Wednesday, April 05, 2017

The Water Quality of US Streams & Rivers

A new interactive map from the USGS allows you to see whether the water quality of US streams and rivers has improved or decreased over the last few decades. The Water-Quality Changes in the Nation's Streams and Rivers map shows water quality trends in waterways since the beginning of the 1970's.

The colored arrows on the USGS map show which streams and rivers have improved in water quality and which have decreased. You can select to see the water quality changes over four different periods of time using the controls in the map sidebar.

The water quality of the country's streams and rivers are assessed in a number of different constituent groups. These are: water chemistry (nutrients, pesticides, sediment, carbon, and salinity) and aquatic ecology (fish, invertebrates, and algae). You can see how stream and river water quality has changed in each of these groups by selecting them from the side panel.

You can also see how groundwater quality has changed over the decades on another USGS interactive map. About half of the U.S. population relies on groundwater for drinking water. The United States Geological Survey is responsible for the National Water Quality Assessment Project, assessing water-quality conditions and whether these conditions are improving or deteriorating over time.

The results of these changing conditions are available in the USGS interactive map, A Decadal Look at Groundwater Quality. The map shows the concentrations of pesticides, nutrients, metals, and organic contaminants in groundwater and how these have changed over ten years.

Using the map you can select to view the test results for a large number of organic and inorganic constituents. Scaled arrow markers on the map indicate whether the tested aquifers showed an increase or decrease in the selected constituent between the decadal testing. For example, if you select to view the results for chlorine, the arrow markers on the map show that most wells tested have shown an increase in chlorine over the ten years between the two latest tests.
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