Search

Microlitter is a widespread contaminant with implications for aquatic health; however, knowledge of its distribution in fresh waters is limited. We examined microlitter in surface water, sediment, and mussels within the Saint John River and four major tributaries. Microlitter was present at all 89 sites, with concentrations in water equivalent to other Canadian watersheds. Microlitter concentrations likely reflected differences in land use and development. Comparisons between rivers generally revealed distinct water microlitter particle compositions, suggesting that input sources were specific to each river, while microlitter in sediments and mussels was largely homogeneous among rivers. There was little similarity in concentration and composition of microlitter among the three matrices sampled. Microlitter in sediments and mussels may not reliably track concentration and composition in aquatic environments. Microlitter concentration was not significantly greater downstream of wastewater treatment plants. Airborne microlitter transportation was evident, as remote sites in two tributary rivers demonstrated the highest concentrations of microlitter. Our data highlights the prevalence of microlitter in rural rivers, underscoring the ubiquity of this emerging contaminant and its integration into food webs. [ABSTRACT FROM AUTHOR]

The global change in surface water quality calls for increased preparedness of drinking water utilities. The increasing frequency of extreme climatic events combined with global warming can impact source and treated water characteristics such as temperature and natural organic matter. On the other hand, water saving policies in response to water and energy crisis in some countries can aggravate the situation by increasing the water residence time in the drinking water distribution system (DWDS). This study investigates the individual and combined effect of increased dissolved organic carbon (DOC), increased temperature, and reduced water demand on fate and transport of chlorine and trihalomethanes (THMs) within a full-scale DWDS in Canada. Chlorine and THM prediction models were calibrated with laboratory experiments and implemented in EPANET-MATLAB toolkit for prediction in the DWDS under different combinations of DOC, temperature, and demand. The duration of low chlorine residuals (<0.2 mg/L) and high THM (>80 μg/L) periods within a day in each scenario was reported using a reliability index. Low-reliability zones prone to microbial regrowth or high THM exposure were then delineated geographically on the city DWDS. Results revealed that water demand reduction primarily affects chlorine availability, with less concern for THM formation. The reduction in nodal chlorine reliability was gradual with rising temperature and DOC of the treated water and reducing water demand. Nodal THM reliability remained unchanged until certain thresholds were reached, i.e., temperature >25 °C for waters with DOC <1.52 mg/L, and DOC >2.2 mg/L for waters with temperature = 17 °C. At these critical thresholds, an abrupt network-wide THM exceedance of 80 μg/L occurred. Under higher DOC and temperature levels in future, employing the proposed approach revealed that increasing the applied chlorine dosage (which is a conventional method used to ensure sufficient chlorine coverage) results in elevated exposure toTHMs and is not recommended. This approach aids water utilities in assessing the effectiveness of different intervention measures to solve water quality problems, identify site-specific thresholds leading to major decreases in system reliability, and integrate climate adaptation into water safety management. [Display omitted] • Water demand reduction is more concerning for microbial safety than for THM formation. • Global warming, increased NOM and reduced water demand concurrently threaten water safety. • THM precursors and temperature have a more critical impact on network THMs than water residence time. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Water Resources Journal / Revue Canadienne des Ressources Hydriques is the property of Taylor & Francis Ltd and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The aquarium, water garden, and live seafood trades are major pathways for the introduction of aquatic species into Canada. If released, some imported species may become invasive, with negative consequences for Canadian ecosystems. This research document describes the movement of live aquatic (freshwater, brackish, and marine) organisms including fishes, invertebrates, and plants in trade into and within Canada, identifies aquatic species previously or presently in trade, describes end user participation and the release of aquatic organisms to the wild, develops spatially explicit estimates of propagule pressure, and identifies possible critical control points. A total of 4,296,188 aquarium organisms, representing 844 taxa, were imported into Canada from 40 source countries during a four-month period in 2018. The top three ports of entry, by trade volume, were Windsor, ON; Mirabel, QC; and, Calgary, AB. Imported aquarium organisms were distributed within Canada via major distribution hubs in Innisfil, ON; LaSalle, QC; and, Calgary, AB. Aquarium retailers tended to aggregate around major urban centers. A baseline scenario assuming a 10.6% participation rate and a 3.9% release rate estimated that 57,799 households released 347,650 aquarium organisms per year. During the same four-month timeframe, 3,758,224 water garden organisms, representing 199 taxa, were imported into Canada from 19 source countries. Major ports of entry and distribution hubs for water garden organisms were the same as the aquarium pathway. Water garden retailers were also found around major cities. An estimated 50,769 households released 305,367 water garden organisms per year, based on an assumed 9.2% participation rate and 3.9% release rate. About 82,434,924 live seafood organisms, representing 84 taxa, were imported into Canada from 20 source countries during the same four-month period. Major ports of entry for live seafood organisms included Ottawa, ON; Richmond, BC; St-Stephen, NB; and, Toronto, ON. Montebello, QC; Chilliwack, BC; and, Cap-Pelé, NB were major distribution hubs for live seafood organisms. Similar to the other pathways, live seafood retailers clustered around major cities. An estimated 47,964 users released 288,502 live seafood organisms per year, based on an assumed 3.5% participation rate and 3.9% release rate. Critical control points that allow the greatest volume of organisms in trade to be encountered were identified. For all three pathways, these included the major ports of entry, key distribution hubs, and urban centres where aggregations of retailers, end users, and releasers occur. Results of sensitivity analyses suggested that all parameters considered had an equal effect on the propagule pressure estimates for all pathways, though they had a disproportionate effect on the spatial distribution of end users and releasers. Despite uncertainty around model parameters, statistically significant hot spots of introduction risk were identified. Maintaining detailed import records and characterizing the human dimensions of the aquarium, water garden, and live seafood trades would reduce uncertainty and refine spatially explicit estimates of propagule pressure associated with each pathway. [ABSTRACT FROM AUTHOR]

