Why Sewers are a Loser for Acton

Acton had a sustainable water system in the past. Now we are at risk of throwing it away.

Acton had an unbeatable combination for keeping water local. Our water came from local wells drilled in local aquifers, moved on to local leach fields, and slowly made its way back in to the aquifers, having had enough time and space to be filtered clean.

We still have local water, but we are starting to throw it away by switching over to sewers. Our first town sewers started flowing in 2002, bringing wastewater to the new treatment plant on Adams Street. This facility discharges so close to the Assabet river that virtually all of that water finds its way to the river, and moves quickly on to the Concord river, the Merrimack river, and out to the Atlantic Ocean. Shipping out this water reduces the amount of water we have available in our wellfields, compared to the former use of leach fields.

The Acton Water District is allowed by the state to withdraw an average of 1.96 million gallons of water per day. This legal limit is somewhat arbitrary, but there is a real physical limit. On days when water use gets up to and beyond 2.4 million gallons per day, the District reports that storage tanks start dropping and water pressure starts falling. Our ground water supply is not unlimited. Our current waste water treatment plan is built to process more than 10% of that permitted withdrawal volume — our initial permit was for up to 250,000 gallons per day. That's water that's not coming back any time soon.

Most of the legal limit is simply calculated by looking at our water withdrawals in the past, and is not related to our actual sustainable withdrawal limits. In particular, our legal withdrawal limit was not reduced after our waste water treatment plant started operating.

What is a safe limit for how much we withdraw, and how is that related to how much we send away in our sewer system? No one really knows. Because waste water treatment is a municipal responsibility, and water supply is a water district responsibility, there is no one agency in charge of modeling our overall water flows and making sure we are not getting ourselves in trouble. The closest we have gotten is the state-mandated and Town- and District-written Comprehensive Water Resources Management Plan, which computed a preliminary “Acton Water Balance” — but this was done before the sewers were operating.

We need to support further cooperation between the Town and the Water District to refine our understanding of what is safe and sustainable for Acton. In the absence of any more formal modeling, all we can guess is that keeping our water is better for our safe withdrawal limits than shipping it off to Concord and beyond. Bringing water quality in to the discussion adds different considerations, but that's for a future column. From a water quantity standpoint, more sewers are going to be problematic for Acton.

In this blog, I'll be looking at environmental issues in Acton. In future articles, I plan to discuss air quality, energy production, climate change, sprawl vs. clustering, transportation, energy use in our homes, and more — always from an Acton perspective. And we need to return to sewers to talk about water quality, and the development that follows sewers, and about alternatives to sewers. I'm not an expert on any of this, so I will need your feedback to keep getting the facts straight. Let me know using the comment form, or just give me a call or an email. I can be reached at 978-266-9409 or at jimsg@newview.org


A Complex Subject Area

You have touched on many different aspects of the total water management issue in Acton. It ultimately encompasses the management of wastewater, stormwater and what we often call drinking water. The EPA wants states and municipalities to look and treat all of the above as resources. We're not there yet.

There is still a lot of thinking that "all sewers are good." In some circumstances, a sewer system makes very good sense and, in fact, may be necessary. However, at the time that the Acton system was built, there had already been a shift by planners to look at on-site or local treatment using the newer, modern technologies that had been proven to be effective. In some cases this meant a number of residences could be "clustered" together for cost effective wastewater treatment while other homes could have their septic systems modified with one or more of these new technologies.

You did mention that modeling was involved in developing the CWRMP. I, for one, would like to understand the model. [I've had a bit of experience in developing mathematical models of biological systems in the past.] It seems that the model used is not provided because it is considered proprietary. That's nice. So, how does the town know that it is correct and providing good data to us?

I'm glad to see that you are thinking about this complex topic and that you plan to re-visit and write about it some more in the future. One could spend considerable time discussing total water management.

B. Rosen

Sewers a loser for Acton

I think this is a good start to a conversation. A great deal needs to be done in Acton to better manage its water resources.