‘It’s totally gone’: Mashpee’s water quality at an all-time low, report finds

Jessica Hill
Cape Cod Times
Jul 29, 2021

MASHPEE — The biggest takeaway from Mashpee’s latest water quality report is pretty dire: water is highly polluted and it will continue to get worse until action is taken.

“Sorry,” said professor Brian Howes, who teaches estuarine and ocean sciences, of the findings in the report. “I live here too. It makes me sad.”

Howes is a professor from UMass Dartmouth who gave a presentation Monday at the board of selectmen meeting about a report on the town’s water quality.

The 47-page report published in late June is part of the Mashpee Water Quality Monitoring Program, a collaborative effort between the Mashpee Wampanoag Tribe, the town of Mashpee and the Coastal Systems Program within the UMass Dartmouth, the report states.

The program collects and analyzes water samples within Waquoit Bay and Popponesset Bay systems to look at short- and long-term trends in the water quality and develop nitrogen management plans to help solve the problem.

Howes has given multiple water quality reports to Mashpee over the years, and for the first time in 20 years, he had “nothing good to say,” he said.

Howes and his team found some sobering results. The water quality in the estuaries is the worst on record, and it is widely due to human actions.

Nitrogen from septic systems, law fertilizers are worsening the water quality
The report found that nitrogen enrichment that is flowing into bays mostly from septic systems and lawn fertilizers are major contributors to the worsening water quality.

As the development increases in Mashpee, and especially developments with septic systems, the amount of nutrient pollution entering the estuaries will continue to increase, Howes said.

The report analyzed water samples from the Popponesset Bay system, which includes Mashpee River, Shoestring Bay, Ockway Bay, Main Bay, Pinquisset Cove, Popponesset Creek, Sanuit River, and the Waquoit Bay system, which includes Hamblin Pond, Jehu Pond, Main Bay, Childs River, Eel Pond, Quashnet River and Red Brook.

No high water quality areas remain, and there is general impairment throughout both estuaries, Howes said. Over the last five or 10 years, there has been a gradual decline in water quality in the lower basins, and the upper tributary regions remain significantly impaired.

Quashnet River is “unbelievably high” in nitrogen, Howes said, and there is no high water quality remaining in Waquoit Bay.

“It’s totally gone,” he said.

Between 2010 and 2020, Popponesset Bay has exceeded the regulatory threshold for the amount of nitrogen allowed by the Massachusetts Department of Environmental Protection and the Environmental Protection Agency every year, he said.

Popponesset Bay has large and significant nitrogen enrichment in the upper tributaries and throughout the bay, and it has seen a 100% loss of eelgrass, he said. There is some good habitat remaining, but not great, he said. It would be deemed unhealthy and is considered moderately impaired.

The habitats are degrading, and Mashpee will lose its fish populations, he said. The town has already started to lose fish, he said.

As a result of the pollution, the frequency and magnitude of algal blooms are increasing in Mashpee and and across the region, he said.

Residents and visitors have seen the effects firsthand of the cyanobacteria blooms caused by nitrogen enrichment. Signs have gone up in Ashumet and Santuit Ponds alerting people to the harmful blooms and prohibiting swimming.

Many residents are well aware of these long-standing issues with the town’s water quality. Tribal members have spoken about fewer fish in the ponds, older residents have noticed the changes over the last few decades and organizations have even filed lawsuits against the town due to its polluted water bodies.

“There is nothing improving,” Howes said. “Why would it? We haven’t done too much.”

Solutions to halt or slow down nitrogen pollution
The only way to restore the degraded estuarine habitats is by managing the levels of nitrogen entering the water, Howes said.

The good news is that after years of planning, in May the town approved funding for the first phase of its wastewater treatment plant. Once it is installed, the water quality will improve.

“The impact could be seen very fast,” Howes said. “You wouldn’t have to wait 20 years to see that happen.”

Although the treatment plant has been approved, it is still quite a ways from coming to fruition, and Howes estimates that it will take four to five years after its implementation for improvements to be seen.

Nitrogen management within Popponesset Bay has already begun with annual maintenance of the flow through the tidal inlet, the report states. The propagation of oysters within the system (which helps clear the nitrogen) and capping the town of Mashpee landfill are other steps that have been taken. Shellfish have also been deployed in Waquoit Bay. Those actions appeared to show some improvement, the report states, but more action is needed.

The town needs to increase nitrogen removal and transport, Howes said.

One solution is restoring cranberry bogs into freshwater wetlands and ponds that would intercept the nitrogen, he said.

‘Just stop it from getting worse’
Town Manager Rodney Collins asked what Howes would do if he were a policymaker. Howes said he would work to accelerate the wastewater treatment system and would consider taking more action on some of the “low-hanging fruit” that are quick temporary solutions, such as getting more shellfish in the bays.

The report found that although some algae blooms have been thought to impact shellfish, there was no evidence of shellfish loss in the recent blooms in the estuaries. The shellfish that are there are doing OK, he said, but the problem is the number of them. If you put enough shellfish in to help knock down the nitrogen in the bay and then harvest them to take the nitrogen out, it works. But the numbers need to grow, he said.

Just stop it from getting worse, Howes said.

Dredging would not help. It makes the bays deeper, he said, but it still has the same effect on the nutrients in the water.

“With dredging you scrape (the nutrients) off and then it builds up again,” he said. “It’s not a permanent solution.”

Some residents urged the board of selectmen to halt all building in Mashpee, especially the building of more septic systems.

“This is really bothersome and troublesome to hear,” Vice-chair David Weeden said in the meeting. He remembers when the bay used to take away nitrogen on its own instead of needing supplements with shellfish propagation.

Howes sounded slightly defeated in the meeting about the water quality and how long it took to get the wastewater treatment plant, which would greatly improve the water quality, approved.

“I moved here in 1997 when we talked about bringing in sewers,” he said in the meeting. “I hate to say it, but (the nitrogen is) in the ground now. And until you start taking it out somehow that’s going to be a problem.”

Contact Jessica Hill at jhill@capecodonline.com. Follow her on Twitter: @jess_hillyeah.

‘It’s totally gone’: Mashpee’s water quality at an all-time low, report finds – Cape Cod Times