University of Oulu

Autio, A., Ala‐Aho, P., Ronkanen, A.‐K., Rossi, P. M., Kløve, B. (2020). Implications of peat soil conceptualization for groundwater exfiltration in numerical modeling: A study on a hypothetical peatland hillslope. Water Resources Research, 56, e2019WR026203. https://doi.org/10.1029/2019WR026203

Implications of peat soil conceptualization for groundwater exfiltration in numerical modeling : a study on a hypothetical peatland hillslope

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Author: Autio, Anna1; Ala‐Aho, Pertti1; Ronkanen, Anna‐Kaisa1;
Organizations: 1Water, Energy and Environmental Engineering Research Unit, University of Oulu, Oulu, Finland
Format: article
Version: accepted version
Access: open
Online Access: PDF Full Text (PDF, 1.8 MB)
Persistent link: http://urn.fi/urn:nbn:fi-fe20201214100585
Language: English
Published: American Geophysical Union, 2020
Publish Date: 2020-12-14
Description:

Abstract

Fully integrated physically based hydrological modeling is an essential method for increasing hydrological understanding of groundwater‐surface water (GW‐SW) interactions in peatlands and for predicting anthropogenic impacts on these unique ecosystems. Modeling studies represent peat soil in a simplistic manner, as a homogeneous layer of uniform thickness, but field measurements consistently show pronounced spatial variability in peatlands. This study evaluated uncertainty in groundwater levels and exfiltration fluxes associated with the simplified representation of the peat soil layer. For transferability of the results, impacts of selected topographical and hydrogeological conceptual models on GW‐SW exchange fluxes were simulated in a hypothetical hillslope representing a typical aquifer‐mire transect. The results showed that peat soil layer geometry defined the simulated spatial GW‐SW exchange patterns and groundwater flow paths, whereas total groundwater exfiltration flux to the hillslope and groundwater level in the peatland were only subtly altered by different conceptual peat soil geometry models. GW‐SW interactions were further explored using different scenarios and dimensionless parameters for peat hydraulic conductivity and hillslope‐peatland system slope. The results indicated that accurate representation of physical peat soil properties and landscape topography is important when the main objective is to model spatial GW‐SW exchange. Groundwater level in virtual peatland was not greatly affected by groundwater drawdown in an adjacent aquifer, but the magnitude and spatial distribution of GW‐SW interactions was significantly altered. This means that commonly used groundwater depth observations near peat‐mineral soil interfaces and within peatlands may not be a suitable indicator for monitoring the hydrological state of groundwater‐dependent peatland ecosystems.

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Series: Water resources research
ISSN: 0043-1397
ISSN-E: 1944-7973
ISSN-L: 0043-1397
Volume: 56
Issue: 8
Article number: e2019WR026203
DOI: 10.1029/2019WR026203
OADOI: https://oadoi.org/10.1029/2019WR026203
Type of Publication: A1 Journal article – refereed
Field of Science: 218 Environmental engineering
Subjects:
Funding: The first author was funded by the Aurora Doctoral Programme in Environment, Society and Technology in the North (Aurora‐DP) of the University of Oulu and by personal grants received from the foundations: Maa‐ ja vesitekniikan tuki ry, Oulun läänin talousseuran maataloussäätiö, and Tauno Tönningin Säätiö.
Copyright information: © 2020. American Geophysical Union. All Rights Reserved. An edited version of this paper was published by AGU.