Shopping for hydrologically representative connectivity metrics in a humid temperate forested catchment

Ali, Genevieve; Roy, Alain

doi:10.1029/2010wr009442

Cited by 94 publications

(113 citation statements)

References 60 publications

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“…1). It is worth noticing that a similar evolution occurred simultaneously in the neighboring fields of surface hydrology [13][14][15][16][17][18][19][20], geomorphology [21][22][23][24], landscape ecology [25][26][27][28], pore scale or soil physics [29][30][31][32][33][34].…”

Section: Introductionmentioning

confidence: 99%

“…The word connectivity is often used as a broad concept with various definitions related for example to the efficiency with which runoff moves from source areas to streams [35] or to the presence of an unsaturated zone between a river and an underlying aquifer [36]. Therefore, as pointed out by several authors [37,18,19], there is a need to adopt some standards and to share them.…”

Section: Introductionmentioning

confidence: 99%

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Connectivity metrics for subsurface flow and transport

Renard

Allard

2013

Advances in Water Resources

346

258

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a b s t r a c tUnderstanding the role of connectivity for the characterization of heterogeneous porous aquifers or reservoirs is a very active and new field of research. In that framework, connectivity metrics are becoming important tools to describe a reservoir. In this paper, we provide a review of the various metrics that were proposed so far, and we classify them in four main groups. We define first the static connectivity metrics which depend only on the connectivity structure of the parameter fields (hydraulic conductivity or geological facies). By contrast, dynamic connectivity metrics are related to physical processes such as flow or transport. The dynamic metrics depend on the problem configuration and on the specific physics that is considered. Most dynamic connectivity metrics are directly expressed as a function of an upscaled physical parameter describing the overall behavior of the media. Another important distinction is that connectivity metrics can either be global or localized. The global metrics are not related to a specific location while the localized metrics relate to one or several specific points in the field. Using these metrics to characterize a given aquifer requires the possibility to measure dynamic connectivity metrics in the field, to relate them with static connectivity metrics, and to constrain models with those information. Some tools are already available for these different steps and reviewed here, but they are not yet routinely integrated in practical applications. This is why new steps should be added in hydrogeological studies to infer the connectivity structure and to better constrain the models. These steps must include specific field methodologies, interpretation techniques, and modeling tools to provide more realistic and more reliable forecasts in a broad range of applications.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Connectivity metrics for subsurface flow and transport

Renard

Allard

2013

Advances in Water Resources

346

258

View full text Add to dashboard Cite

show abstract

“…Over the past decade there have been numerous attempts to characterise the connectivity/disonnectivity dynamic (Ali and Roy, 2010;Meerkerk et al, 2009;Michaelides and Chappell, 2009;Tetzlaff et al, 2007). Pringle (2003b) noted the variety of definitions of connectivity, used across and within disciplines.…”

Section: Introductionmentioning

confidence: 99%

A generalized Damköhler number for classifying material processing in hydrological systems

Oldham

Farrow

Peiffer

2013

Hydrol. Earth Syst. Sci.

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Abstract. Assessing the potential for transfer of pollutants and nutrients across catchments is of primary importance under changing land use and climate. Over the past decade the connectivity/disconnectivity dynamic of a catchment has been related to its potential to export material; however, we continue to use multiple definitions of connectivity, and most have focused strongly on physical (hydrological or hydraulic) connectivity. In contrast, this paper constantly focuses on the dynamic balance between transport and material transformation, and defines material connectivity as the effective transfer of material between elements of the hydrological cycle. The concept of exposure timescales is developed and used to define three distinct regimes: (i) which is hydrologically connected and transport is dominated by advection; (ii) which is hydrologically connected and transport is dominated by diffusion; and (iii) which is materially isolated. The ratio of exposure timescales to material processing timescales is presented as the non-dimensional number, N E , where N E is reaction-specific and allows estimation of relevant spatial scales over which the reactions of interest take place. Case studies within each regime provide examples of how N E can be used to characterise systems according to their sensitivity to shifts in hydrology and gain insight into the biogeochemical processes that are signficant under the specified conditions. Finally, we explore the implications of the N E framework for improved water management, and for our understanding of biodiversity, resilience and chemical competitiveness under specified conditions.

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“…number of days elapsed since the last rainfall intensity exceeding 30 mm/d) appeared to be the most influential surrogate measure for AMCs: the smaller the value of DSP 30 , the more likely the presence of 0.85-1.4 ha wide saturation patches at a depth of 15 cm. In a paper aiming to identify hydrologically representative connectivity metrics in the Hermine catchment, Ali and Roy (2010d) found that the spatial connectedness of locations whose volumetric soil moisture content exceeded 30% was rather dependent upon AP 7 (i.e. 7-day antecedent precipitation).…”

Section: Introductionmentioning

confidence: 99%

“…"××" means that a strong significant correlation was found, "×" means that rather weak correlations were found, and blanks mean that no significant correlations were found. Spatial connectivity of locations whose volumetric soil ×× moisture content exceeds 30% Source : Ali et al, 2010d Development of spatially coherent saturation patches on:…”

Section: Introductionmentioning

confidence: 99%

A case study on the use of appropriate surrogates for antecedent moisture conditions (AMCs)

Ali¹,

Roy²

2010

Hydrol. Earth Syst. Sci.

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Abstract.While a large number of non-linear hillslope and catchment rainfall-runoff responses have been attributed to the temporal variability in antecedent moisture conditions (AMCs), two problems emerge: (1) the difficulty of measuring AMCs, and (2) the absence of explicit guidelines for the choice of surrogates or proxies for AMCs. This paper aims at determining whether or not multiple surrogates for AMCs should be used in order not to bias our understanding of a system hydrological behaviour. We worked in a small forested catchment, the Hermine, where soil moisture has been measured at 121 different locations at four depths on 16 occasions. Without making any assumption on active processes, we used various linear and nonlinear regression models (i.e. linear, quadratic, cubic, exponential, logarithmic and logistic) to evaluate the point-scale temporal relations between actual soil moisture contents and selected meteorologicalbased surrogates for AMCs. We then mapped the nature of the "best fit" model to identify (1) spatial clusters of soil moisture monitoring sites whose hydrological behaviour was similar, and (2) potential topographic influences on these behaviours. Two conclusions stood out. Firstly, it was shown that the sole reference to AMCs indices traditionally used in catchment hydrology, namely antecedent rainfall amounts summed over periods of seven or ten days, would have led to an incomplete understanding of the Hermine catchment dynamics. Secondly, the relationships between point-scale soil moisture content and surrogates for AMCs were not spatially homogeneous, thus revealing a mosaic of linear and nonlinear catchment "active" and "contributing" sources whose locations were seldom controlled by surface terrain attributes or the topography of a soil-confining layer interface. These Correspondence to: G. A. Ali (genevieve.ali@umontreal.ca) results represent a step forward for the Hermine catchment as they point towards depth-specific processes and spatiallyvariable triggering conditions that are not controlled by topography. Further investigations are, however, necessary in order to derive general guidelines for the choice of the best surrogates for AMCs in a catchment.

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Shopping for hydrologically representative connectivity metrics in a humid temperate forested catchment

Cited by 94 publications

References 60 publications

Connectivity metrics for subsurface flow and transport

Connectivity metrics for subsurface flow and transport

A generalized Damköhler number for classifying material processing in hydrological systems

A case study on the use of appropriate surrogates for antecedent moisture conditions (AMCs)

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