Irrigation rates in excess of plant evapotranspiration requirements have been identified as a major contributor to the development of raised water tables in the City of Lethbridge. These high water tables have created problems such as coulee slope instability, basement flooding and structural instability. This study characterized water table conditions in Lakeview subdivision, an area that experiences basement flooding. Soil texture data from this subdivision is used to address speculation that geologic controls contribute to high water tables in the city of Lethbridge, Linear regression analysis comparing mean sand and clay fractions to mean water table depth revealed that variations in soil texture have no statistical relationship to variations in water table depth. Glacio-lacustrine sediments underlie Lakeview subdivision while tills predominate in the Varsity Village area. Lakeview subdivision is also approximately 20 years older than Varsity Village and the two are compared to gain some understanding of how water tables develop over time. Comparison of mean water table depths in irrigated and non-irrigated land cover classes in both Varsity Village and Lakeview revealed a significant difference in Varsity Village whilc Lakeview showed no statistical difference. Finally, a water scheduling program is developed to decrease or reduce the build-up of water tables and alleviate some of the problems that result. / x, 169 leaves : ill. ; 29 cm

In subhumid to arid climates throughout the world, recharge to groundwater in urban areas is often found to be higher than pre-urbanization rates, despite an increased percentage of impermeable surfaces. Groundwater recharge in the city of Lethbridge is substantially higher than recharge rates prior to urbanization, resulting in the formation of perched water table conditions. High perched water table conditions, typically at depths between one and 2.5 metres, have created problems for the City and University of Lethbridge, including the increased occurrence of slope failures along nearby coulees. This study estimates of the volume of excess water available for groundwater recharge through the practices of urban turfgrass irrigation, and water storage. Between May and September, 1990-1996 irrigation was applied far above evapotranspiration demands, resulting in large volumes of water available for groundwater recharge in the Varsity Village subdivision of the City of Lethbridge. The relationship between the amount of water applied and the development of perched water table systems was strong enough that equations between inputs and water table depth could be derived, and used to predict water table elevation. / xiii, 190 leaves : ill., maps ; 28 cm.