Stream water continuously enters and exits streambed material because sediments are permeable and because of the presence of near‐bed pressure gradients. These fluxes, known as hyporheic fluxes, deliver surface water with its constituents, i.e. temperature and solutes, to the streambed environment, where reactive e solutes undergo biogeochemical reactions. These transformations depend on the amount of water downwelling into and the residence time of surface water within the hyporheic zone. They cause physicochemical gradients, which sustain a rich ecotone, and affect the quality of both surface and subsurface waters. Here, we present a set of analytical solutions to predict the mean hyporheic downwelling fluxes and the hyporheic residence time distribution induced by the interaction between stream flow and two important bedforms: dune‐like and pool‐riffle. We also introduce two dimensionless numbers to characterize the hyporheic zone redox and thermal conditions at the bedform scale. These numbers are easy to quantify because they are derived by commonly measured reach‐scale hydromorphological stream data, which include hydraulic depth, mean flow velocity, mean streambed slope and streambed grain size distribution.

Modeling Surface-Subsurface Exchange of Heat and Nutrients / Tonina, D.; Marzadri, A.; Bellin, A.. - ELETTRONICO. - (2017), pp. 235-260. [10.1002/9781118971437.ch9]

Modeling Surface-Subsurface Exchange of Heat and Nutrients

D. Tonina;A. Marzadri;A. Bellin
2017-01-01

Abstract

Stream water continuously enters and exits streambed material because sediments are permeable and because of the presence of near‐bed pressure gradients. These fluxes, known as hyporheic fluxes, deliver surface water with its constituents, i.e. temperature and solutes, to the streambed environment, where reactive e solutes undergo biogeochemical reactions. These transformations depend on the amount of water downwelling into and the residence time of surface water within the hyporheic zone. They cause physicochemical gradients, which sustain a rich ecotone, and affect the quality of both surface and subsurface waters. Here, we present a set of analytical solutions to predict the mean hyporheic downwelling fluxes and the hyporheic residence time distribution induced by the interaction between stream flow and two important bedforms: dune‐like and pool‐riffle. We also introduce two dimensionless numbers to characterize the hyporheic zone redox and thermal conditions at the bedform scale. These numbers are easy to quantify because they are derived by commonly measured reach‐scale hydromorphological stream data, which include hydraulic depth, mean flow velocity, mean streambed slope and streambed grain size distribution.
Gravel-Bed Rivers: Processes and Disasters
Oxford, UK
John Wiley & Sons Ltd.
978-1-118-97140-6
Tonina, D.; Marzadri, A.; Bellin, A.
Modeling Surface-Subsurface Exchange of Heat and Nutrients / Tonina, D.; Marzadri, A.; Bellin, A.. - ELETTRONICO. - (2017), pp. 235-260. [10.1002/9781118971437.ch9]
File in questo prodotto:
File Dimensione Formato  
ch9_GBR2017_Tonina_Marzadri_Bellin.pdf

Solo gestori archivio

Descrizione: Articolo principale
Tipologia: Versione editoriale (Publisher’s layout)
Licenza: Tutti i diritti riservati (All rights reserved)
Dimensione 1.42 MB
Formato Adobe PDF
1.42 MB Adobe PDF   Visualizza/Apri

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11572/176534
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 0
  • ???jsp.display-item.citation.isi??? ND
social impact