The AB947 bill, sponsored by Hanna-Beth Jackson, is blaming the disappearance of sand due to erosion from seawalls. Seawalls are hard protection devices, designed to stop the ocean wave up-rush that can damage a structure’s foundation. Most hard protection devices are rocks, cliffs, or any other natural impediment. California has approximately 1100 miles of beach comprised of various hard protection devices. AB947 is blaming only man-made seawalls on erosion when, in fact, seawalls include only a small portion of the 1100 miles of hard protection devices. Additionally, AB947 will exclude all government installed seawall or hard protection devices.
Historical aerial pictures of the California coastline reveal more abundant sand deposits on California beaches. Did the construction of the seawalls cause the sand to disappear? The obvious answer is “no” because seawalls comprise only a small portion of the coastline, and cannot make sand appear or disappear, but only direct or deflect deposit. The truth of the matter is that the sand has not disappeared due to erosion, but has never appeared due to choking of sediment/sand flow to the ocean from outfalls to the ocean. The choking of sediment/sand flow to the ocean is caused by constructed watershed and flood control systems. These devices include the covering of land areas with hard surfaces, dams, debris basins, channeling rivers and streams, inadvertently halting the natural flow of sediments, which are the basic building blocks of the California beaches.
AB947 is a bad bill because there have not been any scientific studies which substantiate seawalls causing erosion. The “California Coastal Erosion” draft, authored by Mary D. Nichols describes many other factors which contribute to erosion besides seawalls including: (1) the restriction of outfall sediment flow to the ocean, which replenishes beaches with sand on and near shore, (2) the natural erosion due to oceanographic and geologic conditions which also affect delivery and movement of sand, (3) the storm activity altering the coastal sand deposits with erosion, (4) the increased coastal population with development, (5) no existing statewide standards in place for handling erosion.
AB947 is proposing the removal, and the prohibition of any repairs of all privately owned seawalls by “a date-certain.” Mandating a “restricted life” to the seawall will result in loss of residential homes due to un-protected property by the up-rush of the ocean. It appears that AB947 is attempting to eventually re-claim private property for public use, without paying for it. AB947 is currently sponsored by such groups as the Sierra Club, Surfrider Foundation, and other organizations, who only would desire public access to private property. Other California property owners who are not located on the coastline believe that they will not be affected, but lenders, insurances companies, and other investors will be deterred due to this type of “crazy legislature,” causing devaluation within the entire coastal zone.
Alan V. Ruzicka
Consulting Engineer