During the 2017 and 2019 spring freshets, exceptional peak flows affected a number of regions of southern Quebec, resulting in property damage of hundreds of millions of dollars. The analysis in this article aims to document the large-scale hydrometeorological conditions associated with these floods over the southern part of the province. The main results show that record-breaking flows were reported during the spring freshets in 17% of the studied catchments during these two years. Eight percent of the catchments reported flows higher than ever before in 2017, and three of these catchments broke their records again in 2019. These floods were primarily caused by intense rainfall events which surpassed the 95th percentile by more than 150%. These rainfall events accelerated snowmelt, with quantities more than 200% of the 95th percentile, contributing exceptional, and sometimes extreme, inputs of water throughout the province. Higher peak flows occurred in catchments with smaller surface areas and high flashiness. On the other hand, regulated catchments had relatively low peak flows.
Analyzing the impacts of climate change on precipitation patterns, encompassing daily, seasonal, and extreme values, at the catchment scale is critical for understanding regional hydrological changes and informing water resource management strategies. This study examines projected changes in precipitation patterns across eleven major Canadian catchments under various Shared Socioeconomic Pathways (SSPs) using 9-km downscaled CMIP6 simulations. By analyzing daily, seasonal, and extreme precipitation metrics, we provide insights into future precipitation dynamics. Results show significant increases in daily precipitation magnitudes, with northern and coastal regions experiencing the highest growth rates, particularly under SSP5-8.5. Seasonal analysis highlights pronounced precipitation growth during spring and winter, with coastal and mountainous regions exhibiting consistently high values. Extreme precipitation events, including annual maxima and the 95th and 99th percentiles, intensify under high-emission scenarios, with northern regions experiencing the largest relative increases. These findings underscore the critical need for region-specific climate adaptation strategies to mitigate risks related to flooding, water resource management, and infrastructure resilience in a changing climate. L'analyse des impacts du changement climatique sur les r & eacute;gimes de pr & eacute;cipitations, incluant les valeurs journali & egrave;res, saisonni & egrave;res et extr & ecirc;mes, & agrave; l'& eacute;chelle du bassin versant est essentielle pour comprendre les & eacute;volutions hydrologiques r & eacute;gionales et orienter les strat & eacute;gies de gestion des ressources en eau. Cette & eacute;tude examine les changements projet & eacute;s des r & eacute;gimes de pr & eacute;cipitations dans onze grands bassins versants canadiens selon diff & eacute;rents sc & eacute;narios socio & eacute;conomiques partag & eacute;s (Shared Socioeconomic Pathways, SSP), & agrave; partir de simulations CMIP6 d & eacute;sagr & eacute;g & eacute;es spatialement & agrave; une r & eacute;solution de 9 km. L'analyse des indicateurs journaliers, saisonniers et extr & ecirc;mes met en & eacute;vidence une augmentation significative des intensit & eacute;s journali & egrave;res, les r & eacute;gions nordiques et c & ocirc;ti & egrave;res enregistrant les taux de croissance les plus & eacute;lev & eacute;s, particuli & egrave;rement sous le sc & eacute;nario SSP5-8.5. & Agrave; l'& eacute;chelle saisonni & egrave;re, les pr & eacute;cipitations augmentent de mani & egrave;re marqu & eacute;e au printemps et en hiver, avec des valeurs syst & eacute;matiquement & eacute;lev & eacute;es dans les r & eacute;gions c & ocirc;ti & egrave;res et montagneuses. Les & eacute;v & eacute;nements de pr & eacute;cipitations extr & ecirc;mes, incluant les maxima annuels ainsi que les percentiles 95e et 99e, s'intensifient sous les sc & eacute;narios & agrave; fortes & eacute;missions, les r & eacute;gions nordiques pr & eacute;sentant les hausses relatives les plus importantes. Ces r & eacute;sultats soulignent la n & eacute;cessit & eacute; de mettre en oeuvre des strat & eacute;gies d'adaptation climatique adapt & eacute;es aux sp & eacute;cificit & eacute;s r & eacute;gionales afin d'att & eacute;nuer les risques li & eacute;s aux inondations, & agrave; la gestion des ressources hydriques et & agrave; la r & eacute;silience des infrastructures dans un contexte de changement climatique.
This study quantifies the spatiotemporal variability of snow water equivalent (SWE) using a set of complementary statistical approaches across site, grid, and sub-basin scales. It incorporates in-situ measurements, remote sensing, reanalysis, and machine learning-derived datasets for the period 2000-2020 across the Mackenzie River Basin (MRB). Employing a comprehensive evaluation framework, we assessed the performance of multiple gridded SWE datasets against area-averaged in-situ observations at both lowland and highland sites over time, and ERA5-Land reanalysis. Spatiotemporally, the gridded SWE datasets reproduce well-observed seasonal and interannual cycles and the patterns of spatial variability; however, the random forest (RF) model demonstrates superior accuracy and reliability, achieving the highest correlations (R-2 = 0.72 and R-2 = 0.95) and the lowest errors (RMSE = 43.1 and 37.2 mm) when compared to the lowland and highland in-situ measurements, respectively. Annual and seasonal SWE variations were prominent, with peak values exceeding 700 mm in highland regions during late winter and early spring, reflecting the region's climatic conditions. The RF feature importance and principal component analysis indicate that snow-related parameters, including snow depth, density and snowfall are the primary drivers of SWE estimates in MRB. Our results reveal a slight, though statistically insignificant, decreasing trend in SWE (for example, a Sen's slope of -0.301 mm/year with a p-value of 0.26 in highland in-situ sites), which could suggest potential impacts of climate change on snow accumulation. These findings underscore the critical role of SWE in the basin's hydrological processes and future water resources. The insights provided could further enhance our understanding of SWE spatiotemporal variations, providing a basis for improved inputs in the future numerical hydrologic modeling within the Mackenzie River basin.
