Images

USGS scientist Joel Stokdyk collects a homeowner water sample in April 2019.

A storm drain that periodically discharges urban runoff, potentially carrying sediment and pollutants, into Oak Creek at 15th Avenue near a USGS gage.

USGS hydrologist Erich Kessler prepares to measure the stream stage (the height of the water surface) of the Middle Fork Crow River near Spice, Minnestota.

Chippewa Dunes Multibeam Survey downstream of Durand bridge.

Bank erosion along an upstream reach of the Kinnickinnic River, October 2018.

Scientists collecting water samples for mercury isotope analysis in the Mobile River, Alabama.

Two single-frequency ADVMs mounted to Durand bridge.

Two white-tailed bucks (deer) looking at the camera at Lake of the Ozarks, Missouri.

Close-up view of defined area of a rock cobble (middle) where attached algae and other material were removed with a brush. Rocks from multiple locations at a site are composited into a single sample representing the stream site.

Panoramic view of scientists in boat on Hells Canyon Reservoir, Idaho

After collection, invertebrates are washed through a series of sieves where large debris can be removed before being placed in the sample bottle.

USGS scientist collecting one of five subsamples of aquatic invertebrates from a stream riffle by removing invertebrates from a defined area and collecting them with a Surber net. Each subsample is transferred to a bucket for compositing into a single sample for the site.

Scenic view while preparing to launch boats at Anderson Ranch, at the Anderson Reservoir, Idaho.

Close up-view of defined area of the stream bottom where attached invertebrates are removed with a brush and washed into the Surber net; where possible, a hand rake is also used to dislodge organisms from shallow depths.

USGS scientist removing attached algae from a defined surface area on one of multiple rocks collected in riffles at a stream site.

Flow-through sensor for measurement of three different optical signals.

Human-specific virus filtration units with 10-micron nominal pore size string-wound pre-filter and dead-end ultrafilter after a five-day composite sampling event with the Menomonee River in background. Menomonee River at 16^th St. in Milwaukee, Wisconsin.

Ultrafilters are used to concentrate pathogens from large-volume surface water samples. Plastic autoclaved bottles used for human-associated indicator bacteria analysis. Glass bottle used for DOC, simultaneous fluorescence and absorbance, and pharmaceutical compound analysis.

Photograph of a 24-bottle automatic sampler to collect water samples for optical properties of water and microbiological analyses.

Prefilter and Ultrafilter assembly from Menomonee River at 16th St., Milwaukee, WI.

Particulate matter captured on a quartz fiber filter at the Mercury Research Laboratory.