达拉特旗井灌条件下农田水利用及地下水动态分析研究

以达拉特旗壕庆河流域为研究对象,通过对该区地下水位和水质的监测及农田水利用状况的调查,摸清地下水的年动态变化规律及水质分布,初步估算该研究区农田灌溉地下水年开采量,从而为本流域的地下水资源评价及合理开发,高效利用提供一定的依据。根据数据分析结果,地下水是从西南流向东北方向,补给黄河南岸引黄灌区。观测期间地下水位年际变化受降雨的影响较大,总体呈上升趋势,变化幅度为0.5～1.5m。pH值超过8.5,呈碱性水,部分区域地下水矿化度为0.5～0.9g/L,可用于农业灌溉,随着地下水流动的方向,水质逐渐变差,下游的盐分浓度最大到2.6g/L,需要合理进行灌溉防止土壤盐碱化。通过遥感图片识别分析计算出该区农田面积为1 398hm2,农业灌溉年开采地下水量为516万m3。     

基于SRTM_DEM的泾河流域特征信息提取研究

流域特征信息的提取对于水文地理信息分析、模拟技术和水文模型建立具有重要意义。基于STRM_DEM数据,在ArcGIS9．3环境下,提取泾河流域坡度、坡向等地形特征,以及河网、流域边界和面积等水文要素,并划分子流域。分析表明,当闽值取5000（40．5km^2）时,生成的流域河网能够较好地反映该地区水系。根据河网分级、低级集水区域生成结果和流域地形特征,可划分为32个子流域,为流域分布式水文模型的构建提供了基础地理信息。SRTM_DEM提取泾河和部分支流流域面积误差均较小,说明提取结果与实际非常接近。结果表明,SRTM_DEM数据和ArcGIS9．3提取流域特征信息方便快捷,具有较高的精度和准确性,应用前景广阔。     

排灌输水隧洞正常水深的简捷算法

为了使标准城门洞形断面正常水深的求解具有简单的显函数计算公式,对标准城门洞形断面正常水深的基本方程进行恒等变形,将水面位于底角圆弧段和顶弧段正常水深的超越方程以及水面位于侧边直线段正常水深的高次方程,变成无量纲化正常水深与已知量综合参数的单变量函数方程.引入准线性函数的概念并将准线性函数作为标准模板,再对正常水深的单变量函数方程应用准线性函数标准模板,在工程常用范围即无量纲化正常水深y∈[0.051,.80]范围内进行优化计算及准线性函数逼近,得到了超越方程和高次方程的替代函数方程,替代函数具有类似于线性函数形式,即正常水深的准线性显函数表达式,并进行误差分析.结果表明,在隧洞底部圆弧段正常水深的最大相对误差小于0.36%,侧边直线段正常水深的最大相对误差小于0.31%,顶弧段正常水深的最大相对误差小于0.39%,说明准线性公式在隧洞有效水深范围内计算的水深准确度较高,可为排灌输水隧洞的断面设计及实现渠道水位控制时确定均匀流水深提供参考.     

A preliminary study of an alternative controlled drainage strategy in surface drainage ditches: Low-grade weirs

This study examined hydrological characteristics of low-grade weirs, an alternative controlled drainage strategy in surface drainage ditches. Chemographs of vegetated and clear scraped (control) replicates of weir vs. non-weir treatments were compared to determine differences in time to peak (T_p) and time to base (T_b). Drainage ditches T_p and T_b were affected by both vegetation and weir presence. The order of treatment efficiency for T_p was observed to be: non-vegetated non-weir < vegetated non-weir < non-vegetated weir < vegetated weir. Furthermore, T_b for each ditch was the reverse relationship from T_p where vegetated weir > non-vegetated weir > vegetated non-weir > non-vegetated non-weir. Low-grade weirs increase chemical retention time (vegetated and clear scraped), the average time a molecule of contaminant remains in the system. Future research in water quality improvement and weir management will yield useful information for non-point source pollutant reduction.     

Modeling subsurface drainage for salt load management in southeastern Australia

Subsurface drainage has been implemented in irrigation areas of South-eastern Australia to control water logging and land salinisation. Subsurface drainage has been identified as a major salt exporter from irrigated areas. The water table management simulation model DRAINMOD-S was evaluated to simulate daily water table depth, drain outflow, and salt loads by using experimental field data from a two year field trial was carried out in the Murrumbidgee Irrigation Area South-eastern Australia to study different options for subsurface drainage system design and management to reduce salt load export. Three subsurface drainage systems were modeled, deep widely spaced pipe drains, shallow closely spaced drains and deep pipe drains that were managed with weirs to prevent flow when the water table fell below 1.2 m. The reliability of the model has been evaluated by comparing observed and simulated values. Good agreement was found between the observed and simulated values. The model confirmed the field observations that shallow drains had the lowest salt load and that by managing deep drains with weirs salt loads could be significantly reduced. This work shows the value of the DRAINMOD-S model in being able to describe various drainage design and management strategies under the semi-arid conditions of South-eastern Australia. The model can now be used to investigate design and management options in detail for different site conditions. This will assist decision makers in providing appropriate subsurface drainage management policies to meet drainage disposal constraints within integrated water resources management planning.     

