Boone Lake is a 4600 acre reservoir in Upper East Tennessee near the cities of  Bristol TN/VA, Elizabethton TN, and Johnson City, TN.  It is part of a series of man-made lakes built and operated by the Tennessee Valley Authority for flood control, navigation, and hydro-power generation.   Since its construction in the early 1950's,  water quality has been an issue.  In fact, in its early years there was skepticism about the lakes ability so support any kind of fishery. As one writer observed in 1954:

"Well, how will the fishing be in Boone?  A good question, but we still don’t have any good answer.  Boone looks like any other east Tennessee reservoir, but in this case looks are deceiving.  Yes, there are fish in Boone, but .... .  Why the skepticism?  Well, frankly, the reservoir is polluted to the gills -- figuratively and literally." 
Boone Lake -- Fish vs. Pollution by  C.J. Chance and M. A. Churchill

While population and industrial activity continued to grow,  the cities and industry began large-scale efforts to control pollution.   By the 1970's, major point sources were under control and incidences of gross pollution were largely eliminated.  The lake became an important asset to the region, providing recreational opportunities and encouraging extensive development of the shoreline for homes and businesses.
By the early 1980's Boone appeared to be in reasonably good condition.

But appearances can be deceiving!

In 1983, a series of incidents pointed out that progress is reversible.  Floating sewage sludge appeared on the surface of the lake.    Investigations showed that large volumes of sludge had accumulated in the lake as a result of inadequate sludge handling  at one major waste discharge.  Bacteria levels far exceeded recreational standards.  Further investigation showed problems at other wastewater plants.  Some sewer systems were overloaded due to combined sewer problems.

Since then, great improvements in water quality have been made. The single greatest improvement came as a result of the 1988 Clean-water Act which mandated the separation of storm and sanitary sewer systems. This resulted in over $40M dollars of upgrades in local sewer systems and had a tremendous impact on the water quality of Boone Lake. The formation of regional TDEC office in Johnson City in the mid- I980's has also proved beneficial. Through the efforts of the Boone Watwershed Partnership, the Boone Lake Association, the cities of Johnson City, Elizabethton and Bristol and TDEC, Boone Lake is safe enough to swim, boat and fish in.