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Landsat 4-5 Thematic Mapper, Landsat 8 Operational Land Imager, and RapidEye-3 data sets were used to identify potential groundwater discharge zones, via icings, in the Central Mackenzie Valley (CMV) of the Northwest Territories. Given that this area is undergoing active shale oil exploration and climatic changes, identification of groundwater discharge zones is of great importance both for pinpointing potential contaminant transport pathways and for characterizing the hydrologic system. Following the work of Morse and Wolfe (2015), a series of image algorithms were applied to imagery for the entire CMV and for the Bogg Creek watershed (a sub watershed of the CMV) for selected years between 2004 and 2017. Icings were statistically examined for all of the selected years to determine whether a significant difference in their spatial occurrence existed. It was concluded that there was a significant difference in the spatial distribution of icings from year to year ([alpha] = 0.05), but that there were several places where icings were recurring. During the summer of 2018, these recurrent icings, which are expected to be spring sourced, were verified using a thermal camera aboard a helicopter, as well as in situ measurements of hydraulic gradient, groundwater geochemistry, and electroconductivity. Strong agreement was found between the mapped icings and summer field data, making them ideal field monitoring locations. Furthermore, identifying these discharge points remotely is expected to have drastically reduced the field efforts that would have been required to find them in situ. This work demonstrates the value of remote sensing methods for hydrogeological applications, particularly in remote northern locations. Key words: icings, aufeis, permafrost, climate change, groundwater discharge. Des ensembles de données obtenues par capteur Landsat 4-5 Thematic Mapper, imageur Landsat 8 Operational Land Imager et satellite RapidEye 3 ont été utilisés pour cerner d'éventuelles zones d'émergence d'eau souterraine, sous forme d'aufeis, dans la vallée centrale du fleuve Mackenzie (VCFM) des Territoires du Nord-Ouest. Comme cette région est fait l'objet de travaux d'exploration pour le gaz de schiste et subi des changements climatiques, la localisation de zones d'émergence d'eau souterraine revêt une grande importance tant pour l'établissement de possibles voies de transport de contaminants que pour la caractérisation du réseau hydrologique. Comme suite aux travaux de Morse et Wolfe (2015), nous avons appliqué une série d'algorithmes de traitement d'images à l'imagerie pour toute la VCFM et pour le bassin versant du ruisseau Bogg (un sous-bassin de la VCFM) pour des années choisies entre 2004 et 2017. Les aufeis ont fait l'objet d'un examen statistique pour toutes les années sélectionnées afin de vérifier la présence d'une variation significative de leur répartition spatiale. Nous concluons qu'il y avait une variation significative de la répartition spatiale des aufeis d'une année à l'autre ([alpha] = 0,05), mais que des aufeis étaient récurrents en plusieurs endroits. Durant l'été 2018, la présence de ces aufeis récurrents, qui sont présumés être alimentés par des sources, a été validée à l'aide d'une caméra thermique héliportée, ainsi que par des mesures in situ du gradient hydraulique, de la géochimie de l'eau souterraine et de la conductivité électrique. Une bonne concordance a été relevée entre les aufeis cartographiés et les données de terrain estivales, ce qui en fait des sites idéaux pour la surveillance sur place. La détermination par télédétection de ces zones d'émergence aura en outre réduit considérablement les efforts de terrain qui auraient été requis pour les trouver sur place. Ces travaux démontrent l'utilité de méthodes de télédétection pour des applications hydrogéologiques, particulièrement en régions nordiques éloignées. [Traduit par la Rédaction] Mots-clés: aufeis, pergélisol, changement climatique, émergence d'eau souterraine., Introduction The Central Mackenzie Valley (CMV) of the Northwest Territories (NWT), Canada, is a region of active shale oil and gas exploration. In advance of shale oil and (or) gas [...]

Renewable energy transitions are considered key to fuel green transitions. Wind energy is positioned as a cost-beneficial energy source, but also generates environmental conflicts and contestations of distribution of power and benefits. Scalar changes (rescaling) of political, social, and economic structures and processes have gained increased awareness. Less attention has been given to how energy policies influence the scaling of governance regimes, and how energy policies are shaped by changing perceptions and claims. The article explores how and why energy policies rescale governance regimes of wind energy in Norway, Denmark and Scotland. It examines the emergent and relational socio-spatial processes of energy policymaking as assemblages and analyses material and expressive forces influencing wind energy policies and governance scaling/rescaling. The authors find that perceptions of legitimate governance frameworks within energy policy constructions are destabilized/stabilized over time. Scalar shifts within governance frameworks are influenced by forces of market concerns, green growth and value creation, by energy security concerns, stability and industry development, and by concerns of societal welfare, independence, and provision. The authors conclude that divergent forces destabilizing/stabilizing energy policy assemblages and deterritorializing/reterritorializing scalar configurations are influenced by concerns of both energy efficiency and energy justice. [ABSTRACT FROM AUTHOR]

Significant efforts have been expended for improved characterization of hydraulic conductivity (K) and specific storage (Ss) to better understand groundwater flow and contaminant transport processes. Conventional methods including grain size analyses (GSA), permeameter, slug, and pumping tests have been utilized extensively, while Direct Push‐based Hydraulic Profiling Tool (HPT) surveys have been developed to obtain high‐resolution K estimates. Moreover, inverse modeling approaches based on geology‐based zonations, and highly parameterized Hydraulic Tomography (HT) have also been advanced to map spatial variations of K and Ss between and beyond boreholes. While different methods are available, it is unclear which one yields K estimates that are most useful for high resolution predictions of groundwater flow. Therefore, the main objective of this study is to evaluate various K estimates at a highly heterogeneous field site obtained with three categories of characterization techniques including: (1) conventional methods (GSA, permeameter, and slug tests); (2) HPT surveys; and (3) inverse modeling based on geology‐based zonations and highly parameterized approaches. The performance of each approach is first qualitatively analyzed by comparing K estimates to site geology. Then, steady‐state and transient groundwater flow models are employed to quantitatively assess various K estimates by simulating pumping tests not used for parameter estimation. Results reveal that inverse modeling approaches yield the best drawdown predictions under both steady and transient conditions. In contrast, conventional methods and HPT surveys yield biased predictions. Based on our research, it appears that inverse modeling and data fusion are necessary steps in predicting accurate groundwater flow behavior. Article impact statement: Evaluating K from various approaches showed that inverse modeling and data fusion are necessary steps in building robust groundwater models. [ABSTRACT FROM AUTHOR]

A model of the evolution of the onshore wind turbine blade mass installed in Denmark is proposed described by a Weibull distribution, and the age of the blades is estimated from decommissioning data to t50%,onshore = 29 years when half of the blade mass of an installation year has been decommissioned. This is considerably longer than the 20 year design lifetime of onshore turbines, which is often assumed to be an estimate of the End‐of‐Life of turbine blades. Thus, blade waste predictions using the simple assumption may predict that installed blade masses are entering recycling processes about 9 years sooner that what is observed in Denmark. The blade mass for decommissioning in Denmark is estimated to peak at 2000 and 5000 ton/year in 2028 and 2045 using the Weibull model. [ABSTRACT FROM AUTHOR]