The Slave River delta is a highly productive and biologically diverse ecosystem located on the so... more The Slave River delta is a highly productive and biologically diverse ecosystem located on the south shore of Great Slave Lake in the Northwest Territories, Canada. There is concern regarding water quality in the Slave River delta due to the transfer of sediment-associated contaminants from upstream sources and long-range atmospheric transport. Previous studies report elevated metal levels in suspended sediment collected in the Slave River at Fort Smith and sediment deposited in the Slave River delta, which either meet or exceed Canadian sediment quality guidelines. However, little is known about the bioavailability and toxicity of sediment-associated metals to aquatic life in the delta. The present study examines the bioavailability of sediment-associated metals and their distribution across the delta. Surface sediment samples were collected in the outer, mid and apex sections of the delta and analysed for total metals, grain size and organic carbon content. Four-week bioaccumulati...
Climate change-associated wildfires are increasing in frequency and severity, causing increasingl... more Climate change-associated wildfires are increasing in frequency and severity, causing increasingly variable or deteriorated water quality, and challenging in-plant treatment processes beyond design and operational response capacities, to the point of service disruptions. Recent work has shown that the wildfire impacts on drinking water treatability can extend far downstream and be long-lasting. Notably, very little information regarding the impacts of severe wildfire on groundwater supplies is currently available.Wildfire transforms fuels (i.e. biomass, soil organic matter). Pyrogenic carbonaceous material formed after wildfire includes particulate ash and biochar, which often contains toxic polyaromatic hydrocarbons, dioxins and furans, as well as some heavy metals. These mobile materials may be incorporated into soil profiles (change the soil properties, e.g., hydrophobicity, pH), redistributed, or removed from a burned site by wind and water erosion to source water. While surface...
The objective of this study was to examine initial effects of the 2003 Lost Creek wildfire (south... more The objective of this study was to examine initial effects of the 2003 Lost Creek wildfire (southwestern Rocky Mountains of Alberta) on concentrations and production (yield and total export) of several nitrogen (N) forms, and to explore initial recovery of these effects within the first 3 years after the fire. During the first postfire year, nitrate (NO3–), dissolved organic nitrogen (DON), and total nitrogen (TN) concentrations in severely burned watershed streams were 6.5, 4.1, and 5.3 times greater, respectively, than those in reference streams. Weaker effects were evident for concentrations of ammonium (NH4+; 1.5 times) and total particulate nitrogen (TPN; 3.0 times). A rapid decline in mean watershed concentrations and production of NO3–, DON, total dissolved nitrogen (TDN), and TN was observed from burned watersheds over the three seasons after the fire. However, elevated NO3–, TDN, and TN concentrations and production were still evident during the snowmelt freshet and followi...
Introduction: In forested watersheds, large scale landscape disturbance by wildfire alter physica... more Introduction: In forested watersheds, large scale landscape disturbance by wildfire alter physical and biogeochemical processes that influence water quality and quantity in streams [1]. Such changes can strongly influence the ecology of downstream reaches [2]. Here we report long term changes in sediment and phosphorus (P) production and their impact on algae in streams studied for 10 years after severe wildfire in the Rocky Mountains (Alberta, Canada).
The Southern Rockies Watershed Project was initiated in 2003 to describe the impacts of severe na... more The Southern Rockies Watershed Project was initiated in 2003 to describe the impacts of severe natural disturbance by wildfire on a broad range of headwaters, larger river basin scale, and downstream water resources (Phase I). This watershed research is unique in that trans-disciplinary linkages between hydrology, biogeochemistry, aquatic ecology, downstream river basin processes, implications for human water use, and economic implications are providing broad insights into wildfire effects on water. A second phase of the research (Phase II) focuses on evaluating the effects of several alternative forest harvesting practices on these same water resource “values”. Collectively, this research is providing comprehensive information on watershed function after forest disturbance in Rocky Mountain watersheds.
The erosion characteristics and bed stability of wildfire-affected stream sediment were measured ... more The erosion characteristics and bed stability of wildfire-affected stream sediment were measured in an annular flume. Biofilms were grown in the flume on cohesive streambed sediments collected from a wildfire affected stream and a reference undisturbed stream in southern Alberta, Canada. Examined factors that influence sediment erosion, settling and bed stability included applied shear stress, geochemical and physical properties of the sediment, floc structural characteristics and consolidation period (2, 7, 14 days). Erosion characteristics and sediment properties were strongly influenced by wildfire, consolidation period and bed biostabilization. The fire-modified sediment was more resistant to erosion than the reference unburned sediment. Settling velocities were lower in the burned sediment due to higher organic content and porosity. The critical shear stresses for erosion were 1.6 and 1.8 times higher for the burn-associated sediment after 7 and 14 days of consolidation. The di...
