Proceedings of the Canadian Society for Civil Engineering Annual Conference 2023, Volume 9

Drainage improvement structures are quite common in populated areas from small towns to mega-cities. For small structures, simple hydraulic calculations would be sufficient for design purposes (e.g., empirical or analytical relationships). Often, one-dimensional (1D) hydraulic modeling is required to solve the hydraulics of the project. However, more complex geometries and projects would require more complex solutions. A two-dimensional (2D) model was created to evaluate the complex hydraulics in a large 90° bend culvert and downstream energy dissipation structure. The flow in bends is non-uniform due to normal acceleration (i.e., perpendicular to the main flow direction), and thus, a 1D hydraulic model is not able to simulate the water depths and flow velocities that vary crosswise. In addition, cross-wave effects also exist when dealing with turbulent supercritical flows around a bend structure, which was the case in this project. Positive and negative disturbances emanate from the outer and inner walls, respectively. This pattern is well resolved in the 2D model developed for this project. The concrete box culvert modeled was approximately 2000 ft and was designed to accommodate the 1:100-year flood flow of 1041 ft³/s. After screening a few hydraulic models, the Adaptive Hydraulics (AdH) software was selected to aid with this modeling. AdH is a finite element model that can simulate 2D subcritical and supercritical flows. A lid function was used in the model to correctly model the design geometry for potential pressurized situations and headwater impact at the culvert inlet. Detailed water levels, velocities, and pressure forces, especially at the bend section, were used for the detail design of the culvert. This paper summarizes the methodology of AdH modeling and reviews the results and how they informed the design of culvert structure and energy dissipation basin at the outlet based on the Federal Highway Administration (FHWA), Hydraulic Engineering Circular No. 14. Guideline.

Digital twin modeling involves creating a digital version replicating a physical asset’s characteristics, processes, behaviors, and other attributes. While digital twins have seen wide application across various industries, their use in the built environment is relatively new. Despite different types of digital twins being utilized in this context, there has not been prior research leveraging digital twins to oversee and manage the service levels of potable water infrastructure systems. Given that the operational phase of these infrastructure assets spans the longest duration, the significance of developing a digital twin focusing on service levels is particularly amplified. Service levels aid in strategic decision-making by monitoring and assessing how well infrastructures perform operationally against established service standards. A digital twin focused on service levels can automate the collection of data from an infrastructure system regarding its current services and provide insights into its future performance. This study created a framework based on digital twin modeling for assessing service levels of potable water infrastructure systems. The study’s outcomes align with ISO 55,000 recommendations, emphasizing real-time data collection on service standards, automatic assessment of current service levels, and benchmarking comparisons to offer insights into how well potable water infrastructure systems perform operationally.

Calibration of wastewater collection system models is essential to ensure well-functioning and representative models. However, the calibration process is usually more rigorous and time-consuming than other modelling tasks. Typically, wastewater system calibration involves examining model outputs against measured records. Next, perturbation of sensitive model parameters is necessary to accurately mimic different processes of the existing system and improve the goodness of fit between model predictions and observations. Statistical efficiency measures can guide the calibration process, ensuring good correlation within acceptable tolerance limits. The City of Napier (NCC) employs hydraulic models for long-range strategic and operational planning of its wastewater system, providing the opportunity to address operational issues and develop dynamic master plans. Recently, Stantec collaborated with NCC for the wastewater model build and calibration in which MIKE URBAN was utilized to build a multiple basin-level city-wide wastewater model. This study reviews the dry and wet weather calibration methodology. Model calibration was done in two separate stages for the dry and wet weather flow conditions. In the first stage, flow monitoring data from dry weather periods was used to set parameters such as per capita wastewater loading, diurnal pattern, and base flow for the sub-basins associated with each flow monitoring station. In the second stage, flow monitoring data collected during rainfall events was used to adjust and set hydrological settings for each group of monitored sub-basins. This model was calibrated based on pump station monitoring (PSM) records collected over the years by NCC and throughout this study, in addition to temporary in-pipe flow monitoring data collected during the 2019 winter season. The estimation of inflow and infiltration (I&I) was a critical step in the calibration process using PSM and SCADA data to examine flow trends, including the impact of seasonality and long-term response on wet weather events. Base flow enclosed the base sanitary and industrial flow and groundwater infiltration. The built model accounted for seasonal fluctuations in groundwater level, including dry weather conditions, to determine sewer trunks exceeding capacity due to groundwater infiltration, requiring rehabilitation. These efforts resulted in a good agreement between model predictions and flow records.

