2026 Webinar: Voids Beneath Spillway Slabs: Evaluation, Interim, and Long-term Risk Reduction Consid

When:  Nov 10, 2026 from 12:00 to 14:00 (ET)
Speakers: Bill Dressel, P.E., Barr Engineering Co., Senior Dam Engineer

PDHs: This webinar is eligible for 2 PDH credits. 

This webinar will introduce lessons learned related to voids beneath spillway slabs. Case histories will be presented highlighting different detection, monitoring, interim and long-term repair techniques. The development and subsequent evaluation of potential failure modes associated with voids beneath spillways will be presented along with a discussion of different interim risk reduction and long-term repair considerations and alternatives. Case histories will include various state and private owner examples.

Key Takeaways:
1. Gain an awareness of Potential Failure Modes (PFMs) associated with voids underneath spillways and learn how to use analysis results to assess these PFMs.
2. Become more familiar with different field exploration approaches and non-destructive techniques for detecting and monitoring voids using case histories to illustrate key principles.
3. Recognize the advantages and limitations of various monitoring methods.
4. Learn about the evaluation of different interim and long-term repair alternatives.
5. Understand the complexity and coordination required when evaluating interim risk reduction measures.
6. Broaden knowledge regarding the theory, application, and design of defensive measures.