Article

Hydrology of a Prairie Slough

June 1993
Journal of Hydrology 146(1-4):175-207

June 1993
146(1-4):175-207

Authors:

A three year study was carried out at a prairie slough to determine the hydrological processes occurring in the wetland and its surrounding uplands. On the upland slopes, snow accumulation was highly uneven, giving rise to spatial variations in infiltration and overland flow during melt. Rainfall distribution was more uniform but much of it was lost to evaporation, leaving minor amounts to groundwater recharge or runoff to the slough. The slough comprises a pond and its fringing non-flooded wetlands, the areal extents of which changed during the season as the pond expanded and contracted. Slough storage was rapidly replenished by the snow and ice melt in the slough and by the meltwater input through overland flow from the uplands. During summer, rainfall was the main source of water supply to the experimental slough, and evaporation exceeded water yield to the groundwater system. Water balance allows a contrast of hydrological conditions between years, with the drier years producing storage deficit for the slough, and wet summers producing a surplus.

Ephemeral Ponds: Are They the Dominant Source of Depression-Focused Groundwater Recharge?

Article

Full-text available

Mar 2020
WATER RESOUR RES

Depression‐focused recharge is a concept proposed to explain groundwater recharge in the prairie regions of North America. Topographic depressions in this hummocky landscape collect blowing snow and snowmelt, and occasional runoff during rainfall events. Wetland ponds that form in these depressions lose water to evaporation and infiltration. Some of this infiltration contributes to groundwater recharge, both to shallow aquifers in the weathered near‐surface, and to underlying confined intertill aquifers. Here we focus on understanding recharge to the confined aquifers, which supply water for farms and rural communities. The isotopic composition of water in these aquifers shows little or no evaporative enrichment and is inconsistent with the average isotopic composition of the ponds. This observation appears to contradict the depression‐focused recharge model. In this field study, we examine the isotopic composition of diverse types of wetland ponds and groundwater at the St. Denis National Wildlife Area, Saskatchewan, Canada. We use hydraulic head data to identify potential recharge and discharge ponds. Water in permanent recharge ponds that do not dry out every year have distinctly different isotopic signatures from the aquifers, suggesting that they cannot be the dominant source of recharge. Water in ephemeral recharge ponds, which are small and dry out quickly, have isotopic signatures identical to those of aquifers. We propose that ephemeral recharge ponds are the dominant source of depression‐focused groundwater recharge in the prairies. We discuss why permanent recharge ponds may not be the main source of groundwater recharge and summarize our findings in a revised conceptual model.

A physically based model for groundwater-pond interactions in the Canadian Prairies

Thesis

Full-text available

Jul 2014

Raphaël Nussbaumer

The Prairie Pothole Region (PPR) is a critical region in Canada because of its crucial role in agricultural production. The area is highly vulnerable to costly floods and droughts, and climate change impacts are likely to be highly damaging. The prairies are relatively flat, seasonally frozen, and semi-arid. The landscape is covered with ponds of varying sizes and with varying temporal persistence, and these ponds interact with shallow groundwater. We have developed a good qualitative understanding of the hydrological behaviour of prairie potholes, through several decades of research. However, accurately quantifying the processes is critical to predicting the system response under any given scenario, and this has proved a major challenge. There is a need for basic research combining numerical models with field observations to develop improved process model, which ultimately will feed into improved predictive tools. This study seeks to apply a physically based model to field site in the PPR where extensive previous research has been undertaken. The fully distributed hydrological model ParFlow (PF), coupled with the Community Land Model (CLM) is used. The objective is to test the ability of this model to reproduce the observed system behaviour. In particular, the processes that need to be simulated include: pond-groundwater interactions; coupled saturated-unsaturated flow in the fractured till, where evapotranspiration and capillarity cause significant groundwater flow reversals and upward flows in the unsaturated zone; and finally cold season processes, in particular snow accumulation and melt, infiltration into and runoff over frozen soils. The results from simulations carried out in this study emphasised the dominant control of the decrease of hydraulic conductivity with depth on pond connectivity. The model successfully simulated the water input regime with the winter accumulation of snow and the rapid snowmelt. Major limitations of the model include the impossibility to simulate runoff and the unvariant behaviour of land cover. Snow/ice processes (freezing, thawing, sublimation etc) were successfully implemented in the model yet some issues remain: large ice deposits can be seen in the vegetated surface, the soil hardly freezes, and snow and ponded water coexist.

Long-term changes in pond permanence, size, and salinity in Prairie Pothole Region wetlands: The role of groundwater-pond interaction

Article

Full-text available

Jun 2018

Study Region: Cottonwood Lake area wetlands, North Dakota, U.S.A. Study Focus: Fluctuations in pond permanence, size, and salinity are key features of prairie-pothole wetlands that provide a variety of wetland habitats for waterfowl in the northern prairie of North America. Observation of water-level and salinity fluctuations in a semi-permanent wetland pond over a 20-year period, included periods when the wetland occasionally was dry, as well as wetter years when the pond depth and surface extent doubled while volume increased 10 times. New hydrological insights for the study region: Compared to all other measured budget components, groundwater flow into the pond often contributed the least water (8–28 percent) but the largest amount (>90 percent) of specific solutes to the water and solute budgets of the pond. In drier years flow from the pond into groundwater represented > 10 percent of water loss, and in 1992 was approximately equal to evapotranspiration loss. Also during the drier years, export of calcium, magnesium, sodium, potassium, chloride, and sulfate by flow from the pond to groundwater was substantial compared with previous or subsequent years, a process that would have been undetected if groundwater flux had been calculated as a net value. Independent quantification of water and solute gains and losses were essential to understand controls on water-level and salinity fluctuations in the pond in response to variable climate conditions.

An improved representation of geographically isolated wetlands in a watershed-scale hydrologic model: An Improved Representation of Geographically Isolated Wetlands

Article

May 2016

Geographically isolated wetlands (GIWs), defined as wetlands surrounded by uplands, provide an array of ecosystem goods and services. Within the United States, federal regulatory protections for GIWs are contingent, in part, on the quantification of their singular or aggregate effects on the hydrological, biological, or chemical integrity of waterways regulated by the Clean Water Act (CWA). However, limited tools are available to assess the downgradient effects of GIWs. We constructed a Soil and Water Assessment Tool (SWAT) model with improved representations of GIW hydrologic processes for the approximately 1700km² Pipestem Creek watershed in the Prairie Pothole Region of North Dakota, USA. We then executed a series of novel modifications on the Pipestem Creek SWAT model. We (1) redefined the model's hydrologic response unit spatial boundaries to conform to mapped GIWs and associated watershed boundaries, (2) constructed a series of new model input files to direct the simulation of GIW fill-spill hydrology and upland flows to GIWs, and (3) modified the model source code to facilitate use of the new SWAT input files and improve GIW water balance simulations. We then calibrated and verified our modified SWAT model at a daily time step from 2009 through 2013. Simulation results indicated good predictive power (the maximum Nash-Sutcliffe Efficiency statistic was 0.86) and an acceptable range of uncertainty (measured using the Sequential Uncertainty Fitting v.2 uncertainty statistics). Simulation results additionally indicated good model performance with respect to GIW water balance simulations based on literature-based descriptions of regional GIW hydrologic behaviour. Our modified SWAT model represents a critical step in advancing scientific understandings of the watershed-scale hydrologic effects of GIWs and provides a novel method for future assessments in different watersheds and physiographic regions.

Influence of shallow groundwater-surface water interactions on the hydrological connectivity and water budget of a wetland complex: Shallow Groundwater-surface Water Interactions in a Wetland Complex

Article

Jun 2015
HYDROL PROCESS

Linkages between the controls on surface storage and catchment streamflow response were examined in a wetland dominated basin in the Canadian Prairie Pothole region. Snowmelt, surface storage, water table elevation, atmospheric fluxes, and streamflow were monitored during spring snowmelt and summer in a 1 km2 sub-catchment containing a semi-permanent pond complex connected via an intermittent stream. Snow accumulation in the basin in spring of the 2013 study year was the largest in the 24-year record. Rainfall totals in 2013 were close to the long term average, though June was an anomalously wet month. The water budget of the pond complex indicates that there was a significant subsurface contribution to surface storage. Activation of an effective transmission zone occurred between uplands and the stream network where the water table was located near the ground surface, which allowed significant lateral movement of subsurface water into the stream network. This was also important for maintaining and re-establishing surface connectivity and streamflow during rainfall events. The observed period of surface-water connectivity was one of the longest on record in the catchment due to unusually wet conditions; nevertheless, the results of this study have implications for how contributing area and runoff should be considered in monitoring and modelling studies in the region, as inclusion of more frequent and varied runoff processes will be essential to understanding changing streamflow regimes. This article is protected by copyright. All rights reserved.

Towards an improved land surface scheme for prairie landscapes

Article

Apr 2014
J HYDROL

The prairie region of Canada and the United States is characterized by millions of small depressions of glacial origin called prairie potholes. The transfer of surface runoff in this landscape is mainly through a “fill and spill” mechanism among neighboring potholes. While non-contributing areas, that is small internally drained basins, are common on this landscape, during wet periods these areas can become hydrologically connected to larger regional drainage systems. Accurate prediction of prairie surface runoff generation and streamflow thus requires realistic representation of the dynamic threshold-mediated nature of these contributing areas. This paper presents a new prairie surface runoff generation algorithm for land surface schemes and large scale hydrological models that conceptualizes a hydrologic unit as a combination of variable and interacting storage elements. The proposed surface runoff generation algorithm uses a probability density function to represent the spatial variation of pothole storages and assumes a unique relationship between storage and the fractional contributing area for runoff (and hence amount of direct runoff generated) within a grid cell. In this paper the parameters that define this relationship are obtained by calibration against streamflow. The model was compared to an existing hydrology-land surface scheme (HLSS) applied to a typical Canadian prairie catchment, the Assiniboine River. The existing configuration is based on the Canadian Land Surface Scheme (CLASS) and WATROF (a physically-based overland and interflow scheme). The new configuration consists of CLASS coupled with the new PDMROF model. Results showed that the proposed surface runoff generation algorithm performed better at simulating streamflow, and appears to capture the dynamic nature of contributing areas in an effective and parsimonious manner. A pilot evaluation based on 1 m LiDAR data from a small (10 km2) experimental area suggests that the shape of the modeled storage-contributing area relationship is broadly consistent with that inferred from terrain analysis, under certain simplifying assumptions. The direct identification of storage–runoff parameters from terrain analysis is an outstanding challenge, and a promising area for future research.

