Water

Stream stage (aka gage height) is an important concept when analyzing how much water is moving in a stream at any given moment. "Stage" is the water level above some arbitrary point in the river and is commonly measured in feet. For example, on a normal day when no rain has fallen for a while, a river might have a stage of 2 feet. If a big storm hits, the river stage could rise to 15 or 20 feet...

At some USGS streamgage installations, NOAA’s National Weather Service (NWS) maintains a separate stage sensor that is serviced by NWS technicians. Calibration of any sensing device can occasionally drift from a "true" value, so there might be differences between USGS and NWS data reports. USGS personnel visit installations on an interval of 6 weeks or less to maintain equipment and make required...

In order to convert gage height (or "stage", usually expressed as feet) into streamflow (or "discharge", usually expressed as cubic feet per second), USGS hydrographers must establish a relationship between them. This stage-discharge relationship is called a rating curve. It’s developed by making frequent manual discrete discharge measurements at stream gaging stations. The rating curve depends on...

Real-time USGS streamflow data are PROVISIONAL, meaning that the data have not been reviewed or edited. These data might be subject to significant change and are not official until reviewed and approved by the USGS. Real-time streamflow data can be affected by: backwater from ice or debris such as log jams algae and aquatic growth in the stream sediment movement malfunction of recording equipment...

There can be occasional equipment or database problems where erroneous data are reported for short periods of time until corrections can be made. This is why it is important to look at a record of streamflow (like the 7-day hydrograph plots) rather than a single point in time. However, most of the time the USGS has a high level of confidence in its real-time stage data. During low streamflow...

USGS real-time streamflow data are typically recorded at 15-minute intervals, stored onsite, and then transmitted to USGS offices once every hour, depending on the data relay technique used. Recording and transmission times might be more frequent during critical events (floods, for example). Data from current sites are relayed to USGS offices via satellite, telephone, and/or radio telemetry and...

The best starting point for USGS streamflow data is the interactive National Water Information System (NWIS): Mapper website. Zoom in to your area of interest or use the search options in the left navigation window. The map displays active surface-water sites by default, but you can change the type of water site (surface-water, groundwater, springs, atmospheric) and select to show inactive sites...

The USGS usually corrects any equipment or station problems at our streamgages within a few days of their occurrence. Occasionally, replacement parts or equipment might not be readily available, or a station might be inaccessible due to weather conditions. Most USGS streamgaging stations are operated in cooperation with other agencies. At some stations, the stage transmitting equipment is owned...

Information on the flow of rivers is a vital national asset that safeguards lives, protects property, and ensures adequate water supplies for the future. The USGS is the federal agency responsible for operating a network of about 7,000 streamgages nationwide. Data from this network are used by water managers, emergency responders, utilities, environmental agencies, universities, consulting firms...

Some counties offer free well water testing, so check with your county first. If they don't, use this EPA website to find a list of state-certified laboratories in your area that do water testing, or contact your county or state health department or your State Certification Officer for assistance. Prices will vary depending on the laboratory and the test(s), but most people consider the cost to be...

Devils Hole is a tectonic cave developed in the discharge zone of a regional aquifer in south-central Nevada. The walls of this predominantly subaqueous (underwater) cavern are coated with dense vein calcite that precipitated from groundwater moving through the cavern. The stable isotopic content of the calcite provides a 500,000-year record of variations in temperature and other climate...

A confined aquifer is an aquifer below the land surface that is saturated with water. Layers of impermeable material are both above and below the aquifer, causing it to be under pressure so that when the aquifer is penetrated by a well, the water will rise above the top of the aquifer. A water table--or unconfined--aquifer is an aquifer whose upper water surface (water table) is at atmospheric...