The September – October 2012 issue of Groundwater, published by the National Groundwater Association, contains an errily prescient article by Vithanage and others (2012) regarding the effects of the 2004 Sumatran tsunami on a coastal aquifer in Sri Lanka.
The authors describe the sudden inundation of the Sri Lankan shoreline with seawater during the tsunami itself, and the inefficient process of oceanic recession following the event. Some oceanic water was trapped inland, in closed topographic depressions. Other seawater flooded buildings, engineered stormwater facilitates and entered imperfectly sealed water wells.
Pooled seawater and wells came to act as effective point-sources of salt water intrusion. While the authors document and forecast a slow water quality improvement and return to potability through time, clearly from the available data drinking water supply wells were rendered suddenly non-potable.
Tsunamis are not the only event that can cause sudden saltwater intrusion. Recent Hurricane Sandy generated a storm surge of several feet along much of the Mid-Atlantic and Northeastern USA coastline, particularly along the Jersey Shore, Long Island and southern New England. Coastal lands overlying shallow, unconfined aquifers may have been inundated by several feet of saline floodwater. As in Sri Lanka, manmade features may have combined with natural topography to trap a certain percentage of the seawater, giving it time to <a href="http://www.ecobine.de/print.php?SESSID=5d7092d85d384778d6c3226dcb5d3204&id=3.5 look at this site.3.3.1&kurs=11&l=en” target=”_blank”>percolate downward into the subsurface.
ALWI believes that owners of shallow shoreline wells, and other wells that were sumberged, should assume some measure of saltwater intrusion until facts prove otherwise. Sodium, chloride, condctivity, total dissolved solids, total suspended solids and salinity are low-cost laboratory tests to perform. If concentrations of these parameters are detected that seem anomalous, please call us as we would he happy to help you interpret the results and plan appropriate remedies.