An ephemeral river is a seasonal river that flows into the ocean, forming an inlet at certain times of the year, and the river is blocked by a barrier beach that usually forms a lagoon during the rest of the year. Ephemeral rivers are important for both military and civilian communities because these areas are susceptible to rapid, unpredictable flooding and beach breaching. Wave overtopping of barrier beaches is the first step to modeling beach breaching. Carmel River State Beach, in central California, acts a barrier beach for the Carmel River that flows into the Carmel Lagoon. Lagoon height changes were converted to volume changes by a stage-volume curve, then center differenced and averaged to provide total volume rates of change in the lagoon. The van der Meer and Janssen (VJ), European, and Hedges and Reis (HR) overtopping models were compared. The lagoon volume rate of change was compared to the predicted model rate of change for three different overtopping cases in 2006, 2008, and 2009. The models performed similarly with R² values of 0.72-0.86 for narrow banded cases, with an average reduction factor of 0.

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http://archive.org/details/waveovertoppingo109454551

US Navy (USN) author.