Forests are critical water supply regions that are increasingly threatened by natural and anthrop... more Forests are critical water supply regions that are increasingly threatened by natural and anthropogenic disturbance. Evaluation of runoff-generating processes within harvested and undisturbed headwater catchments provides insight into disturbance impacts on water quality and drinking water treatability. In this study, an extensive hydrologic dataset collected at the experimental Turkey Lakes Watershed (TLW) located on the Canadian Shield was used to quantify sources of stormflow in legacy clear-cut (24-years post harvesting) and forested (control) headwater catchments using an end member mixing analysis (EMMA) model. Stream water, groundwater, soil water, and throughfall water quality were evaluated during spring snowmelt, stormflow, and fall wet-up. Groundwater chemistry was similar to stream water chemistry in both catchments, suggesting that groundwater is a major contributor to stream flow. The water chemistry in small wetlands within the study catchments was comparable to strea...
Canada. Seven watersheds, with varying degrees of natural and man-made land disturbance (burned, ... more Canada. Seven watersheds, with varying degrees of natural and man-made land disturbance (burned, post-fire salvage logged, unburned) were monitored for three years to assess sediment concentrations and production (export and yield) over a range of flow regimes (spring melt, baseflow and stormflow). Suspended sediment concentrations were 6-times higher in burned watersheds and 11-times higher in post-fire salvage logged watersheds than in unburned watersheds. Sediment availability was greater in both burned and post-fire salvage logged watersheds but varied with flow condition; particularly during the snowmelt freshet and stormflow. In burned watersheds, sediment yield was 5-times higher during snowmelt and 13-times higher during stormflow than in unburned watersheds. Post-fire salvage logging produced much greater impacts than wildfire alone, with mean sediment yield 19-times higher during snowmelt and 9-times higher during stormflow compared to unburned watersheds.
Vegetated roof technologies are used as treatment measures to mitigate the effects of urban storm... more Vegetated roof technologies are used as treatment measures to mitigate the effects of urban stormwater. A mass balance approach was used to assess the treatment performance of a vegetated roof located on the City Hall in Waterloo, Ontario. The vegetated and control roof sections were instrumented to measure precipitation, storage, and outfl ow for 18 storm events from June to October, 2006. Concentrations of suspended solids, total phosphorus (TP), and SRP (SRP) in precipitation and roof (vegetated and control) runoff were measured. A total of 155.6 mm of rain fell during the study period. The vegetated roof retained 64.5 mm (43.9%) of the total rainfall while the control roof retained approximately 5.1 mm (4.0%). For individual rain events, the vegetated roof retained an average of 3.5 mm (47.6%), while the control roof retained approximately 0.3 mm (4.7%). Water retention varied with storm size, season, and frequency of storm events. The vegetated roof retained 80.1 % of precipita...
Nature-based Solutions (NBS) are increasingly proposed for effectively and adaptively addressing ... more Nature-based Solutions (NBS) are increasingly proposed for effectively and adaptively addressing societal challenges such as water security and natural disasters. However, NBS that are exclusively reliant on natural processes are not fit-for-purpose for the provision of safe drinking water—some range of built technology is required. There is a wide spectrum of techno-ecological NBS—“green technologies”—that are fit-for-purpose in the treatment and distribution of safe drinking water. A framework was developed to enable accurate and transparent description of the “green” attributes of technology—including green infrastructure—in the water industry. The framework differentiates technology “greenness” by relatively examining key attributes that may cause environmental impacts across the technology’s life cycle, through the lens of the environmental setting in which it is applied. In the water industry, green technology can be described by four main attributes: natural resource-basis, e...
A collection of papers given at the ICCE Symposium 2016 – Integrating monitoring and modelling fo... more A collection of papers given at the ICCE Symposium 2016 – Integrating monitoring and modelling for sediment dynamics, Okehampton, UK, 11–15 July 2016
The impacts of large-scale land disturbance by wildfire on a wide range of water and related ecol... more The impacts of large-scale land disturbance by wildfire on a wide range of water and related ecological services are increasingly being recognized worldwide. This study explores the long-term impact (6–7 years) of the 2003 Lost Creek wildfire on particulate phosphorus forms (NAIP, AP, OP) of suspended river sediment at a large regional scale (554 km) in the Crowsnest River basin, Alberta, Canada. While total P concentrations were similar among burned and unburned river sediments, the mean bioavailable NAIP fraction remained approximately 70% greater and the organic P over 2-fold higher in sediments from five burned tributary watersheds compared to the reference site in the Crowsnest River study catchment. Because of the key role of phosphorus in regulating aquatic productivity in oligotrophic mountain rivers, these findings highlight the risk of a large scale and long-term legacy of wildfire in some mountain river systems.
