Age of Rotational Landslides in the Cypress Hills, Alberta-Saskatchewan

The topography of the west block of the Cypress Hills indicates that fluvial dissection of the plateaux and subsequent rotational landsliding of valley sides have been the dominant Quaternary geomorphic processes. This paper presents a preliminary chronology of rotational landslides based on the relative ages of 17 landslides and on 3 absolute dates. Four indices of relative age were used: organic content in Ah and B soil horizons, the size and coverage of lichens and weathering rind thickness on boulders exposed by landsliding, and the concavity and gradient of gullies in landslide debris, One landslide occurred in 1965. Organic materials collected from buried soil horizons beneath depressions on 3 other landslides were radiocarbon dated at 1235 ± 105, 1635 ± 105 and 7259 ± 165 yrs. BP. Microscopic analysis of the organic material revealed that the oldest sample was contaminated with older carbon. Cluster analysis of the relative age data in conjunction with 3 acceptable absolute dates suggests that the landslides under study have occurred during late Holocene time.La topographie du secteur ouest des Cypress Hills révèle qu'au Quaternaire les principaux processus géomorphologiques ont été l'érosion fluviatile, sur les plateaux, et les glissements de terrain par rotation, sur les versants. Le présent article propose une chronologie des glissements de terrain, 17 ayant une datation relative, et 3, une datation absolue. Quatre indices ont été utilisés pour déterminer l'âge relatif: la teneur en matière organique des horizons pédologiques Ah et B, la concavité et la pente des ravins creusés dans les matériaux, la taille des lichens et Ia surface qu'ils occupent sur des blocs mis au jour par les glissements de terrain, ainsi que l'épaisseur de la couche altérée sur ces blocs. Il y eut un glissement en 1965. À la suite du prélèvement de matière organique dans des horizons pédologiques enfouis, on a pu dater au radiocarbone trois autres glissements (1235 ± 105; 1635 ± 105; 7259 ± 165 BP). L'analyse des échantillons au microscope révèle que Ia matière organique la plus ancienne renfermait du carbone. Une analyse d'ensemble (datations relatives et absolues) laisse penser que les glissements de terrain se sont produits à la fin de l'Holocène.Die Topographie des Westteils der Cypress Hills IaBt erkennen, daB die fluviatile Gliederung der Plateaus und anschlieBende Erdrutsche der Talseiten die wichtigsten geomorphologischen Prozesse im Quaternâr gewesen sind. Dieser Artikel gibt eine vorlâufige Chronologie der Erdrutsche, gestùtzt auf die relative Datierung von 17 Erdrutschen und auf drei absolute Datierungen. Vier Anhaltspunkte wurden fur die relative Datierung benutzt: Der organische Gehalt in den Ah und B Boden-Horizonten, die GrôBe und Ausdehnung der Flechten und die Dicke der Verwitterungskruste auf den durch die Erdrutsche bloBgelegten Blôcken und die Hôhlung und Neigung der Rinnen in den Erdrutsch-Gesteinstrùmmern. Ein Erdrutsch ereignete sich 1965. Organisches Material, das aus vergrabenen Boden-Horizonten unterhalb der Senken von drei anderen Erdrutschen stammt, wurde mit Radiokarbon auf 1235 ± 105, 1635 ± 105 und 7259 ± 165 Jahre BP datiert. Die mikroskopische Analyse des organischen Materials lieB erkennen, daB die àlteste Probe àlteren Kohlenstoff enthielt. Eine Block-Analyse der relativen Datierungen im Zusammenhang mit den drei annehmbaren absoluten Datierungen legt nahe, daB die untersuchten Erdrutsche wâhrend des spâten Holozàn stattgefunden haben

Limitations of Water Resources Infrastructure for Reducing Community Vulnerabilities to Extremes and Uncertainty of Flood and Drought

Debate and deliberation surrounding climate change has shifted from mitigation toward adaptation, with much of the adaptation focus centered on adaptive practices, and infrastructure development. However, there is little research assessing expected impacts, potential benefits, and design challenges that exist for reducing vulnerability to expected climate impacts. The uncertainty of design requirements and associated government policies, and social structures that reflect observed and projected changes in the intensity, duration, and frequency of water-related climate events leaves communities vulnerable to the negative impacts of potential flood and drought. The results of international research into how agricultural infrastructure features in current and planned adaptive capacity of rural communities in Argentina, Canada, and Colombia indicate that extreme hydroclimatic events, as well as climate variability and unpredictability are important for understanding and responding to community vulnerability. The research outcomes clearly identify the need to deliberately plan, coordinate, and implement infrastructures that support community resiliency.Fil: McMartin, Dena W.. University of Regina; CanadáFil: Hernani Merino, Bruno H.. University of Regina; CanadáFil: Bonsal, Barrie. Environment Canada; CanadáFil: Hurlbert, Margot. University of Regina; CanadáFil: Villalba, Ricardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Regional de Investigaciones Cientifícas y Tecnológicas; ArgentinaFil: Ocampo, Olga L.. Universidad Autónoma de Manizales; ColombiaFil: Upegui, Jorge Julián Vélez. Universidad Nacional de Colombia; ColombiaFil: Poveda, Germán. Universidad Nacional de Colombia; ColombiaFil: Sauchyn, David J.. University of Regina; Canad

