Papers by Marie-Audray Ouellet
i Population growth, poverty and agricultural intensification are putting pressures on Central Am... more i Population growth, poverty and agricultural intensification are putting pressures on Central American forests. In Panama, an increase in the area used for subsistence agriculture has been correlated to a continued decline in forest cover. Increasing deforestation is impacting rural peasants who find themselves in a subsistence crisis perpetuated by unsustainable agricultural practices such as slash and burn. As part of the ENVR 451 internship course, we investigated the link between poverty alleviation and conservation of the natural environment in order to provide our
i ABSTRACT Population growth, poverty and agricultural intensification are putting pressures on C... more i ABSTRACT Population growth, poverty and agricultural intensification are putting pressures on Central American forests. In Panama, an increase in the area used for subsistence agriculture has been correlated to a continued decline in forest cover. Increasing deforestation is impacting rural peasants who find themselves in a subsistence crisis perpetuated by unsustainable agricultural practices such as slash and burn. As part of the ENVR 451 internship course, we investigated the link between poverty alleviation and conservation of the natural environment in order to provide our host institution, CREA (Conservation through Research, Education and Action), with recommendations for the community outreach and farmers training programs they are planning on conducting in the community of La Zahina, Panama. In Panama, 52% of the poor are rural and women disproportionately represented in this group. The literature on rural poverty, development theories and income diversification strategie...
Ce rapport est le résultat de trois années de travail de caractérisation des eaux souterraines de... more Ce rapport est le résultat de trois années de travail de caractérisation des eaux souterraines de la Zone de gestion intégrée de l'eau Vaudreuil-Soulanges. Les auteurs désirent remercier toutes les personnes qui ont participé de près ou de loin à la réalisation du projet, les collaborateurs scientifiques, les étudiants de maîtrise et de doctorat, les stagiaires ainsi que le personnel de soutien de l'UQAM. Les travaux de terrain n'auraient pas pu avoir lieu sans la collaboration des habitants de la région, de la MRC, des municipalités et des ministères.
Les changements climatiques anticipes produiront des crues plus frequentes et des etiages plus pr... more Les changements climatiques anticipes produiront des crues plus frequentes et des etiages plus prononces qui menaceront la securite publique et l’etat des ecosystemes fluviaux. L’espace de liberte des cours d’eau est un cadre de gestion integree considerant l’hydrogeomorphologie des rivieres. Il vise a identifier des espaces d’inondabilite et de mobilite du cours d’eau ou on accepte de le laisser evoluer plutot que de le contraindre dans un trace faconne par les interventions anthropiques. Cette approche apparait prometteuse pour une gestion durable dans un climat changeant, car elle maintient les fonctions physiques naturelles des cours d’eau (transport de l’eau et des sediments), ce qui augmente leur resilience. L’espace de liberte reconnait aussi le role majeur de la connectivite entre la riviere et la nappe phreatique, notamment par l'entremise des milieux humides qui contribuent a l’attenuation des crues et des etiages et a une amelioration de la qualite de l’eau. Les objec...
Le Projet de connaissance des eaux souterraines de la zone de Vaudreuil-Soulanges finance dans le... more Le Projet de connaissance des eaux souterraines de la zone de Vaudreuil-Soulanges finance dans le cadre du Programme d'acquisition de connaissance des eaux souterraines(PACES) du ministere du Developpement durable, de l’Environnement et de la Lutte contre les Changements Climatiques (MDDELCC) avait pour but d’etablir la cartographie hydrogeologique de la Zone de gestion integree de l'eau de Vaudreuil-Soulanges dans la region de la Monteregie (superficie totale 814 km2). Ce projet a ete realise par l’Universite du Quebec a Montreal qui a mis en place une equipe formee de professeurs, d'agents de recherche, d'etudiants de doctorat, de maitrise et de stagiaires de premier cycle. Le projet a ete mene en collaboration avec les partenaires regionaux suivants : la MRC de Vaudreuil-Soulanges, l’organisme de bassin versant COBAVER-VS et l’Agence de geomatique monteregienne (GeoMont). Le Projet a ete realise au sein du Reseau quebecois sur les eaux souterraines (RQES). Ce proj...
