Modelling two‐dimensional steady‐state groundwater flow and flow sensitivity to boundary conditions in blanket peat complexes

Lapen, David R.; Price, Jonathan S.; Gilbert, Robert G.

doi:10.1002/hyp.1507

Cited by 40 publications

(44 citation statements)

References 23 publications

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“…For example, Mitchell et al (2008) found the edges of some peatlands to be important in regulating the production of methyl mercury due to the transport of solutes in upland runoff to the peatland perimeter. As an alternative example, we would still be able to identify a near-surface zone of high hydraulic conductivity (Ingram, 1978), but also a central zone of low mineral content (Mitchell et al, 2008) or a marginal zone of low hydraulic conductivity (Lapen et al, 2005;Baird et al, 2008).…”

Section: Hot Spots and Cold Spotsmentioning

confidence: 96%

“…Complexity: The long-term development of peatland ecosystems and soils, as well as their short-to mediumterm responses to disturbance, is governed by a complex web of interacting hydrological, ecological and biogeochemical feedbacks across a range of spatial and temporal scales (Vitt et al, 2000;Belyea and Baird, 2006;Yu, 2006;Ise et al, 2008;Belyea, 2009). Recent research indicates that horizontal spatial heterogeneity in peat properties, structures and process rates plays a key role in regulating various aspects of peatland system behaviour (Lapen et al, 2005;Baird et al, 2008;Eppinga et al, 2009a). Models that neglect some of these feedbacks or the role of spatial heterogeneity risk misrepresenting system-scale behaviour (Belyea, 2009;Eppinga et al, 2009a).…”

Section: Design Criteria For a Conceptual Framework In Peatland Ecohymentioning

confidence: 99%

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Conceptual frameworks in peatland ecohydrology: looking beyond the two‐layered (acrotelm–catotelm) model

et al. 2011

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Northern peatlands are important shallow freshwater aquifers and globally significant terrestrial carbon stores. Peatlands are complex, ecohydrological systems, commonly conceptualized as consisting of two layers, the acrotelm (upper layer) and the catotelm (lower layer). This diplotelmic model, originally posited as a hypothesis, is yet to be tested in a comprehensive manner. Despite this, the diplotelmic model is highly prevalent in the peatland literature, suggesting a general acceptance of the concept. We examine the diplotelmic model with respect to what we believe are three important research criteria: complexity, generality and flexibility. The diplotelmic model assumes that all ecological, hydrological and biogeochemical processes and structures can be explained by a single discrete boundary-depth in relation to a drought water table. This assumption makes the diplotelmic scheme inherently inflexible, in turn hindering its representation of a range of ecohydrological phenomena. We explore various alternative conceptual approaches that might offer greater flexibility, including the representation of horizontal spatial heterogeneity and transfers. We propose that the concept of hot spots, prevalent in terrestrial biogeochemistry literature, might be extended to peatland ecohydrology, providing a more flexible conceptual framework. Hot spots are areas of a peatland which exhibit fast processing rates in a number of mechanistically linked hydrological, ecological and biogeochemical processes. The complementary concept of cold spots may also be useful in peatland ecohydrology, particularly with regards to understanding the vulnerability of peatlands to disturbance. The flexibility of our suggested scheme may allow the future incorporation of ecohydrological phenomena yet to be identified as important in peatlands.

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Section: Hot Spots and Cold Spotsmentioning

confidence: 96%

Section: Design Criteria For a Conceptual Framework In Peatland Ecohymentioning

confidence: 99%

Conceptual frameworks in peatland ecohydrology: looking beyond the two‐layered (acrotelm–catotelm) model

et al. 2011

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“…However, when the higher values of K from each bog's interior were applied to its margins, the modelled water tables were substantially lower (15-30 cm) than that in the calibrated model. On the basis of these findings, Lapen et al (2005) concluded that a zone of lower K at each bog's margin was fundamental to maintaining wet conditions in the bog interior and also important in the development (growth) of bog domes because peat will generally accumulate 291 more readily where conditions are wet close to the ground surface (cf. Belyea and Baird, 2006).…”

Section: Hypothesismentioning

confidence: 96%

The hydraulic structure of a raised bog and its implications for ecohydrological modelling of bog development