Future Changes in the Surface Water Balance over Western Canada Using the CanESM5 (CMIP6) Ensemble for the Shared Socioeconomic Pathways 5 Scenario

The Prairie provinces of Canada have about 80% of Canada’s agricultural land and contribute to more than 90% of the nation’s wheat and canola production. A future change in the surface water balance over this region could seriously affect Canada’s agro-economy. In this study, we examined 25 ensemble members of historical (1975 to 2005), near future (2021–2050), far future (2050–2080), and end of the century (2080–2100) simulations of the Canadian Earth System Model version 5 (CanESM5) from the Coupled Model Intercomparison Project Phase 6 (CMIP6). A comprehensive analysis of a new Net Water Balance Index (NWBI) indicates an increased growing season dryness despite increased total precipitation over the Prairie provinces. Evapotranspiration increases by 100–300 mm with a 10–20% increase in moisture loss due to transpiration. Total evaporation decreases by 15–20% as the fractional contribution of evaporation from soil decreases by 20–25%. Total evaporation from vegetation increases by 10–15%. These changes in the surface water balance suggest enhanced plant productivity when soil moisture is sufficient, but evaporative water loss that exceeds precipitation in most years

Future Changes in the Surface Water Balance over Western Canada Using the CanESM5 (CMIP6) Ensemble for the Shared Socioeconomic Pathways 5 Scenario

The Prairie provinces of Canada have about 80% of Canada’s agricultural land and contribute to more than 90% of the nation’s wheat and canola production. A future change in the surface water balance over this region could seriously affect Canada’s agro-economy. In this study, we examined 25 ensemble members of historical (1975 to 2005), near future (2021–2050), far future (2050–2080), and end of the century (2080–2100) simulations of the Canadian Earth System Model version 5 (CanESM5) from the Coupled Model Intercomparison Project Phase 6 (CMIP6). A comprehensive analysis of a new Net Water Balance Index (NWBI) indicates an increased growing season dryness despite increased total precipitation over the Prairie provinces. Evapotranspiration increases by 100–300 mm with a 10–20% increase in moisture loss due to transpiration. Total evaporation decreases by 15–20% as the fractional contribution of evaporation from soil decreases by 20–25%. Total evaporation from vegetation increases by 10–15%. These changes in the surface water balance suggest enhanced plant productivity when soil moisture is sufficient, but evaporative water loss that exceeds precipitation in most years

Ensemble Climate and Streamflow Projections for the Assiniboine River Basin, Canada

The Assiniboine River Basin (ARB) is subject to an exceptionally variable precipitation regime of the Canadian Prairies, ranging between record droughts and unprecedented flooding in just the past decade. To assess the impact of a changing climate on hydroclimate variability in the ARB, we used the bias–corrected simulations from the Canadian Regional Climate Model (CanRCM4) to drive MESH model for two 60–year periods, a historical baseline (1951–2010) and future projection (2041–2100), under the Representative Concentration Pathway (RCP) 8.5 to simulate ARB flows at eight hydrometric stations. The precipitation is projected to increase in every season (~10–38%) except for summer (~−1–−5%). Minimum winter and maximum summer temperatures have the largest seasonal trends, increasing by 2–3 °C in the near future (2021–2050) and 5–6 °C in the far future (2051–2080). These climate changes produce higher winter river flows while peak runoff shifts by several weeks to earlier in the year. There is a shift in the magnitude and timing of extreme water levels. The ensemble of climate projections from a single model and one RCP to the variability and uncertainty in the future hydrology supports adaptation planning in the industrial sectors of Saskatchewan’s economy

Ensemble Projection of Future Climate and Surface Water Supplies in the North Saskatchewan River Basin above Edmonton, Alberta, Canada

Changes in temperature and precipitation are expected to alter the seasonal distribution of surface water supplies in snowmelt-dominated watersheds. A realistic assessment of future climate change and inter-annual variability is required to meet a growing demand for water supplies in all major use sectors. This study focuses on changes in climate and runoff in the North Saskatchewan River Basin (NSRB) above Edmonton, AB, Canada, using the MESH (Modélisation Environnementale communautaire—Surface Hydrology) model. The bias-corrected ensemble of Canadian Regional Climate Model (CanRCM4) data is used to drive MESH for two 60-year time periods, a historical baseline (1951–2010) and future projection (2041–2100), under Representative Concentration Pathway (RCP) 8.5. The precipitation is projected to increase in every season, there is significant trend in spring (0.62) and fall (0.41) and insignificant in summer (0.008). Winter extreme minimum temperature and summer extreme maximum temperature are increasing by 2–3 °C in the near future and 5–6 °C in the far future. Annual runoff increases by 19% compared to base period. The results reveal long-term hydrological variability enabling water resource managers to better prepare for climate change and extreme events to build more resilient systems for future water demand in the NSRB

