Browsing by Author "Westbrook, Cherie"
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Item Beaver dam capacity of Canada’s boreal plain in response to environmental change(Springer Nature, 2020) Stoll, Nichole-Lynn; Westbrook, CherieEnvironmental changes are altering the water cycle of Canada’s boreal plain. Beaver dams are well known for increasing water storage and slowing flow through stream networks. For these reasons beavers are increasingly being included in climate change adaptation strategies. But, little work focuses on how environmental changes will affect dam building capacity along stream networks. Here we estimate the capacity of the stream network in Riding Mountain National Park, Manitoba, Canada to support beaver dams under changing environmental conditions using a modelling approach. We show that at capacity, the park’s stream network can support 24,690 beaver dams and hold between 8.2 and 12.8 million m3 of water in beaver ponds. Between 1991 and 2016 the park’s vegetation composition shifted to less preferred beaver forage, which led to a 13% decrease in maximum dam capacity. We also found that dam capacity is sensitive to the size of regularly-occurring floods— doubling the 2-year flood reduces the park’s dam capacity by 21%. The results show that the potential for beaver to offset some expected climatic-induced changes to the boreal water cycle is more complex than previously thought, as there is a feedback wherein dam capacity can be reduced by changing environmental conditions.Item Prairie Hydrological Model Study Progress Report, April 2008(Centre for Hydrology, University Saskatchewan, Saskatoon, Saskatchewan, 2008) Pomeroy, John; Westbrook, Cherie; Fang, Xing; Minke, Adam; Guo, XulinThis report is an update on the progress made over the first 12 months of the Prairie Hydrological Model Study and corresponds to Milestone #3. In summary, we have characterized the 2007-2008 Hydrological Year for modeling by installing weather, soil moisture, rainfall and pond level recording stations, observing summer evaporation, fall freeze-up and winter snowpack development to the start of melt. We have also made progress on wetland and basin characterization using remote sensing and other spatial information, and begun analysis of hydrometeorological data.Item Prairie Hydrological Model Study Progress Report, December 2008(Centre for Hydrology, University Saskatchewan, Saskatoon, Saskatchewan, 2009) Pomeroy, John; Westbrook, Cherie; Fang, Xing; Brown, Tom; Minke, Adam; Guo, XulinThis report is an update on progress made to the middle of December 2008, corresponding to “Milestone Month 20”. According to our study plan, at this milestone “we will have completed a wetland module and with evaluation on Smith Creek Research Basin and archival data available at the Centre for Hydrology (Objective 3, 4)”. More specifically, Objectives 3 and 4 are stated as: • Objective 3: A physically based, hydrological response unit-based hydrological model, (the Prairie Hydrological Model), will be developed that is suitable for multiple season simulation of the hydrology of the Canadian Prairie environment. The model will be capable of predicting water balance, soil moisture, snow cover, actual evaporation and streamflow on a daily time-step with minimal calibration of model parameters from streamflow records. The model will contain a wetland module that includes assigned variable drainage rates from the wetland. The intended basins would drain to a stream or internally drained lake/wetland, with basin size to be greater than ~1 km2 and less than ~250 km2. • Objective 4: The Prairie Hydrological Model will be evaluated at Smith Creek through hydrological simulation and quantitative analysis of multi-objective criteria, including streamflow and wetland extent. Whilst calibration will be minimised and limited to non-physical aspects of the model, certain parameters will be optimised from these comparisons. For streamflow, both annual and peak flows are parameters of interest. For wetlands, seasonal extent is the parameter of interest. Outlined below are the research activities regarding these two objectives, beginning with a description of the model created with the Cold Regions Hydrological Modelling Platform (CRHM), the CRHM-Prairie Hydrological Model, or CRHM-PHM, followed by a description of the addition of the wetland module, and concluding with preliminary results from CRHM-PHM evaluations at Smith Creek.Item Quantifying relative contributions of source waters from a subalpine wetland to downstream water bodies(Wiley Online Library, 2022) Hathaway, Julia M.; Westbrook, Cherie; Rooney, Rebecca; Petrone, Richard; Langs, Lindsey E.Subalpine regions of the Canadian Rocky Mountains are expected to experience continued changes in hydrometeorological processes due to anthropogenically mediated climate warming. As a result, fresh water supplies are at risk as snowmelt periods occur earlier in the year, and glaciers contribute less annual meltwater, resulting in longer growing seasons and greater reliance on rainfall to generate runoff. In such environments, wetlands are potentially important components that control runoff processes, but due to their location and harsh climates their hydrology is not well studied. We used stable water isotopes of hydrogen and oxygen (δ2H and δ18O), coupled with MixSIAR, a Bayesian mixing model, to understand relative source water contributions and mixing within Burstall Wetland, a subalpine wetland (1900 m a.s.l.), and the larger Burstall Valley. These results were combined with climate data from the Burstall Valley to understand