Quantifying the wetland water balance: A new isotope-based approach that includes precipitation and infiltration

Article

Dec 2018
J HYDROL

Stable isotopes have been used to quantify lake and wetland pond water loss to evaporation by applying the modified Craig and Gordon (1965) model. This model and its derivatives employ simplifying assumptions that ignore the additions of precipitation and infiltration outputs and assume evaporation is the only loss term over the prediction period. Here we develop a coupled water and isotope mass-balance model to account for precipitation additions. Our model uses physical and isotopic observations to quantify pond evaporation and infiltration losses over the ice-free period. We tested and applied the model to four wetland ponds at the St Denis National Wildlife Research Area, Saskatchewan Canada, where we have long-term datasets. Modeled infiltration rates from the ponds ranged between 0.99 and 9.2 mm/d and open water evaporation rates ranged between 0.88 and 2.8 mm/d. Both were consistent with independent estimates. Infiltration amounts were highest in the ephemeral ponds (that dry out within days or weeks of the spring melt period). In these ponds, infiltration exceeded evaporation. In permanent ponds, that is ponds that do not dry out; evaporation exceeded infiltration. Evaporation amounts were most substantial for permanent ponds that were not sheltered by topography or riparian vegetation. Overall, our coupled water and isotope mass-balance model combined with physical and isotope observations was able to quantify the spatially and temporally variable evaporation and infiltration fluxes within and between ponds.

On the changes in long term streamflow regimes in the Prairies

Article

Full-text available

May 2014

Climate change/variability accompanied by anthropogenic activities can alter the runoff response of landscapes. In this study we investigate the integrated impacts of precipitation change/variability and landscape changes, specifically wetland drainage practices, on streamflow regimes in wetland dominated landscapes in the Assiniboine and Saskatchewan River Basins of the North American Prairies. Precipitation and streamflow metrics were examined for gradual (trend type) and abrupt (shift type) changes using the modified Mann-Kendall trend test and a Bayesian change point detection methodology. Results of statistical analyses indicate that precipitation metrics did not experience statistically significant increasing or decreasing changes and there was no statistical evidence of streamflow regime change over the study area except for one of the smaller watersheds. The absence of widespread streamflow and precipitation change suggests that wetland drainage did not lead to detectable changes in streamflow metrics over most of the Canadian portion of the Prairies from 1967 to 2007.

Wet–dry cycles influence methylmercury concentrations in water in seasonal prairie wetland ponds

Article

Full-text available

Jun 2023

Methylmercury concentrations [MeHg] in whole water were measured in 28 prairie wetland ponds in central Saskatchewan between 2006 and 2012. Ponds fell into four land use categories (established grass, recent grass, traditional cultivated, and certified organic cultivated) and two water level patterns (“Mainly Wet” ponds stayed wet at least until October and “Mainly Dry” ponds dried up each summer). Despite similar atmospheric Hg deposition, average [MeHg] and proportion of total Hg that was MeHg (%MeHg) were higher in water from ponds surrounded with established grass or organic farming; this trend may be driven by high [MeHg] at one Organic site. A stronger relationship was observed with water level patterns. Average [MeHg] and %MeHg were significantly higher in Mainly Wet ponds compared to Mainly Dry ponds. Higher [MeHg] in Mainly Wet ponds were correlated with much higher dissolved organic carbon (DOC) and sulfate (SO4⁻²) concentrations and higher specific UV absorbance of DOC. We suggest that prairie wetland ponds may not fit the accepted paradigm that wetlands with high [SO4⁻²] show inhibition of Hg methylation. Our work suggests controls such as the chemical nature of DOC or redox fluctuations in hydrologically dynamic systems may be important in determining net [MeHg] in these sites.

Proceedings of the fifth Prairie Conservation and Endangered Species Workshop : February 1998 at the Saskatoon Inn, Saskatoon, SK

Book

Jan 1998

Assessing runoff sensitivity of North American Prairie Pothole Region basins to wetland drainage using a basin classification–based virtual modeling approach

Preprint

Full-text available

May 2022

Wetland drainage has been pervasive in the North American Prairie Pothole Region. There is strong evidence that this drainage increases hydrological connectivity of previously isolated wetlands and, in turn, streamflow response to precipitation. It can be hard to disentangle the role of climate from the influence of wetland drainage in observed streamflow records. In this study, a basin classification-based virtual modelling approach is described that can isolate these effects on runoff regimes. Three knowledge gaps were addressed. First, it was determined that the spatial pattern in which wetlands are drained has little influence on how much the runoff regime was altered. Second, no threshold could be identified below which wetland drainage has no effect on the streamflow regime, with drainage thresholds as low as 10 % by area were evaluated. Third, wetter regions were less sensitive to drainage as they tend to be better hydrologically connected even in the absence of drainage. Low flows were the least affected by drainage. During extremely wet years, runoff depths could double as the result of complete wetland removal. Simulated median annual runoff depths were the most responsive, potentially tripling under typical conditions with the high rates of wetland drainage. As storage capacity is removed from the landscape through wetland drainage, the size of the storage deficit of median years begins to decrease and to converge on those of the extreme wet years. Model simulations of flood frequency suggest that because of these changes in antecedent conditions, precipitation that once could generate a median event with wetland drainage can generate what would have been a maximum event without wetland drainage. The advantage of the basin classification-based virtual modelling approach employed here is that it simulated a long period that included a wide variety of precipitation and antecedent storage conditions across a diversity of wetland complexes. This has allowed seemingly disparate results of past research to be put into context and finds that conflicting results are often only because of differences in spatial scale and temporal scope of investigation. A conceptual framework is provided that shows, in general, how annual runoff in different climatic and drainage situations will likely respond to wetland drainage in the Prairie Pothole Region.

Assessing hydrological sensitivity of grassland basins in the Canadian Prairies to climate using a basin classification–based virtual modelling approach

Preprint

Full-text available

May 2021

Significant challenges from changes in climate and land-use face sustainable water use in the Canadian Prairies ecozone. The region has experienced significant warming since the mid 20th Century, and continued warming of an additional 2 °C by 2050 is expected. This paper aims to enhance understanding of climate controls on Prairie basin hydrology through numerical model experiments. It approaches this by developing a basin classification–based virtual modeling framework for a portion of the Prairie region, and applying the modelling framework to investigate the hydrological sensitivity of one Prairie basin class (High Elevation Grasslands) to changes in climate. High Elevation Grasslands dominate much of central and southern Alberta and parts of southwestern Saskatchewan with outliers in eastern Saskatchewan and western Manitoba. The experiments revealed that High Elevation Grasslands snowpacks are highly sensitive to changes in climate, but that this varies geographically. Spring maximum snow water equivalent in grasslands decreases 8% per degree °C of warming. Climate scenario simulations indicated a 2 °C increase in temperature requires at least an increase of 20% in mean annual precipitation for there to be enough additional snowfall to compensate for enhanced melt losses. The sensitivity in runoff is less linear and varies substantially across the study domain; simulations using 6 °C of warming and a 30% increase in mean annual precipitation yields simulated decreases in annual runoff of 40% in climates of the western Prairie but 55% increases in climates of eastern portions. These results can be used to identify those areas of the region that are most sensitive to climate change, and highlight focus areas for monitoring and adaptation. The results also demonstrate how a basin classification–based virtual modeling framework can be applied to evaluate regional scale impacts of climate change with relatively high spatial resolution, in a robust, effective and efficient manner.

Quantifying the effects of Prairie depressional storage complexes on drainage basin connectivity

Article

Feb 2021
J HYDROL

Runoff in many locations within the Canadian Prairies is dominated by intermittent fill-and-spill between depressions. As a result, many basins have varying fractions of their areas connected to their outlets, due to changing depressional storage. The objective of this research is to determine the causes of the relationships between water storage and the connected fraction of depression-dominated Prairie basins. It is hypothesized that the shapes of the relationship curves are influenced by both the spatial and frequency distributions of depressional storage. Three sets of numerical experiments are presented to test the hypothesis. The first set of experiments demonstrates that where the number of depressions is small, their size and spatial distributions are important in controlling the relationship between the volume of depressional storage and the connected fraction of a basin. As the number of depressions is increased, the areal fractions of the largest depressions decrease, which reduces the importance of the spatial distribution of depressions. The second set of experiments demonstrates that the curve enveloping the connected fraction of a basin can be derived from the frequency distribution of depression areas, and scaling relationships between the area, volume and catchment area of the depressions, when the area of the largest depression is no greater than approximately 5% of the total. The third set of experiments demonstrates that the presence of a single large depression can strongly influence the relationship between the depressional storage and the connected fraction of a basin, depending on the relative size of the large depression, and its location within the basin. A single depression containing 30% of the total depressional area located near the outlet was shown to cause a basin to be nearly endorheic. A similar depression near the top of a basin was demonstrated not to fill and was therefore unable to contribute flows. The implications of the findings for developing hydrological models of large Prairie drainage basins are discussed.

A classification scheme to determine wildfires from the satellite record in the cool grasslands of southern Canada: considerations for fire occurrence modelling and warning criteria

Article

Full-text available

Dec 2020
NAT HAZARD EARTH SYS

Daily polar-orbiting satellite MODIS thermal detections since 2002 were used as the baseline for quantifying wildfire activity in the mixed grass and agricultural lands of southernmost central Canada. This satellite thermal detection record includes both the responsible use of fire (e.g. for clearing crop residues, grassland ecosystem management, and traditional burning) and wildfires in grasslands and agricultural lands that pose a risk to communities and other values. A database of known wildfire evacuations and fires otherwise requiring suppression assistance from provincial forest fire agencies was used to train a model that classified satellite fire detections based on weather, seasonality, and other environmental conditions. A separate dataset of high resolution (Landsat 8 thermal anomalies) of responsible agricultural fire use (e.g. crop residue burning) was collected and used to train the classification model to the converse. Key common attributes of wildfires in the region included occurrence on or before the first week of May with high rates of grass curing, wind speeds over 30 km h−1, relative humidity values typically below 40 %, and fires that are detected in the mid-afternoon or evening. Overall, grassland wildfire is found to be restricted to a small number of days per year, allowing for the future development of public awareness and warning systems targeted to the identified subset of weather and phenological conditions.

Conceptualizing Cascading Effects of Resilience in Human-Water Systems

Chapter

Full-text available

Dec 2020

People and water interact over time and across space as coupled systems. Investigating the resilience of such coupling should take a multi-systemic approach to address not only the resilience in different human and water systems, but also the interrelationship between their resilience processes. Based on the three framings of resilience in the coupled human-water context (i.e. social resilience, hydrological resilience, and socio-hydrological resilience), a conceptual framework is proposed for understanding the cascading effects of resilience along a chain of resilience change across systems and scales. We use a case example from a drainage basin in the Canadian Prairies to exemplify this framework and demonstrate how a change in the resilience of one system can exert an impact on the resilience of another, in socio-hydrological systems that are under the influence of both human activities and climate change.

