黄土丘陵沟壑区生态环境建设中的水问题——以延河流域为例

水在生态环境建设中具有重要的地位,同时生态环境建设也对水文情势产生重要影响,两者密切相关.黄土丘陵沟壑区属于资源性缺水地区,水土流失非常严重,同时这一地区也是生态环境建设特别是植被恢复与重建的重点区域,研究这一地区的水与生态环境建设间的相互关系具有更加重要的意义.根据黄土丘陵沟壑区的典型流域--延河流域的社会经济统计数据、水文站监测数据及土壤水分和植被生长的有关研究,综合分析后认为:①人口快速增长和社会经济高速发展需要更多的水资源支持,生态环境建设用水受到直接威胁;②生态环境建设特别是建成植被减少了河川径流,由于植被蒸腾过度消耗土壤水库中的水分,一些地方出现土壤干层;③水资源的不足不仅限制了进一步的植树种草,而且也对建成植被产生了不利影响,一些地方甚至出现了"小老树",从而使植被的生态环境效益受到影响.在此基础上,通过分析生态环境建设与水的关系,提出了黄土丘陵沟壑区水资源可持续利用、生态环境可持续建设和社会经济可持续发展的建议.

Research on the Relationship Between Water and Eco-environment Construction in Loess Hilly and Gully Regions

Water is an important factor for eco-environmental construction. Eco-environmental construction has a great impact on water. There is a circular correlation between eco-environmental construction and water. Water resource is lack and loss of soil and water is serious in the loess hilly and gully regions. The regions are the main regions of eco-environmental construction, especially of vegetation restoration and rehabilitation. It is important studying the relationship between water and eco-environmental construction in the regions. According to the data in Yanhe River watershed, some conclusion are demonstrated: 1. More water resource was demanded when population was increasing rapidly and economy was developing fleetly. Water for eco-environmental construction was threatened directly. 2. Eco-environmental construction, especially the built vegetation decreased the runoff. The dried soil layers have appeared in some places. 3. Shortage of water resource limited the farther tree and grass planting and brought on some negative impacts. Small aged trees have appeared in some places. The eco-environmental benefits of the built vegetation have been influenced. On the basis of relationship between water and eco-environmental construction, some advice for sustainable use of water resource, sustainable construction of eco-environment and sustainable development of society and economy was given.