Development of a Field-Scale Research Facility to Assess the Effects of Sea L...RachelMordovancey
This project encapsulated engineering and ecological design to develop a site for a sea level rise research facility in the Santee Experimental Forest in Huger, SC.
Catchment classification: multivariate statistical analyses for physiographic...IJERA Editor
The objective of this study was to determine physiographic similarity, as indicator of hydrologic similarity
between catchments located in the Upper Niger Basin, and to derive the dominant factors controlling each group
singularity. We utilized a dataset of 9 catchments described by 16 physical and climatic properties distributed
across a wide region with strong environmental gradients. Catchments attributes were first standardized before
they underwent an integrated exploratory data analysis composed by Principal Component Analysis (PCA)
followed by Hierarchical Clustering. Results showed a clear distribution into 2 major clusters: a group of
easterly flat catchments and another of westerly hilly catchments. This nomenclature came from the
interpretation of the main factors, topography and longitude, that seem to control the most important variability
between both clusters. In addition, the hilly catchments were designated to be dominated by forest and
ACRISOL soil type, two additional drivers of similarity. The outcome of this study can help understanding
catchment functioning and provide a support for regionalization of hydrological information.
Development of a Field-Scale Research Facility to Assess the Effects of Sea L...RachelMordovancey
This project encapsulated engineering and ecological design to develop a site for a sea level rise research facility in the Santee Experimental Forest in Huger, SC.
Catchment classification: multivariate statistical analyses for physiographic...IJERA Editor
The objective of this study was to determine physiographic similarity, as indicator of hydrologic similarity
between catchments located in the Upper Niger Basin, and to derive the dominant factors controlling each group
singularity. We utilized a dataset of 9 catchments described by 16 physical and climatic properties distributed
across a wide region with strong environmental gradients. Catchments attributes were first standardized before
they underwent an integrated exploratory data analysis composed by Principal Component Analysis (PCA)
followed by Hierarchical Clustering. Results showed a clear distribution into 2 major clusters: a group of
easterly flat catchments and another of westerly hilly catchments. This nomenclature came from the
interpretation of the main factors, topography and longitude, that seem to control the most important variability
between both clusters. In addition, the hilly catchments were designated to be dominated by forest and
ACRISOL soil type, two additional drivers of similarity. The outcome of this study can help understanding
catchment functioning and provide a support for regionalization of hydrological information.
Modeling the Effects of Sea Level Rise on Coastal Wetlands
Marc Carullo, GIS/Environmental Analyst, Massachusetts Office of Coastal Zone Management (CZM)
Hydrodynamics and Morphological Changes Numerical Model of the Jeneberang Est...AM Publications
Jeneberang Estuary, located south of Makassar, Indonesia, is one of the largest and most important river in Sulawesi. In this paper, a numerical model has recently been developed hydrodynamic and morphological evolution of the downstream rubber dam of the Jeneberang Estuary. The hydrodynamic model is derived from the hydro static assumption and Boussinesq approximation. A high-resolution computational grid was generated covering the Jeneberang estuary. The model was run with time driven by tidal forcing at the ocean boundary and river hydro graph at the upstream. The observed tidal data and hydrography were accessible for the set-up of the model. Hydrodynamic simulations have been performed and computed water levels were compared to observations of existing water level along the estuary from DISHIDRO data. For the period of a neap-spring-neap cycle, the model settings determined in the calibration process are verified satisfactions with respect to water level measurements. Good agreement was shown between model results and observed temporal and spatial variations in water elevation and currents, in the Jeneberang Estuary. The suspended sediments were generally transported from the Jeneberang River towards the Makassar Strait when overflow discharge through the Jeneberang Rubber Dam. Morphology change at the Jeneberang Estuary delta is affected by many factors, including tide, waves, river flows and sediment
Delineation of Hydrocarbon Bearing Reservoirs from Surface Seismic and Well L...IOSR Journals
Hydrocarbon reservoir has been delineated and their boundaries mapped using direct indicators from 3-D seismic and well log data from an oil field in Nembe creek, Niger Delta region. Well log signatures were employed to identify hydrocarbon bearing sands. Well to seismic correlation revealed that these reservoirs tied with direct hydrocarbon indicators on the seismic section. The results of the interpreted well logs revealed that the hydrocarbon interval in the area occurs between 6450ft to 6533ft for well A, 6449ft to 6537ft for well B and 6629ft to 6704ft for well C; which were delineated using the resistivity, water saturation and gamma ray logs. Cross plot analysis was carried out to validate the sensitivity of the rock attributes to reservoir saturation condition. Analysis of the extracted seismic attribute slices revealed HD5000 as hydrocarbon bearing reservoir.
Modeling the Effects of Sea Level Rise on Coastal Wetlands
Marc Carullo, GIS/Environmental Analyst, Massachusetts Office of Coastal Zone Management (CZM)
Hydrodynamics and Morphological Changes Numerical Model of the Jeneberang Est...AM Publications
Jeneberang Estuary, located south of Makassar, Indonesia, is one of the largest and most important river in Sulawesi. In this paper, a numerical model has recently been developed hydrodynamic and morphological evolution of the downstream rubber dam of the Jeneberang Estuary. The hydrodynamic model is derived from the hydro static assumption and Boussinesq approximation. A high-resolution computational grid was generated covering the Jeneberang estuary. The model was run with time driven by tidal forcing at the ocean boundary and river hydro graph at the upstream. The observed tidal data and hydrography were accessible for the set-up of the model. Hydrodynamic simulations have been performed and computed water levels were compared to observations of existing water level along the estuary from DISHIDRO data. For the period of a neap-spring-neap cycle, the model settings determined in the calibration process are verified satisfactions with respect to water level measurements. Good agreement was shown between model results and observed temporal and spatial variations in water elevation and currents, in the Jeneberang Estuary. The suspended sediments were generally transported from the Jeneberang River towards the Makassar Strait when overflow discharge through the Jeneberang Rubber Dam. Morphology change at the Jeneberang Estuary delta is affected by many factors, including tide, waves, river flows and sediment
Delineation of Hydrocarbon Bearing Reservoirs from Surface Seismic and Well L...IOSR Journals
Hydrocarbon reservoir has been delineated and their boundaries mapped using direct indicators from 3-D seismic and well log data from an oil field in Nembe creek, Niger Delta region. Well log signatures were employed to identify hydrocarbon bearing sands. Well to seismic correlation revealed that these reservoirs tied with direct hydrocarbon indicators on the seismic section. The results of the interpreted well logs revealed that the hydrocarbon interval in the area occurs between 6450ft to 6533ft for well A, 6449ft to 6537ft for well B and 6629ft to 6704ft for well C; which were delineated using the resistivity, water saturation and gamma ray logs. Cross plot analysis was carried out to validate the sensitivity of the rock attributes to reservoir saturation condition. Analysis of the extracted seismic attribute slices revealed HD5000 as hydrocarbon bearing reservoir.