A multi-objective calibration approach using in-situ soil moisture data for improved hydrological simulation of the Prairies

Article

Jan 2020

Traditionally, hydrological models are only calibrated to reproduce streamflow regime without considering other hydrological state variables, such as soil moisture and evapotranspiration. Limited studies have been performed on constraining the model parameters, despite the fact that the presence of large number of parameters may provide large degree of freedom, resulting in equifinality and poor model performance. In this study, a multi-objective optimization approach is adopted, and both streamflow and soil moisture data are calibrated simultaneously for an experimental study basin in the Saskatchewan Prairies in western Canada. The results of this study show that the multi-objective calibration improves model fidelity compared to the single objective calibration. Moreover, the study demonstrates that, single objective calibration performed against only streamflow can fairly mimic the streamflow hydrograph but does not yield realistic estimation of other fluxes such as evapotranspiration and soil moisture (especially in deeper soil layers).

Meteorological, soil moisture, surface water, and groundwater data from the St. Denis National Wildlife Area, Saskatchewan, Canada

Article

Full-text available

Apr 2019

The St. Denis National Wildlife Area is located in the seasonally frozen and semi-arid Canadian Prairies, close to Saskatoon, Saskatchewan. The site has a hummocky terrain and is underlain by clay-rich glacial tills. Though the site is only 4 km² it contains hundreds of wetlands containing ponds which range in size, in permanence (from ephemeral to permanent), and in their interactions with groundwater (recharge and discharge ponds are present). The site was established as a research area in 1968 and has long-term records of hydrological observations, including meteorological, snow, soil moisture, surface water (ponds) and groundwater data. Some records, notably the pond level and chemistry data, span the period 1968 to present. Other datasets, notably water level observations from networks of piezometers, have been collected sporadically at different locations and times. Some datasets are collected manually on an annual basis, including pond surveys and snow surveys. Meteorological data have been collected by automatic weather stations since 1989 and have been maintained and upgraded over time, with a flux tower added to the site in 2011. Automatically logged soil moisture profiles and collocated piezometers have been running since 2013. A lidar survey from 2005 provides a 1 m resolution digital elevation map (DEM) of the site and surrounding landscape. The compiled data are available at https://doi.org/10.20383/101.0115 (Bam et al., 2018).

Impact of climate variability and wetland drainage on watershed response in depression dominated landscapes

Article

Full-text available

Nov 2017

Eghbal Ehsanzadeh

This study investigates changes in runoff production behavior which may have occurred due to climate change/variability and/or as a result of draining of wetlands over Canadian portion of North American Prairies. The study uses statistical methods to quantify changes in precipitation/runoff over various spatial and temporal scales. The major results indicate dominated upward trends in some runoff metrics over some Prairie watersheds whereas there is no concrete evidence of statistically significant precipitation trends during the observation period. The observed changes in runoff response, therefore, are interpreted to represent possible effects of intensive wetland drainage. The remaining unchanged metrics over the majority of tested watersheds are interpreted to be due to varying progressive land use/cover disturbances which may have conflicting impacts on watershed response in the Prairies. The absence of significant changes in precipitation and observed changes in hydrology of some parts of the study area may support the narrative that loss of wetlands has led to increased flood risks in this area. However, information on major land cover indices like intact forests, agricultural land, urban areas within the study area, and landscape best management practices would be necessary to fully comprehend land use change and its impact on the Prairie’s hydrology.

Applying isotope geochemistry to identify mechanisms regulating the aquatic-terrestrial carbon and nitrogen dynamics across scales in a moraine landscape

Thesis

May 2017

Kai Nitzsche

In dieser Studie wurden stabile Isotopenverhältnisse genutzt um die Mechanismen der aquatisch-terrestrischen C – und N-Dynamiken über verschiedene Skalenebenen hinweg in der Moränenlandschaft von Nordostdeutschland zu identifizieren; einer Landschaft, die stark landwirtschaftlich genutzt wird und in der es eine Vielzahl von kleinen Wasserkörpern (Sölle) gibt. Auf der regionalen Landschaftsskala spiegeln d13C-Isotopenkarten des org. Materials in Oberböden und von Pflanzenblättern eines 38.2 km2 großen Gebietes den Eintrag von org. Material von C3-Pflanzen, deren Wassernutzungseffizienz im org. Material des Bodens eingeprägt wurde, sowie den Eintrag von Mais (C4-Pflanze), wider. Die d15N-Isotopenkarte des org. Materials in Böden weist verschiedene Düngepraktiken hin. Auf der regionalen Sollskala deuten die d13C- und d15N-Isotopenwerte von Oberflächensedimenten von 51 Söllen auf kürzliche Einträge des org. Materials und Bewirtschaftungseffekte im Einzugsgebiet hin. Tiefere Sedimente sind durch die Ablagerung org. Materials von terrestrischen Pflanzen sowie dessen Umsetzungsgrad geprägt in Abhängigkeit von der Wasserführung. Auf der Transekt-Skala, d.h. entlang von Transekten von Erosions- zu Depositionsgebieten im Einzugsgebiet eines Solls, beeinflussen Erosion, Pflanzenproduktion, mikrobielle Umsetzung und Gülledüngung verschiedene Fraktionen des org. Materials. Auf der Aggregat-Skalenebene sind die Art und der Anteil spezifischer organo-mineral Assoziationen entlang des Transekts variabel. Bodenpartikel vom Feld und hereinwachsende Makrophyten sind die Quellen des org. Materials in Sedimenten. Diese Studie hat erfolgreich stabile Isotopenverhältnisse zur Identifikation von Mechanismen der C- und N-Dynamik auf individuellen Skalenebenen angewendet. Kleine Inlandwasserkörper sind Schlüsselelemente für die C- und N-Dynamik in landwirtschaftlich genutzten Moränenlandschaften.

Land-use and hydroperiod affect kettle hole sediment carbon and nitrogen biogeochemistry

Article

Jan 2017
SCI TOTAL ENVIRON

Kettle holes are glaciofluvially created depressional wetlands that collect organic matter (OM) and nutrients from their surrounding catchment. Kettle holes mostly undergo pronounced wet-dry cycles. Fluctuations in water table, land-use, and management can affect sediment biogeochemical transformations and perhaps threaten the carbon stocks of these unique ecosystems. We investigated sediment and water of 51 kettle holes in NE Germany that differ in hydroperiod (i.e. the duration of the wet period of a kettle hole) and land-use. Our objectives were 1) to test if hydroperiod and land management were imprinted on the isotopic values (delta C-13, delta N-15) and C:N ratios of the sediment OM, and 2) to characterize water loss dynamics and kettle hole-groundwater connectivity by measuring the stable 6150 and BD isotope values of kettle hole water over several years. We found the uppermost sediment layer reflected recent OM inputs and short-term processes in the catchment, including land-use and management effects. Deeper sediments recorded the degree to which OM is processed within the kettle hole related to the hydroperiod. We see clear indications for the effects of wet-dry cycles for all kettle holes, which can lead to the encroachment of terrestrial plants. We found that the magnitude of evaporation depended on the year, season, and land-use type, that kettle holes are temporarily coupled to shallow ground water, and, as such, kettle holes are described best as partially-closed to open systems.

Land-use and hydroperiod affect kettle hole sediment carbon and nitrogen biogeochemistry

Article

Jan 2017

Water circulation in the moraine ponds of northern Poland

Article

Full-text available

Jun 2017
HYDROBIOLOGIA

The landscape of northern Poland is characterised by a very large number of ponds. Traditionally it has been assumed that their hydrology is determined by precipitation and evaporation, and that they are isolated from the adjacent river network. Recent studies, however, have shown that ponds contribute to river runoff for at least part of the year. Their existence is therefore additionally based on fluvial and underground water sources. In order to establish the principles of water circulation in typical ponds, we selected 14 ponds with seasonally intermittent streams. We measured water levels in these ponds and flows in the river segments that connect them. We also determined subsurface exchange fluxes from the water balance equation. Our results demonstrated that the hydrological functions of the ponds varied throughout the year and depended on the level of water storage in the pond’s catchment. When the level of retention in the pond’s catchment is low, the pond becomes a water body without surface outflow and a drainage base for groundwater. As the level of retention in the catchment rises, ponds develop surface outflows and reconnect with the river network. At this point, their main function becomes retention of water originating from subsurface and surface inflows. Any surplus water may be fed to underground or surface waters.

Extending current models of surface water flow to include explicit recognition of depressions and of connectivity between depressions

Research

Full-text available

Apr 2016

A very early article on an alternative approach to removing pits from digital elevation models that was implemented in the LandMapR software as early as 1994. This article was submitted to, and accepted by PERS in 2002 but the first author never followed up with final publication.

Hydrology and water resources

Article

Full-text available

Jan 2005

Hydrological Response of a Patchy High Arctic Wetland

Article

Aug 2000

High Arctic patchy wetlands are ecological oases in a polar desert environment and are vulnerable to climatic warming. At present, understanding of their responses to external factors (climate and terrain) is limited. This study examines a wetland located in a topographic depression maintained by seasonal snowmelt, ground ice melt and lateral inflows. The wetland is located on Cornwallis Island, Nunavut, Canada. Hydrological, climatological and soil observations were made over several summers with different weather conditions. The summers of 1996 and 1997 were cool and wet but the summer of 1998 was warm and dry. The melt in 1996 was rapid due to rain on snow events and only lasted six days. Deeper snow in 1997 prolonged the melt season to 18 days. A shallow snowcover in 1998 and early melt depleted the snow by early June. Surface, groundwater and storage fluctuations in the wetland were dictated by snowmelt, rainfall, evaporation loss from the wetland and lateral inputs which in turn were controlled by the melting of the late-lying snow storage in the catchment. Soil factors influence the spatial variations in ground thaw which affects the surface and subsurface flow. Streamflow response of the wetland reflects a nival regime and augmentation of streamflow thoughout the summer season in all three years is supported by multiple water sources: ground ice melt and suprapermafrost water from a large late-lying snowpack. Overall, this study suggests that the survival of some patchy wetlands depends on their interaction with the surrounding basin, with a dependency probably being more important during warm and dry seasons.

Prediction of snowmelt derived streamflow in a wetland dominated prairie basin hess-14-991-2010

Data

Full-text available

Sep 2015

Prediction of snowmelt derived streamflow in a wetland dominated prairie basin hess-14-991-2010

Data

Full-text available

Sep 2015

Arctic contaminants: five years of progress in understanding sources, occurrence and pathways

Conference Paper

Full-text available

Jan 1996

Prairie Wetland Soils: Gleysolic and Organic

Article

Full-text available

Angela Bedard-Haughn

Gleysolic and Organic soils are collectively referred to as "wetland soils". They are found in wet low-lying or level landscape positions. Gleysolic soils are found throughout the agricultural Prairies, in association with Chernozemic and Luvisolic soils. In semi-arid regions, they are frequently tilled in dry years and can be very productive due to their relatively high levels of soil moisture and nutrients. In the Prairie Provinces, Organic soils tend to be mostly associated with the Boreal transition zones at the northern and eastern perimeter of the Prairies. With proper management, these can also provide productive agricultural land, particularly for forages.