Mountain protected areas are highly vulnerable to land use changes and tourism pressures, which can present as degraded water quality from urban stormwater contamination. Using a standardized framework, we conducted a screening-level ecological risk assessment (SLERA) of stormwater quality in the main townsite of Banff National Park, Alberta, Canada. The town of Banff is home to approximately 8,300 residents but experiences large-scale anthropogenic pressure from more than four million annual visitors. End-of-pipe grab samples were collected from four outfalls and two upstream sites representing background conditions, during 21 rainfall and snowmelt events. Samples were assessed using a water quality index (WQI), which rated stormwater effluent from three outfalls as 'poor' and one outfall as 'marginal', while background sites rated 'good' and 'excellent'. The outfalls exhibited similar contaminant profiles, with frequent WQI exceedances for cadmium, copper, lead, zinc, total phosphorous, total suspended solids and turbidity. Chloride exceedances were observed exclusively in snowmelt and approached concentrations typical of large municipalities. Embedding a WQI within a SLERA framework provides a novel and transferable approach for preliminary risk identification where data and monitoring capacity are limited, particularly in small, cold climate municipalities.
Lake Scugog is a large headwater reservoir located in southern Ontario that serves as a major drinking water source across its watershed and beyond. Due to its role as a sizable feeder system to the nationally significant Trent-Severn Waterway (TSW), and status as a provincially significant inland fishery, a watershed-scale water-quality-monitoring program was established in 2004. We assessed 20 years of the irregular time-series with general additive models to identify significant periods of change in water quality parameters, as well as finite differences for tributary and in-lake sites. We observed contrasting total phosphorus (TP) trends between tributary and in-lake locations, where there was no significant (p-value > 0.05) change in tributary TP trends, but significant (p-value < 0.05) increasing TP trends at lake sites. This shows an apparent incongruence of phosphorus-concentration trends flowing into Lake Scugog with in-lake phosphorus trends, and warrants further study. Although in-lake total nitrogen (TN) and nitrate significantly declined over the study period, they were not strongly associated with environmental drivers in contrast to Total Khejdahl nitrogen, which had a strong association with total precipitation. These findings highlight notable trends and shifts in water quality in the Lake Scugog watershed over a time-frame that captured growing urbanization and climate impacts. As a sentinel ecosystem for the Kawartha Lakes and TSW, our results serve as an early-warning of how water quality may change for other inland lakes in Ontario within the context of climate change and increasing land-use pressures.
The Peace-Athabasca Delta, Canada, is the largest freshwater delta in North America, and the traditional territory of the Athabasca Chipewyan First Nation, Mikisew Cree First Nation, and Fort Chipewyan M & eacute;tis Nation, who rely on water-based access to exercise rights and maintain their Way of Life. Non-inclusion of Indigenous Knowledge in development planning has resulted in cumulative water quantity impacts to the Peace-Athabasca Delta, constituting a loss of rights. Navigational losses are partly due to the Crown governments' management of oil sands exploitation and water withdrawals from the Athabasca River. No meaningful navigational protection exists along the Athabasca River corridor and in the Peace-Athabasca Delta. The Nations apply a rights-based monitoring trigger, known as the Aboriginal Extreme Flow, which is the Athabasca River discharge below which widespread and extreme disruption of Traditional use occurs. The Nations require a depth of four feet (122 cm) to sustain access. Ten years of sampling established the Aboriginal Extreme Flow to be 482 m3/s, using Water Survey of Canada gauge 07DA001. This indicator was developed using a braiding of Indigenous and Western knowledge systems, with broad acceptance and shared validation. We describe alterations in river flow over time, apply the Aboriginal Extreme Flow indicator and examine how navigation loss changes during weeks 33-41. Our analysis of the Athabasca River flow dataset reveals a statistically significant increasing trend in lost access of approximately two additional days every five years. Elders who grew up using these rivers to access rights in the fall have experienced lost access of almost three weeks in their lifetime. Governments need to apply the Aboriginal Extreme Flow in their approvals and policies related to the cultural flow needs of the Athabasca River and Peace-Athabasca Delta. Without measures in place, Indigenous rights will continue to be infringed as cumulative impacts grow ever greater in this region.