Rivers have good potential to contribute to the renewable future of Canada, and river energy converters (REC) typically need to be installed in an array formation or farm layout to maximize their cost efficiency. Optimizing the arrangement of such formations plays a vital role in achieving the array’s maximum effectiveness. In order to analyze the performance of the turbines, a high-definition numerical simulation with fine computational grid gives the most accurate predictions on the performance of a REC array. The Laboratoire de Mécanique des Fluide Numérique (LMFN) of Laval University developed, in collaboration with the National Resources Canada (NRCan), a model approach called the effective performance turbine model (EPTM) that accurately predicts the wake recovery of turbines in an array formation (Bourget in Development and assessment of a modeling method for hydrokinetic turbines operating in arrays, 2018, [1]). However, the computational demand of EPTM inhibits its implementation within a river hydrodynamic model at large scale. Herein, a method is developed to implement EPTM results within TELEMAC-3D, which can be used to predict the drag of a turbine array within a river at reasonable computational cost. To develop the method, the drag coefficients predicted by EPTM are translated to a TELEMAC-3D grid. Inverse distance weighting (IDW) method is employed to ensure smoothly distributed drag coefficients within TELEMAC-3D. Sensitivity analysis was performed to understand the effects of diffusion coefficients in turbulence and their influences on the accuracy of the results. This paper presents the implementation of the EPTM in TELEMAC-3D with simulation examples.

Advances in satellite remote sensing of rivers have made it possible to obtain detailed geometric variations of the riverbed. Such details are important for the study of near-bed flow. This paper uses a 200-m reach of the Nicolet River in Quebec, Canada as an example to demonstrate the usefulness of remote sensing data to the study of near-bed flow. For this river, there has been a threat of declining biodiversity and fish population. Also, floods are frequent, especially during the spring. The focus of this paper is on determining form drag and skin stress at a locally uneven riverbed. The drag plays a significant role in the prediction of sediment transport, channel erosion, and morphological change. The specific objectives of this paper are: (a) to develop an analytical function that describes the local variations in bed level along the thalweg, using satellite images as input, and (b) to calculate the form drag and surface drag. This paper uses multispectral WorldView-3 (WV-3) satellite images of 1.2 × 1.2 m pixel resolution to derive the local protrusions of bed level. These protrusions are considered as macro-scale bed roughness elements. The calculation methods divide the stresses on an element into surface and form components. The results show 73 roughness elements in the 200-m river reach. Although they differ in size, they can be fitted to a Gaussian function. The drag coefficient, C_D, for each of the Gaussian elements is only dependent on shape parameters. Values of C_D for roughness elements range from nearly zero to 0.6. A criterion is proposed to exclude small (or smooth) elements in drag calculations. For flow over roughness elements, there is a distinction between an internal boundary layer, a wake, and an outer boundary layer. Calculations of the total boundary shear stress over roughness elements require total roughness heights. The total boundary shear stress along the river reaches a maximum value of 55 N/m². The results from this study are useful for a further investigation of sediment transport and erosion. The methods discussed are new contributions, more efficient and less expensive than field measurements of flow velocities for estimates of riverbed shear stress.

