Hydrogeological Considerations for Landscape Reconstruction and Wetland Reclamation in the Sub-humid Climate of Northeastern Alberta, Canada
Bibliographic record
Abstract
Oil sands mining companies must reclaim tailings deposits to equivalent land capability in Alberta’s boreal forest. Post-mining landscapes should be reconstructed to promote the development of hydrologic systems that can sustain reclaimed ecosystems in a sub-humid climate, while limiting migration of salts from underlying waste materials. However, landform design requirements that foster the development of appropriate near-surface hydrologic flow systems are poorly understood. Syncrude Canada Ltd. constructed Sandhill Watershed (SHW), a 52 ha coarse-textured upland/lowland complex overlying a deep tailings deposit, to explore the influence of landform characteristics, reclamation cover choices and vegetation densities on reclamation performance. This study examines the hydrogeologic characteristics of SHW and explores the resulting groundwater flow system in the years following its construction. Field measurements collected from May to October (2015 to 2017), from 230 shallow piezometers, including groundwater measurements (water level, temperature, and electrical conductivity), water samples and soil saturation maps were used to characterize the hydrogeology. A subset of data, including stable water isotopes and elemental chemistry, were collected during 2017 to resolve the mechanisms leading to observed solute distributions. Field observations were used to calibrate a three-dimensional steady-state numerical groundwater flow model to evaluate present and possible future hydrologic systems. A shallow groundwater system dominated by lateral flow developed within SHW. The flow system is strongly influenced by hydraulic conductivity and appears to have negligible inputs from deeper groundwater. Most recharge originates from a laterally extensive upland feature coinciding with the adjacent groundwater divide, beyond the southern extent of the study area. Shallow water tables near, and standing water in, the lowlands are most sensitive to precipitation. Overall, solute concentrations increase with depth in the watershed; however, areas with shallow water tables and shallow slopes are prone to developing elevated solute concentrations following precipitation events. Analyses indicate water table configurations responded dynamically to variable recharge rates associated with the depth to water table, and reclamation prescriptions for soil and vegetation. These results indicate fresh shallow groundwater systems can develop for wetland reclamation in post-mining reconstructed landscapes. By appropriately sculpting coarse-textured construction materials during landform design, a freshwater lens developed at the water table beneath hummocks where groundwater is approximately 2 m below ground surface; here, the vertical geochemical gradient transitions from mixed-fresh groundwater to Na+ Cl-/SO4 2- enriched groundwater approximately 1.8 m below water level. Sloped areas with shallower water tables that fluctuate within the rooting zone tend to have elevated solute concentrations near the water table, especially following precipitation influxes, due to lateral groundwater seepage, groundwater ridging and evapoconcentration. These results provide guidance for designing future coarse-textured landforms and developing hydrologic systems for boreal forest reclamation. In particular, designers should reconstruct watersheds that promote groundwater recharge in upland areas by building lower and more laterally expansive hummocks than those in SHW to support water tables approximately 2 m BGS. Furthermore, the interface between the uplands and lowlands should be abrupt, to limit the extent of seepage faces. With these slight landform modifications, recharge and solutes can be better managed to allow the shallow groundwater system to remain fresh, while sustainably sourcing water to down gradient environments.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.002 |
| Science and technology studies | 0.002 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".