Water Quality Committee Dives Into Waquoit Bay History
Falmouth Water Quality Management Committee met on Monday afternoon, March 28, to discuss the history, observed changes, and potential avenues toward the revitalization of Waquoit Bay.
A delegation from the Citizens for the Protection of Waquoit Bay attended the meeting, making about a dozen attendees in the audience.
“This is Waquoit Bay day,” said Eric T. Turkington, chairman of the committee. “It started with a request by your folks to talk about why we’re not doing enough for Waquoit Bay and it sort of coincided with a piece of work we had asked [Jordan] Mora [for], once we discovered the kind of work she does and the kind of work she was doing. We said you’re doing something very much appropriate to what these folks are talking about, so why don’t we do them together.”
Noah Clemens, a resident of Waquoit and member of CPWB, said that the organization’s subcommittee on alternative technologies for nitrogen remediation is looking to collaborate and coordinate their efforts with the water quality committee.
“With the proposals for SNEP (Southeastern New England Program) funding being one of the agenda items, we would like to encourage the committee to consider Waquoit Bay in its proposals,” Mr. Clemens said.
While no formal request was made, Mr. Clemens and other CPWB members urged the committee to consider the critical position Waquoit Bay is in when it comes to water quality, both in terms of importance and severe deterioration. Waquoit Bay, he said, is the Cape Cod Commission’s top priority watershed for its Section 208 Area Wide Water Quality Management Plan.
“Our subcommittee has also been looking into alternative technologies, such as floating wetlands,” Mr. Clemens said. “This is a technology that we don’t know if it’ll work in the marine environment. There’s lots of data and research that have been done in freshwater environments and it’s incredibly encouraging… what we don’t know is [if] in a tidal marine environment, whether the same tremendous amount of nitrogen removal for the cost would translate.”
CPWB has been looking into the possibility of a pilot project for the Moonakis River, he said, particularly because it contributes 25 percent of the freshwater that enters Waquoit Bay.
“We’d like to be able to see whether something could work there,” Mr. Clemens said. “We would like both the support of the committee in that I can’t tell you whether it will work as well in the marine environment as it does in the freshwater environment. But until we try it out, until we have a pilot project, I would hate to foreclose that as an alternative because it is pretty encouraging.”
Committee member Thomas Duncan noted that Falmouth shares Waquoit Bay with Mashpee, which, he said, to his knowledge, is responsible for around 40 percent of nitrogen-loading in the bay. Mr. Clemens said that the Childs and the Moonakis/Quashnet rivers contribute about 35 percent of the freshwater to Waquoit Bay.
“The daily nitrogen load from just those two sources is over 51 kilograms per day, which is above the target TMDL (total maximum daily load) for Waquoit Bay as a whole,” he said. “So if we can address just those small areas, that type of remediation will have an effect on the bay as a whole, which is one of the reasons we have been focusing on that.”
A graphic showing the amount of nitrogen required to be removed from each of the 14 estuaries in the area has been used as a guideline for treating the 14 estuaries in the area, Mr. Turkington said. The chart was created using numbers that come directly from the Massachusetts Estuaries Project studies done for each water body. The areas he said the town has been focusing on were the five water bodies with the highest amount of nitrogen required to be removed: Little Pond, Great Pond, Green Pond, Bournes Pond, and Waquoit Bay.
The town has already treated Little Pond, which required 5,000 kilograms of nitrogen to be removed annually—of which they reduced by 88 percent through sewering. Next on the chart, Mr. Turkington said, is Great Pond for two reasons: it is geographically close to existing pipelines and it exceeds all other water bodies in its requirement of nitrogen removal, clocking in at 12,155 kilograms each year.
“Waquoit Bay has a few problems, which is why you’re not first,” Mr. Turkington said. “First problem is you’re far away... the other problem is that half of Waquoit Bay is in Falmouth; the other half is in Mashpee.”
Mr. Turkington said that the committee has been working with Mashpee to delineate who is in charge of what percent of nitrogen loading to the bay, but implementation has not been as easy.
