Precision Matters: Surveying Fundamentals for Dam Safety: Agenda

January 13, 2026
12:00 PM - 2:00 PM Eastern

Different Surveys and the accuracy to expect from each
- Conventional Ground (Topo)
- Aerial Photography (Drone vs. Airplane)
- Bathymetric survey - share technology and how it's changed, videos
Owner - basics of what they should expect from a surveyor
Continuous monitoring - share what's available, comparative surveys
Introduction to survey monuments and what instrumentation a typical dam might have (embankment versus concrete) and what we are trying to accomplish (what are we measuring, what accuracy are we trying to get)
Instrumentation - Where instrumentation is located on the dams and why

What does a good survey monitoring program look like at a dam?
- Earth Dams - Settlement, slope failure (sudden drawdown, instability), earthquake deformation (lateral spreading, liquefaction), internal erosion (surface monitoring)
- Concrete Dams and Concrete Appurtenances - Sliding, overturning, settlement, excessive deflection, structural failure/cracking
Importance of seasonal monitoring (specifically arch dams)
Elements of a reliable deformation surveying program
- Frequency of surveys (continuous, scheduled, event driven)
- Quality Control
- Presentation of Data
- Interpreting and acting on the data

Collecting and assessing data so you can act quickly if it's showing a problem
Case study of numerical model
Potential case studies lessons from the field:
- Wanapum - movement started 50 years after in service
- IP - survey points sitting in loose soil
- Monuments get moved - investigate error in the field
- May need to set new monuments in the field - line of sight issues
- Mining near a dam caused movement - years after normal performance
Becoming complacent over the years - then get differences - survey errors
Best Practices
- Do a survey after a seismic event
- Bathymetric survey after large flood