Greenhouse gas cycling in experimental boreal reservoirs

Article

Jason J. Venkiteswaran

Reconstructing sixty year (1950-2009) daily soil moisture over the Canadian Prairies using the Variable Infiltration Capacity model

Article

Full-text available

Jan 2013

The Variable Infiltration Capacity (VIC) land surface macroscale hydrology model was used to reconstruct 60 years (1950-2009) of daily soil moisture values for three soil layers (0–20 cm, 20–100 cm, and 0–100 cm) over the three Canadian Prairie Provinces with a total area of 1,964,000 km2. VIC was applied over a grid of 4,393 points with a resolution of 0.25° × 0.25°, and was driven by observed daily maximum and minimum air temperature and precipitation from 1,167 meteorological stations. The model was first calibrated using observed hydrographs from seven catchments with drainage areas varying from 3,750 to 7,870 km2. Special attention was given to modelling of rainfall-runoff processes over the non-contributing drainage area of the Prairies. VIC was then validated over these seven catchments at different periods and over an additional five catchments with drainage areas ranging from 36,500 to 131,000 km2. An estimation procedure to determine model parameters was developed and applied to catchments where hydrographs are not available for the standard calibration process. In situ soil moisture measurements from six Alberta sites were also used for model validation. VIC performed well over both calibration and validation catchments. The results clearly demonstrate that incorporating non-contributing drainage areas into runoff calculations could substantially improve the ability of VIC to simulate surface and sub-surface runoff in regions where poor drainage network development is a dominant feature of drainage basins. The VIC reconstructed 60–year average of the soil moisture in the top 1 m shows some expected climatological features of the Prairies. For example, the reconstructed soil moisture climatology portrays the dry Palliser Triangle region and the Prairie Dry Belt in the southern Prairies. The VIC simulated soil moisture was used to calculate the daily Soil Moisture Anomaly Percentage Index (SMAPI) for the three soil layers; SMAPI can be used as an index of agricultural drought severity taking into account climatology. The value of the calculated SMAPI in quantifying and documenting prairie drought events is demonstrated through an intensive examination of the April 2002 drought case.

Climatic and hydrologic processes leading to wetland losses in Yellowstone National Park, USA

Article

Mar 2014
J HYDROL

Advances in wetland hydrology: the Canadian contribution over 75 years

Article

Nov 2023

Assessing hydrological sensitivity of grassland basins in the Canadian Prairies to climate using a basin classification-based virtual modelling approach

Article

Full-text available

Apr 2022
HESS

Significant challenges from changes in climate and land use face sustainable water use in the Canadian Prairies ecozone. The region has experienced significant warming since the mid-20th century, and continued warming of an additional 2 ∘C by 2050 is expected. This paper aims to enhance understanding of climate controls on Prairie basin hydrology through numerical model experiments. It approaches this by developing a basin-classification-based virtual modelling framework for a portion of the Prairie region and applying the modelling framework to investigate the hydrological sensitivity of one Prairie basin class (High Elevation Grasslands) to changes in climate. High Elevation Grasslands dominate much of central and southern Alberta and parts of south-western Saskatchewan, with outliers in eastern Saskatchewan and western Manitoba. The experiments revealed that High Elevation Grassland snowpacks are highly sensitive to changes in climate but that this varies geographically. Spring maximum snow water equivalent in grasslands decreases 8 % ∘C−1 of warming. Climate scenario simulations indicated that a 2 ∘C increase in temperature requires at least an increase of 20 % in mean annual precipitation for there to be enough additional snowfall to compensate for enhanced melt losses. The sensitivity in runoff is less linear and varies substantially across the study domain: simulations using 6 ∘C of warming, and a 30 % increase in mean annual precipitation yields simulated decreases in annual runoff of 40 % in climates of the western Prairie but 55 % increases in climates of eastern portions. These results can be used to identify those areas of the region that are most sensitive to climate change and highlight focus areas for monitoring and adaptation. The results also demonstrate how a basin classification-based virtual modelling framework can be applied to evaluate regional-scale impacts of climate change with relatively high spatial resolution in a robust, effective and efficient manner.

What conditions favor the influence of seasonally frozen ground on hydrological partitioning? A systematic review

Article

Full-text available

Apr 2021
ENVIRON RES LETT

The influence of seasonally frozen ground (SFG) on water, energy, and solute fluxes is important in cold climate regions. The hydrological role of permafrost is now being actively researched, but the influence of SFG has received less attention. Intuitively, SFG restricts (snowmelt) infiltration, thereby enhancing surface runoff and decreasing soil water replenishment and groundwater recharge. However, the reported hydrological effects of SFG remain contradictory and appear to be highly site- and event-specific. There is a clear knowledge gap concerning under what physiographical and climate conditions SFG is more likely to influence hydrological fluxes. We addressed this knowledge gap by systematically reviewing published work examining the role of SFG in hydrological partitioning. We collected data on environmental variables influencing the SFG regime across different climates, land covers, and measurement scales, along with the main conclusion about the SFG influence on the studied hydrological flux. The compiled dataset allowed us to draw conclusions that extended beyond individual site investigations. Our key findings were: (1) an obvious hydrological influence of SFG at small-scale, but a more variable hydrological response with increasing scale of measurement, and (2) indication that cold climate with deep snow, and forest land cover may be related to reduced importance of SFG in hydrological partitioning. It is thus increasingly important to understand the hydrological repercussions of SFG in a warming climate, where permafrost is transitioning to seasonally frozen conditions.

Development of post-disturbance vegetation in prairie wetlands

Chapter

Jan 2021

Arnold G. van der Valk

It has long been recognized that plants are adapted to specific environmental conditions (e.g., soil moisture, soil chemistry, air temperature, and light levels) and that the distribution of plants varies along environmental gradients producing coenoclines (community gradients found along environmental gradients). Freshwater wetlands such as prairie potholes are ideal systems for studying coenoclines because their coenoclines are short and the main factor controlling the distribution of species along them is water depth. These wetlands undergo oscillatory waterlevel fluctuations that can at times result in destruction of most of their vegetation. Such disturbances provide an opportunity to study the development of post-disturbance coenoclines. This chapter reviews what is known about post-disturbance coenocline development in prairie wetlands, addresses the development of new coenoclines when pre- and post-disturbance water levels are the same or different, and reports on some models of coenocline development.

Depressional Wetlands Affect Watershed Hydrological, Biogeochemical, and Ecological Functions

Article

Feb 2018

Prediction of snowmelt derived streamflow in a wetland dominated prairie basin

Article

Full-text available

Feb 2010
HESSD

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 Regions Hydrological Modelling platform (CRHM) is an assembly system that can be used to set up physically based, flexible, object oriented models. CRHM was used to create a prairie hydrological model for the externally drained Smith Creek Research Basin (~400 km2), east-central Saskatchewan. Physically based modules were sequentially linked in CRHM to simulate snow processes, frozen soils, variable contributing area and wetland storage and runoff generation. Five "representative basins" (RBs) were used and each was divided into seven hydrological response units (HRUs): fallow, stubble, grassland, river channel, open water, woodland, and wetland as derived from a supervised classification of SPOT 5 imagery. Two types of modelling approaches calibrated and uncalibrated, were set up for 2007/08 and 2008/09 simulation periods. For the calibrated modelling, only the surface depression capacity of upland area was calibrated in the 2007/08 simulation period by comparing simulated and observed hydrographs; while other model parameters and all parameters in the uncalibrated modelling were estimated from field observations of soils and vegetation cover, SPOT 5 imagery, and analysis of drainage network and wetland GIS datasets as well as topographic map based and LiDAR DEMs. All the parameters except for the initial soil properties and antecedent wetland storage were kept the same in the 2008/09 simulation period. The model performance in predicting snowpack, soil moisture and streamflow was evaluated and comparisons were made between the calibrated and uncalibrated modelling for both simulation periods. Calibrated and uncalibrated predictions of snow accumulation were very similar and compared fairly well with the distributed field observations for the 2007/08 period with slightly poorer results for the 2008/09 period. Soil moisture content at a point during the early spring was adequately simulated and very comparable between calibrated and uncalibrated results for both simulation periods. The calibrated modelling had somewhat better performance in simulating spring streamflow in both simulation periods, whereas the uncalibrated modelling was still able to capture the streamflow hydrographs with good accuracy. This suggests that prediction of prairie basins without calibration is possible if sufficient data on meteorology, basin landcover and physiography are available.

Modeling of nutrient export and effects of management practices in a cold-climate prairie watershed: Assiniboine River watershed, Canada

Article

Jul 2016
AGR WATER MANAGE

Non-point source pollution due to agricultural activities is an important problem that has been threatening water resources in Canadian prairie watersheds. The development of strategies to prevent nutrient loss depends on the quantification of nutrient mobilization and transport across a watershed. Integrated eco-hydrological models can play an important role in this regard. However, current model applicability to cold-climate Canadian prairie watersheds is limited due to the complex dynamics of nutrient export under the existence of numerous landscape depressions and freeze-thaw cycles. The aim of this study was to evaluate an eco-hydrological model for nutrient export prediction and assess the impacts of management practices for a cold-climate prairie watershed. To achieve the objectives, a new version of the SWAT model called SWAT-PDLD, which combines SWAT and a Probability Distributed Landscape Depressions (PDLD) model, along with a seasonally varying soil erodibility factor, was applied to a Canadian prairie watershed (the Assiniboine River watershed, Saskatchewan, Canada). The PDLD module is used to simulate the effect of the numerous landscape depressions that exist in these watersheds on streamflow, whereas a seasonally varying soil erodibility factor is used to take into account seasonal variation of sediment and nutrient generation due to the cold climate conditions. Model calibration and uncertainty analysis were performed using the Sequential Uncertainty Fitting (SUFI-2). The study shows that the SWAT-PDLD model with seasonally varying soil erodibility simulates the daily nutrient export in a cold prairie watershed satisfactorily as confirmed by both graphical plots and statistical measures. A sensitivity analysis of sub-watershed discretization revealed that the streamflow is relatively insensitive to sub-watershed discretization but it did affect sediment and nutrient export. Importantly, the model shows that both filter strips and cover crops decreased sediment, phosphorous, and nitrogen export, while conservation tillage increased phosphorous export in the study watershed.

