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Frequently Asked Questions

Capitol Lake is a 260-acre man-made reservoir in Olympia and Tumwater, Washington. The Department of Enterprise Services manages the lake as part of the Capitol Campus.

The lake was created in 1951 when the state constructed an earthen dam and concrete spillway at 5th Avenue in Olympia. The same year the state built Deschutes Parkway, a nearly two-mile long road that parallels the western shore of the lake.

The original idea for creating a lake came from the 1911 master plan for the design of the Legislative (Capitol) Building and the Capitol Campus. The plan called for the “submerging of the mud flats by the creation of an artificial lake through the construction of a dam, bulkhead or spillway near the Fourth Avenue Bridge.” The goal was to create a reflecting pool for the Capitol.

When the final approval was given for construction of the dam, following World War II, a new reason emerged for creating the lake. It would help revitalize a part of the community along the shores of Budd Inlet that was in a state of urban decay.

In 1997, a committee made up of state, local and tribal government officials was formed to study lake management issues. This group met for many years, delivering a recommendation in 2009 on the future of the basin.

Long-term management planning for Capitol Lake/Lower Deschutes Watershed

Why was long-term management planning resumed in 2016, and who participated?

The Washington State Legislature, through proviso in the capital budget for the 2015–17 biennium, directed the Department of Enterprise Services (DES) to “make tangible progress on reaching broad agreement on a long-term plan” for the Capitol Lake/Lower Deschutes Watershed. Work throughout calendar year 2016 is referred to as Phase 1 and culminated in submission of a report to the Legislature in response to the proviso. Phase 1 laid the groundwork for Phase 2 (project-specific Environmental Impact Statement (EIS)) and Phase 3 (design, permitting, and construction of a long-term management option).

The work occurred in collaboration with the community, governmental entities, and coordinating state agencies, many of which also participated in earlier efforts.

Representatives from the following entities comprised an Executive Work Group, a Technical Committee (to review natural resource issues), and a Funding and Governance Committee (to consider future shared funding and governance).

  • Squaxin Island Tribe
  • City of Olympia
  • City of Tumwater
  • Thurston County
  • Port of Olympia
  • Washington State Department of Natural Resources
  • Washington State Department of Ecology
  • Washington State Department of Fish and Wildlife

What are the goals for long-term management of Capitol Lake/Lower Deschutes Watershed?

As part of the Phase 1 process in 2016, the stakeholders and community identified common goals that should be satisfied by any long-term management option that would be considered for implementation. A long-term management project should identify and implement an environmentally and economically sustainable watershed approach that:

  • Improves water quality
  • Enhances ecological functions
  • Manages sediment accumulation and future deposition
  • Restores community use of the resource

What are the primary steps in an Environmental Impact Statement (EIS)?

The primary steps of an EIS include a scoping period, a technical evaluation and alternatives analysis that compares the benefits and impacts of the range of reasonable options, issuance of a Draft EIS for public comment, and a Final EIS. These steps are outlined in the flowchart below, with a description of activities associated with each step.

More information about the EIS process is available on the Washington State Department of Ecology's website.

What are the opportunities for stakeholder and community involvement in the Environmental Impact Statement (EIS)?

Continued involvement of stakeholder groups and the community will be an essential part of the EIS process. DES expects to engage the community through design charrettes, public meetings, and other similar forums.

DES will continue to engage with the Executive Work Group, Technical Committee, and Funding and Governance Committee, similar to the approach taken in Phase 1. These entities have also committed to staying actively engaged in the project and have a strong interest in participating to ensure a successful environmental review process.

The community will be encouraged to participate in the EIS at milestones defined in the State Environmental Policy Act (SEPA) as well as through additional opportunities.

The EIS includes opportunities for the community and stakeholders to comment at key points in the process that can directly influence the EIS and its outcome:

  • Scope of the review (during scoping).
  • Analysis of alternatives (once the Draft EIS is issued).

