Greg Woods, Lincoln Water Department superintendent, with one of the membrane filters used to treat clean the town’s water. See below for more photos. —Photos by Alice Waugh
By Alice Waugh
You don’t have to think about it — just turn on your tap and clean water flows. For most Lincoln households, that water starts its journey in Flint’s Pond and navigates a surprisingly intricate route on its way to your shower, sink or lawn — a journey that once involved wooden water mains and a coal-fired pump.
All but about 400 Lincoln residents (mostly on Old County Road and Conant Road) get town water, which is pumped from Flint’s Pond via a pump house next to the pond, explained Lincoln Water Department Superintendent Greg Woods. From there, it travels north across Sandy Pond Road to a nondescript one-story building where an automated system adds sodium hydroxide to adjust the pH, sodium fluoride to help prevent tooth decay, and zinc orthophosphate to reduce corrosion in the water pipes.
Then all the water — anywhere from 450,000 to 900,000 gallons a day — passes through a membrane filtration system before heading to a 20-foot-tall holding tank at the top of a hill on Bedford Road. (The 1.2-million-gallon tank won’t offend anyone’s aesthetic sensibilities, however; all but two feet of it are buried underground.) From there, the treated and filtered water flows through Lincoln’s 57 miles of water mains to residents’ faucets.
There are several safety and backup systems in place to keep the water flowing in case of emergency. The pump house has an emergency backup generator that runs on natural gas in case of a power outage. In the aftermath of Hurricane Sandy, it kept the water flowing for three full days, Woods said. There’s also a well on Tower Road that serves as a secondary water source when the main facility requires maintenance. And the system’s water is sampled every two weeks at various locations in town and tested to make sure the chemistry is correct and that there are no harmful pathogens present.
More than a century of service
Lincoln has had a water department since 1874. In the old days, water was drawn from the pond, screened in the small house at the water’s edge and pumped directly to homes via a coal-fired facility that was torn down in 1900, Woods said. Today, the larger building houses the modern pumping facility and generator as well as repair equipment and an assortment of old water meters and gate boxes — the metal tubes set into roadway and sidewalks with caps that workers can remove to access each gate, or valve, to shut off water between two points.
The state Department of Environmental Protection eventually began requiring towns to disinfect surface water that’s piped to homes (water from public and private wells below a certain depth doesn’t have this requirement), so Lincoln built the disinfection facility in 1993 and added the membrane filtration system in 2003. The disused screening building next to the pond is still there, although it started sliding off its foundation about 15 years ago and a resident paid to have it filled with cement to anchor it in place.
The pond itself is closed to all recreational use including swimming, fishing, skating and even picnicking by the shore. “I don’t want to be a Nazi and shoo people away because it really is a beautiful sight, but it is our main water supply,” Woods said.
Owing to the lack of human predators, “there are some really big fish in there,” said Woods. The pond is about 35 feet at its deepest, and one can see down about 15 feet from the surface. “It’s a very, very clear pond,” he said. Canada geese visit now and then, but he chases them off in a boat to minimize bacteriological contamination from bird poop.
Conservation measures
Not surprisingly, residents use a lot more water in the summer, when lawns and gardens get their share. In fact, the time of day with the highest demand is at about 3 a.m., because many homeowners have their sprinkler systems hooked up to timers that are set to soak the plants in the middle of the night, which is better for them than getting water in the heat of the day. There’s also a morning and evening rush, when residents are taking showers, using toilets, cooking meals and doing the dishes.
At first glance, Massachusetts doesn’t seem to resemble the Southwest in terms of water supply, but, “there are some very stressed water basins in the state,” Woods said. By state law, residents are supposed to limit themselves to 65 gallons of water per person per day, and Lincoln “has been hanging out in the upper 60s,” he said. Over the course of a year, Lincoln uses 200 million gallons of town water, but the town is supposed to reduce its usage to 182 million gallons to comply with current regulations.
Although there are no specific penalties at the moment, towns must show they have plans in place for conservation and leak detection and are making progress. In Lincoln, sandwich boards appear around town during the growing season to remind residents that they may use outside water only twice a week. Some residents get around the limit by using a private well for outdoor irrigation and town water just for indoor use, Woods noted.
Another state-mandated water conservation rule says that no more than 10 percent of pumped water may be lost to leaks somewhere in the system. Lincoln loses somewhere between 10 and 20 percent each year, “so we need to find some leaks,” Woods said. The town must repair leaks up to each owner’s property line, but homeowners are responsible for fixing pipes on their property.
If townwide water usage town suddenly spikes, workers will look for an underground leak by listening from surface points between hydrants with headphones to try to pin down the location of the suspected leak (though sometimes it remains a mystery — see the Lincoln Squirrel, Aug. 17, 2013). Water escaping from a crack in a pipe agitates the surrounding sediment, which causes vibrations that can be picked up on sophisticated detection systems. A contractor also inspects the entire system using this method once a year and identifies, on average, about a dozen locations annually (including faulty hydrants) that are leaking more than one gallon a minute, Woods said.
Leaks are a never-ending issue because many of the water mains are quite old, but it’s prohibitively expensive to replace them before they actually fail. The original water mains were made of wood strips held together with metal bands, because cast iron was very expensive back in the day. The town eventually moved to cast iron pipes and, more recently, longer-lasting ductile iron.
“We have pipe in the ground that’s more than 100 years old,” said Woods, pointing to an ancient pipe segment that had become drastically narrowed from the inside by iron and manganese deposits. Nowadays, water mains are flushed once a year by opening hydrants. This creates an artificial leak that causes the system to pump water at higher pressure to compensate, and the temporary rush of water scours the deposits the inside the pipes.
Though it’s safe to drink, the water that day might be a bit discolored, so notices are posted about when hydrant flushing will take place. “You don’t want to launder your silk curtains that day,” Woods said.
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Photos by Alice Waugh