Images

As the Atchafalaya River spreads out through the Basin, the waters slow down, and the sediment falls to the river and lakebottoms. Over time, that sediment can build up, eventually choking the river or permanently closing the lake. Or, as more and more sediment piles up, it compacts, sinking deeper during a process known as subsidence.

Snow-capped peaks of the La Sal Mountain Range as seen from the Island in the Sky District of Canyonlands National Park. This is one area in the Southwest where biocrust plays an important role. 

USGS scientists Mike Manning (left) and USGS National Flood Coordinator Bob Holmes discuss plans for the day. USGS crews departed from the U.S. Coast Guard's Vicksburg Office on the Yazoo River to measure streamflow on the Mississippi River.

USGS scientist Tammy Caudle demonstrates the acoustic dopplar current profiler onboard that will be used to measure streamflow on the Mississippi River.

Image shows a night-time view of the Natchez-Vidalia Bridge at Natchez, Mississippi.

USGS National Flood Coordinator Bob Holmes stands on one of USGS' boats in Vicksburg, Mississippi. This particular boat came from the USGS Indiana/Kentucky Water Science Center. The boat and its crew joined USGS scientists and boats from Alabama, Louisiana, and Mississippi in Vicksburg for the flood measurements.

This is the Mississippi River at Vicksburg, Mississippi, as the crest from the earlier flooding moves through.

The floodwaters from Arkansas, Illinois and Missouri are making their way downstream now to Mississippi and Louisiana. In preparation, USGS scientist Glen Stevens demonstrates the current meter to Hannah Hamilton, also with USGS. The current meter is one of the two primary ways that USGS measures streamflow discharge.

A panorama of the floodwaters at the Bonnet Carré Spillway. In preparation for the river crests due next week, USGS is out sampling on the Bonnet Carre Spillway, one of two spillways on the Mississippi River operated by the U.S. Army Corps of Engineers.

A staff gage at the Bonnet Carré Spillway, which is managed by the U.S. Army Corps of Engineers.

Mississippi River water flows through the Bonnet Carré Spillway into the channel, where it will flow to Lake Pontchartrain.

Flooded land within the Bonnet Carré Spillway. Normally, this land is dry, but when the U.S. Army Corps of Engineers decides to release Mississippi River water from the Bonnet Carré Spillway, this land will be submerged.

A point sampler for measuring sediment. It has tail fins to orient the sampler so that the intake nozzle in the head points directly into the approaching flow. The sampler head is hinged to provide access to the pint or quart bottle sample container located in a cavity in the sampler body.

A road sign warns drivers to watch for USGS crews measuring streamflow on the Bonnet Carré Spillway during flooding.

A view of the Bonnet Carré Spillway, which is operated by the U.S. Army Corps of Engineers. In this image, floodwaters from the Mississippi River flow through from left to right into the Spillway, eventually bound for Lake Pontchartrain.

A current meter. The rotating silver cups measure how fast the water is flowing. Meanwhile, the black torpedo-shaped object is a weight that keeps the current meter relatively stationary and the fins keep the current meter facing into the approaching flow.

The USGS Streamgage at Baton Rouge, Louisiana, during the 2015/2016 Mississippi River Valley Flooding.

Waves flood across a coastal road near Santa Cruz, California.

Sections of Fashion Valley Road, San Diego, were closed by flooding of the San Diego River. Closed roads were a common scene in San Diego and throughout California during the El Niño-related storms, Jan 6 - 7, 2016. Hydrographers from the Poway Field Office closely monitored high-flow conditions throughout the storms.

Jon Newby and Travis Kordiak, USGS Hydrographers from the California Water Science Center Redlands Field Office, take high-water measurements at USGS streamgaging site 11059300. The site is on the Santa Ana River in San Bernardino, California, and is one of more than 500 streamgage locations in California.

Synthetic surrogate water-hardened Silver Carp Eggs settled on top of a sediment bed. Laboratory experiments in flowing water demonstrate egg suspension at lower velocities than previously thought.