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Development of a GIS Water Table Visualization Tool (WTVT) for Determining Water Table Position in Heterogeneous Landscapes in the Boreal Plains Ecozone, Alberta
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- Author / Creator
- Nelson, Aurnir Bartley
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The Boreal Plain is currently undergoing an unprecedented rate of land use change from oil and gas extraction as well as forestry. This change needs to be managed responsibly to ensure the long term sustainability of the region, both ecologically and economically. As part of this understanding the location of the water table in forested uplands is critical in predicting the potential effects of disturbance on the sustainability of water resources. Typically the water table is located using topographically based models. These models, however, were developed in regions of Canada that have very different precipitation regimes and do not experience the depth and heterogeneity of soils characteristic of the Boreal Plain, Alberta. In this research, existing eco-hydrologic information for the sub-humid Boreal Plain, Alberta has been applied to the construction of a Water Table Visualization Tool (WTVT) at the Al-Pac Catchment Experiment near Lac La Biche, Alberta. Unlike topographically based models, the WTVT incorporates landform texture, surface wetland location, and surface elevation to create a visualization of the water table. This novel application of GIS methodology involves three algorithms of water table form: one each for coarse, fine, and coarse-over-fine (COF) textured hydrologic response areas (HRAs). In addition to assessing water table elevation estimates from the WTVT, this research also examined a surficial geology texture interpretation process, and compared two different resolution wetland classifications as input for surface water location. Analysis of landform texture, which was interpreted from existing surficial geology landform mapping, indicates that the proposed interpretation process should further consider the specific localized landform development and that broad scale generalizations may be misleading. Topographic analysis of landform shape indicates that use of the two different resolution wetland classifications in the WTVT resulted in different quantities and spatial configurations of zero depth water. The higher resolution wetland classification resulted in greater total wetland area and wetlands occupying more of the concave topography within the study area. Root mean square error algorithm comparisons within individual HRAs indicated that within the coarse-textured HRA the fine algorithm performed best, within the fine-textured HRA results were unclear, and within the coarse-over-fine (COF) textured HRA the COF algorithm performed best. Manual calibration of the algorithms showed only the COF HRA had acceptable reliability with the RMSEs < RMSEu using a subset of wetland input data at both wetland classification resolutions. The validation of the COF textured HRA was within acceptability criteria. Results from both the algorithm comparisons and the calibration-validation procedure emphasized the need to deal with concave landforms discretely within the algorithms. Additionally, a water table sample design should be stratified for a larger sample distribution over a wider range of landforms. The WTVT is able to predict the location of the water table, but further investigation of conceptual models and algorithm refinement may be warranted.
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- Graduation date
- Fall 2015
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- Type of Item
- Thesis
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- Degree
- Master of Science
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- License
- This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.