基于绿洲灌区尺度的生态需水及水资源配置效率研究——黑河中游案例

A Study of Ecological Water Requirement and Efficiency of Water Allocation Based on Oasis Irrigation Area Scale:A Case of Middle Reaches of Heihe River

以黑河中游农业绿洲灌区为研究对象,以基础地理信息数据、土地覆被数据和绿洲灌区统计数据等为数据源,基于Penman-Monteith公式和NDVI数据,研究生态需水量的时空分异,在此基础上,结合实际引水量和单产耗水量,分析绿洲灌区水资源配置的效率,得到以下结果。1)年潜在蒸散量在800~1200 mm/a之间,每年6—8月为峰值。多年平均生态需水量在614~999 mm之间,每年4—8月需求最大,空间上呈现从东南向西北逐渐减少的变化趋势,黑河干流沿岸灌区生态需水量相对较大。2)黑河中游引水以地表水为主,地下水为辅。2008年引水总量最大,引水量较大的灌区主要集中在黑河干流沿岸。3)黑河中游水资源配置总体情况较好,黑河干流周边灌区供需比普遍大于1,山丹县及民乐县灌区供需比小于1。近80%的灌区属于水资源配置高效或相对有效的地区,仅4个灌区水资源配置效率低下,1个灌区引水量严重不足,因此适当调整部分灌区引水量,进一步推广节水理念和技术,是全面提高水资源配置效率的途径。研究结果对提高干旱区水资源配置水平有借鉴意义。

Based on many data sources, such as basic geographic information, land use and cover information and statistic data of irrigation areas, the authors picked agricultural irrigation areas in the middle reaches of Heihe river as a study area and analyzed the spatial-temporal distributions of ecological water requirement with Penman-Monteith equation and NDVI data. Considering the real water diversion and consumption per unit grain yield, the efficiency of water allocation was also analyzed. The results show that the annual potential evapotranspiration is between 800 and 1200 mm and the peak occurs between June and August. Average annual potential evapotrans-piration is between 614 and 999 mm while maximum of demand appears from April to August. Ecological water requirement reduces from southeast to northwest gradually which is relatively larger along the Heihe river. Ground water plays major role in water diversion while underground water is minor. The yield of water diversion is the largest in 2008 and irrigation areas which have more water diversions flock around the Heihe river. Overall, water resource allocation overthere is fair good. Water supply-demand rate around Heihe river is generally greater than 1 while it is opposite in Shandan and Minle. Nearly 80% of the irrigation areas can be considered as efficient or relative efficient regions. There are four irrigation districts are inefficient and only one is short of water diversion. Therefore, adjustment of water diversion in some certain regions with promotion of water saving technology can enhance the efficiency of water allocation roundly. The results provide feasible reference to improve the efficiency of water allocation in arid area.