Photodegradation of DOC in a shallow prairie wetland: evidence from seasonal changes in DOC optical properties and chemical characteristics (vol 69, pg 263, 2004)

Article

Full-text available

Sep 2005

Wetlands across the Canadian prairies are typically shallow (< 1.0 m) and exhibit high dissolved organic carbon (DOC) concentrations (> 10 mg l(-1)). Studies have shown that DOC in such shallow wetlands is not as reliable an indicator of ultraviolet radiation (UVR) attenuation as it is in clearwater. Changes in DOC character and composition as a result of sunlight exposure might provide a reasonable explanation for this observation. To test this, we investigated seasonal changes in optical and chemical properties in a shallow prairie wetland over a 2-year period. Although DOC concentration increased at least two-fold from spring until fall, DOC specific absorption ( at 350 nm) and fluorescence decreased by 30 and 32%, respectively, for the same period. In both years, seasonal decreases in DOC molecular weight and size ( from measurements of tangential filtration and mass electrospray mass spectrometry) were reflected in concomitant increases in spectral slope. C-13 NMR analysis of DOC isolated on XAD-8 resins revealed a 49% decrease in aromatic moieties when spring values were compared to those in the fall. As well, delta(13)C signatures of this isolated DOC became heavier seasonally. In a short term photodegradation experiment (6 days) we noted a 47% decline in DOC specific absorption coefficients at 350 nm and a 15% increase in spectral slope when water exposed to the total light spectrum was compared to that of a dark control. Taken together, all of these observations were consistent with the occurrence of seasonal DOC photodegradation in shallow prairie wetlands and underlined the importance of this process in shaping DOC character and composition in these hydrologically dynamic systems. Our data also indicates that constant mixing and shallow depths in these wetlands were factors which enhanced DOC photodegradation. Although the high DOC concentrations of prairie wetlands should theoretically protection for their biota, seasonal photodegradation of DOC means that these systems may not be as protected as their high DOC concentrations suggest.

Incorporating landscape depression heterogeneity into the Soil and Water Assessment Tool (SWAT) using a probability distribution

Article

Jun 2016

Modelling the hydrology of North American Prairie watersheds is complicated due to the existence of numerous landscape depressions that vary in storage capacity. The Soil and Water Assessment Tool (SWAT) is a widely applied model for long term hydrological simulations in watersheds dominated by agricultural land uses. However, several studies show that the SWAT model has had limited success in handling prairie watersheds. In past works using SWAT, landscape depression storage heterogeneity has largely been neglected or lumped. In this study, a probability distributed model of depression storage is introduced into the SWAT model to better handle landscape storage heterogeneity. The work utilizes a probability density function to describe the spatial heterogeneity of the landscape depression storages that was developed from topographic characteristics. The integrated SWAT-PDLD model is tested using datasets for two prairie depression dominated watersheds in Canada: the Moose Jaw River watershed, Saskatchewan; and the Assiniboine River watershed, Saskatchewan. Simulation results were compared to observed streamflow using graphical and multiple statistical criterions. Representation of landscape depressions within SWAT using a probability distribution (SWAT-PDLD) provides improved estimations of streamflow for large prairie watersheds in comparison to results using a lumped, single storage approach.

Sediment Export Modeling in Cold-Climate Prairie Watersheds

Article

Jan 2016

Nonpoint source pollution is a critical problem in Canadian prairie watersheds. However, sediment mobilization and export are poorly represented in existing models for these watersheds. The poor representation is partly because the hydrology of the region is highly influenced by the existence of numerous dynamically-connected landscape depressions that vary in storage capacity and because of the complex freeze-thaw cycles in the region. The objective of this research was to improve sediment export simulation modeling in these cold-climate prairie watersheds by incorporating a probability distribution function of depression storage capacity and a seasonally varying soil erodibility factor into the soil and water assessment tool (SWAT) model. The probability distribution function is used to represent the variation in storage capacity of the numerous depressions, whereas the seasonally varied soil erodibility factor is used to account for changes in erodibility as the soil freezes and thaws. Results from two case study watersheds confirm an improvement in sediment export predictions when varying storage capacity is represented and the sediment loss routine includes seasonally varying soil erodibility.

Nutrient limitation of pelagic bacteria and phytoplankton in four prairie wetlands

Article

Feb 2001
Arch Hydrobiol

Marley J. Waiser

The prairie pothole region of Saskatchewan is characterized by many shallow, highly productive wetlands which support a diverse floral and faunal assemblage. Although assumed to be detritally driven, recent research has revealed that algal communities, both pelagic and attached, may be of great importance in these systems. Bacteria may also be significant. Consequently, studies of factors, for example nutrients, which control microbial growth are needed but lacking. In this study, a suite of physiological tests, including nutrient enrichment bioassays, sestonic ratios, protein to carbohydrate ratios, alkaline phosphatase activity and 32P (phosphorus) uptake and turnover times, were utilized at four prairie wetland sites to assess nutrient status of algal and bacterial communities. The results indicated that the communities were nutrient sufficient in all ponds for the majority of the ice free season. Sestonic and protein to carbohydrate ratios were within the nutrient sufficient range, alkaline phosphatase activity was low and 32P uptake and turnover times were slow for the majority of the year. Only in October did 32P uptake and turnover times indicate P-deficiency. The abundance of biologically available nutrients may be linked to pond hydrology and ability of sediments to sequester and subsequently release nutrients. It is also hypothesized that a number of mechanisms including competition for P and P bound to dissolved organic carbon, may be responsible for the P-deficiency noted in October.

Relation of Depressional Flooding to Soil Water and Upstream Accumulated Flow

Article

Apr 2015

S. D. Logsdon

Depressions may pond with water even when tiles, inlets, and ditches are present. Untiled wetlands lose more water to infiltration and evaporation since water is not lost through tiles. Water use by wetland vegetation around the wetland creates a gradient that induces lateral flow of the infiltrated water; however, field crops are often killed by flooding in the depression. The purpose of this study was to (1) use a water balance approach for calculating distribution of water to and from the depression, including modification for risers attached to inlets, and (2) relate ponding to upslope soil water deficit and crop growth around the depressions. Two depressions were monitored with "surface" wells. The north depression was larger and had two slotted risers for the two inlets, so the calculation procedure had to be modified to allow for risers. The south depression had only one inlet with no riser. For each rain event, the maximum inflow was calculated for the upslope flow accumulation. Smaller rain events saw lateral additions of only a fraction of maximum inflow because water infiltrated before reaching the depression. Calculated lateral inflow and tile outflow were too high for some events due to plugged and backed-up tiles under high flow rates. Soybean (Glycine max (L.) Merr) was killed by the extended ponding in 2010, and corn (Zea mays L.) growth was stunted in 2011, reducing evapotranspiration around the depressions. Overall, the water balance approach was useful to understand water storage and loss from depressions within a field in relation to soil water before the rain. © 2015 American Society of Agricultural and Biological Engineers.

Climate Change and Wetlands of the Prairie Pothole Region of North America: Effects, Management and Mitigation

Article

Nov 2012

Marley J. Waiser

Introduction Climate and its influence on wetlands in the PPR Wetland hydrology Linkages between climate and wetland processes Existing climate change Predicted climate change and its effects Mitigation/management of climate change Action required What is currently being done? Acknowledgements References

The Groundwater Recharge Function of Small Wetlands in the Semi-Arid Northern Prairies

Article

Apr 1998

Small wetlands in the semi-arid northern prairie region are focal points for groundwater recharge. Hence the groundwater recharge function of the wetlands is an important consideration in development of wetland conservation policies. Most of the groundwater recharge from the wetlands flows to the moist margins of the wetlands and serves to maintain high evapotranspiration by the vegetation surrounding the wetlands. Only a small portion of the recharged water flows to regional aquifers, but this portion is important for sustaining groundwater resources. Wetland drainage eliminates the local flow systems, but may have little effects on regional aquifers other than a slight lowering of the groundwater levels. Further research should focus on the effects of wetland drainage on regional groundwater levels, the role of small ephemeral ponds in groundwater recharge, and the contribution of groundwater inflow to the water balance of large permanent wetlands.

Gleysolic soils of Canada: Genesis, distribution, and classification

Article

Oct 2011
CAN J SOIL SCI

Angela Bedard-Haughn

Bedard-Haughn, A. 2011. Gleysolic soils of Canada: Genesis, distribution, and classification. Can. J. Soil Sci. 91: 763-779. This review examines the pedogenesis of Gleysolic soils, including how they affect and are affected by land use and climate change. In the Canadian System of Soil Classification, the Gleysolic Order includes all those soils with morphologic features that provide dominant physical evidence of oxidation-reduction processes or gleying. Gley features include dull coloured soil matrices and/or brightly coloured mottles, which arise due to periodic or permanently saturated conditions. Under saturated conditions, oxygen is rapidly depleted and alternative terminal electron acceptors (such as iron, Fe3+) are used by microorganisms in the decomposition of organic matter. Gleysolic soils are found throughout Canada, either in low-lying landscape positions in association with better-drained soil orders (e.g., Prairie Pothole region), or as the dominant soil type where topography and/or a slowly permeable substrate prolong the period of saturation (e.g., Clay Belt of northern Ontario and Quebec). These soils are often highly fertile agricultural land and are commonly drained for production, altering the soil-forming environment. Gleysolic soils have also been found to be potentially significant sources of greenhouse gas emissions due to high levels of denitrification and methanogenesis under their characteristic reducing conditions. Given their economic, ecologic, and environmental significance, further research is required to refine our understanding and classification of Gleysolic soils, particularly with respect to (I) how Gleysols are affected by human- or climate-change-induced changes to the drainage regime (either progressing towards reducing conditions or regressing to a non-redoximorphic state), (2) classification of carbonated and saline Gleysols, and (3) pseudogley versus groundwater Gleysols.

Sulfate salt dynamics in the glaciated plains of North America

Article

Aug 2013
J HYDROL

The semiarid glaciated plains of the North American continent, known as the prairies, are characterized by an undulating terrain rich in sulfate salts in the subsurface, with ephemeral streams and large numbers of wetlands containing seasonal or semi-permanent ponds. Salinization is a potential concern for the diverse community of vegetation, aquatic ecosystems, wildlife and agricultural production supported by the prairies, especially as a result of land use changes and climate change. In this paper, a literature review of prairie salt dynamics and distribution is presented. On the basis of observations from past field studies, a conceptual model describing prairie sulfate salt dynamics is proposed, which identifies a number of important zones of salt accumulation in the subsurface and in surface water. As is the case in any other environment, the distribution of salts is determined by the hydrological conditions, in particular subsurface flow pathways and evapotranspiration front locations. However, the semi-arid climate and glacial geology of the region result in unique and characteristic hydrological conditions and distributions of accumulated salts. The hydrology of the prairies is sensitive to land use, with the major changes over the past 100 years or so being conversion of prairie grasslands to annual dryland crops and drainage of wetlands. Moreover, in semi-arid environments the hydrological system is highly sensitive to climate variability and change. Hence, even small hydrological changes may result in mobilization of salts concentrated in the shallow subsurface, and, if sustained, may generate ground surface, wetland and surface water salinization. However, these changes are difficult to predict, involving multiple interacting processes, and it is therefore necessary to develop an improved, quantitative understanding of the coupled hydrological and geochemical processes in order to manage or adapt to future changes.