A snow model forced by temperature and precipitation is used to simulate the spatial distribution of snow water equivalent (SWE) over a 600 000 km2 portion of the province of Quebec, Canada. We propose to improve model simulations by assimilating SWE data from sporadic manual snow surveys with a particle filter. A temporally and spatially correlated perturbation of the meteorological forcing is used to generate the set of particles. The magnitude of the perturbations is fixed objectively. First, the particle filter and direct insertion were both applied on 88 sites for which measured SWE consisted of more or less five values per year over a period of 17 years. The temporal correlation of perturbations enables us to improve the accuracy and the ensemble dispersion of the particle filter, while the spatial correlation leads to a spatial coherence in the particle weights. The spatial estimates of SWE obtained with the particle filter are compared with those obtained through optimal interpolation of the snow survey data, which is the current operational practice in Quebec. Cross-validation results as well as validation against an independent dataset show that the proposed particle filter enables us to improve the spatial distribution of the snow water equivalent compared with optimal interpolation. [ABSTRACT FROM AUTHOR]

Cattle trails in grazed pastures close to rivers may adversely affect surface water quality of the adjacent river by directing runoff to it. The objective of this 3-yr study (2013-2015) in southern Alberta, Canada, was to determine if cattle trails significantly increased the risk of runoff and contaminants (sediment, nutrients) compared with the adjacent grazed pasture (control). A portable rainfall simulator was used to generate artificial rainfall (140 mm h-1) and runoff. The runoff properties measured were time to runoff and initial abstraction (infiltration), total runoff depth and average runoff rates, as well as concentrations and mass loads of sediment, N, and P fractions. Cattle trails significantly (P ≤ 0.10) decreased time to runoff and initial abstraction (26-32%) in the 2 yr measured and increased total runoff depth, runoff coefficients, and average runoff rates (21-51%) in 2 of 3 yr. Concentrations of sediment, N, and P fractions in runoff were not significantly greater for cattle trails than for control areas. However, mass loads of total suspended solids (57-85% increase), NH4-N (31-90%), and dissolved reactive P (DRP) (30-92%) were significantly greater because of increased runoff volumes. Overall, runoff quantity and loads of sediment, NH4-N, and DRP were greater for cattle trails compared with the adjacent grazed pasture, and hydrologic connection with cattle-access sites on the riverbank suggests that this could adversely affect water quality in the adjacent river. Extrapolation of the study results should be tempered by the specific conditions represented by this rainfall simulation study. [ABSTRACT FROM AUTHOR]

