Cherie Westbrook

• PhD
• Professor (Full) at University of Saskatchewan

Beavers modify riverine systems by building dams that alter downstream fluxes of water and sediment. Where beavers have been lost and stream channels degraded, beaver dam analogs (BDAs) are being used to mimic the effects of beaver engineering. Central to the success of these structures in accelerating stream recovery is creating similar ecosystem...

Beavers, Castor canadensis in North America and Castor fiber in Eurasia, are widely referred to as nature's engineers due to their ability to rapidly transform diverse landscapes into dynamic wetland ecosystems. Few other organisms exhibit the same level of control over local geomorphic, hydrologic, and ecological conditions. Though freshwater ecos...

Beavers modify stream channels and their floodplains by building dams that alter downstream fluxes of water and sediment. Where beavers have been lost and stream channels degraded, beaver dam analogues (BDAs) are being used to mimic the effects of beaver engineering. Central to the success of these structures in accelerating stream recovery is crea...

This chapter in the Rivers of North America: 2nd Edition covers the physical and ecological characteristics of the Nelson and Churchipp River Basins, with particular focus on the Beaver, Bow, Sibbald, Qu'Appelle, Smith, Dauphin, and Otter Tail Rivers.

Peatlands in mountain regions commonly occur in valley bottoms and tend to have a complex soil profile due to the geomorphically dynamic environment. Characterization of the specific yield for mountain peatlands is rare despite that it is a parameter that is critical for modelling water table position, determining the water release rate and simulat...

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 sea...

Beavers 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 r...

Wetlands 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...

Beavers are a keystone species known to strategically impound streamflow by building dams. Beaver colonization involves upstream ponding; after abandonment, the dams degrade, and the ponds slowly drain. This ponding-draining cycle likely modifies peatland nutrient availability, which is an important control on vegetation distribution and productivi...

Beaver (Castor canadensis and Castor fiber) are regarded widely as ecosystem engineers and the dams they create are well-known for their ability to drastically alter the hydrology of rivers. As a result, beaver are increasingly being included in green infrastructure practices to combat the effects of climate change and enhance ecosystem resilience....

Beavers have recolonized much of their historic range throughout the northern hemisphere and numerous studies have documented their habitat preferences and foraging behavior in rural riparian areas. Beavers, however, are also recolonizing waterways in cities, yet there has been little study of habitat use and foraging practices in these managed, ur...

Ecosystem services valuation is not new, but few approaches have been developed to support ecosystem service consideration at the strategic level of futures-based planning. This paper demonstrates a practical, strategic environmental assessment approach to incorporate the valuation of ecosystem services in a futures-based assessment to support land...

Beaver 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...

Beaver are important agents of plant disturbance in wetland and riparian environments. They have two roles as a plant disturbance agent. They have earned the title of ecosystem engineers as one of their more remarkable aspects is their ability to alter physical ecosystem processes through building dam and canal networks. Beaver also are herbivores,...

Beaver dam analogues (BDAs) are intended to simulate natural beaver dam eco-hydrological functions including modifying stream hydrology and enhancing stream-riparian hydrological connectivity. River restoration practitioners are proactively deploying BDAs in thousands of degraded streams. How various BDAs or their configurations impact stream hydro...

Environmental 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 buildi...

It is becoming increasingly popular to reintroduce beaver to streams with the hopes of restoring riparian ecosystem function or reducing some of the hydrological impacts of climate change. One of the risks of relying on beaver to enhance ecosystem water storage is that their dams are reportedly more apt to fail during floods which can exacerbate fl...

If the aim of flood risk management (FRM) is to increase society’s resilience to floods, then a holistic treatment of flood risk is required that addresses flood prevention, defence, mitigation, preparation, and response and recovery. Progressing resilience-based management to flood risk requires both diversity and coordination of policy across mul...

Mountain fens are limited in their spatial extent, but are vital ecosystems for biodiversity, habitat, and carbon and water cycling. Studies of fen hydrological function in northern regions indicate the timing and magnitude of runoff is variable, with atmospheric and environmental conditions playing key roles in runoff production. How the complex e...

