Last two paragraphs of your article explain why the EPA is vital...
--In 1969, the Cuyahoga River hit rock bottom with the infamous fire. There was so much oil in the river that it became very flammable. The River became a dead river, meaning it had no oxygen in it. Having no oxygen in the river, made it impossible for any plant or animal life to live. Akron and Cleveland dumped sewage in it, steel and automobile industries caused the river to become one of the worst rivers in Ohio's history.
--The River has made a remarkable recovery. It is known as a success story and an example for other polluted rivers to follow. The 1972 Clean Water Act made many regulations in what could be dumped in the water. The chemistry of the Cuyahoga River has to be good enough to support aquatic life. Many laws have been passed to forbid the sewage from the past of getting into the river. Many years ago Edgewater Beach was closed due to the severe pollution. Edgewater beach is now open to the public today for swimming and picnicking. The Cuyahoga is by no means perfect, but is an example of what could be done to save a very important river.