The latest news about Maine lakes and ponds.

Windham Water Quality in Jeopardy

June 10, 2009 - WINDHAM -- Commercial development during the last 15 years has contributed heavily to groundwater contamination in North Windham, and the problem will continue to worsen unless the town takes action, including possibly constructing a sewer system, a hydrogeologist told the Town Council this week.

Nitrates from the many septic systems in North Windham, where there is no public sewer, are slowly seeping into the groundwater, raising nitrogen levels enough to cause concern, mainly in the area of Route 302 from Route 115 to Chaffin Pond, said Roger Gerber of Sebago Technics, who was hired by the town to interpret groundwater data produced by the U.S. Geological Survey.

"Groundwater quality has gotten generally worse," said Gerber, who looked at data taken from wells from 2003-2007. "Because the fact you don't have a sewer in this area, it's not unexpected."

While the water is not dangerous for drinking at this piont, Gerber's evaluation prompted the Town Council to consider sending letters to residences using wells in that area suggesting they test their water. Councilors will also likely revisit the idea of putting a public sewer system in North Windham, and could explore other ways to lessen contamination, such as requiring septic system filters in new developments.

"It's pretty apparent to me that we need to be looking at some form of public sewer through North Windham," Council Chairwoman Carol Waig said, echoing comments made earlier by Councilor Donna Chapman.

Higher than normal levels of sodium were also found in the water, Gerber said. That is due to the runoff of salt used on the roads and large parking lots in North Windham.

But the real problem are the nitrates, Gerber said. Though base levels of nitrate are typically around .25 mg/liter, he found the levels to generally be around 3-4 mg/liter, and others up to 5 mg/liter. Anything under 10 mg/liter is considered safe for drinking water, though once levels hit half that, and are trending upward, it is a good idea for a town to take steps to curb the contamination, he said.

"There's a big area there where there is definite impact of septic systems," said Gerber. The highest levels were found near the large septic systems used by "big box" stores like Home Depot and Wal-Mart, where a 20 mg/liter measurement was taken. While most residences in that area are on public water, a few private wells still exist.

"There could be some concern then," said Gerber. "It could extend hundreds of feet, possibly."

Both the town and the state Department of Environmental Protection require that new commercial developments show that nitrate levels will be below 10 mg/liter at the property line.

But groundwater and the flow of contaminants can be complicated, and the presence of so many large developments in North Windham can make predicting levels difficult, Gerber said.

The town can take some steps to help soften the problem, Gerber said. First, wells in the area should be tested for nitrate and sodium levels. To slow the rate of contamination, filters for septic systems can be required of all new commercial development, he said. Then, the town should consider a sewer system.

"It's not cheap, but it may be necessary if you want to continue to add commercial development," said Gerber.

"The solution is going to be one of policy, then if necessary, infrastructure," said Town Manager Tony Plante.

If the town is going to be sending letters to well owners, officials need to be ready to answer questions about contamination, Waig said.

"We better be able to be prepared about what that next step would be," she said.

By Ben Bragdon
Assistant Editor - Lakes Region Weekly , June 4, 2009


Lakes:
Regions: Sebago


Print this story

Email this story

return to Lake News