The Olympia and Tumwater city councils met with the Port of Olympia commissioners Tuesday for a study session about the future of Capitol Lake, as they wait to hear whether the state will fund the next step in the process for finding a solution for the marshy lake.
Representatives from consulting group Floyd Snider reviewed the options: keeping the 260-acre manmade reservoir as is, reverting the lake to its natural state as an estuary by opening the Fifth Avenue dam, or creating a hybrid version of both. No official action was taken at the study session, which was held at Olympia City Hall.
A committee of local, state and tribal stakeholders met several times in 2016 to identify goals and potential funding for Capitol Lake’s long-term management.
The next step is to secure $4 million from the Legislature to pay for an environmental impact statement, or EIS. If the state provides the money, the EIS could begin in late 2017 or early 2018 after a public bidding process.
The third phase of the project — design, permitting and construction — is expected to start in 2020 or 2021, after the EIS is completed. The third phase would last until 2025, according to estimates.
The lake is located at the mouth of the Deschutes River in downtown Olympia, and was created as a reflecting pool in 1951. The concrete Fifth Avenue dam divides Capitol Lake and Budd Inlet, and includes an 82-foot opening that control’s the lake’s water level.
However, the lake now holds about 60 percent less water as it turns into a marsh. Sediment from the river accumulates at about 35,000 cubic yards per year.
Possible hybrid options for Capitol Lake include a dual-basin option that includes a tidal estuary in the western portion along with a retaining wall that would create a 39-acre reflecting pool; a larger reflecting pool and freshwater input; and a “seasonal hybrid” that would establish a tidal estuary in the fall and winter, but maintain a reflecting pool by raising the water levels during spring and summer.
Other potential management options could incorporate more dredging, freshwater wetlands and park space in varying degrees.
Top priorities for Capitol Lake include aesthetics, sediment management, recreational opportunities, habitat restoration, water quality and flood management.
Sediment management is expected to be one of the costlier aspects because of the presence of the invasive New Zealand mud snail in Capitol Lake. The lake also is contaminated with phosphorus and fecal coliform bacteria.
The committee for the Capitol Lake effort includes representatives from the cities of Olympia and Tumwater, the Port of Olympia, Thurston County and the Squaxin Island Tribe. The group first met in January 2016 after the Legislature, in its 2015 budget, directed the Department of Enterprise Services to “make tangible progress” on the lake’s long-term management plan.