Images

A gravelometer is a field tool used to measure and classify the size of sediment particles, like gravel, cobbles, and boulders, in streams and rivers. It’s a rectangular metal plate with different sized holes corresponding to standard grain-size classes.

USGS hydrologic technician, Cara, collects an eDNA sample in triplicate using an eDNA Sampler.

USGS hydrologic technician uses a ruler called a gravelometer to classify streambed particles into size classes. These data can be used to calibrate models of streambed sediment. 

Freshwater mussels can be hard to find because they nestle into riverbeds. With new tools, we can find mussels by looking for their DNA in water samples in the lab.

Fragilaria crotonensis is a well-known species of planktonic diatom within the genus Fragilaria, commonly found in freshwater lakes across North America and other temperate regions.

Two technicians deployed the water-quality monitor for the 2025 season on the dock at OMSI. See the data live: Willamette River Below the Holgate Channel, Portland, OR

USGS staff member collects sediment samples at the upstream Chicken Creek water-quality monitoring location in the Tualatin River National Wildlife Refuge.

USGS hydrologist, Erin Leahy, collecting data in Chicken Creek in the Tualatin River National Wildlife Refuge. The USGS operates two water-quality monitors along Chicken Creek.

USGS hydrologic technician, Heather Bragg, uses a 2-wheel crane to lower a sediment sampler into Chicken Creek below.

Chicken Creek in the Tualatin River National Wildlife Refuge. The Refuge has over 200 species of birds and a variety of other wildlife.

USGS hydrologist, Erin Leahy, collects sediment samples at the upstream gage on Chicken Creek in the Tualatin River National Wildlife Refuge.

In March 2025 the streamgage on the Williamson River Near Klamath Agency, Oregon (11493500) recorded significant flow for the first time since March 2020. The aluminum cylinder on the right houses the gage equipment.

A USGS hydrologic technician captured this photo of the Umpqua River near Elkton, Oregon, during a high-flow measurement—the third-highest flow recorded at this gage since it began operation in 1905. View gage data.

Hydrologic technicians captured the powerful high flow of the Umpqua River near Elkton, measuring an impressive 128,000 cubic feet per second on March 17th, 2025. This marks the third-highest flow measured since monitoring began in 1905.

This aerial image was captured during a drone flight for drone-based surface velocimetry, which is a method for measuring the speed of water at the surface of a river or stream using video footage and computer software.

Cow Creek near Riddle, Oregon (1431000): On March 17, 2025, hydrologic technicians captured 14,000 and 13,900 cubic feet per second! These are the 2nd and 3rd highest flow measurements since the period of record began in 1954.

This aerial image was captured during a drone flight for drone-based surface velocimetry, which is a method for measuring the speed of water at the surface of a river or stream using video footage and computer software.

During a routine cleaning, a technician holds up a water-quality sonde to show its sensors. Each sensor measures a different water-quality value, such as temperature or dissolved oxygen. A central wiper helps keep the sensors clean between technician inspections.

Field crew installs sonar equipment on the highway 99W bridge over the Luckiamute River near Parker Oregon. 

The sonar equipment monitors streambed elevation near the bridge footing to measure scour depth. Accurately measuring scour depth is essential for evaluating bridge safety. During short storm events, crews may not arrive in time to monitor in real-time. Without continuous monitoring, the deepest scour could be missed if the hole refills before inspection.

The Tualatin River in Oregon flows approximately 83 miles from the Northern Oregon Coast Range to the Willamette River, providing vital water resources and habitat across the Tualatin Valley.