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Climate change resilience and your drinking water

For over 100 years, Portland water customers have enjoyed high-quality drinking water at their taps. We are prepared to adapt and plan for a warming climate to continue to provide water that's safe and abundant for years to come.

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Climate impacts and system resilience

We are dedicated to understanding and preparing for a range of climate impacts to the City of Portland's drinking water system. Climate change response is an objective identified in our five-year Strategic Plan and it guides the integration of climate preparedness work into our daily operations. While Portland's water system has some fundamental climate resilience already built in, emerging risks and disruptions from climate change will present new challenges.

Climate models project a warmer Northwest with hotter, drier summers, and warmer, wetter winters with heavier rainfall and less snowfall. As the long-term climate shifts, we anticipate a range of extreme conditions will impact the region in the future, even as individual weather years continue to be seasonally variable.

A rain-fed water supply

Portland's water supply reservoirs in the Bull Run Watershed depend mostly on seasonal rainfall, with smaller amounts of snowfall contributing to the overall water supply. The temperate rainforest of the Bull Run Watershed gets as much as four times the precipitation of Portland.

A dark blue Bull Run Lake surrounded by green forested hills and a snow-capped Mount Hood in the background
Portland's drinking water reservoirs in the Bull Run Watershed refill annually from seasonal rainfall.

Despite the reliable rainfall, the watershed is experiencing the impacts of a warmer climate. An analysis of environmental data and hydrologic trends in the watershed shows significant trends of increasing air temperatures, decreasing summer streamflows, and increasing water temperature in streams throughout the Bull Run. Climate modeling conducted by our researchers indicates that rising air temperatures in the coming decades will lead to lower snow volumes, earlier snowmelt, higher winter peak streamflows, and lower summer streamflows in the Bull Run Watershed.

Water system climate resilience

We have been working to understand and prepare for the impacts of climate change to the water system for over two decades, and we are planning adaptively for the future. Each year, we develop a Seasonal Water Supply Augmentation and Contingency Plan, which helps guide the management of the drinking water system and prepares us to meet a range of supply and demand conditions.

aerial shot of a groundwater pump station next to the Columbia River
Portland's groundwater supply increases the water system's resilience to climate change.

Portland's groundwater supply, the Columbia South Shore Well Field, is a high-quality, reliable water source. It is a critical factor in the long-term climate resilience of the water system. The groundwater system is frequently used to supplement summer demand and if necessary, it can be used to provide an emergency water supply.

Portland has experienced decreasing water demand in the last two decades despite increasing population. This can be attributed to changes in land use, customers being more water-wise, and water-efficient appliances. Due to declining water demands, the availability of two high-quality supply sources, and adaptive planning, our water system is expected to meet customer water needs into the future.

Research and partnerships

The Water Bureau actively works with research institutions and climate scientists to assess how climate change could affect the drinking water system, and to develop tools to inform future water supply planning. We are currently in a leadership role in the Water Utility Climate Alliance (WUCA), a group of twelve water utilities that collectively serve drinking water to 50 million Americans. WUCA's mission is to collaboratively enhance climate research and improve water-management decision making to ensure water utilities can respond to climate change and protect their water supplies. We have codeveloped and coproduced several reports and tools on climate assessment and adaptation solutions with WUCA. These include preparing for how climate risks will affect built assets and infrastructure, how engineers can better prepare for climate change, and how extreme weather events could affect the health and safety of outdoor workers who keep the water system operating 24/7.

Learn more about water utility climate adaptation from WUCA.

The Water Utility Climate Alliance (WUCA) is a collaboration of water utilities around the country dedicated to enhancing climate research and improving water-management decision making.

City of Portland climate work

In addition to partnering with national climate leaders and scientists, we collaborate with City of Portland bureaus and other local public agencies to reduce carbon emissions and develop climate-resilient strategies for the region. Many citywide strategies and actions are identified in the City of Portland Climate Action Plan.

We are committed to reducing our carbon footprint to meet the carbon emissions and equity goals of the City of Portland Climate Emergency Declaration. Tracking and reporting operational carbon emissions, energy use, and renewable energy generation allows us to set more aggressive organizational goals to respond to the climate emergency.