Understanding the hydrological controls on subsurface flow and transport is of considerable importance in the study of reclaimed landscapes in the oil sands region of Canada. A significant portion of the reclaimed landscape will be comprised of a thin veneer (~ 1 m) of clay-rich reclamation soil overlying saline-sodic shale overburden, which is a waste by-product from the mining process. The global objective of this study was to investigate the first-order controls on soil moisture and salt transport dynamics within clay-rich reclamation covers overlying low permeability waste substrates. The study site is located in a cold, semi-arid climate in the oil sands region of northern Alberta. Preferential flow was the dominant mechanism responsible for the development of perched water table conditions on the cover-waste interface during the spring snow melt. Hydrological and geochemical data indicated that snowmelt infiltration occurs via the macroporosity while the ground is still frozen. An isotope hydrograph separation conducted on water collected in a weeping tile confirmed the presence of fresh snowmelt water at the onset of subsurface flow. This water transitions to a chemical signature that is comprised of approximately 80% connate pore water as a result of chemical equilibration between pore water in the soil matrix and fresh water in the macropores.<p>Detailed mapping of the spatial distribution of soil moisture and salts within a reclamation cover indicated the lower-slope positions are wetter due to the accumulation surface run-off and frozen ground infiltration in spring. Increased soil moisture conditions in lower-slope positions accelerate salt ingress, while drier conditions in middle and upper-slope positions attenuate salt ingress. The data indicated that fresh snowmelt water is bypassing the soil matrix higher in the cover profile. Subsurface flow and deep percolation are key mechanisms mitigating vertical salt ingress in lower and upper slope positions. The mesotopography of the cover-waste interface imposes a direct control on the depth of perched water and the downslope routing of water. Undulations in the cover-waste interface cause the depth of perched water to vary considerably (± 20 60 cm) over short distances (< 5 m), while saturated subsurface flow is routed through the lowest elevations in the cover profile. A numerical analysis of subsurface flow was able to simulate both the discharge rate and cumulative volume of flow to a weeping tile. Composite hydraulic functions were used in the simulations to account for the increased hydraulic conductivity and drainable porosity created by the macroporosity at near-saturated conditions. The transient Na+ concentration of discharge water was modelled using the concept of an equivalent porous medium. The good match between measured and modelled data verified the conceptual model, which contends that saturated subsurface flow is dominated by the fracture network and that the concentration of discharge water is function of the depth of perched water. Finally, the results from this study suggest the mesotopography of the cover-waste interface could be used to manage excess water and salts within the landscape.

Surface mining often changes the native landscape and vegetation of an area. Reclamation is used to counter this change, with the goal of restoring the land to its original pre-mined state. The process of reclamation creates early successional-stage lands, such as grasslands, shrublands, and wetlands, attracting new plant and animal species to the area. I compared avian species density (number of individuals/ha), diversity (H'), and richness (number of species/ha) on reclaimed and non-mined lands at TXU's Big Brown Mine in Fairfield, Texas. I also compared my results to those of a previous study conducted 25 years earlier. Avian counts were conducted using a fixedradius point-count method on 240 points placed in four different vegetation types and in four land-age groups (time since being reclaimed). Vegetation was measured both locally, and at a landscape level. Overall bird species density did not exhibit a clear relationship on non-mined versus reclaimed land. Overall bird species diversity was greater on non-mined lands, whereas overall species richness was greater on reclaimed lands. My results demonstrated a lower mean/point bird density and higher mean/point bird diversity than were found 25 years earlier. Different nesting guilds occurred on the reclaimed lands than occurred on the non-mined lands. Results suggested different species were attracted to the several successional stages of reclaimed lands over the nonmined lands, which consisted of climax vegetation. The different successional stages of reclaimed lands increased overall diversity and richness of the landscape as a whole. Five bird species of conservation concern were observed in the study, all of which occurred on reclaimed land. Four of the five species primarily occurred on reclaimed lands. Future land management should include conserving different successional-stage lands to increase overall biotic diversity and richness of mined land, preserving reclaimed habitat for species of concern, and educating future private landowners on the importance of maintaining vegetative and bird species diversity.

Thesis (M.S.)--West Virginia University, 2002. / Title from document title page. Document formatted into pages; contains ix, 114 p. : ill. (some col.), map. Includes abstract. Includes bibliographical references (p. 92-107).

Thesis (M.A.)--West Virginia University, 2003. / Title from document title page. Document formatted into pages; contains vii, 56 p. : ill. (some col.), maps (some col.). Vita. Includes abstract. Includes bibliographical references (p. 50-55).

Graduate

Reclamation of four salt-affected soils collected from southern Arizona was studied in the greenhouse and laboratory. Two rates of four amendments (sulphuric acid, gypsum, ammonium polysulphide, and ammonium thiosulphate) were applied in triplicate. Results were evaluated in terms of changes in nutrient availability, ions removed by leaching, plant growth, and infiltration rates. In most cases the high rates of sulphuric acid and gypsum increased the solubility of the major cations (Na, K, Ca, and Mg) in the soil. If the required amount of leaching water were applied to the soil, a significant amount of these cations, especially Na, was leached from the soil. For the Gothard soil (saline-sodic) two pore volumes were sufficient to accomplish leaching, but were insuffcient for the Guest (nonsaline-slightly sodic) and Gilman (highly saline-sodic) soils. High rates of sulphuric acid and gypsum decreased the pH and increased the EC for all soils, although the EC was not significant at the 5% level for the Mohall (nonsaline-nonsodic, calcareous) soil. All treatments decreased the pH of the Gothard soil significantly; however, the greatest increase in EC and least pH were obtained from acid application. Regarding changes in phosphorus (P), all treatments increased the amount of soluble P in the leachates from the Gothard and Guest soils; whereas available soil P increased significantly only with the acid treatments. None of the treatments affected the amount of P in the Gilman soil leachates, but acid and gypsum increased the available soil P. Ammonium polysulphide and ammonium thiosulphate tended to increase available P but the increase was not significant at the 5% level. None of the treatments affected the P parameters for the Mohall soil. Sulphuric acid increased growth and P uptake of alfalfa plants on all soils except the Mohall. Gypsum and ammonium polysulphide increased P uptake on the Gothard and Guest soils whereas ammonium thiosulphate increased P uptake only for the Guest soil. Sulphuric acid and gypsum increased the infiltration rates for all four soils. Thiosulphate produced intermediate infiltration rates while the lowest rates were found with ammonium polysulphide and the untreated soils. Although amendment rates were based on equivalent amounts of sulphur and their effectiveness in supplying soluble calcium, and the exchangeable sodium status of each soil, results varied according to such factors as rate of oxidation of the amendment, lime content of the soil, soluble salts present in the soil, and soil texture.

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