Images

Beaver dam complex and lodge at the confluence of Wrench Creek and Kelly River, Noatak National Preserve

Black Racer snake (A) The epidermis over much of the body, but cranially pronounced, has multifocal to coalescing dull white to pale gray foci. (B) Multiple scales around the head are thickened and roughened. (C) Ventrally, there are multiple dull white to grey foci of up to 8 mm size, occasionally with central indentations.  

Dee-Ann McCarthy (USGS) measuring low flow in picturesque New England fall foliage at stream gage 01118300 Pendleton Hill Brook near Clarks Falls, CT.

Image of North Taylor Creek in Wet Mountain Valley, Colorado prior to completion of a surface-water discharge measurement.

A science crew on M/V (marine vessel) Bold Horizon retrieve gear from offshore San Francisco.

A panoramic view of the Columbia River and Miller Island near the eastern end of the Columbia River Gorge National Scenic Area. The island and cliff walls on both sides of the Columbia River are composed of stacked lava flows of the Columbia River Basalt Group. 

The Natural Water Cycle

Locations of the July 2019 earthquake epicenters and six USGS groundwater-monitoring sites.

USGS scientists on the back deck of M/V Bold Horizon in San Francisco Bay: (back row, standing: left to right) Brandon Nasr, Danny Brothers, Travis Alonghi (USGS student contractor), Gerry Hatcher, Jenna Hill, Pete Dal Ferro, and Jenny McKee; (front row, kneeling: left to right) USGS scientists Janet Watt and Nora Nieminski.

USGS science crew from Pacific Coastal and Marine Science Center work together to get the vibracorer coring device in position to collect sediment core samples off San Francisco, California.

The Rossfelder P-5 vibracorer, with its polybuterate liner visible, is secured on the deck of the research vessel Bold Horizon, awaiting deployment off the coast of California just north of San Francisco. More liners are stored in a cage off to the side.

The USGS uses the Rossfelder P-5 vibracorer to collect deep-water sediment samples from the seafloor. Here, they are heading out offshore of San Francisco with the Golden Gate Bridge in the background.

The Ben Franklin Bridge stretches over the Delaware River. The Delaware River Basin provides water to big cities such as New York and Philadelphia. 

USGS scientists collect gas from the Puhimau thermal area on Chain of Craters Road in Hawai‘i Volcanoes National Park. The gas is collected in evacuated (vacuum-pumped so that no gas at all is inside) glass bottles, and a system of a syringe with tubing helped ensure minimal contamination by ambient atmospheric gases.

USGS scientists collect gas from the Puhimau thermal area on Chain of Craters Road in Hawai‘i Volcanoes National Park. The gas is collected in evacuated (vacuum-pumped so that no gas at all is inside) glass bottles, and a system of a syringe with tubing helped ensure minimal contamination by ambient atmospheric gases.

Adult Pacific salmon (Oncorhynchus nerka) caught in impounded water above beaver dam. >25 rKM (river KM) from coast.

U.S. Geological Survey hydrologic technician Mike Michelotti measures streamflow on the South Fork Coeur d'Alene River at Elizabeth Park near Kellogg, Idaho, October 9, 2019. The USGS operates streamgage station 12413210 in cooperation with the U.S. Environmental Protection Agency.

Mike Michelotti is making a winter stream flow measurement using a flow tracker at stream gage 12413210 South Fork Coeur D' Alene River at Elizabeth Park near Kellogg, ID.

USGS staffer Matthew Jennings collecting water quality samples on the lower Niagara River for the Great Lakes Restoration Initiative (GLRI) project. Photo by John Wernly (Public domain)

什么是水循环？

什么是水循环？回答这个问题非常容易 ---水循环通常也被称为"水分循环"或"水文循环"，是指水在地球上、地球中以及地球上空的存在及运动情况。地球的水处于不停地运动中，并且不停地变换着存在形式，从液体变成水蒸气再变成冰，然后再循环往复。水循环已经持续了几十亿年，地球上的所有生命都依赖于水循环。如果没有水循环，地球将会是一个毫无生气的地方。

El Ciclo del Agua