Puget Sound Nutrient Reduction Project

The Puget Sound Nutrient Source Reduction Project is a collaborative effort with Puget Sound communities and stakeholders to address human sources of nutrients. This work focuses on using the latest science to find the right solutions for regional investments to reduce nutrient sources. Our objective is to improve Puget Sound water quality to support salmon and orca recovery and increase resiliency to climate impacts.

In 2018, the Puget Sound Nutrient Forum was formed as a large public advisory group for the project to discuss, learn, and provide input on how to reduce human sources of nutrients entering Puget Sound. The forum meets regularly. Please visit the Puget Sound Nutrient Forum meeting page to see the upcoming meeting schedule and see resources related to the project. You can also register to receive email updates on the project.

Decision to move forward with Nutrients General Permit

On January 30, 2020, we announced our decision to move forward with developing a draft Nutrients General Permit in Puget Sound. The proposed Nutrients General Permit would apply to nearly 70 WWTPs discharging to marine and estuarine waters of Puget Sound. Visit the Nutrients General Permit webpage for more information. 

Evaluating nutrient management using state-of-the-science tools

We use the Salish Sea Model and water quality monitoring data to analyze and quantify nutrient impacts from sources both nearby and farther away from observed problems. The model helps us to understand the impacts of human nutrient sources and how potential source reductions could improve Puget Sound water quality. Decades of water quality monitoring data helps us understand how Puget Sound water quality is changing over time. 

The latest Salish Sea Model results confirm that discharges of nutrients from human sources are leading to dissolved oxygen problems in many parts of Puget Sound. In 2019-2021, we will evaluate different combinations of human source nutrient reduction levels and their potential water quality improvement in Puget Sound. This will inform future actions so that we invest in strategic solutions for improving marine water quality.

Preparing for population growth and climate change

There are currently over 4.5 million people living in the Puget Sound region. The Puget Sound Regional Council estimates around 1.8 million more people will move to the region by 2050. This population increase could mean more than a 40 percent increase of nutrients to Puget Sound from human sources over the next few decades.

Climate change will also make conditions worse. Drought years will lessen freshwater streamflow into Puget Sound, which reduces circulation. This results in large nutrient concentrations from human sources staying in the Sound because the nutrients are not flushed out into the ocean. Additionally, increasing water temperatures will increase bacteria and jellyfish and flagellates. It also lowers dissolved oxygen in the water that fish and marine organisms need to survive.