Minutes for April 23, 2013 Meeting

Meeting Summary
Tuesday, April 23, 2013, 7:00-9:00 PM
The Hearthstone, 6720 East Green Lake Way N
Board Room

Recorder: Davis Patterson

Martin MullerKay EnglishLiz Graf-BrennenMarcia NormanSusan LevyKate BechererDillon RothSally AbellaBrian DeLucaBrian TothGaret MungerRob ZisetteEllen HewittJeannine Florance

Meeting comes to order with welcome and Introductions Garet Munger

The 2012 Water Quality Report for Green Lake, King County Department of Natural Resources and Parks – Sally Abella [sally.abella@kingcounty.gov]

  • Sally Abella presented summary of water quality since 2005, using May-October readings.
  • Mean trophic state indicators are used to track water quality in lakes. The trophic state indicators are calculated using clarity (Secchi disk), chlorophyll A, and phosphorus concentrations Eutrophic: very rich, low water clarity. Oligotrophic: clear, little algae, little chlorophyll, little phosphorus, and mesotrophic which indicates moderate levels of phosphorous, and algal growth.
  • From 2009 to present, these indicators have been in the mesotrophic range which indicates reasonably good water quality. Water quality in the lake has been pretty stable, and has even gotten a little clearer since the alum treatment:
    • Phosphorus has remained fairly constant since alum treatment.
    • Nitrogen has increased since alum treatment. Solid trend line.
    • Nitrogen/phosphorus ratio has increased over time, fairly solid trend. The lower the ratio, the better the cyanobacteria can thrive. Higher ratios lead to more competition with other organisms. The data show that the lake is getting more inhospitable to cyanobacteria over time.
  • The scums we’ve observed have been concentrated at the shoreline. The water offshore is clear. Not a classic bloom (extensive or whole lake coverage), but we still have to be vigilant about them.
  • Microcystin tends to be more of a chronic than acute toxin affecting liver function. Symptoms include throwing up or diarrhea, but it depends on how toxic the algae is. Anatoxin A is another toxin sometimes produced by cyanobacteria. It is a neurotoxin and can have an immediate effect. Toxicity is generally much higher inside the scum than in the clear water outside.
  • Some of the scums appear outside the May-October time frame. The choice of the May-October time frame is a cost-benefit consideration in an effort to test when most people and animals are using the lake in a way that would expose them.
  • Toxins seem to be associated with certain lakes—some lakes are quite rich and produce no toxins, while others less so but when they produce algae, they produce toxins. Green Lake seems to be of the latter variety.
  • Overall take-away: water quality is maintaining since the alum treatment. It seems that something else is causing scums in low concentrations, which accumulates by blowing up against different shores, which is what makes them hard to manage.
  • What management concerns are there? One year is not enough to change strategy. Sally does not expect to see real problems typically until mid to late summer. She thinks it would be good to develop educational signage. The warning signs need to explain better what’s going on—to use clear areas and avoid scum.
  • Rob does not agree with closure procedures—closing the entire lake when there are problems identified in just one part of the lake. Does FOGL want to change its strategy, to turn in samples only when we see more algae?
  • When you submit a sample to the state algae program, it becomes public record. The jurisdiction is alerted, it goes on the state web site, it’s publicly available, and the health department implements its 3-tiered management approach that includes posting caution, warning, or danger signs depending on cyanobacteria species and toxin levels. FOGL may want to be pretty sure the level is over 6 and consider the size of the scum before we submit.
  • The state has recommended the 3 types of signage. Jurisdictions don’t have to use them, but most do. The state operates on the paradigm of greatest risk. WA Depts. of Health and Ecology recognize the need for education signage and closing entire lakes.
  • Other states may have educational signs about bluegreen algae that could be posted year round rather than the sporadic posting of health department signs. We don’t have to reinvent the wheel. We can post signage on the web site and ask the Park Dept. to post signs (and not wait for the state).
  • A couple of persons from FOGL could work on this issue to find and adapt appropriate signs, post wherever we can (our web site), and discuss with Park Dept. about posting at the lake.
  • FOGL may wish to change its policy to avoid risking having the whole lake closed when it’s a small, localized issue. Rob is working on algae monitoring procedures. We will want to pass a draft of our criteria by Sally Abella and other experts. Sally suggests examining under microscope to see the composition and then decide how to monitor. Heat units, wind speed and direction are other factors to consider.
  • Small lakes data web site

Phytoplankton Impacts of Green Lake Alum Treatments – Rob Zisette [see link to PowerPoint on web site]

  • Rob reviewed history beginning 1916, when cyanobacteria complaints were first recorded, 1990 Improvement Plan, 1991 and 2004 alum treatments, analyses of post-treatment phosphorus loads, phytoplankton analysis over time
  • Alum treatments had significant impact on biomass and dominance of different types of phytoplankton. Dosage mattered: 2004 treatment had greater effects than 1991 and 2004 was three times the quantity of alum.
  • The group discussed how to bring the lake to the attention of the city when we do not have data that water quality is deteriorating. Because it’s a heavily used urban lake that needs to be managed, both Rob and Sally advocated for city planning and lake management planning to establish sources of alum treatment funding ahead of time. The best way to get the city to listen is to send a letter, requesting that the city begin to plan ahead, because the alum treatment is reaching its 10-year effective time frame. We do have more blue-green algae now than in 2008.
  • Sally disposes of phytoplankton samples after a year when she doesn’t have a budget to analyze them. The phytoplankton analysis costs about $90 per sample. She would be glad to give them to Maribeth Gibbons to analyze if FOGL could pay for the analysis. This may be something for FOGL to consider spending its fund on and doing fundraising if necessary to support this activity. For about $1100/year we could analyze the 12 collected samples to supplement other data. The decision to analyze 2013 phytoplankton samples would not need to be made until the end of the summer. FOGL will discuss funding the phytoplankton analysis at a future meeting.

The commentary and reports presented by Sally and Rob generated group discussion. There was no time at the end of the meeting to discuss the remaining agenda items:

  • Review of Earth Day at Green Lake
  • Park Department Report
  • Other Friends of Green Lake business

9:00 Adjourn