Heat flow through earth dams : a dam performance monitoring tool

Reservoirs located in temperate climates undergo seasonal temperature fluctuations, warm in the summer and cold in the winter. As a result, the temperature of the water seeping through embankment varies with the season. Heat from the reservoir propagates through dams by two main processes: convection and conduction. The variation in seepage water temperature can be used as a tracer to detect and monitor seepage flow through dams. Temperature measurements from the saturated zone of dams have been collected and qualitative and simplified quantitative methods of data analysis have been used to detect relative changes in the seepage regime. This thesis used two dimensional, uncoupled (fluid and heat flows) numerical models to simulate heat flow through dams and determine seepage velocities. The numerical programs used in this thesis were SEEP/W and a modification of CTRAN/W, produced by GEO SLOPE International Inc. of Calgary. The programs were run in succession, beginning with SEEP/W. The analytical method was first tested by comparing results to a closed form solution simulating one dimensional flow (heat and water) through a homogenous material. Secondly the numerical method was applied to analyse heat flow through a field scale model dam in Germany, followed by an analysis of BC Hydro's Coquitlam Dam. The numerical method was successful in simulating one dimensional flow. The method was also capable of simulating fluid and heat flow through the field scale dam, which had a simple stratigraphy. However, the hydraulic conditions at Coquitlam Dam are more complex and a two dimensional model was not able to account for the flow variations at this dam. A three dimensional model appears necessary to accurately simulate the fluid and heat flow conditions of Coquitlam Dam. Temperature data collected from Coquitlam Dam was qualitatively assessed. No obvious signs of preferential seepage paths were detected. Although the numerical models used in this thesis were shown to effectively model fluid and heat flow, the three step process required to use these modelling programs became cumbersome for more complicated flow conditions. It is recommended that an integrated program be utilized to analyse complex systems, such as Coquitlam Dam.Applied Science, Faculty ofCivil Engineering, Department ofGraduat