One of the world’s largest freshwater deltas (~4000 km2), the Peace-Athabasca Delta (PAD), is located at the convergence of the Peace and Athabasca rivers and Lake Athabasca in northern Alberta, Canada. Since the early 1970s, there has been increasing concern regarding the ecological impacts on the PAD after flow regulation of the Peace River began in 1968, decreased discharge in the Peace and Athabasca rivers as a result of hydroclimatic changes in Western Canada, and increased Athabasca River water usage by oil sands development to the south. This thesis is part of an ongoing, multi-disciplinary project assessing current and past hydrological and ecological conditions in the PAD. Research conducted in this thesis aims to better understand the processes controlling water balance of lakes in the PAD using mainly stable water isotope data collected from lakes and their input sources. Isotope data are used to describe and quantify hydrological processes for individual lakes (seasonal and annual) and across the delta and are supported by other chemical and hydrometric data. An isotopic framework in d18O-d2H-space is developed for the PAD using evaporation-flux-weighted local climate data, and isotopic data collected from a reference basin, lakes throughout the PAD, and lake input sources (i.e., snowmelt, rainfall, and river water). The framework is comprised of two reference lines, the Local Meteoric Water Line, which is based on measured isotopic composition of precipitation, and the Local Evaporation Line, which is based on modelled isotopic composition of reference points. Evaporation pan data is used to assess short-term variations in key isotopic reference values, which are important for addressing short-term changes in the isotopic signature of shallow basins. This framework is used in subsequent chapters including assessment of seasonal and annual water balance of two hydrologically-contrasting shallow lakes, and to quantify the impacts of flood water and snowmelt on a set of 45 lakes in spring 2003. Five years of isotope data using time-series analysis and the isotopic framework suggested that a perched (isolated) lake and its catchment (forest and bedrock) in the northern, relict Peace sector captured sufficient rain, snow, and runoff to maintain a relatively stable water balance, and also that a low-lying lake in the southern, active Athabasca sector was regularly replenished with river water in both spring and summer. Snowmelt and rainfall were found to have diluted the perched basin by an average of 16% and 28 % respectively, while spring and summer floods were found to almost completely flush the low-lying lake. Using the spring 2003 regional dataset, flooded lakes were separated from snowmelt-dominated lakes through use of suspended sediment concentrations, isotope data, and field observations. Application of an isotope mixing model translated d18O values into a range of replenishment amount by either river water or snowmelt, which compared well with hydrological conditions at the time of sampling and previously classified drainage types of the lakes. Spatial mapping of replenishment amounts illustrated flooding of much of the Athabasca sector due to ice-jams, except for two sub-regions isolated from flooding by artificial and natural northern diversion of flow from the Athabasca River. It is also shown that most of the relict landscape of the Peace sector was replenished by snowmelt except for a few low-lying lakes close to the Peace River and its tributaries. Overall, improved understanding of lake and regional hydrology in the PAD, especially the ability to quantify the affects of various lake inputs, will improve the ability to develop effective guidelines and management practices in the PAD as lakes respond to future changes in climate and river discharge.

