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Climate change is driving the loss of alpine glaciers globally, yet investigations about the water quality of rivers stemming from them are few. Here we provide an overview assessment of a biogeochemical data set containing 200+ parameters that we collected between 2019 and 2021 from the headwaters of three such rivers (Sunwapta‐Athabasca, North Saskatchewan, and Bow) which originate from the glacierized eastern slopes of the Canadian Rocky Mountains. We used regional hydrometric data sets to accurately model discharge at our 14 sampling sites. We created a Local Meteoric Water Line (LMWL) using riverine water isotope signatures and compared it to collected regional rain, snow, and glacial ice signatures. Principal component analyses of river physicochemical measures revealed distance from glacier explained more data variability than other spatiotemporal factors (i.e., season, year, or river). Discharge, chemical concentrations, and watershed areas were then used to model site‐specific open water season yields for 25 parameters. Chemical yields followed what would generally be expected along river continuums from glacierized to montane altitudinal life zones, with landscape characteristics driving chemical sources and sinks. For instance, particulate chemical yields were generally highest near source glaciers with proglacial lakes acting as settling ponds, whereas most dissolved yields varied by parameter and site. As these headwaters continue to evolve with glacier mass loss, the data set and analyses presented here can be used as a contemporary baseline to mark future change against. Further, following this initial assessment of our data set, we encourage others to mine it for additional biogeochemical studies. Plain Language Summary: Alpine glaciers are vulnerable to climate change, with their numbers and sizes expected to decline dramatically within the current century. It is known that a decrease in glacier mass will have direct consequences on glacial meltwater quantity, but how this may impact the quality of receiving freshwaters is less understood. Our goal was to record a water quality data set of 200+ physical and chemical parameters for the headwaters of three major rivers draining glaciers on the eastern slopes of the Canadian Rocky Mountains. We first used statistics to model how fast the rivers were flowing at our 14 sampling locations over our 2‐year sampling period. We then looked at how and why water isotopes collected from river, rain, snow, and glacier ice samples differed. We discovered that distance downstream from the glacier explained more statistical variation in our physical and chemical measures than season, year, or river. Finally, at each of our sampling sites, we calculated chemical yields, or the amount of chemical constituent being exported downriver per unit watershed area, and found landscape features like lakes, outwash plains, and forests influence them. We ultimately hope that others use our comprehensive data set to investigate this changing region further. Key Points: We assessed a 200+ parameter data set collected from glacial river headwaters on the eastern slopes of the Canadian Rocky MountainsOur findings can act as a contemporary reference for future investigation of glacial headwaters in rapidly evolving alpine regionsThe possibilities for data exploration of our 260,000+ measure data set are numerous and we encourage others to mine it for new studies [ABSTRACT FROM AUTHOR]

