冀北山区生态恢复下生态输水现状分析——基于东北沟流域的实证

冀北山区作为京津的水源区对于保障下游的水资源安全发挥着重要作用。以京津水源区东北沟流域为例,基于土地利用调查数据、降雨数据和参与式农户调查获得流域生态环境变化和生态输水的现状,对近年来冀北山区生态环境变化以及这种变化对下游输水的影响进行了研究。结果表明:东北沟流域生态建设已取得了一定的成就,经过二十余年的自然封禁,林地占了流域面积的一半以上,近年来发生土壤侵蚀的频率和强度都明显减少了,这方面的变化是有利于为下游生态输水;但降雨量减少,可利用的水资源减少,森林面积增加,植被对降雨和径流的拦截,下游输水能力下降。加之,水源区的居民生态保护意识不强,没有认识到所处区域的重要地位。大量的化肥投入诱发的面源污染不利于该区域为下游的生态输水,而为上游提供生态补偿可协调上下游的利益冲突。

Transporting Clean Water to Downstream under Ecological Rehabilitation Background in Northern Mountainous Area of Hebei Province

The northern mountainous area of Hebei Province as the water source of Beijing and Tianjin plays a vital role in ensuring the safety of downstream water.The focus of the study is on changes in eco-environment in the northern mountainous area of Hebei Province and effects of the change on transporting clean water to downstream.The data comprise land use in 1990 and 2009,precipitation from 1980 to 2009 and household survey in Dongbeigou Watershed where many environmental preservation projects were implemented.The results indicated that there was a huge progress in environmental construction with more than 50% land covered by forest;as the increase of vegetation cover,the intensity and frequency of soil erosion went down.By contrast,the available water resources declined due to the decrease of precipitation.The eco-water consumed by forest increased because of vegetation rehabilitation.In addition,the inhabitants in water source have not strong environmental protection sense and don’t realize the important position of water source.Non-point source pollution induced by high input of amount of chemical fertilizer is harmful to transporting water to downstream.Setting up the ecological compensation scheme is a good way to coordinate the conflicts between water source area and downstream.