BY ANGELJEAN CHIARAMIDA
---- — SEABROOK — It’s been years since the adequacy of the water supply has been an issue in town, but dry weather and depleting production at old wells has officials moving both to improve the condition of aging wells and search for new ones.
John Bell and Doug DeNatale from AECOM Technology Corporation met with selectmen on Monday to discuss the issues that are worrying water superintendent Curtis Slayton and well operator George Eaton.
In 2008, after a couple of very rainy springs, town well levels were doing fine, according to Slayton. But since 2009, when springs and summers grew dryer, well levels have been dropping, he said. In addition, some of the town’s wells are getting on in age and feeling the effects.
Production at some old wells is depleting, the men said. Bedrock well 4, for example, which is more than 40 years old, is producing less than half of what it once did. According to Eaton, bedrock 4 once pumped 250 gallons of water a minute in its prime, but today it’s only coming up with about 100 gallons a minute.
Demand for water is growing to accommodate an expanding year-round residential population that swells even more in the summer months, and an increasing commercial sector that includes new shopping centers and a nuclear power plant.
The power plant alone consumes about 60 million gallons annually, Slayton said, or about 20 percent of the 340 million total gallons the town uses during a year. At any time of the year during refueling or for other reasons, the power plant can have huge water demands, Slayton said.
He can get a call a day or so in advance from NextEra Energy Seabrook nuclear power plant personnel advising him that within a day or so the plant will need as much as from 100,000 to 300,000 gallons of water. Eaton added that this spring, during the month the plant powered up after being shut down for refueling, it consumed millions of gallons of water.
During most of the year, Slayton said, the town’s water needs can be filled by pumping about 1 million gallons of water a day to satisfy residents and businesses. But during the summer, demand can grow to about 1.9 million gallons a day, which is uncomfortably close to the town’s maximum pumping capacity of about 2.13 million gallons a day. And that’s only if all wells are producing and water levels are satisfactory.
”We’re good 10 months of the year,” Slayton told selectmen. “But July and August are very scary at times.”
Since 2000 the levels of Seabrook’s wells have been dropping due to rainfall issues, DeNatale said, and things are getting even dicier because some wells were sunk in the 1960s and 1970s. The placement of the town’s wellfields — in the western part of town — is also a worry, as the recharge area is not covered with the type of soils that readily allow rainwater or snow melt to perculate down to the aquifer quickly.
”You have a lot (of wells) but they’re drought sensitive,” DeNatale said. “In Seabrook’s case, it’s true: You can’t have enough water. You don’t want to turn manufacturers away (from siting in town) for lack of capacity.”
In 1965, when the town was enduring a drought while experiencing a growth period, it took four years to find and bring on a new well, he said. He strongly recommended the town be “proactive and not reactive” when it comes to dealing with its growing water needs.
Bell and Denatele presented selectmen with a multi-option plan that includes testing new wells in existing wellfields that already have productive wells. They also recommended replacing bedrock well 4, which has lost so much of its yield.
After the presentation on Monday, selectmen OK’d spending $24,000 to perform short-term pump tests on three existing bedrock test wells at the Riley, BMX, Gun Range wellfield sites to estimate the supply potential and analyze water quality. Logic indicates that these three test sites in areas already proven to have access to the aquifer will show potential for the sinking of permanent wells to augment the town’s water supply.
The experts are looking for the pump tests to indicate one or all of the test wells will produce at least 150 gallons of water a minute each to make them worthwhile to pursue.
The pump testing should be conclusive in about two months, Bell and DeNatale said, when they will return with their report to selectmen, and the next steps will be decided.
Replacing bedrock well 4 is another option on AECOM’s plan. Installing up to two test wells adjacent to the existing, failing well to replace it would cost about $87,000, Bell estimated.
Selectmen will look at this again in two months, they said, after they learn the results of the approved pump testing.