This study examines the hydrological recovery of two regenerating boreal trembling aspen (Populus tremuloides Michx.) dominated stands and the sensitivity of that regeneration to drought within the first 5 years of establishment. The results indicate that evapotranspiration fluxes and water-use efficiency rebounded quickly as a result of new vegetation foliage growth and wet conditions found within the first 2 years following the harvest. However, a period of dry years had a significant influence on rates of postharvest growth, carbon dioxide (C[O.sub.2]), and water fluxes at these sites. The northern study area (NSA) and southern study area (SSA) were harvested in the winters of 2007 and 2008, respectively. The first and second years of regeneration at the SSA and NSA, respectively, were marked by an early spring thaw and higher-than-normal precipitation, while air temperatures remained slightly above the 30-year normal. During this period, mean measured height of vegetation tripled at both sites, and cumulative evapotranspiration was approximately 60% of that prior to harvest by the end of the second year of growth. By the third year (2009), the NSA became a sink for atmospheric C[O.sub.2] during the snow free season (days of the year 128- 238) despite low precipitation during the latter half of the summer. Volumetric soil moisture content in 2009 was the highest (on average) of the 5 years examined due to heavy snowfall and a late start to the growing season (where air temperatures consistently exceeded 0°C), resulting in sustained productivity. However, cumulative annual precipitation also declined to 79% and 57% in 2009 and 2010, respectively, of the 30-year normal for that region, leading to significant (lagged) declines in forest productivity at the NSA in 2010 and 2011. This resulted in the site becoming a source of C[O.sub.2] to the atmosphere during the 2010 and 2011 growing seasons (annual balance was not measured). Throughout the drought period (2009, 2010, and 2011), mean stand height increased by only 15%, 11%, and 14%, respectively, compared with the mean stand height in 2008. Water-use efficiency also declined in 2010 and 2011, whereas differences in light-use efficiency did not vary significantly because foliage was maintained (i.e., leaves did not abscise as a result of drought). The results of this study indicate that regenerating aspen stands are sensitive to drought and respond relatively quickly to changes in the soil moisture regime. This is important because regional drying as a result of predicted climatic changes combined with increased industrial activity may result in significant decline in productivity within these stands over broad regions. Key words: trembling aspen, evapotranspiration, net ecosystem exchange, water-use efficiency, harvest. Cette etude s'interesse a la recuperation hydrologique de deux peuplements boreaux en regeneration domines par le peuplier faux-tremble (Populus tremuloides Michx.) ainsi qu'a la sensibilite de la regeneration a la secheresse au cours des cinq annees suivant son etablissement. Les resultats de cette etude indiquent que le flux d'evapotranspiration (ET) et l'efficacite d'utilisation de l'eau (EUE) se sont rapidement retablis avec la croissance du feuillage de la nouvelle vegetation et les conditions humides observees au cours des deux premieres annees apres la recolte. Cependant, une periode d'annees seches a eu une influence significative sur les taux de croissance postrecolte, de dioxyde de carbone (C[O.sub.2]) et de flux de l'eau dans ces sites. L'aire d'etude septentrionale (AES) et l'aire d'etude meridionale (AEM) ont ete recoltees respectivement durant les hivers 2007 et 2008. La premiere annee de regeneration dans l'AEM et la seconde dans l'AES ont ete marquees par un degel printanier hatif et des precipitations plus elevees que la normale tandis que les temperatures de l'air sont demeurees legerement au-dessus de la normale 30 ans. Durant cette periode, la hauteur moyenne mesuree de la vegetation a triple dans les deux sites et, a la fin de la deuxieme annee de croissance, la valeur cumulative de ET correspondait a environ 60 % de la valeur prerecolte. A la troisieme annee (2009), l'AES est devenue un puits pour le C[O.sub.2] atmospherique pendant la saison exempte de neige (jours de l'annee 128-238) malgre les faibles precipitations durant la derniere moitie de l'ete. Au cours des cinq annees de l'etude, l'humidite volumique du sol (Hv) a ete la plus elevee en 2009 (en moyenne) a cause des chutes de neige importantes et du debut tardif de la saison de croissance (lorsque la temperature de l'air etait constamment au-dessus de 0°C), entrainant une production soutenue. Cependant, la precipitation annuelle cumulative a aussi diminue, atteignant seulement 79 % (2009) et 57 % (2010) de la normale 30 ans dans cette region, ce qui a entraine un declin important (differe) de la production de la foret dans l'AES en 2010 et 2011. Ce site est par consequent devenu une source de C[O.sub.2] atmospherique durant les saisons de croissance de 2010 et 2011 (le bilan annuel n'a pas ete mesure). Durant la periode de secheresse (2009, 2010 et 2011) la hauteur moyenne du peuplement a augmente de seulement 15 % (2009), 11 % (2010) et 14 % (2011) par rapport a 2008. L'EUE a aussi diminue en 2010 et 2011 tandis que les differences dans l'efficacite d'utilisation de la lumiere n'ont pas varie de facon significative parce que le feuillage s'est maintenu (c.-a-d. que les feuilles ne sont pas tombees a cause de la secheresse). Les resultats de cette etude indiquent que les peuplements de peuplier faux-tremble en regeneration sont sensibles a la secheresse et reagissent assez rapidement aux variations du regime d'humidite du sol. Cela est important etant donne que des conditions regionales plus seches a cause des changements climatiques a venir combinees a l'activite industrielle accrue pourraient engendrer un declin de la productivite dans ces peuplements sur de vastes etendues. [Traduit par la Redaction] Mots-cles : peuplier faux-tremble, evapotranspiration, echanges nets de l'ecosysteme, efficacite d'utilisation de l'eau, recolte., Introduction The northern boreal forest covers approximately 29% of North America (Brandt 2009) and is a significant sink for atmospheric carbon dioxide (C[O.sub.2]) due to broad area coverage and the [...]