Northern Canadian Rivers provide a broad range of ecosystem services, but increasing pressures fr... more Northern Canadian Rivers provide a broad range of ecosystem services, but increasing pressures from development and resource extraction have negatively impacted the ecology and water quality of many of these relatively pristine river systems. The North Saskatchewan River (NSR) drains an area of 57 000 km in northern Alberta and provides water for multiple uses. However, landscape disturbance has increased the flux of a variety of sediments and associated contaminants in this river. To evaluate the spatial (gradient from headwater to downstream sites) and temporal (inter-annual) variation of PAHs in the NSR, grab samples of fine-grained river bed/bank sediment deposits were collected in 2010 and 2011 at 20 monitoring sites over a distance of 1000 km from Rocky Mountain House to Lloydminster. An additional 10 samples were collected in 2011 at the confluence of the main river with tributaries of varying land use. Individual congeners of 16 PAHs were extracted from sediment samples and ...
A mass balance approach was used to quantify concentrations and loads of suspended solids and pho... more A mass balance approach was used to quantify concentrations and loads of suspended solids and phosphorus (P) at the inflow and outflow of Laurel Pond, a small river impoundment in an urbanized watershed in Waterloo, Ontario, Canada, over a range of hydrological conditions. During baseflow and higher magnitude flow conditions, Laurel Pond was a sink for both sediment and P. However, 8.4 t of sediment and 8.6 kg of P were released from Laurel Pond during drawdown. Concentrations of sediment and P were positively correlated but inversely related to pond depth. A threshold water level was observed in the pond, below which the majority of sediment and P were released. During the Laurel Pond drawdown, 94% of suspended solids and 100% of TP measurements at the pond outflow exceeded Ontario Provincial Water Quality Objectives of 25 mg L and 30 μg L, respectively.
The Slave River delta is a highly productive and biologically diverse ecosystem located on the so... more The Slave River delta is a highly productive and biologically diverse ecosystem located on the south shore of Great Slave Lake in the Northwest Territories, Canada. There is concern regarding water quality in the Slave River delta due to the transfer of sediment-associated contaminants from upstream sources and long-range atmospheric transport. Previous studies report elevated metal levels in suspended sediment collected in the Slave River at Fort Smith and sediment deposited in the Slave River delta, which either meet or exceed Canadian sediment quality guidelines. However, little is known about the bioavailability and toxicity of sediment-associated metals to aquatic life in the delta. The present study examines the bioavailability of sediment-associated metals and their distribution across the delta. Surface sediment samples were collected in the outer, mid and apex sections of the delta and analysed for total metals, grain size and organic carbon content. Four-week bioaccumulati...
Climate change-associated wildfires are increasing in frequency and severity, causing increasingl... more Climate change-associated wildfires are increasing in frequency and severity, causing increasingly variable or deteriorated water quality, and challenging in-plant treatment processes beyond design and operational response capacities, to the point of service disruptions. Recent work has shown that the wildfire impacts on drinking water treatability can extend far downstream and be long-lasting. Notably, very little information regarding the impacts of severe wildfire on groundwater supplies is currently available.Wildfire transforms fuels (i.e. biomass, soil organic matter). Pyrogenic carbonaceous material formed after wildfire includes particulate ash and biochar, which often contains toxic polyaromatic hydrocarbons, dioxins and furans, as well as some heavy metals. These mobile materials may be incorporated into soil profiles (change the soil properties, e.g., hydrophobicity, pH), redistributed, or removed from a burned site by wind and water erosion to source water. While surface...
The objective of this study was to examine initial effects of the 2003 Lost Creek wildfire (south... more The objective of this study was to examine initial effects of the 2003 Lost Creek wildfire (southwestern Rocky Mountains of Alberta) on concentrations and production (yield and total export) of several nitrogen (N) forms, and to explore initial recovery of these effects within the first 3 years after the fire. During the first postfire year, nitrate (NO3–), dissolved organic nitrogen (DON), and total nitrogen (TN) concentrations in severely burned watershed streams were 6.5, 4.1, and 5.3 times greater, respectively, than those in reference streams. Weaker effects were evident for concentrations of ammonium (NH4+; 1.5 times) and total particulate nitrogen (TPN; 3.0 times). A rapid decline in mean watershed concentrations and production of NO3–, DON, total dissolved nitrogen (TDN), and TN was observed from burned watersheds over the three seasons after the fire. However, elevated NO3–, TDN, and TN concentrations and production were still evident during the snowmelt freshet and followi...