The water-energy-food (WEF) nexus is an approach for understanding interactions between the three resources to address complex sustainability and development challenges. While WEF nexus studies have been conducted globally, Canada provides a unique context as one of the most water-rich countries in the world. Yet, there has been limited literature studying the WEF nexus within Canada. Therefore, this study conducts a systematic literature review, using the PRISMA approach, to investigate the landscape of WEF nexus research in Canada. The literature review finds that the studies mostly use quantitative methods of inquiry, mostly focus on national and provincial spatial scales over more local scales, and mostly focus on the WEF nexus as an analytical tool to measure physical resource flows between the resources rather than on policy or governance considerations. Based on these findings, there are four recommendations for future research on the WEF nexus in Canada: (1) more nexus research should be conducted at the local level, (2) more social science and qualitative approaches should be applied in WEF nexus studies, (3) WEF nexus research should investigate resource governance questions, and (4) WEF nexus research should integrated related areas such as climate change, biodiversity loss, and Indigenous sovereignty.
This paper provides an analysis of Ontario's Permits to Take Water (PTTW) from 1960 to 2022, a period marked by profound shifts in environmental policy, technological advancement, economic development and growing ecological awareness. Through a detailed examination of data obtained from the Government of Ontario's open data portal, this study investigates the distribution, issuance, and trends related to water permits across the province, exploring the evolution of water use and relevant policy insights. Our findings reveal significant sectoral and regional variations in permitted water use, influenced by diverse water users, various water use activities, and evolving permit policies. Over time, the province has seen an increase in the number, distribution, and sources of water permits, highlighting potential implications for water resource sustainability, policy and management. By employing geospatial and statistical analysis, this research identifies critical trends in water permit allocations offering insights into the complex interplay between policy, permitting, water use and sustainability. These findings offer insights and guidance for policymakers, including identifying high-demand areas for proactive water policy and management, improving permit data, categorization and reporting practices, and aligning water use monitoring with sustainability objectives. This paper aims to bridge the gap from permits to policy, presenting evidence-based policy insights and recommendations aimed at refining open data and the permitting process to enhance water resource management. The article also presents a framework that can be used to analyze open water permit data in other jurisdictions across Canada.
Groundwater is vital to sustainability in Ontario and Canada. It is a source of water for agriculture, industrial, commercial organizations, hundreds of communities and millions of residents. Despite its significance, the management of groundwater faces substantial challenges, including knowledge gaps, contamination risks, and climate change impacts. This study examines groundwater use in Ontario through the analysis of two open datasets: the Ontario Permit to Take Water (PTTW) dataset, covering the period from 1960 to 2022, and the Reported Water Use dataset, which includes data on the most recent water usage reports from 2020. Using statistical and geospatial analyses, this research identifies patterns in water permit allocation and utilization, providing an analysis of permit data and the critical role of groundwater in Ontario's economy and water supply. Findings reveal significant groundwater use and important regional and sectoral variations highlighting the necessity for integrated policy and management practices that consider groundwater more centrally in the allocation of Ontario's water. The study also underscores the importance of open, transparent water data as the foundation for sustainable management and stakeholder engagement to enhance water governance. Finally, the paper provides some policy recommendations stemming from the data analysis related to water resource management and suggests directions for future research to ensure sustainable groundwater use aligns with broader environmental, economic and social objectives.
Peat-based biofilters have been used to treat septic tank effluent for decades but few studies investigate their longevity. Similarly, long-term performance evaluations of medium-scale decentralized wastewater treatment systems in Indigenous communities are rare. The community-led study described herein assesses five peat moss biofilters installed in Six Nations of the Grand River. The assessment compares sample data with contemporary performance-based classification standards for advanced treatment devices. The results indicate the peat moss filter media is continuing to provide physical, chemical, and biological treatment beyond its expected lifespan, but also that most systems are underperforming. The findings demonstrate without basic maintenance structural components may degrade faster than peat moss, which impacts system monitoring and operation. Routine inspection and maintenance of advanced treatment devices are necessary to ensure they maintain their performance, necessitating funding for such activities. It was also found the older systems exhibited poor denitrification. Such findings support recent literature asserting that peat-based systems cannot independently provide stable and consistent levels of disinfection and nutrient removal to meet standardized performance thresholds. Nevertheless, for advanced levels of Basic Treatment, peat-based systems may continue to be a viable solution for Six Nations