: To test the hypothesis that seedling growth and water use increase with soil temperature and improved soil area Ton and vary with species, we evaluated the above- and below-ground growth and water use of seedlings of four northern boreal conifer species: black spruce (Pica Mariana (Mill.) B.S.P.), white spruce (Pica glace (Munch) Voss), tamarack (Larynx larrikin (Due Rio) K. Koch), and lodge pole pine (Pinups contort Doug. ex Loud.) grown under different temperature And near-flooded soil conditions. Seedlings were grown in specialized pots that maintained the water table level at either 15 cm (high water table treatment: very wet) or 30 cm (low water table treatment: moderately wet) below the soil surface, and whole-seedling transpiration was assessed. Soil temperature (5, 10, or 20°C) was controlled with a water bath surrounding the pots. Although some species were sensitive to the high water table treatment, soil temperature was the driver of seedling growth and water use. We ranked the ability of the seedlings of the species to tolerate the cold soil conditions examined as black spruce > lodgepole pine > tamarack > white spruce. The ranking of the ability to tolerate near-flooded conditions was tamarack and lodgepole pine > black spruce > white spruce. Resume: Pour tester l'hypothese que la croissance et l'utilisation de l'eau par les semis augmentent avec la temperature dusol et une meilleure aeration du sol, nous avons evalue la croissance aerienne et souterraine et l'utilisation de l'eau par les semis de quatre especes boreales de conifere: l'epinette noire (Picea mariana (Mill.) B.S.P.), l'epinette blanche (Picea glauca (Moench) Voss), le meleze laricin (Larix laricina (Du Roi) K. Koch) et le pin tordu (Pinus contorta Dougl. exLoud.) cultives a differentes temperatures dans un sol quasi inonde. Les semis ont ete cultives dans des pots speciaux qui maintenaient le niveau de la nappe phreatique soit a 15 cm (niveau de la nappe phreatique eleve: tres humide, soit a 30 cm (niveau de la nappe phreatique bas: moderement humide) sous la surface du sol et la transpiration globale des semis a ete mesuree. La temperature du sol (5, 10 ou 20°C) etait controlee par un bassin d'eau qui contenait les pots. Bien que certai-nes especes fussent sensibles au traitement niveau de la nappe phreatique eleve, la temperature du sol etait le facteur qui de-terminait la croissance des semis etl'utilisation de l'eau. Nous avons classe les differentes especes selon leur capacite a tolerer des conditions de temperature du sol plus froides. On retrouve dans l'ordre de l'espece la plus tolerante a la moins tolerante: l'epinette noire, le pin tordu, le meleze laricin et l'epinette blanche. De la meme facon, selon leur capacite a tole-rer des conditions de quasi-inondation, on retrouve sur le meme pied, le meleze laricin et le pin tordu suivis de l'epinette noire et de l'epinette blanche. [Traduit par la Redaction], Introduction In the boreal plain of North America, many forest sites are located on low-lying areas with flat topography and soils of poor internal drainage. In combination with the cold [...]

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The Western Boreal Plain of North Central Alberta comprises a mosaic of wetlands and aspen ( Populus tremuloides) dominated uplands where precipitation (P) is normally exceeded by evapotranspiration (ET). As such these systems are highly susceptible to the climatic variability that may upset the balance between P and ET. Above canopy evapotranspiration (ETC) and understory evapotranspiration (ETB) were examined using the eddy covariance technique situated at 25.5 m (7.5 m above tree crown) and 4.0 m above the ground surface, respectively. During the peak period of the growing seasons (green periods), ETC averaged 3.08 mm d−1 and 3.45 mm d−1 in 2005 and 2006, respectively, while ETB averaged 1.56 mm d−1 and 1.95 mm d−1. Early in the growing season, ETB was equal to or greater than ETC once understory development had occurred. However, upon tree crown growth, ETB was lessened due to a reduction in available energy. ETB ranged from 42 to 56% of ETC over the remainder of the snow-free seasons. Vapour pressure deficit (VPD) and soil moisture (θ) displayed strong controls on both ETC and ETB. ETC responded to precipitation events as the developed tree crown intercepted and held available water which contributed to peak ETC following precipitation events >10 mm. While both ETC and ETB were shown to respond to VPD, soil moisture in the rooting zone is shown to be the strongest control regardless of atmospheric demand. Further, soil moisture and tension data suggest that rooting zone soil moisture is controlled by the redistribution of soil water by the aspen root system. Copyright © 2013 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