Baird

Eades²,

Surridge

2008

Ecohydrology

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Raised bogs are important ecohydrological systems in which there are strong two-way links between plant succession, litter and peat decay, and hydrological functioning. Using recently established protocols, we measured the hydraulic structure of a raised bog in West Wales. We tested two hypotheses: (i) that the hydraulic conductivity (K) of the peat shows depth dependency such that lower layers of peat are effectively impermeable, and (ii) that the K of the marginal peat of the bog dome is lower than that in central areas. From 107 piezometer measurements we found there was depth dependency of K but that lower peat layers were not poorly permeable or impermeable. We also found that the K of the peat on the margin of the bog dome was generally significantly lower than that in central areas. Our results suggest that, for some bogs at least, it is important to simulate water flow through deeper peats when simulating peatland development or growth. They also raise the intriguing possibility that the low K of marginal peat is important in maintaining wet conditions in central bog areas, allowing bogs to reach greater thicknesses than they would do in the absence of the low-K margin; an idea first proposed for blanket bogs by Lapen et al. (2005).

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“…Hydrogeological setting controls the groundwater regime and development of peatlands in the Hudson Bay Lowlands (Glaser et al, 2004); in maritime blanket bogs (Lapen et al, 2005); in hyper-maritime forested peatlands and in a kettle-hole wetland (Dempster et al, 2006). Changes to groundwater regimes have been noted in response to wet/dry cycles and humaninduced disturbances.…”

Section: Groundwater and Peat Propertiesmentioning

confidence: 99%

“…Lapen et al (2005) used a model of blanket peatlands to show that lower hydraulic conductivity of lagg peats redistribute water to the surface.…”

Section: Groundwater and Peat Propertiesmentioning

confidence: 99%

Advances in Canadian Peatland Hydrology, 2003-2007

Waddington¹,

Quinton²,

Price³

et al. 2009

Canadian Water Resources Journal

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Abstract:Peatlands represent over 90% of Canadian wetlands and are the focus of considerable hydrological and biogeochemical research. Research on evapotranspiration (ET) has shown that it can exceed annual precipitation (P) where there are replenishing flood events. Evaporation from open water ponds in boreal peatlands exceeds ET from vegetated riparian zones by about two times, but surrounding forests can shelter small ponds by reducing turbulence. In an open bog, evaporation was modelled by separating the surface into vascular vegetation, hummock moss and hollow moss surfaces, and showed that vascular plants contribute 60-80% of ET, mosses making up the remainder with hummock mosses dominant over hollows. Runoff from peatlands is enhanced by features ranging from headwater swamps, ice-cored peat plateaus, patchy arctic wetlands and even sections of riverine peatlands. Groundwater fluxes can be quite erratic, and depend on transient properties of the peat that depend on moisture content (e.g., unsaturated hydraulic conductivity) to unsteady saturated hydraulic properties (e.g., hydraulic conductivity, specific yield) caused by peat compression and dilation associated with water storage changes. Surface elevation adjustments can result in a more stable depth to water table, increase evaporation losses, increase methane emission, and attenuate pore-water concentration of contaminants. Research on Canadian peatlands has also made significant methodological advances, including measurement of hydraulic properties of living mosses and peat pore-water and pore dimension characteristics. A considerable multi-annual effort has also been made in evaluating carbon dynamics from Canadian peatlands. Summer moisture availability is important to determining carbon fluxes with some peatlands experiencing enhanced productivity following drought (water table drawdown). Sudden changes in water table elevation promote DOC production and export. Methane bubbles confound hydraulic gradients and flows by creating local pockets of pressure, which are then released episodically when the entrapped gas reaches a threshold content. Canadian peatland hydrology continues to be actively researched in lab, field and modelling studies.

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Modelling two‐dimensional steady‐state groundwater flow and flow sensitivity to boundary conditions in blanket peat complexes

Cited by 40 publications

References 23 publications

Conceptual frameworks in peatland ecohydrology: looking beyond the two‐layered (acrotelm–catotelm) model

Conceptual frameworks in peatland ecohydrology: looking beyond the two‐layered (acrotelm–catotelm) model

The hydraulic structure of a raised bog and its implications for ecohydrological modelling of bog development

Advances in Canadian Peatland Hydrology, 2003-2007

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