Clackamas Watershed Research

Over 300,000 people in Clackamas and Washington Counties depend on the Clackamas River Basin (CRB) for high quality drinking water and other watershed services such as stormwater and sanitary sewer management. The watershed is also an important source agricultural and forestry products, and provides aquatic, terrestrial, and snow-based recreational opportunities to people from across the Portland metropolitan area and beyond. As a multi-purpose watershed, a key challenge is how to bring together stakeholders with a diverse array of objectives to ensure the resilience of watershed in the face of a changing climate, growing demands for services from the watershed, requirements for fish and wildlife, and the livelihood needs of those who depend on the watershed. This webpage presents a case study of research focused on understanding the social and ecological dynamics of the Clackamas Watershed.

The Clackamas River watershed clockwise from top left: Mt Hood above forests, ESA protected salmon, aquatic recreation, technical assistance to landowners, and riparian and floodplain corridors.

Clackamas River Watershed Resilience Project Overview

The Clackamas River Watershed Resilience project was a multi-year project aimed to provide water resource stakeholders in the Clackamas River Watershed (CW) with guidance for managing resilience in the face of climate change. Phase I of this project was primarily funded by PSU Institute for Sustainable Solution to establish a baseline of historical trends in the Clackamas River watershed relevant to climate change and identify issues pertinent to stakeholders in the context of climate change (e.g., diminished summer water supply, water quality degradation resulting from urban development and intense rainfall, etc.). Phase II of this project sought to continue that research with two objectives: (1) Applied Climate Science, (2) Climate Adaptation Planning.


The goal of the Clackamas Watershed Resilience project is to help project partners understand local impacts of climate change on water quality and quantity in the region; and develop strategies to sustain a healthy, reliable water source.

Uncertainty related to local impacts of climate change present a challenge for regions who are making infrastructure investments and policy decisions today that will remain in place for decades. This project aimed to provide locally specific information, at a finer scale than what is available through global climate models about how climate change may threaten water quality and quantity in the Clackamas River basin.

Alongside climate scientists, faculty and students with social science and natural resource management expertise worked with the Clackamas river community and key stakeholders to develop recommended strategies for adapting to climate change. The executive summary is a summary of the second phase of work for on this project, which began in March 2017. A full report from the first phase of work is also available below.

The Northwest Climate Conference Special Session on

the Clackamas Resilience project

The Northwest Climate Conference provided an opportunity for the project team to provide an overview of the project and a facilitate a panel and audience discussion on conducting interdisciplinary applied climate impact assessment. An audience of close to 50 people attended. The session started with an overview of the project, followed by a series of 5 minute flash talks on the science findings, and concluded with a panel discussion with representatives from the Clackamas River Water Providers, Water Environment Services of Clackamas County, and the Institute for Sustainable Solutions at Portland State. The slides from the session are posted below.


Clackamas Watershed Resilience Workshop

May 13, 2019 - Clackamas County Development Services Building Auditorium

This multi-phase applied team workshop developed from a research partnership with local community partners, PSU faculty, and graduate students to inform local understanding of Clackamas watershed resilience to climate variability and change.

The Clackamas Watershed Resilience workshop was focused on communicating and engaging with research conducted in 2018-2019 by PSU faculty and graduate students. The research was conducted as Phase 2 of the Clackamas Watershed Resilience workshop, which aimed at developing and evaluating climate change impact models for the watershed, and simulating and assessing future conditions in Clackamas hydro-climate system. Ultimately, the project goal is to make statements about temperature, snowfall, wildfire, and water quality such as, “The frequency of extreme events is projected to increase/decrease/remain the same by the mid/late 21st century,” while also fostering dialogue among stakeholders and resource management about how to adapt to those changes.

Towards that end, 48 water and natural resource managers, elected officials, scientists, and other engaged stakeholders met for 3 hours to:

      • Learn about the latest climate impact science for the Clackamas River watershed, including a focus on temperature, precipitation and snowpack, water quality and quantity, wildfire, and stakeholder perspectives on adaptation.
      • Identify priorities to best build on the assets within the Clackamas River watershed to address the vulnerabilities and risks faced by the watershed.

The workshop was organized to maximize engagement between project scientists and stakeholders. First, participants engaged in a round robin poster session on the latest climate impact science specific to the watershed with posters on:

          1. Temperature & precipitation/snowpack
          2. Hydrology and water quality
          3. Wildfire
          4. Stakeholders

Second, groups of 10-12 engaged in breakout discussions addressing the following questions:

          1. How is this research important to you and/or your organization?
          2. What actions are already occurring to address these challenges?
          3. What opportunities exist in current initiatives or do you think would be important to pursue in the future?
          4. What are the priorities for addressing these future climate risks?