This research investigated the system by which the social effects of oil sands development on Fort McMurray, a city in northeastern Alberta, are assessed and managed. The research focused on Social Impact Assessment (SIA), Strategic Environmental Assessment (SEA), and the work of an industry initiative, the Regional Issues Working Group (RIWG). The oil sands industry, which involves large, labour-intensive mining and drilling operations in a boom-bust cycle, places considerable pressure on Fort McMurray, a city of approximately 50,000 inhabitants and the only urban area within 350 km of the oil sands. The social effects experienced there include exorbitant housing prices, shortages in service industry labour, insufficient social services, at times, to assist individuals and families who can no longer cope with the difficult conditions in the area, and a variety of other negative effects. Sixteen key informant interviews were conducted with urban planners, municipal politicians, provincial employees, a spokesperson for one of the First Nations in the area, community NGOs, and oil sands industry representatives. Data from the interviews were combined with a literature review and a document analysis. A modified McKinsey 7S Integrated Management Framework was used as a structure for describing and analyzing the Social Effects Assessment and Management System (SEAMS) in Fort McMurray. The SEAMS was found to be weak in comparison to the needs of the community. Project-by-project assessment of oil sands development was found to downplay the cumulative nature of social effects. Furthermore, no legislation or regulation existed that demanded action based on the findings of SIA. As a result, mitigation and management of social effects was insufficient, often occurring only when it was directly in the interests of the oil sands industry. While government and industry have plans in place to resolve some of the negative social effects, their actions were criticized by informants as being uncoordinated, inconsistent and often ineffective. The findings indicate that a strategy for exploiting Alberta's oil sands is necessary. The project-by-project evaluation of oil sands development proposals is not addressing the important long-term and regional social issues that arise as a result of construction and operation of the mines and facilities. A tool recommended for incorporating resolutions to long-term, regional social effects into the development plan is SEA with an explicit Strategic Social Assessment component. This strategic assessment and planning process should be undertaken by a publicly-accountable government body empowered to rationalize the pace of oil sands development based on social, environmental and economic effects, and to coordinate long-term responses by government and industry.

One of the world’s largest freshwater deltas (~4000 km2), the Peace-Athabasca Delta (PAD), is located at the convergence of the Peace and Athabasca rivers and Lake Athabasca in northern Alberta, Canada. Since the early 1970s, there has been increasing concern regarding the ecological impacts on the PAD after flow regulation of the Peace River began in 1968, decreased discharge in the Peace and Athabasca rivers as a result of hydroclimatic changes in Western Canada, and increased Athabasca River water usage by oil sands development to the south. This thesis is part of an ongoing, multi-disciplinary project assessing current and past hydrological and ecological conditions in the PAD. Research conducted in this thesis aims to better understand the processes controlling water balance of lakes in the PAD using mainly stable water isotope data collected from lakes and their input sources. Isotope data are used to describe and quantify hydrological processes for individual lakes (seasonal and annual) and across the delta and are supported by other chemical and hydrometric data. An isotopic framework in d18O-d2H-space is developed for the PAD using evaporation-flux-weighted local climate data, and isotopic data collected from a reference basin, lakes throughout the PAD, and lake input sources (i.e., snowmelt, rainfall, and river water). The framework is comprised of two reference lines, the Local Meteoric Water Line, which is based on measured isotopic composition of precipitation, and the Local Evaporation Line, which is based on modelled isotopic composition of reference points. Evaporation pan data is used to assess short-term variations in key isotopic reference values, which are important for addressing short-term changes in the isotopic signature of shallow basins. This framework is used in subsequent chapters including assessment of seasonal and annual water balance of two hydrologically-contrasting shallow lakes, and to quantify the impacts of flood water and snowmelt on a set of 45 lakes in spring 2003. Five years of isotope data using time-series analysis and the isotopic framework suggested that a perched (isolated) lake and its catchment (forest and bedrock) in the northern, relict Peace sector captured sufficient rain, snow, and runoff to maintain a relatively stable water balance, and also that a low-lying lake in the southern, active Athabasca sector was regularly replenished with river water in both spring and summer. Snowmelt and rainfall were found to have diluted the perched basin by an average of 16% and 28 % respectively, while spring and summer floods were found to almost completely flush the low-lying lake. Using the spring 2003 regional dataset, flooded lakes were separated from snowmelt-dominated lakes through use of suspended sediment concentrations, isotope data, and field observations. Application of an isotope mixing model translated d18O values into a range of replenishment amount by either river water or snowmelt, which compared well with hydrological conditions at the time of sampling and previously classified drainage types of the lakes. Spatial mapping of replenishment amounts illustrated flooding of much of the Athabasca sector due to ice-jams, except for two sub-regions isolated from flooding by artificial and natural northern diversion of flow from the Athabasca River. It is also shown that most of the relict landscape of the Peace sector was replenished by snowmelt except for a few low-lying lakes close to the Peace River and its tributaries. Overall, improved understanding of lake and regional hydrology in the PAD, especially the ability to quantify the affects of various lake inputs, will improve the ability to develop effective guidelines and management practices in the PAD as lakes respond to future changes in climate and river discharge.

