UMX was mobilized to Prince William County on two occasions. The first mobilization was to perform an inspection of the dam’s apron to locate and mark areas that may be leaking and to provide a written report outlining methods to isolate the leaks. The second mobilization was to isolate the leaks using various methods. This project was determined to be a substantial risk due to the existing differential pressure, which had to be isolated in order for the project to be performed safely.