Water Quality

Big Rock, Watchic Lake

Big Rock, Watchic Lake

By most any measures, the quality of Watchic Lake is very good. A clean lake benefits everyone. Not only does it create excellent recreational opportunities, it also ensures a healthy environment for wildlife, and helps maintain shoreline property values.

One way to measure water quality is to use a Secchi Disk, which is an instrument that measures clarity. It is lowered into the water and the depth at which the disk can no longer be seen is recorded as a measurement of lake clarity. Secchi Disk readings are taken regularly at Watchic Lake and are in the 4 to 4.5 meter range (meaning transparency down to about  15 – 16 feet).

The Watchic Lake Association (WLA) is dedicated to monitoring and improving the quality of Watchic Lake. The Association does regular lake quality readings,  manages the dam to ensure appropriate water levels, directs major remediation projects (such as the Paine Neighborhood project), coordinates the LakeSmart program, and works with property owners on an ad hoc basis to address quality issues.

It is up to all of us to protect this lake. While we own the property currently, we are but stewards for now; the future of the lake is in our hands.

  • Please consult Standish Town Hall and/or the Department of Environmental Protection for information on any changes to your property.
  • Expansion, tree removal, and drainage changes can adversely affect water quality and are all closely monitored.
  • Landscaping products that were acceptable in an urban environment may create problems in a shore front location. Phosphorous from runoff is our worst enemy.

2019 Water Quality Summer Update

The water quality committee has been out on the lake about 10 times this season checking the water quality.  You may have noticed that the water clarity is lower than usual. Water clarity can change for several reasons. This year one big influencer of lower clarity is our wet spring and the resulting increase in nutrients (especially phosphorus) that was washed into the lake. We measure clarity using a Secchi disk. Figure 1 belows shows the readings this year and the historical average for 2016-2018.

Temperature and Dissolved Oxygen: As expected, the temperature in the lake has stratified, where the top is warm (this area is where we see most of the activity (e.g. algae growth) while the bottom remains cool.   The DO pattern over time is also what we’ve seen in recent years.  The lack of oxygen at the bottom of the lake will restrict fish species that like colder water, but may also cause phosphorus stored at the bottom of the lake to be released into the lake.  This phosphorus can fuel further algae growth. We will start measuring and tracking the phosphorus levels at the bottom of the lake this month to monitor for changes. Figure 2 shows the water temperature and dissolved oxygen (DO) at 1-meter intervals from the top of the lake down.

The Water Quality team has documented a series of metaphyton algal blooms. Metaphyton is cotton candy-like algae that usually floats near the top of the shallow water but can get stuck in lake vegetation and accumulate. It is not harmful, but very unpleasant to swim in. This spring large accumulations of metaphyton were reported just north of the Kiwanis Beach, in the mouth of Page Brook, and near the mouth of Paine Brook. We will continue to monitor the areas and the rest of the lake for metaphyton.

Metaphyton locations in green.

These algae, like most others, are fueled by extra nutrients entering the lake, most likely from storm run-off or septic tank issues. Other things driving recent observations include:

  • Warmer temperatures for longer periods of time:
    • Early Ice-Out/late Ice-In dates and the resulting longer growing season for algae in the lake.
    • Thinner ice allowing more light into the lakes so plants and algae may not die during the winter.
  • More severe weather events (rain and droughts) resulting in more nutrients from storm run-off entering the lakes and streams.

The team has also attended the annual Lake Stewards of Maine Lake Monitoring Conference to learn more about to best monitor Watchic water quality. From the conference, they learned that what we are observing on our lake is typical for lakes in Maine.  The lakes are in a delicate balance with their environment and climate change is definitely having and will continue to have a major impact on our lake.

Click or touch here to read the full mid-summer water quality update.

2018 Water Quality Report Completed

We have just completed our 2018 water quality report for Watchic Lake. The data used in this report comes from readings done by FB Environmental and WLA volunteers. All data has been certified and has been submitted to Maine VLMP. This report includes the same rich set of testing we did in 2016 and 2017. The report also includes a summary of water quality metrics over the past three years.

In summary, the report states that while water quality is good today, Watchic Lake remains at long term risk due the increasing human activities around the lake. The main concern at Watchic Lake is the low dissolved oxygen in the bottom waters. Low oxygen conditions can release nutrients (phosphorus) attached to sediments on the lake bottom. Adding phosphorus to the lake can stimulate excessive algal growth. High phosphorus in both of the inlet streams suggests that there is also phosphorus entering the lake from the surrounding watershed. Both low oxygen and high productivity can be dangerous for aquatic organisms and fish. Click or touch here to read the 2018 Watchic Lake Water Quality Report.

