•DEMO is a flexible method that can include additional objective functions.•Accounting for recharge increases spatial coverage of monitoring network.•Interpolation methods influence monitoring well ...placements in networks.
This study explores the inclusion of a groundwater recharge based design objective and the impact it has on the design of optimum groundwater monitoring networks. The study was conducted in the Hamilton, Halton, and Credit Valley regions of Ontario, Canada, in which the existing Ontario Provincial Groundwater Monitoring Network was augmented with additional monitoring wells. The Dual Entropy-Multiobjective Optimization (DEMO) model was used in these analyses. The value of using this design objective is rooted in the information contained within the estimated recharge. Recharge requires knowledge of climate, geomorphology, and geology of the area, thus using this objective function can help account for these physical characteristics. Two sources of groundwater recharge data were examined and compared, the first was calculated using the Precipitation-Runoff Modeling System (PRMS), and the second was an aggregation of recharge found using both the PRMS and Hydrological Simulation Program-Fortran (HSP-F). The entropy functions are used to identify optimal trade-offs between the maximum information content and the minimum shared information between the monitoring wells. The recharge objective will help to quantify hydrological characteristics of the vadose zone, and thus provide more information to the optimization algorithm. Results show that by including recharge as a design objective, the spatial coverage of the monitoring network can be improved. The study also highlights the flexibility of DEMO and its ability to incorporate additional design objectives such as the groundwater recharge.
Hamilton, Ontario, like many cities heavily dependent on manufacturing in the 20th century, experienced de-industrialization and associated change in its economic and employment fortunes, as well as ...comparative weakened fiscal strength. In contrast to cities in the United States though, Hamilton's population kept growing, at least slowly, and its unemployment rate never skyrocketed, even though the proportion of the population earning middle- to high-incomes declined for a time. In urban scholarship, dramatic population loss has attracted researchers to study shrinking cities, however population change fails to tell the entire story of the possible fates of rust-belt cities that also requires the analysis of economic changes. Our aim is to identify Hamilton's challenges and characteristics followed by how current political, financial and regional circumstances shape the city's development and create different circumstances for post-industrial cities. We review this using Hamilton's census data since 1951 and fiscal data, development projects, and interviews with local public officials and private business reveals the significant impact the post-industrial era and the Canadian perspective. Our findings suggest that despite differences between shrinking characteristics in Canadian and US cities, Canadian cities should receive more attention and offer a different perspective on the “rust-belt” literature.
•This paper investigates Hamilton, Ontario and the US typology of post-industrial cities.•Population increases disguise other issues prominent in shrinking cities.•Hamilton's economy indicates the severity of post-industrial economic changes.•Investing in cultural events and sport has shown some evidence of downtown revitalization.•Differing declining cities strengthens the significance of place based characteristics.
Key Takeaways
The City of Hamilton, Ontario, developed a corrosion control program after discovering over 10% of residential plumbing samples had lead concentrations exceeding the maximum allowable ...concentration of 10 μg/L.
Preliminary studies suggested that the best corrosion control method for the city was a phosphate‐based inhibitor that would protect Hamilton customers from all contact sources of lead in drinking water.
Multiple public outreach and educational campaigns informed the public of the city's efforts and contributed to the success of its program.
The Niagara Escarpment is a fractured Palaeozoic sedimentary cuesta, subject to year-round weathering in a temperate climate. We examined the temperature of the rock surface and fractures at three in ...situ sites with varying aspect and lithology, as well as the surface and interior of three control blocks maintained in outdoor conditions between December 2020 and March 2021. The objectives were to examine the interplay between freeze–thaw and thermal weathering in the winter months and to identify potential factors influencing these processes. Both diurnal-scale and prolonged freeze–thaw cycles differing in spatial and temporal extent were identified, coincident with periods of high moisture. We frequently observed rapid temperature changes (>1 °C min−1) at sites with strong insolation, which implies that the temperature regime is suitable for thermal shock and fatigue to occur. Site-specific factors, such as the aspect of the escarpment face and lithology, impact the mechanism and extent of weathering. Southeast-facing sites with high insolation are dominated by diurnal-scale freeze–thaw; west- and east-facing sites with lower insolation experience a more prominent prolonged freeze–thaw cycle. Across all sites there is a gradient between surface and fracture temperature that follows diurnal trends in air temperature and insolation. Variability in the surface-fracture gradient may enhance weathering processes by shifting the orientation and magnitude of stress, and by changing the spatial distribution of freezing and thawing. Our research indicates that site-specific factors and pre-existing fractures moderate the influence of air temperature and insolation on thermal gradients, and ultimately the weathering regime.
