The phrase "water quality" refers to a number of things about water that we can measure and which affect how safe the water is for us to drink or swim in and how safe it is for fish and other animals to live in. Adding things to water by channeling runoff into a stream or by emptying waste into the water, or even natural things like the water dissolving the rocks and soil it runs over, can affect--for good or bad--water quality.

One thing we measure is fecal coliform, a particular type of bacteria that can be present in water when human or animal waste is in the water. The map below shows graphs of the amount of fecal coliform in the Altamaha River at different sampling stations and at different times from 1974 until 1997. The red bars at the left of each small graph represent the amount of fecal coliform present in 1974. As you can see, the numbers have declined at all but the lowest station on the river, where a campground was built.