Les ecosystemes sont naturellement adaptes pour faire face aux aleas du climat mais cette capacit... more Les ecosystemes sont naturellement adaptes pour faire face aux aleas du climat mais cette capacite est menacee par la rapidite des changements climatiques actuels. Les changements climatiques observes et anticipes sont consideres comme une grave menace a la biodiversite. Deja connues comme ayant un statut precaire, les especes vulnerables ou menacees sont d’autant plus sensibles a des modifications de leur habitat. L'exemple de la salamandre sombre des montagnes (Desmognathus ochrophaeus) au mont Covey Hill est typique de cette problematique. L'habitat de cette salamandre est intimement lie aux resurgences d’eau souterraine dont la dynamique hydrologique est controlee indirectement par le climat, par l’entremise de la recharge en eau souterraine. Toutefois, le controle qu'exercent les variables hydrologiques sur le maintien de cette population de salamandres est a peu pres inconnu. Ces connaissances sont necessaires pour definir des strategies d'adaptation aux change...
La peninsule gaspesienne est composee de petits bassins versants dont la dynamique fluviale est t... more La peninsule gaspesienne est composee de petits bassins versants dont la dynamique fluviale est tres sensible aux changements climatiques et environnementaux. Dans la perspective des changements climatiques en cours et anticipes, la variabilite des regimes d'ecoulement, notamment ceux a charge sedimentaire lies aux cones de dejection, devient moins previsible et peut constituer un risque pour la securite publique, risque exacerbe par l'emplacement de ces cones a l'interface versant-vallee. La presente etude constitue une analyse dendrogeomorphologique d'un petit cone de dejection en milieu forestier dans le but d'en caracteriser la dynamique en termes de frequence et d'intensite. Une demarche retrospective faisant appel a la dimension historique des evenements de forte intensite est privilegiee. La stratigraphie et la sedimentologie des depots etudies indiquent que le developpement du cone est associe a l'occurrence d'ecoulements hyperconcentres, proc...
Energy & Environmental Science
Hybrid modeling provides a unique opportunity to study cross-scale relationships in environmental... more Hybrid modeling provides a unique opportunity to study cross-scale relationships in environmental systems by linking together models of global, regional, landscape, and local-scale processes, yet the approach is rarely applied to address conservation and management questions. Here, we demonstrate how a hybrid modeling approach can be used to assess the effect of cross-scale interactions on the survival of the Allegheny Mountain Dusky Salamander (Desmognathus ochrophaeus) in response to changes in temperature and water availability induced by climate change at the northern limits of its distribution. To do so, we combine regional climate modeling with a landscape-scale integrated surface-groundwater flow model and an individual-based model of stream salamanders. On average, climate scenarios depict a warmer and wetter environment for the 2050 horizon. The increase in average annual temperature and extended hydrological activity time series in the future, combined with a better synchronization with the salamanders' reproduction period, result in a significant increase in the long-term population viability of the salamanders. This indicates that climate change may not necessarily limit the survivability of small, stream-dwelling animals in headwater basins located in cold and humid regions. This new knowledge suggests that habitat conservation initiatives for amphibians with large latitudinal distributions in Eastern North America should be prioritized at the northern limits of their ranges to facilitate species migration and persistence in the face of climate change. This example demonstrates how hybrid models can serve as powerful tools for informing management and conservation decisions.
