Images

The USGS Southwest Gravity Program carries out gravity projects for aquifer-storage monitoring and geologic modeling in California, Arizona, and New Mexico. This map shows the location of 24 projects carried out since 2010.

As generalized in this image, a gravity measurement is sensitive to a cone-shaped region of the subsurface—as depth increases, the sensitivity to individual water molecules decreases, but the region of sensitivity expands.

Line graph showing modeled continuous dissolved-solids concentration and sampled dissolved-solids concentration at station 09522005 (Colorado River below Cooper wasteway near Yuma, Arizona) and streamflow at station 09522000 (Colorado River at NIB, above Morelos Dam, Arizona) from January 2017 to March 2019.

Map of study area and location of data collection sites in the Yuma, Arizona, area between Imperial Dam and the southerly international boundary between the United States and Mexico,

This is an image of an extensometer well part of the Tucson Extensometer Well Network. This well is located in Avra Valley, AZ.

Flooding at Vekol Wash today, south of Phoenix, following remnant rains from Hurricane Rosa. 

Small Unmanned Aerial System (UAS) collecting digital photos to create digital elevation models. UAS are an increasingly important tool for monitoring, assessing, and conducting targeted scientific research for the nation.

Chart showing changes in vegetation density in the Mississippi River delta in Louisiana, May 2015-May 2016. From a USGS Open File Report published in July 2017 by co-authors Elijah Ramsey III and Amina Rangoonwala,

Colorado River at Imperial Dam northeast of Yuma, Arizona. Gates in the foreground supply Colorado River water to desilting ponds before being diverted to the All American Canal.

Photograph showing San Pedro Riparian National Conservation Area, residential development southeast of Sierra Vista, Arizona, and the Huachuca Mountains from Hereford Road, Cochise County, Arizona. 

The turbid waters of the Elwha River and the coastal waters of the Strait of Juan de Fuca mix directly offshore of the river mouth, forming a large coastal plume.  This plume is easily identified by the cloudiness of the water (or "turbidity") resulting from sediment discharged by the river.  Two large dams on the Elwha River are being incrementally r

The turbid waters of the Elwha River and the coastal waters of the Strait of Juan de Fuca mix directly offshore of the river mouth, forming a large coastal plume.  This plume is easily identified by the cloudiness of the water (or "turbidity") resulting from sediment discharged by the river.  Two large dams on the Elwha River were incrementally r

Flood-alert instrument tower with electronics shelter and precipitation gage at top of tower.

Electronics inside the instrument shelter, which includes a high-data-rate transmitter (upper right) and line-of-sight receiver (middle left). The line-of-sight receiver picks up transmissions from the remote rain gage at the look-out area at the top of the Montezuma Pass, Arizona.

Remote rain gage affixed to the roof line of a building at the top of Montezuma Pass, Arizona.

USGS divers Steve Rubin and Reg Reisenbichler laying out a survey transect in the Elwha River in northern Washington.

The Colorado River Basin showing the location of Lees Ferry, Glen Canyon Dam, and the Lees Ferry and other U.S. Geological Survey gaging stations (with station numbers) used in this study. Modified from Topping and others, 2003.

September 21, 1923, 9:00 a.m. --- Colorado River at Lees Ferry. From right bank on line with Klohr's house and gage house. Old "Dugway" or inclined gage shows to left of gage house. Gage height 11.05', discharge 27,000 cfs. Lens 16, time =1/25, camera supported. Photo by G.C. Stevens of the USGS. Source: 1921-1937 Surface Water Records File, Colorado R.