Spatio-temporal characterization of the Pliocene aquifer conditions in Wadi El-Natrun area, Egypt
Spatio-temporal characterization of the Pliocene aquifer conditions in Wadi El-Natrun area, Egypt
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DOI：
10.1007/s12665-010-0623-2
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发表时间：
2011-04
影响因子：
2.8
通讯作者：
A. Masoud;Mohamed G. Atwia
中科院分区：
文献类型：
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作者：
A. Masoud;Mohamed G. Atwia
Wadi El-Natrun地区最近经历了大规模的城市和农业扩张。由于缺乏天然地表灌溉供应，该地区唯一的水源是上新世地下水含水层。因此，由于抽取量增加而造成的次生盐碱化是对地下水含水层的主要威胁。迫切需要制定有效的战略，以确保该地区农业生产的长期可持续性。这些战略应建立在对地下水状况进行科学的时空监测和分析的基础上，而目前也缺乏这种监测和分析。为了捕捉地下水条件的时空变化，在2006年和2007年期间收集的47个地下水样品进行现场测量的总溶解固体，电导率，pH值，温度和水位以及基于实验室的离子组成。对样品进行了水化学特征、水类型、盐组合和钠吸附率的测定。1973年和1997年记录的参考数据集可用于监测这两个时期发生的变化。对地理信息系统进行了评价，以用于制图和不同层面的综合分析。遥感变化检测技术应用于大地卫星TM和ETM +图像，并用于突出大规模开垦和城市化，并找到地下水条件及其与土地覆盖物的空间关联的变化的主要趋势。结果显示，地形凹陷引起的流型，优势的浸出和溶解过程，盐湖的存在，从上新世含水层过度抽水，土地利用的时间变化是主要因素相结合，以控制地下水的时空变异。结果还澄清了存在两个：西北和东南区，不同的流体动力学和水化学特征。西北区水位平均下降15米，水质微咸（平均水位）。2，037 mg/l），主要为Na+、Cl−和SO 42 −离子。该区域的地下水具有高至非常高的盐度危害和高至非常高的碱危害，不建议用于灌溉排水不良和没有适当管理的土壤。东南区水位下降小于2 m，为淡水区（平均水位）。424 mg/l），主要含有Na+、HCO 3 −、Cl−和SO 42 −离子，质量适合于中高盐度和低至中等碱危害的灌溉。这篇文章代表了在GIS框架内对Wadi El-Natrun地下水资源进行综合管理的第一步。
Wadi El-Natrun area has recently undergone extensive urban and agricultural expansion. Due to the absence of natural surface irrigation supplies, the only source of water in the area is the Pliocene groundwater aquifer. As a result, secondary salinization from increased abstractions is the major threat to the groundwater aquifer. There is a dire need for efficient strategies to ensure long-term sustainability of the area’s productive agriculture. These strategies should be based on scientific spatio-temporal monitoring and analysis of the groundwater conditions that is also lacking. To capture the spatio-temporal variability in groundwater conditions, field measurements of total dissolved solids, electrical conductivity, pH, temperature, and water level as well as lab-based ionic composition were performed on 47 groundwater samples collected during 2006 and 2007. Determinations of the hydrochemical characteristics, water types, salt assemblages, and the sodium adsorption ratio were carried out on the samples. Reference data sets recorded in 1973 and 1997 were available for the area and were used to monitor the changes occurred in these periods. Geographic information system (GIS) was appraised for mapping and for integrated analysis of the different layers. Remotely sensed change detection techniques were applied to the Landsat TM and the ETM + imageries and used to highlight the extensive reclamation and urbanization and to find key trends for the alterations in the groundwater conditions and their spatial association with land covers. Results revealed a topographic depression-induced flow pattern, predominance of leaching and dissolution processes, the presence of saline lakes, over-pumping from the Pliocene aquifer, and temporal changes in land uses are the main factors combined to control the spatio-temporal variability in the groundwater. Results also clarified the presence of two: northwestern and southeastern zones that varied distinctively in their hydrodynamic and hydrochemical characteristics. The northwestern zone showed an average water level decline of 15 m, the water of which is brackish (av. 2,037 mg/l) with dominant Na+, Cl−and SO42−ions. The groundwater of this zone is characterized by high to very high salinity hazard and high to very high alkali hazard and is not recommended for irrigation on soils with poor drainage and without proper management for salinity control. The southeastern zone showed water level decline less than 2 m, the water of which is fresh (av. 424 mg/l) with major Na+, HCO3−, Cl−, and SO42−ions, and quality suitable for irrigation with medium to high salinity and low to medium alkali hazards. The article represents the first step towards an integrated management of Wadi El-Natrun groundwater resources within a GIS framework.