Charles River Sets Record Lows, Groundwater Dwindles

NEWTON, MA - The Charles River and many others in eastern Massachusetts set record low levels for water flow in May and June 1999. According to the Charles River Watershed Association (CRWA), the Charles currently is flowing at one-third the volume it typically does this time of year, due to lack of rainfall and depletion of underground water supplies that replenish the river.

On Friday, June 11, the flow of the Charles in Dover dropped to 1.5 million gallons per hour, smashing the previous low flow record of 2 million gallons per hour since 1937.  Flow is gaged by the US Geological Survey at stations on rivers throughout Massachusetts and Rhode Island. Of the 33 stations with long-term flow statistics, the current flow is 33% of the median, or what it should be this time of year. Only those rivers with significant wastewater discharges or dam controls are over 50% of median flow.

Rainfall is well below normal for much of Massachusetts, contributing significantly to low flows.  Boston is experiencing one of the driest months on record, with only traces of rain during one of the most important seasons for replenishing groundwater that feeds the river. Last winter’s snowfall was also below normal, contributing to very low spring runoff to rivers.

Aquifers, or underground lakes that supply much of the drinking water in eastern Massachusetts, are linked to rivers and produce river flow when no precipitation occurs.  Public and private wells withdraw water from these aquifers which is why many towns are instituting outdoor watering bans or restrictions. As more water is withdrawn, groundwater levels decline and less water reaches rivers as baseflow.

"We’ve disconnected rainwater from groundwater, which is what recharges our aquifers," explains CRWA’s Executive Director Robert L. Zimmerman, Jr.  "Rainwater can’t penetrate pavement and rooftops. As a result, groundwater levels decline and rivers run dangerously low in the summer."

The Charles River Watershed Association encourages homeowners and businesses to conserve water and curtail outdoor watering, even in areas where no official ban has been designated. For more information, visit CRWA’s website at www.crwa.org.