Municipalities are increasingly dependent on hydraulic modelling tools to design, manage and diagnose urban stormwater systems. For any model application, the accuracy and adequacy of a specific modelling approach, or the lack thereof, define the design solution provided to manage existing problems in the system. Based on model simulation results, municipal planners and engineers take responsibility for funding capital projects to address existing concerns in their stormwater systems, including flooding problems or operability. A deficient model basis would result in projects that do not sufficiently address the storm networks’ real issues and risk the misuse of public resources. Currently, two main hydraulic modelling approaches are applied in the most widely used storm modelling software packages: 1D dual-drainage models and 2D direct rainfall models. With varying model prediction accuracy, level of effort and resource requirements, selecting the right model approach for a specific model application becomes critical. The objective of this study is to inform municipalities and other stormwater utility operators about the conditions and limitations of different modelling approaches, which form the basis upon which investment decisions for future stormwater infrastructure projects are made. In the present study, a real stormwater system in the City of St. Albert, Alberta, was selected as a case study. The system was modelled employing the three stormwater modelling approaches using MIKE+ 2022 software package by DHI. The model build of the different approaches was compared in terms of person-hour, data needs, representativity of the real system behaviour and scalability. In addition, model results were compared and examined against system observations and known issues. Comparison of the output from different model approaches showed that the 2D model was more accurate in simulating the performance of the storm system, especially looking at grid-level surface flows in areas where the pipe system cannot naturally surcharge. The dual-drainage model adequately simulated flows in gutters and ditches, which makes it more suited for the design of these features as an alternative to the rational method.

Drastic increase in global plastic production has resulted in a proportional up-surge in plastic input to the aquatic environment. Microplastic (MP) pollution has detrimental effects on aquatic ecosystem health. Understanding the fate and transport of aquatic these contaminants can help their pollution mitigation. The transport and distribution of MPs in the aquatic environment are influenced by various factors. MPs have diverse physical characteristics, including density, shape, and size, due to their different origins and exposure to weathering processes. Additionally, transport mechanisms such as biofouling and turbulent-induced mixing, generated by factors such as temperature gradient, wind, and sudden changes in topography, can alter the gravity-driven transport of MPs. This numerical study uses a hybrid Lagrangian–Eulerian model to investigate the entrainment and distribution of MPs in a fully developed turbulent flow. Based on our observations, MP particles exhibit a wide range of particle Reynolds numbers, with some falling in the linear Stokesian regime and others in nonlinear transient regimes. The fate of MPs depends on both the hydrodynamic characteristics of the ambient flow and the particle characteristics. Here we used the settling parameter, Stokes number, and the radius of eddy trapping to characterize the distinct transport and mixing behaviour of heavy MPs of different sizes and shapes. Our findings suggest that the shape and size of the MP can affect the trajectory of the particles and, consequently, the instantaneous ambient flow characteristics. Thus, the relative velocity of the particle with respect to the ambient flow, and the drag-driven transport is dominated by the size and shape of the particle.

Groundwater vulnerability is a serious issue at the coastal region of Bangladesh because of the extraction of groundwater and increasing contamination due to salinity intrusion. This study aims to assess the vulnerability of the shallow aquifer of Barisal, one of the severely salinity-affected coastal districts of Bangladesh. In this study, a vulnerability map for Barisal was developed using DRASTIC vulnerability index method in GIS environment. In this method, seven parameters such as water table depth, recharge, aquifer media, soil media, topography, impact of the vadose zone and hydraulic conductivity of the study area were considered for the analysis. From this study, the DRASTIC index value range was found 138–171 for Barisal which indicates that Barisal is moderately to highly vulnerable to contamination. From the analysis, it is seen that 56.73% of the total area of Barisal district lies under moderate vulnerability and 43.27% area under high vulnerability. Muladi, Hizla and Mehendiganj upazillas share major parts of the highly vulnerable zone while other places of this district fall mostly under moderate vulnerability. The result of the study will be helpful to the concerned authority to understand the groundwater vulnerability of identified vulnerable locations of Barisal district and take necessary steps accordingly.