Climate change is projected to impact drastically in southern African during the 21st century
under low mitigation futures (Niang et al., 2014). African temperatures are projected to rise
rapidly, in the subtropics at least at 1.5 times the global rate of temperature increase (James
and Washington, 2013; Engelbrecht et al., 2015). Moreover, the southern African region is
projected to become generally drier under enhanced anthropogenic forcing (Christensen et
al., 2007; Engelbrecht et al., 2009; James and Washington, 2013; Niang et al., 2014). These
changes in temperature and rainfall patterns will plausibly have a range of impacts in South
Africa, including impacts on energy demand (in terms of achieving human comfort within
buildings and factories), agriculture (e.g. reductions of yield in the maize crop under higher
temperatures and reduced soil moisture), livestock production (e.g. higher cattle mortality as
a result of oppressive temperatures) and water security (through reduced rainfall and
enhanced evapotranspiration) (Engelbrecht et al., 2015).
Introduction
How mosquitos spread ZIKA
What illnesses ZIKA is related to?
History
Symptoms
Treatment
Potential risks
Microcephaly
Which Countries should be avoid?
ZIKA in Canada
Tests
Advices
Vaccines
Surveillance
References
Un dossier sobre la presencia de Irán en Latinoamérica desde la Revolución Islámica de 1979 hasta nuestros días, incluyendo la incidencia de Hezbollah en las sociedades latinoamericanas.
In this paper, I present the concept of Solar Power Satellites -The solar cells in the satellite will convert sunlight to electricity, which will changed to radio frequency energy, then beamed to a receiver site on earth and reconverted to electricity by using transmitting and receiving antenna with the technology of wireless power transmission (i.e., transmitting power as microwaves in order to reduce the transmission and distribution losses). This concept is also known as Microwave Power Transmission.
Soil and water conservation Engineering
Drainage and Irrigation techniques and Engineering processes .
Course outline and step by step processes
Terracing and countouring
Effect of Air Relative Humidity Harvest on Soil Moisture Content under Morocc...IJERA Editor
In this work, we aim to analyse the effect of the harvest of air relative humidity on soil water content. Some experiments were conducted on hilly areas with various hypsographic and microclimatic conditions greatly affecting daily fluctuations of air relative humidity. The metrological data’s were obtained by using a Campbell Scientific equipments station recorder on data loggers every half hour. Time Domain Reflectometers (TDR) is used for calculating water content at different soil layers. The effect of many parameters such as: minimal and maximal air atmospheric humidity, potential of soil water and minimal temperature of air on harvesting air relative humidity is also discussed. The experimental results indicate that soil moisture content in the upper soil layer fluctuates with the same manner to diurnal fluctuation of relative air humidity. These fluctuations due to the harvest of relative air humidity decreased with increasing soil depth and daily amplitude of relative air humidity. The water adsorbed according to this phenomenon increased with increasing maximal relative and decreasing minimal temperature. The contribution of this soil water collected is about 40% of losses due to evaporation process. The correlation between principal climatic data and soil water adsorption by harvest relative air humidity is presented in this paper in order to incorporate it in the total water balance during water infiltration.
SETTLEMENT POTENTIALITY ANALYSIS OF CLAY SOILS, NORTH JEDDAH, SAUDI ARABIAIAEME Publication
Usually, constructors built on clay-rich soils are subjected to settlement due to compressive deformation as a result of decreasing in void space that due to rearrangement of clayey-sized grain. Settlement of the clay-rich soil leads to damage in constructions owing to decreasing in ground stability. The settlement potentiality of clay soils was increasing with increasing of both clayey-sized material content and plasticity index. The studied clay soil samples are classified as high plasticity clays (CH) and inorganic silts of high compressibility (MH). The mV-values of the studied soil samples are ranging from 0.00305cm2/gm and 0.02cm2/gm and from 0.00263cm2/gm to 0.08389 cm2/gm for clay-soil samples and silty soil samples respectively.
During the Project Puente Internship for the United States Department of Agriculture, I worked with my mentor, Dr. Eduardo Bautista. He assisted me in developing a research project for the 250 hour internship. My project was to develop and test a hanging water column for the Arid Land Agricultural Research Center (ALARC). The data gained my project can then be used to more precisely model the water content of soil following irrigation
Effect of Harvest of Air Relative Humidity on Water and Heat Transfer in Soil...IJERA Editor
In this work, the main objective is to analyze the effect of the harvest of air relative humidity on soil temperature, soil water storage and evaporation. An experiment work was conducted in order to evaluate the quantity of soil water adsorbed by harvesting of relative air humidity. This experimental work was conducted on hilly areas with various hypsographic and microclimatic conditions greatly affecting daily fluctuations of air humidity and soil characteristics. The metrological data needed by SISPAT model were obtained by using a Campbell Scientific equipments Station recorder on data loggers every half hour. A numerical model based on SiSPAT (Système d’Interaction Sol Plante Atmosphère) formulation is adopted. The general equations of the proposed model are based on heat and mass transfer in the soil, atmosphere and plant system. This study shows that Soil Water Adsorption (SWA) induce an increasing in the total evaporation and in soil water storage especially on the upper layers. The effect of Soil Water Adsorption on soil temperature appears for the first layers of soil and become absent in the profound zone because the vapour condensation phenomenon is very important at night for the first layers.
Effect of Harvest of Air Relative Humidity on Water and Heat Transfer in Soil...IJERA Editor
In this work, the main objective is to analyze the effect of the harvest of air relative humidity on soil temperature, soil water storage and evaporation. An experiment work was conducted in order to evaluate the quantity of soil water adsorbed by harvesting of relative air humidity. This experimental work was conducted on hilly areas with various hypsographic and microclimatic conditions greatly affecting daily fluctuations of air humidity and soil characteristics. The metrological data needed by SISPAT model were obtained by using a Campbell Scientific equipments Station recorder on data loggers every half hour. A numerical model based on SiSPAT (Système d’Interaction Sol Plante Atmosphère) formulation is adopted. The general equations of the proposed model are based on heat and mass transfer in the soil, atmosphere and plant system. This study shows that Soil Water Adsorption (SWA) induce an increasing in the total evaporation and in soil water storage especially on the upper layers. The effect of Soil Water Adsorption on soil temperature appears for the first layers of soil and become absent in the profound zone because the vapour condensation phenomenon is very important at night for the first layers.