hydrometeorological controls on Burstall Wetland source water dynamics over spatiotemporal timescales. Our results show that the seasonal isotopic patterns within Burstall Wetland reflect greater reliance on snowmelt in spring and rainfall in the peak and post-growing season periods. We found a substantial degree of mixing between precipitation (rain and snow) and stored waters in the landscape, especially during the pre-growing season. These findings suggest that longer growing seasons in subalpine snow-dominated landscapes put wetlands at risk of significant water loss and increased evaporation rates potentially leading to periods of reduced runoff during the peak- growing season and in extreme cases, wetland dry out.Item Relative Effectiveness of Four Different Guards In Preventing Beaver Cutting of Urban Trees(Oxford Academic, 2022) Westbrook, Cherie; England, KirbyBeavers are expanding into cities as they recolonize their historic range. While they increase the ecological functioning of urban green areas, human-beaver conflicts occur. Public support to deal with conflicts has shifted from population to forage control. Tree guards are becoming popular with management personnel in North America and Europe to reduce damage to valuable trees. The problem is that this management technique has not been studied. We inventoried the tree guard types in use in natural and manicured river parks in the City of Saskatoon, Canada, determined their adherence to an installation protocol by measuring guard dimensions, and assessed the relative effectiveness of guards in protecting trees from beaver cutting. The inventory revealed that four types of tree guards are in use, ranging from light gauge chicken wire to heavy gauge chain link fencing. Overall, 11% of the trees with guards that we inventoried were cut by beavers, but variation among guard types was observed. Less than 10% of trees with type i and ii guards were beaver cut whereas 17% of trees with types iii and iv guards were beaver cut. Fewer trees were cut when there was adherence to installation protocol, regardless of guard type. Cut trees with guard types i, iii and iv experienced both minor and major damage whereas cut trees with guard type ii experienced only minor damage. The study results have implications for developing effectiveness and implementation monitoring plans for tree guards as part of an overall beaver management plan.Item A Review of Canadian Prairie Hydrology: Principles, Modelling and Response to Land Use and Drainage Change(Centre for Hydrology, University Saskatchewan, Saskatoon, Saskatchewan, 2007) Fang, Xing; Minke, Adam; Pomeroy, John; Brown, Tom; Westbrook, Cherie; Guo, Xulin; Guangul, SeifuThis report reviews research on the hydrological cycle, runoff generation, hydrological modelling and the influence of changes to land cover and wetlands on the same for the Canadian Prairies. The purpose of this report is to identify and examine the major processes that are responsible for prairie hydrology as well as the impacts of land cover change such as wetland drainage on water storage and on the streamflow hydrograph. The objective of this report is to propose hydrological modelling techniques; these techniques can contribute to the development of a predictive tool in the form of a prairie hydrological model. It is intent to utilize such a hydrological model to evaluate the impacts of wetland drainage and restoration as well as changes in the surrounding upland land use on downstream hydrology. Hydrology in the Canadian Prairie region is complex and highly varied. Only one third of annual precipitation occurs over the winter and the surface snow water equivalent distribution is highly heterogeneous due to wind redistribution of snow during blowing snow storms. Blowing snow can transport and sublimate as much as 75% of annual snowfall from open prairie fields. The formation of drifts from windblown snow lengthens the spring runoff season and modulates the peak spring flows. The frozen state of mineral soils results in rapid snowmelt runoff in the springtime, which produces 80% or more of annual local runoff. The prairie region is characterized by glacially-formed depressions; these depressions fill with water to form pothole sloughs and wetlands and are very important to prairie hydrology due to their surface storage capacity. A fill-and-spill runoff mechanism is identifiable in prairie basins that are dominated by these surface depressions where flow does not commence until all storage in the depressions is filled. This results in an episodic and rapid increase in contributing area during peak runoff events. However outside of these events much of the prairie landscape is non-contributing to streamflow and even in the most extreme runoff events, some prairie basins are internally drained and never contribute to streamflow. This fill and spill phenomenon is in contrast to forms of hydrological storage found in temperate regions in which the flow rate is proportional to storage. Because of depressional storage and poorly and internally drained basins, most surface runoff in the prairie region does not contribute to the major river systems. Hydrological processes in the prairie region are sensitive to the land cover and climate change. Wetlands can be completely dried out when surrounded by native grassland rather than agricultural fields. Droughts are frequent on the Canadian Prairies. Lower precipitation and higher air temperature are the common characteristics of droughts; surface snowmelt runoff is largely suppressed and can even completely cease when warmer (e.g. 5 ºC increase of