Introduction: In forested watersheds, large scale landscape disturbance by wildfire alter physica... more Introduction: In forested watersheds, large scale landscape disturbance by wildfire alter physical and biogeochemical processes that influence water quality and quantity in streams [1]. Such changes can strongly influence the ecology of downstream reaches [2]. Here we report long term changes in sediment and phosphorus (P) production and their impact on algae in streams studied for 10 years after severe wildfire in the Rocky Mountains (Alberta, Canada).
The Southern Rockies Watershed Project was initiated in 2003 to describe the impacts of severe na... more The Southern Rockies Watershed Project was initiated in 2003 to describe the impacts of severe natural disturbance by wildfire on a broad range of headwaters, larger river basin scale, and downstream water resources (Phase I). This watershed research is unique in that trans-disciplinary linkages between hydrology, biogeochemistry, aquatic ecology, downstream river basin processes, implications for human water use, and economic implications are providing broad insights into wildfire effects on water. A second phase of the research (Phase II) focuses on evaluating the effects of several alternative forest harvesting practices on these same water resource “values”. Collectively, this research is providing comprehensive information on watershed function after forest disturbance in Rocky Mountain watersheds.
The erosion characteristics and bed stability of wildfire-affected stream sediment were measured ... more The erosion characteristics and bed stability of wildfire-affected stream sediment were measured in an annular flume. Biofilms were grown in the flume on cohesive streambed sediments collected from a wildfire affected stream and a reference undisturbed stream in southern Alberta, Canada. Examined factors that influence sediment erosion, settling and bed stability included applied shear stress, geochemical and physical properties of the sediment, floc structural characteristics and consolidation period (2, 7, 14 days). Erosion characteristics and sediment properties were strongly influenced by wildfire, consolidation period and bed biostabilization. The fire-modified sediment was more resistant to erosion than the reference unburned sediment. Settling velocities were lower in the burned sediment due to higher organic content and porosity. The critical shear stresses for erosion were 1.6 and 1.8 times higher for the burn-associated sediment after 7 and 14 days of consolidation. The di...
Forests are critical water supply regions that are increasingly threatened by natural and anthrop... more Forests are critical water supply regions that are increasingly threatened by natural and anthropogenic disturbance. Evaluation of runoff-generating processes within harvested and undisturbed headwater catchments provides insight into disturbance impacts on water quality and drinking water treatability. In this study, an extensive hydrologic dataset collected at the experimental Turkey Lakes Watershed (TLW) located on the Canadian Shield was used to quantify sources of stormflow in legacy clear-cut (24-years post harvesting) and forested (control) headwater catchments using an end member mixing analysis (EMMA) model. Stream water, groundwater, soil water, and throughfall water quality were evaluated during spring snowmelt, stormflow, and fall wet-up. Groundwater chemistry was similar to stream water chemistry in both catchments, suggesting that groundwater is a major contributor to stream flow. The water chemistry in small wetlands within the study catchments was comparable to strea...
Canada. Seven watersheds, with varying degrees of natural and man-made land disturbance (burned, ... more Canada. Seven watersheds, with varying degrees of natural and man-made land disturbance (burned, post-fire salvage logged, unburned) were monitored for three years to assess sediment concentrations and production (export and yield) over a range of flow regimes (spring melt, baseflow and stormflow). Suspended sediment concentrations were 6-times higher in burned watersheds and 11-times higher in post-fire salvage logged watersheds than in unburned watersheds. Sediment availability was greater in both burned and post-fire salvage logged watersheds but varied with flow condition; particularly during the snowmelt freshet and stormflow. In burned watersheds, sediment yield was 5-times higher during snowmelt and 13-times higher during stormflow than in unburned watersheds. Post-fire salvage logging produced much greater impacts than wildfire alone, with mean sediment yield 19-times higher during snowmelt and 9-times higher during stormflow compared to unburned watersheds.