On modeling the paleohydrologic response of closed-basin lakes to fluctuations in climate: Methods, applications, and implications

Article

Apr 2014
WATER RESOUR RES

Climate reconstructions using tree rings and lake sediments have contributed significantly to the understanding of Holocene climates. Approaches focused specifically on reconstructing the temporal water-level response of lakes, however, are much less developed. This paper describes a statistical correlation approach based on time series with Palmer Drought Severity Index (PDSI) values derived from instrumental records or tree rings as a basis for reconstructing stage hydrographs for closed-basin lakes. We use a distributed lag correlation model to calculate a variable, ωt that represents the water level of a lake at any time t as a result of integrated climatic forcing from preceding years. The method was validated using both synthetic and measured lake-stage data and the study found that a lake's “memory” of climate fades as time passes, following an exponential-decay function at rates determined by the correlation time lag. Calculated trends in ωt for Moon Lake, Rice Lake, and Lake Mina from AD 1401 to 1860 compared well with the established chronologies (salinity, moisture, and Mg/Ca ratios) reconstructed from sediments. This method provides an independent approach for developing high-resolution information on lake behaviors in pre-instrumental times and has been able to identify problems of climate signal deterioration in sediment-based climate reconstructions in lakes with a long time lag.

Landscape characteristics influence the spatial pattern of soil water storage: Similarity over times and at depths

Article

May 2014
CATENA

Asim Biswas

Similarity in the spatial patterns of soil water storage (SWS) over time and at depths at multiple scales and locations reflects the similarity in the underlying hydrological processes. The objective of this study was to examine the similarity in the spatial patterns of SWS and its characteristic landscape positions for variable soil depths and over time at a field scale. Soil water content (further converted to SWS by multiplying with depth) was measured for five years (2007–2011) along a transect of 128 points at a study site that has representative hummocky landscape of the North American Prairie Pothole region. Surface (0–20 cm) and subsurface (20–140 cm at 20 cm interval) soil water contents were measured using time domain reflectometry and a neutron probe, respectively. High rank correlation coefficient between the measurements over time and at any depth layers (surface = 0–20 cm, root zone = 0–60 cm and total active soil profile = 0–120 cm) indicated strong similarity of the spatial patterns of SWS and thus the underlying hydrological processes. The spatial patterns at large scales (> 72 m) were contributed by alternating knolls and depressions (dominant macro-topographical variations in this type of landscape) and were very similar between any measurement times and depth layers. Similarity over time was changed at medium scales (18–72 m) due to the changes in the landform elements. However, changes in the small-scale (< 18 m) spatial patterns were not associated with any landscape characteristics. Similarity was increased at different scales with increase in soil depth owing to strong buffering capacity. Information on the similarity of the spatial patterns at different scales and locations can be used to identify change in sampling domain as controlled by hydrological processes operating at different scales and locations and thus can deliver maximum information with minimum sampling efforts.

Spring runoff retention in prairie pothole wetlands

Article

Full-text available

Mar 1986
J SOIL WATER CONSERV

The volume of water in 213 small wetlands on 648 ha of the Altamont moraine in northwestern South Dakota was measured in April 1982, immediately after the vernal thaw. Water depths were measured to the nearest cm at intervals along transects through each wetland. The surface area of each wetland was obtained from low-level, black-and-white aerial photographs obtained at the same time the water depth measurements were made. The 213 wetlands comprised 50% of the water surface area that occurred in the study area and contained an estimated 19.58 ha-m (158.7 acre-feet) of water. The data are discussed in relation to what is known about prairie wetland hydrology. Values of intact prairie wetlands should be given serious consideration in water resource planning and development in the glaciated prairie region. -Authors

Three phase runoff model for small prairie rivers ii. Modelling the saturated soil phase

Article

Full-text available

Jan 1989

James M Byrne

The Conceptual Three Phase runoff model presented in Part I of this paper argues that most of the runoff volume recorded from small prairie rivers is due to the frozen soil (snowmelt) phase, and that all runoff recorded after snowmelt is due to rainfall on the saturated zone (saturated soil phase) within the basin. The extent of the saturated area SAREA is greatest just after the snowmelt season, and generally declines over summer, with small expansions in response to rainfall. An analysis of the role of SAREA has been carried out for a small river in east central Alberta. Several SAREA curves, as a function of basin storage volume, have been derived from the analyzed data, and are used to simulate the response of the Three Phase model to snowmelt and rainfall events. The quality of the fit between the recorded and simulated hydrographs indicates the Three Phase Conceptual model describes the hydrologic processes of the studied basin very closely.

Comparison of weather station snowfall with snow accumulation in High Arctic basins

Article

Full-text available

Sep 1983

Most water balance studies in the High Arctic indicate that the weather stations underestimate annual precipitation, but the magnitude of such error is unknown. Based on up to seven years of field measurements, this study provides a comparison of snowfall at weather stations with the winter snow accumulation in their nearby drainage basins.Snowfall is the major form of precipitation in the polar region for nine months every year. Without vegetation, snowdrift is controlled by the local terrain. By establishing the snow characteristics for different terrain types, total basin snow storage can be obtained by areally weighting the snow cover for various terrain units in the basin. Such a method was successfully employed to compute total winter snowfall in the drainage basins near Resolute, Eureka and Mould Bay. Results show that the basins had 130 to 300per cent more snow than the weather stations recorded. Using revised snowfall values that are reinforced by Koerner's snow core measurements from ice‐caps, it is hoped that a more realistic precipitation map can be provided for the High Arctic.

Objective Criteria for Rejecting Data for Bowen Ratio Flux Calculations

Article

Full-text available

Jan 1982

Atsumu Ohmura

In addition to the inherent problem of accumulating errors of measurement of net radiation and subsurface heat flux, the Bowen ratio energy balance method often produces totally unacceptable sensible and latent heat fluxes: wrong signs (directions) and extremely inaccurate magnitudes of the fluxes, or both. Objective criteria to eliminate undesirable data are derived in general forms. An example is graphically presented for the common case of the psychometric tower with a 0.05oC resolution limit of temperature measurements. -from Author

Objective Criteria for Rejecting Data for Bowen Ratio Flux Calculations

Article

Full-text available

Apr 1982

Atsumu Ohmura

EVAPOTRANSPIRATION AND WATER BUDGET OF PRAIRIE POTHOLES IN NORTH DAKOTA

Article

Jan 1968
U S Geol Surv Prof Pap

SHJEFLO JB

Mass-transfer method was used to study hydrologic behavior of 10 prarie potholes in central North Dakota during 5 yr period 1960-64; many of potholes went dry when precipitation was low; greatest source of water for potholes was direct rainfall on pond surface; presence of growing aquatic plants was complicating factor in making measurements; new computation procedures had to be devised to define variable mass-transfer coefficient; rating periods were divided into 6 hr units for vegetated potholes; water levels had to be recorded with such accuracy that changes of 0. 0001 ft could be detected.

Quaternary geology of Canada; in geology and economic minerals of Canada

Article

V.K. Prest

Wetlands of the prairies of Canada

Article

Jan 1988

G.D. Adams

Depression-focused transient groundwater flow patterns in Manitoba

Article

Jan 1971

A. Lissey

Modelling snowmelt infiltration and runoff in a prairie environment

Article

Jan 1986

Quaternary geology in Canada

Article

V. Prest

Hydrologic setting of wetlands in the Cottonwood Lake area, Stustman country, North Dakota

Article

Jan 1980

Wetland and Lake Evaporation in the Low Arctic

Article

May 1986

Evaporation from wetland and lake surfaces in the continuous permafrost region of the Low Arctic was studied using an energy balance Bowen ratio approach and lysimeter measurements respectively. Daily evaporation was also estimated using the Priestley-Taylor model. Over the summer, mean evaporation from the wetland and lake were similar, but day-to-day variation was large at times. Differences of available energy and surface roughness between the lake and wetland surface produce a larger Priestly-Taylor α value for wetland evaporation. The approach presented in this paper can be used to estimate evaporation for wetland and lake surfaces in the low arctic region.

A Theoretical Analysis of Groundwater Flow in Small Drainage Basins

Article

Aug 1963
J GEOPHYS RES

József Tóth

Theoretically, three types of flow systems may occur in a small basin: local, intermediate, and regional. The local systems are separated by subvertical boundaries, and the systems of different order are separated by subhorizontal boundaries. The higher the topographic relief, the greater is the importance of the local systems. The flow lines of large unconfined flow systems do not cross major topographic features. Stagnant bodies of groundwater occur at points where flow systems meet or branch. Recharge and discharge areas alternate; thus only part of the basin will contribute to the baseflow of its main stream. Motion of groundwater is sluggish or nil under extended flat areas, with little chance of the water being freshened. Water level fluctuations decrease with depth, and only a small percentage of the total volume of the groundwater in the basin participates in the hydrologic cycle.

Hydrology and Chemistry of Selected Prairie Wetlands in Cottonwood Lake Area, Stutsman County, North Dakota

Book

Jan 1987

he relation of hydrologic setting and temporal variability in hydrology to nutrient content and geochemical characteristics of a group of prairie wetlands and adjacent ground water was studied during the period 1979-82. Although data were collected from many wetlands and wells at the study site, emphasis in this report primarily is on four wetlands-two seasonal and two semipermanent-and four wells contiguous to them along a hydrologic section. The seasonal wetlands, T8 and T3, contained water only for a few weeks to months after filling in spring and early summer; both were completely dry by August. The semipermanent wetlands, PI and P8, contained water throughout each year and were ice covered in winter. One wetland, T8, recharges ground water. Wetlands PI and P8 are in areas of ground-water discharge. None of the wetlands received water by channelized surface-water inlets. Only wetland P8 had a channelized surface-water outlet. Ground-water-Ievel data showed that high points of the water table did not always occur beneath land-surface highs. Reversals of ground-water flow occurred occasionally between two of the wetlands, T3 and PI. ,,,,Significant differences existed in the chemical composition of the wetlands based on their hydrologic setting. In general, the dominant cation and anion in the wetlands were potassium and bicarbonate in wetland T8, calcium and sulfate in wetland T3, magnesium and sulfate in wetland PI, and magnesium and bicarbonate in wetland P8. Significant seasonal differences existed in the water chemistry of the wetlands in ground-water discharge areas. Water in three of the wetlands, T3, PI, and P8, was most dilute while they filled in spring after ice melt. Concentration increased during the open-water period, and two of the wetlands, PI and P8, became most concentrated under ice cover. Concentrations of total phosphorus and total nitrogen were greatest in wetlands in areas of ground-water recharge and least in wetlands in areas of ground-water discharge. Differences in the chemistry of water from wells in the adjacent ground water resulted primarily from the positions of the wells in the ground-water flow system. The chemical type of water from well 12, which was located in a ground-water recharge area, was calcium sodium bicarbonate. Water from well 4, located downgradient from wetland T8, and from well 16, located downgradient from wetland PI, typically was a calcium sulfate type. Water from well 13, located between wetlands T3 and PI in an area of changing ground-water flow directions, was a magnesium sulfate type. Data from this study show that an understanding of hydrologic conditions is important in the interpretation of the water chemistry of wetlands in the study area.

