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This paper provides an outlook on the effects of climate change and the severity and frequency of extreme weather events on the performance of flexible pavements across North America. Now more than ever, the climate is changing at a rapid pace, which will alter long-term environmental loading parameters and extreme weather events. Such alterations will pose implications for the design, maintenance, and rehabilitation of flexible pavements, especially in terms of their serviceability, safety, and functionality. In northern Canada, roads are founded on various terrain types, including thaw-sensitive ice-rich permafrost underlying terrains. Such roads have experienced signs of embankment and pavement damage, which are usually induced by the degradation of the underlying permafrost due to climate change. Therefore, the development and implementation of new permafrost thaw mitigation techniques for vulnerable roads are essential and will be discussed in this paper. Resilient flexible roads should be designed to withstand the conditions that are likely to occur during their design life, taking into account the impact of the climate change on pavement performance in response to daily and seasonal changes in heat, precipitation, freeze–thaw cycles, and extreme weather events. [ABSTRACT FROM AUTHOR]

Climate change will have a significant impact on the hydrological cycle. This paper presents the results of a pilot project for the Yamaska River in Québec. The objective of this project is to evaluate the river's vulnerability to low flows attributable to climate change and to analyze a no-regrets adaptation strategy at locations identified as vulnerable. The vulnerability was evaluated using statistical indicators (low flow indices) based on long-term observations at four locations in the basin. A distributed physically-based hydrological model in use in Québec was calibrated and validated against observed streamflow data to properly represent low flows. Hydrological simulations used seven climate projections provided by the north american regional climate change assessment program (NARCCAP) s project. Also, five members of the canadian regional climate model (CRCM), nested with the coupled global climate model (CGCM) under the special report on emission scenarios (SRES) A2 emission scenario, were run for a reference (1971-2000) period and a future (2041-2070) period. Streamflow simulations indicate a degradation of future low flow conditions, particularly in June and August, when compared to the reference period. In addition, the 7-day low flow value with a 2-year return period (7Q2) and the 7-day low flow value with a 10-year return period (7Q10) decrease by 16-64% and 18-45% respectively. A no-regrets adaptation strategy allowing stakeholders to reduce withdrawal according to alert levels was implemented. Simulations of the application of the no-regrets adaptation strategy reduced the number of days where streamflows are below the Crisis level in the future period by at least 20%. [ABSTRACT FROM AUTHOR]

Climate change is expected to alter the frequency and intensity of extreme rainfall events, affecting the rainfall intensity-durationfrequency (IDF) curve information used in the design, maintenance, and operation of water infrastructure in Canada. Presented in this study are analyses of precipitation data from 567 Environment Canada hydro-meteorological stations using the web-based IDF_CC tool, which applies a novel equidistance quantile-matching downscaling method to generate future IDF curve information. Results for the year 2100 based on The Second Generation Canadian Earth System Model (CanESM2) and a multimodel ensemble median of 24 global climate models (GCMs) were generated. A natural neighbor spatial interpolation method was used to generate results for ungauged locations. One in 5-year, 2-h and one in 100-year, 24-h precipitation events were explored. Results based on CanESM2 indicated a reduction in extreme precipitation in central regions of Canada under specific analyses and increases in other regions. Relative to the multimodel ensemble median approach, the CanESM2 results suggested more spatial variability in change of IDFs, and the ensemble median generated generally lower values than CanESM2. By using the median value that lowers the importance of extreme outputs, the ensemble median approach obscured uncertainty associated with GCM outputs. While the IDF_CC tool helps fill an important gap related to accessing local climate change information, it is important to consider uncertainty in GCM outputs when making climate change adaptation decisions. [ABSTRACT FROM AUTHOR]

Modern structural design codes assume a statistically stationary climate. However, it is now known that the climate is changing at a rate that calls into question the stationarity assumption. This study was undertaken to explore various methods of accounting for climate nonstationarity. The geographical domain of this study covers most of Canada, intending to explore how best to update future climatic variables in the National Building Code of Canada (NBC). Outputs from future climate simulations for North America by Environment and Climate Change Canada (ECCC) and the Pacific Climate Impacts Consortium (PCIC) were used, focusing on a representative concentration pathway (RCP) scenario, namely the RCP8.5 emissions scenario. Surface hourly mean wind speeds and ground snow amounts were extracted from the simulations and used to detect and quantify trends in the extreme climatic variables from 1950 through 2100. This study reviewed different concepts for evaluating climatic design variables under stationary and nonstationary climates. It was found that within the range of linear nonstationarity detected for grid points within Canada, the results predicted using these nonstationary methods are close. Therefore, a simpler approach, namely Minimax design life level, was adopted to estimate the design wind speeds for 1/50 and 1/500 annual probability of exceedance and the design ground snow loads for 1/50 and 1/1,000 annual probability of exceedance. Design values derived based on nonstationary approaches were compared with the results estimated using the conventional return period concept between 1986 and 2016 and a moving-time-window method between 2060 and 2090 centered at 2075. [ABSTRACT FROM AUTHOR]

Barge transport operations on the Mackenzie River, a major transportation corridor in the Northwest Territories, are impacted by multiple sources of uncertainties. In particular, the impacts of climate change on this important corridor have led to summer shipping seasons that are growing more volatile in terms of length and quality. This change can lead to a growing reliance on costly airlifts for delivering essential freight that cannot be delivered by barge during seasons that end early due to low water. The Government of Northwest Territories has been planning the construction of the Mackenzie Valley Highway (MVH) for decades to provide cheaper, more reliable transportation for communities. However, the costs of constructing the MVH are prohibitive, and traditional benefit-cost analyses are unable to consider flexible investment actions in response to uncertainties. Therefore, we apply a real options modeling framework to determine if and when to construct the different segments of the MVH, considering climate change and freight demand uncertainties. We first model climate and freight demand uncertainties as geometric Brownian motion processes. Next, a benefit-cost model is developed. Finally, we use the least-squares Monte Carlo method to solve for extended project values and optimal investment times for each segment. The results indicate that Segment 2 has the largest value with an optimal seven-year delay in investment time, followed by Segment 1, Segment 3, and Segment 4 in the last year of the planning period (or possibly beyond). Freight demand volatility appears to have the greatest impact on project values and investment years. The results show that, although the benefits of construction may not outweigh the costs now, they may at some future date; in between, decision makers have opportunities to change their minds as conditions change. This is particularly important in northern Canada, where highly costly infrastructure investment decisions are subject to massive uncertainties. Overall, we see such an approach as a tool to communicate the value of uncertainty in infrastructure benefit-cost analyses and as one tool in a larger decision-support toolbox that is required for major transportation investments in northern Canada. [ABSTRACT FROM AUTHOR]