Comments are also accepted on the Final EIS.

Would sediment management be evaluated as part of the Environmental Impact Statement (EIS) and what else would be evaluated?

Yes, sediment transport and deposition will be evaluated as part of the EIS. The EIS will also evaluate benefits and impacts to other areas of the natural and built environment, such as water resources, biological resources, cultural and historic resources, visual quality, land use, and other disciplines identified during the scoping process.

The rest of this paragraph is an example (focused on sediment management) of the process to evaluate these areas of the environment. As part of the EIS process, a technical expert would evaluate sediment transport and the locations of deposition within lower Budd Inlet under the “open system” long-term management options (options without the 5th Avenue Dam). The technical expert would use a sediment transport model that would be built specifically for this project or the expert could update and use the existing U.S. Geological Survey-model that was built in 2006 for the Deschutes Estuary Feasibility Study. During the evaluation, the technical expert would identify potential impacts to operational and recreational uses downstream and within Budd Inlet. After the anticipated location and extent of potential impacts is better understood, DES would work directly with the affected stakeholders to develop mitigation measures that would avoid, reduce, or mitigate the impacts. The impacts from sediment transport and deposition could be mitigated in a variety of ways, ranging from the volume of initial dredging, to design and installation of sediment management structures, to frequency and location of maintenance dredging. This process to understand and identify potential impacts, develop mitigation for the impacts, and compare the impacts across options is a key part of the EIS.

Would economic benefits and impacts be evaluated as part of the Environmental Impact Statement (EIS)?

DES has made an early commitment to include economics as a discipline for review in the EIS, if Phase 2 is fully funded. DES heard from a range of stakeholders that economic impacts and benefits of the options evaluated in the EIS should be studied (for example, potential impacts to the marinas from sediment or impacts to downtown businesses and tourism). Though an economic analysis is not a required component of an EIS, DES understands that it would strengthen the process.

What is the cost of construction and maintenance for the long-term management options?

As part of the Deschutes Estuary Feasibility Study (2007) and the Capitol Lake Alternatives Analysis (2009), conceptual costs (or “order of magnitude” costs) were developed for the Restored Estuary and Dual-Basin (or “Hybrid Option). However, since that time, a number of conditions have changed that would significantly affect the cost estimates.

The EIS is expected to include an informed cost estimate for each option evaluated.

It is most appropriate to develop cost estimates when more detailed designs are available and existing data gaps are filled by technical analyses (and not sooner). Those informed cost estimates could then be used for a number of agency decisions, including: development of design components, sustainability of the options or opportunity to incorporate sustainable design components, preference between options, construction and maintenance approach, and many other items.

How long does it take to complete an Environmental Impact Statement (EIS)?

DES anticipates that an EIS of this size and complexity will require about 3 years to complete.

How much will an EIS cost?

The current funding request for Phase 2 is $4.9 million, which is comparable to the cost of other EISs that have been completed in the region in the past 10 years.

Can a dredge of the lake occur before the EIS is complete?

No; dredging within the lake basin will not occur before:

  • An EIS is complete; and,
  • A long-term management option is selected for implementation.

This is consistent with precedent set in previous Capitol Lake EISs completed in 1976 and 1997, and the cooperative agreement between agencies and jurisdictions to identify a long-term management option before taking action.

Was a long-term management option selected in Phase 1?

No, an option for long-term management was not selected in Phase 1. Neither a long-term management plan nor actions such as initial dredging can be selected for implementation until a project-specific EIS is complete. The EIS would inform decision-makers on the potential benefits and impacts of the project. The EIS would occur in Phase 2.

During Phase 1, DES did solicit input from stakeholders and the community on new concept ideas for long-term management options. That information will be carried into Phase 2, for screening and preliminary evaluation in the initial stage of the EIS process. A range of reasonable long-term management options will be selected to carry forward for further evaluation in the EIS.

Were any long-term management options eliminated in Phase 1?

