Budd Inlet Dissolved Oxygen TMDL

Budd Inlet is the southernmost section of Puget Sound. Portions of it do not meet water quality standards for dissolved oxygen. We are working with partners in the Deschutes River basin to address these impairments and restore these waters to state water quality standards.

Water quality issues

The Deschutes River flows into Capitol Lake, which empties into Budd Inlet. Thurston and Lewis counties, the cities of Olympia, Lacey, and Tumwater, and the town of Rainier are in this basin. Major land uses include urban residential, commercial, recreational, and some industrial. The marine waters of Budd Inlet currently do not meet water quality standards for dissolved oxygen.

Our final plan

We submitted the Budd Inlet Dissolved Oxygen Total Maximum Daily Load (TMDL) water quality improvement plan to EPA for approval on Oct. 26, 2022. EPA approved the TMDL on Dec. 16, 2022. This water quality improvement plan aims to address low dissolved oxygen levels within Budd Inlet. The goal of this plan is to identify water quality and watershed improvements needed to protect salmon and other aquatic life within Budd Inlet.

We held a comment period from June 8, 2022, through July 25, 2022. Public comments and our response to comments are included in an appendix to the plan.

Once implemented, this plan should lead to an increase in dissolved oxygen levels within Budd Inlet. Higher dissolved oxygen will help the Budd Inlet ecosystem and enhance local fishing, shellfishing, and other uses of the Inlet.

What we have done

We began water quality monitoring, computer modeling, and analysis for this water quality improvement project in 2003. We published the technical report study findings for the entire watershed in 2012. Two peer reviews of the model were completed in 2014. Additional computer modeling work resulted in a supplemental modeling scenarios report in 2015. We are now working on the marine waters of Budd Inlet and Capitol Lake.

We started developing the Budd Inlet Dissolved Oxygen TMDL (or water cleanup plan) in 2016. Through many meetings with local jurisdictions, Tribes, permittees, and stakeholders, we drafted a cleanup plan designed to address dissolved oxygen impairments within Budd Inlet while meeting the needs of local communities. This plan was open to public comment from June 8 to July 25, 2022. We hosted online public workshops on June 21 and 22, 2022.

The most important cleanup action identified within our plan is implementing a long-term management solution to Capitol Lake. Modeling shows that Capitol Lake is the largest contributor to low dissolved oxygen within Budd Inlet and that restoring Capitol Lake to an estuary would allow Budd Inlet to meet water quality standards. The Department of Enterprise Services published a decision on Oct. 31, 2022, that identified this solution as their "preferred alternative" to the present method of lake management. This decision is consistent with the recommendations of the Budd Inlet TMDL. 

Why this matters

Water must be of high quality to support fish and wildlife, and dissolved oxygen is an important component of water quality.

Dissolved oxygen — Like people, fish and other aquatic organisms need oxygen to live. An abundance of nutrients in a waterbody can cause algae to grow at excessive rates. When algae decomposes, it uses up oxygen, creating low dissolved oxygen conditions and robbing fish and aquatic life of the oxygen they need to breathe.

Therefore, it's critical to maintain an adequate amount of oxygen in the water. Without enough dissolved oxygen, local ecosystems, fishing, shellfishing, and other aquatic life will be negatively affected.