River management based solely on physical science has proven to be unsustainable and unsuccessful, evidenced by the fact that the problems this approach intended to solve (e.g., flood hazards, water scarcity, and channel instability) have not been solved and long‐term deterioration in river environments has reduced the capacity of rivers to continu...

Beavers ingeniously alter environments to suit their needs of predator protection and food access, creating widespread effects on surface waters throughout their range. Beaver are thus considered the quintessential ecosystem engineer. They “engineer” landscapes largely by building dams across low-order streams to retain water. Dam building changes...

Streamflow response in Boreal Plains catchments depends on hydrological connectivity between forested uplands, lakes, and peatlands, and their hydrogeomorphic setting. Expected future drying of the Boreal Plains ecozone is expected to reduce hydrological connectivity of landscape units. To better understand runoff generation during dry periods, we...

Hyporheic exchange is important in increasing stream water transit time through basins and enhancing redox-sensitive biogeochemical reactions influencing downstream water quality. Such exchange may be enhanced by beaver dams which are common throughout low order streams including those originating in peatlands. To understand the influence of beaver...

Major flood events are likely to happen more frequently and be more severe under changing land use and climatic conditions. Adapting to floods using resilience-based flood risk management (FRM) policies and initiatives is a more appropriate solution than relying solely on flood defence structures or disaster recovery programmes. The primary authori...

Beaver dams are known to raise water tables in mineral soil environments but very little is known about their impact in wetlands, such as peatlands. Peatlands tend to have shallow water tables, and the position and tendency of the water table to fluctuate (i.e. stability) is a factor controlling the system's ability to store carbon and water. Many...

Modelling nutrient transport during snowmelt in cold regions remains a major scientific challenge. A key limitation of existing nutrient models for application in cold regions is the inadequate representation of snowmelt, including hydrological and biogeochemical processes. This brief period can account for more than 80% of the total annual surface...

The environmental management literature suggests that resilience is key to managing complex systems and reducing vulnerability resulting from uncertainty and unexpected change. Yet, flood risk management (FRM) has emerged largely from a culture of resistance. This paper takes the pulse of the current state of FRM research, with a focus on how the s...

Beaver ponds are surface-water features that are transient through space and time. Such qualities complicate the inclusion of beaver ponds in local and regional water balances, and in hydrological models, as reliable estimates of surface-water storage are difficult to acquire without time- and labour-intensive topographic surveys. A simpler approac...

Carbon (C) dynamics in northern peatlands are an important factor in the global C balance under climate change scenarios. They are microbially driven and influenced by the chemical composition of organic matter. Peatlands in the Rocky Mountains are usually formed on mineral sediments or developed with interbedded mineral lenses, which have been fou...

Microform 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 multi-view stereo photogrammetry (SfM-MVS) and ground-based ph...

Beaver ponds are surface water features that are transient through space and time. Such qualities complicate the inclusion of beaver ponds in local and regional water balances, and in hydrological models, as reliable estimates of surface 10 water storage are difficult to acquire without time and labour intensive topographic surveys. A simpler appro...

Soil profiles in mountain peatlands commonly show complex stratigraphy with both underlying and interbedded mineral sediments. The presence and types of mineral sediments may affect nutrient gradients via the vertical and horizontal movements of groundwater, which further influences biogeochemical processes, especially for deeper peat adjacent to m...

Sibbald Research Wetland is a 1.3 km2 peatland in the foothills of the Rocky Mountains. The primary research foci are 1) the influence of beaver ponds on mountain peatland hydrology and 2) the potential influence of climate change on these beaver-impacted peatlands. This paper summarizes initial results and implications of the research.

Beavers (Castor spp.) are ecosystem engineers and important modifiers of freshwater ecosystems. They create impoundments that flood the surrounding landscape and modify the flow of materials through streams, thus potentially increasing nutrients, productivity and the availability of toxic methyl mercury (MeHg) to downstream food webs. Here we quant...

The Boreal Plains Ecozone ( BPE ) in Western Canada is expected to be an area of maximum ecological sensitivity in the 21st century. Successful climate adaptation and sustainable forest management require a better understanding of the interactions between hydrology, climate, and vegetation. This paper provides a perspective on the changing water cy...