This research investigated the system by which the social effects of oil sands development on Fort McMurray, a city in northeastern Alberta, are assessed and managed. The research focused on Social Impact Assessment (SIA), Strategic Environmental Assessment (SEA), and the work of an industry initiative, the Regional Issues Working Group (RIWG). The oil sands industry, which involves large, labour-intensive mining and drilling operations in a boom-bust cycle, places considerable pressure on Fort McMurray, a city of approximately 50,000 inhabitants and the only urban area within 350 km of the oil sands. The social effects experienced there include exorbitant housing prices, shortages in service industry labour, insufficient social services, at times, to assist individuals and families who can no longer cope with the difficult conditions in the area, and a variety of other negative effects. Sixteen key informant interviews were conducted with urban planners, municipal politicians, provincial employees, a spokesperson for one of the First Nations in the area, community NGOs, and oil sands industry representatives. Data from the interviews were combined with a literature review and a document analysis. A modified McKinsey 7S Integrated Management Framework was used as a structure for describing and analyzing the Social Effects Assessment and Management System (SEAMS) in Fort McMurray. The SEAMS was found to be weak in comparison to the needs of the community. Project-by-project assessment of oil sands development was found to downplay the cumulative nature of social effects. Furthermore, no legislation or regulation existed that demanded action based on the findings of SIA. As a result, mitigation and management of social effects was insufficient, often occurring only when it was directly in the interests of the oil sands industry. While government and industry have plans in place to resolve some of the negative social effects, their actions were criticized by informants as being uncoordinated, inconsistent and often ineffective. The findings indicate that a strategy for exploiting Alberta's oil sands is necessary. The project-by-project evaluation of oil sands development proposals is not addressing the important long-term and regional social issues that arise as a result of construction and operation of the mines and facilities. A tool recommended for incorporating resolutions to long-term, regional social effects into the development plan is SEA with an explicit Strategic Social Assessment component. This strategic assessment and planning process should be undertaken by a publicly-accountable government body empowered to rationalize the pace of oil sands development based on social, environmental and economic effects, and to coordinate long-term responses by government and industry.

Diatom analyses were carried out on sediment cores collected from two low-lying, closed-drainage basins (PAD 9 - 58º46. 46?N, 111º19. 48?W; PAD 12 - 58º57. 29?, 111º19. 74?) in the Peace sector of the Peace-Athabasca Delta (PAD), Alberta, Canada, to provide >1000 year long records of hydro-ecological change. Results from diatom analyses were compared with macrofossil and stable isotope records from the same cores and assessed within the framework of an Athabasca River headwater climate record inferred from isotope dendroclimate data. Results from PAD 9 and PAD 12 sediment cores indicated closed-drainage conditions during the Medieval Warm Period (MWP) and the post-Little Ice Age and high water conditions during the Little Ice Age (LIA). High water levels at PAD 9 and PAD 12 reflected high water conditions on Lake Athabasca and the Rivière des Rochers or possibly the Peace River during the LIA (~AD 1600-1900). High water conditions were also observed at low-lying sites in the central and southern regions of the PAD (PAD 31 and PAD 37), and corresponded with evidence of high streamflows on the North Saskatchewan River. In contrast, desiccation evident at PAD 5, a site largely isolated from river influence, reflected atmospherically dry conditions during the LIA. Consistent with changes observed at PAD 5, sediment records at PAD 15, an oxbow lake off the Revillion Coupé, demonstrated low flood frequency during the early to mid-1700s. Increased water levels evident at low-lying sites located in proximity to the central open-drainage network of lakes and rivers were likely due to higher flows on the Athabasca River and potentially on the Peace River. High flows on rivers of the PAD may be attributed to snowmelt-dominated runoff during the LIA relative to the rainfall-dominated runoff during MWP (prior to ~AD 1600) and the post-LIA period (~AD 1900 to present).

