Measurement

Birds: Information on Salton Sea bird die-offs can be found through the USGS National Wildlife Health Center Web site.   Information has been issued by the center through their Quarterly Wildlife Mortality Report.Fish: There are several species of...
You can view a national map of hardness in surface water at water hardness map. Hardness data (reflecting mostly calcium, plus a little magnesium) for individual drinking-water suppliers can be found at this link EPA Office of Ground Water and Drinking...
Yes, it is not unusual for salt marshes to experience dieback in small patches in some years. However, these areas are usually less than an acre or so in size and generally regenerate the next year or over the next several years. Smooth cordgrass marshes...
Most survey marks were set by the US Coast & Geodetic Survey (now called the National Geodetic Survey) and information for those marks is available on the web. For further assistance call 301-713-3242 or e-mail infocenter@ngs.noaa.gov. If the...
Safe water means water that will not harm you if you come in contact with it. The most common use of this term applies to drinking water, but it could also apply to water for swimming or other uses. To be safe, the water must have sufficiently low...
It is not an easy task to keep a swimming pool so clear and clean. If you just set a pan of water outdoors in the middle of summer, you'll see that it ends up containing gunk very quickly. People have to resort to both chemical and physical means to keep...
Information on pesticides and herbicides and on nutrients is available from the USGS National Water-Quality Assessment Program 
The salinity of Great Salt Lake is measured by taking specific gravity and temperature measurements and comparing them to standardized values reported in a table. Specific gravity is measured in the field by testing a water sample with a device very...
The USGS Grand Canyon Monitoring and Research Center in Flagstaff, Arizona, conducts at least eight trips each year to study endangered fish populations. The USGS is especially interested in the Humpback Chub, but we are interested in all of the fish in...
Since 1950, the U.S. Geological Survey (USGS) has collected and analyzed water-use data for the United States and Territories. The is the main webpage for the USGS Water Use Program. This page is the access point to the water-use data that is assessed...