What lies beneath? Capitol Lake drained for estuary design study

Olympia’s Capitol Lake had a slightly different look and smell this week as engineers and project managers partially drained it to examine underwater infrastructure and sediment.

The work is part of a multi-million-dollar estuary restoration project that is expected to transform Olympia. The reflecting pond beneath the capitol dome will be removed and replaced with wetlands that provide a healthy fish habitat and a natural tidal exchange.

The draining started on Monday and reached its lowest levels mid-week. Design engineers needed to inspect pipes and outfalls – including the dam that created this reflecting pond for the capitol dome in 1951.

People walking around it could see a ring of exposed lakebed that’s several feet wide – and smell some of the underwater vegetation drying out along the shore. But the project managers said this is not a preview of what the estuary will look or smell like, once it’s restored.

Scott Stainer, one of the civil engineers designing the project, said draining the lake exposes problems that the transformation will fix.

“You know, 22 invasive species that are in it – it has extensive growth,” Stainer said. “And so what you're actually seeing is the growth that should not exist here.”

The invasive species include mud snails that have closed the lake to public use; the growth has contributed to critically low oxygen levels in Budd Inlet, which the Lake flows into.

Budd Inlet is part of Puget Sound, where water quality mandates compelled the state to opt for dam removal over proposals to renovate and better manage the lake.

Returning the estuary to a more natural state will provide vastly improved habitat for endangered Chinook and Coho salmon that are known to frequent the area; it’s hoped that it will encourage the return of other depleted species and shellfish. It will also help address Olympia’s chronic flooding that will only get worse with climate change.

The hope is to start construction in 2027, with dam removal expected around 2030. But currently, design work on the Capitol Lake estuary restoration is only about 15% done.

The state is inviting the public to submit feedback at a public meeting on August 19th and targeting stakeholders for input.

Ann Larson is the Project Director for the state and has already presided over extensive outreach. She said it’s true that some people still wish they could keep the lake, which provides a popular walking path through several natural areas that host wildlife in the heart of downtown Olympia. But once people start to understand all the benefits of the estuary that will replace it, she expects they’ll come around.

“We're looking at boardwalks where people can really get out on the water,” she said. “Wildlife benefits, fish benefits, and then really start to see holistically the whole picture.”

She said it’s a legacy project that is bringing the state, city and port together with the Squaxin Island Tribe to transform the heart of Olympia.

Produced with assistance from the Public Media Journalists Association Editor Corps funded by the Corporation for Public Broadcasting, a private corporation funded by the American people.