Images

Researcher preparing to install a mass balance stake on Lemon Creek Glacier using a steam drill.

Walker Lake in Nevada on a Spring day

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.

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-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).

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.

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.

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

A member of the USGS Glen Canyon Adaptive Management Working Group in Flagstaff, Ariz., monitors the Colorado River downstream of Glen Canyon Dam.

A photo taken before the Great Works Dam was removed (likely in 2009), looking upstream from a boat just upstream of the Great Works Dam.

This USGS file photo was taken at a USGS gaging station on the Passadumkeag River at Lowell, Maine (01035000) in 1915. The USGS collected streamflow at this location from 1915 through 1979. The photo shows an unknown hydrographer standing next to a chain gage. The chain gage was used by a local observer to make manual readings of water level. 

Young boys working in a newly cropped field in Africa.

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

Aquatic biologist Tom Sabol of the Grand Canyon Monitoring and Research Center takes samples from the Colorado River.

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

Rush River at Amenia, North Dakota, streamflow 1,650 cubic feet per second,  looking upstream.  Photograph taken during spring 2009 flooding.

The river outlet tubes at Glen Canyon Dam on the Colorado River in Arizona. At noon Monday, Nov. 19, U.S.

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

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

This photo was taken at Station 4 in 2009 before the Great Works Dam was removed. This location was just upstream of the dam and water levels are significantly lower now that the dam is removed.

USGS scientist Jimmy Hopkins takes a streamflow measurement on the Sabine River on March 12 near Bon Weir, Texas.