Improving water quality in ponds starting to gain momentum says panel at regional summit
The health of local ponds or lakes is something Cape Cod residents and visitors take more personally than they do marine water bodies, Andrew Gottlieb, executive director of the Association to Preserve Cape Cod, said.
"People have a much more emotional, direct relationship … They talk about going to my pond," observed Gottlieb speaking at an online forum on existing water quality in freshwater ponds and lakes Tuesday afternoon. The forum was part of this year's OneCape Summit, hosted by the Cape Cod Commission on Monday and Tuesday.
"There is a chance to harness a motivated public to stop pollution and improve water quality," Gottlieb said.
Freshwater ponds located so close to the ocean is a unique feature of Cape Cod, explained Sophia Fox, an aquatic ecologist with the Cape Cod National Seashore. In her presentation Tuesday, Fox said the state "Natural Heritage Program designated Cape Cod ponds and lakes as ecological, recreational and aesthetic treasures for their biodiversity and rare species."
But the personal relationship Cape Codders have with "their" ponds and lakes doesn't mean we've treated the Cape's approximately 1,000 lakes and ponds any better than the coastal bays, rivers and inlets. They are subject to pollution from excess nutrients such as nitrogen and phosphorous from septic systems, road and stormwater runoff, and lawn fertilizers that feed algal and other vegetative blooms that can suck life-giving oxygen out of the water and/or produce harmful toxins.
The nutrients can also feed the explosive growth of invasive plant species that can outcompete the native plants.
While much of the region's wastewater cleanup effort has been directed at the marine environment, water quality researchers and experts have been hearing from many who say "What about the ponds?" Tim Pasakarnis, Cape Cod Commission Water Resources Analyst, said.
"There's been continued interest in them that whole time," he said, and that led to a growing number of research and remediation efforts aimed at assessing trends in pond health and repairing the damage.
Cyanobacteria a growing problem in Cape Cod ponds and lakes
With toxic algal blooms appearing to be increasing in number and duration, and the documented stress of global warming on lakes and ponds, these fragile water bodies have also caught the attention of municipalities. Improving their health is on a much shorter timeline than their saltwater counterparts.
"We have added staff (to the ponds and lakes program) because people aren't going to wait 30 years to address a cyanobacterial outbreak on their pond," Barnstable Town Manager Mark Ells said.
The problem is that while a lot of data has been collected on ponds over the years, it barely scratches the surface. There is water quality monitoring to varying degrees on 230 of the Cape's ponds, including 135 that are being monitored by pond associations in 12 towns. The APCC monitors 144 ponds for potentially toxic cyanobacteria on a biweekly basis.
This year, the Cape Cod Commission will update its pond and lake atlas for the first time since it was published in 2003. They located and identified over 996 ponds covering over 11,000 acres and ranging in size from an acre to over 740 acres.
The new atlas will compare new data to the baseline data from 2001 that was used in the 2003 version. It is part of the commission's "Freshwater Initiative" to collect data, improve monitoring and planning and define the way forward for the region to improve freshwater water quality, Commission Deputy Director Erin Perry said
The commission also created new tools to help policymakers and the public to visualize what is going on with their local ponds and lakes. A new data portal, for instance, will allow users to find a pond or lake and click through layers of monitoring data, trends, and potential or existing stressors.
National Seashore ponds are warmer than in the 1970s due to climate change
The Cape Cod National Seashore has one of the oldest records of data on pond health in the country, said Fox, with data on 20 park ponds collected back into the 1970s. The changes they've seen include: pond waters becoming significantly warmer as the atmosphere has warmed, approximately 5 degrees F, but some warmed by as much as 10 degrees; and pond stratification, where waters form layers according to temperature and water density, has intensified in strength and duration. Both these conditions make it tougher for pond inhabitants to survive, she said.
Plus, increased use by locals and visitors resulted in more erosion and native vegetation that can stabilize pond shorelines getting trampled.
The park is engaged, along with partners such as towns and the APCC, in research that includes a pond plankton inventory, participation in a nationwide harmful algal bloom project, APCC's cyanobacterial project, and a review of their water quality data to find trends. They have also been working on mitigating and repairing erosion pathways by limiting visitor access and new plantings.
But data collection to determine trends and find solutions is desperately needed, researchers and water quality experts said. One innovative study from NOAA uses satellites to analyze reflectivity from the Cape's lakes and ponds to estimate their color and transparency, an indicator that they may be impaired by contaminants that drive increased plant growth.
Thus far, they have collected data on 400 Cape freshwater ponds and are looking for volunteers to collect on-site water transparency readings to truth test their data, Nicole Bartlett, NOAA management analyst, said.
APCC'S water sampling and analysis of 144 ponds for toxic cyanobacteria in 15 Cape towns, found 42% of those ponds had unacceptable levels in 2020. So far this year, 31 Cape ponds reached the highest tier cyanobacterial levels requiring closure, Gottlieb said.
Still, the data is sparse enough and the conditions that result in bacterial growth vary from one pond to the next so that it's still hard to make definitive findings on trends in water quality in ponds and lakes, Gottlieb said.
"The take-home is that water quality in ponds is highly variable. We know enough to know we have a bigger problem than quantified," he said. "We need more data to say which ponds are at risk and we need better (pond) management."