Aptitude of Ground waters for Irrigation in the South-East Coastal Region of ...inventionjournals
Development of agricultural areas pressures on the availability of water resources in the South-East coastal region of Côte d'Ivoire (from Abidjan to Aboisso) require farmers to use groundwater for irrigation food and industrial crops. The objective of this study is to assess the aptitude of groundwater for irrigation in this region by using methods that take into account the Sodium Adsorption Report (SAR) and the Permeability Index (PI). The different results show that the SAR values range from 0.03 to 9.90 with an average of 1.83 while the PIs range from 5.11 to 210.77 with an average of 91.40. The C1S1 and C2S1 classes, corresponding to the water suitable for irrigation, represent 95% of the water sampled. In general, therefore, the sampled waters quality is suitable for irrigation except the boreholes waters of Memni (No. 59) and Palmafrique (No. 64).
"Understanding the Carbon Cycle: Processes, Human Impacts, and Strategies for...MMariSelvam4
The carbon cycle is a critical component of Earth's environmental system, governing the movement and transformation of carbon through various reservoirs, including the atmosphere, oceans, soil, and living organisms. This complex cycle involves several key processes such as photosynthesis, respiration, decomposition, and carbon sequestration, each contributing to the regulation of carbon levels on the planet.
Human activities, particularly fossil fuel combustion and deforestation, have significantly altered the natural carbon cycle, leading to increased atmospheric carbon dioxide concentrations and driving climate change. Understanding the intricacies of the carbon cycle is essential for assessing the impacts of these changes and developing effective mitigation strategies.
By studying the carbon cycle, scientists can identify carbon sources and sinks, measure carbon fluxes, and predict future trends. This knowledge is crucial for crafting policies aimed at reducing carbon emissions, enhancing carbon storage, and promoting sustainable practices. The carbon cycle's interplay with climate systems, ecosystems, and human activities underscores its importance in maintaining a stable and healthy planet.
In-depth exploration of the carbon cycle reveals the delicate balance required to sustain life and the urgent need to address anthropogenic influences. Through research, education, and policy, we can work towards restoring equilibrium in the carbon cycle and ensuring a sustainable future for generations to come.
Epcon is One of the World's leading Manufacturing Companies.EpconLP
Epcon is One of the World's leading Manufacturing Companies. With over 4000 installations worldwide, EPCON has been pioneering new techniques since 1977 that have become industry standards now. Founded in 1977, Epcon has grown from a one-man operation to a global leader in developing and manufacturing innovative air pollution control technology and industrial heating equipment.
Willie Nelson Net Worth: A Journey Through Music, Movies, and Business Venturesgreendigital
Willie Nelson is a name that resonates within the world of music and entertainment. Known for his unique voice, and masterful guitar skills. and an extraordinary career spanning several decades. Nelson has become a legend in the country music scene. But, his influence extends far beyond the realm of music. with ventures in acting, writing, activism, and business. This comprehensive article delves into Willie Nelson net worth. exploring the various facets of his career that have contributed to his large fortune.
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Introduction
Willie Nelson net worth is a testament to his enduring influence and success in many fields. Born on April 29, 1933, in Abbott, Texas. Nelson's journey from a humble beginning to becoming one of the most iconic figures in American music is nothing short of inspirational. His net worth, which estimated to be around $25 million as of 2024. reflects a career that is as diverse as it is prolific.
Early Life and Musical Beginnings
Humble Origins
Willie Hugh Nelson was born during the Great Depression. a time of significant economic hardship in the United States. Raised by his grandparents. Nelson found solace and inspiration in music from an early age. His grandmother taught him to play the guitar. setting the stage for what would become an illustrious career.
First Steps in Music
Nelson's initial foray into the music industry was fraught with challenges. He moved to Nashville, Tennessee, to pursue his dreams, but success did not come . Working as a songwriter, Nelson penned hits for other artists. which helped him gain a foothold in the competitive music scene. His songwriting skills contributed to his early earnings. laying the foundation for his net worth.
Rise to Stardom
Breakthrough Albums
The 1970s marked a turning point in Willie Nelson's career. His albums "Shotgun Willie" (1973), "Red Headed Stranger" (1975). and "Stardust" (1978) received critical acclaim and commercial success. These albums not only solidified his position in the country music genre. but also introduced his music to a broader audience. The success of these albums played a crucial role in boosting Willie Nelson net worth.
Iconic Songs
Willie Nelson net worth is also attributed to his extensive catalog of hit songs. Tracks like "Blue Eyes Crying in the Rain," "On the Road Again," and "Always on My Mind" have become timeless classics. These songs have not only earned Nelson large royalties but have also ensured his continued relevance in the music industry.
Acting and Film Career
Hollywood Ventures
In addition to his music career, Willie Nelson has also made a mark in Hollywood. His distinctive personality and on-screen presence have landed him roles in several films and television shows. Notable appearances include roles in "The Electric Horseman" (1979), "Honeysuckle Rose" (1980), and "Barbarosa" (1982). These acting gigs have added a significant amount to Willie Nelson net worth.
Television Appearances
Nelson's char
Climate Change All over the World .pptxsairaanwer024
Climate change refers to significant and lasting changes in the average weather patterns over periods ranging from decades to millions of years. It encompasses both global warming driven by human emissions of greenhouse gases and the resulting large-scale shifts in weather patterns. While climate change is a natural phenomenon, human activities, particularly since the Industrial Revolution, have accelerated its pace and intensity
UNDERSTANDING WHAT GREEN WASHING IS!.pdfJulietMogola
Many companies today use green washing to lure the public into thinking they are conserving the environment but in real sense they are doing more harm. There have been such several cases from very big companies here in Kenya and also globally. This ranges from various sectors from manufacturing and goes to consumer products. Educating people on greenwashing will enable people to make better choices based on their analysis and not on what they see on marketing sites.
Artificial Reefs by Kuddle Life Foundation - May 2024punit537210
Situated in Pondicherry, India, Kuddle Life Foundation is a charitable, non-profit and non-governmental organization (NGO) dedicated to improving the living standards of coastal communities and simultaneously placing a strong emphasis on the protection of marine ecosystems.
One of the key areas we work in is Artificial Reefs. This presentation captures our journey so far and our learnings. We hope you get as excited about marine conservation and artificial reefs as we are.
Please visit our website: https://kuddlelife.org
Our Instagram channel:
@kuddlelifefoundation
Our Linkedin Page:
https://www.linkedin.com/company/kuddlelifefoundation/
and write to us if you have any questions:
info@kuddlelife.org
WRI’s brand new “Food Service Playbook for Promoting Sustainable Food Choices” gives food service operators the very latest strategies for creating dining environments that empower consumers to choose sustainable, plant-rich dishes. This research builds off our first guide for food service, now with industry experience and insights from nearly 350 academic trials.