With the declaration of the Human Right to Water in 2012, California has been strategically enacting policies and allocating resources to ensure this fundamental right to all Californians. Reliable provision of drinking water can be hampered by barriers such as water scarcity, contamination, fiscal constraints, and natural or human-made hazards. Many of these challenges disproportionately burden historically marginalized communities which may also have limited power to affect change to their water supply systems. One method of ensuring water security for these underserved communities is through consolidation with a nearby water system. However, the promised benefits of consolidation (e.g., economies of scale, sharing of resources and expertise) are not always realized, which can leave underserved communities with short-term solutions and new water security challenges. In this work, we examine drinking water system consolidations within the state of California to determine whether consolidation has sufficiently provided reliable drinking water to these communities. We use data from the State Water Resources Control Board and the California Drinking Water Needs Assessment to assess the condition and characteristics of drinking water systems. These data show that consolidation receiving systems face lower rates of water supply risks in water quality, accessibility, affordability, and technical financial managerial capacity than non-consolidated systems and tend to be larger in area and population with higher connection density. Over half of all consolidations are motivated by water quality concerns, some of which persist after consolidation. Non-transient non-community water systems make up 17% of all drinking water systems in California but represent 23% of consolidated systems and continue to face post-consolidation risks at a higher proportion than other system types. While consolidation is sufficient to address many water supply challenges, these benefits are not universally experienced. More targeted funding and shorter consolidation timelines may improve universal access to drinking water within California.

A series of laboratory experiments were conducted in the Multiphase Flow Research Laboratory (MFRL) at Lakehead University to investigate the effect of release height on the motion of particle clouds produced from relatively large mass of sand particles. Sand particles with median diameters of D₅₀ = 0.507 mm and an initial volumetric sand concentration of c_o = 60% were released through a 6-mm nozzle. Different release heights were tested in this study providing non-dimensional release heights ranged from η = 1 to 21. A wide range of sand masses was tested and the effect of sand mass and nozzle diameter was represented by an aspect ratio ranged between 46 and 93. The velocity fluctuations and turbulent intensity of sand particles in the cloud were calculated from the time-series data. It was found that particle velocity fluctuations increase with increasing the mass of sand particles and reducing nozzle diameter. The variations of penetration length and width of particle clouds with time were measured and the frontal velocity of particle clouds were calculated from the measurements. The characteristics of particle cloud released above the water surface were compared with that of sand particles released from the water surface as a benchmark test. For sand particles with high sand mass and small nozzle size (i.e., large aspect ratio), cloud’s width increased dramatically when sand particles were released above the water surface (i.e., η > 1). In addition, the horizontal dispersion of sand particles began earlier when sand particles were released above the water surface, and particle clouds reached the cloud’s deeper penetration length and width.

The Stream Ecological Valuation (SEV) was developed by interdisciplinary scientists based on a methodology developed by the US EPA and US Army Corps of Engineers for wetlands. SEV comprises 14 functions and 28 variables that evaluate natural streams’ hydraulic, habitat provision, biotic and biogeochemical parameters. The hydraulic valuation examines the natural flow regime, floodplain particle retention and intact, connectivity for species migrations, and connectivity to groundwater. In 2010, an SEV of Saltwater Creek, a 2.8-km urban stream in Napier, New Zealand, identified significant losses of ecological functions. Numerous structures were categorized as barriers to fish passage, preventing or constraining fish migrations. It was recommended that where practical ecological enhancement is incorporated into the improvements of new structures, existing stream, and flooding studies. The proposed SEV improvement plan required increasing the density of vegetation to provide deeper and slower water flows for fish habitats. However, allowing higher water levels can increase flood risks for surrounding areas. The present work aimed to investigate improving the hydraulic SEV parameters for Saltwater Creek and assess the impact of changing the vegetation scheme along its floodplains. Studied options included (1) low roughness: existing conditions, i.e., mown grass, (2) moderate roughness: low-growing native grasses, sedges, and rushes, and (3) high roughness: diverse native and/or exotic trees and shrubs. Different planting schemes were reviewed to estimate Manning’s roughness coefficients of various vegetation options. MIKE URBAN, MIKE HYDRO, and MIKE 21 modeling frameworks were used to model the storm pipe networks, the open drain flow, and 2-D surface runoff, respectively. Simulations included the 1:100 year 4-h design storm, with an additional option for the 2050 horizon considering future developments and climate changes. Flood extents for different vegetation options were estimated, and respective mitigation plans were developed. These plans comprised oversizing culvert crossings by 50%, cross-section widening, and altering channel morphology. Vegetation options and mitigation plans are being finalized with the City of Napier based on infrastructure conflicts and operational considerations.

