Tidal Erosion

Steep banks of the Slough carved out by tidal erosion.

Tidal Erosion is the process by which tidal flows erode banks and channel beds, sometimes called tidal scour. The average rate of bank erosion along the slough’s main channel is twenty inches a year in the upper slough and twelve inches a year in the lower slough. The average width of tidal creeks has increased from eight feet to over forty feet in the last 70 years.

E. Van Dyke, K. Wasson and A. Woolfolk are working with collaborators at California State University Monterey Bay and the Monterey Bay National Marine Sanctuary to understand habitat changes that have occurred as a result of tidal erosion following the opening of a large artificial mouth to Elkhorn Slough in 1947 by the Army Corps of Engineers. They have documented substantial losses of salt marsh and changes to tidal creek structure.

For more information, download a summary report of the effects of tidal erosion at Elkhorn Slough (170KB / PDF).