干旱区绿洲用水效率模拟及分析——以策勒绿洲为例

Simulation and Analysis of Water Use Efficiency in an Oasis in Arid Area:a Case Study in Cele Oasis

水资源对干旱区绿洲的可持续发展起着至关重要的作用。为实现绿洲中灌溉用水的合理调配,以策勒绿洲为例,利用干旱区平原绿洲耗散型模型模拟了绿洲水循环的具体情况,并以腾发量占净输入量的比例作为灌溉水利用效率指标,研究了渠东和渠西灌溉水利用效率的尺度变化规律。研究结果表明:在研究区水平衡分量中,地块土壤水分输入主要依赖于渠道灌溉水量(约占96.02),抽水灌溉量只占土壤水输入项的0.34;由于回归水重复利用比例较低,用水效率随尺度的提升规律不明显,当地块数从一个变化到4个时渠西和渠东2个区域内用水效率分别提升了1.94和1.11;作物空间差异性对用水效率的尺度效应有削减作用,原因是粮食作物灌溉需水量比果树大,用水效率低。通过定量分析得到的绿洲水均衡结果,验证了水均衡模型在绿洲研究中的可行性,也为绿洲灌溉水高效利用提供了理论依据。

Water resource plays an important role in the sustainable development of oasis in arid area.In order to realize the rational allocation of irrigation water in an oasis,the specific situation of the water cycle in Cele oasis was simulated by using the dissipative model for plain oasis in arid area,and the scale variation law of the irrigation water use efficiency in the east and west of the area was studied by taking the proportion of the evapotranspiration to the net input as the index of the irrigation water use efficiency.The results show that:in the water balance component of the study area,the land soil water input mainly depends on the channel irrigation water(about 96.02%),and the pumping irrigation amount only accounts for 0.34%of the soil water input.Due to the low reuse ratio of the returned water,the law of water use efficiency improvement with the scale is not obvious.When the number of local blocks changes from one to four,the water use efficiency in the west and east of the study area increases by 1.94%and 1.11%,respectively.The spatial difference of crops can reduce the scale effect of water use efficiency because that the irrigation water demand of food crops is larger than that of fruit trees and the water use efficiency is low.In this paper,the water equilibrium results obtained by quantitative analysis verify the feasibility of the water equilibrium model in oasis research,and provide a theoretical basis for the efficient irrigation water use in Cele oasis.