The Case Against Shoreline Armoring

This is a historial post from Hiking the California Trail, a 1998/2002 book set by Bob Lorentz and Richard Nichols. Where possible an update has been provided.

Shoreline erosion occurs as a natural process. The planet’s surface shifts in a dynamic, ever changing interplay of wind, water and earth. This constant movement plays out most dramatically and rapidly on the shoreline, creating circumstances for disaster. Crashing waves, exposed geology, fresh air, sandy beaches, and vivid scenery attract millions of people to the California coastline. The problem: some like it so much that they build their homes or businesses directly on this rare, shifting, restless and hazardous shore. If it’s not private property owners challenging nature for the views, then the state builds roads in unstable places and spends millions to protect them.

Once we have made the mistake of building in hazardous locations, engineering steps up to solve the problem, but not always with satisfactory results. When the Mississippi River flood of 1993 overwhelmed millions of acres of farmland and many towns, causing $15 billion in damage, the Army Corp of Engineers admitted that $50 billion spent on dikes over more than 100 years did not solve flooding problems. The solution proposed for this failed policy: it’s cheaper to buy out flood-prone property and let the river return to its natural cycle of flooding.

On the California coast thousands of structures sit directly in the path of unstoppable natural forces. About 950 miles of the 1100-mile-long shore are actively eroding. Along 125 miles of that shoreline, erosion threatens structures. The solutions used to protect the inappropriate development generate more mistakes. Owners and/or the state install piles of unsightly boulders (riprap), or cold concrete seawalls to stop erosion. Groins and jetties stick out into the surf and inland dams clog rivers. Such interference with natural process is disastrous and costly. The dams stop the flow of sand particles from inland, starving the beaches. The jetties and groins stop sand flow along the beach, called littoral drift. The seawalls create a barrier to wave energy disbursement, causing a backwash that scours the shore of sand. Shoreside buildings are threatened, leading to costly repairs or construction of more seawalls and expensive sand replenishment projects. This all comes at huge expense to the public. The beaches simply disappear under a barrage of rock or concrete. The public loses the legally mandated right to walk the shoreline while their taxes often pay the bill.

There are only three ways to cope with erosion damage to structures: continue hardening the shoreline, replenish beach sand on a regular basis, or retreat. Hardening and replenishing are short term solutions that need continual maintenance and/or repair. The ocean’s constant dynamic forces continue to batter such defenses. Retreat remains the only real long term solution; surrender to the forces of nature. It’s time to halt all shoreline development and move or tear down threatened structures. Presently California state law allows seawall construction, if a structure is threatened, as well as repair and maintenance of seawalls. On the Pacifica shoreline south of San Francisco, soft sandstone bluffs rapidly erode, threatening a row of homes. Construction of a 1000-footlong seawall at the base of the bluff directly on the beach gained government approval. The public gets stuck with the bill, losing a beach in the bargain.

Government should buy threatened structures and tear them down, allowing the open-space bluffs to retreat as nature dictates. This solution seems difficult and harsh but in the long term saves money and our beaches.

The opposition to seawalls grows daily as the public sees more beaches lost. Until elected officials make the hard decision to end seawall construction, rezone threatened shoreline areas to open space, and move or remove threatened buildings, we will continue to see damage to the coastal environment for the benefit of the few coastal landowners at the expense of the citizens of California.

Originally Published in Hiking the California Coastal Trail: Guide to Walking the Golden State's Beaches and Bluff from Border to Border - Volume Two: Monterey to Mexico by Bob Lorentzen and Richard Nichols
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