Intensively Monitored Watersheds (IMWs)


This webpage is intended to act as a place for information about Intensively Monitored Watersheds (IMWs) to be shared between IMW teams, as well as to disseminate lessons learned from IMWs with the public, restoration practitioners, resource managers, salmon recovery NGOs, and local, state, and federal officials and legislators. The website will be updated regularly as information comes available from IMWs which are long-term investments into learning how effective restoration is at recovering endangered salmon and steelhead.

We are pleased to announce the much anticipated IMW papers are now published in AFS' Fisheries February 2016 issue! They are available on line now (see links below) and soon to be in your mailbox, if you have a paper subscription to Fisheries.

In 2005, PNAMP recommended establishing a regional network of Intensively Monitored Watersheds (IMWs) to evaluate the effectiveness of restoration projects, programs and policies at the landscape scale. The basic premise is that the complex relationships controlling salmon response to habitat conditions can best be understood by concentrating and integrating rigorous monitoring and research efforts at a few locations. IMWs reduce the complications of monitoring project effectiveness, increase the comprehensiveness of monitoring, and increase efficiencies through shared responsibilities.

To date, PNAMP has produced the 2005 IMW strategy, followed up by a white paper describing the overall suite of action effectiveness approaches and a context for how IMWs fit in and has hosted 2 workshops (2008 and 2013). More than 80 participants attended the 2013 workshop and shared lessons learned from current IMWs and offered and recommendations for future work. PNAMP will host new materials as a result of this workshop, so stay tuned for easy access here (this web page) and new materials developed for technical and non-technical audiences.

For more information about PNAMP activities on this topic, click on "Events", "Documents" and "Key Documents" in the bottom right corner of this page.

IMW Papers Published!

April 23, 2016 - 9:41am

Intensively Monitored Watersheds provide powerful insight into effects of stream restoration

An emerging research method to gauge the benefits of stream restoration for salmon and other native fish is revealing improvements in fish numbers, survival and reproduction in key rivers across the Pacific Northwest, according to a new research paper describing the approach, known as intensively monitored watersheds, or IMWs. At least 17 intensively monitored watersheds in the Northwest are beginning to provide detailed scientific insight into how the millions of dollars invested in river and stream restoration can most effectively boost fish populations, according to the new paper published February, 2016, in Fisheries, the monthly journal of the American Fisheries Society.

Check out "Progress and Challenges of Testing the Effectiveness of Stream Restoration in the Pacific Northwest Using Intensively Monitored Watersheds" (Bennett, Pess, Bouwes et al. 2016), and its companion essay, "Adapting Adaptive Management for Testing the Effectiveness of Stream Restoration: An Intensively Monitored Watershed Example" (Bouwes, Bennett and Wheaton 2016).

Thanks to everyone who contributed to these papers, who implements IMWs on the ground, and who participated in the 2013 PNAMP IMW workshop, which was the inspiration for this work.

You can learn more about PNW IMWs at this new PNAMP web resource:

PNAMP is planning another IMW workshop for fall of 2016 - stay tuned!

Follow up to IMW Workshop (September 26, 2013)

September 26, 2013 - 2:20pm

Follow up to IMW Workshop (March 20-21, 2013)
This workshop convened more than 80 practitioners currently working in the field of Intensively Monitored Watersheds (IMWs). Presentations included details of current IMWs with an emphasis on lessons learned and recommendations for current and future IMW projects. Fifteen IMW studies were presented - from across the Northwest including the Columbia River Basin, Puget Sound, and the Oregon, Washington, and northern California coasts. In-depth discussion sessions moderated by leading IMW scientists and other experts in communication and data management followed the presentations on Day 2 of the workshop. Discussion sessions focused on key aspects of designing and implementing IMWs, including experimental design, data analysis, data management, coordination of restoration activities with monitoring efforts, and communication.
IMW practitioners shared their successes, failures, and insights on the challenges of this coordinated experimental approach that integrates watershed-level restoration activities with carefully designed and intensive monitoring efforts. This workshop was an opportunity for IMW practitioners to document and integrate their experiences to strengthen current and future IMW efforts and to identify the next steps PNAMP could take to assist practitioners in the planning and implementing IMWs.

Presentations are posted on the PNAMP website here:

Workshop notes are posted on the PNAMP webpage here:

Products from the Workshop
The workshop resulted in a summary of all current IMW projects. The summary contains information from sixteen different IMW projects, including lessons learned, recommendations, purpose and scope of the project, design information, analysis details, sponsor and cooperators, etc.

IMW summary document is posted on the PNAMP web page here:

PNAMP will post additional products as they are completed.

Thanks to all who planned, presented, moderated, and participated!

Billions of dollars have been invested in stream restoration across the United States since 1990, but opportunities to learn from and improve restoration actions have been severely limited due to a lack of recording of basic project details and limited monitoring (Bernhardt et al. 2005). The Pacific Northwest has some of the largest investments in stream restoration in North America, primarily driven by the listing of anadromous salmon (Oncorhynchus spp.) and steelhead (O. mykiss) populations under the Endangered Species Act (ESA; Katz et al. 2007; Roni et al. 2002). An underlying assumption of much of the stream restoration in the Pacific Northwest is that improvements in freshwater habitat will lead to increased population viability, and ultimately delisting as a threatened or endangered species (NMFS 2014). However, there is a lack of evidence that past stream restoration projects have benefitted salmon and steelhead populations (Roni et al. 2008). Population responses to restoration have rarely been documented because many restoration projects have not conducted effectiveness monitoring at the population scale. Instead, monitoring has tended to focus on the reach scale and has occurred over short time periods (i.e.,

We define an IMW as an experiment in one or more catchments with a well-developed, long-term monitoring program to determine watershed-scale fish and habitat responses to restoration actions (e.g., Zimmerman et al. 2012).

Most IMWs are still in either the pre-treatment phase or the early stages of post-treatment; however, the experimental design, restoration, and monitoring plans are in place to answer questions concerning the effectiveness of restoration actions.

Preliminary results from some IMWs provide insight into fish and habitat responses at multiple spatial and temporal scales pre- and post-restoration. However, there have also been numerous reported difficulties including a lack of coordination between restoration, monitoring, funding, and implementing entities and lack of consistent funding.

The populations being studied have variable life histories that require monitoring for 2–5 or more years to assess a single cohort. This means experiments will likely need to be at least 10 years long, if not longer, requiring significant investments in monitoring infrastructure and maintenance.

Though IMW experiments take time, they are the fastest, most reliable approach to measure population level responses and to assess the efficacy of habitat restoration efforts.

Individual IMWs


Bridge Creek


Document Title
Summary Elwha Draft


Hood Canal


Lower Columbia


Middle Fork of the John Day




Strait of Juan De Fuca

Ten Mile (CA)

Tenmile (OR)