Periodic flooding has been widely believed to serve an important role in maintaining water levels and productivity of aquatic basins in floodplain landscapes. Here, I analyze four basins of contrasting flood frequencies (one through-flow, one pulse-flooded, two non-flooded) and two adjacent river sites in the PAD were sampled during the open-water season of 2007 and spring of 2008 to characterize linkages between hydrological processes (using O and H stable isotopes) and limnological conditions, and to assess how these linkages affect trophic interactions involving the aquatic flora and fauna (using C and N stable isotopes). The water balance and water chemistry of the through-flow basin was dominated at all times by the input of river water which reduced concentrations of nutrients and ions. In contrast, evaporation played an important role in the water balance and concentrated nutrients and ions in the non-flooded basins. Surprisingly, pulse-flood events had short-lived effects on the water balance and carbon stable isotopic signatures of biota. Hydrological and limnological conditions in the pulse-flooded basin were similar to those of the river water shortly after spring flooding. After flooding, evaporation caused rapid increase of δ18O of the water comparable to patterns observed in the non-flooded basins, but recovery of water chemistry variables was delayed. In the non-flooded and pulse-flooded basins, δ13CDIC declined due to atmospheric CO2 invasion under conditions of high primary productivity and pH that generated strong kinetic fractionation. This decline in δ13CDIC values produced the opposite effect compared to when photosynthesis occurs under non-limiting carbon conditions, as occurred in the through-flow basin. This feature provides important new knowledge to improve paleolimnological interpretation of δ13C values of organic matter in sediment cores to track past changes in flooding regimes. Importantly, this study shows that pulse floods exert short-lived transient (~1-2 months) effects of the water balance and carbon dynamics of aquatic food-webs and do not elevate aquatic production, but exert longer lasting (at least an entire open-water season) on water chemistry conditions. This contrasts with previous beliefs that the effects of pulse flooding are more profound and longer lasting.

Increased land use intensity has adversely affected aquatic ecosystems within Canada. Activities that occur over the landscape are individually minor but collectively significant when added to other past, present, and reasonably foreseeable future actions, and are defined as cumulative effects. Existing approaches to cumulative effects assessment for river systems within Canada are ineffective. This thesis aims to improve the practice of cumulative effects assessment by evaluating current methodology for linking landscape change and river response over a large spatiotemporal scale. As part of this goal, I offer a framework for better incorporating science into current practices for cumulative effects assessment. The framework addresses the challenges involved in cumulative effects assessment, such as defining appropriate spatial and temporal scale, complex ecological and hydrologic pathways, predictive analysis, and monitoring. I then test the framework over a large spatiotemporal scale using a case study of the lower reaches of the Athabasca River Basin, Alberta. Three objectives are addressed: 1) changes in land use and land cover in the lower ARB for several census dates (1981, 1986, 1991, 1996, 2001) between 1976 (historic) and 2006 (current day) are identified; 2) linkages between landscape change and river water quality and quantity response are evaluated; and 3) results of the different methods used to link landscape stressors with stream responses are compared. Results show that the landscape has changed dramatically between 1976 and 2006, documented by increases in forest harvesting, oil sands developments, and agricultural intensity. Secondly, results suggest that linear regression tests combined with regression trees are useful for capturing the strongest associations between landscape stressors and river response variables. For instance, water abstraction and agricultural activities have a significant impact on solute concentrations. This suggests that water abstraction and agriculture are important indicators to consider when conducting a watershed cumulative effect assessment on a similar spatiotemporal scale. The thesis has strong implications for the need for improved water quality and quantity monitoring of Canada‟s rivers. The research provides a means of identifying appropriate tools for improved watershed cumulative effects assessment for scientists and land managers involved in the environmental impact assessment process and protection of Canada‟s watersheds.