The rapid increase in private sector proposals and permit applications to use water for the purpose of hydraulic fracturing has led to significant concerns in nearly every jurisdiction in the world where shale gas development has been explored. In addition to concerns about risks to water quantity and quality, in Canada, shale gas development has highlighted how the Crown (federal and provincial governments) continues to struggle in its approach to honor, respect, and uphold Nation-to-Nation relationships with Indigenous peoples. But moving beyond the criticism, we argue that these circumstances have provided a renewed opportunity to explore alternative governance approaches. Existing water governance challenges are exacerbated by historical injustices generated by resource management approaches that have exposed Indigenous nations to disproportionate environmental risks. Furthermore, the inadequacy of current water governance approaches to recognizing Indigenous rights, self-determination, ways of knowing, and values has been well established in literature relating to environmental governance and Indigenous peoples. Given these circumstances, if water is allocated to hydraulic fracturing in Canada with continued disregard for Indigenous rights and risks, we contend that this only further intensifies unjust environmental and cultural harm to Indigenous peoples. In the quest for solutions, we discuss the challenges to alternative models (co-management, collaborative governance, and impact benefit agreements) that are frequently cited in environment-Indigenous literature. We conclude with recommendations to address the unresolved challenges inherent in these governance models, in the interest of improving water decision-making. WIREs Water 2017, 4:e1180. doi: 10.1002/wat2.1180 For further resources related to this article, please visit the . [ABSTRACT FROM AUTHOR]

Monitoring emerging disinfection byproducts (DBPs) is challenging for many small water distribution networks (SWDNs), and machine learning-based predictive modeling could be an alternative solution. In this study, eleven machine learning techniques, including three multivariate linear regression-based, three regression tree-based, three neural networks-based, and two advanced non-parametric regression techniques, are used to develop models for predicting three emerging DBPs (dichloroacetonitrile, chloropicrin, and trichloropropanone) in SWDNs. Predictors of the models include commonly-measured water quality parameters and two conventional DBP groups. Sampling data of 141 cases were collected from eleven SWDNs in Canada, in which 70 % were randomly selected for model training and the rest were used for validation. The modeling process was reiterated 1000 times for each model. The results show that models developed using advanced regression techniques, including support vector regression and Gaussian process regression, exhibited the best prediction performance. Support vector regression models showed the highest prediction accuracy (R2 = 0.94) and stability for predicting dichloroacetonitrile and trichloropropanone, and Gaussian process regression models are optimal for predicting chloropicrin (R2 = 0.92). The difference is likely due to the much lower concentrations of chloropicrin than dichloroacetonitrile and trichloropropanone. Advanced non-parametric regression techniques, characterized by a probabilistic nature, were identified as most suitable for developing the predictive models, followed by neural network-based (e.g., generalized regression neural network), regression tree-based (e.g., random forest), and multivariate linear regression-based techniques. This study identifies promising machine learning techniques among many commonly-used alternatives for monitoring emerging DBPs in SWDNs under data constraints. [Display omitted] • Eleven machine learning techniques were compared for predicting emerging DBPs. • Support vector regression and Gaussian process regression are best-performing. • Support vector regression reduced 90 % error compared to linear regression. • Gaussian process regression reduced 67 % error compared to linear regression. • The two advanced regression techniques also showed the lowest prediction variance. [ABSTRACT FROM AUTHOR]

The water distribution system hydraulic model for an Ontario, Canada town has been calibrated by engineers familiar with the system. Their calibration procedure was mainly an expert-based approach using judgment and trial-and-error and did not rely on optimization. The purpose of this study is to resolve the corresponding calibration problem with optimization tools and compare the calibration solutions in terms of quality (closeness to measured data) and calibration parameter values. The calibration problem is posed as a multi-objective optimization problem and solved with the PA-DDS algorithm described in [1]. The precise calibration objectives are roughly matched to the manual calibration objectives specified by the engineers who calibrated the model. Multi-objective optimization results are compared with the current solution to determine if the current solution is non-dominated. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Water Resources Journal / Revue Canadienne des Ressources Hydriques is the property of Taylor & Francis Ltd and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A large-scale pump performance and efficiency testing program was conducted across the province of Ontario (Canada) involving testing more than 150 water pumps in eight municipal water supply and distribution systems. The program's objectives included raising awareness of the state of pump energy efficiencies and opportunities for energy conservation, as well as the development of a benchmarking report which can be used as a key reference by water utilities in their efforts to improve the energy efficiency of their pumping systems. This is the first program of its kind in Canada and seeks to establish an understanding of the performance and efficiency of water pumps in the field using state-of-the-art thermodynamic technology. The generalized results of this program indicate that the average efficiency of the pumps tested is 9.3% lower efficiency than the manufacturer's original claims at the best efficiency point, while the average gap between the manufacturer's original best efficiency point and actual point of operation in the field was 12.7%. [ABSTRACT FROM AUTHOR]

