The Washington State Department of Enterprise Services (Enterprise Services) has conducted an environmental review process under the State Environmental Policy Act (SEPA) for the Capitol Lake – Deschutes Estuary Long-Term Management Project. The Final Environmental Impact Statement (EIS) was published on October 31, 2022.

The Estuary Alternative has been identified as the Preferred Alternative for long-term management of the Capitol Lake – Deschutes Estuary.

What is the Capitol Lake – Deschutes Estuary?

Historically, what is now known as Capitol Lake was part of the Deschutes Estuary, where freshwater from the Deschutes River would mix with saltwater from Budd Inlet over expansive tideflats. The Deschutes Estuary has long-standing cultural and spiritual significance to local tribes, particularly the Squaxin Island Tribe. The Squaxin Island Tribe considers the people and land of Deschutes Estuary as Steh-Chass.

Between 1949 and 1951, a dam was constructed at 5th Avenue. Without the tidal exchange, the area was transformed into a freshwater lake, fed primarily by the Deschutes River. The waterbody was renamed Capitol Lake. Capitol Lake is the 260-acre waterbody located on the Washington State Capitol Campus, adjacent to downtown Olympia, at the base of Puget Sound. Capitol Lake was designed as part of the Washington State Capitol Campus, and it quickly became an important visual and recreational resource to the community.

What problem is this project seeking to resolve?

An estimated 35,000 cubic yards of sediment are transported by the Deschutes River (and Percival Creek) into the Capitol Lake Basin each year, shallowing the lake and resulting in conditions that are visibly altered. Since construction of the 5th Avenue Dam, sediment accumulation has reached up to 13 feet thick in some areas. Water quality monitoring began in the 1970s in response to excessive growth of aquatic plants, dense algal mats, and reduced water clarity, which are caused by high nutrient levels in Capitol Lake. In 1985, the Capitol Lake swimming beach operated by the City of Olympia was formally closed because of high bacteria levels, following years of intermittent closures due to water quality conditions near the swimming area, including lack of water clarity. Beginning in the late 1980s, management strategies were implemented to address aquatic invasive species. There are now more than a dozen different plant and animal aquatic invasive species in Capitol Lake. In 2009, the presence of the invasive New Zealand mudsnail resulted in official closure to all public uses.

Many of these environmental conditions persist today and active use of the waterbody continues to be restricted. The long-term management project is needed to address the diminished beneficial uses of the waterbody, caused by accumulating sediment, historically poor water quality, algal blooms, and invasive plant and animal species.

What are the project goals?

In 2016, Enterprise Services, in coordination with the Squaxin Island Tribe, governmental and agency partners, and the community, identified four primary goals for long-term management of the Capitol Lake – Deschutes Estuary that should be satisfied by any long-term management alternative.

The goals were established during a collaborative process, referred to as Phase 1 of the Long-Term Management Project. There is broad agreement that a long-term management project must be implemented to achieve these goals and improve existing conditions in the Project Area. 

Project goals: improve water quality, improve ecological functions, manage sediment, and enhance community use.

The Capitol Lake – Deschutes Estuary Long-Term Management Project seeks to identify an environmentally and economically sustainable management alternative that will improve environmental conditions and enhance community use of the resource.

What is the Project Area?

The Project Area includes the 260-acre Capitol Lake that is managed by Enterprise Services, and it extends to the northern point of West Bay of Budd Inlet. The parks and public space adjoining Capitol Lake and within the jurisdiction of Enterprise Services are also included in the Project Area.

The Project Area does not extend upstream of Tumwater Falls into the Deschutes River (south) because that area would not be directly affected by the Capitol Lake – Deschutes Estuary Long-Term Management Project.

An aerial map of the project area that also shows the difference between Capitol Lake and the Capitol Lake - Deschutes Estuary. Capitol Lake is the waterbody between Tumwater Falls and the 5th Avenue Dam, and the Capitol Lake - Deschutes Estuary extends into Budd Inlet. 
    The map also shows the area within Enterprise Services jurisdiction, which is Capitol Lake and many of the adjacent parks, as well as the area outside of Enterprise Services jurisdiction, which is the area north of the 5th Avenue Dam.