High‐resolution spatiotemporal analysis of hydrologic connectivity in the historical floodplain of straightened lowland agricultural streams

Marchand, Jean‐Philippe; Biron, Pascale; Buffin‐Bélanger, Thomas et Larocque, Marie (2022). « High‐resolution spatiotemporal analysis of hydrologic connectivity in the historical floodplain of straightened lowland agricultural streams ». River Research and Applications, 38(6), pp. 1061-1079.

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Résumé

In agricultural watersheds, human interventions such as channel straightening have disrupted the hydrologic connectivity between headwater streams and their riparian environment and have thus undermined the ecological services provided by these small streams. Knowledge of the hydrologic connectivity between these streams and their immediate environment (shallow riparian groundwater in the historical floodplain and on adjacent hillslopes) in human-impacted settings is critical for understanding and restoring these hydrological systems but remains largely incomplete. The objective of this research is to investigate the hydrogeomorphological conditions controlling hydrologic connectivity in the historical floodplain of straightened lowland streams. Detailed measurements on the spatiotemporal variability of groundwater-surface water interactions between straightened reaches, historical floodplain including abandoned meanders, and the adjacent hillslopes were obtained using a dense network of piezometers at two sites in the St. Lawrence Lowlands (Quebec, Canada). Results show that the complex mechanisms controlling hydrologic connectivity in naturally meandering lowland rivers also operate in highly disturbed straightened reaches, despite backfilling and agricultural practices. The pre-straightening hydrogeomorphological configuration of the floodplain partly explains the complex patterns of piezometric fluctuations observed at the sites. The apex of the abandoned meanders stands out as a focal area of hydrologic connectivity as water levels indicate pressure transfer that may reflect flows from the stream, the hillslopes, and the surrounding historical floodplain. These unique field observations suggest that abandoned meanders should be promoted as key elements of restoration strategies in lowland agricultural straightened headwater streams.

Type:	Article de revue scientifique
Informations complémentaires:	This is the pre-peer reviewed version of the following article: Marchand, J.-P., Biron, P., Buffin-Bélanger, T., & Larocque, M. (2022). High-resolution spatiotemporal analysis of hydrologic connectivity in the historical floodplain of straightened lowland agricultural streams. River Research and Applications, 38( 6), 1061– 1079. which has been published in final form at https://doi.org/10.1002/rra.3990. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions.
Mots-clés ou Sujets:	abandoned meander, channelized agricultural headwater stream, floodplain, groundwater,hydraulic head, stream restoration
Unité d'appartenance:	Faculté des sciences > Département des sciences de la Terre et de l'atmosphère
Déposé par:	Marie Larocque
Date de dépôt:	29 août 2022 13:28
Dernière modification:	29 août 2022 13:28
Adresse URL :	http://archipel.uqam.ca/id/eprint/15783

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