Just as DES did not select a long-term management option in Phase 1, DES did not eliminate options from consideration. Both of those steps will occur in Phase 2.

Would the Environmental Impact Statement (EIS) identify a preferred alternative for long-term management? How is that decision made?

A preferred alternative for long-term management is expected to be identified in the Final EIS. State law through SEPA does not prescribe the timeframe for identifying a preferred alternative.

The technical evaluation and alternatives analysis in the EIS will provide a basis of information that will be reviewed by DES and other decision-makers (including the State Capitol Committee and Washington State Legislature).

Using the EIS analysis, and carefully considering input from stakeholders (including the Executive Work Group and Technical Committee) and the community, DES is authorized to select the alternative that best meets the project goals, is feasible with regard to cost and sustainability, avoids or mitigates environmental impacts, and provides an environmental benefit.

What will happen if an Environmental Impact Statement (EIS) is not completed?

Without an EIS leading to a long-term management decision, conditions within the lake and watershed will continue to deteriorate:

  • More than 35,000 cubic yards of sediment will continue to accumulate in the lake basin annually.
  • Shallower conditions may negatively impact fish and other aquatic species.
  • Invasive plant species, such as Eurasian milfoil, could spread further within the lake basin, crowding out fish and wildlife habitat.
  • The invasive New Zealand Mudsnail, which spreads easily and reproduces quickly to high densities, will continue to pose a risk to other water bodies if the lake were to reopen to active public use.
  • High levels of phosphorous will continue to cause algae blooms, which leads to conditions that deplete oxygen levels in Budd Inlet.
  • Active use of the waterbody by the community is likely to continue to be prohibited.

Background and Current Conditions in Capitol Lake/Lower Deschutes Watershed

Is there a problem with Capitol Lake?

Capitol Lake is a popular destination in Olympia because of its beauty and accessible trails. Large numbers of birds, salmon and bats use the lake, offering a unique opportunity for watching wildlife in an urban setting. The hillsides surrounding the area offer magnificent views of the lake, Puget Sound, the Olympic Mountains and Mount Rainier.

But Capitol Lake has some problems.

Every year more than 35,000 cubic yards of sediment comes down the Deschutes River and settles into the lake. That's enough soil to cover a city block to a depth of three feet. Today, the lake is about 21 percent smaller and it holds roughly 60 percent less water than it did in 1951. Capitol Lake is turning into a marsh.

A shallow lake heats quickly in the summer. High water temperatures can stress fish and other aquatic species. Warm water also encourages the growth of aquatic weeds.

Capitol Lake does not meet water quality standards because of high levels of phosphorus, which causes algae blooms. When algae and weeds die in late summer, some of it washes out into Budd Inlet where it decomposes, using up oxygen essential for fish and other aquatic life.

The lake also has high levels of fecal coliform bacteria, which can pose a health risk if ingested. The bacterium is washed into the lake through the stormwater system.

Non-native weeds, such as Eurasian milfoil, are found in the lake and along the shoreline. These weeds crowd out native vegetation, reducing fish and wildlife habitat. Invasive species, like the New Zealand Mudsnail, are also found in Capitol Lake and can dominate lakebed habitat by outcompeting native aquatic snails and insects that other species depend on for food.

Before Capitol Lake was created, this area was an estuary, where freshwater from the Deschutes River mixed with the saltwater of Budd Inlet, part of Puget Sound. At the time the lake was created, the existing estuary had water quality problems and had been greatly modified by urbanization.

What is an estuary?

It is an area where freshwater from a river mixes with the saltwater of the ocean. An estuary is influenced by tides but protected from large waves. Generally, estuaries are among the most productive habitats on earth, according to the Environmental Protection Agency. Estuaries also provide flood control and filter out pollutants. More information about estuaries can be found on the Environmental Protection Agency's website.

Can an estuary be restored by keeping the Capitol Lake Dam open?