Large-scale turbulence coherent structures are defined as the largest conglomerations of eddies with a prevailing sense of rotation. They can be vertical (i.e., rotating around horizontal axes) or horizontal (rotating around vertical axes), and both have already been the object of intensive research in open-channel and river flows. The focus of this work is on large-scale horizontal coherent structures (LSHCSs). In addition to playing an important role in the transport of sediment and pollutants in rivers, LSHCSs have also been related to various fluvial bed and plan forms. Yet, despite numerous literature on the topic, no studies have been carried out so far on LSHCSs in ice-covered flows. This work aims to fill this gap by addressing the existing lack of information on the characteristic scales and life cycle of LSHCSs in such flows. The analysis is based on a series of instantaneous velocity measurements conducted in an 11-m-long and 0.382-m-wide flume. The velocity was measured with the aid of a 2D Micro Acoustic Doppler Velocimeter. The simulated ice cover was made of extruded polystyrene covered with a mesh; a 5-mm gravel was used as bed material. Low-pass filters and continuous wavelet transform were used for the detection and establishment of the length and time scales of the LSHCSs. The results indicate that the simulated ice cover impacts the amplitude of the velocity oscillograms as well as markedly reduces the power intensity of the LSHCSs. Ice covers may also have an effect on the time and length scales of LSHCSs but not a significant one. The results of this work must be viewed as preliminary, as the number of measurements is limited.

Storm-induced wave run-up is responsible for wave overtopping, beach erosion, and flooding. Therefore, it is crucial to simulate such events, especially during hurricanes and nor’easters. Low-fidelity phase-averaged models are often preferred and used for the prediction of wave run-up due to their computational efficiency. However, phase-resolving numerical models have shown great accuracy in predicting wave run-up with much demanding computation resources. In this study, a mapping approach based on machine learning techniques is proposed to rapidly predict high-fidelity numerical simulations given their corresponding low-fidelity results. Specifically, the proposed model maps the wave run-up from the phase-averaged surf-beat of the XBeach model to its corresponding values from the phase-resolving nonhydrostatic mode. Two artificial neural networks were trained to simulate the extreme wave run-up \((R_{2\% } )\) and wave profile, respectively. The simulation results demonstrate the excellent performance of the proposed model in predicting the wave run-up characteristics. As a result, the models are suitable for use in early warning systems, probabilistic risk assessment, and rapid prediction of wave run-up during extreme events.

The interaction between turbulent wall jet and crossflow current affects the morphology of river at the discharge point and significantly impacts riverbed topography. The current paper presents the results of a series of laboratory experiments on scour formation induced by turbulent wall jets in crossflow. The effect of secondary flow on scour formation was also studied by placing the jet in the upstream and downstream of a 90-degree channel bend. The river strength was quantified by the channel Froude number, Fr, and it ranged between 0.017 and 0.36. The jet discharge strength was evaluated by variations of jet Reynolds number, Re, and it varied from 16,190 to 48,402. All experiments were performed in deep submergence condition with jet submergence rates varied between 5.26 and 31.57. The maximum scour depths and scour areas were measured, and the results were compared for different hydrodynamic conditions. Three scour regions were identified and named as the main scour region (I) and the secondary scour regions (i.e., regions II and III). It was found that the second scour region (II) formed for Fr ≥ 0.091 under the effects of crossflow and the jet interaction immediately downstream of the jet. The third scour region (III) formed for Fr ≥ 0.146 due to crossflow separation above the sediment mound. Increasing the jet and channel flow strengths increased the maximum scour depth in scour regions, and maximum scour depths in the main scour region were larger than the other two regions. In relatively high flow strengths (i.e., Re = 48,402 and Fr = 0.17), the maximum scour depth in the second scour region reached to 67% of the maximum scour depth in the main scour region. Experimental results indicated that increasing the values of Re and Fr increased the scour area in both second and third scour regions and the secondary current increased the depth and area of scour in all three regions.