“The Mashpee selectmen have been helpful and cooperative [but] the Mashpee sewer commissioner just quit,” he said. “We sent them a draft agreement and then haven’t heard from them since. We’re doing our part to at least set the framework up of who’s going to take care of how much, because there’s no point in Falmouth spending millions and millions and millions of dollars and then saying, ‘Well, Mashpee hasn’t done anything.’ We’re a team on this one and we’re going to have to work together with them.”
Various CPWB members spoke to the fact that the group is not looking for specific SNEP funds at this time because of the lack of data regarding success of this type of program in marine environments, but wanted to bring their initiatives to the committee’s attention.
“We understand the problems with sewering Waquoit Bay,” one member said. “It’s a long way away, it’s incredibly expensive, the town is not going to support it in terms of funding… the reason that we formed [a subcommittee] is to provide some remediation in the short term because if we wait for funding to be available and for sewering to be available in Waquoit, whether it’s from Mashpee or Mashpee and Falmouth… we’re going to have a completely deteriorated bay by the time the sewers are in place and it’s going to be too late. We want to get moving on this and we’re going to do whatever we can in terms of reducing the nitrogen.”
After the discussion, the meeting transitioned into a presentation by Ms. Mora on the shifting dynamics in Waquoit Bay over time. Ms. Mora formerly worked for the Waquoit Bay National Estuarine Research Reserve and is now with the Association to Preserve Cape Cod. She presented research done with Matthew Long of the Woods Hole Oceanographic Institution.
A majority of the presentation consisted of data drawn from research at WBNERR. It took a look at the broad spectrum of changes in Waquoit Bay over the past 20 or so years, using data from various studies and reports to show the stark decline of the ecosystem.
Using four monitoring sites from the System Wide Monitoring Program, or SWMP, and the Waquoit Baywatchers program, samples were taken between mid-May and mid-October for a number of years and analyzed and provided the groups with what Ms. Mora called “interesting results” over the years.
Overall, the results showed a total increase in nitrogen presence in Waquoit Bay. Ms. Mora said that even the numbers seen in the MEP study are much lower than what one would see in the estuary today. There has been a shift in the ecosystem, with results showing a shift in primary producers from macrophytes to phytoplankton. Results also showed stark decline in macroalgae and eelgrass, which were once largely present in the bay’s main basin, and an increase in chlorophyll.
“I feel like this is a pretty compelling story right here, showing us that it seems that primary production, where photosynthesis is happening in our estuary, has really changed from the bottom to more of the water columns,” she said.
Ms. Mora said that water temperature has also steadily increased over time, something that can likely be attributed to the effects of global warming. She also noted that dissolved oxygen levels in the water are decreasing, with Sage Lot Pond having the highest rate of decline in dissolved oxygen levels.
Presenting another way of thinking about dissolved oxygen levels, Ms. Mora said that daily fluctuations in acidity are highly correlated with decreasing dissolved oxygen concentrations. A graph of daily patterns shows that the waters are generally warming throughout the day. In terms of dissolved oxygen, Childs River and Sage Lot Pond have both seen declines in respiration and photosynthesis rates.
Ms. Mora presented three graphs of Childs River, Sage Lot Pond, and Metoxit Pond, which they used to designate the middle of Waquoit Bay.
“What these graphs are showing us is that all across these three southern payments, when there’s lots of oxygen in the water, our pH is high during the day. Then at night when respiration is happening and carbon dioxide gets released into the water, and that’s where acidity takes place… as it would follow, if we know that oxygen is decreasing over time and we know that these two things are related. It’s not shocking that we’ve also found that the waters in Waquoit Bay are becoming more acidic.”
Extreme stress events are happening more often and working, Ms. Mora said. Looking at the 90th percentile in weeks for temperature maximums, data has shown that by 2020, significant heat wave events can last three or four weeks, as opposed to just one week in the early 2000s. Hypoxic events, when levels of dissolved oxygen are very low, are also lasting longer than they were a decade or so ago.
Based on the research presented, Ms. Mora presented a few conclusions: in areas where nitrogen is not properly managed, eutrophication continues to degrade ecosystems; TMDL numbers as taken by the MEP are now outdated and new models are needed to keep up with the changing environments; and management of water quality must remain vigilant, because it is unclear how quickly these ecosystems will respond to management strategy implementation.
The committee will meet again on April 25.