基于DEA的黑河中游灌区水资源配置效率时空分异

绿洲农业用水效率的提高是协调干旱区经济发展与生态建设的关键。以黑河中游农业绿洲24个灌区为研究对象，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，基于数据包络分析（DEA）研究了灌区农业水资源配置效率的时空分异，以及各灌区影响水资源配置效率的主要因素。结果表明:（1）各灌区水资源配置效率存在明显的时空差异。平川、罗城、大堵麻、盈科、板桥、蓼泉、梨园河、六坝等灌区水资源配置效率较高，而马营河、老军、洪水河、童子坝河、西浚、上三、安阳、鸭暖、新坝等灌区水资源配置效率较低。各灌区水资源配置效率均值从2008年的0.797提高到2012年的0.848，空间差异进一步缩小；（2）各灌区水资源配置要素普遍投入过大，水利设施建设及引水密度均超过了灌区实际需求，尤其是山丹县和民乐县的引水密度过大，甘州和高台部分灌区则表现为干渠密度、支斗渠密度明显超过实际需求；（3）DEA最优解显示，灌渠密度普遍饱和，部分灌区引水密度过大，大部分灌区引水密度与投入产出效率最高之间存在34.8%的下调空间。因此，合理分配有限的水资源、大力推广节水工程及措施，是提高绿洲水资源利用效率的主要途径。

Spatiotemporal Differentiation of Water Allocation Efficiency in Oasis Irrigated Areas in the Middle Reaches of the Heihe River

The improvement of water use efficiency on oasis agriculture is the key process in coordination economic development and ecological construction in the arid zones. We focused on the 24 oasis irrigated areas in the middle reaches of the Heihe River. Based on the basic geographic information data, the land cover data and statistic data in oasis irrigated areas, we analyze the spatiotemporal differentiation of water allocation efficiency in the oasis agriculture, and probes into the main factors limiting the water allocation efficiency in each oasis irrigated area. The main conclusions are as follows: (1) The water allocation efficiency in each oasis irrigated area has significant spatiotemporal differentiation. The water allocation efficiency in Pingchuan, Luocheng, Daduma, Yingke, Banqiao, Liaoquan, Liyuanhe, Liuba, etc., is relatively higher; but in the irrigated areas such as Mayinghe, Laojun, Hongshuihe, Tongzibahe, Xijun, Shangsan, Anyang, Ya’nuan, Xinba, it is relatively lower. Water allocation efficiency increases from 0.797 in 2008 to 0.848 in 2012, spatial differentiation has narrowed. (2) Too many water allocation elements have been put into the oasis irrigated area universally, water conservancy facilities and water diversion density exceed the actual demand in irrigated areas; specifically, in the Shandan County and the Minle County, water diversion density is oversize, but in the Ganzhou County and Gaotai County, main canal density and branch and lateral canal density obviously exceed the demand. (3) The optimal solution of DEA shows that irrigation channel density is universally saturated in a part of irrigated areas, water diversion density is oversize, in the most areas, it should be reduced by 34.8% comparing with the best input-output efficiency. Therefore, allocating limited water resources in the irrigated areas reasonably, popularizing water saving projects and measures industriously are the main methods to improve oasis water use efficiency.