To illustrate the hydrological impact of climate and land use change on an unregulated basin, the agriculture and wetland dominated Smith Creek Research Basin (SCRB) was examined in detail. Streamflows (1975-1994) show behaviour typical of the Canadian Prairies – generation primarily by snowmelt and cessation in May due to lack of runoff or groundw...

Marmot Creek Research Basin in the Canadian Rockies has been the site of intensive streamflow, groundwater, snow accumulation, precipitation, and air temperature observations at multiple elevations. The basin was instrumented in 1962, subjected to forestry experiments in the mid-1970s and experienced extreme flooding in 2013. Climate change, forest...

Globally, greenhouse gas budgets are dominated by natural sources, and aquatic ecosystems are a prominent source of methane (CH4) to the atmosphere. Beaver (Castor canadensis and Castor fiber) populations have experienced human-driven change, and CH4 emissions associated with their habitat remain uncertain. This study reports the effect of near ext...

Mountain wetlands, although limited in their spatial extent, provide many important hydrological and ecological services. There is a need to know existing beaver habitation patterns across mountain wetlands because of emerging inter-est in using beaver to restore and protect riparian and wetland habitats. However, there exist few inventories of wet...

Wetland habitat continues to be lost to cumulative effects of development on the landscape. Part of the problem is that there currently exists only limited guidance as to how to use the existing scientific tools, conceptual frameworks and guidance documents to advance cumulative effects assessment (CEA) from the project scale to the broader regiona...

Increased land use intensity has been shown to adversely affect aquatic ecosystems. Multiple landscape stressors interact over space and time, producing cumulative effects. Cumulative Effects Assessment is the process of evaluating the impact a development project may have on the ecological surroundings, but several challenges exist that make curre...

Hydrological and geomorphological processes are influenced by beaver (. Castor canadensis and C. fiber) activities in aquatic and semi-aquatic environments throughout much of North America, Eurasia, and the austral archipelago of Chile and Argentina. The main hydrologic signature of beaver activities varies with hydrogeomorphic setting - along conf...

Ecohydrology is now recognized as an interdisciplinary field, and as it grows, there needs to be greater awareness and dialogue on its focus and future direction. To take a ‘bearings’ on where we are, 339 ecohydrological articles published between January 2000 and December 2011 in two databases were surveyed. We found that 72% of the studies addres...

Hydrological and geomorphological processes are influenced by beaver (Castor canadensis and C. fiber) activities in aquatic and semi-aquatic environments throughout much of North America, Eurasia, and the austral archipelago of Chile and Argentina. The main hydrologic signature of beaver activities varies with hydrogeomorphic setting—along confined...

The cold regions hydrological model (CRHM) platform, a physically based hydrological model using a modular and object-oriented structure, has been applied for simulating the redistribution of snow by wind, snowmelt, infiltration, evapo-transpiration, soil moisture balance, surface depression storage and run-off routing. Land use and land cover clas...

Intensification of agriculture has led to renewed efforts to drain wetlands throughout North American prairies. It is perceived to threaten downstream ecosystem health through enhancing nutrient, bacteria and salt loading. An experiment was conducted to determine temporal variations in wetland solute storage and export upon drainage. Water quality...

The flow of stream water through riparian soils is known to influence the nitrogen (N) patterns in streams. Needed is an improved understanding of how filtration capacity, the extent to which water residence time and riparian sediment hydraulic conductivity regulates water characteristics, acts to influence the concentration of N that emerges back...

Investigation into the effects of beaver dams on hyporheic fluxes in channelled peatlands is needed to better understand how biological processes drive stream-riparian area connections and thus nutrient export, and to improve our overall conceptual model of water storage and flow through peatlands. The objective of this study was to determine the i...

Fast-paced watershed change, driven by anthropogenic development, is threatening the sustainability of freshwater resources across the globe. Developments within watersheds interact in a manner that is additive and synergistic over space and time. Such cumulative environmental effects are defined as the results of actions that are individually mino...