if maintained adequately, especially in areas unsuitable for conventional septic systems. Les biofiltres & agrave; base de tourbe sont utilis & eacute;s depuis des d & eacute;cennies pour traiter les effluents de fosses septiques, mais peu d'& eacute;tudes s'int & eacute;ressent & agrave; leur long & eacute;vit & eacute;. De m & ecirc;me, les & eacute;valuations & agrave; long terme des performances des syst & egrave;mes d & eacute;centralis & eacute;s de traitement des eaux us & eacute;es & agrave; moyenne & eacute;chelle dans les communaut & eacute;s autochtones sont rares. L'& eacute;tude men & eacute;e par la communaut & eacute; et d & eacute;crite ici & eacute;value cinq biofiltres & agrave; mousse de tourbe install & eacute;s & agrave; Six Nations of the Grand River. L'& eacute;valuation compare les donn & eacute;es d'& eacute;chantillons avec les normes de classification contemporaines bas & eacute;es sur la performance des dispositifs de traitement avanc & eacute;. Les r & eacute;sultats indiquent que le milieu filtrant en mousse de tourbe continue de fournir un traitement physique, chimique et biologique au-del & agrave; de sa dur & eacute;e de vie pr & eacute;vue, mais aussi que la plupart des syst & egrave;mes sont sous-performants. Les r & eacute;sultats d & eacute;montrent que, sans entretien de base, les composants structurels peuvent se d & eacute;grader plus rapidement que la mousse de tourbe, ce qui a un impact sur la surveillance et le fonctionnement du syst & egrave;me. Une inspection et un entretien de routine des dispositifs de traitement avanc & eacute; sont n & eacute;cessaires pour garantir le maintien de leurs performances, n & eacute;cessitant un financement pour de telles activit & eacute;s. Il a & eacute;galement & eacute;t & eacute; constat & eacute; que les syst & egrave;mes plus anciens pr & eacute;sentaient une mauvaise d & eacute;nitrification. Ces conclusions soutiennent la litt & eacute;rature r & eacute;cente affirmant que les syst & egrave;mes & agrave; base de tourbe ne peuvent pas fournir ind & eacute;pendamment des niveaux stables et coh & eacute;rents de d & eacute;sinfection et d'& eacute;limination des nutriments pour atteindre des seuils de performance normalis & eacute;s. N & eacute;anmoins, pour les niveaux avanc & eacute;s de Traitement de Base, les syst & egrave;mes & agrave; base de tourbe pourraient continuer & agrave; & ecirc;tre une solution viable pour Six Nations s'ils sont entretenus de mani & egrave;re ad & eacute;quate, en particulier dans les zones o & ugrave; les syst & egrave;mes septiques conventionnels ne conviennent pas.
This paper aims to develop a framework for assessing cross-sectoral water demand over a long-term planning horizon using a Water Evaluation and Planning (WEAP) model for the energy sector and integrating it with the assessment of greenhouse gas (GHG) emissions. This framework spatially associates surface and ground water supply resources with sectoral water demand between 2005 and 2050. The developed framework uses a hybrid top-down and bottom-up approach for linking water use in the municipal, commercial, oil and gas, power, industrial, and agriculture sectors with their water sources. Annual water use associated with future changes in population, oil sands production (in situ and surface mining), power generation fuels and technologies, and agricultural and livestock population is quantified. A case study for Alberta was conducted. Eleven future scenarios were evaluated, and model results show that the water demand might increase by 11-25% from the 2020 demand by 2050. The developed framework can be used to provide insights into patterns of water demand and supply for the energy sector as well as other sectors in different scenarios and can be integrated with assessments of GHG emissions, which can aid in decision-making at the provincial and national levels. This framework can be used for other jurisdictions. Cet article vise & agrave; d & eacute;velopper un cadre pour & eacute;valuer la demande en eau intersectorielle sur un horizon de planification & agrave; long terme en utilisant un mod & egrave;le d'& Eacute;valuation et de Planification de l'Eau (WEAP) pour le secteur de l'& eacute;nergie et en l'int & eacute;grant avec l'& eacute;valuation des & eacute;missions de gaz & agrave; effet de serre (GES). Ce cadre associe spatialement les ressources d'approvisionnement en eau de surface et souterraine avec la demande en eau sectorielle entre 2005 et 2050. Le cadre d & eacute;velopp & eacute; utilise une approche hybride descendante et ascendante pour lier l'utilisation de l'eau dans les secteurs municipal, commercial, p & eacute;trolier et gazier, & eacute;lectrique, industriel et agricole avec leurs sources d'eau. L'utilisation annuelle de l'eau associ & eacute;e aux changements futurs dans la population, la production de sables bitumineux (in situ et extraction & agrave; ciel ouvert), les carburants et technologies de g & eacute;n & eacute;ration d'& eacute;lectricit & eacute;, ainsi que la population agricole et d'& eacute;levage est quantifi & eacute;e. Une & eacute;tude de cas pour la province canadienne riche en & eacute;nergie de l'Alberta a & eacute;t & eacute; men & eacute;e. Onze sc & eacute;narios futurs ont & eacute;t & eacute; & eacute;valu & eacute;s, et les r & eacute;sultats du mod & egrave;le montrent que la demande en eau pourrait augmenter de 11 & agrave; 25% par rapport & agrave; la demande de 2020 d'ici 2050. Le cadre d & eacute;velopp & eacute; peut & ecirc;tre utilis & eacute; pour fournir des aper & ccedil;us sur les mod & egrave;les de demande et d'offre en eau pour le secteur de l'& eacute;nergie ainsi que pour d'autres secteurs dans diff & eacute;rents sc & eacute;narios et peut & ecirc;tre int & eacute;gr & eacute; avec des & eacute;valuations des & eacute;missions de GES, ce qui peut aider & agrave; la prise de d & eacute;cision aux niveaux provincial et national. Il s'agit d'un cadre unique qui peut & ecirc;tre utilis & eacute; globalement.
