Lower Peace River Research Articles

Effects of regulation on open‐water flows in the lower Peace River, Canada, and implications for the recharge of Peace‐Athabasca Delta basins

AbstractDownstream impacts of large hydropower dams are often neglected or underestimated, especially for areas situated at long distances from a dam. Naturalization of the flow hydrograph is an important step in assessing hydro‐ecological and socio‐economic impacts of regulation. Using reservoir inflows, a recently developed, lagged‐flow naturalization method is applied to the lower portion of the regulated Peace River, which forms the northern boundary of the Peace‐Athabasca Delta (PAD). The PAD is a Ramsar wetland of international importance that depends on overland flooding for recharge of its high‐elevation or “perched” basins. Such flooding can be caused by ice jams during the spring breakup of the ice cover or by exceptionally high runoff during open‐water flow conditions. Herein, the focus is on the latter type of event and the resulting recharge of basins located within the Peace sector of the PAD. For the period 1972–2017, regulation has reduced open‐water flow peaks by ~4100 m3/s on average, while limiting the possibility of overbank flooding from the Peace River during the summer. Consistent with earlier findings on spring breakup flows, naturalized open‐water peaks do not exhibit a temporal trend. Recharge of non‐perched basins can also occur with moderately high flows that cause no overland flooding but generate flow reversals in Peace River tributaries. In turn, this mechanism can deliver river water to various basins either directly or via connecting channels. Our results show that flow‐based variables that index the hydrological sustenance of non‐perched basins have been significantly reduced by regulation.

Naturalizing the freezeup regimes of regulated rivers and exploring implications to spring ice‐jam flooding

AbstractNaturalization of the flow hydrograph and ice regime is a key step in assessment of ecological and socioeconomic impacts of regulation across large portions of Europe, Asia and North America, where many rivers are dammed for hydropower generation. Building on previous naturalization of early‐freshet flows that influence the nature of breakup and jamming events, novel methodology is developed to estimate natural freezeup flows and thence determine associated water levels, also known to influence subsequent breakup events. Using reservoir inflows, the new methodology is applied to the lower portion of the regulated Peace River, Canada, which forms the northern boundary of the Peace‐Athabasca Delta (PAD), a Ramsar wetland of international importance that partially depends on spring ice‐jam flooding for recharge of its high‐elevation, or “perched” basins. The PAD provides habitat for numerous aquatic, terrestrial and avian species and is vital to the maintenance of indigenous culture and lifeways. Naturalized freezeup levels in the lower Peace River are shown to be nearly always lower than corresponding regulated values, with the difference averaging ~1.6 m. Consistent with known physics of river ice breakup processes, the present results suggest that ice‐jam flood frequency would likely have been greater under natural conditions. Though potentially adverse from the ecological standpoint, reduction of spring ice‐jam flooding can benefit riverside communities. Implications of the present results to and comparison with, other Canadian and international rivers are discussed.

Climate change impacts on Peace River ice thickness and implications to ice-jam flooding of Peace-Athabasca Delta, Canada

Major ice jams forming in lower reaches of the Peace River during spring breakup have been identified as the main agents of flooding and replenishment of perched basins of the Peace–Athabasca Delta, one of the world's largest inland freshwater deltas that supports a dynamic and valuable ecosystem. The paucity of ice jamming in the lower Peace River following construction of the Bennett Dam and the potential impacts of climate change have raised concerns regarding habitat degradation. One of the factors controlling ice-jam formation is the thickness of the winter ice cover, which may decrease in the future as a result of climatic warming, known to be most pronounced in northern parts of the globe and during the winter season. Using downscaled daily output from six Global Climate Models under two Representative Concentration Pathway scenarios, ice thickness is calculated for the years 1950 to 2100. Comparisons of monthly model-generated air temperatures and winter snowfall to historical data at nearby Fort Chipewyan indicate satisfactory agreement in terms of both magnitude and variability. Future projections show that under the highest emission scenario, average thickness decreases by about 0.2 m between the 1980s and the 2050s; and by an additional 0.1 m by the 2080s. Projected probability distributions of ice thickness point to increased incidence of thermal breakup, potentially reducing the already-low chances of ice-jam flooding. At the same time, a need for enhanced ice thickness monitoring is identified, aiming to develop a database of annual thickness values at selected sites within the lower reach of Peace River.

