WINDHAM — A group of about 35 volunteers and technical support staff sacrificed most of their Saturday last week to help pinpoint possible sources of erosion in Highland Lake, which could be playing a role in the lake’s mysterious bloom.

The Highland Lake Association – in partnership with the Maine Department of Environmental Protection, Cumberland County Soil and Water Conservation District and the towns of Windham and Falmouth – organized a May 19 watershed survey aimed at locating potential sources of erosion around the 623-acre lake and its surrounding watershed that includes parts of Windham, Falmouth and Westbrook.

“It’s all about identifying erosion sites,” said lake association President Rosie Hartzler, who added that the survey was about cooperation among watershed property owners, not about taking any enforcement action.

For the last four summers, Highland Lake has experienced a temporary but sharp decline in water quality over a period of several weeks. Experts believe the culprit to be a form of cyanobacteria or blue-green algae – but questions still loom as to the cause of that algal bloom.

One likely factor is the presence of excess nutrients such as phosphorus, which could be getting into the lake via erosion sites.  

“We’re interested in that erosion because of nutrient phosphorus,” Heather True of Cumberland County Soil and Water Conservation District told watershed survey participants during a training session Saturday morning.

The survey split the watershed into eight sectors, and teams of several volunteers were paired with technical leaders and tasked with finding potential erosion sites within those sectors.

The final result will be a survey like one recently produced for Forest Lake.

Before heading out Saturday morning, participants were given survey training that included an overview from Wendy Garland of the Maine Department of Environmental Protection.

Garland outlined potential sources of erosion into lakes – including bare soil, construction sites, private roads and driveways – and provided some examples of techniques to mitigate runoff into water bodies.

True gave an overview of what exactly the surveyors would be looking for and recording in order to pinpoint erosion sites, including what the soil erosion problem might be, where it’s located, and how it could be addressed based on the measures Garland outlined.

John McClaine, an environmental specialist with MDEP, emphasized that the goal of the survey is to identify not just erosion sites in the watershed, but those with the greatest potential to add nutrients to the lake.

Hartzler said that the lake association used its own database of properties in the watershed and tax records from each town to send out approximately 1,300 letters in an attempt to reach all watershed property owners.

Hartzler said that a total of 29 properties opted out of the survey ahead of time, and she didn’t think there were “that many” people who opted out in person Saturday.

McClaine also urged participants not to be die-hards in trying to survey any properties marked no trespassing or posted, and to respect people who opt out.

“We’re going to respect private property rights,” McClaine told the group.

Hartzler said there were “isolated situations” over the course of the day in which property owners didn’t want their land included in the survey, but thought “overall, it went really well.”

“Our priority was to survey all of the shoreline properties,” Hartzler said, also mentioning properties along any major streams that feed into the lake.

One property that has played a notable role in the lake health and moratorium discussion – a 38-acre parcel on the lake in Windham owned by Chase Custom Homes & Finance – will be included in the survey.

The lake association raised concerns about a proposed manufactured housing park and mixed-use development on the site as part of a successfully push for the town of Windham to pass a development moratorium for its portion of the Highland Lake watershed.

Though developer John Chase had initially alluded to the possibility of legal action last year, his company later hired former Windham code enforcement director Heather McNally, who indicated a willingness to to open “some more dialogue” with the lake association.

Hartzler said that McNally met members of the watershed survey team at the property Saturday and walked around with them, which Hartzler described as a “totally positive experience.”

McClaine provided an approximate time line for the survey results Saturday morning, noting that there would need to be follow-up work throughout the summer to try to complete all of the survey sectors around the watershed. He anticipated a draft report in October and final report distribution in December.

Hartzler said this week that she expects to be able to share “some preliminary results” of the survey at the lake association’s annual meeting on July 19.

“It’s quite a process from here on out,” she added.

Matt Junker can be reached at 781-3661 ext. 123 or mjunker@keepmecurrent.com. Follow him on Twitter: @MattJunker.

Volunteers for the May 19 Highland Lake watershed survey attended a training session at the Cornerstone Church in Windham before heading out in search of potential erosion sites.

The watershed survey of Highland Lake will include eight different sectors around the lake.