Despite recent advances, streamflow ensemble forecasting systems often suffer from unreliability and under-dispersion. Improving flood forecasting quality benefits decision-makers and the public. Statistical processing methods can enhance raw forecasts. Therefore, identifying the most effective scenario among pre-processing, post-processing, or a combination of both is crucial. While most studies have focused on lumped models, more comprehensive analysis is needed for systems employing spatially distributed models. This study evaluates scenarios involving the pre-processing of both temperature and precipitation forecasts and the post-processing of streamflow forecasts in a streamflow ensemble forecasting system with a spatially distributed hydrological model. It also explores the impact of incorporating flood events and the length of the training data on the performnace of pre- and post-processing approaches through various training and validation strategies. Weighted Ensemble Dressing (WED) is coupled with two bias correction methods: Cumulative Distribution Function Matching (CDFM) and Event Bias Correction (EBC). The forecast assessment covers lead times of 1-5 days for the au Saumon watershed in southern Quebec, Canada. Although pre-processing alone marginally improves raw forecasts, it fails to fully compensate for bias in under-dispersed ensemble forecasts. The combined pre- and post-processing approach proves superior in forecast skill and reliability to other scenarios. These findings align with existing literature, reinforcing the validity of the applied methodologies within current hydrological research. Both bias correction methodsperform well with WED; CDFM is more reliable for short lead times, while EBC excels at longer lead times. Notably, incorporating flood events and optimizing data length further improve processing performance, highlighting the importance of effective data strategies in streamflow forecasting. Malgr & eacute; des progr & egrave;s r & eacute;cents, les syst & egrave;mes de pr & eacute;vision d'ensemble des d & eacute;bits fluviaux souffrent souvent de probl & egrave;mes de fiabilit & eacute; et de sous-dispersion. L'am & eacute;lioration de la qualit & eacute; des pr & eacute;visions des crues profite aux d & eacute;cideurs et au grand public. Les m & eacute;thodes statistiques de traitement peuvent am & eacute;liorer les pr & eacute;visions brutes, ce qui rend crucial l'identification du sc & eacute;nario le plus efficace parmi le pr & eacute;-traitement, le post-traitement, ou leur combinaison. Alors que la plupart des & eacute;tudes se concentrent sur des mod & egrave;les globalis & eacute;s, une analyse plus approfondie est n & eacute;cessaire pour les syst & egrave;mes utilisant des mod & egrave;les hydrologiques distribu & eacute;s spatialement. Cette & eacute;tude & eacute;value diff & eacute;rents sc & eacute;narios impliquant le pr & eacute;-traitement des pr & eacute;visions de temp & eacute;rature et de pr & eacute;cipitations, ainsi que le post-traitement des pr & eacute;visions de d & eacute;bits, dans un syst & egrave;me de pr & eacute;vision d'ensemble des d & eacute;bits reposant sur un mod & egrave;le hydrologique distribu & eacute; spatialement. Elle explore & eacute;galement l'impact de l'int & eacute;gration des & eacute;v & eacute;nements de crue et de la longueur des donn & eacute;es d'entra & icirc;nement sur la performance des approches de pr & eacute;- et post-traitement, & agrave; travers diverses strat & eacute;gies d'entra & icirc;nement et de validation. Le Weighted Ensemble Dressing (WED) est coupl & eacute; & agrave; deux m & eacute;thodes de correction des biais : le Cumulative Distribution Function Matching (CDFM) et la correction des biais d'& eacute;v & eacute;nement (Event Bias Correction, EBC). La performance des pr & eacute;visions est & eacute;valu & eacute;e pour des horizons de 1 & agrave; 5 jours dans le bassin versant de la rivi & egrave;re au Saumon, au sud du Qu & eacute;bec, Canada. Le pr & eacute;-traitement am & eacute;liore marginalement les pr & eacute;visions brutes, mais ne corrige pas enti & egrave;rement les biais dans les ensembles sous-dispers & eacute;s. L'approche combin & eacute;e de pr & eacute;- et post-traitement am & eacute;liore significativement la comp & eacute;tence et la fiabilit & eacute; des pr & eacute;visions, surpassant les autres sc & eacute;narios. Ces r & eacute;sultats concordent avec la litt & eacute;rature existante, renfor & ccedil;ant la robustesse des m & eacute;thodologies appliqu & eacute;es dans la recherche hydrologique actuelle. Les deux m & eacute;thodes de correction des biais fonctionnent bien avec WED ; le CDFM est plus fiable pour les horizons courts, tandis que l'EBC excelle pour les horizons plus longs. L'int & eacute;gration des & eacute;v & eacute;nements de crue et l'optimisation de la longueur des donn & eacute;es am & eacute;liorent en outre la performance du traitement, soulignant l'importance de strat & eacute;gies efficaces de gestion des donn & eacute;es dans la pr & eacute;vision des d & eacute;bits.