灌排模式对稻田作物水足迹的影响

设置浅水勤灌(FSI)、浅湿灌溉(WSI)、控制灌溉(CI)和蓄水控灌(RC-CI)4种灌排模式,于2017-2018年进行了桶栽观测试验,利用作物水足迹计算方法量化蓝、绿、灰水足迹,分析灌排模式对水稻水足迹及其组成的影响.结果表明:在不同灌排模式下,水稻作物水足迹、组成及其效率均存在差异.所有处理水足迹的范围为846...     

Spatiotemporal changes in terrestrial water storage in the Beijing-Tianjin Sandstorm Source Region from GRACE satellites

The Sandstorm Source Control Project in and around the Beijing-Tianjin region was one of the most important ecological projects in China. Terrestrial water storage (TWS) has important impacts on the ecological construction, agriculture, industry, and resident’s lives. Based on the Gravity Recovery and Climate Experiment (GRACE) data, meteorological and Moderate Resolution Imaging Spectroradiometer (MODIS) data, etc., this paper analyzed spatiotemporal characteristics of TWS, groundwater storage, and precipitation, and explored the influencing factors of regional TWS combined with land use and land cover (LULC), social and economic data. The most important results were as follows: (1) From 2003 to 2016, TWS in the Beijing-Tianjin Sandstorm Source Region showed a decreasing trend with a rate of 3.14 mm yr⁻¹. (2) The TWS decline was caused mainly by groundwater overexploitation, but not precipitation variation. (3) Spatiotemporal variations of TWS were related to LULC. The area with the most serious decrease of TWS was mainly located in the southwestern part of the region, where farmland percentage and population density were greater. (4) Reducing the percent of farmland and tree planting, and adding the shrub and grass planting, could be a viable choice for the Beijing-Tianjin Sandstorm Source Control Project. These results provide a scientific basis for regional water resource and ecological management.     

集中排水甘蔗地酸性硫酸盐土壤酸化的减缓

Recent research results suggest that acidification of acid sulfate soils may be inhibited in well-drained estuarine floodplains in eastern Australia by the absence of natural creek levees,The lack of natural levees has allowed the inuudation of the land by regular tidal flooding prior to the construction of flood mitigation work.Such physiographical conditions prevent the development of pre-draingae pyrite-derived soil acidifica-tion that possibly occurred at many levee-protected sites in eastern Australian estuarine floodplains during extremely dry spells.Pre-drainage acidification is considered as an important condition for accumulation of soluble Fe and consequently,the creation of favourable environments for catalysed pyrite oxidation.Under current intensively drained onditions,the acid materials produced by ongoing pyrite oxidation can be rapidly removed from soil pore water by lateral leaching and acid buffering,resulting in low concentrations of soluble Fe in the pyritic layer,which could reduce the rate of pyrite oxidation.     

A Framework for Valuing Ecological Services of Irrigation Water – A Case of an Irrigation-Wetland System in Sri Lanka

In many countries, irrigation water is usedfor several purposes other than irrigatingfield crops. In Sri Lanka, irrigationwater from canals, wells, and reservoirs isused for domestic purposes, industry,livestock, and fisheries, and it alsocontributes to sustain the environment. However, policy makers and water managersin irrigation systems only take intoaccount water used for irrigating the fieldcrops and sometimes water used for domesticpurposes. Owing to the failure torecognize the different uses and users ofwater, the water in irrigation systems hasbeen undervalued. This paper presents theenvironmental impact of irrigation and aframework for valuing water for itsmultiple and often competing uses,especially focusing on water uses forecological services, in this case wetlands.The south coastal area of Sri Lanka wasselected as a site for a case study, including2,610 ha of irrigated area and adownstream wetland area of 2,250 ha whichhas five lagoons. This wetland areacombines coastal, marine and freshwaterecosystems in a tropical environment inwhich distinct plant and animal speciescoexist in a delicate balance. All users ofwater and other resources, and theirenvironmental problems were identified. Thispaper discusses the policy and managementimplications of valuing water for competinguses.     

基于模糊模式识别的农田排水再利用适宜性评价

以受盐渍化威胁的干旱半干旱地区为研究对象,基于构建的农田排水再利用适宜性评价指标体系,采用模糊模式识别方法建立了农田排水再利用适宜性评价模型;综合分析相关文献和已有标准,制定出评价指标体系各项指标的分级标准值范围和标准值,采用层次分析法确定各评价指标的权重.以宁夏银北灌区5个典型排水再利用区域为例的评价结果表明,除前进农场外,其他区域评价等级均在2级“适宜”排水再利用范围内.其中灌溉中、后期利用排水灌溉的适宜性级别特征值低于前期,即排水再利用的适宜程度好于前期,该时期正是作物需水量较大和灌溉用水紧张期,处于作物盐分非敏感期,适宜地再利用一定量的农田排水是可行的.