摘要
【目的】探明不同节水条件下河套灌区水盐动态的长期演化趋势,为河套灌区适宜节水规模及灌排管理提供数据支撑。【方法】以河套灌区为研究对象,综合考虑气象、水文地质、土壤、灌溉、作物等多因素的空间变异性,结合SahysMod分布式模型与GIS软件,基于2007-2012年和2013-2016年的实测数据对模型进行率定及验证,模拟不同情景方案下的水盐动态变化。【结果】在现有灌排条件下,年排水量呈先减小后逐渐稳定的趋势,年排水量平均值为5.31亿m3;灌区中上游耕地土壤盐分轻微减小,下游明显增加;综合考虑灌区节水与下游乌梁素海生态环境需水,灌区未来引水量在现有基础上最多可减少15%,最多可节约6.46亿m^(3)水量;若田间灌溉量维持不变,渠系水利用系数(η)最多可提高17.6%;当总引水量的削减量相同时,田间灌溉量削减方案对提升灌区排盐能力效果较佳。因此,可优先考虑减少田间灌溉量,其次提高η。【结论】在灌区规模节水的同时,需综合考虑下游生态环境需求,结合灌区实际生态补水条件确定最佳用水管理方案。
【Objective】Available water for irrigation in Hetao irrigation district has been reduced consistently over the past decades.Improving its water management to alleviate soil salinity is critical to sustaining crop production in this region.The purpose of this paper is to seek optimal water-saving irrigation schemes for this region by using process-based models.【Method】The semi-distributed hydrological model(SahysMod)is used in our study.We consider spatial variability of numerous factors in the modelling,which include meteorology,hydrogeology,soil,irrigation and crops.The model is then combined with GIS to simulate the spatiotemporal dynamics of soil water and salt under different scenarios.Data measured from 2007 to 2012 and 2013—2016 were used to calibrate and verify the model,respectively.【Result】①In a business as usual scenario,the annual drainage decreases first before gradually stabilizing,with the average annual drainage being 531 million m^(3);salinized lands in the middle and upper reaches of the irrigation district decrease slightly,but increase significantly in the lower reach.②Considering water-saving in the whole irrigation district and ecological demand for water in the downstream and the Wuliangsuhai lake,the total water diversion from the canal head should be reduced by 15%from the current level.This will save up to 646 million m3 of water.③If the current irrigation amount remains unchanged,the water utilization coefficient of the canal can be improved 17.6%at the best.④If the reduction in total water diversion from Yellow River is the same,reducing irrigation amount in the field is the best way to boost salt leaching.In this scenario,reducing irrigation amount should be the priority,followed by improving water utilization coefficient of the canal.【Conclusion】In addition to saving water,considering ecological demand of the downstream for water is also important in optimizing water management in Hetao Irrigation District.
作者
常晓敏
刘思妤
王少丽
管孝艳
陈皓锐
CHANG Xiaomin;LIU Siyu;WANG Shaoli;GUAN Xiaoyan;CHEN Haorui(China Institute of Water Resources and Hydropower Research,Beijing 100038,China;National Center for Efficient Irrigation Engineering and Technology Research-Beijing,Beijing 100048,China)
出处
《灌溉排水学报》
CAS
CSCD
北大核心
2023年第4期81-91,共11页
Journal of Irrigation and Drainage
基金
国家自然科学基金项目(52109073)
青海省基础研究项目(2021-ZJ-709)。
关键词
SahysMod
水盐动态
空间变化
灌区节水
灌排管理
SahysMod model
water and salt dynamics
spatial change
irrigation water saving
irrigation and drainage management