Sediment in a fluvial system impacts biological and physical processes such as fish, macrophytes and insect health, habitat suitability, fluid mechanics, and floods. Alterations to natural sediment transport such as those caused by hydropower dams and associated reservoirs must be understood since the entire ecosystem will be affected. The purpose of this research is to quantify the downstream effects that the Mactaquac Generating Station (MQGS) has on the sediment dynamics in the Wolastoq|Saint John River (W|SJR) in New Brunswick, Canada; we are specifically investigating how the downstream Grand Lake Meadows Complex (GLM Complex) has been affected by the changes in suspended sediment load. In order to understand implications of changes in sediment, we must first estimate how much sediment enters the reservoir, and the relationship between inflowing sediment and depositing sediment. Hydraulic parameters such as total suspended solids (TSS), turbidity and trap efficiency (TE) were used in this research to quantify the amount of suspended sediment entering the reservoir since the construction of the MQGS in 1968. Field data were collected during the summer and fall months to estimate suspended sediment concentrations, and a linear relationship between turbidity and TSS was developed during ice cover months to complete a year-round dataset. The relationships were generated for four different reaches in the lower Wolastoq|Saint John River and were used as a passive method for estimating TSS concentrations. The relationships had R² values of 0.85, 0.88, 0.95 and 0.98 for the Meductic, Longs Creek, MQGS and Bill Thorpe Walking Bridge sites, respectively. In the study region, sediment transport peaks with the high flows during the spring freshet and fall rain storms and reduces with the low flows during the summer and winter months. The results of this research will further the understanding of sediment dynamics locally, and the impacts on the development and formation of the GLM Complex, while also advancing our understanding of sediment dynamics and regulated rivers in general.

Archimedes screw pumps (ASPs) have been used for land drainage, irrigation, and conveyance of mixed media for millennia. Due to their simple, robust design, modern ASPs are commonly used for land drainage and reclamation, as well as flood management and wastewater conveyance. In a climate-impacted future, the development of improved water management technologies is integral; however, design methods for ASPs are not well documented in the published literature. The design of screw pumps seems largely empirical. The leading text in screw pump design was compiled by Nagel in 1968, which predominantly sourced models and material from a Dutch paper by Muysken in 1932. The text uses many simplifications and empirical models based on undocumented experiments. So, there is a need to introduce more data and design insight to the literature to evaluate previous models and develop more in-depth models to predict screw pump performance more accurately. Gathering data from operating screw pumps can be difficult, particularly since characterizing a wide range of operating conditions and screw geometries is desired for modeling purposes; both are conditions that cannot be easily changed in an operating pumping station. So, a Computational Fluid Dynamic (CFD) model was developed to allow for simulation of any screw geometry or operating configuration. The model used OpenFOAM 8 to simulate the two-phase, immiscible flow of water and air through a dynamically mesh, full-scale Archimedes screw pump. A mesh-sensitivity study, and an evaluation study that compared simulated data to previously collected laboratory experiments, demonstrated that the simulation was an accurate approximation of screw pump performance. Once the model was deemed appropriate, it was used to collect data across a wide range of operating conditions and two scale-sized screw pumps.

