Longitudinal River Monitoring and Modelling Substantiate the Impact of Weirs on Nitrogen Dynamics

Research output: Contribution to journalResearch articleContributedpeer-review

Contributors

Abstract

The fluvial nitrogen dynamics at locations around weirs are still rarely studied in detail. Eulerian data, often used by conventional river monitoring and modelling approaches, lags the spatial resolution for an unambiguous representation. With the aim to address this knowledge gap, the present study applies a coupled 1D hydrodynamic–water quality model to a 26.9 km stretch of an upland river. Tailored simulations were performed for river sections with water retention and free-flow conditions to quantify the weirs’ influences on nitrogen dynamics. The water quality data were sampled with Eulerian and Lagrangian strategies. Despite the limitations in terms of required spatial discretization and simulation time, refined model calibrations with high spatiotemporal resolution corroborated the high ammonification rates (0.015 d −1 ) on river sections without weirs and high nitrification rates (0.17 d −1 ammonium to nitrate, 0.78 d −1 nitrate to nitrite) on river sections with weirs. Additionally, using estimations of denitrification based on typical values for riverbed sediment as a reference, we could demonstrate that in our case study, weirs can improve denitrification substantially. The produced backwater lengths can induce a means of additional nitrogen removal of 0.2-ton d −1 (10.9%) during warm and low-flow periods.

Details

Original languageEnglish
Article number189
JournalWater
Volume14
Issue number2
Publication statusPublished - 10 Jan 2022
Peer-reviewedYes

External IDs

Scopus 85122872321
Mendeley 45e906af-c87e-3eb9-b390-593518535159

Keywords

Keywords

  • Denitrification, Longitudinal river monitoring and modelling, Nitrogen dynamics