Draining the landscape: how do nitrogen concentrations in riparian groundwater and stream water change following milldam removal?

350 210 Stroud Water Research Center

Lewis, E., S. Inamdar, A.J. Gold, K. Addy, T.L.E. Trammell, D. Merritts, M. Peipoch, P.M. Groffman, J. Hripto, M. Sherman, J. Kan, R. Walter, and E. Peck. 2021. Journal of Geophysical Research Biogeosciences 126(8), e2021JG006444.


Dams are being removed to allow fish passage and improve safety for water users. Dam removal results in a drop of stream water level and a drying-out of the streamside (riparian) zones. We investigated if these changes would undermine the N-filtering service of riparian zones and increase N concentrations in groundwater and stream waters. We monitored soil and water N concentrations for two years following the removal of a 1.5 m milldam on Chiques Creek in Pennsylvania. Our data showed that while denitrification in soils did decrease, the N concentrations in riparian groundwaters and stream waters did not increase over the study period.