Habitat Suitability Modeling and Mapping to Assess the Influence of Freshwater Withdrawals on Spatial Distributions and Population Numbers of Estuarine Species in the Lower Peace River and Charlotte Harbor, Florida

AbstractThe effects of potential reductions of freshwater inflow were evaluated for the lower Peace River and its largest tributary, lower Shell Creek, which flow into the Charlotte Harbor estuary in southwest Florida. Habitat suitability modeling (HSM) and mapping of fish and invertebrate species life stages were used to seasonally predict changes in spatial distributions and population numbers associated with simulated freshwater withdrawals. Seasonal salinity grids and temperature grids derived from values predicted by hydrodynamic modeling (2007–2014) were similar between baseline (i.e., flows not affected by water withdrawals) and minimum flows (flows associated with water withdrawals). Depth grids, bottom type grids, and seasonal dissolved oxygen grids were held constant between the two scenarios. Seasonal habitat suitability models were applied to 28 fish and invertebrate species life stages with affinities for low or moderate salinity. Salinity was the most significant factor in seasonal models for species life stages. The seasonal HSM maps produced showed that spatial distributions were similar between baseline and minimum flows for each species life stage. Most seasonal estimates of population numbers under minimum flows were less than the estimates for the baseline condition, indicating some effect on population numbers associated with flow reductions. Reductions in population numbers under minimum flows ranged from 0.3% to 21.0%, with 3 out of 28 seasonal comparisons indicating losses >15% and 12 comparisons indicating losses between 5% and 15%. Although other factors related to freshwater inflow can also influence species abundance and distribution, these results demonstrate how output from hydrodynamic modeling can be applied to HSM analyses and mapping to estimate spatial changes in habitat areas and population numbers for the life stages of selected fish and invertebrate species in relation to changes in salinity distributions, which can be used to identify areas of an estuary that are particularly susceptible to the effects of inflow reductions.

Commentary on “Past variation in Lower Peace River ice-jam flood frequency” by Wolfe et al. (2020)

In contrast to a large body of scientific literature that is based on empirical data and physically based and mathematical analyses, Wolfe et al. (2020) cited proxy-based paleolimnological evidence and argued that the regulation of Peace River has not played a role in the reduced incidence of large ice-jam floods. Such events are essential to the sustenance of perched basins located in the Peace Sector of the Peace–Athabasca Delta. Herein, the arguments advanced by Wolfe et al. (2020) are critically examined and shown to be unconvincing. Relevant literature indicates that a drying trend was first noticed after construction of the Bennett Dam. It is shown, moreover, that the belatedly questioned Traditional Knowledge and Historical ice-jam flood record is a reliable source of information, at least with respect to large floods, which are crucial to perched-basin replenishment. Detailed examination of the Wolfe et al. (2020) magnetic susceptibility (MS) profiles and their interpretation points to serious inconsistencies and leads to a renewed recommendation for coring perched, rather than readily flooded, basins in the future. It is also recommended that the oxbow lakes cored nearly two decades ago be revisited to obtain updated MS profiles. Deficiencies in the interpretation of inferred isotopic-composition time series of three perched basins suggest that all factors influencing such environmental variables be considered before drawing conclusions regarding the frequency of past floods.

Response to Commentary by Beltaos and Peters on: “Past variation in Lower Peace River ice-jam flood frequency” by Wolfe et al. (2020)

Response to Commentary by Beltaos and Peters on: “Past variation in Lower Peace River ice-jam flood frequency” by Wolfe et al. (2020)

Hydrodynamic Simulations of Charlotte Harbor and its Major Tributaries in Florida Using a Dynamically Coupled 3D – 2DV model

Hydrodynamics, salinity transport processes, and thermodynamics in Charlotte Harbor and its major tributaries in Florida, USA were simulated using a coupled three-dimensional (3D) and laterally averaged two-dimensional (2DV) hydrodynamic model named UnLESS, in support of the re-evaluation of minimum freshwater inflows for two water bodies in the system, namely the lower Peace River (LPR) and lower Shell Creek (LSC). The UnLESS model involves a dynamic and two-way coupling of the 3D unstructured Cartesian grid model UnLESS3D (Chen, 2011) with the laterally averaged model LAMFE (Chen, 2003a) using a semi-implicit scheme named the free-surface correction (FSC) method (Chen, 2003b.)The simulation period was January 2013 through August 2014, during which best real-time data of water elevation, current, salinity, and temperature at five measurement stations within the simulation domain were available. Comparisons of model results with these real-time field data show that UnLESS is capable of simulating hydrodynamics, salinity transport processes, and thermodynamics well in the Charlotte Harbor estuary. Good matches of model results with measured data suggest that both estimated ungauged flows and downstream boundary conditions were reasonable. Major physical characteristics in the Charlotte Harbor system are correctly simulated by the UnLESS model. It is demonstrated that the dynamically coupled 3D-2DV model UnLESS is robust and very efficient for complex systems such as Charlotte Harbor, which has a large waterbody with islands and several narrow and meandering tributaries.

