The Monongahela River Is Getting Healthier, but Still Bears a Heavy Burden From the Past

The Monongahela River is a 130-mile waterway that begins in the mountains of West Virginia and ends in Pittsburgh, where its waters flow into the Ohio River. Over the course of that journey, the river winds through some of the most heavily industrialized lands in American history.

Though heavy industry has ebbed along its banks in recent years, the Mon still bears the scars of the region’s heritage as America’s workbench. So how polluted is the Mon? And what pollutants does its water carry?

Clean or Dirty?

When it meets the Allegheny to form the Ohio River in Downtown Pittsburgh, the Mon is often brownish-looking while the other rivers are green to blue. Does that mean the Monongahela is dirtier than the others? Why is the Monongahela so brown?

The color of the Monongahela actually has nothing to do with how dirty or how clean it is. Paul Ziemkiewicz, former director of the West Virginia University Water Research Institute, said the color derives from the river’s unique geology. The Monongahela River is one of two large rivers in North America that flows north. (The other is the Mackenzie in northern Canada.)