HR: 0830h
AN: H11C-0877    [PDF]
TI: Use of GIS and Data Visualization Tools for Modeling Aquifer Architecture and Generating Aquifer Vulnerability Maps at a Regional Scale
AU: * Scibek, J
EM: scibek@sfu.ca
AF: Simon Fraser University, Department of Earth Sciences, 8888 University Drive, Burnaby, BC V5A 1S6 Canada
AU: Allen, D M
EM: dallen@sfu.ca
AF: Simon Fraser University, Department of Earth Sciences, 8888 University Drive, Burnaby, BC V5A 1S6 Canada
AU: Bishop, T W
EM: twbishop@sfu.ca
AF: Simon Fraser University, Department of Earth Sciences, 8888 University Drive, Burnaby, BC V5A 1S6 Canada
AU: Wei, M
EM: mwei@gems5.gov.bc.ca
AF: BC Ministry of Water, Land and Air Protection, 3-2975 Jutland Street, Victoria, BC V8T 5J9 Canada
AB: The Grand Forks aquifer aquifer is one of the first aquifers in the province of British Columbia to undergo a full hydrogeologic characterization because of its importance as a water supply. It is also being used as a case study area for modelling the impact of climate change on groundwater. The aquifer consists of a layered sequence of glacial and alluvial sediments overlying bedrock, which from the top down are comprised of gravel, sand, silt and clay. Aquifer hydrostratigraphy was defined based on some over 300 water well records contained from in the BC Ministry of Water, Land and Air Protection Water WellWELL Database. Lithology data were first standardized to correct errors in syntax, grammar and spelling, recognize equivalent terms, and classify the materials into dominant types so that calculations involving the database could be more easily undertaken. Standardized data have beenwere then used to construct an aquifer architecture model that can be used as input to a numerical groundwater flow model and to construct a vulnerability map. The three-dimensional aquifer architecture model was developed in the data visualization software (GMS) by first constructing cross-sections, and later, generating a solid model that represents the layering and spatial heterogeneity of the aquifer. The bedrock surface was modeled using geostatistical techniques to produce a bedrock digital elevation model (DEM) that better constrains the lower bound of the model. Layers were imported into the numerical groundwater flow code, Visual MODFLOW, and are being used to model current climate conditions and climate change scenarios for the Grand Forks region. A GIS was also used to capture the spatial variability in the input parameters that are used to construct vulnerability maps. Using the DRASTIC approach, indices were assigned to each of seven hydrogeologic parameters. A rastor map was generated for each. A digitized soils map was used to assign soil material and soil topography indices to soil polygons. Indices for depth to water, aquifer media at the water table, aquifer conductivity and impact of vadoze zone were derived from well lithology data, and were interpolated within the GIS to provide a continuous surfaces. Spatial variability in recharge reflects both natural recharge and estimates of return flow from water pumped to irrigate cropsirrigation. The rastor maps for each parameter index were weighted and added togethersummed to produce the DRASTIC vulnerability index map. The use of GIS and data visualization software is invaluable for effectively managing the volume of data and representing spatial variability in regional aquifers.
DE: 1829 Groundwater hydrology
SC: Hydrology [H]
MN: 2003 Fall Meeting