Many investigations in coastal plain riparian soils have highlighted the importance of wetlands in removing nitrate from shallow groundwater.

However, few studies have measured the nitrate removal function of riparian soils in narrow Appalachian valleys of the eastern US. We used shallow groundwater monitoring wells and denitrification enzyme activity measurements to demonstrate significant nitrate removal in riparian wetlands receiving nitrified wastewater effluent. While these riparian wetland soils provided significant water quality functions by removing nitrate, drier soils close to the small headwater stream were not significant sinks for nitrate. Our results suggest that the nutrient removal functions of narrow riparian zones in the Appalachian region do not extend to the entire riparian zone.

Roaring Run

Roaring Run, a typical hemlock-lined headwater stream in an Appalachian valley of Pennsylvania.

water sampling

Bart Kirk, an undergraduate research assistant, collects a water sample discharging to the riparian zone.

riparian wetland

Shallow riparian wetland along Roaring Run.


The nitrate removal potential, as measured by denitrification enzyme activity, was highest in the A-horizon soils of the riparian wetlands.