This article synthesizes the water quality hedonic property literature and develops a Canadian freshwater amenity valuation model to derive spatially explicit national benefit estimates. We use over 600 meta-observations from 29 hedonic price studies to estimate price elasticities for changes in water quality measured by Secchi disk depth. We find that a 10% increase in water quality is associated with a 1.60% price increase for residential properties within 500 meters of the lakeshore. A distance-decay effect is observed, with a smaller price premium of 0.08% for properties located 500 to 1,000 meters from the lakeshore. These elasticities are integrated with spatial data to estimate the amenity values of a potential 10% water quality improvement across Canada's freshwater lakes. The estimated local amenity benefits total $8.2 billion, with Ontario receiving 55% of the benefits and British Columbia experiencing the highest per-household gain among the provinces.
The world is entering an era of immense water-related threats, from floods, droughts, and other extreme events to degradation of water quality and severe pressure on aquatic ecosystems, increasing demand for freshwater, and major changes in hydrological regime and water availability. There is a need for new science, new modelling tools and monitoring systems, and more effective mechanisms to translate new scientific knowledge into societal action. This represents a grand challenge for water science in Canada and globally: 'How can we best prepare for and manage water futures in the face of dramatically increasing risks?' The Global Water Futures (GWF) programme was conceived in 2015 to address this grand challenge; funded by the Canada First Research Excellence Fund and bringing together a transdisciplinary team of partners from 18 Canadian universities working with over 500 other partner institutions and organisations, GWF was the largest programme of its kind in Canada, and to our knowledge the largest in the world. As the programme ended in August 2025 this paper looks back at how GWF was conceived and developed, it's management and operation, how it was structured to pursue an ambitious science agenda and how this was carried out, Indigenous engagement and knowledge exchange within GWF, changes in direction and approach as GWF evolved and circumstances arose, and lessons learned upon reflection. This was a vast effort by a large group of people and many partners and much of what was done was new and unique. By documenting our experience, this paper aims to serve as a useful guide for large science programmes.
Concerns over per- and polyfluoroalkyl substances (PFASs) contamination of water continue to grow as more PFASs are found in more places and related guideline concentrations generally decline. Reports on the occurrence of PFASs in groundwater from around the globe have been published in scientific journals for over two decades now. Much of this work originates from the United States, China, and European countries. In this review, we investigated the state of studies publishing data on PFAS concentrations in groundwater or identifying PFAS sources to groundwater in Canada. We found and report on only 11 studies in scientific journals (by mid-2024), and the majority of these had linkages (direct or collaborative research, funding, or other key support) to federal or provincial governments. Potential reasons behind there being so few studies are discussed. Additionally, we pose and examine four key questions that highlight areas needing greater investigation in Canada. These are: (1) What is the state of PFASs in groundwater-sourced drinking water across the country? (2) What are background PFASs concentrations for groundwater? (3) What is the prevalence and distribution of PFASs sources to groundwater and risk posed by them? 4. How important is groundwater transport of PFASs to surface waters and aquatic ecosystems? Les pr & eacute;occupations relatives & agrave; la contamination de l'eau par les substances per- et polyfluoroalkyl & eacute;es (PFAS) continuent de cro & icirc;tre & agrave; mesure que l'on trouve davantage de PFAS dans un plus grand nombre d'endroits et que les concentrations recommand & eacute;es dans les directives diminuent de mani & egrave;re g & eacute;n & eacute;rale. Depuis plus de deux d & eacute;cennies, des rapports sur la pr & eacute;sence de PFAS dans les eaux souterraines & agrave; travers le monde sont publi & eacute;s dans des revues scientifiques. La plupart de ces travaux proviennent des & Eacute;tats-Unis, de la Chine et de pays europ & eacute;ens. Dans cette & eacute;tude, nous avons examin & eacute; l'& eacute;tat des recherches publiant des donn & eacute;es sur les concentrations de PFAS dans les eaux souterraines ou identifiant les sources de PFAS dans les eaux souterraines au Canada. Nous n'avons trouv & eacute; et rapport & eacute; que 11 & eacute;tudes publi & eacute;es dans des revues scientifiques, dont la majorit & eacute; avaient des liens (recherche directe ou collaborative, financement ou autre soutien important) avec les gouvernements f & eacute;d & eacute;ral ou provinciaux. Les raisons potentielles de ce faible nombre d'& eacute;tudes sont examin & eacute;es. En outre, nous posons et examinons quatre questions cl & eacute;s qui mettent en & eacute;vidence les domaines n & eacute;cessitant des recherches plus approfondies au Canada. Ces questions sont les suivantes : 1. Quelle est la situation des PFAS dans l'eau potable provenant des eaux souterraines & agrave; travers le pays ? 2. Quelles sont les concentrations de fond des PFAS dans les eaux souterraines ? 3. Quelle est la pr & eacute;valence et la r & eacute;partition des sources de PFAS dans les eaux souterraines et quels sont les risques qu'elles pr & eacute;sentent ? 4. Quelle est l'importance du transport des PFAS par les eaux souterraines vers les eaux de surface et les & eacute;cosyst & egrave;mes aquatiques ?
