Green Lake Association: Caring For Big Green

people on pier
Photograph by Clearview Productions

If you’re looking for a relaxing day on the shore or an excitement-packed afternoon zipping across the water, Big Green Lake has something for everyone. The lake sees thousands of visitors each year and holds an important place in so many hearts and memories.

Green Lake’s physical properties add to its uniqueness. At 7 miles long, 2.5 miles wide, and 237 feet deep at its greatest depth, Big Green Lake certainly holds up to its name as Wisconsin’s deepest natural inland lake. However, such a big body of water comes with a big responsibility to take care of it, and that’s what the Green Lake Association (GLA) has been striving to do since 1951.

2021 marks the 70th anniversary since the GLA began. As a not-for-profit, member funded organization, the GLA has a singular focus on protecting and improving Green Lake’s water quality. On the surface, it’s difficult to see the challenges Green Lake is facing, but a deeper dive shows that the lake is struggling with low dissolved oxygen and increased phosphorus pollution, which leads to excess weed and algae growth—something no one wants to swim in!

Through membership dues and donations, the GLA funds and supports work that aims to protect, restore, and preserve the lake. Projects cover initiatives that remove and prevent invasive species, restore damaged streams, reduce phosphorus loading to the lake, promote agricultural conservation practices, facilitate scientific lake studies, and help educate the public on how to care for the lake at the heart of the community.

Photograph by Clearview Productions

Whether Green Lake is home year-round or just a favorite summer vacation spot, there are things everyone can do to help take care of this beloved natural resource:

  1. Become a GLA member: every membership supports important lake-protecting work.

  2. Prevent the spread of aquatic invasive species by following the AIS prevention steps:

    • Inspect all equipment before and after entering the lake.

    • Remove all plants, animals, and mud.

    • Drain all water from boats and equipment, even if the water looks clean, before and after visiting the lake.

    • Never move plants or live fish/animals from lake to lake.

  3. Clean up after pet waste: it contains phosphorus and bacteria that is harmful to water quality.

  4. Limit fertilizer on lawns and fields: it helps plants grow on land and will do the same in the water!

  5. Slow the flow of rainwater runoff at home by using rain barrels, installing rain gardens, and redirecting downspouts onto grass.

If interested in becoming a member or learning more about the Green Lake Association or events, visit or call (920) 294-6480.

Jennifer Fjelsted is the communication & project manager at Green Lake Association.

2021 Green Lake Association Events

June 19: Annual Meeting (Virtual)

August 7: Annual Gala (Virtual)

August 21: Land & Lake Family Field Day
10 a.m.-2 p.m.
Avalon Creek Farm
W1774 County Road K, Markesan, WI 53946