We examined how beaver dams affect key ecosystem processes, including pattern and process of sediment deposition, the composition and spatial pattern of vegetation, and nutrient loading and processing. We provide new evidence for the formation of heterogeneous beaver meadows on riverine system floodplains and terraces where dynamic flows are capabl...

The Prairie Pothole Region (PPR) of North America contains millions of wetlands in shallow depressions that have potential to store a significant volume of surface water. Assessing and modeling the effect of wetland storage on streamflow requires accurate methods to quantify wetland water volume. Currently, many methods rely on utilizing the strong...

The prairie pothole region is dotted with millions of pothole wetlands. These wetlands provide important habitat for numerous wildlife species. Potholes are small, shallow marshes that typically lack surface water connections and have been shown to trap nutrients, ions, and bacteria from catchment runoff. Approximately 70% of the potholes located i...

Fast-paced watershed change, driven by anthropogenic development, is threatening the sustainability of freshwater resources across the globe. The accumulation of multiple landscape stressors that interact over space and time are defined as cumulative effects and are subject to Cumulative Effects Assessment (CEA), the process of evaluating the impac...

Soil moisture and ground thaw state are both indicative of a hillslope's ability to transfer water. In cold regions, in particular, it is widely known that the depth of the active layer and wetness of surface soils are important for runoff generation, but the diversity of interactions between ground thaw and surface soil moisture themselves has not...

The companion paper (Guan et al., 2010) demonstrated variable interactions and correlations between shallow soil moisture and ground thaw in soil filled areas along a wetness spectrum in a subarctic Canadian Precambrian Shield landscape. From wetter to drier, these included a wetland, peatland and soil filled valley. Herein, water and energy fluxes...

Soil moisture and ground thaw state are both indicative of a hillslope's ability to transfer water. In cold regions, in particular, it is widely known that the depth of the active layer and wetness of surface soils are important for runoff generation, but the diversity of interactions between ground thaw and surface soil moisture themselves has not...

The companion paper (Guan et al., 2010) demonstrated variable interactions and correlations between shallow soil moisture and ground thaw in soil filled areas along a wetness spectrum in a subarctic Canadian Precambrian Shield landscape. From wetter to drier, these included a wetland, peatland and soil filled valley. Herein, water and energy fluxes...

The Cold Regions Hydrological Modelling platform (CRHM) was used to create a prairie hydrological model for Smith Creek Research Basin (~400 km2), east-central Saskatchewan, Canada. Physically based modules were sequentially linked in CRHM to simulate snow processes, frozen soils, variable contributing area and wetland storage and runoff generation...

The Prairie Pothole Region (PPR) of North American contains millions of wetlands that provide important hydrological and ecological functions. Modeling these processes relies on relationships that relate wetland water depth to volume. Methods suitable for investigating water storage in regularly shaped wetlands have already been developed when two...

The eastern Canadian Prairies are dominated by cropland, pasture, woodland and wetland areas. The region is characterized by many poor and internal drainage systems and large amounts of surface water storage. Consequently, basins here have proven challenging to hydrological model predictions which assume good drainage to stream channels. The Cold R...

Novel approaches addressing aquatic cumulative effects over broad temporal and spatial scales are required to track changes and assist with sustainable watershed management. Cumulative effects assessment (CEA) requires the assessment of changes due to multiple stressors both spatially and temporally. The province of Alberta, Canada, is currently ex...

The eastern Canadian Prairies are a region of cropland, pasture, woodland and wetlands. The region is characterized with many poor and internal drainage systems and large surface water storage terms, so watersheds here have proven challenging to hydrological models that assume good drainage to a stream. The cold climate means that snow redistributi...

The ubiquitous presence of frozen ground in cold regions creates a unique dynamic boundary issue for subsurface water movement and storage. We examined the relationship between ground thaw and spatiotemporal soil moisture patterns at three sites (peatland, wetland and valley) near Yellowknife NT. Thaw depth and near-surface soil moisture were measu...

There are millions of wetlands in shallow depressions on the North American prairies but the quantity of water stored in these depressions remains poorly understood. Hayashi and van der Kamp (2000) used the relationship between volume (V), area (A) and depth (h) to develop an equation for estimating wetland storage. We tested the robustness of thei...

