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Highway 99 retrofits along Echo Lake study

In this project, King County is evaluating the effectiveness of a large improvement project to add stormwater treatment along a lake waterfront.

This project adds stormwater treatment to a three-mile section of SR 99 along Echo Lake in Shoreline, Washington. The area has undergone a series of retrofits for stormwater treatment including bioretention, filter boxes, and detention.

Study questions

The study’s sampling quality assurance project plan provides information on the study design.

  • How effective is each individual best management practices (BMP) at treating stormwater under this large retrofit project?
  • What well does the entire retrofit protect Echo Lake from pollutants?
  • What is the potential protection to the lake itself?

Scope of work

Study findings

The sampling phase was completed in early 2017 and King County published the Monitoring Stormwater Retrofits in the Echo Lake Drainage Basin - SAM Effectiveness Study Final Report and appendices in late 2017.

Project tasks and deliverables

Task 1 Planning progress reports, draft and final QAPP D1.1 D1.2 D1.3 D1.4      
Task 2 Field sampling and analysis, quarterly progress reports D2.1 D2.2 D2.3 D2.4      
Task 3 Echo Lake historical data summary report, draft and final D3.1 D3.2          
Task 4 Data analysis progress reports, draft and final project report D4.1 D4.2 D4.3FinalReport D4.3appendices
Task 5 Distribution of findings: EIM, BMP database, presentations D5.1 D5.2 D5.3Symposium D5.4 D5.5 D5.6
Task 6 Project Management: semi-annual progress reports D6.1 D6.2 D6.3 D6.4 D6.5 D6.6 D6.7