黄河流域典型区域目标ET计算及水资源调配方案评估

为了解决在黄河流域基于径流-蒸散发(runoff-evapotranspiration,R-ET)的水资源管理模式中,区域目标蒸散发(evapotranspiration,ET)的合理确定问题,该文先梳理了目标ET的计算步骤,确定了各分项ET的计算方法,建立了目标ET的评估指标体系,通过研究实例进行验证。目标ET具体的计算步骤和方法为:第一步,根据当地的水资源情况制定方案集;第二步,针对不同的分项目标ET,分别采用分布式水文模型、遥感估算模型及用水定额法等方法进行计算;第三步,通过计算各方案的评估指标体系,进行可持续性、公平性和高效性的评估,确定最优方案。以黄河流域鄂尔多斯地区为研究实例,制定了5个计算方案,经过计算方案1为现状用水方案,目标ET值为468.79 mm;方案2为扩大引黄水方案,目标ET为450.89 mm;方案3为压采地下水方案,目标ET为432.95 mm;方案4为减少引黄水方案,目标ET为406.11 mm;方案5为节水方案,其目标ET为383.27 mm。通过综合评估可知方案5为最优方案。通过实例验证认为,该方法对于区域目标ET的确定是一种适用的、较准确的方法,也会为下一步黄河流域实施基于R-ET的水资源管理模式提供数据基础和技术支撑。

Calculation of area target evapotranspiration in yellow river basin and evaluation of water resource allocation

Abstract: Aiming at target ET calculation in water resources management model based on R - ET (runoff-evapotranspiration) in Yellow River basin, the paper puts forward calculation method and process. The first step is to formulate scheme set according to water resources in research area. The second step is to calculate the target ET of different sub item using the method such as the distributed hydrologic model, remote sensing estimation model, and the water use quota method. The third step is to evaluate each scheme based on the principle of sustainability, fairness and effectiveness, and to find the best scheme. Ordos is taken as the case study and five schemes were calculated in this paper. Scheme 1 is present situation of water resources utilization, and the target ET is 468.79 mm. Scheme 2 is increasing diverting water from the Yellow River, and the target ET is 450.89 mm. Scheme 3 is decreasing the ground water, and the target ET is 432.95 mm. Scheme 4 is to reduce diverting water from the Yellow River, and the target ET is 406.11 mm. Scheme 5 is a saving water plan, the target ET is 383.27 mm. Then, the scheme 5 is the optimal solutions and recommendations according to comprehensive evaluation. The comparison between Scheme 1 and 5 showed that, with the development of population, economy and society, target ET reduced gradually with the high water-saving measures. The proportion of target ET in cultivated land declined, because water consumption of cultivated land reduced. The proportion of residential and industrial land target ET increased due to the economic development. The second and third industry water demand and ecological water use will increase at the same time. In order to guarantee reliability and accuracy of the area target ET, calculation results of distributed hydrological model and the remote sensing estimation method verified the validity. Two methods calculation error of the area actual ET value is 0.78% and 1.22%, respectively. Target ET determination and evaluation in this study provide references for the next step to implement R - ET water management in the Yellow River basin.