Hydrological mediated denitrification in groundwater below a seasonal flooded restored riparian zone

TY - JOUR

T1 - Hydrological mediated denitrification in groundwater below a seasonal flooded restored riparian zone

AU - Jensen, Jannick Kolbjørn

AU - Engesgaard, Peter

AU - Johnsen, Anders R.

AU - Marti, Vicens

AU - Nilsson, Bertel

PY - 2017/3/1

Y1 - 2017/3/1

N2 - A restored riparian zone was characterized to understand the effects of flooding on subsurface hydrological flow paths and nitrate removal in groundwater. Field and laboratory investigations were combined with numerical modeling of dynamic flow and reactive nitrate transport. Flooding enhances nitrate removal in groundwater primarily by two mechanisms. First, by creating a stagnant flow zone beneath the flooded area thereby increasing the residence time and leaving more time for nitrate removal. Secondly, nitrate removal is increased by enhancing upward flow into the highly reactive organic-rich top layers. Flooding therefore contributes to nitrate removal in "hot spots", where nitrate is transported to the peat and during "hot moments", when flow is stagnant. The permeability of the capping peat layer relative to the aquifer is important as it controls both mechanisms. The model shows that the deep-seated nitrate removal is greater than projected from the laboratory nitrate reduction experiments.

AB - A restored riparian zone was characterized to understand the effects of flooding on subsurface hydrological flow paths and nitrate removal in groundwater. Field and laboratory investigations were combined with numerical modeling of dynamic flow and reactive nitrate transport. Flooding enhances nitrate removal in groundwater primarily by two mechanisms. First, by creating a stagnant flow zone beneath the flooded area thereby increasing the residence time and leaving more time for nitrate removal. Secondly, nitrate removal is increased by enhancing upward flow into the highly reactive organic-rich top layers. Flooding therefore contributes to nitrate removal in "hot spots", where nitrate is transported to the peat and during "hot moments", when flow is stagnant. The permeability of the capping peat layer relative to the aquifer is important as it controls both mechanisms. The model shows that the deep-seated nitrate removal is greater than projected from the laboratory nitrate reduction experiments.

KW - Denitrification

KW - Flooding

KW - Hot moments

KW - Hot spots

KW - Riparian zones

U2 - 10.1002/2016WR019581

DO - 10.1002/2016WR019581

M3 - Journal article

AN - SCOPUS:85015201475

SN - 0043-1397

VL - 53

SP - 2074

EP - 2094

JO - Water Resources Research

JF - Water Resources Research

IS - 3

ER -