Climate signals in high elevation tree-rings from the semiarid Andes of north-central Chile: responses to regional and largescale variability

In South America, the arid and semiarid subtropical regions through the Atacama Desert and north-central Chile between 19° and 32°S are currently a gap in the tree-ring chronology network. Only a short tree-ring chronology has been published for this vast region and little is known about the suitability of many woody species for tree-ring analysis and dendroclimatology. In this paper we present the first detailed analysis of the climate responses and influences of the El Niño-Southern Oscillation (ENSO) and the Pacific Decadal Oscillation (PDO) on the tree-rings of three species new to dendrochronology and that typically occur at high elevations in the Andes of central and north-central Chile. Three well-replicated tree-ring chronologies of Kageneckia angustifolia, Proustia cuneifolia and Fabiana imbricata are compared with century-long regional records of precipitation and temperature, and with the N3.4 SST and PDO indices in both time and frequency-domains using correlation and wavelet analysis. The radial growth of these species is controlled by winter precipitation and is also positively correlated with temperature during most of the rainy season from April to September (autumn-spring). The regional climate as well as tree growth is strongly modulated by ENSO and ENSO-like conditions in the equatorial Pacific at both interannual and interdecadal timescales. The decadal and interdecadal variability is not correlated with PDO and appears to be related to the Interdecadal Pacific Oscillation (IPO), a Pacific-wide ENSO-like mode of climate variability. Despite their relatively short lifespans, these three new species have a high potential for dendrochronological and dendroclimatic studies in the semiarid region of Chile over the last two centuries

Re-Evaluating the Climate Factor in Agricultural Land Assessment in a Changing Climate—Saskatchewan, Canada

We established the statistical relationships between seasonal weather variables and average annual wheat yield (Hard Red Spring and Durum wheat: Triticum spp.) for the period of 1979–2016 for 296 rural municipalities (RMs) throughout six soil zones comprising the arable agricultural zone of Saskatchewan, Canada. Controlling climate variables were identified through Pearson’s product moment correlation analysis and used in stepwise regression to predict wheat yields in each RM. This analysis provided predictive regression equations and summary statistics at a fine spatial resolution, explaining up to 75% of the annual variance of wheat yield, in order to re-evaluate the climate factor rating in the arable land productivity model for the Saskatchewan Assessment and Management Agency (SAMA). Historical climate data (1885–2016) and Regional Climate Model (RCM) projections for the growing season (May–August) were also examined to put current climatic trends into longer-term perspective, as well as develop a better understanding of possible future climatic impacts on wheat yield in Saskatchewan. Historical trends demonstrate a decrease in maximum temperature and an increase in minimum temperature and precipitation throughout all soil zones. RCM projections also show a potential increase in temperatures and total precipitation by 5 °C and 10%, respectively. We recommended against a modification of the climate factor rating at this time because (1) any increase in wheat yield could not be attributed directly to the weather variables with the strongest trends, and (2) climate and wheat yield are changing more or less consistently across the zone of arable land, and one soil zone is not becoming more productive than another

Hydrological Extremes in the Canadian Prairies in the Last Decade due to the ENSO Teleconnection—A Comparative Case Study Using WRF

In the Prairie provinces of Alberta, Saskatchewan, and Manitoba, agricultural production depends on winter and spring precipitation. There is large interannual variability related to the teleconnection between the regional hydroclimate and El Niño and La Niña in the Tropical Pacific. A modeling experiment was conducted to simulate climatic and hydrological parameters in the Canadian Prairie region during strong El Niño and La Niña events of the last decade in 2015–2016 and 2010–2011, respectively. The National Center for Atmospheric Research (NCAR) Weather Research and Forecasting (WRF) model was employed to perform two sets of sensitivity experiments with a nested domain at 10 km resolution using the European Centre for Medium-Range Weather Forecasts Reanalysis (ERA) interim data as the lateral boundary forcing. Analysis of the hourly model output provides a detailed simulation of the drier winter, with less soil moisture in the following spring, during the 2015–2016 El Niño and a wet winter during the La Niña of 2010–2011. The high-resolution WRF simulation of these recent weather events agrees well with observations from weather stations and water gauges. Therefore, we were able to take advantage of the WRF model to simulate recent weather with high spatial and temporal resolution and thus study the changes in hydrometeorological parameters across the Prairie during the two extreme hydrological events of the last decade