Extreme floods are one of the most significant threats to the structural stability of hydraulic gravity structures. The water flow conditions, including the related pressure fields and resultant forces, of overtopped gravity dams and spillways are difficult to accurately quantify. Recent advances in CFD (Computational Fluid Dynamics) have made this approach an attractive alternative to physical models. However, prior to using CFD with confidence one has to establish its accuracy in terms of (i) the computational domain and boundary conditions, (ii) the mesh type and refinement, and (iii) the turbulence model. Four benchmarks are proposed herein to evaluate the accuracy of CFD models to assess the condition of overtopped hydraulic structures. The first benchmark compares the nappe trajectories and pressure fields with empirical data from standard ogee spillways. A minimum level of mesh refinement is necessary to achieve convergence of the vertical and horizontal components of the hydrodynamic loads. The second benchmark uses a rectangular crest spillway to study the aeration of a free-falling nappe. Two methods to achieve aeration are compared: adding a pressure outlet to the downstream wall of the spillway in a 2D model and broadening the domain on the downstream portion of a 3D model. Both strategies accurately capture the trajectory, streamlines, and pressure fields compared to experimental results. However, the 2D strategy, while being less computationally expensive, requires prior knowledge of the aeration boundary location. The third benchmark evaluates the accuracy in modelling the profile of a free-falling water stream by integrating the volume fraction of a control volume to obtain its total water mass. That is then compared against an analytical solution. An adaptative refinement around the interface between water and air is required to converge to the analytical solution. The fourth benchmark combines the lessons learned from the previous three into the problem of an overtopped gravity dam section. The numerical results are compared against analytical and empirical estimates. Adequate mesh refinement and boundary conditions are necessary to capture the hydrodynamic forces. By solving these four benchmarks, one would be able to adjust their CFD models to confidently simulate overtopping of hydraulic structures.

In this paper, the river flow regime of the Qu’Appelle River in Saskatchewan, Canada, was evaluated using the artificial neural network under the impacts of climate change. In this regard, this study took advantage of the CanESM2 model to determine future climate of the region. The SDSM model was then adopted to perform downscaling the data produced by the CanESM2. The historical data (climate and hydrometric) were utilized to train networks to determine the amount of snowfall from precipitation as well as the flow regime based on the air temperature, snowfall, and rainfall data. The generated climate data were inputted into the neural network to determine how the changing climate would impact the flow of the Qu’Appelle River. Comparison of the results obtained under climate change and historical scenarios demonstrated that climate change is expected to result in heterogeneous alteration in precipitation and air temperature patterns causing substantial adverse impacts on the flow regime of the Qu’Appelle River.

Information on instantaneous peak flows (IPFs) is generally required for estimating targeted flows for designing various hydraulic structures, informing non-structural measures, and establishing watershed level or regional scale flood envelop curves. Such information is often lacking compared to mean daily flows, which are frequently available at hydrometric gauging stations. Where IPFs are available, missing values are often encountered in instrumental records. In this study, some existing methods for estimating IPFs are reviewed in the historical context and new methods based on multivariate concept are proposed. Machine learning approaches are also investigated and fusion modeling or super-learner notion is introduced within an ensemble modeling framework to synthesize outputs of multiple IPF estimation methods. The study focusses on all gauging stations with natural flow regimes from Canadian Atlantic provinces. Evaluation of the performance of multiple IPF estimation methods and a robust model selection criterion suggest that multiple methods are applicable for the entire region as the idea of a single universal IPF estimation method is not feasible. Therefore, fusion modeling is useful to exploit the strength of individual methods and to synthesize outputs of multiple methods. The outcome of this study is expected to enhance the value of observational records, which in turn will help derive more reliable hydrologic design estimates at locations where observational records of IPFs are either unavailable, limited or contain missing values. Additionally, the study findings will be useful in developing future flood envelop curves to support climate resilience efforts across the region.

