A New Normalized Groundwater Age-Based Index for Quantitative Evaluation of the Vulnerability to Seawater Intrusion in Coastal Aquifers: Implications for Management and Risk Assessments

Water

卷:13

Joanna Doummar¹  Mohammed Adil Sbai²  Marwan Fahs³  Abdelkader Larabi⁴ 

[1] Department of Geology, American University of Beirut, Beirut P.O. Box 11-0236/26, Lebanon;

[2] Independent Research Scientist, 45000 Orléans, France;

[3] Institut Terre et Environnement de Strasbourg, Université de Strasbourg, CNRS, ENGEES, UMR 7063, 67081 Strasbourg, France;

[4] Regional Water Centre of Maghreb, LIMEN, Ecole Mohammadia d’ingénieurs, Université Mohammed V de Rabat, Avenue Ibn Sina, B.P. 765, Rabat 10090, Morocco;

关键词: coastal aquifers;    seawater intrusion;    vulnerability index;    groundwater age;    zero vulnerability line;    coastal aquifer management;   

DOI  :  10.3390/w13182496

来源: DOAJ

【 摘 要 】

The vulnerability of coastal aquifers to seawater intrusion has been largely relying on data-driven indexing approaches despite their shortcomings to depict the complex processes of groundwater flow and mass transport under variable velocity conditions. This paper introduces a modelling-based alternative technique relying on a normalized saltwater age vulnerability index post-processed from results of a variable density flow simulation. This distributed index is obtained from the steady-state distribution of the salinity and a restriction of the mean groundwater age to a mean saltwater age distribution. This approach provides a novel way to shift from the concentration space into a vulnerability assessment space to evaluate the threats to coastal aquifers. The method requires only a sequential numerical solution of two steady state sets of equations. Several variants of the hypothetical Henry problem and a case study in Lebanon are selected for demonstration. Results highlight this approach ability to rank, compare, and validate different scenarios for coastal water resources management. A novel concept of zero-vulnerability line/surface delineating the coastal area threatened by seawater intrusion has shown to be relevant for optimal management of coastal aquifers and risk assessments. Hence, this work provides a new tool to sustainably manage and protect coastal groundwater resources.

【 授权许可】

Unknown