真实节水基本概念分析

Analysis on the Essential Concept of Real Water-Saving

利用世行贷款发展节水灌溉项目以来 ,项目区通过工程、农业和管理节水措施 ,取得显著的节水效果 :一是不仅项目区 ,而且全县渠系水、田间水和灌溉水的有效利用系数大大提高 ,灌溉提取水量大幅度减少 ,与此同时 ,农作物 ET值不断下降 ,预计 2 0 10年 ET值降到当地平均降雨量。二是灌区各部分耗水量发生显著变化 ,有项目以后 ,不仅灌溉提取水量 ,作物 ET大幅度下降 ,而且深层渗漏也显著减少。三是真实节水效果显著 :(1)净开采量大幅度减少 ;(2 )真实 (资源 )节水量不断增加 ;(3)作物ET值不断减少 ,尤其重要的是田间水的有效利用系数不断提高 ,无效蒸发相应减少。四是地下水超采状况显著好转 ,到 2 0 10年项目区可实现地下水的零超采 。

Since the implementation of China Water Covservation Project loaned by World Bank in Guantao county,the significant impact has been achieved through the engineering measures, agricultural measures and management measures in the project area.The first one of these achievements is not only the great improvement of use efficiency for canal system world, field water anl irrigating water,but also the large scope of reduction in irrigation groundwater withdrawn.And meanwhile, the crop ET (evapotranspiration) is continuing going down .It was estimated that the ET would decrease down to as low as local precipitation by 2010 .The second is the significant difference of water consumption in each part of the project area after the project began.That is the large reduction of irrigation groundwater exploitation and crop ET ,and the notably decreasing deep seepage as well.The third is obvious impact of real water-saving ,including the large reduction of net groundwater exploitation, continued increment of real water-saving(in the point of view of resources)and continued reduction of crop ET.The most important is the continued increment of the field water efficiency and corresponding reduction of valid evaporation. The forth is the significant improvement of groundwater over-drawn.It is expected that the groundwater over-drawn will be zero in the project area by 2010 and the extent of groundwater going-down will be much smaller in the whole county.