The accuracy of hydraulic simulations and flood predictions for a lake–river system highly depends on the accuracy of input data of topobathymetry. Although digital topographic elevation and bathymetry models are available in most cases for Canadian water bodies, there are two major concerns: (i) a lack of ready-to-use topobathymetry digital elevation models (TB-DEMs) for hydraulic modeling; (ii) the inaccuracy of available data, which inevitably causes uncertain predictions. This study used two TB-DEMs of different resolutions for hydraulic simulations of the Lake of Two Mountains in Montreal, Quebec. The hydraulic model used is TELEMAC-2D, a free source-code module that provides the opportunity to develop new models in future studies of floods. One of the two TB-DEMs has a 1-m resolution. The other TB-DEM is developed by integrating bathymetry data from a NONNA-100 database with topographic data from a DEM of a 30-m resolution from the U.S. Geological Survey (USGS); this TB-DEM has a 100-m resolution. The simulation results are compared between the TB-DEMs. The 1-m TB-DEM slightly improves the prediction accuracy, compared to the 100-m TB-DEM. Nevertheless, a finer resolution TB-DEM should be used to capture details of flood inundation such as roads with high elevations (relative to the adjacent waterbody) and the barriers between wet (lakes or rivers) and dry (land) areas. The use of a finer resolution TB-DEM mesh incurs higher computing costs, which hinders real-time simulations and flood forecasting. This study proposes a reliable strategy for hydraulic simulations of river–lake–shore floods. Future efforts may lead to the development of a real-time simulation and flood warning system.

The planform geometries of meandering single-channel rivers are commonly represented and studied using Cartesian coordinates. A major limitation of the use of this coordinate system is that more than one y coordinate may exist for a given x coordinate, which prohibits the use of functional representations of the river channel. For a function \(f:X \to Y\) to be valid, within a set \(X\), each element must map exactly to one element within a set \(Y\). We present three transformations that give functional alternatives to Cartesian representations of river planforms and apply them to six river reaches within the Miramichi River watershed in New Brunswick, Canada. Through the application of these transformations and discussion of the results, we show that the amplitude-based approach is generally not recommended due to potential loss of information and the non-reversible nature of the process. Instead, transformations based on the channel direction (azimuth) and radius of curvature are recommended for general use.

Napier is a city of 66,000 located on the eastern coast of the North Island of New Zealand, in the Hawke's Bay region. The city sits astride an estuary and the Pacific coastline and is separated from the adjacent waters in many places by a long stop bank (i.e. a levee). This stop bank is necessary as some parts of the City of Napier are below mean sea level. Napier's stormwater infrastructure comprises storm pipes, overland conveyance routes, detention ponds, open drainage channels, ocean outfalls, flood gates and many force mains and stormwater pumping stations. Napier City Council engaged Stantec’s Canadian Team to undertake a stormwater modelling and master planning initiative to represent its hydrological and hydraulic systems, assess flooding damages and recommend flood mitigation options. The authors used DHI MIKE FLOOD to conduct a 2D-integrated stormwater modelling exercise and create flood mapping for various return periods. The combination of numerous stormwater pumping stations, force mains, groundwater intrusion and tidal impacts created challenging conditions for modelling and planning. Added to this is the fact that the area is seismically active and experienced a devastating earthquake in 1931, meaning that much of the infrastructure is at increased risk due to ground movement or tsunamis. Modelling and design of flood mitigation measures accounted for anticipated precipitation escalation due to climate change and sea-level rise impacts on a 100-year timescale. Mitigation measures to address future development intensification and new suburban communities were also investigated, and climate change adaptation strategies such as retreating from areas where land is expected to be permanently inundated below sea level were also explored. Ultimately, green infrastructure and volume retention measures were recommended to complement traditional grey infrastructure in the flooding mitigation strategy. The total stormwater system improvements (capital expenditure) recommended over the initial mitigation horizon are projected to be approximately NZ$401.8 M (Napier City stormwater master plan by Stantec, 2020, [1]). Two months following submission of the model and master plan, Napier was struck by an intense downpour which saw 420% of the average monthly precipitation fall in just 24 h, exceeding a 250-year return period on some durations. Observed flooding locations confirmed the model-predicted locations closely.