The Interaction of Lakes With Variably Saturated Porous Media

Article

Oct 1983

Thomas C. Winter

Numerical simulation of variably saturated porous media indicates that groundwater recharge is variable in time and space, depending on the thickness of the unsaturated zone through which infiltrating water must move. The resulting complex, transient groundwater flow systems have significant impact on contiguous surface water. In very permeable media, small, local, closed groundwater flow systems can develop and dissipate within a few weeks to several months after major recharge. These have a direct effect on contiguous surface water by alternately causing seepage to and seepage from the surface water. The transient nature of these flow systems indicates that reversals of the direction of groundwater flow may be common. In less permeable media the same complex flow systems may occur, but the time for development and dissipation is much greater. For example, it is conceivable that small, local flow systems may exist for many months or years as a result of major recharge. Therefore directions of flow in such systems are more stable, and the effect on contiguous surface water also is more stable. The findings of this study indicate that wells and groundwater quality sampling sites need to be carefully located to define accurately water table configuration, groundwater recharge, direction of seepage through the beds of surface water bodies, and complex geochemical processes related to changing directions of groundwater flow.

Snow Surface Energy Exchange

Article

Jun 1981

The release of snow in the form of melt water is important to agriculture, hydroelectric power generation, urban water supply, and flood control over a large part of the Northern Hemisphere. One of the factors governing the rate of production of melt water is the energy exchange at the snow surface. The two most important exchange processes are radiation transfer (short- and long-wave) and the turbulent exchange process (sensible and latent heat transfer). The present review considers these two processes exclusively. The radiation exchange is frequently the dominant transfer process during snowmelt on the prairies, in the northern forests, and in mountainous terrain. Methods for modeling radiation on an areal basis during clear days in open areas are well advanced and agreement between calculations and measurements is good although measured data are scarce in the literature. The presence of a forest cover or cloudy skies complicates the modeling process, but relatively simple procedures have been developed in the past few years which are sufficiently accurate for many water management purposes. Sensible and latent heat transfer has been measured at a variety of sites throughout the world. When results are compared it is obvious that such factors as prevailing air mass conditions, altitude, time of year, and terrain features influence the relative importance of turbulent exchange and radiation transfer. As yet there are insufficient data to distinguish trends among these factors with any clarity although the air mass is clearly important and should be considered in future studies of the energy exchange process.

Long-term soil moisture status in southern Alberta

Article

May 1990
CAN J SOIL SCI

Nineteen years of soil moisture content data at Lethbridge and two locations near Turin were examined to evaluate the efficiency of fallow for conserving moisture, and to calculate the long-term mean amount of water recharge during growing and nongrowing seasons under a fallow-cereal, 2-yr rotation and a continuous cropping system. The significantly higher soil water content at the 90- to 120-cm depth for the fallow field than for other fields during various periods of time indicates that the soil water recharge from precipitation might be deeper in the fallow field than in continuous cropping and fresh stubble of fallow-cereal rotation fields. The deeper soil water recharge could increase the available soil moisture for crop production and it could also contribute to ground water recharge. -from Authors

The Effect of Groundwater on Soil Formation in a Morainal Landscape in Saskatchewan

Article

May 1985
CAN J SOIL SCI

The results of this study indicate the importance of groundwater flow and water table depth on the genesis, characteristics and distribution of soils within a hummocky morainal landscape. Soil types on uplands are more dependent on slope position and infiltration than on depth to water table or groundwater flow. Non-saline soils of different profile types occur on mid- and upper slope positions. These areas have a deep water table with mainly recharge or lateral flow occurring in the saturated zone. The infiltration of surface runoff water in upland depressions is the dominant factor influencing the distribution of soluble salts in this hummocky landscape.-from Authors

An examination of the concept of potential

Article

Nov 1989
J HYDROL

R. J. Granger

A survey of the literature reveals that the concept of potential evaporation has been the source of some ambiguity; there exists a multiplicity of “definitions”, which can in fact represent several distinct parameters.A systematic approach is used to derive a series of distinct “potential evaporation parameters”. The evaporating surface is considered as a system to and from which energy and vapor can be transferred; the potential evaporation parameters describe the evaporation rates which occur when prescribed changes, including saturating the surface, are imposed on this system. Of the defined potential evaporation parameters, the most useful are: (1) the “equilibrium” evaporation rate, governed solely by the available energy, which represents a lower limit to evaporation from moist surfaces; (2) the “wet-surface” evaporation, governed by the available energy and atmospheric considerations, and which is represented by the Penman equation; and (3) the “potential” evaporation, which is defined by the atmospheric conditions and the saturation vapor pressure at the actual surface temperature, and which represents an upper limit to evaporation from a moist surface.

Mass-transfer studies to determine the groundwater regime of permanent lakes in hummocky moraine of Western Canada

Article

Dec 1967
J HYDROL

Peter Meyboom

The results of this study indicate that permanent lakes in hummocky moraine are all situated in discharge areas of local or intermediate groundwater flow systems. One can distinguish four typical conditions of unsteady groundwater flow near these lakes: (1) A spring condition of groundwater inflow from the underlying flow system(s), (2) A summer condition of flow towards the phreatophyte fringe around the lakes. This flow is made up of induced seepage from the lake and diverted groundwater flow, (3) Another summer condition is one of shallow leakage between adjacent lakes, produced by a deteriorating local flow system, (4) A typical condition for fall and winter is either one of continuous groundwater inflow (as during spring) or one of shallow leakage superimposed on groundwater discharge from the underlying flow system(s). Each one of these conditions can be detected from a careful analysis of mass-transfer plots.With regard to the mass-transfer studies as such, three conclusions stand out: (1) more than one series of mass-transfer measurements are required to determine the precise groundwater regime near permanent lakes, (2) even if Langbein's assumption of steady seepage is not satisfied, 48-hour mass-transfer plots, together with measurements of hydraulic head, give clear insight as to how the seepage rates are changing, be it hourly, daily or seasonally, (3) the mass-transfer coefficient N is not a constant for any given lake, but varies exponentially with evaporative power. Moreover, N was found to decrease throughout the summer by about 50 percent.

Transient Ground Water Flow Surrounding a Recharge Slough in a Till Plain

Article

Feb 1986
CAN J SOIL SCI

Knowledge of the groundwater flow system around a slough aids in the resolution of conflicting opinions on slough drainage. This study reports on the flow system around a typical temporary slough in a low relief till plain landscape. The site is located in a regional groundwater recharge area, with till of low hydraulic conductivity overlying a shale aquifer. The distribution of soil profile types in the landscape reflects a wide range of soil water regimes. Instrumentation at the site revealed an annual cycle of water levels and transient flow that was related to spring ponding of water in the slough. Numerical simulation of the flow system, under conditions of ponding, surface saturation, and evapotranspiration, helped to clarify and extend the field observations. Each depression in the landscape has a local flow system that is superimposed on the regional system. Hydraulic conductivity, water supply to the slough, and the amount and timing of infiltration and exfiltration all affect the local flow system. Temporary sloughs, such as the one studied, do not benefit agriculture, but drainage of these sloughs raises other concerns. Key words: Groundwater, transient flow, recharge, slough, pothole, simulation

Problems in Developing a Physically Based Snowmelt Model

Article

Feb 2011
CAN J CIVIL ENG

Over the past few years several snowmelt simulation models have been developed as an aid to streamflow forecasting in mountainous regions. This paper describes the major difficulties encountered when simulation of Prairie snowmelt conditions is attempted, not only for the purpose of forecasting streamflow, but also soil moisture, evaporation, and snow distribution patterns. Simulation is discussed in terms of the energy equation for the snowpack and it is shown that the improvement of the model depends on the following factors: (i) the adjustment of the radiation flux at the snow surface for slope and aspect, (ii) the development of procedures which will allow estimates of the areal distribution of sensible heat, (iii) successful modelling of the diurnal freeze–thaw cycle common to Prairie snowpacks, (iv) an investigation of the energy exchange processes during the period when the snow cover is discontinuous or patchy, (v) knowledge of the coupling of heat and mass transfer processes in frozen soils, and (vi) the extrapolation of point estimates of significant parameters to an areal basis.

An Energy-Budget Snowmelt Model for the Canadian Prairies

Article

Feb 2011

Meltwater released by shallow snow covers of the Canadian Prairies is an important water resource to the region. Therefore, many water-management agencies are interested in methods of forecasting streamflow and seasonal water yield from snowmelt. Reliable, accurate forecasts, however, require information of the time of melt and snowmelt rates and volumes. At the present time these quantities are usually estimated by simple temperature-index methods, which have not proven successful in open grassland environments.The paper describes the development and testing of a snowmelt model that uses the energy equation as its physical framework. Empirical procedures for evaluating radiative, convective, advective, and internal-energy terms from standard climatological measurements are presented. Algorithms for accounting for changes in the energy terms in a daily energy-balance model are described.The application of the energy-budget snowmelt model (EBSM) for predicting ablation and simulating streamflow from small and large watersheds is evaluated. It is demonstrated that the EBSM is workable in an operational forecast system and when incorporated within such a system leads to general improvement in synthesizing streamflow from snowmelt.

Snowmelt Infiltration to Frozen Prairie Soils

Article

Feb 2011

The paper summarizes the results of 5 years of study of the interaction between snowmelt infiltration (INF), snow-cover water equivalent (SWE), and soil moisture content at the time of melt (θp) for soils in the Brown and Dark Brown zones of the Canadian Prairies. It is shown that in uncracked soils the depth infiltrating water percolates into the soil during the melt sequence is, on the average, approximately 30 cm and that θp of the frozen layer at the soil surface (0–30 cm) is the dominant factor governing the amount of snowmelt infiltration, independent of soil texture and vegetative cover. Empirical expressions, in the form of power equations and graphs, are presented describing the relationship between the variables. Because of their simplicity they have direct practical application to a number of water management problems of the region. A conceptual model for describing the snowmelt infiltration phenomenon in operational water management schemes is presented. It divides the infiltration potential of Prairie soils into three broad categories: unlimited, limited, and restricted, based on the water entry, transmission, and storage properties of the frozen ground.