Canadian Water Resources Journal / Revue canadienne des ressources hydriques, 2015
In the context of climate change, it is important to understand possible future projections and h... more In the context of climate change, it is important to understand possible future projections and historical trends of groundwater recharge, flow, and discharge to surface reservoirs. Knowledge of a vast range of possible conditions is required to fully appreciate the variability of the hydrologic cycle and hence the long-term vulnerability of groundwater-dependent habitats. This research investigates historical trends for a groundwater–surface water interacting system that supports a fragile ecosystem in southern Quebec. A transient model was developed using MODFLOW to simulate site-wide groundwater flow for the study area. The model was used to simulate past hydrogeological conditions (1900–2010) using a new data set of available precipitation (rain and snowmelt) and temperature. This data set was used to simulate the overall groundwater budget and to determine groundwater discharge (river baseflow and spring flow) in the study area. This allows for the quantification of century-long trends in flow data, as well as the extreme maximum and minimum flows over 110 years. Recharge was variable, ranging from 41 to 197 mm/year over the study period. Lower recharge rates from 1950 to 1965 induced marked effects on spring flow. Although the trend is not statistically significant, there appears to be, for the second half of the study period (1966–2010), a tendency towards a reversal to an increase for recharge, hydraulic heads, spring flow and baseflows. A longer time series would be necessary to confirm this tendency. The simulated historical trends are compared with flow projections for future scenarios (2041–2070). The confirmation that the natural system has been subjected to a wide range of climatic conditions over the last century helps to inform about its resilience. This study highlights the utility of groundwater flow modeling using historical climate data sets to gain a better understanding of long-term trends for climate change-related hydrogeological and ecohydrological studies.
Geomorphology, 2015
Abstract The freedom space concept applies hydrogeomorphic principles to delineate zones that are... more Abstract The freedom space concept applies hydrogeomorphic principles to delineate zones that are either frequently flooded or actively eroding, or that include riparian wetlands. Freedom space limits mapped for three rivers in southern Quebec (Canada) were assessed to determine whether they would still be valid under a future climate using a sensitivity analysis approach with numerical models predicting mobility of meanders (RVRMeander) and flood stage (HEC-RAS). The freedom space limits were also used in a cost–benefit analysis over a 50-year period where costs consist of loss or limitations to the right of farming and construction in this zone, whereas benefits are avoided costs for existing or future bank stabilization structures and avoided costs of flooding in agricultural areas. The economic value of ecosystem services provided by riparian wetlands and increased buffer zones within the freedom space were also included in the analysis. Results show that freedom space limits would be robust in future climate, and show net present values ranging from CDN$0.7 to $3.7 million for the three rivers, with ratios of benefits over costs ranging between 1.5:1 and 4.8:1. River management based on freedom space is thus beneficial for society over a 50-year period.
Progress in Physical Geography: Earth and Environment, 2013
Subaerial sediment-water flows on hillslopes have received growing attention from the scientific ... more Subaerial sediment-water flows on hillslopes have received growing attention from the scientific community in recent years. Interest in this type of geomorphic process is twofold: they constitute a major risk factor and they have generally been poorly defined in the past. Major classification schemes are considered here, with a particular interest in criteria for discriminating between various subaerial flow type processes. Identification techniques from various fields (morphometry, rheology, geomorphology, sedimentology) are reviewed. Recent accounts of flow processes as part of a continuum of processes as opposed to belonging to distinct categories are discussed. It is proposed that process identification include information drawn from various methods in order to minimize identification error, given that correct identification is essential to appropriate hazard assessment and mitigation measures.
Journal of Hydrology, 2014
Groundwater discharge areas, including low-flow bedrock aquifer springs, are ecologically importa... more Groundwater discharge areas, including low-flow bedrock aquifer springs, are ecologically important and can be impacted by climate change. The development of and results from a groundwater modeling study simulating fractured bedrock spring flow are presented. This was conducted to produce hydrological data for an ecohydrological study of an endangered species, Allegheny Mountain Dusky Salamanders (Desmognathus ochrophaeus), in southern Quebec, Canada. The groundwater modeling approach in terms of scale and complexity was strongly driven by the need to produce hydrological data for the related ecohydrological modeling. Flows at four springs at different elevations were simulated for recent past conditions (2006-2010) and for reference (1971-2000) and future (2041-2070) periods using precipitation and temperature data from ten climate scenarios. Statistical analyses of spring flow parameters including activity periods and duration of flow were conducted. Flow rates for the four simulated springs, located at different elevations, are predicted to increase between 2% and 46% and will be active (flowing) 1% to 2% longer in the future. A significant change (predominantly an increase) looking at the seasonality of the number of active days occurs in the winter (2% to 4.9%) and spring seasons (-0.6% to 6.5%). Greatest flow rates were produced from springs at elevations where sub-horizontal fractures intersect the ground surface. These results suggest an intensification of the spring activity at the study site in context of climate change by 2050, which provides a positive habitat outlook for the endangered salamanders residing in the springs for the future.