Characterization and the Kinetics of drying at the drying oven and with micro...Open Access Research Paper
The objective of this work is to contribute to valorization de Nephelium lappaceum by the characterization of kinetics of drying of seeds of Nephelium lappaceum. The seeds were dehydrated until a constant mass respectively in a drying oven and a microwawe oven. The temperatures and the powers of drying are respectively: 50, 60 and 70°C and 140, 280 and 420 W. The results show that the curves of drying of seeds of Nephelium lappaceum do not present a phase of constant kinetics. The coefficients of diffusion vary between 2.09.10-8 to 2.98. 10-8m-2/s in the interval of 50°C at 70°C and between 4.83×10-07 at 9.04×10-07 m-8/s for the powers going of 140 W with 420 W the relation between Arrhenius and a value of energy of activation of 16.49 kJ. mol-1 expressed the effect of the temperature on effective diffusivity.
Summary of the Climate and Energy Policy of Australia
Price mc laren rudolph fen creation 2010
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2. Landscape restoration after oil sands mining: conceptual design and
hydrological modelling for fen reconstruction
Jonathan S. Pricea
*, Robert G. McLarenb
and David L. Rudolphb
a
Department of Geography and Environmental Management, University of Waterloo,
Waterloo, ON, Canada; b
Department of Earth and Environmental Science,
University of Waterloo, Waterloo, ON, Canada
(Received 9 March 2009; final version received 8 April 2009)
Extraction of oil sands in the relatively dry Western Boreal Plains near Fort
McMurray, Alberta, destroys the natural surface cover including fen peatlands
that cover upto 65% of the landscape. Industry and environmental monitoring
agencies have questioned the ability to reclaim fen peatlands in the post-mine
landscape. This study proposes a conceptual model to replace fen systems with
fen peat materials supported by groundwater inflow from a constructed
watershed. A numerical model is used to determine the optimum system
geometry, including the ratio of upland to fen area, thickness and slope of sand
materials, and thickness of peat and of the liner that would result in flows that
sustain peat wetness to a critical threshold soil water pressure of À100 cm of
water at a peat depth of 10 cm. We also test the sensitivity of the system to
variations in the value and spatial configuration of the hydraulic conductivity (K)
of locally available materials. The optimal conditions were achieved using an
upland area at least twice that of the fen, underlain by a sloping (3%) layer of
fine-grained material with hydraulic conductivity (K) of 10À10
m/s, that maintains
lateral groundwater flow in a sand layer with K of 10À4
to 10À5
m/s. Using daily
climate inputs that included 1998, the driest summer on record, the model
suggests that adequate wetness can be sustained in the fen for the growing season,
and that the extent of water table recession was similar to undisturbed systems
during that period.
Keywords: restoration; reclamation; peatland; hydrology; hydrogeology
Introduction
The restoration of natural landscape features following open pit mining operations
has been a topic of considerable research and practical investigation for several
decades [1]. With the goal of returning a massively disturbed ground surface to a
stable terrestrial system that is sustainable from both an ecologic and hydrologic
standpoint, various field scale reconstruction projects have been undertaken. These
have been primarily focussed at sites of industrial mineral extraction and heavy
metal mining [2]. Over the last three decades, the largest open pit mining activities
worldwide have been associated with the extraction of oil sand ore [3]. One of the
*Corresponding author. Email: jsprice@uwaterloo.ca
International Journal of Mining, Reclamation and Environment
Vol. 24, No. 2, June 2010, 109–123
ISSN 1748-0930 print/ISSN 1748-0949 online
Ó 2010 Taylor & Francis
DOI: 10.1080/17480930902955724
http://www.informaworld.com
DownloadedBy:[Price,JonathanS.]At:00:5915May2010
3. major centres of oil sands mining has been in the Athabasca Oil Sands deposits north
of Fort McMurray in Alberta, Canada (Figure 1). As part of the extraction process,
overburden materials along with the terrestrial vegetation and surficial hydrologic
features that overlie the oil sand across hundreds of square kilometers of the land
surface have been stripped off and stockpiled or used as construction materials. In
fact, oil extraction activities there are expected to cover an area of *1400 km2
by
2023 [4]. The scale of the open pit mining operation is unprecedented and significant
pressure is now on the oil sands mining companies to develop plans for
landscape restoration that will be appropriate for the climatic conditions of
northern Alberta [5].
In the relatively dry climate of the Western Boreal Plain, and especially in the oil
sands development areas near Fort McMurray, peatlands, primarily fens [6],
comprise !65% of the landscape [7]. Regulatory requirements specify reclamation to
a landscape of ‘equivalent capability’ [5]. The regulation provides several options for
post-mined landscapes. One example is the development of end-pit lakes that would
result in the construction of landscape features that are not currently native to the
Western Boreal Plain. Another alternative is to re-establish peatland terrain in the
reclaimed areas. This has not previously been attempted because conventional
wisdom dictates that peatlands take thousands of years to develop [8]. However, if
peat materials acquired by surface stripping are emplaced in a hydrogeological
setting that sustains the requisite wetness condition [9], coupled with peatland
restoration techniques to establish a plant community [10], creation of a fen peatland
system may be possible. Although damaged fens have been restored [11,12], there are
no published reports of fen creation. The fundamental problem is to design a
groundwater system that can support the inflows required to sustain the hydrological
and ecological processes and functions of a fen peatland. This study considers the
possibility of engineering the landscape to provide the requisite hydrological
conditions for fen peatlands, based on a combined conceptual and mathematical
model of the associated groundwater flow processes.
Figure 1. Map of Alberta, Canada, showing the location of the Athabasca oil sands deposits.
110 J.S. Price et al.
DownloadedBy:[Price,JonathanS.]At:00:5915May2010
4. Fen peatlands are mineratrophic systems that are partly sustained by surface
and/or groundwater input, in addition to direct precipitation [13]. Some fens are
sustained through a significant input of groundwater [14]. This is likely the case for
fen systems in the relatively dry climate of the Western Boreal Plain. Indeed, some
fens in this setting have been shown to receive strong groundwater discharge [15].
Other fen features are bordered by uplands with highly transient and deep water
tables [16] that appear to provide little groundwater input yet the fen system remains
viable year round [17]. There remains, therefore, a poor understanding of the
linkages between fens and groundwater source areas in the Western Boreal Plain,
particularly in the upland setting.
