Computation of dam freeboard for wind generated waves

Additional dam height is usually required to prevent wind-generated waves from overtopping a dam. If over designed, this additional height can be expensive. If under designed, it may not perform as intended. This freeboard amount is usually determined by computing a wave height based on a reservoir fetch and a wind speed. Other factors should be considered. The purpose of this paper is to discuss all technical considerations for the computation of wind generated wave run up on dams in order to more rationally assess freeboard adequacy. The topics include:
- Site specific wind data (speed, frequency, duration, and direction)
- Determining the appropriate wind duration
- Defining what wave height is being computed (e.g. significant wave height, deep water, shallow water, etc.)
- Computing the wave run up on the dam face

The frequency and the duration of the freeboard design reservoir elevation coincidentally with the frequency and duration of the design wind provide some indication of the risk of providing too much or too little freeboard. The information compiled is used to compute freeboard amounts for dams located in Atlanta, Georgia. However, the information presented can be utilized for application in other geographical areas. 12 pp., 4 references.