What is going on in Highland Lake and its watershed? May, 2017

posted Jun 11, 2017, 9:59 AM by Joseph Bickard

Have you noticed any change in the water clarity of Highland Lake these past few summers?  Water clarity is the depth to which sunlight penetrates below the surface. Water clarity, is a key indicator of water quality – the better the clarity, the healthier the lake

Unfortunately, monitoring and simple observations have revealed dramatic changes in historic clarity during the summers of 2014, 2015 and 2016. These are troubling trends you should be aware of.

But first some history:

Certified water quality monitors regularly check the clarity of Highland Lake with a device called a Secchi disc. The circular disc is distinctly marked with black and white alternating quarters and is lowered in to the lake until it disappears from sight. This is the point at which clarity is recorded. Maine lakes vary in Secchi disc clarity from a couple of meters to over ten meters. From 1980 to 2015, Highland Lake’s yearly mean clarity diminished from about seven meters to about five meters.

Regular monitoring of Highland Lake since the 1970’s shows a variable pattern of water clarity.  In the late 1970’s and early 1980’s water clarity readings were declining.  Concern about this trend led the Maine Department of Environment Protection (DEP) to place Highland Lake on the state’s list of “lakes most at risk from development” in the mid 1990’s.

The major culprit contributing to the reduced water clarity was an increasing level of phosphorous and nitrogen in the lake.  Phosphorous and nitrogen are nutrients that naturally occur in the soil.  When it rains, these nutrients that attach chemically to soil particles are carried from erosion sites to the lake by storm waters.  Watershed development, construction projects, camp roads, pet wastes, excess fertilizer use and septic systems also contribute nutrients to the lake.  By the early 1990’s, it was clear that Highland Lake was in trouble due to very high nutrient levels.

From 1997 to 2006, the Cumberland County Soil and Water Conservation District oversaw a  federal grant of over $600,000 that focused on countering the decline in water quality.  The entire lake community engaged in a focused program to reduce the nutrient flows.  Road associations instituted major projects to reduce excessive nutrient-rich runoff from camp roads into the lake.  Settling basins were installed to slow the flow of water from ditches and roadways.  Lakeside homeowners installed and upgraded vegetated buffers to reduce phosphorous runoff from lawns and rooftops.  Septic systems were upgraded.

All of this work resulted in the announcement in 2010 that Highland Lake had been removed from the list of “lakes most at risk.”  So all was good, right?

Trouble brewing in Highland Lake:

Through the ongoing efforts of people like Keith Williams and members of the Water Quality Committee, a key committee of the Highland Lake Association (HLA), monitors observed a very strange phenomenon occurring in the summer of 2014.  From mid-July into early August, water clarity suddenly decreased to under two meters.  The color of the water took on a greenish tint as it appeared the lake was experiencing a significant algae bloom. 

Then just as this phenomenon had occurred without warning, in mid-August, the green color suddenly disappeared, and the water clarity improved.  In 2015 and 2016, the same phenomenon occurred at almost exactly the same time as in 2014. 

Water clarity decline, especially a dramatic one, is never good news for a lake like ours. People get concerned.  Water quality is directly related to property values and enjoyment of the lake. 

So what was this sudden emergence of an unusual algae bloom?

Water quality monitors were very concerned and wondered what was happening in Highland Lake to cause it to suddenly turn green for 3 to 4 weeks during the summer?  The phenomenon was especially troublesome and perplexing because water quality testing prior to the annual algae outbreaks during the summers of 2014, 2015 and 2016 were superior with Secchi disk readings of 6 to 7 meters.  

Keith Williams and a team of scientists from the University of New Hampshire and the University of Southern Maine have determined that the lake turns green when populations of microscopic blue-green algae called Picoplankton explode.  This type of algae has only received the attention of New England freshwater scientists in recent years.  The tiny green balls must have nutrients to live and reproduce, so the challenge is to identify how they obtain their nutrients and what the sources are.  

Numerous questions remain unanswered:

-What is the specific identity of this unidentified algae?  We know that the algae is a form of Picoplankton.  Picoplankton is a cyanobacteria which the Maine DEP says are “microscopic organisms that are actually bacteria. They are commonly called blue-green algae because dense growths can turn the water any color from blue green to brownish-green. These algae are a natural part of lake ecology, but high nutrient levels in water can cause heavy growths (blooms), especially during warm weather.

-Why does this phenomenon only last for about 3 to 4 weeks each year?  More study needs to be done to answer this question.

-Can the same clean-up efforts conducted in the 1990’s and 2000’s help this situation now? In other words, what can we do about this recurring algae bloom?  What do we need to do to prevent it

Why hasn’t the Highland Lake Association been more vocal about this threat?

The algae  bloom has proven to be a complex problem. When the lake first turned its greenish tint in 2014, there was curiosity among water quality monitors, but when the color disappeared and the clarity returned to normal, it seemed this might have been an anomaly. 

When the algae bloom reappeared in 2015, at the same time as the previous summer, there was a whole new level of concern. 

By the spring of 2016, the water quality team was armed with two years of data and became increasingly aggressive in its monitoring.  During 2016, the team conducted over 40 observations of water clarity, nutrient levels and dissolved oxygen and sent over 130 water samples to the laboratory at the University of New Hampshire.  They conferred with regional agencies and academic researchers for insight and assistance. As monitoring in 2016 became more intensive, the third appearance of the bloom confirmed we were facing a persistent and serious problem. 

New challenges demand new strategies:

Based on highly-focused work and experience, the HLA determined that it needed to look at the algae bloom phenomenon with a new perspective.  There were two major changes that we had to address:

1.    Funding was needed to conduct the in-depth analysis required to identify the algae.  Hence, the Association applied for and was granted $4,000 from the Town of Windham to help fund detailed scientific analysis.  

2.    We needed to improve communications with the residents of the lake’s watershed.  A more effective communication strategy was essential for long-term success. 

Now, armed with the municipal grant along with an additional $2,000 from the general fund of the Highland Lake Association, water quality monitors are committed to following an intense monitoring schedule in an effort to figure out what is going on in time to avert more serious and perhaps permanent damage.

The Association is on a mission to discover the exact type of algae that appears in mid-summer, and is committed to improving its communications with the residents of the Highland Lake Watershed about what we all can do to restore our water quality.  You will hear from us through a range of communication media to better inform you and your neighbors about this important effort.

In conclusion, a challenge to you:

As residents and landowners of Highland Lake, you are the Association’s most important partners. We are dedicated to developing a multi-faceted action plan that includes research, outreach, education, and land use surveys.  Ultimately, it may be necessary to upgrade land use standards to protect the lake and the enormous emotional and economic investments we all have in it. Please consider a special gift to the Highland Lake Campaign to fuel the work. Let’s work together to raise the resources to solve this dangerous mystery.  We cannot succeed without your help.