The ability of certain upland-wetland configurations to support discharge to fens
is clearly feasible, based on their current existence in the natural landscape. The main
premise of the current study is to examine a suite of hydrologic conditions that could
sustain these fen-upland systems through the development and numerical testing of a
realistic conceptual model. The goal is to provide a potential approach to re-
establish the fen-upland systems within the post-mined landscape in the oil sands
region. The general approach is to test (by modelling) a hypothetical fen-upland
system, whose geometry and hydraulic properties, combined with local climate
inputs, can sustain an adequate level of wetness to support a prescribed set of fen
functions. Coarse sand tailings from processed oil sand would form the primary
aquifer, overlying a clay-based liner that directs recharged water laterally to a peat
unit derived from fen peat (i.e. currently being stripped to expose the oil-bearing
sands).
The specific objectives of this study are first to determine the optimum system
geometry, including the ratio of upland to fen area; thickness and slope of sand
materials; and thickness of peat and of the lower permeability liner that would
permit annual hydrologic sustainability of the constructed wetland. Secondly, we will
use numerical simulation to examine the sensitivity of the system to variations in the
value and spatial configuration of the hydraulic conductivity (K) of locally available
materials. The results are intended to support the establishment of a pilot-scale
facility to access the feasibility of re-establishing fen-upland systems within the oil
sand mining areas.
Study area and methods
In the Fort McMurray area, surficial overburden deposits consist mainly of glacial
till, which varies in composition from silt to clay-rich and ranges in thickness from
non-existent to tens of metres. Immediately underlying the glacial sediments are the
Cretaceous Clearwater and McMurray Formations. The Clearwater is composed of
loose shale and siltstone, and the McMurray is an oil-bearing sand formation. These
in turn overlie thick Devonian deposits of limestone and shale [18]. The lower
geologic units in the region consist of Methy Formation reefal dolomite and
Precambrian basement rocks [18].
As a result of the mining of the oil sand ore in the region, significant quantities of
the till overburden have been stripped and stockpiled. In addition, the oil extraction
process produces tailings materials ranging from fine to medium grained sands,
along with a finer secondary tailings fraction. The till and sand materials, as well as
the non-processed oil sand, are easily accessible for use in the construction of an
upland-fen system. Their hydraulic properties are described later.
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5. The geometry of the system is guided by our conceptualisation of a fen system
originating in a valley-bottom setting with lateral inputs of groundwater that are an
important component to the water budget [13]. For the purposes of modelling, the
actual dimensions are not as important as the relative proportions of the layers and
zones, thus the actual size is somewhat arbitrary. In practice, however, there is likely
a minimum size for which stable fen conditions could be created, because edge effects
would become large as the system size decreased. Consequently, a fen with *2 m of
peat, covering an area of about 1 ha, was thought to be an appropriate size. Tailings
sand (the ‘aquifer’) up to about 5 m thick covered by a 0.2 m soil layer form the
upland (contributing area for the fen, which we initially define with an area twice
that of the fen). To prevent deep seepage water loss, a low-permeability liner created
from lean oil sand or till materials with thickness must underlie these materials. Our
initial estimate of the liner thickness is 1 m. To make the simulation conservative, the
model domain includes a permeable sand tailings base area onto which the system
would be placed (Figure 2a).
Figure 2. (a) Materials distribution and (b) finite-element grid and flow boundary conditions.
112 J.S. Price et al.
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6. The conceptual model defined above was used as a base for the simulation
experiments. In considering the highly transient nature of the problem on an annual
cycle and the partially saturated conditions that exist throughout the year through
portions of the flow system, an advanced numerical modelling platform was required
to evaluate the feasibility of the proposed conceptual model and to investigate the
sensitivity of the main controlling features of the system. The details of the model are
provided below.
Model description and setup
HydroGeoSphere [19,20] was used to model the proposed fen system in a quasi 3-D
approach where a cross-sectional domain oriented through the central axis of the
constructed fen was selected for the analysis (Figure 2a). The model is a fully
integrated, variably-saturated flow and transport code that has three-dimensional
capabilities and can accommodate the generation of surface water flow. A finite
element numerical scheme was used for the domain discretisation. The peat material
that comprises the fen requires a certain minimum level of saturation to support
peatland plant communities and to reduce peat oxidation. Previous work in bog
peatlands [15] suggests the pressure in the upper peat-soil layer should not drop
below À100 cm for more than about 2 days at a time. No such thresholds have been
established in fens. However, the vascular plants more common in fen systems may
not have such stringent requirements. To remain conservative, we use this criterion
to evaluate the suitability of the proposed design. In the model the fen peat (and
constructed upland aquifer) rests directly on the liner that slopes toward the fen. The
relatively low hydraulic conductivity of this unit is intended to limit water from
percolating downward to the regional water table and instead direct it laterally into
the fen. The aquifer sand affects the storage of infiltrated water and controls the rate
at which it seeps to the fen. It is overlain by a 20 cm soil layer composed of a mixture
of peat and till [21], and provides a layer which controls infiltration and maintains a
higher level of saturation than aquifer sand, which would be more suitable for plants.
The tailings sand upon which the system rests initially has the same hydraulic
properties as the aquifer sand. Its high permeability ensures that under the long-term
average rate of infiltration it remains unsaturated, and that infiltrating water passes
readily to the regional water table, unless diverted laterally by the liner. This, along
with the low specified pressure head conditions represents the most difficult
conditions likely to be chosen for fen creation.
The soil hydraulic properties were based on water retention and hydraulic
conductivity relations for local materials including peat and soil cover materials [21],
and for sand and clay-till overburden [22] for oil sands sites. On the basis of these
relationships and determining Kunsat as a function of relative permeability, functional
hydraulic relationships were defined for each material as shown in Figure 3. As part
of the sensitivity analysis in this study, aquifer and liner material properties were
varied (Table 1). Van Genuchten parameters [23] for peat and soil were not reported
by Shurniak and Barbour [21], so a look-up table was constructed for use by the
model to define the water retention relationship in the model, based on their
published characteristic curves.
The two parameters that control the movement of water in the surface domain
are the Manning coefficient (a measure of the frictional resistance to flow) and the rill
storage height (the depth of depressions in the upper surface). No sensitivity analyses
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7. were performed for these parameters. Instead, a Manning coefficient equal to
0.0003 d/m1/3
was assigned, which is typical of a grassy surface. A rill storage height
of 0.01 m was chosen, which is small enough not to impede flow, but large enough to
enhance model stability.
Boundary conditions
In HydroGeoSphere, water can move freely between the surface and subsurface
domains (Figure 2b), depending on the size and direction of the head gradient
between them. The entire top surface of the model domain, coinciding with the
surface water domain, is a boundary of assigned flux to represent meteorologic
conditions. To establish initial flow conditions (hydraulic head and saturation)
throughout the simulation domain, a uniform P-ET flux value estimated from the
difference between annual average precipitation (P) and evapotranspiration (ET) was
run to steady state to develop this initial condition for subsequent runs.
