Paired watershed retrofit & restoration study
The City of Redmond is the lead agency on this multi-year complete watershed-scale stormwater retrofit effectiveness study.
There are seven watersheds in this study design:
- Three application watersheds: Evans, Monticello, and Tosh
- Two reference watersheds: Colin and Seidel
- Two control watersheds: Country and Tyler's
Application watersheds will undergo large-scale retrofits to bring the watershed into current Washington stormwater management standards. Control watersheds will progress at a normal timeline of development. Reference watersheds will not develop as they are in relatively protected environments.
All watersheds included in the study are located in and around Redmond. This project will monitor the streams draining these watersheds for various hydrologic, chemical physical habitat, and biological indicators.
Study questions
- How effective are watershed-scale rehabilitation efforts at improving conditions for small stream receiving waters?
Scope of work
This effectiveness study will span 10 years (2015-2025), currently monitoring is funded through March 2023. Due to the extended timeline on this project, only the most important tasks and deliverables are summarized. The study’s sampling quality assurance project plan provides information on the sites and study design. The sub-project effectiveness studies for Pond Retrofit and Street Sweeping are described under addendums or separate monitoring plans than the original QAPP.
Planning and preparation deliverables:
- Literature review for monitoring approaches and key indicators
- Experimental design
- Quality Assurance Project Plan, Addendum 1 Street Sweeping
- Purchase and installation of monitoring equipment (photos)
- King County Hydrologic Information Center website for flow and in-situ water quality (search on RPWS)
- 2021 RPWS Pond Retrofit Effectiveness Monitoring Plan
Study findings
- SAM Fact Sheet #6 (April 2018): Redmond Paired Watershed Study - Status Update
- SAM Fact Sheet #23 (April 2021): Redmond Paired Watershed Study - Interim Findings
Water Year Final Reports and Trend Reports:
- Water Year 2016 Data Report (data for Oct. 2015 to Sept. 2016)
- Water Year 2017 Data Report (data for Oct. 2016 to Sept. 2017)
- Water Year 2018 Data Report (data for Oct. 2017 to Sept. 2018)
- Water Year 2019 Data Report (data for Oct. 2018 to Sept. 2019)
- Trend Analysis Report Water Year 2016 through 2019, 2023 Memo: Hydrologic Indicator Reporting Errata
- Water Year 2020 Data Report (data for Oct. 2019 to Sept. 2020), 2023 Memo: Hydrologic Indicator Reporting Errata
- Effectiveness of Street Sweeping pilot study: data validation memo and final report and 2 page summary
- Water Year 2021 Data Report (data for Oct. 2020 to Sept. 2021)
- Water Year 2022 Data Report (data for Oct. 2021 to Sept. 2022)
- Trend Analysis Report Water Year 2016 through 2022
The report's appendices contain multiple incremental deliverables such as the hydrologic summary, King County’s data quality assurance review, water quality summary, and sediment quality summary.
Contact information
Brandi Lubliner
Stormwater Action Monitoring Coordinator
brandi.lubliner@ecy.wa.gov
360-628-4989