On the Assessment of Surface Heat Flux and Evaporation Using Large Scale Parameters

Article

Feb 1972

Evaporation into the Atmosphere

Book

Jan 1982

W. A. Brutsaert

Equilibrium, Potential and Actual Evaporation from Cropped Surfaces in Southern Ontario

Article

Jun 1973

Micrometeorological data collected over cropped surfaces at Simcoe in southern Ontario are used to evaluate various evaporation rates. Data collected in 1971 from two plots of perennial ryegrass, one of which was irrigated, show that daily potential evaporation (PE), taken as the evaporation rate from the irrigated plot, is related to an `equilibrium' rate (PES) by PE = PES, where = 1.27. This value of is very similar to that reported by Priestley and Taylor. Previous data for other crops support this value. Data from elsewhere are included to show why the value should be a best estimate of for air temperatures between 15 and 30C. It follows that at temperatures over 25C the surface net radiation should be a good estimate of PE. Actual and equilibrium evaporation values for the dry grass plot in 1971 compared closely on moderately dry days, confirming previous results. An approach to calculating daily evaporation is presented which utilizes PES and surface soil moisture.

The energy balance in the coastal environment of James Bay and Hudson Bay during the growing season

Article

Mar 1987
INT J CLIMATOL

Energy balance measurements were made simultaneously at a terrestrial site in southern James Bay (SJB) and one in central Hudson Bay (CHB) during the growing season of 1985. Both sites were located 1 km inland from east‐west trending coastlines and both were fully vegetated with sedge grasses growing in standing water. The SJB site is in a non‐permafrost environment, whereas the CHB site is underlain by continuous permafrost. The measurements indicate that the magnitudes of all components of the energy balance, except net radiation, are strongly dependent on wind direction. Onshore winds are dominant. With onshore winds, the ground heat flux, evaporative heat flux and air temperature are smaller than for offshore winds and the sensible heat flux is larger. These relationships are apparent when the wind is directionally persistent for a full day and when there is a major wind shift between onshore and offshore during the day. With colder air temperatures the Bowen ratio becomes much larger than would be expected under conditions of potential evapotranspiration. This appears to be caused by a rapid increase in the canopy resistance of sedge grasses which occurs when air temperatures drop below 16°C. Components of the energy balance are linearly correlated with air temperature. This could be useful in predicting the impact of human activities which result in long term temperature change in the Hudson Bay lowlands, which is a large area with a very sparse climate database.

Water flow in a hummocky landscape in Central Saskatchewan, Canada, II. Saturated flow and groundwater recharge

Article

Sep 1989
J HYDROL

Relatively few estimates of the rate of groundwater recharge have been obtained in the Interior Plains region of North America. The purpose of this study was to characterize the saturated flow system surrounding two sloughs in a hummocky upland area in central Saskatchewan and to estimate the groundwater recharge rate.The saturated flow system was dominated by two factors. First, deposits at the soil surface had a high hydraulic conductivity which resulted in rapid horizontal flow at shallow depth at the edge of the sloughs. Second, a low hydraulic conductivity layer at approximately 12 m depth impeded the rate of vertical flow. The annual fluctuation of the water table in the sloughs was in the order of 2 m, but this fluctuation was buffered by a 10 m deep saturated zone over the impeding layer, and the system approximated steady state flow.The groundwater recharge rates for the sloughs ranged from 250 to 300 mm yr−1. Accumulation of soluble salts, as indicated by electrical conductivity, and high soluble Mg2+/Ca2+ ratios above 5 m depth in the midslope and knoll positions indicated that minimal groundwater recharge had occurred in the past. A regional recharge rate of approximately 35 mm yr−1 or 10% of the annual precipitation was calculated based on the recharge rate and areal extent of sloughs.

Hydrogeology of two Saskatchewan tills, I. Fractures, bulk permeability, and spatial variability of downward flow

Article

Jun 1988
J HYDROL

Groundwater flow patterns were compared and contrasted in two deposits of clayey till of different thicknesses, both of which overlie regional aquifers in a flat upland recharge area. Analysis of 67 field and laboratory hydraulic conductivity determinations indicated that conductive fractures in the unoxidized zone of the thinner till (Dalmeny site) give rise to an isotropic bulk permeability of approximately 5 × 10−9 ms−1, which is two orders of magnitude greater than the bulk permeability of unoxidized till in the thicker deposit (Warman site). Vertical pore water velocities, estimated using hydraulic and isotopic evidence, vary greatly at Dalmeny and appear to be of the order of 8 m in 10,000 yr at Warman. The association of vertical groundwater flux, depth to water table, and depth of oxidized zone at a given location is referred to as the flow regime there. Spatially detailed water-level monitoring and test drilling indicated substantial variation of the flow regime at Dalmeny on a horizontal scale of tens of meters. No such variation exists at Warman. The differentiation of the flow regime at Dalmeny is due to higher till permeability, which permits a spatially-variable response to microtopographically-focussed infiltration of surface water. Recognition of the causes and symptoms of flow regime variability beneath flat till landscapes has implications for environmental assessment procedures, agricultural practices, wetland management, and waste disposal.

Unsteady Groundwater Flow Near a Willow Ring in Hummocky Moraine

Article

Dec 1966
J HYDROL

P. Meyboom

This article describes three types of groundwater flow that are associated with a ring of willows and the enclosed temporary slough in hummocky moraine of south-central Saskatchewan. During the course of one water-year the following sequence of flow-conditions can be recognized: (1) a winter condition of “normal” downward flow, (2) a spring condition characterized by a groundwater mound underneath the slough and an associated flow pattern of lateral and vertical dissipation, and finally (3) a condition of inverted water-table relief owing to a cone of depression around the phreatophytic willows and the phreatophytes in the dry slough bed. The latter condition which exists during summer and fall, is characterized by radial flow into the willow ring brought about by reversed-shallow and diverted-deep groundwater flow.A water balance of the willow ring from May 31, 1964 to June 1, 1965, showed that the overall effect of conditions 1 and 2 was a net contribution to the regional groundwater resources of 2 914 cubic feet which represents 0.42 inches on the 2-acre watershed around the slough.

Evaporation From Natural Non-Saturated Surfaces

Article

Nov 1989
J HYDROL

Following a development similar to that used by Penman (1948) a general combination equation is derived to describe evaporation from nonsaturated surfaces. To account for departure from saturated conditions, the equation makes use of the concept of relative evaporation, the ratio of the actual to the potential evaporation, defined here as the evaporation rate which would occur under the existing atmospheric conditions if the surface were saturated at the actual surface temperature. A relationship is established between the relative evaporation and a dimensionless parameter called the relative drying power, the ratio of the drying power to the sum of the drying power and the net available energy (net radiation plus soil heat flux). The relationship is nondimensional and appears to be single-valued. The combination of this relationship with the general evaporation equation derived constitutes a simple model for obtaining estimates of evaporation from nonsaturated surfaces; no prior estimate of the potential evaporation is required, and the surface conditions of temperature and humidity need not be known.

Boundary Layer Climates

Chapter

Jan 1993

T. R. Oke

We also thank the reviewers for their insightful comments Wetlands of the prairies of Canada

Jan 1988
155-198

M.-K Woo
R D Rowsell
M.-K Woo
R D Rowsell
Doug Clark
Tony Craig
Rick Diamond
Dan Lawford
Wally Matthews
Geoff Nicholaichuk
Tony Strong
G D Wankiewicz Adams

M.-K. WOO AND R.D. ROWSELL M.-K. WOO AND R.D. ROWSELL Clark, Doug Craig, Tony Diamond, Rick Lawford, Dan Matthews, Wally Nicholaichuk, Geoff Strong and Tony Wankiewicz. We also thank the reviewers for their insightful comments. REFERENCES Adams, G.D., 1988. Wetlands of the prairies of Canada. In: National Wetlands Working Group (Editors), Wetlands of Canada. Ecological Land Classification Series, No. 24. Environment Canada and Polyscience Publications, Montreal, Que., pp. 155-198.

Frequency analysis of meteorological drought in the Saskatchewan portion of the South Saskatchewan River basin

Jan 1988
335

Bauer

Bauer, D.J. and Welsh, L.E., 1988. Frequency analysis of meteorological drought in the Saskatchewan portion of the South Saskatchewan River basin. In: D.J. Bauer (Editor), Proc of the Prairie Drought Workshop, NHRI Symposium No. 2, 11-13 October 1988, Saskatoon, Sask., Environment Canada, Saskatoon, Sask., pp. 335-348.

Energy and mass exchange of a native grassland in Saskatchewan

Jan 1975
1827

Ripley

Ripley, E.A. and Saugier, B., 1975. Energy and mass exchange of a native grassland in Saskatchewan. In: D.A. deVries and N.A. Afgan (Editors), Heat and Mass Transfer in the Biosphere. Wiley, Toronto, Ont., pp. 1827-1832.

Evaporation into the Atmosphere. Reidel, Dordrecht, 299 pp Three phase runoff model for small prairie rivers I: frost soil assessment

Jan 1982
18-29

W H Brutsaert

Brutsaert, W.H., 1982. Evaporation into the Atmosphere. Reidel, Dordrecht, 299 pp. Byrne, J.M., 1989. Three phase runoff model for small prairie rivers I: frost soil assessment. Can. Water Resour. J., 14(3): 18-29.

Specific yield — compilation of specific yields for various materials

Jan 1967
74

Johnson

Johnson, A.I., 1967. Specific yield --compilation of specific yields for various materials. U.S. Geol. Surv., Water Supply Pap., 1662-D, 74 pp.

Hydrologic studies of wetlands in the northern prairies Northern Prairie Wetlands

Jan 1989
16-54

T C Winter

Winter, T.C., 1989. Hydrologic studies of wetlands in the northern prairies. In: A. Van der Valk (Editor), Northern Prairie Wetlands. Iowa State University Press, Ames, IA, pp. 16 54.

Hydrologic investigations of prairie potholes in North Dakota, 1959–1968

Jan 1972
102

Eisenlohr

Eisenlohr, Jr., W.S., et al. 1972. Hydrologic investigations of prairie potholes in North Dakota, 1959-1968. U.S. Geol. Surv., Prof. Pap. 585-A, 102 pp.

Ground-water hydrology of prairie potholes in North Dakota

Jan 1972
28

Sloan

Sloan, C.E., 1972. Ground-water hydrology of prairie potholes in North Dakota. U.S, Geol. Surv., Prof. Pap., 585-C, 28 pp.

Patterns of groundwater flow in the prairie profile

Jan 1963
5

Meyboom

Meyboom, P., 1963. Patterns of groundwater flow in the prairie profile. In: Proc. Hydrology Syrup. No. 3, Groundwater, Calgary, 8-9 November 1962. Queen's Printer, Ottawa, Ont., pp. 5-26.

Hydrologic studies of wetlands in the northern prairies

Jan 1989
16

Winter

Three phase runoff model for small prairie rivers I: frost soil assessment

Jan 1989
18

Byrne

Hydrogeology in two Saskatchewan tills

Jan 1988
97

Keller

Hydrology of a Prairie Slough

Abstract

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