The United States Geological Survey (“USGS”) announced on April 4th an interactive map which is described as a “comprehensive, long-term look at changes in the quality of our nation’s rivers and streams over the last four decades.”

The map was developed by the USGS National Water-Quality Assessment Project.

USGS states that this endeavor conducts regional and national assessment of the nation’s water quality to provide an understanding of current water-quality conditions, whether conditions are getting better or worse over time, and how natural processes and human activities affect those conditions.

The agency notes that it is the first time that the monitoring data that it and 73 other organizations collect (at 1,400 sites) have been combined to provide a nationwide look at changes in the quality of rivers and streams between the enactment of the Clean Water Act (in 1972) and 2012.

The map can be utilized to determine whether 51 water-quality constituents and 38 aquatic-life metrics have increased, decreased, or remained the same at nearly 1,400 sites between 1972 and 2012. Examples cited are the types and numbers of fish, macroinvertebrates, and algae. An example of the potential use is the phaseout of the insecticide diazinon for residential and some agricultural uses that was initiated in 2000. USGS states that this phaseout has led to widespread reductions in concentrations in United States streams, which can be seen on the interactive map during the trend period from 2002 to 2012.

A link to the interactive map can be found here.