山西省永定河流域林草植被生态需水研究

以山西永定河流域及周边17 个气象站点1957—2000 年的气象资料为依据,在GIS支持下,从时空角度定量分析了山西永定河流域林草植被生态需水及其在不同植被类型、流域不同地区及植被生长期内的分配。研究结果表明: 山西永定河流域植被建设最小生态需水量为1 628.5×10⁶ m³,对应的盈余水量为653.5×10⁶ m³,适宜生态需水量为2 709.5×10⁶ m³,对应的生态缺水量为427.5×10⁶ m³;降雨总体上能满足相应面积草、灌、乔植被生长期最小生态需水及草地适宜生态需水,基本满足灌木植被的适宜生态需水,不能满足乔木植被适宜生态需水;生态缺水较多的区域主要是大同、怀仁和左云等地,缺水时段集中在4—6 月。关键词:生态需水;林草植被;GIS;山西永定河流域

Vegetation’s Ecological Water Requirement in Yongding River Watershed in Shanxi Province

The Yongding River is one of the seven major river systems in Haihe Watershed and an important branch of the Guanting Reservoir. Since the 1980s, along with the increase of population, economic development and city size's expansion in the upper reaches, increasing water consumption of production and living occupied eco-water requirement greatly. This lead to soil erosion and vegetation degradation in the upper reaches, but also accelerated the Guanting Reservoir sedimentation. For further understanding water usage and hydrologic process in this region so that the vegetation eco-water requirement could be met as far as possible and eco-environmental construction in this area be promoted, this paper performed a study on vegetation eco-water requirement in the Yongding River watershed of Shanxi Province, which is located in the upper reaches of the Yongding River. Based on the data from 17 meteorological stations in the Yongding River watershed of Shanxi Province and neighboring area from 1957 to 2000, vegetation's eco-water requirement in the watershed was estimated by applying agricultural theory and using GIS. In addition, its change characteristics of different vegetation types, different administrative districts and growth periods were analyzed as well. Also, eco-water surplus/scarity was analyzed by applying water balance theory and combining eco-water requirement and rainfall. The results showed that: 1)The minimum eco-water requirement in the study area is 1628.5×10⁶ m³, the corresponding surplus is 653.5×10⁶ m³, the suitable eco-water requirement is 2709.5×10⁶ m³ and the corresponding scarcity is 427.5×10⁶ m³. 2) There is no eco-water scarcity for grass, shrub and forest compared with the minimum eco-water requirement; there is eco-water scarcity for forest and shrub in some area compared with suitable eco-water requirement. 3) The areas with relatively serious eco-water scarce problem are mainly located in Datong, Pinglu, Huairen, concentrating in April to June.