Past variation in Lower Peace River ice-jam flood frequency

Opposing interpretations of Lower Peace River ice-jam flood frequency data sets are at the centre of identifying causes of reduced freshwater availability in the Peace-Athabasca Delta (northern Alberta), a Ramsar Wetland of International Importance and a major contributor to Wood Buffalo National Park’s listing as a UNESCO World Heritage Site. Recently, conclusions drawn from statistical inference of traditional knowledge and historical observation sources suggested that flood frequency was accelerating during 1880–1967 and then declined coincident with hydroelectric regulation of Peace River flow since 1968 that altered the river’s hydrograph. In contrast, prior paleolimnological measurements of laminated sediments from oxbow lakes proximal to the Peace River have, along with alternate presentation of the traditional knowledge and historical observation sources, identified flood frequency was in decline for decades preceding river regulation due to climate change since the Little Ice Age. Here we revisit these data sets and, specifically, review their inherent uncertainties to assess their value and limitations. The notion of increasing versus decreasing flood frequency in the decades preceding river regulation (1880–1967) is tested using previously published paleohydrological records from perched lakes in the delta. Those records from lakes most proximal and sensitive to changes in the flow regime of the Peace River show increasing influence of lake evaporation during 1880–1967, consistent with long-term decline in flood frequency. Reconciling uncertainties of multiple lines-of-evidence and their findings should inform decisions by UNESCO on the World Heritage status of Wood Buffalo National Park and execution of the park’s federally funded Action Plan. New paleolimnological studies that have recently been launched will continue to probe the hydrological history of the Peace-Athabasca Delta to serve as a foundation for effective stewardship.

Modeling and Mapping to Assess Spatial Distributions and Population Numbers of Fish and Invertebrate Species in the Lower Peace River and Charlotte Harbor, Florida

AbstractCatch per unit effort (CPUE) was computed from fisheries‐independent monitoring data collected from 1996 through 2013 in the lower Peace River and Charlotte Harbor, Florida. Seasonal habitat suitability modeling (HSM) based on delta‐gamma generalized additive models was prepared for eight fish and invertebrate species life stages with affinities for either low or moderate salinities. Using a geographic information system, habitat maps were created from monitoring data for temperature, salinity, dissolved oxygen, depth, and bottom type in the study area. Gear‐corrected CPUEs derived from HSM were applied to corresponding habitat grid cells. Seasonal HSM maps were then created, depicting the spatial distribution and relative abundance for early juvenile, juvenile, and adult life stages. By overlaying Optimum abundance zones from each HSM map onto corresponding salinity grids, the preferred ranges of salinity were found to be similar between seasons for each of six estuarine‐resident species life stages. This implies that each resident species occupies a unique salinity range in the river and estuary, which varies little between seasons. During the summer wet season, the geographic ranges occupied by each resident species life stage expanded in response to increased inflow, while the preferred salinity ranges occupied were similar between seasons. However, this was not the case for the two estuarine‐transient species (Red Drum Sciaenops ocellatus and Spot Leiostomus xanthurus), which tended to utilize different salinity ranges between seasons. Habitat‐based population estimates were prepared for each species life stage by using the predicted CPUE grids used to create the HSM maps. The demonstrated methods support ecosystem‐based fishery management and management of freshwater inflow to tidal rivers.

