Question

To obviate current beach erosion potentials and as a part of beach re-nourishment, Research department’s Dr. Smith proposed a construction of a series of submerged wave energy dissipation structures (=submerged-plate breakwaters) at 110 ft from the shoreline of the Beach. Based on design specifications of the structure, the distribution of the number of waves dissipatable by the proposed structure per hour could be approximated by a normal distribution with a mean of 189 waves and a standard deviation of 7 waves.
1) Use the Empirical Rule to describe the 90% distribution/range of X, i.e., the number
of waves dissipatable by the proposed structure per hour.
2) If the structure is built with dissipating a maximum 195 waves/hour capacity, what
fraction of an hour, i.e., minutes, might the structure be unable to handle incoming
waves (or in other word, how many minutes per hour the structure exceeds 195
waves/hour capacity)?
3) What wave dissipating capacity of the structure should be built so that the
probability of the incoming waves exceeding the structure capacity is equal to only
0.05 (or 5%)?

Answer 1

1) Use the Empirical Rule to describe the 90% distribution/range of X, i.e., the number
of waves dissipatable by the proposed structure per hour.

2) If the structure is built with dissipating a maximum 195 waves/hour capacity, what
fraction of an hour, i.e., minutes, might the structure be unable to handle incoming
waves (or in other word, how many minutes per hour the structure exceeds 195
waves/hour capacity)?

3) What wave dissipating capacity of the structure should be built so that the
probability of the incoming waves exceeding the structure capacity is equal to only
0.05 (or 5%)?