Edgartown wastewater project coming together

Consultants were brought in to explain the town’s current and projected future conditions.

Tighe & Bond consultants presenting Edgartown's wastewater situation at Edgartown Public Library. —Eunki Seonwoo

Although the full costs of implementing Edgartown’s 20-year comprehensive wastewater management plan isn’t fully realized yet, the project won’t be cheap. 

On Tuesday, Oct. 3, the Edgartown Wastewater Commission hosted the first of several meetings delving into the components of the management plan at the Edgartown Public Library. Representatives from the engineering consulting firm Tighe & Bond — Ian Catlow, Daniel Roop, and Brian Kiely — were at the session to present the information to the people. 

According to Catlow, there are several drivers of the comprehensive wastewater management plan, including potential population changes and infrastructure assessments within the 20-year planning cycle, the total amount of loading of nitrogen in Sengekontacket Pond and Edgartown Great Pond alongside changes to Title 5, a new state permitting process aimed at reducing nitrogen in coastal embayments. However, Catlow did point out Title V does not impact the Vineyard as much as other areas, for now. 

Additionally, there are several phases for the management plan, starting with an assessment of existing conditions and future conditions alongside a needs analysis. 

“If you want to talk about money — as a lot of people do as they’re thinking about these types of plans — where we really get into that is in phase two,” Catlow said, continuing that public input and a regulatory review would happen through the Massachusetts Environmental Policy Act process before the management plan is established. “Ultimately, where we want to be headed is to develop watershed permits for Sengekontacket and Edgartown Great Pond so we can manage nitrogen in those impacted watersheds and also develop a 20-year plan that helps the town move forward.” 

Catlow said the watersheds of greatest concern for Edgartown are Sengekontacket Pond and Edgartown Great Pond. The total Maximum day loads (TMDL) — which is the calculated highest amount of pollutants that a watershed can take in while maintaining a healthy system — for Sengekontacket is 16,757 kg of nitrogen per year and 16,812 kg of nitrogen per year for Edgartown Great Pond. The maximum loads are based on the Massachusetts Estuaries Plan, a report from 2001 that chronicled nitrogen issues across the state.

The 2023 nitrogen loads for both watersheds are already exceeding those targets. The load in Sengekontacket is 18,742 kg of nitrogen per year and Edgartown Great Pond it’s 19,424 kg of nitrogen per year. 

Edgartown also shares these watershed areas with other towns. Sixty-four percent of the Sengekontacket watershed and 95 percent of the Edgartown Great Pond watershed are within Edgartown’s borders. The rest are from neighboring communities.

With this in mind, Catlow said there would be several options to look at to reduce nitrogen levels, such as the amount of nitrogen discharged from the town’s existing wastewater treatment facility and septic systems through “engineered solutions.” 

The consultants are also looking into other bodies of water for the plan, including Trapps Pond, Edgartown Harbor, Katama Bar, and Crackatuxet Pond. 

There are other factors that the consultants are looking at as well while preparations for Edgartown’s plan continues.

Edgartown’s population has grown over the decades with around 5,000 year-round residents and an estimated summer peak population of a little below 25,000. The number of year-round residents are expected to decrease between now and 2050 with a drop-off in the baby boomer population. Meanwhile, the projected peak summer population by 2050 is less certain, possibly remaining stable, increasing, or also decreasing. An increase in population could lead to more wastewater usage. In terms of development patterns, the downtown area has smaller properties that are bunched closer together with larger, more spread out buildings to the western portions of Edgartown. 

Additionally, there are issues that need to be considered for climate change risks and resiliency measures, such as an estimated 1.6 to 1.8 feet in sea level rise by 2050 and implementing upgrades to monitor pump stations that face flood risks. 

One of the major parts of developing the plan includes analyzing Edgartown’s wastewater system. Roop said alongside the Edgartown Wastewater Treatment Facility, the town has 10.05 miles of force main pipelines, 6.83 miles of gravity sewer pipelines, 9.7 miles of low pressure mains, around 500 e-One Grinder pumps, and eight pump stations. The peak daily flow from sewers and septic systems are also expected to increase in the next 20 years based on Title 5 regulations, although the septic flow increase will not be as high with more advanced treatment. The future flow projections are still being calculated. 

Roop listed several needed upgrades deemed from intermediate (e.g. structural repairs, replacing control systems, etc.) to high risk upgrades (e.g. providing a local electrical feed, major structural repairs, etc.)  that are needed for pump stations. The pump stations’ intermediate risk and high risk repairs are expected to cost $209,000 and $247,000 respectively. 

The next steps of developing a management plan include finalizing the future flow projections, completing a needs analysis, and identifying alternative options. 

There was also some time for attendees to ask questions. Some concerns that arose included whether a second wastewater treatment plant would be needed and the process of connecting existing homes to the town lines. 

When Edgartown town administrator James Hagerty asked for a ballpark range for project costs. Catlow did not have a number ready. However, Catlowdid share how much it cost the Cape town of Orleans to upgrade its sewer lines. 

“We just finished up phase one of Orleans’ buildout, which was a treatment plant for 250,000 gallons per day and … about five miles of sewer, and that cost them over $60 million,” Catlow said, adding that another phase for around five miles of sewer work costing around $24 million. 

Catlow added Edgartown being on an Island can also possibly increase costs when hiring contractors. However, there are funding mechanisms the town can look at, such as federal funding or the zero-interest state revolving fund loan. 

Orleans’ costs elicited groans from several meeting attendees. 

The next presentation is expected to happen in about a month.


  1. Great reporting. I was at this meeting and did not recall half of it until I read this article. Eunki Seonwoo captured everything that was said.

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