Images

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.

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

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

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

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.

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.

USGS Hydrologist Travis Smith makes a wading (section-by-section) discharge measurement at Moyer Creek stream gauging station near Frankfort,  NY  to allow for better estimates of streamflow during ice-affected periods in winter.

Walker Lake in Nevada on a Spring day

Coal-tar-based sealcoat is a potent source of PAHs and related chemicals. Worn particles of coal-tar-based sealcoat are transported by rain, wind, tires, and even our feet from pavement to other environmental settings. Sealcoat product (A), after it dries, gradually abrades to a powder and becomes part of the dust on the pavement (B).

Concentrations of polycyclic aromatic hydrocarbons (PAHs) in settings near pavement sealed with coal-tar-based sealants were substantially higher than concentrations in settings where coal-tar sealant was not used.

Coal tar is a byproduct of the coking, liquefaction, or gasification of coal. Coal-tar pitch is the residue that remains after the distillation of coal tar. Coal tar and coal-tar pitch are used in coal-tar-based sealcoat products, although use of coal-tar pitch is more common than use of coal tar. Both coal tar and coal-tar pitch are known human carcinogens.

Cool, clear rivers of the Texas Hill Country attract visitors for many recreational opportunities. Here, a family enjoys paddleboarding at Schreiner Park during spring break in Kerrville, Texas.

H.D. McGlashan measures streamflow in the Merced River, circa 1920. Multiple velocity and water-depth measurements along a stream cross section are used to calculate the total volume of water passing a certain location over a specific period of time (cubic feet per second).

Location: Merced River, Yosemite National Park, California

Soper Branch stream with a USGS streamgage on the bridge. Soper Branch is a small stream near Hyattstown, MD, that is part of the Chesapeake Bay watershed.

The outlet tubes of Glen Canyon Dam were opened during the 2004 high-flow experiment on the Colorado River. 

A frosty day in North Dakota near the Hear River above Lake Tschida, near Glen Ullin, streamgage.

Young boys working in a newly cropped field in Africa.

A herder moves cattle through a barren landscape in eastern Africa.

A Food Security Assessment in Somalia found severe impacts on livestock due to drought conditions.