Modelling Combined Causes of Seawater Intrusion
The combined effect of sea-level rise and over-pumping on seawater intrusion in coastal aquifers is examined in an article published in the Journal of Water and Climate Change. The authors apply a numerical model to quantify the effects of various scenari
Water Link International
06/22/2011
Climate change, sea-level rise, over-pumping and saltwater intrusion present some of the future challenges of water resources management in coastal areas. Over-abstraction is considered to be one of the main causes of seawater intrusion; a high rate of population growth in coastal areas leads to excessive abstraction from the aquifers, resulting in the migration of saltwater toward the aquifers. Sea-level rise also threatens the groundwater resources in coastal aquifers as it imposes an additional pressure head on the sea side, which helps to move seawater into the aquifer and shifts the transition/mixing zone further inland. The combined impact of sea-level rise and over-pumping exacerbates the problem, which requires urgent solutions.
The authors H.F. Abd-Elhamid and A.A. Javadi describe previous research on the effects of climate change on seawater intrusion in coastal aquifers using various modelling techniques, noting that the combined effects of sea-level rise caused by climate change and water table decline caused by over-abstraction have not previously been studied. Two case studies – one hypothetical and another real – are investigated using a coupled transient finite element model. Three scenarios are considered for the latter case: (1) a rise in the water levels on the sea side due to climate change, (2) a reduction in groundwater table due to over-pumping and (3) the combination of sea-level rise and over-pumping.
Results show that the change of water level in the sea side affected the position of the transition zone. This effect is greater if the sea-level rise is combined with the decline in water table due to over-abstraction (scenario 3). In this case, the transition zone was shifted further inland. In the case of larger and deeper aquifers, the shift of the transition zone would be much greater and would result in further contamination of groundwater in coastal aquifers.
