Images

Alaska Volcano Observatory scientist Mark Hansen working with Larsen Bay Mayor David Harmes on how the AVO-4 particulate monitor operates.

Murals on the USGS Western Fisheries Research Center Pump House structure by Jeff Jacobson. 

Interpretive signage created by interpretive designer and illustrator Denise Dahn, with murals of USGS Western Fisheries Research Center Pump House created by Jeff Jacobson in background.

Murals on the USGS Western Fisheries Research Structure Pump House structure by Jeff Jacobson. 

Looking upstream from gage site at Trinity River at Commerce Street Bridge.

Modern-day USGS streamgage at Elm Fork Trinity River near Carrollton, Texas.

A modern 21^st century version of a streamgage structure.

Nearly completed construction of a streamgage structure in 1955 at Elm Fork Trinity River near Carollton, Texas.

This 1922 photo shows an early USGS streamgage on the Trinity River in Dallas.

Aspen trees at the Reynolds Creek experimental watershed in Idaho.

Currently, most of the streamflow equipment is located on a streambank or bridge. Large structures are no longer needed at most streamgage locations. Today, streamgage equipment can be contained in small metal shelters that are located on streambanks or bridges.

This 2014 photo shows the new location of the USGS streamgage that measures high flows on the Trinity River in Dallas. The gage was once located on a pier, but in 1975 was moved next to the stream. 

Construction in 1939 of a streamgage structure at Elm Fork Trinity River near Carrollton, Texas.

One of the oldest versions of a streamgage structure constructed in Texas.

A close-up view of the top part of one of the oldest streamgage structures constructed in Texas.

In the earlier years of streamgaging, large “stilling wells” were constructed to contain the equipment needed to collect streamflow data. Historically, most of the streamflow equipment may have been located in these large structures, which were placed in the middle or next to the stream.

Photomicrograph of gabbroic inclusion in Ogres Brow basaltic andesite. A rock thin section is created by gluing a small piece of rock onto a glass slide, then grinding it down to a thickness of 30 microns (the average human hair is about 100 microns in diameter) so that light shines through it when examined under the microscope.

USGS scientists conduct a post-construction assessment of the Cottrellville Shoreline Restoration Project on the St. Clair River, Michigan.

Between 2011 and 2013 USGS researchers from Patuxent Wildlife Research Center sampled fish, osprey eggs, and osprey chicks' blood plasma at multiple sites in Chesapeake Bay to track the movement of certain pollutants through the Bay food chain. These hatchlings are just a few days old.

Walker Lake in Nevada on a Spring day

Varied thrush at the HJ Andrews Experimental Forest in Oregon.