• A novel hybrid deep-learning-based recurrent model was proposed to map water clarity. • A clear global pattern of temporal and spatial changes in water clarity was revealed. • Water depth most determined the global spatial distribution pattern of water clarity. • Water clarity of most global lakes between 2014 and 2020 remained stable. • Water clarity in COVID-19 period showed a significant increase in most global lakes. Information regarding water clarity at large spatiotemporal scales is critical for understanding comprehensive changes in the water quality and status of ecosystems. Previous studies have suggested that satellite observation is an effective means of obtaining such information. However, a reliable model for accurately mapping the water clarity of global lakes (reservoirs) is still lacking due to the high optical complexity of lake waters. In this study, by using gated recurrent units (GRU) layers instead of full-connected layers from Artificial Neural Networks (ANNs) to capture the efficient sequence information of in-situ datasets, we propose a novel and transferrable hybrid deep-learning-based recurrent model (DGRN) to map the water clarity of global lakes with Landsat 8 Operational Land Imager (OLI) images. We trained and further validated the model using 1260 pairs of in-situ measured water clarity and surface reflectance of Landsat 8 OLI images with Google Earth Engine. The model was subsequently utilized to construct the global pattern of temporal and spatial changes in water clarity (lake area>10 km2) from 2014 to 2020. The results show that the model can estimate water clarity with good performance (R2 = 0.84, MAE = 0.55, RMSE = 0.83, MAPE = 45.13%). The multi-year average of water clarity for global lakes (16,475 lakes) ranged from 0.0004 to 9.51 m, with an average value of 1.88 ± 1.24 m. Compared to the lake area, elevation, discharge, residence time, and the ratio of area to depth, water depth was the most important factor that determined the global spatial distribution pattern of water clarity. Water clarity of 15,840 global lakes between 2014 and 2020 remained stable (P ≥ 0.05); while there was a significant increase in 243 lakes (P < 0.05) and a decrease in 392 lakes (P < 0.05). However, water clarity in 2020 (COVID-19 period) showed a significant increase in most global lakes, especially in China and Canada, suggesting that the worldwide lockdown strategy due to COVID-19 might have improved water quality, espically water clarity, dueto the apparent reduction of anthropogenic activities. [Display omitted] [ABSTRACT FROM AUTHOR]

The ability to regularly deliver safe drinking water is a constant challenge to municipalities worldwide. In Canada, the replacement/rehabilitation cost of water mains is estimated to be $28 billion (1997–2012). Therefore, selecting cost-effective repair and/or rehabilitation scenario(s) is essential to optimise the quality of existing water mains and minimise unnecessary rehabilitation costs. The research presented in this paper identifies several rehabilitation methods for water mains, which are classified into three main categories: (1) repair (i.e. open trench, sleeves); (2) renovation (i.e. slip lining, cement mortar lining, epoxy lining, cured in place pipe (CIPP)); and (3) replacement (i.e. pipe bursting, micro-tunnelling, horizontal directional drilling, auger boring, open cut). Due to complexity, scarcity, and enormity of data required to perform life cycle cost (LCC) and select the cost-effective scenario(s), the research presented focuses on LCC data acquisition and analysis. Data were collected from contractors and municipalities in Canada. Rehabilitation decision trees were developed as a preparation step for future LCC implementation. Breakage rate analysis was successfully developed to predict the intervals of various rehabilitation alternatives. The research presented is relevant to researchers and practitioners (municipal engineers, consultants, and contractors) to prioritise pipe inspection and rehabilitation planning for existing water mains. [ABSTRACT FROM AUTHOR]

The article cites a basic survey conducted by the Utah State University which notes the water utilities across the U.S. and Canada to ensure the main failures of water supply systems in both countries. It mentions the primary goal of the survey is to create an inventories and rates of different pipe materials. It also notes on the common reasons for water failure mode which are identified as to circumferential cracks, corrosion and longitudinal cracks.