Riparian areas in mountain valleys serve as collection points for local precipitation, hillslope runoff, deeper groundwater, and channel water. Little is known about how complex hydrological interactions among these water sources govern riparian water table dynamics, particularly on an event basis partly owing to a lack of high frequency spatial an...

Dynamic exchange of water across the stream-riparian zone interface is important in increasing stream water transit time through basins and enhancing redox-sensitive biogeochemical reactions that influence downstream water quality and ecosystem health. Such exchange may be enhanced by beaver dams, which are common throughout lower-order streams in...

Channel structure, riparian zone structure, and sediment transport capacity were investigated for Sandown Creek, a stream in the East Kootenay region of British Columbia where beaver dams were removed in the late 1980s to "improve" fish passage and flood conveyance. A series of historical aerial photographs taken over a 36-year period between 1968...

Floodplains of broad mountain valleys serve as collection points for local precipitation, hillslope runoff, deeper groundwater, and channel water. Little is known about how complex hydrological interactions among these water sources govern floodplain water table dynamics, particularly on an event basis partly owing to a lack of high frequency spati...

Several recent studies have examined the dynamics of surface soil moisture patterns in relation to hydrological connectivity at the hillslope scale. Seasonally or perennially frozen ground acts as a near- impermeable layer that affects the movement of soil water over much of the world, but seasonal changes in frozen ground and its impact on surface...

Hyporheic zones are dynamic areas important in increasing stream water transit time through basins and enhancing redox-sensitive biogeochemical reactions that influence downstream water quality and ecosystem health. Hyporheic flowpath length and complexity may be increased by beaver dams, which are common throughout lower-order streams in North Ame...

We investigate herein the hypothesis that there is a significant relationship between bed particle mobility and benthic invertebrate abundance in the gravel-bed channel of the upper Colorado River in Rocky Mountain National Park. A large diversion channel called the Grand Ditch normally diverts a significant portion (∼50%) of the annual snowmelt ru...

The heterogeneous Boreal Shield forest in Canada is one of the most extensive pristine forests remaining in the world and is being intensely harvested. We studied the spatial variability of organic and inorganic N cycling processes in three Boreal Shield catchments in northwestern Ontario for 2 years before and 1 year following clearcutting. Net N...

broad alluvial valley during the summers of 2002-2005. We studied a 1.5 km reach of the fourth-order Colorado River in Rocky Mountain National Park (RMNP), Colorado, USA. The beaver dams and ponds greatly enhanced the depth, extent, and duration of inundation associated with floods; they also elevate the water table during both high and low flows....

Slope wetlands generally occur at breaks in slope where discharging ground water maintains moist soil conditions. They often are found on the perimeter of highly permeable alluvial fans, but there have been no detailed hydrologic studies of these particular wetlands. We combined stream and spring flow measurements with five years of water-level and...

Slope wetlands generally occur at breaks in slope where discharging ground water maintains moist soil conditions. They often are found on the perimeter of highly permeable alluvial fans, but there have been no detailed hydrologic studies of these particular wetlands. We combined stream and spring flow measurements with five years of water-level and...

Gross and net nitrogen (N) ammonification and nitrification were measured in soils from an uncut and recently cut upland and peatland conifer stand in northwestern Ontario, Canada. Rates of gross total inorganic N immobilization were similar to gross mineralization, resulting in low net mineralization rates in soils from all four upland and peatlan...

Net mineralization and nitrification in surface forest soils were measured in upland forest stands and valley peatlands using in situ soil incubations at two headwater catchments of Harp Lake, Ontario from July 1995 to October 1996. No difference in either net N mineralization or nitrification was observed between the two adjacent catchments despit...

Spring peak runoff and beaver dams alter stream stage, and therefore control the position of the water table in riparian wetlands. This study poses the hypothesis that beaver, by building cross-channel dams, can maintain higher groundwater levels in riparian wetlands than low recurrence interval floods. Water level data from approximately 200 wells...

Thesis (Ph.D.)--Colorado State University, 2005. Includes bibliographical references.