Episodes 2019; 42(4): 333-341
Published online December 1, 2019
Copyright © International Union of Geological Sciences.
Haoyu Zhu1,3,4, Dongsheng Liu1,2,3*, Wenqing Shi1,3, and Qiuwen Chen1,3
1State Key Laboratory of Hydrology-Water Resources & Hydraulic Engineering, Nanjing Hydraulic Research Institute, Nanjing 210029, China
2College of Water Conservancy and Hydropower Engineering, Hohai University, Nanjing 210098, China
3Center for Eco-Environmental Research, Nanjing Hydraulic Research Institute, Nanjing 210098, China; *Corresponding author, E-mail: firstname.lastname@example.org
4School of River and Ocean Engineering, Chongqing Jiaotong University, Chongqing 400074, China
Correspondence to:*E-mail: email@example.com
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By using a 2D-coupled flow and solute transport and reaction model across the stream-to-riparian continuum, this paper systematically studied the nitrogen-cycling processes driven by a flood wave and their spatial-temporal distributions. The influences on hyporheic nitrogen removal of different waves that vary by amplitude (A), duration (T), wave-type parameter (r) and rising duration (tp) were investigated. During the surface-water-infiltration period, the aerobic respiration, nitrification and denitrification in the hyporheic zone were gradually enhanced, and aerobic respiration was dominant. During the groundwater-backflow period, the reactions gradually weakened, and the role of denitrification was improved. The consumption of each solute continuously increased in the whole process, and the groundwater-backflow period corresponded to a larger consumption but at a smaller consumption rate. The reaction rates in space from high to low were as follows: riparian phreatic zone > variable saturated zone > stream bed. Hyporheic nitrogen removal increased with increasing A, T and tp and with decreasing r, which was contrary to the change rule of nitrogen removal efficiency. The hyporheic nitrogen removal exhibited a good linear relationship with the polynomial ‘A*T*tp/r’, which had great predictive significance.