Study co-author Kaitlyn Weider: "I would say more flooded basements are on the way."
FILE | 06.23.2008, Chicopee – Mary M. Regan vacuums water in her home at 23 Brooks Ave., Chicopee, after heavy showers caused her basement to flood.AMHERST – New England may be facing a higher risk of flooding because of groundwater levels that have been rising in recent years, according to geologists at the University of Massachusetts.
Groundwater levels were relatively stable until 10 years ago, and the most recent decade produced “consistently above normal precipitation, stream flow and ground water levels,” reports a study recently published in the journal Geophysical Research Letters.
The study was authored by David F. Boutt, a hydrogeologist and assistant professor, and Kaitlyn M. Weider, a graduate student in geology.
“Climate in New England is changing and has been changing over the last 100 years,” said Weider, who did the statistical work for the study as part of her master’s thesis.
“More precipitation is falling as rain and less as snow with average annual precipitation displaying a gradual increase of 5 to 10 percent across the Northeast” since the early 1900s, she said.
The researchers based their study on historical data covering the past 60 years in New England.
They looked at data from about 100 groundwater monitoring wells, 43 temperature sites and 75 precipitation stations. They also took surface water flow information from 67 stream gauges. About 20 of the wells they considered were in the Pioneer Valley.
On average, the water level in the wells rose 1.4 feet over the length of time records were kept, which was more than 20 years at all the wells, Weider said. When the water table is higher and storms occur, water is less likely to be absorbed into the ground and more likely to cause flooding.
“We are expected to receive more frequent and intense precipitation events in the next 50 years,” she said. “I would say more flooded basements are on the way.”
Rising temperatures have changed the character of the seasons in New England and altered the nature of storms over time.
For instance, records show that, on average, snow and ice melt earlier in the spring now than in past centuries.
In his book “Walden,” Henry David Thoreau chronicled the dates upon which ice completely disappeared from Walden Pond in Concord in the spring in the mid-1800s. The average date was about April 1. An ongoing study in recent years has found the last ice date now is typically two to three weeks earlier.
However, until now, there has been little study of how these weather changes are affecting regional surface and ground water levels.