No. Deschutes Parkway and other infrastructure around the lake were not built to withstand tidal action. It isn't possible to move the large volume of water that is part of a high tide through the narrow opening – 85 feet – at the dam. The original Deschutes estuary opening, before the development of the city, was estimated to be about 2,000 feet wide. Estuary restoration will require construction of a new 5th Avenue Bridge with a 500 foot opening.

Which habitat would be better for fish and wildlife?

An estuary would provide habitat for species that depend on saltwater or brackish water, while a lake provides habitat for freshwater species. Some species use both habitats, preferring the one that provides the most food and protection from predators.

For example, an estuary may benefit salmon, crabs and some types of ducks, but there would probably be fewer bats, swallows and other types of ducks.

Is Capitol Lake polluted?

The lake has water quality problems, including high levels of phosphorus which can cause algae blooms, but it does not appear to be contaminated with industrial pollutants or toxic chemicals. The Thurston County Environmental Health Division monitors the lake for toxic algae blooms from May through October, and measures oxygen levels in the water. The lake's oxygen levels are normal throughout much of the year, but can be higher than normal during the summer, which can harm fish.

The lake is off limits to swimming because of fecal coliform bacteria. The water is murky because of the sediment and algae.

Would an estuary cause odor problems?

A restored Deschutes River estuary would probably smell like any other area adjacent to Puget Sound. The unpleasant odors reportedly coming from this area in the early part of the 20th century, as noted in some historical accounts, may have been due to the discharge of raw sewage. Wastewater is now treated before it goes into Puget Sound.

What about mosquitoes?

Most species of mosquitoes breed in freshwater, not saltwater. A restored Deschutes estuary would likely produce far fewer of these insects than Capitol Lake does. In fact, it is the large number of mosquitoes and other aquatic insects that hatch in the lake that draws thousands of bats, swallows and swifts to feed on them.

Who was on the committee looking at this issue?

The future of Capitol Lake was studied by the Capitol Lake Adaptive Management Plan (CLAMP) Steering Committee. The committee consisted of representatives from the Squaxin Island Tribe; the cities of Olympia and Tumwater; Thurston County; the Port of Olympia; and the departments of Fish and Wildlife, Natural Resources, Ecology and General Administration. The Legislature included a proviso in the 2010 Supplemental Capital Budget that mandated the suspension of the Capitol Lake adaptive management planning process, which then resulted in the CLAMP Steering Committee being brought to a close in May 2010.

The committee considered four alternatives for the future of Capitol Lake:

  • Status quo – Do not dredge the lake and continue current dam operations, weed control and other maintenance procedures.
  • Managed lake – Conduct a large initial dredge to restore the depth of the lake and then periodically dredge the new sediment coming down the river.
  • Estuary – Restore tidal action by dredging sediment; removing the dam and constructing a new 5th Avenue Bridge.
  • Dual basin estuary – Same as the Estuary alternative but with a barrier dividing the north part of the lake into a saltwater reflecting pool adjacent to Heritage Park, and an estuary adjacent to Deschutes Parkway.

In 2009, the members of the Advisory Committee recommended as follows:

  • Comprehensive Estuary Restoration: Thurston County, Squaxin Island Tribe, departments of Ecology, Fish & Wildlife and Natural Resources
  • Managed Lake: City of Tumwater, Port of Olympia
  • Undecided: City of Olympia

Common goals were also identified from the CLAMP process:

  • The need for development of an implementation plan which recognizes the placement of the lake within the larger watershed, the need for long-term solutions which are economically durable and community interests through coordinated and collaborative approaches;
  • Protection of fish passages for the Deschutes River;
  • Development of an equitable cost sharing structure between all relevant stakeholders and beneficiaries;
  • Development of a sediment management strategy for the lake basin; and
  • Identification of potential funding opportunities.

For more information

Linda Kent, DES Communications
(360) 407-7921,

Carrie Martin, DES Facilities Division
(360) 407-9323,