Wednesday, March 30, 2011
Risk for New England Floods Rises with Water Tables
As another spring flood season approaches in New England, a recent study by University of Massachusetts Amherst geoscientists suggests that soil moisture and the water table have been rising over the past 10 years across the region, and we may be facing a higher risk of flooding in the years ahead, due to changes in subsurface water storage over the longer term.
Hydrogeologist David Boutt, an expert in the mechanics and flow paths of subsurface water, with UMass Amherst graduate student Kaitlyn Weider, recently published in the journal Geophysical Research Letters the first instrument-based, long-term compilation and evaluation of the water table at a regional level over the last 60 years in New England. Evidence suggests that climate change is modifying the timing and nature of precipitation and altering the hydrogeologic cycle, the researchers say.
It is widely accepted that rising temperatures and the timing of rain and snowfall in New England are changing the character of the seasons, but there has been little study of how this might affect regional surface and ground water levels, Boutt notes. Variables such as streamflow, lake levels and timing of peak low and high flows are continually changing and could well be affected, he adds.
Using data from wells, stream gauges, precipitation monitors and weather-station temperatures collected between 1940 and 2010, he and Weider compiled the outlook for New England. They also show how researchers in other areas can use such information with statistical modeling and analyses to assess risk in their region.
Boutt and Weider collected ground water data from nearly 100 wells with at least 20 years of continuous monthly records in the Climate Response Network from various geologic and climatic regions of Maine, New Hampshire, Vermont, Massachusetts, Connecticut and Rhode Island. Overall, 78 percent of these sites provided at least 40 years of data.
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