Solitary rugose corals assigned to Streptelasma rutkae n. sp. and an annulated orthoconic cephalopod identified as Gorbyoceras sp. occur in nearshore shallow-marine sandstone of the Whirlpool ...Formation in Hamilton, southern Ontario. They are the first macrofossils contributing to a modern understanding of the age and correlation of this stratigraphic unit. Streptelasma rutkae most closely resembles S. subregulare (Savage, 1913), which occurs widely in the Edgewood Province of the east-central United States, in strata considered latest Ordovician (Hirnantian). Gorbyoceras ranges into the latest Katian (latest Richmondian) in the Cincinnati Arch region. Thus, the occurrences of S. rutkae and Gorbyoceras sp. support other biostratigraphic and chemostratigraphic data suggesting that the Whirlpool Formation is latest Ordovician, rather than earliest Silurian as traditionally thought. They also indicate paleogeographic connections between the area of Whirlpool deposition in Ontario and the Edgewood Province and Cincinnati Arch region in the east-central United States UUID: http://zoobank.org/d1ded814-204d-4070-a469-52d3b6e259c7
Adequate and accurate hydrologic information from optimal hydrometric networks is an essential part of effective water resources management. Although the key hydrologic processes in the water cycle ...are interconnected, hydrometric networks (e.g., streamflow, precipitation, groundwater level) have been routinely designed individually. A decision support framework is proposed for integrated design of multivariable hydrometric networks. The proposed method is applied to design optimal precipitation and streamflow networks simultaneously. The epsilon‐dominance hierarchical Bayesian optimization algorithm was combined with Shannon entropy of information theory to design and evaluate hydrometric networks. Specifically, the joint entropy from the combined networks was maximized to provide the most information, and the total correlation was minimized to reduce redundant information. To further optimize the efficiency between the networks, they were designed by maximizing the conditional entropy of the streamflow network given the information of the precipitation network. Compared to the traditional individual variable design approach, the integrated multivariable design method was able to determine more efficient optimal networks by avoiding the redundant stations. Additionally, four quantization cases were compared to evaluate their effects on the entropy calculations and the determination of the optimal networks. The evaluation results indicate that the quantization methods should be selected after careful consideration for each design problem since the station rankings and the optimal networks can change accordingly.
Key Points
A decision support system for integrated hydrometric networks design and evaluation was developed
Entropy measures and multiobjective optimization were combined to find optimal networks simultaneously for multiple hydrologic variables
Four quantization cases for calculating discrete entropy and their effects on the network design were also evaluated
Data assimilation (DA) has been widely used in hydrological models to improve model state and subsequent streamflow estimates. However, for poor or non-existent state observations, the state ...estimation in hydrological DA can be problematic, leading to inaccurate streamflow updates. This study evaluates the soil moisture and flow variations and forecasts by assimilating streamflow and soil moisture. Three approaches of Ensemble Kalman Filter (EnKF) with dual state-parameter estimation are applied: (1) streamflow assimilation, (2) soil moistue assimilation, and (3) combined assimilation of soil moisture and streamflow. The assimilation approaches are evaluated using the Sacramento Soil Moisture Accounting (SAC-SMA) model in the Spencer Creek catchment in southern Ontario, Canada. The results show that there are significant differences in soil moisture variations and streamflow estimates when the three assimilation approaches were applied. In the streamflow assimilation, soil moisture states were markedly distorted, particularly soil moisture of lower soil layer; whereas, in the soil moisture assimilation, streamflow estimates are inaccurate. The combined assimilation of streamflow and soil moisture provides more accurate forecasts of both soil moisture and streamflow, particularly for shorter lead times. The combined approach has the flexibility to account for model adjustment through the time variation of parameters together with state variables when soil moisture and streamflow observations are integrated into the assimilation procedure. This evaluation is important for the application of DA methods to simultaneously estimate soil moisture states and watershed response and forecasts.