Hydrological Processes, 2013
Interactions between headwater aquifers and peatlands have received limited scientific attention.... more Interactions between headwater aquifers and peatlands have received limited scientific attention. 26 Hydrological stresses, including those related to climate change, may adversely impact these 27 interactions. In this study, the dynamics of a southern Quebec headwater system where a peatland 28 is present is simulated under current conditions and with climate change. The model is calibrated 29 in steady-state on field-measured data and provides satisfactory results for transient state 30 conditions. Under current conditions, simulations confirm that the peatland is fed by the fractured 31 bedrock aquifer year round and provides continuous baseflow to its outlets. Climate change is 32 simulated through its impact on groundwater recharge. Predicted precipitation and temperature 33 data from a suite of Regional Climate Model scenarios provide a net precipitation variation range 34 from +10% to-30% for the 2041-2070 horizon. Calibrated recharge is modified within this range 35 to perform a sensitivity analysis of the headwater model to recharge variations (+10%,-15% and 36-30%). Total contribution from the aquifer to rivers and streams varies from +14% to-44% of the 37 baseline for +10% to-30% recharge changes from spring 2010 data, for example. With higher 38 recharge, the peatland receives more groundwater, which could significantly change its 39 vegetation pattern and eventually ecosystem functions. For-30% recharge, the peatland becomes 40 perched above the aquifer during the summer, fall and winter. Recharge reductions also induce 41 sharp declines in groundwater levels and drying streams.
Earth Surface Processes and Landforms, 2014
The assessment of the dominant flow type on alluvial fans usually refers to two categories: debri... more The assessment of the dominant flow type on alluvial fans usually refers to two categories: debris-flow fans (i.e. sediment gravity flows) and fluvial fans (i.e. fluid gravity flows). Here we report the results of combined morphometric, stratigraphic and sedimentological approaches which suggest that hyperconcentrated flows, a transitional process rheologically distinct from debris flows and floods and sometimes referred to as debris floods, mud floods, or transitional debris flows, are the dominant fan building process in eastern Canada. These flows produce transitional facies between those of debris flows which consist of a cohesive matrix-supported diamicton, and those of river flows which display more distinct stratification. The size of the blocks in the channels and the abrasion scars at the base of several trees attest to the high transport capacity of these flows. The fan channels are routed according to various obstacles comprised primarily of woody debris that impede sediment transit. However, these conditions of sediment storage are combined with readily available sediment due to the friable nature of the local lithology. Tree-ring analysis allowed the reconstruction of eight hydrogeomorphic events which are characterized by a return period of 9.25 years for the period 1934–2008, although most of the analyzed events occurred after 1970. Historical weather data analysis indicates that they were related to rare hydrometeorological events at regional and local scales. This evidence led to the elaboration of weather scenarios likely responsible for triggering flows on the fan. According to these scenarios, two distinct hydrologic regimes emerge: the torrential rainfall regime and the nival regime related to snowmelt processes. Hydrogeomorphic processes occurring in a cold-temperate climate, and particularly on small forested alluvial fans of north-eastern North America, should receive more attention from land managers given the hazard they represent, as well as because of their sensitivity to various meteorological parameters. Copyright © 2014 John Wiley & Sons, Ltd.