In the Canadian Western Boreal Plain (WBP), wetlands (ponds and peatlands) comprise up to 50% of the landscape and represent unique habitat where summer precipitation is often outpaced by evapotranspiration and hillslope groundwater position does not follow topography. In this sub-humid location, groundwater fluxes and stores in riparian peatlands influence pond water levels and root zone moisture sources for forested uplands. To accurately describe the transport and retention of water in peat, it is important to consider peat subsidence. This paper quantifies the amount and effect of seasonal subsidence in a riparian peatland in the Utikuma Lake region in north-central Alberta, Canada. Results demonstrate that the deep and poorly decomposed peat deposits are resistant to compression, and that thick (and persistent) ground frost hinders pore collapse (shrinkage) above the water table until late summer when the ground has thawed. Even then, subsidence is still limited to the top 50 cm and is not closely related to changes in peatland water table or pond water level. Thus the water balance of these ponds and riparian areas appears to be less sensitive to peat volume changes than it is to the persistence of a substantial frost layer well into the snow-free period. [ABSTRACT FROM AUTHOR]

Abstract unavailable [ABSTRACT FROM AUTHOR]

Wildfires can have severe and lasting impacts on the water quality of aquatic ecosystems. However, our understanding of these impacts is founded primarily from studies of small watersheds with well-connected runoff regimes. Despite the predominance of large, low-relief rivers across the fire-prone Boreal forest, it is unclear to what extent and duration wildfire-related material (e.g., ash) can be observed within these systems that typically buffer upstream disturbance signals. Following the devastating 2016 Fort McMurray wildfire in western Canada, we initiated a multi-faceted water quality monitoring program that suggested brief (hours to days) wildfire signatures could be detected in several large river systems, particularly following rainfall events greater than 10 mm. Continuous monitoring of flow and water quality showed distinct, precipitation-associated signatures of ash transport in rivers draining expansive (800-100,000 km 2 ) and partially-burned (<1-22 percent burned) watersheds, which were not evident in nearby unburned regions. Yields of suspended sediment, nutrients (nitrogen, phosphorus) and metals (lead, others) from impacted rivers were 1.2-10 times greater than from those draining unburned regions. Post-fire suspended sediment concentrations in impacted rivers were often larger than pre-fire 95% prediction intervals based on several years of water sampling. These multiple lines of evidence indicate that low-relief landscapes can mobilize wildfire-related material to rivers similarly, though less-intensively and over shorter durations, than headwater regions. We propose that uneven mixing of heavily-impacted tributaries with high-order rivers may partially explain detection of wildfire signals in these large systems that may impact downstream water users., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Purpose: This review of sediment source fingerprinting assesses the current state-of-the-art, remaining challenges and emerging themes. It combines inputs from international scientists either with track records in the approach or with expertise relevant to progressing the science., Methods: Web of Science and Google Scholar were used to review published papers spanning the period 2013-2019, inclusive, to confirm publication trends in quantities of papers by study area country and the types of tracers used. The most recent (2018-2019, inclusive) papers were also benchmarked using a methodological decision-tree published in 2017., Scope: Areas requiring further research and international consensus on methodological detail are reviewed, and these comprise spatial variability in tracers and corresponding sampling implications for end-members, temporal variability in tracers and sampling implications for end-members and target sediment, tracer conservation and knowledge-based pre-selection, the physico-chemical basis for source discrimination and dissemination of fingerprinting results to stakeholders. Emerging themes are also discussed: novel tracers, concentration-dependence for biomarkers, combining sediment fingerprinting and age-dating, applications to sediment-bound pollutants, incorporation of supportive spatial information to augment discrimination and modelling, aeolian sediment source fingerprinting, integration with process-based models and development of open-access software tools for data processing., Conclusions: The popularity of sediment source fingerprinting continues on an upward trend globally, but with this growth comes issues surrounding lack of standardisation and procedural diversity. Nonetheless, the last 2 years have also evidenced growing uptake of critical requirements for robust applications and this review is intended to signpost investigators, both old and new, towards these benchmarks and remaining research challenges for, and emerging options for different applications of, the fingerprinting approach., Competing Interests: Conflict of interestThe authors declare that they have no conflicts of interest., (© The Author(s) 2020.)

