It's not that long ago. I live near by what used to be one of the dirtiest waterways in the the US. Even as recently as the mid-90s, sewage was dumped directly into the waterway and numerous landfills seeped toxic chemicals such as lead and various hydro-carbons into it. The river used to be so toxic that no life beyond worms could inhabit it.

The cleanup for it started in 2006 and is ongoing today. It's only within the past decade that fish finally started swimming in the river. And now the neighborhoods that it runs through are seeing huge increases in property values and new development as this former toxic waste dump is now converted into water-front bike trails and parks.

We absolutely still see the benefits of the Clean Water Act today.