Rees A.,Knight Piesold Ltd. |
English M.,Wilfrid Laurier University |
Derksen C.,Environment Canada |
Toose P.,Environment Canada |
Silis A.,Environment Canada
Hydrological Processes | Year: 2014
Tundra snow cover is important to monitor as it influences local, regional, and global-scale surface water balance, energy fluxes, as well as ecosystem and permafrost dynamics. Observations are already showing a decrease in spring snow cover duration at high latitudes, but the impact of changing winter season temperature and precipitation on variables such as snow water equivalent (SWE) is less clear. A multi-year project was initiated in 2004 with the objective to quantify tundra snow cover properties over multiple years at a scale appropriate for comparison with satellite passive microwave remote sensing data and regional climate and hydrological models. Data collected over seven late winter field campaigns (2004 to 2010) show the patterns of snow depth and SWE are strongly influenced by terrain characteristics. Despite the spatial heterogeneity of snow cover, several inter-annual consistencies were identified. A regional average density of 0.293 g/cm3 was derived and shown to have little difference with individual site densities when deriving SWE from snow depth measurements. The inter-annual patterns of SWE show that despite variability in meteorological forcing, there were many consistent ratios between the SWE on flat tundra and the SWE on lakes, plateaus, and slopes. A summary of representative inter-annual snow stratigraphy from different terrain categories is also presented. © 2013 John Wiley & Sons, Ltd.
Venier L.A.,Natural Resources Canada |
Dalley K.,Canadian Department of Fisheries and Oceans |
Goulet P.,Canadian Department of Fisheries and Oceans |
Mills S.,Ontario Ministry of Natural Resources |
And 2 more authors.
Forest Ecology and Management | Year: 2015
We compared insular and peninsular residual patches ranging from 0.51. ha to 4.32. ha with plots in dispersed retention and intact forest to evaluate their usefulness to forest birds as habitat in a harvested matrix. We found that forest bird communities were significantly different in all three treatments and that bird communities in patches were an intermediate condition between intact forest and dispersed retention harvest. We observed 12 predominantly forest species, including Brown Creeper (. Certhia americana), Ovenbird (. Seiurus aurocapilla), Yellow-bellied Sapsucker (. Sphyrapicus varius), and Black-throated Blue Warbler (. Setophaga caerulescens), in patches at abundance levels between dispersed retention and intact forest plots. For these species, it appears that patches offer an important habitat in a harvested matrix but at lower abundance than in intact forest. Of the 12 predominantly forest species found in patches, 8 had confirmed breeding. Our results suggest that aggregate retention patches provide breeding quality habitat to a large group of forest species; however, the patches are not equivalent to intact forest suggesting that intact forest should be maintained in landscapes. © 2015 .
Lewsley G.,Knight Piesold Ltd. |
Fannin R.J.,University of British Columbia
Geotechnical Testing Journal | Year: 2011
A new method is described for the reconstitution of cement-treated specimens of sand and silt for laboratory strength tests. Saturation of the slurry mix is attained through boiling the sand fraction at atmospheric pressure, boiling the silt fraction at a pressure that is reduced to a vacuum of 80 kPa, and mechanised blending of cement into the combined soil fractions in a rigid-walled former that is subjected to the same vacuum pressure. Reproducibility of the method is demonstrated from tests on four identical homogeneous specimens that yield a very narrow range in water content, bulk density, and unconfined compression strength. It is further evident in the trend of increasing strength with normalized cement content in those data. Copyright © 1996-2011 ASTM.
Erdas Inc., Leica and Knight Piesold LLC | Date: 1999-05-25
Ford J.D.,McGill University |
Pearce T.,University of Guelph |
Prno J.,Knight Piesold Ltd. |
Duerden F.,Frank Duerden Consulting |
And 3 more authors.
Climatic Change | Year: 2011
A survey documenting how climate change is perceived and responded to by Canadian mine operations was administered to a random sample of practitioners working at mine sites across Canada. Key findings include: (1) Mines are sensitive to climatic hazards; (2) There is concern about climate change among mine practitioners, but the majority have not yet noticed climate change to be affecting operations; (3) Future climate change is expected to have negative impacts for mine operations; (4) Mines are responding to climate change mainly through efforts to reduce greenhouse gas emissions but also through adaptation, although to a lesser degree; and (5) Knowledge of future climate change projections and impacts is limited, potentially constraining understanding of the nature of climate change risks. The survey compliments previous work documenting perceptions among upper level management on climate change in the Canadian mining industry. The results from both surveys are largely consistent, establishing that the mining sector perceives climate change as an emerging risk and is developing response options, but needs to invest more time and resources for adaptation to what are inevitable changes in climate. The results support the need for targeted in-depth research to assess the vulnerability of mining to climate change and to evaluate response options. © 2011 Springer Science+Business Media B.V.