temperature) or drier (e.g. 50% decrease of precipitation) conditions develop. The Cold Regions Hydrological Model platform (CRHM) is a “state-of-the-art” physically-based hydrological model designed for the prairie region. CRHM is based on a modular, object-oriented structure in which component modules represent basin descriptions, observations, or physically-based algorithms for calculating hydrological processes. Preliminary tests show reasonable performance of CRHM in simulating the water balance and streamflow hydrograph for prairie regions. The model also shows capabilities to simulate impact of land use change and climate change on hydrological processes and streamflow. Further work in CHRM will be development of surface storage and surface routing models that are suitable for modelling hydrology in the prairie wetland region.Item Thermal Characteristics of a Beaver Dam Analogues Equipped Spring-Fed Creek in the Canadian Rockies(MDPI, 2021) MUNIR, TARIQ; Westbrook, CherieBeaver dam analogues (BDAs) are becoming an increasingly popular stream restoration technique. One ecological function BDAs might help restore is suitable habitat conditions for fish in streams where loss of beaver dams and channel incision has led to their decline. A critical physical characteristic for fish is stream temperature. We examined the thermal regime of a spring-fed Canadian Rocky Mountain stream in relation to different numbers of BDAs installed in series over three study periods (April–October; 2017–2019). While all BDA configurations significantly influenced stream and pond temperatures, single- and double-configuration BDAs incrementally increased stream temperatures. Single and double configuration BDAs warmed the downstream waters of mean maxima of 9.9, 9.3 °C by respective mean maxima of 0.9 and 1.0 °C. Higher pond and stream temperatures occurred when ponding and discharge decreased, and vice versa. In 2019, variation in stream temperature below double-configuration BDAs was lower than the single-configuration BDA. The triple-configuration BDA, in contrast, cooled the stream, although the mean maximum stream temperature was the highest below these structures. Ponding upstream of BDAs increased discharge and resulted in cooling of the stream. Rainfall events sharply and transiently reduced stream temperatures, leading to a three-way interaction between BDA configuration, rainfall and stream discharge as factors co-influencing the stream temperature regime. Our results have implications for optimal growth of regionally important and threatened bull and cutthroat trout fish species.Item Ultrahigh-resolution mapping of peatland microform using ground-based structure from motion with multiview stereo(American Geophysical Union (AGU) [Client Organization]; Wiley [Commercial Publisher], 2016) Mercer, Jason; Westbrook, CherieMicroform is important in understanding wetland functions and processes. But collecting imagery of and mapping the physical structure of peatlands is often expensive and requires specialized equipment. We assessed the utility of coupling computer vision-based structure from motion with multiview stereo photogrammetry (SfM-MVS) and ground-based photos to map peatland topography. The SfM-MVS technique was tested on an alpine peatland in Banff National Park, Canada, and guidance was provided on minimizing errors. We found that coupling SfM-MVS with ground-based photos taken with a point and shoot camera is a viable and competitive technique for generating ultrahigh-resolution elevations (i.e., <0.01 m, mean absolute error of 0.083 m). In evaluating 100+ viable SfM-MVS data collection and processing scenarios, vegetation was found to considerably influence accuracy. Vegetation class, when accounted for, reduced absolute error by as much as 50%. The logistic flexibility of ground-based SfM-MVS paired with its high resolution, low error, and low cost makes it a research area worth developing as well as a useful addition to the wetland scientists’ toolkit.Item Using StableWater Isotopes to Analyze Spatiotemporal Variability and Hydrometeorological Forcing in Mountain Valley Wetlands(MDPI, 2022) Hathaway, Julia M.; Petrone, Richard; Westbrook, Cherie; Rooney, Rebecca; Langs, LindseyWetlands in Montane and Subalpine Subregions are increasingly recognized as important hydrologic features that support ecosystem function. However, it is currently not clear how climate trends will impact wetland hydrological processes (e.g., evaporative fluxes) across spatiotemporal scales. Therefore, identifying the factors that influence wetland hydrologic response to climate change is an important step in understanding the sensitivity of these ecosystems to environmental change. We used stable water isotopes of hydrogen and oxygen (δ2H and δ18O), coupled with climate data, to determine the spatiotemporal variability in isotopic signatures of wetland source waters and understand the influence of evaporative fluxes on wetlands in the Kananaskis Valley. Our results show that the primary runoff generation mechanism changes throughout the growing season resulting in considerable mixing in wetland surface waters. We found that evaporative fluxes increased with decreasing elevation and that isotopic values became further removed from meteoric water lines during the late peak- and into the post-growing seasons. These findings suggest that a change in the water balance in favor of enhanced evaporation (due to a warmer and longer summer season than present) will not only lead to greater water loss from the wetlands themselves but may also reduce the water inputs from their catchments.