Monthly Archive: January 2017

Secchi Depth: 4.5 m / 14.8 ft
Water Temp: 5.0 C / 41.0 F

After over two weeks of ice cover, the lake is ice-free. 2.3 inches (60 mm) of rain January 17/18 brought the lake up ~2 inches. The lake is returning to its lower winter level.

Water goes from green to blue after the alum treatment

The treatment was monitored on a full-time basis in accordance with the water quality monitoring plan and permit requirements. The treatment increased water transparency (Secchi depth) from 9 to 19 feet and changed the color from green to blue, and had no effect on the lake pH or dissolved oxygen concentrations.

The treatment boat spread alum and buffer evenly over the entire lake 12 hours a day for 6 days.

Alum and buffer were trucked to the lake from as far away as Edmonton, Alberta, and stored in separate tanks contained in a parking lot near the Small Craft Center. Each chemical was pumped through hoses from the storage tank to tanks on the treatment boat in the lake. A ramp was constructed over the hoses to allow use of the foot path throughout the entire treatment period.

A tanker truck filled storage tanks on the shore.

Alum and buffer were injected into the water surface through paired hoses from tanks on the treatment boat. The injected chemicals formed small particles that settled to the lake bottom, removing phosphorus and algae from the water column as they settled. The settled aluminum binds to phosphorus in the bottom sediments to reduce the internal release of phosphorus from the sediments to the water, and limit the growth of algae and toxic cyanobacteria in the lake during the summer. The treatment goal is to prevent future closures of the lake to recreational uses due to toxic cyanobacteria for up to 10 years. The treatment plan and more information can be found on the project website.

Algal scum on the lake, before the treatment.

Previous lake-wide alum applications in 1991 and 2004 effectively limited algae blooms and improved water quality. The alum treatment is expected to be effective for up to 10 years. The alum treatment plan was developed as part of the 2016 Green Lake Phosphorous Management Plan.

If you have additional questions about the project please contact Chris Mueller, Seattle Parks and Recreation project manager at chris.mueller@seattle.gov or 206-684-0998.

Click image to see alum treatment coverage.

Green Lake Stewards are on the job in good weather or bad, year round, to remove invasive species of English Ivy and blackberries that proliferate around the lake.  In November 2016, they planted 150 native plants on the west side of the lake.  Here is their story, told by Garet Munger and Andrea Watts.

by Garet Munger and Andrea Watts

Green Lake is the beloved lake in the heart of Seattle’s Green Lake neighborhood that people from all over the city come to visit. On any given day, you can find runners running laps along its outer path, families with strollers, and fisherman fishing from the lake’s edge. Unfortunately, blackberry and English ivy have invaded the shoreline habitat around the lake. Green Lake Stewards is a small but growing group of volunteers who are dedicated to maintaining and enhancing the natural areas around the lake by removing invasive plants where they are coming to dominate the shoreline habitat. Our intention is that our work to control the non-native plants will help to give native plants a chance at the lake.

Green Lake Stewards Hard at Work

We work in partnership with the Seattle Parks and Green Seattle Partnership, and since July 2015, we have hosted monthly work parties to remove the invasive plant species, such as Himalayan and evergreen blackberry and English ivy, from around the lake. Removing these invasive plants provides more growing space for native plants and creates a healthier ecosystem. In November of 2016, we planted 150 native shrubs and trees along the west side of the lake north of the small craft center. Work parties are regularly scheduled on the third Saturday of each month.  Check the Friends of Green Lake calendar for time and place.

Contact Rob Hutcheson at hutcheson@seanet.com with questions or to volunteer.

Room opens for socializing and conversation at 6:45 PM

• Introductions

• Review of projects* recommended to Parks Department in 2016 for Green Lake Park

• Prioritizing projects for FOGL’s action in 2017

• Conversations on current Green Lake concerns: Parks District budget, Community Center plans and Evans Pool updates, etc.

• Treasurer’s Report and Webmasters Report

• We need a President, Vice-President, and Treasurer

• Adjourn

*The To Do List was drawn up by the Friends of Green Lake and submitted to Seattle Parks and Recreation Department in July.  It includes 24 items such as Improving Path Safety, Remodeling West Beach Changing Rooms, and Removing Trees in Shoreline Wall.  For the complete list visit https://friendsofgreenlake.org/wp-content/uploads/2016/07/2016-July-To-Do-List.pdf

Next FOGL meeting will be April 25th. (We are meeting quarterly, or as needed, in 2017.)

Thanks to the Hearthstone for hosting our meeting.

Friends of Green Lake (FOGL) is a non-profit group in Seattle, Washington, whose mission is to ensure a healthy Green Lake for wildlife and recreation, for today and tomorrow.