Ice-jam flood regime of the Peace-Athabasca Delta: Update in light of the 2014 event

Major ice jams forming in the lower reaches of Peace River during the spring breakup of the ice cover have been identified as the main agents of flooding and replenishment of the perched basins of Peace–Athabasca Delta, one of the world's largest inland freshwater deltas. The paucity of ice jamming in the lower Peace River following construction of the Bennett Dam (1968) and the potential impacts of climate change have raised concerns regarding habitat degradation. The most recent ice-jam flood, which occurred in 2014, was only the fifth in the post-regulation period and the first since 1997. Despite the sizeable number of years in the regulation period, conventional estimates of flood frequency are shown to be uncertain, but become robust when based on the slope of the cumulative number of floods. The evolution of ice breakup in 2014 was in full accord with previously postulated mechanisms for the flat reach of Peace River, which extends for several hundred kilometres above its mouth. An updated examination of historical hydrometric data at the WSC Peace Point gauge took into account the years 2003–2018, extending the record of the regulation period by 50%. The analysis further confirmed and fine-tuned physically based predictions of the effects of the freezeup level, the breakup flow, the thickness of the winter ice cover, and the accumulated degree-days of thaw on the incidence of ice-jam flooding. Commercially motivated reduction of freezeup flows in recent years likely contributed to the occurrence of the 2014 flood. Total winter snowfall at an index station appears to have reversed a pre-2000 decreasing trend, but its benefit to breakup flow may be moderated by increased incidence of mid-winter thaws.

The 2014 ice–jam flood of the Peace-Athabasca Delta: Insights from numerical modelling

Major ice jams forming in the lower reaches of Peace River during the spring breakup of the ice cover are the main agents of flooding and replenishment of the Peace–Athabasca Delta ecosystem. Their paucity following construction of the Bennett Dam (1968) and the potential impacts of climate change have raised concerns regarding habitat degradation. The most recent ice-jam flood, which occurred in 2014, was the fifth in the post-regulation period. Relative to previous occasions, the 2014 event was monitored in considerable detail. Unusually complete water level recordings at Delta hydrometric stations, high-water-mark elevations, and aerial observations furnish adequate quantitative evidence for application of numerical models. Ice-jam modelling capability is essential to quantification of flow magnitudes that help replenish the Delta and can facilitate assessment of climate-change impacts on flood frequency and development of adaptation strategies. Following a brief chronology of the 2014 ice breakup in the lower Peace River and presentation of key hydrometric data, the user-friendly, public-domain model HEC-RAS is briefly described and its setup for the lower Peace River outlined. It is then calibrated and validated on two ice jam configurations that occurred on distinct dates. Application of the calibrated model to different ice-jam scenarios indicated that jams of moderate, rather than extreme, length are more effective in flooding of the Delta.

Frequency of ice-jam flooding of Peace-Athabasca Delta

Major ice jams that occasionally form in lower Peace River generate extensive flooding, which helps replenish the perched basins of Peace-Athabasca Delta, a Ramsar wetland of international importance and a UNESCO World Heritage Site. This complex and dynamic ecosystem has experienced prolonged dry periods since the late 1960s, coincident with the construction of the W.A.C. Bennett hydroelectric dam in British Columbia. Physically-based and paleolimnological studies differ with respect to the impact of regulation on flood frequency. This issue is examined herein, based entirely on the historical record of observed ice-jam flood events.

Subsistence, regional planning and the cultural carrying capacity of First Nations in Alberta, Canada

This paper presents the results of the Lower Peace River Environmental Livelihoods Assessment that was carried out by the Lubicon Lake, Beaver, Tallcree and Little Red River Cree First Nations of A...

Hydrodynamics of storage release during river ice breakup

The breakup of the ice cover in cold-region rivers is a brief but seminal period of their hydrologic regime, with important ecological and socio-economic implications. The main driver of ice breakup processes is the flow discharge hydrograph. It is generated by runoff from snowmelt and rainfall but can be modified by rapid release of water from storage as the ice cover recedes by ablation and mechanical breaking up. Despite its potential importance, there is very limited quantitative information concerning the hydrodynamic processes that control storage release during ice breakup in rivers, while the issue of climate change underscores the need for improved understanding of the relevant mechanisms. Quantitative analysis for assumed prismatic channels shows that ablation and sustained ice dislodgment and breaking can cause significant flow enhancement via storage release. The latter process is far more dynamic than ablation and, under certain conditions, may lead to formation of a self-sustaining wave (SSW). Analytical results are applied to natural stream conditions, using the Lower Peace River as a case study. Observed rates of ice recession typically indicate ice melt as the dominant process. A rare occurrence of rapid ice breaking over hundreds of kilometres (2014) indicated partial agreement with the SSW concept and revealed that discrepancies may arise from the characteristic irregularity of rivers. Impacts on storage release by climate-driven changes to river ice regimes are examined, along with their implications to ice-jam formation and associated flooding.

