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Assessment of water quality and quantity of springs at a pilot-scale: Applications in semi-arid Mediterranean areas in Lebanon
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  • Joanna Doummar,
  • Marwan Fahs,
  • Michel Aoun,
  • Reda Elghawi,
  • Jihad Othman,
  • Mohamad Alali,
  • Assaad H. Kassem
Joanna Doummar
American University of Beirut

Corresponding Author:[email protected]

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Marwan Fahs
Strasbourg University
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Michel Aoun
American University of Beirut
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Reda Elghawi
American University of Beirut
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Jihad Othman
American University of Beirut
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Mohamad Alali
American University of Beirut
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Assaad H. Kassem
American University of Beirut
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Abstract

This work presents an integrated methodology for the assessment of threats on spring quality and quantity in poorly investigated Mediterranean semi-arid karst catchments in Lebanon. Pilot investigations, including 1) high-resolution monitoring of spring water and climate, 2) artificial tracer experiments, and 3) analysis of micropollutants in surface water, groundwater, and wastewater samples were conducted to assess flow and transport in three karst catchments of El Qachqouch, El Assal, and Laban springs. First, the high-resolution in-situ spring data allows the quantification of available water volumes, as well as their seasonal and yearly variability in addition to shortages and floodwaters. Moreover, the statistical analysis of hydrographs and chemographs helps assess the karst typology, spring type and hydrodynamic behavior (storage versus fast flow). Furthermore, a series of artificial tracer experiments provides information about key-transport parameters related to the intrinsic vulnerability of the pilot springs, while the analysis of micropollutants gives insight into the specific types of point source pollution as well as contaminant types and loads. On the one hand, the tracer experiments reveal that any potential contamination occurring in snow-governed areas can be observed at the spring for an extensive time due to its intermittent release by gradual snowmelt, even with enough dilution effect. On the other hand, the assessment of persistent wastewater indicators shows that springs in the lower catchment (including El Qachqouch) are highly vulnerable to a wide range of pollutants from point source (dolines and river) and diffuse percolation. Such contaminants breakthrough is challenging to predict because of the heterogenous duality of infiltration and flow, typical of karst systems. Finally, this set of investigations is essential for the proper characterization of poorly studied systems in developing areas, whereby results can be integrated into conceptual and numerical models to be used by decision-makers as support tools in science-evidenced management plans.
19 Dec 2022Published in Threats to Springs in a Changing World on pages 111-129. 10.1002/9781119818625.ch8