Daily precipitation and temperature data from 1940 to 2004 were used to
determine rainfall (P) and potential evapotranspiration (PE). Daily precipitation was
considered to be rain if temperature was above 08C, and the daily water input was
equal to the rain plus snowmelt (if any). If the daily average temperature was less
than or equal to 08C, precipitation (if any) was stored (i.e. snow accumulation).
Table 1. Description of material properties for sensitivity analyses.
Saturated K (m/s) Porosity Van Genuchten a (mÀ1
) Van Genuchten n
Tailings 1 6 10À5
0.35 1.9 6
Liner I 1 6 10À9
0.55 1.9 1.8
Liner II 1 6 10À10
0.55 1.9 1.8
Liner III 1 6 10À8
0.55 1.9 1.8
Aquifer I 1 6 10À5
0.35 1.9 6
Aquifer II 1 6 10À4
0.35 1.9 6
Peat 1 6 10À5
0.7 – –
Soil 1 6 10À5
0.4 – –
Figure 3. Moisture retention curves, where P-S denotes the pressure vs. saturation
relationship and S-Krw denotes the saturation vs. relative K relationship.
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8. Snowmelt (M) was determined on the basis of air temperature (Ta) using a melt
factor (Mf) approach, where
M ¼ Mf  ðTa À MBASEÞ ð1Þ
where, Mf ¼ 0.12 mm 8CÀ1
hrÀ1
[24], adjusted to a daily value, and MBASE was 08C.
PE was determined from the Thornthwaite temperature index approach outlined
in [25], where
PE ¼ 29:8 Á D Á
eÃ
aðTaÞ
Ta þ 273:2
ð2Þ
where, PE is in mm/d, D is hours of daylight, and eÃ
aðTaÞ is the saturation vapour
pressure (kPa at the given air temperature (8C)). For the steady state condition, ET
was determined from PE based on the locally derived ratio of ET/PE ¼ 0.61 [26].
Evapotranspiration was assumed to be nil unless air temperature was above zero.
Sublimation losses from the snowpack may be important [27], but were not
accounted for. On the basis of this approach the average annual net flux (P-ET) was
179 mm. Thus, for the steady-state simulations the daily net flux of 4.904 6 10À4
m/d was initially applied until a steady-state condition was achieved, and then set to
zero to simulate drought.
For the transient simulations, the evapotranspiration formulation of Panday and
Huyakorn [28] was used to define evaporation and transpiration as a function of soil
water content based on PE as defined above. We defined two ET zones, which
represent the different characteristics of the fen and upland soil zones in the model
domain. In each case, the water loss by evapotranspiration is distributed through the
top 20 cm, corresponding to the thickness of the soil layer, with a quadratic function
that focuses loss of water by evapotranspiration to the near-surface nodes, and is
modified by a multiplier that accounts for the water storage condition of the soil.
In both evaporation and transpiration, a limiting level of saturation is specified,
below which no ET losses can occur. In this study, the wilting point was chosen for
this lower limit for both evaporation and transpiration (Table 2). At saturations
below the wilting point the evaporation and transpiration functions are multiplied by
zero. The saturation limit for the wilting point was interpolated from the pressure-
saturation relationship by assuming a pressure head value of À143 m (interpreted
from Figures 6 – 13 in Dingman, 2002 [25]).
There is also an upper limit of saturation above which the full PE is applied. In
this study, the field capacity was chosen for the upper limit of the transpiration
function. The saturation limit for the field capacity was interpolated from the
pressure-saturation relationship by assuming a pressure head value of À3.4 m
Table 2. Limiting saturation values for constraining evaporation and transpiration.
Fen Upland soil
Evaporation minimum 0.3 0.43
Evaporation maximum 0.69 0.75
Wilting point 0.3 0.43
Field capacity 0.57 0.72
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9. (interpreted from Figures 6 – 13 in Dingman, 2002 [25]). The upper saturation limit
for the evaporation function was interpolated from the pressure-saturation
relationship by assuming a pressure head value of À1 m. The multiplier rises to
1.0 at the upper saturation limit.
Other boundary conditions include a zero-gradient discharge boundary along the
upper edge of the model at x ¼ 0 (Figure 2b). This condition uses the surface water
depth and the Manning equation to calculate a discharge flux by assuming that the
slope of the water surface equals the slope of the ground surface at the boundary,
and allows water to flow freely from the surface water domain should water depths
in the peat exceed the elevation of this outlet point. Conceptually, this is similar to
outflow over a weir, whose surface elevation is identical to the peat surface elevation,
and allows surface water to drain from the system without having to specify a flow
rate or water depth. The rest of the left hand boundary is a no flow boundary (i.e.
water is only able to leave at the very top node as surface water outflow), based on
the assumption that it is located at the centre of the fen, and thus by symmetry is a
groundwater divide.The right boundary of the model is assumed to be located at the
groundwater divide in the upland region, and is likewise represented in the model as
a boundary of zero flux.
For the subsurface domain, a constant hydraulic head of À5 m is assigned to the
bottom boundary, which ensures that the water table does not drop below
the bottom of the domain considering the geometry of the specified system and the
position of the datum at the lowest point on the ground surface. This lower
boundary condition is intended to represent the presence of a regional water table
and offers a pathway for water to bypass the fen system and discharge from the
model domain if it moves below the liner.
Sensitivity analysis procedure
A base-case model geometry is defined with domain length 1000 m, peat length
200 m, peat thickness 2 m, liner thickness 1 m, liner slope 3% (outside the fen). The
upland to fen surface area ratio is defined by specifying the length of the liner – when
the liner does not extend to the right boundary, the domain to the right of the liner is
effectively removed from the area that recharges the fen. The model domain was set
up this way to simplify the procedure for altering the upland to fen ratio. The upland
to fen surface area ratio for the base-case is 2:1 (i.e. liner length outside fen 400 m,
length of fen deposit 200 m). The aquifer sand thickness varies from 2 m near the
peat to about 8 m at the upland end of the liner and about 11.4 m at the right end of
the domain (Figure 2b).
In the sensitivity analysis, key features of the proposed design are modified one at
a time, and in each case, new equilibrium conditions and responses to drought are
simulated then compared with the base case. Four sets of simulations are done with
steady-state inputs (equivalent to 179 mm/y), each set with a different combination
of liner and aquifer sand hydraulic conductivity. In each of these sets the influence of
the geometry of the systems is tested by systematically changing the liner thickness,
length and slope, and aquifer thickness. The steady-state simulations are used to find
an optimal geometry and hydraulic conductivity, and then a transient simulation is
done with these optimal properties to gauge the transient response of the fen. The
sequence and characteristics of the material and system geometry in each set of
simulations are summarised in Tables 3 and 4.