Spanning 750,000 km2 across the Northern Great Plains of North America, the Prairie Potholes Region (PPR) is characterized by millions of shallow wetlands, forming a unique ecosystem that provides habitat for wildlife, carbon storage, and flood control. However, the presence and persistence of Prairie Pothole wetlands is vulnerable to the increasing effects of climate change and land use. Knowledge of northern Great Plains prairie wetland hydrology is based primarily on a few long-term research stations, but generalizing from these intensively monitored areas to the entire PPR requires application of synoptic hydrological approaches across a spatially extensive dataset. The aim of this study is to assess the relative importance of input water sources and evaporative water loss on prairie pothole wetlands of varying permanence class in the Parkland and Grassland Natural Regions in Alberta (Canada). We compare a normal precipitation year (2014) and a relatively dry year (2015), as well as comparing natural sites to 24 restored wetlands. Water samples were collected at intervals during May-August of both years and analyzed for oxygen and hydrogen isotope composition. A combination isotope-mass balance and Bayesian approach was used to generate hydrologic metrics including the isotope composition of input water and evaporation to inflow ratio. Temporal synchrony was tested among the years and site types. We observed little difference in wetland hydrology between the Grassland and Parkland during a normal climate year, but under drier conditions Grassland sites were more vulnerable to evaporation. High synchrony across the study regions indicates that climate change will likely affect wetlands similarly, while restored sites may be less vulnerable to drawdown than natural sites. Interestingly, restored wetlands were more resistant to drawdown than natural wetlands in the Parkland, which will have consequences for wetland biota and climate change adaptation in the northwestern PPR. S'& eacute;tendant sur 750 000 km(2) dans les Grandes Plaines du Nord de l'Am & eacute;rique du Nord, la r & eacute;gion des cuvettes des Prairies (RCP) se caract & eacute;rise par des millions de zones humides peu profondes, formant un & eacute;cosyst & egrave;me unique qui offre un habitat & agrave; la faune, un stockage de carbone et un contr & ocirc;le des inondations. Cependant, la pr & eacute;sence et la persistance de ces zones humides sont vuln & eacute;rables aux effets croissants du changement climatique et de l'utilisation des terres. La connaissance de l'hydrologie des zones humides des prairies des Grandes Plaines du Nord repose principalement sur quelques stations de recherche & agrave; long terme, mais la g & eacute;n & eacute;ralisation de ces zones intens & eacute;ment surveill & eacute;es & agrave; l'ensemble de la RCP n & eacute;cessite l'application d'approches hydrologiques synoptiques sur un ensemble de donn & eacute;es spatialement & eacute;tendu. L'objectif de cette & eacute;tude est d'& eacute;valuer l'importance relative des sources d'eau d'apport et des pertes d'eau par & eacute;vaporation dans les zones humides des cuvettes des Prairies de diff & eacute;rentes classes de permanence dans les r & eacute;gions naturelles des parcs et des prairies de l'Alberta (Canada). Nous comparons une ann & eacute;e de pr & eacute;cipitations normales (2014) et une ann & eacute;e relativement s & egrave;che (2015), ainsi que des sites naturels & agrave; 24 zones humides restaur & eacute;es. Des & eacute;chantillons d'eau ont & eacute;t & eacute; pr & eacute;lev & eacute;s & agrave; intervalles r & eacute;guliers entre mai et ao & ucirc;t des deux ann & eacute;es et analys & eacute;s pour d & eacute;terminer leur composition isotopique en oxyg & egrave;ne et en hydrog & egrave;ne. Une approche combinant bilan isotopique et massique et bay & eacute;sienne a & eacute;t & eacute; utilis & eacute;e pour g & eacute;n & eacute;rer des param & egrave;tres hydrologiques, notamment la composition isotopique de l'eau d'entr & eacute;e et le rapport & eacute;vaporation/apport. La synchronicit & eacute; temporelle a & eacute;t & eacute; test & eacute;e entre les ann & eacute;es et les types de sites. Nous avons observ & eacute; peu de diff & eacute;rences dans l'hydrologie des zones humides entre les prairies et les parcs lors d'une ann & eacute;e climatique normale, mais dans des conditions plus s & egrave;ches, les sites de prairies & eacute;taient plus vuln & eacute;rables & agrave; l'& eacute;vaporation. La forte synchronicit & eacute; entre les r & eacute;gions & eacute;tudi & eacute;es indique que le changement climatique affectera probablement les zones humides de la m & ecirc;me mani & egrave;re, tandis que les sites restaur & eacute;s pourraient & ecirc;tre moins vuln & eacute;rables au rabattement que les sites naturels. Il est int & eacute;ressant de noter que les zones humides restaur & eacute;es & eacute;taient plus r & eacute;sistantes au rabattement que les zones humides naturelles dans les parcs, ce qui aura des cons & eacute;quences sur le biote des zones humides et l'adaptation au changement climatique dans la PPR du nord-ouest.
