石羊河流域绿洲城市水土资源利用生态风险评价——以武威市为例

石羊河流域是西北内陆典型缺水区,水土资源是相互制约相互影响的有机整体,其供需状况成为决定该流域社会、经济与环境协调发展的生命主线.以武威市为例,基于各区县1987和2010年土地利用数据以及2003 -2009年石羊河水资源公报基础数据,选取水土资源利用效应相关指数,根据各指标所反映的风险内涵,将计算结果加权或分级组合,独立构建水、土资源利用生态风险评估及对策体系,分析研究各区县水土资源生态风险动态及空间变化,最后依据流域位置对评价结果进行综合等级划分.研究结果表明:(1)研究期内武威市各区县土地利用综合风险指数均有所增加,土地利用格局的变化产生了一定的生态风险；(2)2003 -2009年武威市水资源利用生态风险等级明显增加,不同地区需要结合自身条件,采取相应措施,应对水资源生态风险的变化；(3)武威市各区县水土组合生态风险在空间上表现出一定差异性:中下游地区综合生态风险总体大于上游地区.

Evaluation on soil and water ecological risk of oasis city in Shiyang River basin：a case of Wuwei City

The Shiyang River is a typical basin which is lack of water in northwest arid zone with relative backward social economy and ecological environment security problems in its urbanization development. Besides, oasis is a compound ecosystem which is affected by natural and human factors of arid land. The oasis cities relying on inland river basin are the cluster centers of human production and life where also have the most vulnerable human-environment relationship. Water and soil resources make the most important role of regional society、economy and environment harmonize development and they always interact and restrict each other. To explore the water-soil utilization ecological risk aims to reveal its time-space changes and effect, by taking measures we can allocate resource more rationally in oasis region and make harmonize development between social economy and environment protection. The article takes Wuwei city as the case, based on land use change data in 1987 and 2010,bulletin of water resource from 2003 to 2009 then chooses evaluation index within the composite system of “water-soil resource–ecology –society–economy”, then it constructs the water-soil utilization ecological risk assessment model and analyzes its dynamic and spatial change. The assessment model of land resource integrates coverage landscape index as well as land use index; with the thought of regional shortage risk, the water ecological risk model makes comprehensive evaluation from supply、utilization、maintenance and exploitation. At last, countermeasures referred to risk are put forward in this paper. The conclusions show that the land use composite risk index was increased from 1987 to 2010, land use pattern changes produced ecological risk to some degree; from 2003 to 2009, the level of water ecological risk was raised up significantly, counties should take appropriate measures to control the risk change; the water-soil ecological risk exists spatial otherness within the region: ecological risk of middle and lower area of the Shiyang River basin is higher than that of upstream areas. The water-soil utilization ecological risk evolution process of Wuwei is so complex with all kinds of interactive factors. In order to promote the rational development in oasis city of overall benign, we must overcome resource deficiency, develop water-soil resource rationally and promote environment improvement and recovery by scientific means.