The message is clear – as property owners and interested stakeholders, we must work to address increasing runoff into the lake to improve oxygen levels, avoid algal blooms and excessive plant growth, and retain a healthy habitat for fish, loons, and other wildlife.

The Lake

Trophic state indicators (total phosphorus, chlorophyll-a, and water clarity) showed that water quality in Watchic Lake remains overall very good.

However, low oxygen (< 5 ppm) in the summer months continues to make the bottom waters of the lake unsuitable habitat for aquatic life that have historically been an important natural and recreational asset to the lake (e.g., smelt). This oxygen depletion is caused by the decomposition of organic matter (i.e., dead algae and plant matter) that has settled on the lake bottom. While it is difficult to remedy what has already been done, the best way to combat future worsening of oxygen depletion in Watchic Lake is to limit the amount of nutrient input to the lake and streams.

pH in the lake is within the acceptable range for aquatic life, but low alkalinity is classified as highly sensitive, meaning that the lake is not well-buffered against environmental factors that may cause significant changes in pH.

The Tributaries – Page (northern end) and Paine (southern end) Brooks

Both streams exhibited low fecal indicator bacteria (E. coli) counts.

Nutrients (nitrogen and/or phosphorus) were elevated in both streams, indicating human pollution from septic systems, fertilizers, surface runoff, etc. Both streams experienced low oxygen and low pH, which can negatively impact the growth and reproductive health of aquatic life. Low oxygen (particularly in Page Brook) and low pH can be the result of natural or human sources, but are likely from human sources considering the elevated nutrient levels measured in the streams.

We thank all our members, sponsors, and especially the Town of Standish, for supporting this study.

Use the Contact Us page should you have questions.

2017 Water Quality Report Available

We have completed our 2017 water quality report for Watchic Lake. The data used in this report comes from readings done by FB Environmental and WLA volunteers. All data has been certified and has been submitted to Maine VLMP. This report includes the same rich set of testing we did in 2016. The report includes a very useful glossary of terms and some great educational material.

In summary, the report states that while water quality is good today, Watchic Lake remains at long term risk due the increasing human activities around the lake which can increase the amount and transport of harmful pollutants and foreign materials into the lake and its streams. Catastrophic events such as mega-storms put roads, drainages, and septic systems at risk of introducing toxic runoff.

The message is clear – as property owners and interested stakeholders, we must work to address increasing runoff into the lake to improve oxygen levels, avoid algal blooms and excessive plant growth, and retain a healthy habitat for fish, loons, and other wildlife.

The Lake

Watchic Lake 2017 Water Quality Report ChartTrophic state indicators (total phosphorus, chlorophyll-a, and water clarity) showed that water quality in Watchic Lake is overall very good.

However, low oxygen (< 5 ppm) in the summer months is making 14-32% of lake volume a less suitable habitat for aquatic life that have historically been an important asset to the lake (e.g., smelt). This oxygen depletion is caused by the decomposition of organic matter (i.e., dead algae and plant matter) that has settled on the lake bottom. Low oxygen can cause a chemical reaction that releases phosphorus back into the water column to fuel more algae growth (thus generating a positive feedback to eutrophication). The best way to combat future worsening of oxygen depletion in Watchic Lake is to limit the amount of runoff into the lake and streams.

The Tributaries – Page (northern end) and Paine (southern end) Brooks

Nutrients (nitrogen and/or phosphorus) were elevated in both streams, indicating human pollution from septic systems, fertilizers, surface runoff, etc. Paine Brook showed higher nitrogen, while Page Brook showed higher phosphorus. Consistent with these elevated levels, both streams experienced low oxygen and low pH.  Although Paine Brook had higher average fecal indicator bacteria (E. coli) counts than Page Brook, both streams exhibited low readings overall. An analysis of land use may help determine differences in nutrient sources draining into each stream.

As property owners and interested stakeholders, we must continue to work to address these risks, in order to avoid algal blooms, low oxygen levels, excessive plant growth, and uncontrolled shoreline erosion.

We thank all our members, sponsors, and especially the Town of Standish, for supporting this study.

Please read the full report here and use the Contact Us page should you have questions.

Earlier Water Quality Reports