Water Quality

The Issue: Stormwater can quickly run off impervious surfaces delivering potentially polluted water to streams and rivers in the Puget Sound region. Runoff from impervious surfaces can either be directly connected to streams through stormwater pipes or indirectly connected if runoff is routed to some other surface such as grass or a feature like a stormwater management structure. It is currently...

The Issue: Forests in the Pacific Northwest have changed substantially over the past hundred years because of logging, changing forest management methods, and climate change. These forests contain a dense network of small headwater streams that supply cold, clean water and support 52 amphibian species. These amphibians live both in the cold streams and in the cool, moist areas nearby. Natural...

The Issue: Changes in the water temperature and flow regimes of rivers throughout the western United States have contributed to shifts in the ranges of aquatic species that they support. Cold-water species such as fish are sensitive to changes in water temperature, which regulates their physiological functions and behavior. How USGS will help: A spatial stream network (SSN) model was developed...

Pacific salmon and trout, especially coho, are threatened by a toxic contaminant resulting from tire additives that end up in untreated road runoff. This contaminant, 6PPD-q, has been associated with high rates of coho pre-spawn mortality in streams, including in the Green-Duwamish watershed. Many coho spawning streams in the watershed are predicted to be at high risk for “urban runoff mortality...

The Issue: Scientists and water-resource managers recognize the increasing impact of wildfires on water supply in the western U.S. The increasing frequency and severity of wildfires are linked to changes in snowpack, warmer temperatures, and drought. Sedimentation following wildfire can impact aquatic habitat, reservoir storage capacity, water quality, and thus public drinking water supplies...

The issue: Stormwater runoff often carries pollutants that degrade water quality in receiving waters. A regional-scale monitoring program is necessary to objectively measure and track progress in reducing stormwater impacts on environmental health. How USGS will help: Scientists from the U.S. Geological Survey (USGS) are monitoring water quality and watershed health for urban and urbanizing areas...

The Issue: Polycyclic aromatic hydrocarbons (PAHs) are a class of oil-derived compounds widely distributed in fresh and marine waters. They pose a significant toxicity risk to fish. It can be challenging to pinpoint the source of PAHs found in wild fish populations. PAHs are widespread and come from many sources, so it is hard to determine whether fish exposure is event-related or consistent with...

The Issue: Mercury contamination and toxicity threaten Pacific lamprey recovery in the Columbia River basin. Methylmercury concentrations in larval Pacific lamprey from tributaries in the mid-Columbia were measured to be as high as 4.0 µg/g wet weight. At these concentration levels, injury is predicted to occur in more than 50% of larval and adult fish and more than 90% of early-life stage fish...

The Issue: The Chehalis River deposits sediment in Grays Harbor, which the U.S. Army Corps of Engineers regularly dredges to maintain shipping access. The sources and overall volumes of sediment transport in the lower river were last assessed in the 1960s. Given substantial changes in land-use and watershed regulations over the subsequent half-century, there is an open question as to if or how...

The Issue: Native American treaty rights depend on the availability of adequate and high-quality streamflow across the Western Washington, which can be degraded by water and land use, reservoir operations, and climate change among other factors. Streamflow during critical low-flow periods depend on groundwater discharge from aquifers, which also is vulnerable to human activities in the Western...

Wildfires can negatively impact reservoirs and water supply. In 2021, a wildfire in Okanagan County, Washington, engulfed a large area around Conconully Reservoir. USGS scientists are assessing sediment and water quality in the reservoir and surrounding streams.

The Issue: Past activities at Joint Base Lewis–McChord (JBLM)—located in west-central Washington—resulted in releases of hazardous waste and contaminants to the environment, and the most recent chemical of concern is per- and polyfluoroalkyl substances (PFAS). PFAS can enter groundwater and travel through the subsurface. Water-resource managers need to understand where groundwater flows in order...