Vegetated roof technologies are used as treatment measures to mitigate the effects of urban storm... more Vegetated roof technologies are used as treatment measures to mitigate the effects of urban stormwater. A mass balance approach was used to assess the treatment performance of a vegetated roof located on the City Hall in Waterloo, Ontario. The vegetated and control roof sections were instrumented to measure precipitation, storage, and outfl ow for 18 storm events from June to October, 2006. Concentrations of suspended solids, total phosphorus (TP), and SRP (SRP) in precipitation and roof (vegetated and control) runoff were measured. A total of 155.6 mm of rain fell during the study period. The vegetated roof retained 64.5 mm (43.9%) of the total rainfall while the control roof retained approximately 5.1 mm (4.0%). For individual rain events, the vegetated roof retained an average of 3.5 mm (47.6%), while the control roof retained approximately 0.3 mm (4.7%). Water retention varied with storm size, season, and frequency of storm events. The vegetated roof retained 80.1 % of precipita...
Nature-based Solutions (NBS) are increasingly proposed for effectively and adaptively addressing ... more Nature-based Solutions (NBS) are increasingly proposed for effectively and adaptively addressing societal challenges such as water security and natural disasters. However, NBS that are exclusively reliant on natural processes are not fit-for-purpose for the provision of safe drinking water—some range of built technology is required. There is a wide spectrum of techno-ecological NBS—“green technologies”—that are fit-for-purpose in the treatment and distribution of safe drinking water. A framework was developed to enable accurate and transparent description of the “green” attributes of technology—including green infrastructure—in the water industry. The framework differentiates technology “greenness” by relatively examining key attributes that may cause environmental impacts across the technology’s life cycle, through the lens of the environmental setting in which it is applied. In the water industry, green technology can be described by four main attributes: natural resource-basis, e...
A collection of papers given at the ICCE Symposium 2016 – Integrating monitoring and modelling fo... more A collection of papers given at the ICCE Symposium 2016 – Integrating monitoring and modelling for sediment dynamics, Okehampton, UK, 11–15 July 2016
The impacts of large-scale land disturbance by wildfire on a wide range of water and related ecol... more The impacts of large-scale land disturbance by wildfire on a wide range of water and related ecological services are increasingly being recognized worldwide. This study explores the long-term impact (6–7 years) of the 2003 Lost Creek wildfire on particulate phosphorus forms (NAIP, AP, OP) of suspended river sediment at a large regional scale (554 km) in the Crowsnest River basin, Alberta, Canada. While total P concentrations were similar among burned and unburned river sediments, the mean bioavailable NAIP fraction remained approximately 70% greater and the organic P over 2-fold higher in sediments from five burned tributary watersheds compared to the reference site in the Crowsnest River study catchment. Because of the key role of phosphorus in regulating aquatic productivity in oligotrophic mountain rivers, these findings highlight the risk of a large scale and long-term legacy of wildfire in some mountain river systems.
Northern Canadian Rivers provide a broad range of ecosystem services, but increasing pressures fr... more Northern Canadian Rivers provide a broad range of ecosystem services, but increasing pressures from development and resource extraction have negatively impacted the ecology and water quality of many of these relatively pristine river systems. The North Saskatchewan River (NSR) drains an area of 57 000 km in northern Alberta and provides water for multiple uses. However, landscape disturbance has increased the flux of a variety of sediments and associated contaminants in this river. To evaluate the spatial (gradient from headwater to downstream sites) and temporal (inter-annual) variation of PAHs in the NSR, grab samples of fine-grained river bed/bank sediment deposits were collected in 2010 and 2011 at 20 monitoring sites over a distance of 1000 km from Rocky Mountain House to Lloydminster. An additional 10 samples were collected in 2011 at the confluence of the main river with tributaries of varying land use. Individual congeners of 16 PAHs were extracted from sediment samples and ...
A mass balance approach was used to quantify concentrations and loads of suspended solids and pho... more A mass balance approach was used to quantify concentrations and loads of suspended solids and phosphorus (P) at the inflow and outflow of Laurel Pond, a small river impoundment in an urbanized watershed in Waterloo, Ontario, Canada, over a range of hydrological conditions. During baseflow and higher magnitude flow conditions, Laurel Pond was a sink for both sediment and P. However, 8.4 t of sediment and 8.6 kg of P were released from Laurel Pond during drawdown. Concentrations of sediment and P were positively correlated but inversely related to pond depth. A threshold water level was observed in the pond, below which the majority of sediment and P were released. During the Laurel Pond drawdown, 94% of suspended solids and 100% of TP measurements at the pond outflow exceeded Ontario Provincial Water Quality Objectives of 25 mg L and 30 μg L, respectively.
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Papers by Micheal Stone