The objective of this paper is to assess the impact of proposed Canadian climate change mitigation policies (discounting and carbon pricing) on cost, energy use, and greenhouse gas (GHG) emissions in the single-objective design/expansion optimization of the Amherstview water distribution system in Amherstview, Ontario, Canada. The single-objective optimization problem is solved with the elitist genetic algorithm (EGA). The optimization approach is used in a parametric analysis to examine the impact of discounting and carbon pricing on GHG reductions for cement-mortar ductile iron and polyvinyl chloride pipe materials. Preliminary results indicate that the discount rate and carbon prices investigated had no significant influence on energy use and GHG mass in the Amherstview system and did not meet the emission-reduction targets set by the Canadian government. This result was attributed to a number of factors, including adequately installed hydraulic capacity in the Amherstview system, the use of a time-declining GHG emission intensity factor, and the scope of the expansion problem. [ABSTRACT FROM AUTHOR]

Abstract: Recently enacted regulations in Canada and elsewhere require water utilities to be financially self-sustaining over the long-term. This implies full cost recovery for providing water and wastewater services to users. This study proposes a new approach to help water utilities plan to meet the requirements of the new regulations. A causal loop diagram is developed for a financially self-sustaining water utility which frames water and wastewater network management as a complex system with multiple interconnections and feedback loops. The novel System Dynamics approach is used to develop a demonstration model for water and wastewater network management. This is the first known application of System Dynamics to water and wastewater network management. The network simulated is that of a typical Canadian water utility that has under invested in maintenance. Model results show that with no proactive rehabilitation strategy the utility will need to substantially increase its user fees to achieve financial sustainability. This increase is further exacerbated when price elasticity of water demand is considered. When the utility pursues proactive rehabilitation, financial sustainability is achieved with lower user fees. Having demonstrated the significance of feedback loops for financial management of water and wastewater networks, the paper makes the case for a more complete utility model that considers the complexity of the system by incorporating all feedback loops. [Copyright &y& Elsevier]

Cedric Masey White is a notable British hydraulician of the twentieth century, having particularly contributed to the pipe flow problem in collaboration with his PhD student Cyril Frank Colebrook. Their solution is currently accepted universally, although some particular questions remain as yet unresolved. This biographical work further introduces the professional background of White during his stays at King's College and Imperial College, London, where he became one of the most renowned British hydraulicians mainly because he introduced the post graduate course in hydraulics after World War II. This work also describes how the author was able to find White's daughter in Canada, and how she kindly gave her support in terms of photographs and biographical details. A well-known figure in the field of hydraulics is therefore finally given acknowledgement by an adequate biography. [ABSTRACT FROM AUTHOR]

This paper presents a methodology that can effectively identify contributions of water sources to end-use water consumption in distribution network locations. The sector selected for the study is a residential sector of Quebec City supplied with drinking water directly from the main supply pipes from the water treatment plant and by re-chlorinated water from a reservoir. The proposed methodology relies on three strategies: a hydraulic characterization of the distribution network, a tracer study and a water quality characterization study. A tracer study was conducted by injecting CaCl2 brine at the reservoir outlet in order to increase calcium concentrations in water from that source. It was then possible to associate sampling points at which calcium concentrations showed an increase during the test as being supplied by the reservoir. A water quality characterization study was conducted simultaneously with the tracer study, making it possible to validate the distribution zones identified. This validation was made possible by analysing the difference between residual chlorine values from the two sources; in fact, water from the reservoir had distinctively higher levels due to re-chlorination. With this fact, it was possible to identify distribution zones at points where the calcium concentration had remained constant during the tracer test. [ABSTRACT FROM AUTHOR]

Annual break rates are often used by municipalities as one of the most important criteria in rating the condition of water mains. This paper presents the development of deterioration models that predict the annual break rates of water mains considering pipe material, diameter, age, and length. The data used in this paper are collected from a Canadian municipality that has a large water distribution network. The collected data cover 15-year pipe break records of 432 km of water mains. Five multiple regression models are developed, which show robust statistical analysis. Twenty percent of break data were randomly selected for validation in which the developed models demonstrate satisfactory results. The research presented in this paper is expected to be useful to academics and practitioners (municipal engineers, consultants, and contractors) in analyzing deterioration trends of water mains. [ABSTRACT FROM AUTHOR]