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10. Steady-state saturation and extended drought
For the initial run (Steady-state case 1), the permeability of the liner is fixed at
1 6 10À9
m/s (Liner I) and aquifer at 1 6 10À5
m/s (Aquifer I); the upland to fen
surface area ratio is 2:1; liner thickness is 1 m and the liner slope is 3% (Table 4).
Applying a steady-state surface flux of 179 mm/y (4.9 6 10À4
m/d) results in the
steady-state saturation condition shown in Figure 4. The degree of saturation in the
upland region of the sand is uniform, with a value of about 0.19. This level of
saturation results in a relative K (Krw) that, when multiplied by the saturated K,
gives an effective K that is sufficient to move the recharge water through the
Table 3. Summary of material properties used for each simulation case.
Steady state case 1 Liner I 10À9
m/s Aquifer I 10À5
m/s
Steady state case 2 Liner II 10À10
m/s Aquifer I 10À5
m/s
Steady state case 3 Liner II 10À8
m/s Aquifer I 10À5
m/s
Steady state case 4 Liner II 10À10
m/s Aquifer II 10À4
m/s
Transient case 1 Liner II 10À10
m/s Aquifer II 10À4
m/s
Transient case 2 Liner I 10À9
m/s Aquifer II 10À4
m/s
Table 4. Summary of sensitivity analysis performed for various domain characteristics for
each simulation case presented in Table 4.
Ratio Liner thickness (m) Slope (%) Aquifer thickness (m)
Base 2:1 1 3 2–8
Thicker liner 2:1 2 3 2–8
Longer liner 3:1 1 3 2–11
Shorter liner 1:1 1 3 2–5
Higher slope 2:1 1 6 2–8
Thicker aquifer 2:1 2 3 2–13
Figure 4. Initial water saturation for Liner I, Aquifer I properties with extent of liner
indicated by white line. The arrow represents the position in the fen (10 cm below the surface),
for which pressure is reported in the following simulations.
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11. unsaturated sand under a unit hydraulic gradient. The level of saturation in the peat
and liner materials are near 1.0, indicating that K of the liner is low enough to cause
sufficient water to be diverted to the peat to maintain the water table at or above
ground surface under conditions of long-term average infiltration.
The long-term drought condition is simulated by setting the surface boundary
flux to zero. The impact of this on the pressure head in the fen is shown for a point
(arrow in Figure 4) located at x ¼ 100 m and at a depth of 0.1 m below fen surface.
For the base case scenario, pressure is maintained above the critical value for a
period of 88 days regardless of the variations in the liner geometry and aquifer
thickness (Figure 5). The only design change that has a noticeable effect on the
pressure response in the fen is when the thickness of the clay liner is doubled. In this
case, the time it takes for pressure to drop below the critical value (À1 m of water)
increased from 88 to 93 days. Changes in the upland design features have little effect
on the pressure response in the fen.
If evaporation and transpiration (ET) are reduced to zero for Steady-state case 1,
soil-water pressure remains above the critical value for over 6 years (not shown in
Figure 5). Therefore, we can conclude that the pressure drop in the fen in this
scenario is almost exclusively because of the effect of water losses to ET. The low
hydraulic conductivity of the liner combined with the unsaturated conditions below
the liner effectively maintains the water within the shallow subsurface environment
without significant leakage losses.
For the next set of simulations (Steady-state case 2), K of the liner is lowered by
one order of magnitude to 1 6 10À10
m/s (shown as Liner II in Table 3) to
determine if this would restrict seepage losses and thereby divert more water to the
fen. The outcome is that the pressure in the fen is maintained above the threshold for
about 105 days (Figure 6), an increase of 17 days relative to using the Liner I. None
of the upland design changes have any significant impact on the pressure response.
As a final component of the liner sensitivity assessment (Steady-state case 3), the
liner K is raised by one order of magnitude from the base case to 1 6 10À8
m/s. The
long-term drought caused the pressure in the fen to drop below the critical value
Figure 5. Steady-state case 1. Pressure response in fen because of changes in design features
and using Liner I, Aquifer I properties. The horizontal grey line in this and subsequent
pressure vs. time graphs represents the threshold pressure defined by Price [15].
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12. within 5 days (not shown), indicating that this liner is far too permeable to maintain
water flow to the fen.
Steady-state case 4 examines the effect of increasing aquifer sand K to 1 6 10À4
m/s. Under long-term drought conditions, 112 days are required for the pressure in
the fen to drop below the critical value (Figure 7), an increase of 24 days relative to
the Aquifer I/Liner I case response. In this scenario the higher K of the aquifer sand
allows water to flow downslope more rapidly to the fen. Under this scenario the
longer liner (upland to fen surface area ratio of 3:1) also has a significant impact on
the pressure response, increasing the time to reach critical pressure to 176 days, an
increase relative to the base case of 64 days. The shorter liner (upland to fen surface
area ratio of 1:1) reduces the time to reach critical pressure to 106 days, a decrease
relative to the base case of 6 days.
These results indicate that the aquifer sand permeability is an important design
feature, and if it is too low, it may prevent water from reaching the fen quickly
enough to prevent a critical pressure drop there from ET losses during a drought.
Figure 7. Steady-state case 4. Pressure response in fen due to changes in design features and
using Liner II, Aquifer II properties.
Figure 6. Steady-state case 2. Pressure response in fen because of changes in design features
and using Liner II, Aquifer I properties.
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13. Modelling transient climate input
We have chosen to model a period (October 1997–2001) during which the most
severe drought on record occurred (1998). The model was run with daily climate
inputs. The steady state saturations, which were used as the initial condition for the
sensitivity analysis, were also used in the transient climate scenarios. Therefore, the
modelled fen is initially well-saturated, with ponded water on its surface. We chose
the month of October 1997 as the starting point for the simulation, because it is at
the end of a relatively wet period, when it is likely that real fens would also be well
saturated. The simulation period from October 1997 until March 1998 (onset of
drought) therefore allows the model some time to adjust the initial moisture
distribution so that it reflects the transient climate inputs more realistically.
Transient case 1 is based on the optimal materials as discerned above,
corresponding to Liner II (K ¼ 10À10
m/s) and Aquifer II (K ¼ 10À4
m/s). From
October 1997 to April 1998 the simulations show the fen has been sufficiently rewet
to include ponded water to a depth of about 0.1 m (Figure 8). In a field setting, this
would become frozen, and sublimation losses would be negligible. Snowmelt in April
drains quickly, and the effects of a water deficit then become marked during the very
dry summer of 1998. The steep decline on the water pressure is punctuated by a
major rainfall in July, but continues to decline until the end of October, when the
trend reverses and the pressure begins to rise, continuing to do so until the water
level recovers entirely to its spring maxima coinciding with snowmelt. The rise in
pressure over the winter period reflects groundwater input from the upland since
precipitation (snow) is stored at the surface. A similar pattern occurs in 1999 and
2000, although the degree of drying is much less, corresponding to smaller water
deficits in those years.