Comparing the impacts of regulation and climate on ice-jam flooding of the Peace-Athabasca Delta

The Peace-Athabasca Delta (PAD) in northern Alberta is one of the world's largest inland freshwater deltas, home to large populations of waterfowl, muskrat, beaver, and free-ranging wood bison. Following construction of the Bennett Dam in the late 1960s, a paucity of ice-jam flooding in the lower Peace River has resulted in prolonged dry periods and considerable reduction in the area covered by lakes and ponds that provide habitat for aquatic life in the PAD region. Past studies have shown that both regulation and climate have contributed to the drying trend, via increased freezeup levels and reduced breakup flows, respectively. However, it has not so far been possible to assess the relative impacts of these two factors. This question is addressed herein by developing quantitative relationships based on the concept of conditional probability. The new methodology is first tested against observed frequencies of ice-jam floods both before and after regulation; it is subsequently applied to quantify the effects of climate and of regulation on the post-regulation reduction in ice-jam flood frequency. The results indicate that both factors have contributed significantly to the drying of the PAD, with regulation having had the more pronounced effect. Complications that may arise from secondary effects of regulation on breakup flows or of climate on freezeup levels are discussed and quantified. It is shown that such effects do not alter the overall conclusions of the paper.

Climate and vegetation change during the twentieth century in the lower Peace River district, northern Alberta, Canada

A 96-yr climate record (1908—2004), historical descriptions, multiyear (1950, 1964, 1978, 1994) lake-surface area measurements, and 1950 and 2004 physiognomically based vegetation maps were compiled to assess vegetation change in the Fox Lake area (4248 ha) within the lower Peace River district of northern Alberta. A climatic warming trend ( r = 0.615, P < 0.001; 0.35°C/decade) was evident during the twentieth century, with peak precipitation occurring from 1970 to 1990. Five major wet—dry cycles, based on net water balance values (precipitation minus potential evaporation), were evident with peaks occurring at about 17(±3) year intervals. Each cycle became slightly less arid than the previous until the mid-1990s. Deciduous forests dominated upland sites in 2004, whereas deciduous shrub and juvenile tree stands comprised 78% in 1950. Total wetland area remained relatively constant between 1950 and 2004, but less meadow and more standing water were present in 2004. Lake-surface area changes suggested that wetlands were recharged by precipitation rather than floodwaters from the nearby Peace River. Low water availability and historical descriptions suggest grassland-dominated parkland-like vegetation occurred in the study area during the early part of the twentieth century, with upland shrubs replacing grasslands by 1950. Increased atmospheric water availability rather than cessation of aboriginal burning or natural fires was considered responsible for increased forest abundance after 1945. Greater aridity in response to future global warming could reduce the abundance of forests in the lower Peace River district, and shift the regional climate from a boreal to a grassland-dominated parkland climatic regime.

Field studies of ice breakup and jamming in lower Peace River, Canada

Abstract Since the late 1960s, a paucity of ice-jam flooding in the lower Peace River has resulted in prolonged dry periods and considerable reduction in the area covered by lakes and ponds that provide habitat for aquatic life in the Peace–Athabasca Delta region. To help identify the causes of this trend and assess future conditions under a changing climate, a field observation program was conducted during 1999–2003. Limited data were also obtained during a significant event in 2007. This program has furnished the first detailed documentation of ice processes in the lower Peace. Though focusing on the breakup period, relevant antecedent conditions were also documented. Freezeup often involves formation of thickened ice covers, which lead to high freezeup stages and potentially to enhanced growth of the solid-ice layer during the winter. Ice decay prior to breakup can be moderate to severe, and is manifested in saturation and candling. The type of observed breakup ranged from essential melt-out in 2000, to occasional jamming upstream of the delta reach in 2003, and to a moderate delta flood in 2007. The field observations and measurements, including the only ice jam profile that has been measured in the lower Peace, are shown to be consistent with current physical understanding of breakup and jamming processes. The main factors conducive to ice-jam flooding are identified and their relative importance is assessed using physically-based breakup criteria. Breakup patterns are shown to be strongly influenced by the very low slope of the river, which amplifies the importance of waves generated by ice jam releases.

