地下水超采区目标ET确定——以介休市为例

以介休市为例阐述了地下水超采区目标蒸散发(ET)计算的理论与方法,将地下水位恢复纳入目标ET计算当中,采用先综合、再分项、后评估的方法,计算得到介休市2020年不同水文年的目标ET,即平水年(保证率为50%)、枯水年(保证率为75%)分别为480.9和433.0mm.从区域整体水资源消耗角度出发:根据不同外调水量及地下水开采量组合的水资源条件组合,设置了9种方案,分别计算了各种方案的综合ET;根据不同的农业灌溉节水措施和中水回用措施,提出相应的分项ET方案;根据ET的确定原则,对二者计算结果进行了协调分析与评估,给出了推荐方案,得到目标ET. 

Target ET computing of groundwater over-exploited area: the case of Jiexiu

Traditional water resources allocation theory of "to increase income and to reduce expenditure" ignores water resources cycles,transformation and consumption,therefore does not satisfy the needs of society.Allocation of water resources based on target evapotranspiration (water consumption during regional sustainable development) can proceed from regional hydrologic cycle,to determine regional water balance,to ascertain available amount of regional water resources,and to control water loss of at its roots.In the present work we applied the basic theory and method of target ET computing to over-pumping groundwater area of Jiexiu.Groundwater recovery was included in target ET calculations.Comprehensive,itemizing and post evaluations were used to calculate target ET of Jiexiu in 2020,which were found to be 480.9 mm in normal flow years and 433.0 mm in low flow years.Total regional water resources consumption,together with different combinations of water resources conditions and water transfer volume and groundwater exploitation were applied to nine computational schemes to compute comprehensive ET.Different water saving methods for agriculture irrigation and reclaimed water reuse measures were proposed for corresponding itemized ET schemes.Coordination analysis and calculation evaluation then gave rise to recommendated scheme and target ET.