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.