GroMoPo Metadata for Western Nile Delta model

The limited availability of renewable fresh water is a major constraint on future agriculture and urban development in Egypt. The main water resource that Egypt has been depending on is the River Nile. Nowadays, the role of groundwater is steadily increasing and will cover 20% of the total water supply in the coming decades especially in the reclaimed areas along the desert fringes of the Nile Delta and Valley. Abstraction from groundwater in Egypt is dynamic in nature as it grows rapidly with the expansion of irrigation activities, industrialization, and urbanization. One of these areas is the Western Nile Delta in which the groundwater is exploited in many localities. To avoid the deterioration of the aquifer system in this area, an efficient integrated and sustainable management plan for groundwater resources is needed. Efficient integrated and sustainable management of water resources relies on a comprehensive database that represents the characteristics of the aquifer system and modeling tools to achieve the impacts of decision alternatives. In this paper, a GIS-based model has been developed for the aquifer system of the Western Nile Delta. The GIS provides the utilization of analytical tools and visualization capabilities for pre-and post-processing information involved in groundwater modeling for the study area. The developed model was calibrated for steady state and transient conditions against the historical groundwater heads observed during the last 20 yr. The calibrated model was used to evaluate groundwater potentiality and to test two alternative management scenarios for conserving the aquifer system in Western Nile Delta. In the first scenario, reducing the surface water inflow while increasing the annual abstraction from groundwater by about 450 million m(3) and improving the irrigation system could increase the net aquifer recharge by about 5.7% and reduce the aquifer potentiality by about 91%. Constructing a new canal as a second management scenario could increase the annual aquifer potentiality by about 23%. The GIS-based model has been proven to be an efficient tool for formulating integrated and sustainable management plan.可再生淡水供给不足，是制约埃及未来农业与城市发展的主要瓶颈。埃及长期依赖的核心水资源为尼罗河。当前，地下水的供水占比正稳步提升，未来数十年间，其将占到总供水量的20%，尤其集中在尼罗河三角洲与河谷沿线的沙漠边缘垦殖区域。埃及的地下水开采具有动态特征：随着灌溉活动扩张、工业化与城市化进程推进，地下水开采量快速增长。西尼罗河三角洲便是此类区域之一，该区域多个点位均已开展地下水开采作业。为避免该区域含水层系统出现退化，亟需制定一套高效的集成化可持续地下水管理方案。高效的水资源集成化可持续管理，依赖于能够完整表征含水层系统特征的综合数据库，以及用于评估各类决策方案影响的建模工具。本研究针对西尼罗河三角洲的含水层系统，开发了一款基于地理信息系统（Geographic Information System, GIS）的模型。该GIS工具可提供分析功能与可视化能力，用于处理研究区域地下水建模所需的预处理与后处理信息。所开发的模型针对稳态与瞬态两种水文条件进行了校准，校准依据为过去20年间观测得到的历史地下水水头数据。经校准后的模型被用于评估地下水潜能，并针对西尼罗河三角洲含水层系统的保护需求，测试了两种备选管理方案。第一种方案为：减少地表水输入量，同时将地下水年开采量提升约4.5亿立方米，并优化灌溉系统，该方案可使含水层净补给量提升约5.7%，但会使含水层潜能降低约91%。第二种方案为修建新运河，该方案可使含水层年潜能提升约23%。实践证明，这款基于GIS的模型是制定集成化可持续水资源管理方案的高效工具。