Improving dam safety by addressing stability, seepage, and overtopping for maximum flood pools

Douglas Saddle Dams and Dandridge Dike

To safeguard downstream communities during maximum flood pool conditions, Tennessee Valley Authority (TVA) called on our team as a trusted partner to assess 10 saddle dams and a dike embankment at the Douglas Dam project.

Our initial work included a field exploration, laboratory testing program, and an updated stability evaluation of all 10 saddle dams as well as the Dandridge Dike embankment. Based on the stability analyses, we were tasked with an operability assessment of Saddle Dam Number 1. When the dam did not meet current design criteria, we were entrusted with the design of relief wells and a rockfill berm to improve safety factors against soil heave at the dam toe. At Saddle Dams Number 3 and 9, we designed similar modifications to improve safety and stability. To prevent overtopping at the maximum pool, our team designed modifications to raise the crest of Saddle Dams Number 2, 3, and 10.

Altogether, we performed global stability evaluations, operability assessments, and design modifications while meeting aggressive schedules—expedited and completed prior to the spring flooding season. Assisting TVA during construction also helped verify the modifications were built in accordance with the design.