Environmental Management, 2014
River systems are increasingly under stress and pressure from agriculture and urbanization in rip... more River systems are increasingly under stress and pressure from agriculture and urbanization in riparian zones, resulting in frequent engineering interventions such as bank stabilization or flood protection. This study provides guidelines for a more sustainable approach to river management based on hydrogeomorphology concepts applied to three contrasted rivers in Quebec (Canada). Mobility and flooding spaces are determined for the three rivers, and three levels of ''freedom space'' are subsequently defined based on the combination of the two spaces. The first level of freedom space includes very frequently flooded and highly mobile zones over the next 50 years, as well as riparian wetlands. It provides the minimum space for both fluvial and ecological functionality of the river system. On average for the three studied sites, this minimum space was approximately 1.7 times the channel width, but this minimum space corresponds to a highly variable width which must be determined from a thorough hydrogeomorphic assessment and cannot be predicted using a representative average. The second level includes space for floods of larger magnitude and provides for meanders to migrate freely over a longer time period. The last level of freedom space represents exceptional flood zones. We propose the freedom space concept to be implemented in current river management legislation because it promotes a sustainable way to manage river systems, and it increases their resilience to climate and land use changes in comparison with traditional river management approaches which are based on frequent and spatially restricted interventions.
Hydrological Processes, 2014
In areas where peatlands are abundant, they are likely to play a significant role in the hydrolog... more In areas where peatlands are abundant, they are likely to play a significant role in the hydrological and hydrogeological dynamics of a watershed. Although individual case studies are reported in the literature, there is a large range of aquifer-peatland interactions and there is a need to understand the controls of these interactions. The objectives of this study were (1) to better understand aquifer-peatland connections and how these may be predicted by geology and geomorphic location and to provide a variety of reference sites for glacial geological settings. Slope and depression peatlands were studied in the Abitibi-Témiscamingue region and in the St. Lawrence Lowlands, two contrasting regions of southern Quebec. A total of 12 transects that span a shallow aquifer-peatland interface were instrumented with piezometers. Field investigations included peatland characterization, monthly water level monitoring, and continuous hydraulic head measurements with pressure transducers. The results indicate that 7 of the 12 transects receive groundwater from the surrounding shallow aquifer. At the peatland margin, four lateral flow patterns were identified and associated with slope peatlands (parallel inflow and divergent flow) and with depression peatlands (convergent flow and parallel outflow). Vertical hydraulic gradients suggest that water flows mainly downwards, i.e. from the peatland to the underlying mineral deposits. Vertical connectivity appears to decrease as the distance from the peatland margin increases. All of these exchanges are important components in the sustainability of peatland hydrogeological functions. The regional comparison of aquifer-peatland flow dynamics performed in this study provides a new set of referenced data for the assessment of aquifer-peatland connectivity.
Environmental Management, 2014
River systems are increasingly under stress and pressure from agriculture and urbanization in rip... more River systems are increasingly under stress and pressure from agriculture and urbanization in riparian zones, resulting in frequent engineering interventions such as bank stabilization or flood protection. This study provides guidelines for a more sustainable approach to river management based on hydrogeomorphology concepts applied to three contrasted rivers in Quebec (Canada). Mobility and flooding spaces are determined for the three rivers, and three levels of ''freedom space'' are subsequently defined based on the combination of the two spaces. The first level of freedom space includes very frequently flooded and highly mobile zones over the next 50 years, as well as riparian wetlands. It provides the minimum space for both fluvial and ecological functionality of the river system. On average for the three studied sites, this minimum space was approximately 1.7 times the channel width, but this minimum space corresponds to a highly variable width which must be determined from a thorough hydrogeomorphic assessment and cannot be predicted using a representative average. The second level includes space for floods of larger magnitude and provides for meanders to migrate freely over a longer time period. The last level of freedom space represents exceptional flood zones. We propose the freedom space concept to be implemented in current river management legislation because it promotes a sustainable way to manage river systems, and it increases their resilience to climate and land use changes in comparison with traditional river management approaches which are based on frequent and spatially restricted interventions.
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Papers by Marie-Audray Ouellet