It is estimated as the number of values times the sum of the cubes of the deviations from the mean divided by the number of values minus 1, times the number of values times 2, times the standard deviation cubed. Damage is normally specified as a percentage of the structure or content value. The functions are generic for similar structures and are not tied to the structure location. Damage is the median estimate of structure, content, and other inunda- tion reduction damage associated with the stage of floodwaters at the location. These relationships are usually developed by computing water surface profiles for several discharges and plotting the stages vs. discharge relationship at a specific stream lo- cation.
Uncertainty is the distribution of the er- rors of stage estimates about a specific discharge.
Structural measures - Those water resources project measures designed to modify the flow of flood waters. Uncertainty - A measure of the imprecision of knowledge of variables in a project plan.