Redmond Paired Watershed Study Project, City of Redmond

The Redmond Paired Watershed Study (RPWS) is one of four effectiveness monitoring studies that was selected for implementation starting in 2014 for the Regional Stormwater Action Monitoring (SAM) program for Puget Sound. The goal of effectiveness monitoring under the SAM program is to provide widely applicable information for improving stormwater management in the region.

The specific study question to be addressed through the RPWS is as follows:

How effective are watershed rehabilitation efforts at improving receiving water conditions at the watershed scale?

To address this study question, the RPWS will involve the collection of routine and continuous measurements of various hydrologic, chemical, physical habitat, and biological indicators of stream health over an extended time in seven watersheds categorized as follows:

• Three “Application” watersheds with wadeable lowland streams that are moderately impacted by urbanization and prioritized for rehabilitation efforts.

• Two “Reference” watersheds with relatively pristine wadeable lowland streams that do not require rehabilitation.

• Two “Control” watersheds with significantly impacted wadeable lowland streams by urbanization that are not currently targeted for rehabilitation pursuant to the WMP.

The pattern of interest will be evidence that receiving water conditions are improving in the Application watersheds while conditions in the Reference and Control watersheds remain relatively static. In addition to this monitoring, the effectiveness of specific structural stormwater controls in the watersheds that have been targeted for rehabilitation efforts will also be confirmed based on measurements of hydrologic and chemical parameters that are collected over a shorter timeframe. A more detailed description of the experimental design procedures that are being used for this monitoring can be found in the Quality Assurance Project Plan for the RPWS (Herrera 2015).