yangtze River by about 19.3m3 /sec. In the flood period (July to September),it can intercept and contain about 324.77×106m3 of water, leading to a drop of the flow by about 41.77m3/sec. According to simulation models, the increase of 1m3/sec of flow can result in a power increase of 0.17kW at the Gezhouba Hydroelectric Power Plant in the dry period and the decrease of 1m3/sec of flow can make a power increase of 0.04kW in the flood period. The increment of output of Gezhouba Hydroelectric Power Plant by the ecosystem regulating flow was 38.5×106kW·h/a.By above analysis, it is known that the ultimate effect of the ecosystem regulated flow is the increment of output of a hydroelectric power plant. The value of the ecosystems regulating flow is 8.85×106RMB$/a in Xingshan County.