Water is needed for oil sand developments in the lower Athabasca River basin of northern Alberta, Canada, and is also a key consideration from an ecological and fish habitat perspective, particularly in winter when river flows are at their lowest. Efforts to establish an appropriate flow management regime for the lower Athabasca included revision of River2D, a fixed bed, depth-averaged finite element model, available from www.river2d.ca, to predict hydraulics with a partial or total ice cover. Hydrometric surveys from three reaches of the Athabasca River were used to test the model, assess different model calibration methods, and simulate hydrodynamics for ice-covered conditions. Calibrating bed roughness from ice-free data, assuming the same bed roughness for ice-covered conditions, or the reverse, provided a close fit to the surveyed water surface elevations. The applied ice and composite roughness heights differed according to the applied method of calibration. This may have implications for local velocity estimates possibly affecting fish habitat suitability. A range of bed and composite grain roughness heights, corresponding to different bed substrates and ratios of bed and composite roughness heights to water depths, are provided for model calibration purposes. [ABSTRACT FROM AUTHOR]

Data regarding water main breaks are widely considered important for effective water distribution asset management. This article presents the results of a survey administered to small and medium-sized utilities to evaluate the state of data collection practices for water main breaks in the United States and Canada. The survey included questions about the amount and type of data collected by water utilities, the utilities' level of comfort with the amount of data collected, and the availability of data elsewhere within the utility. The survey results show that the amount of data collected can be classified by the degree of data richness and defined as either an expanded, intermediate, limited, or minimal data set. Analysis of the results suggests that utilities can implement practices to increase the amount of data they collect and increase the effectiveness of their data collection and processing. The results also suggest that utilities can improve their data sets by considering additional sources of data for water main breaks. INSET: Statistical analysis of the survey sample. [ABSTRACT FROM AUTHOR]

Saturated hydraulic conductivity (Ks) is an important soil hydraulic property that affects water flow and the transport of dissolved solutes. Obtaining sufficient and reliable Ks data for large-scale process modeling is always a challenge due to the extremely high spatial variability. The objectives of this study were (i) to determine if a monofractal or multifractal approach is needed to describe the variability in Ks and its soil surrogates, and (ii) to identify which soil property best reflects the spatial distribution of Ks across a wider range of scales. Saturated hydraulic conductivity and soil physical property data were collected from a 384-m transect, located at Smeaton, 5K, Canada. Observation scale variability and relationships were examined using statistical and geostatistical methods. Statistical scale-invariance was evaluated through the Hurst scaling parameter (H). Multiple scale variability and relationships were studied using multifractal and joint multifractal techniques. Results indicate that for all the studied vari- ables 0.80 < H < 0.90, suggesting a certain degree of statistical scale-invariance and long-range dependency. At the observation scale, the variability in Ks was significantly related to sand (SA) and silt (SI) distribution (R = 0.40 for SA and -0.39 for SI, P < 0.01; n = 128), whereas, across a wider range of scales, the variability in Ks was related only to clay (CL) and organic C (OC). The result indicates scale dependent relationships between Ks and soil physical properties, which implies that the success of predictive models such as pedotransfer functions (PTFs) and Ks aggregation techniques depends largely on the correspondence between observation and implementation scales. [ABSTRACT FROM AUTHOR]

Provides examples on how water utilities in Canada, the U.S. and Australia are using geographic information systems (GIS) to manage and maintain their water distribution networks. Advantages of using GIS; Information on how GIS can be used to analyze the data collected during a water main corrosion study; Relationship between soil properties and the external corrosion of cast-iron water mains.

Evaluates the soil properties responsible for the external corrosion of cast iron mains in Toronto, Ontario. Description of the city's water distribution network; Processes associated with corrosion; Classification of soil samples.