Changes in geometry do not substantially alter the pattern of water pressure,
except that the longer liner (upland to fen surface area ratio of 3:1) causes earlier
rewetting; and a shorter liner (upland to fen surface area ratio of 1:1) results in
Figure 8. Transient case 1. (a) NET Flux (mm) and (b) Transient pressure response to daily
climate inputs (rain, snowmelt, evaporation and transpiration) and using Liner II, Aquifer II
properties.
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14. incomplete recharge. The water pressure in the fen is therefore sensitive enough to
liner length to suggest that an upland to fen surface area ratio of 1:1 is inadequate,
even with the favourable material properties. Altering the slope of the upland and
liner has a relatively minor effect. The simulated water pressure in 1998 drops almost
to the threshold value by September, and remains there over the winter when the
plants are dormant. The low pressure at this time therefore has little consequence
because the plants’ water requirements are negligible.
Transient case 2 tested less optimal materials (higher permeability Liner I (10À9
m/s)). The drop in pressure over the course of the year (not shown) is substantially
more and the pattern of pressure is more erratic. In this case, the pressure falls
throughout the winter of 1998, because the higher hydraulic conductivity of the liner
does not retain water so effectively, and soil-water pressure in the peat never really
recovers for the duration of the simulation. The threshold conditions using Liner I,
therefore cannot be sustained in drought years, and represent the absolute upper
limit of liner K that could be used.
Discussion and conclusion
The results indicate that there are limitations to the construction of a fen system on a
post-mined landscape related to the availability of suitable materials. The assessment
was made on the basis of achieving a threshold level of wetness in fen peat when an
upland source area provides adequate seepage. Simulation modelling using local
climate inputs showed that the most important feature of such a system include a
liner of sufficiently low hydraulic conductivity (ideally 1 6 10À10
m/s) and a sandy
aquifer with sufficiently high hydraulic conductivity (10À4
–10À5
m/s). The main
geometric feature of design is that the upland to fen surface area ratio be greater than
or equal to 2:1. On the basis of transient simulation using daily estimates of P and
ET during the most severe drought on record, the above design maintained the
specified level of wetness for the growing season. The adequacy of this threshold can
be judged against local data for that same period. At undisturbed fen sites of the
Utikima Lake region the water table in fens dropped to 1.6 m below the surface
during 1998 [17]. This compares to a water table of *1.3 m in the current
simulations. Evidently, these natural sites can tolerate periods of drought more
extreme than we have set for a threshold (À1 m). It is noteworthy, however, that in
both this simulation and in the field study [17] the minimum water table
corresponded to a dormant period for plants (November), and that much of the
previous growing season experienced water pressures above the threshold specified
here.
The purpose of this study was to determine the optimal material properties and
system geometry that would sustain a certain level of wetness in fen peat that is
thought sufficient to reduce its oxidation rate, and provide a growth medium for fen
plants. As there are no such created fen systems to study, this hypothetical system
was constructed and the water flow and stores were modelled as a way of narrowing
down the design options rather than building by trial and error. There remains a
great deal of uncertainty. Foremost is the absence of any data against which the
simulations can be directly compared. The climate inputs have a range of certainty
from moderate (P) to less certain (ET). The role of interception is not considered.
The hydraulic characteristics range from reasonable estimates of saturated hydraulic
conductivity, to uncertainties associated with the water retention and unsaturated
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15. hydraulic conductivity functions. In particular, the water retention function of
disturbed peat material is poorly defined. Nevertheless, the design features suggested
by these simulations provide a reasonable starting point if a pilot system is to be
constructed.
The sensitivity analysis suggests that a low permeability liner is the key to
sustaining the requisite wetness conditions in the fen. Liner III (K ¼ 10À8
m/s) is
clearly inadequate for directing water laterally (Table 5). Liner I (K ¼ 10À9
m/s) can
do so, but the flow towards the fen is sufficiently slow (with Aquifer I sand) that
leakage through the liner is still significant enough that adding flow from an
extended upland (upland to fen surface area ratio of 3:1) makes no difference, since
the opportunity for vertical seepage losses are too great. If Liner I is all that is
available then its thickness should be increased. When liner material K is lowest
(Liner II K ¼ 10À10
m/s) and aquifer sand high (Aquifer II K ¼ 10À4
m/s) the effect
of an extended upland (Upland to Fen ratio of 3:1) becomes substantial (Table 5),
and the overall time to threshold condition increases by nearly 60% compared to the
base case geometry (upland to fen surface area ratio of 2:1). The above set of
analyses implies that a fen system with Liner II and Aquifer II properties offers the
most hope of sustaining threshold conditions during periods of drought.
Acknowledgements
Funds received from Albian Sands and the Cumulative Environmental Management
Association (CEMA) are gratefully acknowledged.
References
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the mining of metals and industrial minerals: A review of theory and practice, Environ. Rev.
10 (2002), pp. 41–71. DOI: 10.1139/A01-014.
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Ecol. Eng. 17 (2001), pp. 2–3, pp. 87–90.
[3] D. Woynilowicz, C. Severson-Baker, and M. Raynolds, Oil Sands Fever, The
Environmental Implications of Canada’s Oil Sands Rush, The Pembina Institute, Drayton
Valley, Alberta, November 2005.
[4] Alberta Environment, Guidelines for reclamation to forest vegetation in the Alberta oil
sands region. Conservation and reclamation information letter, C&R/IL/99-1. (1999). p. 5.
Available at http://www3.gov.ab.ca/env/protenf/landrec/documents/99-1.pdf.
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Table 5. Time for pressure 0.1 m below fen surface to drop below À100 cm during extreme
drought conditions (P ¼ 0 mm/y), from a condition of steady-state saturation produced by
the average surface flux (P-ET) of 179 mm/y.
Upland to
fen ratio 1:1
Upland to fen
ratio 2:1
Upland to fen
ratio 3:1
Liner I (10À9
m/s); Aquifer I (10À5
m/s) 88* 88* 88*
Liner II (10À10
m/s); Aquifer I (10À5
m/s) 105 105 105
Liner II (10À10
m/s); Aquifer II (10À4
m/s) 106 112 176
Liner III (10À8
m/s); Aquifer I (10À5
m/s) 5 5 5
*When liner thickness is doubled, the critical time was 93 days.
122 J.S. Price et al.
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