The study of water quality and the quantification of reserves and their variations according to natural and anthropogenic forcing is necessary to establish an adequate management plan for groundwater resources. For this purpose, a modeling approach is a useful tool that allows, after calibration phase and verification of simulation, and under different scenarios of forcing and operational changes, to estimate and control the groundwater quantity and quality. The main objective of this study is to collect all available data in a model that simulates the Jeffara of Medenine coastal aquifer system functioning. To achieve this goal, a conceptual model was constructed based on previous studies and hydrogeological investigations. The regional groundwater numerical flow model for the Jeffara aquifer was developed using MODFLOW working under steady‐state and transient conditions. Groundwater elevations measured from the piezometric wells distributed throughout the study area in 1973 were selected as the target water levels for steady state (head) model calibration. A transient simulation was undertaken for the 42 years from 1973 to 2015. The historical transient model calibration was satisfactory, consistent with the continuous piezometric decline in response to the increase in groundwater abstraction. The developed numerical model was used to study the system's behavior over the next 35 years under various constraints. Two scenarios for potential groundwater extraction for the period 2015–2050 are presented. The predictive simulations show the effect of the increase of the exploitation on the piezometric levels. To study the phenomenon of salinization, which is one of the most severe and widespread groundwater contamination problems, especially in coastal regions, a solute transport model has been constructed by using MT3DMS software coupled with the groundwater flow model. The best calibration results are obtained when the connection with the overlying superficial aquifer is considered suggesting that groundwater contamination originates from this aquifer.

中文翻译：

---

利用MODFLOW和MT3DMS在干旱和半干旱地区进行地下水管理的水文地球化学模型：以突尼斯东南部美登宁沿海含水层的Jeffara为例

为了建立适当的地下水资源管理计划，有必要对水质进行研究，并根据自然和人为强迫对储量及其变化进行量化。为此，建模方法是一种有用的工具，可以在校准阶段和模拟验证之后，在强迫和运行变化的不同情况下，估算和控制地下水的数量和质量。这项研究的主要目的是在一个模型中收集所有可用的数据，该模型可模拟梅德宁沿海含水层系统的Jeffara。为了实现这一目标，在先前的研究和水文地质调查的基础上构建了一个概念模型。利用MODFLOW在稳态和瞬态条件下工作，开发了Jeffara含水层的区域地下水数值流模型。从1973年分布在整个研究区域的测压井测得的地下水高程被选为稳态（水头）模型校准的目标水位。从1973年到2015年进行了42年的瞬态模拟。历史瞬态模型的校准令人满意，这与由于地下水采出量增加而引起的连续测压下降是一致的。所开发的数值模型用于研究在各种约束下未来35年系统的行为。提出了2015-2050年期间可能开采地下水的两种方案。预测模拟显示了开采量增加对测压水平的影响。为了研究盐渍化现象，这是最严重和最普遍的地下水污染问题之一，尤其是在沿海地区，通过结合MT3DMS软件和地下水流模型构建了溶质运移模型。当考虑与上层浅层含水层的连接表明地下水污染源于该含水层时，可获得最佳校准结果。通过使用MT3DMS软件和地下水流模型建立了溶质运移模型。当考虑与上层浅层含水层的连接表明地下水污染源于该含水层时，可获得最佳校准结果。通过使用MT3DMS软件和地下水流模型建立了溶质运移模型。当考虑与上层浅层含水层的连接表明地下水污染源于该含水层时，可获得最佳校准结果。