The success of oil sands reclamation can be impacted by soil salinity depending on the materials used for soil reconstruction and the capping strategies applied. Using both a greenhouse-based column experiment and numerical modeling, we examined the potential pathways of salt migration from saline groundwater into the rooting zone under different capping strategies (the type and the thickness of the barrier layer) and water balance scenarios. The experimental results showed that there would be salinity issues in the cover soil within several growing seasons if there was a shallow saline groundwater table and if the soil was not properly reconstructed. The thickness of the barrier layer was the most significant factor affecting the upward movement of saline groundwater and salt accumulation in the cover soil. The suitable thickness of the barrier layer for preventing the upward movement of saline groundwater and salt accumulation in the cover soil for each material varied. A numerical simulation for a 15-year period further indicates that, when the cover soil was 50 cm of peat-mineral soil mix and when wet, dry, or normal climatic conditions were considered, the minimum barrier thickness to restrain salt intrusion into the cover soil in the long term was about 75 or 200 cm for coarse tailings sand or overburden barrier material, respectively. In view of the above, to minimize salt migration into the rooting zone and ensure normal plant growth, oil sands reclamation should consider salt migration when designing soil capping strategies.

We developed a scientifically robust monitoring protocol to enable a consistent assessment of ecological recovery of physical, chemical, and biological indicators at certified reclaimed industrial well pads on grasslands.Using the developed protocols, data can be generated from measurement of soil, vegetation, and landscape indicators at reclaimed well pads and adjacent reference sites.We selected the appropriate vegetation, soil, and habitat indicators for a long-term reclamation monitoring program and have provided sampling protocols for the selected indicators here.The protocols may be used to identify and prioritize indicators of reduced ecosystem health and to track ecological recovery of reclaimed sites over time.The development of these integrated monitoring protocols is a first step towards successful and consistent long-term monitoring to assess ecological recovery of certified reclaimed well pads on grasslands.

We developed a scientifically robust and financially sustainable monitoring protocol to enable a consistent assessment of ecological recovery of physical, chemical, and biological indicators at certified reclaimed industrial wellsites in forested lands in noutheastern Alberta. Using the developed protocols, data can be generated from measurement of soil, vegetation, and landscape indicators at reclaimed wellsites and adjacent reference sites. We selected the appropriate vegetation, soil, and habitat indicators for a long-term reclamation monitoring program and have provided sampling protocols for the selected indicators here. The protocols may be used to identify and prioritize indicators of reduced ecosystem health and to track ecological recovery of reclaimed sites over time. The development of these integrated monitoring protocols is a first step towards successful and consistent long-term monitoring to assess ecological recovery of certified wellsites in Alberta. These protocols can be applied to wellsites and other similar sized disturbances in other forested regions too.

Landscape-level disturbance is a reality in many parts of the world including the Athabasca oil sands region, Canada, and soils play an essential part in the overall reclamation process. Soils are reconstructed during reclamation to provide a foundation and a nutrient source for the novel ecosystems. However, reclamation is often monitored through structural indicators of soil quality, which may not reflect dynamic ecosystem functions such as nutrient cycling. Our objective was to determine if nutrient cycling was occurring on novel ecosystems and if standard structural measures of soil quality were appropriate indicators. We assessed soil quality and nitrogen cycling in reclaimed, harvested and undisturbed aspen forest sites following the addition of N-15-labelled aspen ( Populus tremuloides Michx.) leaf litter to the soil surface. Structural soil quality indicators, including soil moisture and microbial carbon and nitrogen biomass, were higher on the undisturbed site, whereas soil microbial composition differed among sites. Yet, uptake of N-15 by microbes and plants, which continued throughout the 52 mo field incubation, was comparable across all sites. These results indicate that differences in structural attributes between disturbed and undisturbed soils do not necessarily translate into differences in soil functioning related to nitrogen cycling. Instead, this case study supports exploring the use of stable isotope tracers to assess dynamic soil function indicators in reclaimed ecosystems. Being able to follow biogeochemical cycling as vegetation becomes established and new forests start to develop following reclamation is key to assessing the long-term sustainability of these novel ecosystems.

Assessing the success of soil reclamation programs can be costly and time-consuming due to the cost of traditional soil analytical techniques. One cost-effective tool that has been successfully used to efficiently analyze a range of soil parameters is reflectance spectroscopy. We used reflectance data to analyze natural and reclaimed soils in the field, examining three key soil parameters: soil organic carbon (SOC), total nitrogen (TN), and soil pH. Continuous wavelet transforms combined with machine learning models were used to predict these parameters. Based on the root mean square error (RMSE), R2 value, and the ratio of performance to deviation (RPD), the Cubist model produced the most accurate models for SOC, TN, and pH. The RMSE, R2, and RPD values for SOC were 0.60%, 0.80, and 2.2, respectively. The TN model results were 0.05%, 0.81 and 2.5, and pH model results were 0.44, 0.69 and 1.8. Overall, the optimal model can be used to predict SOC and TN accurately, and improvements in the pH model are needed as pH values less than 6.5 were consistently overpredicted.

As part of any terrestrial Carbon Capture and Storage (CCS) project, a risk-driven Measurement Monitoring and Verification (MMV) plan may include the measurement of soil gas and related surface CO2 efflux in order to determine the natural (or baseline) concentration range and variation of CO2. Subsequent measurements of these parameters may then act as a measure of stored CO2 containment and conformance during operational, closure and post-closure phases. There are several practical challenges involved in the collection of representative soil-respired CO2 efflux measurements. These include (i) the assessment of natural baseline variations of soil-respired CO2 efflux across potentially large areas expected for commercial CCS operations, (ii) even if field measurements of soil- respired CO2 are recorded over one season or several seasonal cycles, the full concentration and CO2 flux range may not be captured due to reliance upon environmental (i.e. climate) conditions prevalent during field surveys, and (iii) when field based soil CO2 flux measurements are taken, climatic and environmental conditions are likely to change throughout the day, resulting in a number of dislocated flux measurements taken under different conditions. Ideally, it would be useful to be able to carry out an initial field survey measurements, collect soil samples at a project site and develop a simulated baseline in the laboratory under controlled conditions, reducing the seasonal baseline survey duration from one or two years down to several weeks of simulation supported by field verification. Soil cores and bulk material from each soil horizon at selected locations were sampled from the previously proposed Heartland Area Redwater Project (HARP) near Edmonton, Alberta. Soil columns were reconstituted in the laboratory and subjected to a range of temperature and moisture conditions similar to those expected for the CCS project area over a seasonal cycle. Efflux data were directly compared to field-based measurements collected over a 12 month period under a range of climatic conditions. Comparisons between laboratory simulations and field data suggest a strong temperature-efflux correlation consistent with many studies related to the carbon cycle and ecosystem productivity. It is suggested that the simulation of environmental conditions using soils from a CCS area of review may be a useful tool for the prediction of the range of CO2 efflux expected as a function of soil characteristics and environmental conditions, thereby accelerating baseline studies, establishing the range of CO2 efflux to guide monitoring strategies and for the facilitation and validation of remote sensing data in support of large scale CCS site characterization.