Climate change has increased the frequency and intensity of wildfires in British Columbia, causing debris floods (i.e. floods with relatively high sediment concentrations) in environments that do not typically experience them. A physical model was used to explore the impacts of debris floods on the morphology and geohazard distribution of an alluvial fan built by floods with lower sediment concentrations. The model was not scaled to a specific real-world prototype but represents a generic class of streams that have a gravel/cobble fan with a gradient of about 6%. Fan topography was surveyed every 30 min using digital photogrammetry, and surface changes were documented via time-lapse video. High sediment concentration debris floods initially infilled the pre-existing channel and aggraded the upper fan, increasing the average fan slope, particularly at the apex. A return to floods with low sediment concentrations following the debris floods caused the channel to incise in the upper fan, disconnecting the channel from the fan surface at the apex, and returning the channel to its pre-debris flood gradient. Repeated sequences of debris floods and floods produced cycles of aggradation and incision that increasingly confined the stream at the fan apex. The result of this increased confinement was to restrict bank erosion and channel migration to the middle part of the fan, leaving the flanks relatively inactive. The experiments demonstrate how the dynamics of sediment deposition and erosion at the fan apex during one debris flood can constrain subsequent channel activity and change the proportion of the fan that is impacted by a subsequent debris flood. Le changement climatique a augment & eacute; la fr & eacute;quence et l'intensit & eacute; des incendies de for & ecirc;t en Colombie-Britannique, entra & icirc;nant des crues de d & eacute;bris (c'est-& agrave;-dire des crues avec des concentrations & eacute;lev & eacute;es de s & eacute;diments) dans des environnements qui n'en connaissent g & eacute;n & eacute;ralement pas. Un mod & egrave;le physique a & eacute;t & eacute; utilis & eacute; pour explorer les effets de ces crues de d & eacute;bris sur la morphologie et la distribution des g & eacute;orisques d'un c & ocirc;ne alluvial form & eacute; par des crues & agrave; plus faible concentration en s & eacute;diments. Le mod & egrave;le n'est pas & agrave; l'& eacute;chelle d'un prototype r & eacute;el, mais repr & eacute;sente une classe g & eacute;n & eacute;rique de cours d'eau pr & eacute;sentant un c & ocirc;ne de gravier/galet avec une pente d'environ 6 %. La topographie du c & ocirc;ne a & eacute;t & eacute; relev & eacute;e toutes les 30 minutes par photogramm & eacute;trie num & eacute;rique, et les changements de surface ont & eacute;t & eacute; document & eacute;s & agrave; l'aide de vid & eacute;os en acc & eacute;l & eacute;r & eacute;. Les crues de d & eacute;bris & agrave; forte concentration en s & eacute;diments ont d'abord combl & eacute; le chenal pr & eacute;existant et sur & eacute;lev & eacute; la partie amont du c & ocirc;ne, augmentant ainsi la pente moyenne, en particulier & agrave; l'apex. Le retour & agrave; des crues faiblement charg & eacute;es apr & egrave;s les crues de d & eacute;bris a entra & icirc;n & eacute; l'incision du chenal dans la partie amont du c & ocirc;ne, d & eacute;connectant le chenal de la surface & agrave; l'apex et r & eacute;tablissant sa pente d'avant-crue de d & eacute;bris. Les s & eacute;quences r & eacute;p & eacute;t & eacute;es de crues de d & eacute;bris et de crues classiques ont produit des cycles d'aggradation et d'incision qui ont progressivement confin & eacute; le cours d'eau & agrave; l'apex. Cette plus grande contrainte a eu pour effet de limiter l'& eacute;rosion lat & eacute;rale et la migration du chenal & agrave; la partie m & eacute;diane du c & ocirc;ne, laissant les flancs relativement inactifs. Ces exp & eacute;riences montrent comment les dynamiques de d & eacute;p & ocirc;t et d'& eacute;rosion & agrave; l'apex lors d'une crue de d & eacute;bris peuvent conditionner l'& eacute;volution ult & eacute;rieure du chenal et modifier la portion du c & ocirc;ne affect & eacute;e par les crues suivantes.
Freshwater quality is a pillar of water security worldwide as countries are becoming increasingly impacted by contaminants and nutrient loads from human activity, as well as landscape and climate changes. Reliable water quality predictions play a fundamental role in tackling this problem. However, water quality predictions are currently unavailable for most global rivers and lakes, including those in Canada. Environment and Climate Change Canada (ECCC) and its partners present here the vision for a physics-based National Water Quality Model (Nat-WQE; National(e) Water Quality/Qualit & eacute; de l'Eau) that aims to deliver simulations and predictions of water quality across timescales from days to decades by building on existing environmental modelling systems and field data. This commentary also introduces the National Water Quality Modelling Framework (NWQMF) that has been maturing over the years and provides the basis and vision for a robust Nat-WQE capable of delivering short- to long-term predictions of water quality parameters, informing decisions on effluent concentration limits, and acting as a source-water warning system for Canadians. The NWQMF will produce critical information that will be available to interested users to inform decisions at various levels, from local communities to nationwide to international efforts. In this commentary, we summarize (1) the overarching vision and desired outcomes of the NWQMF and Nat-WQE, (2) a summary of lessons from other large-scale water quality modelling efforts which informed the modelling philosophy, framework, structure, and associated data requirements, and (3) the implementation plan, including identifying challenges and opportunities/synergies for national and international collaborations.