The Niagara Escarpment is a geological feature located in southern Ontario, Canada, and the northeastern United States, comprising highly fractured sandstone, shale and carbonates deposited during ...the Ordovician and Silurian periods. Differential erosion of the strata has generated a steep cliff face which bisects the city of Hamilton, Ontario. Geological fractures are widespread in the escarpment and result in the formation of unstable blocks of rock subject to erosion through rockfall. This presents structural stability issues of concern due to the proximity of the escarpment to urban infrastructure. We quantify and analyse fracture networks in the escarpment using a combined field- and numerical-modelling-based approach. The location, orientation and aperture of fractures were documented from local outcrops using scanline and area survey methods. Clusters of poles describing the orientation of geological discontinuities were identified in spherical projections, defining three sets: (1) a sub-vertical stratabound set striking N–S, (2) a sub-vertical stratabound set striking E–W, and (3) a set parallel to horizontal sedimentary bedding planes which we infer controlled sub-vertical fracture geometry. Discrete fracture network modelling of fracture sets highlights their high degree of connectivity, and contribution to local geohazards, and quantifies their role in controlling fluid flow through escarpment strata, which is dependent on fracture aperture. Additionally, bedding planes have the potential to act as free surfaces, facilitating stress conditions in which approximately cuboid blocks are produced, and increasing the risk of rockfalls. We conclude that fractures present a first-order control on the fluid-flow properties and stability of the Niagara Escarpment.
Fitted empirical statistical model for the effect of percent urban land use on rising limb event flow acceleration. Rising limb event-scale flow acceleration was estimated using empirical hydrologic ...data with 15-min time resolution for post-freshet seasonal periods between May 26th and November 15th inclusive. The database included 27 watersheds in 11 river systems of Ontario’s Great Lakes Basin. Flow acceleration was modelled using independent variables for total rainfall, watershed area, urban percent land use and baseflow index. The fitted model, on a log scale, is plotted in a solid black line with shaded 95% confidence intervals for mean database values. Actual data for study watersheds are plotted in grey points.
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•High temporal resolution hydrologic records for 27 watersheds sized 38–800km2.•Empirical event-scale hydrologic trends modelled for urban cover 0.1–88%.•Detectable effects on total runoff at ∼4% urbanized watershed.•Event flow acceleration increased with increasing urban cover.•Loss of hydrologic stationarity during a period with no trend in rainfall pattern.
We conducted an empirical hydrological analysis of high-temporal resolution streamflow records for 27 watersheds within 11 river systems in the Greater Toronto Region of the Canadian Great Lakes basin. Our objectives were to model the event-scale flow response of watersheds to urbanization and to test for scale and threshold effects. Watershed areas ranged from 37.5km2 to 806km2 and urban percent land cover ranged from less than 0.1–87.6%. Flow records had a resolution of 15-min increments and were available over a 42-year period, allowing for detailed assessment of changes in event-scale flow response with increasing urban land use during the post-freshet period (May 26 to November 15). Empirical statistical models were developed for flow characteristics including total runoff, runoff coefficient, eightieth and ninety-fifth percentile rising limb event runoff and mean rising limb event acceleration. Changes in some of these runoff metrics began at very low urban land use (<4%). Urban land use had a very strong influence on total runoff and event-scale hydrologic characteristics, with the exception of 80th percentile flows, which had a curvilinear relationship with urban cover. Event flow acceleration increased with increasing urban cover, thus causing 80th percentile runoff depths to be reached sooner. These results indicate the potential for compromised water balance when cumulative changes are considered at the watershed scale. No abrupt or threshold changes in hydrologic characteristics were identified along the urban land use gradient. A positive interaction of urban percent land use and watershed size indicated a scale effect on total runoff. Overall, the results document compromised hydrologic stability attributable to urbanization during a period with no detectable change in rainfall patterns. They also corroborate literature recommendations for spatially distributed low impact urban development techniques; measures would be needed throughout the urbanized area of a watershed to dampen event-scale hydrologic responses to urbanization. Additional research is warranted into event-scale hydrologic trends with urbanization in other regions, in particular rising limb event flow accelerations.
