Damming of rivers in California leads to beach erosion

Historically, where rivers enter the coast directly, they have been the primary source of sand for the beaches, When there is a seasonal balance of sand on the beach, the beach responds to wave action by adjusting its profile to dissipate the available wave energy. When there is a deficiency of sand on the beaches, waves attack cliffs and coastal property directly. The evidence supporting these simple relations is sometimes confused and complicated because of (i) the intermittent nature of the floods that bring the sand to the coast, and (ii) the interception of the longshore "river of sand" by structures along the coast. The deficit of sand due to dams is illustrated by the 0ceanside Littoral Cell where rivers now provide only 49% of their natural yield.Because of the dams, our coastline has a sand deficit and wave erosion is the natural consequence.