Results from the poster session and discussions included

  1. Participants noted the importance of translating scientific data to interpretable narratives for stakeholders and broader audiences to help communicate the potential impacts from climate change and relevant adaptation options.
  2. Existing activities and future opportunities focused around the themes of infrastructure considerations, environmental conservation efforts, planning and management initiatives, community and professional engagement, and investment in science and research.
  3. Discussion about priorities for the future focused on (1) maintaining ecosystem health for the CRW (including the river, tributaries and forested areas), (2) focusing on education and outreach efforts, (3) increasing organizational collaboration and program efficiency, and (4) establishing management and research priorities.
  4. Adaptation strategies will likely fall into one of four categories:
    • Alternative, bigger, or new green and grey infrastructure for drinking, storm, and wastewater management,
    • Alternative sources of drinking water,
    • Alternative land management strategies that impact watershed health and function, and
    • Water conservation strategies implemented by water consumers.
  5. Next steps should focus on continued convening around climate adaptation planning, including incorporating climate impact research into current and near future projects and initiatives in the watershed, such as the Clackamas County Climate Action Plan and the Clackamas County Watershed Health Plan, local cities’ climate action plans, and US Forest Service climate vulnerability assessments.

Clackamas Watershed Resilience: Understanding the influence of climate variability and change on water resources

Clackamas Watershed Resilience - Phase I Report 2018.pdf

This multi-phase applied team research project developed in partnership with local community partners, PSU faculty, and graduate students to inform local understanding of Clackamas watershed resilience to climate variability and change. Phase 1 of the project occurred in 2017-2018 and was focused on establishing a baseline understanding of historically observed data about hydro-climatological relationships in the watershed. The report to the left focuses on stakeholder interests in resilience, as well as historical changes in climate, hydrology, fire, and resource management in the Clackamas watershed. The objectives of the project were to:

    1. Help clarify the extent to which the quantity, quality, and timing of water resources provided by the Clackamas have changed in recent history and
    2. Build a framework for understanding how susceptible Clackamas water resources are to impacts from climate change into the mid and late 21st century.

Our findings focus on the following:

    1. Stakeholders are interested in more engagement around climate resilience and adaptation. Locally relevant scientific information is needed to help facilitate further stakeholder engagement on resilience.
    2. The timing and amount of snow impacts water quantity, and extreme precipitation events have an impact on water quality.
    3. Urbanization in the Clackamas impacts water quality by reducing the response time between precipitation and increased turbidity.
    4. Wildfire in the Clackamas is driven by extreme drought conditions observed up to one month before fires tend to start, but a humid august can be an important control limiting wildfire growth.

Watershed Management and Private Lands: Moving Beyond Financial Incentives to Encourage Land Stewardship

The 2015 Clackamas River Watershed Survey - Landowner perspectives on watershed stewardship programs.pdf

by Matt DeAngelo

There is increasing recognition amongst water resource managers of the role that private landowners play in determining downstream water quality, but bringing together landowners with a wide variety of land management objectives under the umbrella of watershed stewardship remains a challenge. Recently, “Payment for Watershed Services” programs have aimed to engage private landowners in watershed stewardship initiatives by offering financial incentives for adopting watershed best management practices. However, whether financial incentives are sufficient to encourage widespread watershed stewardship is unknown?

My masters research explores the variety of attitudes and motivations driving landowner decisions to enroll in watershed stewardship programs. This project was designed to provide water resource managers practical recommendations to better engage private landowners in watershed stewardship. The research primarily addresses three questions:

  1. What are the barriers to enrollment in watershed stewardship programs?
  2. What types of landowners are in the watershed, and how do they differ?
  3. What policy tools are most likely to be effective with this populace?

In order to address these questions, we completed a mail and web-based survey in the Summer of 2015, distributed to nearly 1,000 private agricultural, forestry, and residential landowners in the Clackamas River watershed. We received 279 valid responses for a 29% response rate. Most survey respondents reported support for water quality outcomes, but there remained widespread distrust of governmental agencies and regulatory implications of program enrollment. Our findings suggest that landowners are largely motivated to manage their land under self-initiative and are concerned for losing the freedom and independence associated with owning land - emphasizing the importance of engaging landowners through a flexible, bottom-up approach.

A report of the data is available in the “Clackamas Landowner Summary Report.” More in-depth analysis is available in my thesis and the following paper in the journal Society & Natural Resources.

Deangelo, M. and M. Nielsen-Pincus. 2017. Choosing the right policy tools to encourage watershed stewardship through the study of attitude. Society and Natural Resources 30(11):1328-1342.



The 2016 Clackamas River drinking water customer survey - Customer perspectives on source water protection.pdf