Global increases in the occurrence of large, severe wildfires in forested watersheds threaten drinking water supplies and aquatic ecology. Wildfire effects on water quality, particularly nutrient levels and forms, can be significant. The longevity and downstream propagation of these effects as well as the geochemical mechanisms regulating them remain largely undocumented at larger river basin scales. Here, phosphorus (P) speciation and sorption behavior of suspended sediment were examined in two river basins impacted by a severe wildfire in southern Alberta, Canada. Fine-grained suspended sediments (<125 μm) were sampled continuously during ice-free conditions over a two-year period (2009-2010), 6 and 7 years after the wildfire. Suspended sediment samples were collected from upstream reference (unburned) river reaches, multiple tributaries within the burned areas, and from reaches downstream of the burned areas, in the Crowsnest and Castle River basins. Total particulate phosphorus (TPP) and particulate phosphorus forms (nonapatite inorganic P, apatite P, organic P), and the equilibrium phosphorus concentration (EPC0 ) of suspended sediment were assessed. Concentrations of TPP and the EPC0 were significantly higher downstream of wildfire-impacted areas compared to reference (unburned) upstream river reaches. Sediments from the burned tributary inputs contained higher levels of bioavailable particulate P (NAIP) - these effects were also observed downstream at larger river basin scales. The release of bioavailable P from postfire, P-enriched fine sediment is a key mechanism causing these effects in gravel-bed rivers at larger basin scales. Wildfire-associated increases in NAIP and the EPC0 persisted 6 and 7 years after wildfire. Accordingly, this work demonstrated that fine sediment in gravel-bed rivers is a significant, long-term source of in-stream bioavailable P that contributes to a legacy of wildfire impacts on downstream water quality, aquatic ecology, and drinking water treatability., (© 2015 John Wiley & Sons Ltd.)

In many parts of the world, forests provide high quality water for domestic, agricultural, industrial, and ecological needs, with water supplies in those regions inextricably linked to forest health. Wildfires have the potential to have devastating effects on aquatic ecosystems and community drinking water supply through impacts on water quantity and quality. In recent decades, a combination of fuel load accumulation, climate change, extensive droughts, and increased human presence in forests have resulted in increases in area burned and wildfire severity-a trend predicted to continue. Thus, the implications of wildfire for many downstream water uses are increasingly concerning, particularly the provision of safe drinking water, which may require additional treatment infrastructure and increased operations and maintenance costs in communities downstream of impacted landscapes. A better understanding of the effects of wildfire on water is needed to develop effective adaptation and mitigation strategies to protect globally critical water supplies originating in forested environments.

Forests form the critical source water areas for downstream drinking water supplies in many parts of the world, including the Rocky Mountain regions of North America. Large scale natural disturbances from wildfire and severe insect infestation are more likely because of warming climate and can significantly impact water quality downstream of forested headwaters regions. To investigate potential implications of changing climate and wildfire on drinking water treatment, the 2003 Lost Creek Wildfire in Alberta, Canada was studied. Four years of comprehensive hydrology and water quality data from seven watersheds were evaluated and synthesized to assess the implications of wildfire and post-fire intervention (salvage-logging) on downstream drinking water treatment. The 95th percentile turbidity and DOC remained low in streams draining unburned watersheds (5.1 NTU, 3.8 mg/L), even during periods of potential treatment challenge (e.g., stormflows, spring freshet); in contrast, they were elevated in streams draining burned (15.3 NTU, 4.6 mg/L) and salvage-logged (18.8 NTU, 9.9 mg/L) watersheds. Persistent increases in these parameters and observed increases in other contaminants such as nutrients, heavy metals, and chlorophyll-a in discharge from burned and salvage-logged watersheds present important economic and operational challenges for water treatment; most notably, a potential increased dependence on solids and DOC removal processes. Many traditional source water protection strategies would fail to adequately identify and evaluate many of the significant wildfire- and post-fire management-associated implications to drinking water "treatability"; accordingly, it is proposed that "source water supply and protection strategies" should be developed to consider a suppliers' ability to provide adequate quantities of potable water to meet demand by addressing all aspects of drinking water "supply" (i.e., quantity, timing of availability, and quality) and their relationship to "treatability" in response to land disturbance., (Copyright © 2010 Elsevier Ltd. All rights reserved.)