Wolf Creek Dam Seepage Analysis and 3-D Modeling

AMEC was called upon in 2004 and again in 2008, to assist the Nashville District USACE in analyzing historical and current data, and displaying the data to help visualize the existing seepage issues at Wolf Creek Dam in south central Kentucky. The amount of information available from the 1940's era dam includes the original geotechnical investigations, design of the dam and detailed construction documentation, the remedial grouting programs, diaphragm wall construction, instrumentation and observations of the embankment and various supplemental investigations accumulated and archived over the past 60+ years. This has created an intimidating and complex volume of data. To assist our client to better understand the information and how differing sets of data relate to each other, we employed a tool originally developed for mining and environmental engineering applications. The study results were input into the MVS/EVS (Mining Visualization System/Environmental Visualization System) software program which provides 3-dimensional representations of multiple data sets. The original study, published in 2004, has been built upon with the data obtained from other studies and over 1,300 additional borings completed during calendar years 2007 and 2008 by ACT, Gannett Fleming, Willowstick, and others. The modeling programs were obtained from C-Tech Development Corporation (Kahuku, Hawaii). The historical and new data, were converted into the following layers: 1) Surface Topography, 2) Aerial Photography, including Lidar mapping imagery, 3) 3-D structures (grout curtains, diaphragm wall, etc.), 4) Diaphragm Wall, 5) Grout Curtain, 6) Geology, 7) Top of Rock compiled from numerous sources, 8) Temperature survey, 9) Piezometer (water level) Data, 10) Wet Areas, 11) Reservoir level, 12) Willowstick data, 13) Multibeam sonar contours, and 14) Ongoing foundation grouting data. The MVS/EVS software was used to create 3-D surfaces which could be used to show individual layers or combined with any or all layers for analysis. For the first time, the spatial relationship between differing sets of data, such as the top of bedrock, geology and water levels in the embankment, could be viewed at the same time in 3-dimensions. Moreover, the time history data, the fluctuation of lake levels could be compared to water levels in the embankment and to wet areas downstream, and evaluated over a 20 year, or longer, period. In addition, the ability to readily change the prospective of the 3-D model allows the engineer to envision the surface and subsurface information in a new prospective. Past, present and all additional data obtained since the completion of the study can be readily added to the model to compare the previous results or presented as current conditions as compared to present lake elevations and conditions. 22 pp., 26 figures, 8 references.