• Water potentials are higher in the east and west coasts. • Most severe low flow conditions were in the Prairies and norther territories. • Spring snowmelt is a trigger of high flows in most provinces. • Atlantic provinces, Ontario, and Quebec showed a second high flow period in autumn. • Flatter flow duration curves are observed in rivers with larger water potentials. Water resources play an important role in many aspects of our daily lives, e.g. industrial food processing, irrigation, and hydropower generation, etc. The natural flow regime and water availability were studied across Canada using 167 catchments from the Water Survey of Canada dataset (Reference Hydrometric Basin Network - RHBN). We established a systematic analysis of water availability (annual and monthly runoff) to determine both the quantity and distribution of water within the year. In each province, we investigated the severity of low flow conditions namely the magnitude, seasonality, and duration of extreme low flows. There are prominent disparities in water availability at the annual and monthly time scales across Canada. The annual runoff characteristics showed a relatively abundant quantities of water on the east and west coasts (800-2300 mm/year). Annual runoff is critically low (<150 mm/year) in the prairies and northern territories. Monthly analyses revealed eminent differences in the timing and magnitude of high and low flows. The spring snowmelt is the main trigger of high flows in most provinces. However, the quantities of water during freshet period varied dramatically across provinces. British Columbia showed among the highest hydrological variability where some catchments showed relatively high flows year around. In Canada, a second high flow period was observed in some provinces (e.g., Quebec, Ontario, and the Maritimes). The underpinning hydrological processes and the precipitation regime are discussed to explain the regional hydrologic disparities. The monthly flow of the 80th percentile (Q 80 ; monthly flow duration curve) was used as the cutoff to describe low flows both in terms of magnitude and duration. The Q 80 variability across Canadian rivers was significantly large (0.3-100 mm/month). Many regions have one period of extreme low flows except in Newfoundland, New Brunswick, British Columbia, Ontario, Quebec and Saskatchewan where 2 seasons of low flows can be observed. In Newfoundland and New Brunswick the low flow period was the shortest (2.6 months). In contrast, in the prairies and north territories, the low flow period extended between 3.4 and 4 months. We further explained the disparities in water availability and low flows from analysis of the daily flow duration curve (FDC). We quantified the differences in the flow response from flow indices calculated from FDC (baseflow index, low flow index, and slope of the FDC). The results of water availability and low flows have important socio-economic impacts on water supply, reservoir operations, and far-reaching implications on the health of aquatic habitats. [ABSTRACT FROM AUTHOR]

The city of Hamilton's water distribution system is one of Canada's oldest and most complex water distribution systems. Situated at the west end of Lake Ontario, the city has an elevation of 298 ft (91 m) above sea level and is defined by unique geographical features, including the Niagara Escarpment and the Hamilton Harbor. [ABSTRACT FROM AUTHOR]

Regionalization is of great practical importance, being applied in fields ranging from air space to water distribution. Canada has one of the highest waste generation rates in the world, disposing an average of 694.4 kg/cap in 2018. Waste management costed Canadians about CAD $3.3 billion in 2016, with collection and transportation making up 41.3% of this expenditure. Regionalized waste management systems are becoming popular in Canada and around the world; and design and optimization of regions is vital. Different spatial statistics are used to optimize 3 sub-regions in Saskatchewan (Regina, Leinan, and Beatty). Centroidal Voronoi Tessellation is generally the most efficient method. When the ratio of populated places to road length is low (0.010), 'median center' better optimized populated places in each sub-region. Computational demand was highest in Beatty (19.0 iterations), followed by Regina (9.67 iterations) and Leinan (5.33 iterations) indicating a trade-off between the number of sub-regions, computational efficiency, and optimized percent standard deviation. A strong linear relationship is observed in some cases between percent SD of optimized parameters and standard deviation of area, indicating the importance of relative size in optimization. In Regina, Median center (rank = 2) was ranked higher than mean center (rank = 3), while the opposite was true in Beatty. Feature distribution within regions and different spatial statistics in the algorithm should be explored. This work is of practical importance in waste management and other fields where region development is important. [ABSTRACT FROM AUTHOR]

In Nova Scotia the threatened Northern Ribbonsnake, Thamnophis sauritus septentrionalis, (the northern subspecies of the Eastern Ribbonsnake, T. sauritus) (Crother 2008) is known from localities in only Queens and Lunenburg counties, where it was first discovered in 1950. Many new localities, mostly in the headwaters of the Mersey River and the Medway River watersheds have been added since 2002, and Seven Mile Lake (in the West La Have River watershed) was added to the distribution in 2005. We add two localities to the distribution of the Northern Ribbonsnake in the previously unreported Petite Rivière watershed, Lunenburg County, Nova Scotia. [ABSTRACT FROM AUTHOR]