Co-Authors: S. McMillan, G. Noe, S. Donohue
Restoration of impaired and hydrologically disconnected floodplains is seen as having great promise for alleviating water quality concerns in river corridors given the capacity of floodplains to remove inorganic nitrogen from surface water and groundwater via denitrification. Despite high investment into floodplain restoration, little is known about how different restoration strategies and designs impact denitrification rates. Our research fills this gap by linking denitrification to the environmental factors that can incorporated into restoration design. We measured denitrification potential across hydrologic and geomorphic gradients and across levels of restoration intervention in riverine floodplains in the agricultural Midwest. Simultaneously, we measured environmental factors, such as soil and hydrologic characteristics, to elucidate environment factors that are predictive controls of denitrification. Preliminary findings suggest that vegetation type and hydrologic regime are strong controls of denitrification capacity and high levels of subsurface connectivity are necessary to restore denitrification capacity. Our findings will aid watershed managers and regulatory agencies in identifying floodplains that will likely exhibit high denitrification upon restoration and will assist practitioners to develop future floodplain designs that maximize water quality benefits.