Simulating Hydrodynamics in the Upper Charlotte Harbor and its Major Tributaries in Florida

Charlotte Harbor is one of major estuaries in Florida. The upper portion of the estuary receives freshwater inflows mainly from the Peace and Myakka Rivers. To study the hydraulic interactions between the Upper Charlotte Harbor (UCH) and its major tributaries, a multi-block model was used to simulate hydrodynamics and salinity transport processes in a simulation domain that includes the UCH, the Lower Peace River (LPR), the Lower Myakka River (LMR), the Shell Creek, and a portion of the Myakkahatchee Creek. In the modeling study, the simulation domain is split into a 3D simulation block and several 2DV blocks. The 3D block includes the UCH and the most downstream portions of the LPR and LMR, while the 2DV blocks contain the rest of the tributaries. All the blocks are patched together without any overlaps. The coupled model solves 3D RANS equations for the 3D block, but laterally averaged RANS equations for the 2DV blocks that consist of narrow and braided tributaries. Both 3D and 2DV sub-models use an efficient semi-implicit, flux-based finite difference method. The dynamic coupling is facilitated using a free-surface correction method, in which matrixes for the water surface correction in both the 3D and 2DV sub-domains are solved simultaneously after they are merged together. Model simulations demonstrated that the multi-block model is an efficient tool for simulating hydrodynamics in a very complex environment and the model application to the LPR-LMR-UCH system is successful.

Hydro‐climatic impacts on the ice cover of the lower Peace River

AbstractSince the late 1960s, a paucity of ice‐jam flooding in the lower Peace River has resulted in prolonged dry periods and considerable reduction in the area covered by lakes and ponds that provide habitat for aquatic life in the Peace–Athabasca Delta (PAD) region. Though major ice jams occur at breakup, antecedent conditions play a significant role in their frequency and severity. These conditions are partly defined by the mode of freezeup and the maximum thickness that is attained during the winter, shortly before the onset of spring and development of positive net heat fluxes to the ice cover. Data from hydrometric gauge records and from field surveys are utilized herein to study these conditions. It is shown that freezeup flows are considerably larger at the present time than before regulation, and may be responsible for more frequent formation of porous accumulation covers. Despite a concomitant rise in winter temperatures, solid‐ice thickness has increased since the 1960s. Using a simple ice growth model, specifically developed for the study area, it is shown that porous accumulation covers enhance winter ice growth via accelerated freezing into the porous accumulation. Coupled with a reduction in winter snowfall, this effect can not only negate, but reverse, the effect of warmer winters on ice thickness, thus explaining present conditions. The present model is also shown to be a useful prediction tool, especially for extrapolating incomplete data to the end of the winter. Copyright © 2007 Crown in the right of Canada. Published by John Wiley & Sons, Ltd.

McMurray Formation foraminifera within the lower Albian (Lower Cretaceous) Loon River shales of northern Alberta

Early Cretaceous paleogeography and biostratigraphy of western Canada are reviewed in light of a reassessment of foraminiferal and microfloral data from unpublished university theses on the early Albian Loon River shales of the lower Peace River area of northern Alberta (Norris 1951; Trollope 1951). The Loon River Formation, once considered to be an obsolete term, comprises numerous “zones” of foraminifera, radiolarian, and algal cysts, in ascending order Rectobolivina sp., lower Radiolarian zone, lower Leiosphaeridia zone, Haplophragmoides yukonensis, upper Radiolarian zone, upper Leiosphaeridia zone, Trochammina mcmurrayensis, Valvulineria loetterlei, Haplophragmoides topagorukensis, Marginulinopsis collinsi, and Haplophragmoides gigas minor. The upper part of the Loon River Formation, from the upper Radiolarian zone onwards, correlates with the McMurray, Wabiskaw, and Clearwater formations of the Fort McMurray area of northeastern Alberta. Molluscan data from various localities in western Canada indicates that the entire Loon River succession occurred within the early Albian. The presence of Inoceramus dowlingi and Cleoniceras sp. with the Marginulinopsis collinsi microfauna permits correlation of the type Clearwater Formation and type McMurray Formation with the Moosebar Formation of northeastern Bristish Columbia. An anomalous thick sequence of Leiosphaeridia (algal cysts) beds, bounded above and below by radiolarian-bearing strata, occurs in the mid part of the Loon River shales outcropping ~40 km along the lower Peace River. The Trochammina mcmurrayensis microfauna occurs 2–3 m below Inoceramus dowlingi and 30 m above Cleoniceras sp., and above the upper Leiosphaeridia zone. The radiolarian and Leiosphaeridia beds are considered to be the offshore neritic homotaxial equivalent of deltaic strata in the upper part of the McMurray Formation. The mid and lower Loon River shales are potential oil sources for the tar of the McMurray Formation, and this is supported by recent radiometric dating of the tar by Rhenium–Osmium isotopic analysis.