景电灌区田间水转化模拟与区域地下水动态响应关系研究

发布时间：2018-11-01 17:35

【摘要】：对于我国西北干旱和半干旱地区,土地资源丰富,光照充足,但是水资源十分贫乏,为解决西北干旱地区水资源缺乏,国家兴建了许多扬水灌区,但随着大量水的调入,引起了如地下水位上升及土壤次生盐碱化等许多生态环境问题。因此,开展干旱扬水灌溉区域的田间水分运动规律及地下水位动态研究对灌区水资源的科学管理和土地资源的可持续开发利用有着重要意义。本文以景电灌区为研究区,采取现场调查的方法收集了灌区的气象、灌溉、作物、土壤及地下水资料,通过Hydrus-1D软件模拟研究田间土壤水分动态规律,利用灌区灌溉试验站得出的土壤含水率对模型进行验证,确定了模拟的合理性和准确性,根据模型模拟结果得到了田间土壤含水率、蒸散发、渗漏及水量平衡变化规律;再通过多年的监测资料得出了区域地下水动态变化,结合M-K检验法和R/S分析法研究了地下水位变化趋势,得出以下结论:(1)根据Hydrus-1D的土壤水分运动模拟结果表明:土壤含水率与土壤深度有关,越深层的土壤含水率越高,在灌溉后各层土壤含水率均会大幅提升,降雨只对50cm及以上土层有影响;一个玉米生育周期内土壤水补给来源为降雨和灌溉,总计953.7mm,土壤水消耗项为蒸散和深层渗漏,总计875.8mm,蒸散量占土壤水总补给量的50.7%,渗漏量占土壤水总补给量的41.1%,土壤水分储量变化为77.9mm,占土壤水总补给量的8.2%。(2)地下水浅埋区土壤表层含水率与深埋区较为一致,底层土壤含水率受灌溉和地下水影响变化较大;由于地下水会补给土壤水,故田间蒸散量会增加,地下水浅埋区的土壤水与地下水存在频繁的相互交换关系,在灌溉时,灌溉水通过入渗作用补给地下水,在无灌溉时,由于土壤蒸发和作物蒸腾导致的毛细作用会引起地下水补给土壤水。(3)经过多年的提水灌溉,景电灌区各处地下水水位均有提升,汇水聚盐带的地下水位上升最明显,20年来提高了13米,并已露出地表;溶质运移带的下水位受汇水聚盐带地下水位抬升的影响,也有所上升;灌溉入渗带和潜水排泄带的地下水位虽然处于波动状态,但因补给量与排泄量相对平衡,所以整体地下水位处于相对稳定的状态。研究结果可作为景电灌区灌溉水优化配置及地下水合理利用等方面的理论依据,对维护灌区生态环境稳定具有重要意义。
[Abstract]:For arid and semi-arid areas in northwest China, land resources are abundant and light is sufficient, but water resources are very poor. In order to solve the shortage of water resources in arid areas of northwest China, the state has built many irrigation areas with raising water, but with the transfer of a large amount of water, It has caused many ecological environmental problems, such as the rise of groundwater level and the secondary salinization of soil. Therefore, it is of great significance for the scientific management of water resources and the sustainable development and utilization of land resources to carry out the research on field water movement and groundwater level dynamics in arid water raising irrigation areas. In this paper, the meteorological, irrigation, crop, soil and groundwater data of the irrigated area were collected by the method of field investigation, and the dynamic laws of soil moisture in the field were simulated by Hydrus-1D software. The model was verified by the soil moisture content obtained from irrigation experimental station in irrigation district, and the rationality and accuracy of the simulation were determined. According to the simulation results, the variation rules of soil moisture content, evapotranspiration, leakage and water balance in the field were obtained. Based on the monitoring data for many years, the regional groundwater dynamic change is obtained, and the trend of groundwater table change is studied by using M-K test method and R / S analysis method. The conclusions are as follows: (1) according to the simulation results of soil moisture movement of Hydrus-1D, the soil moisture content is related to the depth of soil, the deeper the soil moisture content is, the higher the soil moisture content will be after irrigation. Rainfall only affects 50cm and above soil layer. In a maize growing period, the source of soil water supply was rainfall and irrigation, the total amount of soil water consumption was evapotranspiration and deep leakage, the total amount of soil water supply was 875.8 mm, and the evapotranspiration accounted for 50.7 mm of the total soil water supply. The leakage amount accounts for 41.1% of the total recharge of soil water, and the change of soil water reserve is 77.9 mm, accounting for 8.2% of the total amount of soil water supply. (2) the soil surface water content in shallow groundwater area is consistent with that in deep buried area. The water content of the bottom soil is influenced by irrigation and groundwater. Since groundwater recharge soil water, the field evapotranspiration will increase, and there is a frequent exchange relationship between soil water and groundwater in shallow groundwater area. During irrigation, irrigation water recharge groundwater through infiltration, when irrigation is not irrigated, The capillary action caused by soil evaporation and crop transpiration will cause groundwater to recharge soil water. (3) after years of water raising irrigation, the groundwater level in Jingdian irrigation area has been raised, and the groundwater level in the catchment salt belt is the most obvious. It has been raised by 13 metres in 20 years and has been exposed to the surface of the earth; The lower water level of the solute transport belt is affected by the uplift of the groundwater level in the catchment salt belt, and it also increases to some extent. Although the groundwater level in the irrigation infiltration zone and the submersible discharge zone is in a fluctuating state, the whole groundwater table is relatively stable because of the relative balance between the recharge and the discharge. The results can be used as the theoretical basis for optimal allocation of irrigation water and rational utilization of groundwater in Jingdian irrigation area. It is of great significance to maintain the stability of ecological environment in irrigation area.
【学位授予单位】：华北水利水电大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S27;S152.7

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