Issue 5

Riparian Zones:
How Wide Is Enough?

by Kim MacQueen

You’re doing well if you can get a preponderance of the South’s forest managers to agree on something. It’s that way with riparian zones, the areas alongside forest streams, rivers, and lakes that filter sediments and help keep water clean. Sometimes called streamside management zones (SMZs), riparian forests, or forest filter strips, riparian areas are critical to overall water quality and forest health.

Their benefits are numerous: Trees and other vegetation growing in riparian zones (from the Latin ripa, meaning bank) provide cool, shady habitat for fish such as trout while they trap phosphorus, nitrogen, and toxins in their roots and leaves. Fallen leaves, wood debris, and vegetation provide food and habitat for forest animals, which also use streamside forests as travel corridors.

For decades—but especially since the Clean Water Act of 1977—scientists, forest managers, and much of the public have understood the need to keep pollution from entering streams. Anywhere on forested lands, and in particular wherever roads cut through, SMZs are essential to reduce watershed contamination. SMZs are the last chance to keep herbicides, oil and grease from vehicles and machinery, sediment from eroding streambanks, or scores of other contaminants out of the water supply. (...continued...)