Periodic flooding has been widely believed to serve an important role in maintaining water levels and productivity of aquatic basins in floodplain landscapes. Here, I analyze four basins of contrasting flood frequencies (one through-flow, one pulse-flooded, two non-flooded) and two adjacent river sites in the PAD were sampled during the open-water season of 2007 and spring of 2008 to characterize linkages between hydrological processes (using O and H stable isotopes) and limnological conditions, and to assess how these linkages affect trophic interactions involving the aquatic flora and fauna (using C and N stable isotopes). The water balance and water chemistry of the through-flow basin was dominated at all times by the input of river water which reduced concentrations of nutrients and ions. In contrast, evaporation played an important role in the water balance and concentrated nutrients and ions in the non-flooded basins. Surprisingly, pulse-flood events had short-lived effects on the water balance and carbon stable isotopic signatures of biota. Hydrological and limnological conditions in the pulse-flooded basin were similar to those of the river water shortly after spring flooding. After flooding, evaporation caused rapid increase of δ18O of the water comparable to patterns observed in the non-flooded basins, but recovery of water chemistry variables was delayed. In the non-flooded and pulse-flooded basins, δ13CDIC declined due to atmospheric CO2 invasion under conditions of high primary productivity and pH that generated strong kinetic fractionation. This decline in δ13CDIC values produced the opposite effect compared to when photosynthesis occurs under non-limiting carbon conditions, as occurred in the through-flow basin. This feature provides important new knowledge to improve paleolimnological interpretation of δ13C values of organic matter in sediment cores to track past changes in flooding regimes. Importantly, this study shows that pulse floods exert short-lived transient (~1-2 months) effects of the water balance and carbon dynamics of aquatic food-webs and do not elevate aquatic production, but exert longer lasting (at least an entire open-water season) on water chemistry conditions. This contrasts with previous beliefs that the effects of pulse flooding are more profound and longer lasting.

A study of the Millennium and Eagle Point basement-hosted deposits was conducted to obtain a comprehensive understanding of the alteration in these two atypical uraniferous systems and to apply these findings in formulating effective exploration strategies. In addition, an investigation of the Wheeler River “apparently barren” sandstone-hosted alteration system was conducted to provide insights into the critical events needed in order to form sandstone-hosted unconformity-related deposits. At Millennium, the atypical alteration halo, wherein the inner chlorite halo is much smaller than other basement-hosted deposits, is the result of pervasive muscovite alteration of the basement rocks by Na-K-Fe basinal brines during the pre-ore stage at ca. 250°C. As alteration of the basement rocks progressed, the basinal brines acquired Ca, Fe and Mg while creating up to 20% voids in the basement rocks. Prior to the mineralizing event, the chemically modified basinal fluids formed a minor Fe-rich chamoisite halo that demarcates a redox front during the ca. 1590 Ma syn-ore stage, where uranium ore was precipitated. At Eagle Point, the atypical alteration halo, wherein dolomite and calcite alteration is more significant than other basement-hosted deposits, is the result of more intense pre-Athabasca Basin alteration. The Eagle Point deposit is also distinct by significant late remobilization of primary uraninite into secondary structures that occurred at ca. 535 Ma. At the Wheeler River “apparently barren” alteration system, the critical factor for the lack of uranium mineralization in the sandstone is the temporal relationship between the different fluids with the uranium-bearing oxidized basinal fluids present prior to the reduced chemically modified basinal fluids and reduced basement fluids. However, the possibility of a small basement-hosted uranium deposit at Wheeler River cannot be excluded because the sudoite-producing basement fluids may represent basinal brines that reacted with basement lithologies to become reducing and Mg-rich, and therefore may have precipitated uraninite during this process. The results of this study support the genetic model in which basinal fluids were likely the source of uranium deposits and that the basement fluids were unlikely significant sources of uranium in sandstone-hosted deposits. / Thesis (Ph.D, Geological Sciences & Geological Engineering) -- Queen's University, 2009-09-30 14:49:03.688

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