The beach just north of Lighthouse Point in Santa Cruz in February 1998 and in October 1997. What winter waves take away, summer waves may return.

THE COAST of California is under attack from the front and from the rear, from the ocean and from land. As storm waves and a rising sea level eat away at beaches and bluffs, fortifications are built at an ever more rapid rate to hold back the ocean, creating a dilemma of increasing magnitude.

The 1982-83 El Niño was a wake-up call - more than 3,000 oceanfront homes and 900 businesses were damaged - and the milder 1997-98 El Niño served as a reminder: Trapped between an ever more densely developed shoreline and the encroaching sea, California's parks, headlands, open spaces, and wetlands can be expected to dwindle at an accelerating rate unless there is a drastic change in coastal management.

The ongoing processes of cliff retreat and beach erosion, including the role that major oceanic events like El Niño play in them, have only recently begun to be recognized and appreciated. The California Coastal Act of 1976 is notably deficient regarding these coastal hazards. When that law was shaped, these problems were less apparent than they are now, and concern was focused mainly on public beach access, wetlands, and open space.

In the past two decades, both the impacts of coastal hazards and our perception of them have changed markedly. Major storms caused an estimated $150 million in coastal damage between 1978 and 1983, not counting the day-to-day cumulative effects of waves and other forces on the shoreline. In the 1982-83 El Niño year alone, coastal storm damage totaled some $100 million. Preliminary estimates from the 1997-98 winter indicate about $50 million in coastal damage.

As public and private attempts to fortify the shoreline increased, so did the expense. From 1985 to 1990, about 45 miles of coast were armored with seawalls, riprap, and other hard structures, at an average cost of $1,500 per foot, or about $60 million a year for new hard structures, not including expenditures for repair of roads, public stairways, and private property. Californians today are paying more than $75 million a year on average to maintain a foothold on their shoreline.

While "El Niño" is a relatively recent addition to most Californians' vocabularies, there is every reason to believe that the phenomenon has occurred periodically for thousands of years, if not longer. Historic records in Peru document its devastating impact for at least 400 years.

One of my Ph.D. students at the University of California, Santa Cruz, has been sifting patiently through global oceanographic and meteorologic data bases for the period 1910-1995 to study the impact of El Niño events on the coast of California. He has found that 22 El Niño events of differing severity occurred in this 85-year period, coming about every four years. Twenty of these coincided with larger waves, higher-than-normal sea levels, above-average rainfall, and coastal storm damage. Within this period, 75 percent of the storms that produced major damage along the central coast occurred during El Niño winters. It is important to realize that these global climatic events are not uncommon acts of God, and that they didn't start in 1983.

The 30-year period prior to 1978 - during which much of the construction along the California coast took place - is now believed to have been a period of relatively mild climate. The cumulative costs of storm damage were relatively low. In the past 20 years, however, more severe storms, leading to increased shoreline erosion, have substantially increased both the damage and the cost of protection.

Nearly a decade ago, Jim Pepper, Martha Jordan, and I conducted a study, California's Coastal Hazards: A Critical Review of Existing Land Use Policies and Practices (1992), funded by the California Policy Seminar Program. We had intended to bring the results and our recommendations to the state legislature, but the Loma Prieta earthquake intervened, seismic issues claiming center stage. Our findings never- theless remain timely today.

We found that despite a growing body of scientific information on coastal hazards and their associated risks, oceanfront development continued in unstable areas. We also found a wide disparity in the manner in which local governments and state agencies dealt with bluff retreat or other coastal hazards, indicating a lack of guiding direction and the heavy influence of local economics and politics.

Oceanfront development and shoreline erosion continue, putting more infrastructure and growing numbers of public and private structures at risk. Property owners and government agencies have had three basic options when confronting this risk: (1) remove or relocate the threatened structure, (2) nourish the beach, or (3) armor the shoreline.

We can retreat by either demolishing structures or, if an alternative site exists and the owners can afford the expense, moving them farther inland. Two oceanfront houses were moved recently at Depot Hill in Capitola, for instance, and at least one more was moved at Big Lagoon in Humboldt County after a major bluff failure. Generally, however, property owners fight to protect their homes and views, in place, at great cost. For them, and for public beach advocates, beach nourishment has emerged as an attractive alternative. Whether it can achieve the intended goals, however, depends on many site-specific factors.

The economics of beach nourishment, including who pays the costs, and how long the material brought to the shore remains there are factors that have blocked proposals in California, particularly where littoral drift rates are high, that is, where the sand is in continuous transit downcoast. In discussing such projects, it's wise to consider why a need for nourishment has arisen. In southern California, where beach loss has become a significant issue, the major reason for the loss has been known for years: As dams and reservoirs were built throughout coastal watersheds in the first half of the century, the sand that streams formerly transported to the coast became trapped. In a number of cases - Gibraltar Dam near Santa Barbara, for example - the dams no longer fulfill their intended purpose because the reservoirs behind them are filled with sand. The sand is still in the system, it's just in the wrong place. Before we invest vast amounts in searches for new sand supplies and in complicated short-term plans to nourish eroding beaches, perhaps we should look at the natural sources and transport mechanisms again. Why not remove some useless dams from coastal streams?

The most common approach to protecting property from coastal erosion has been to build seawalls or other hard structures. Currently, about 130 miles (12 percent) of the entire California coast has been armored, and a flood of permit requests for new structures and repairs comes after every major damaging storm.

Now is the time for the California Coastal Commission and other agencies to look carefully at the past and future of this approach. Some of these structures have been successful in protecting property, but others have proved to be no match for the ocean. The massive O'Shaughnessy Seawall backing Ocean Beach in San Francisco has survived for 70 years. To replace it today would cost $5,000 or more per linear foot. The 3,100-foot Great Highway Seawall, modeled after the O'Shaughnessy wall and built just downcoast on Ocean Beach in the early 1990s, cost $4,700-$8,000 a foot, depending on how much was built at one time, with the smallest (120 feet) section being the most expensive. Newer structures have cost $1,000-$3,000 per foot, or $5-$15 million per mile - considerably less than the O'Shaughnessy Wall, but their design and materials differ. Some may not stand for nearly as long.

In striking contrast to the O'Shaughnessy wall is the timber bulkhead and seawall at Seacliff State Beach near Santa Cruz. It has been rebuilt and subsequently damaged or destroyed seven times in 60 years. When last reconstructed, in the fall of 1982, it was expected to stand for at least 20 years, protecting a parking area. Two months later, storm waves damaged it so severely that the repair cost mounted to half the reconstruction cost. There is a lesson here: Either build a wall that can endure the environment or consider other options. Perhaps it is time to move the parking area inland.

Seawalls and revetments are controversial for several reasons. Not only are they costly and often ineffective, but they also have aesthetic and other impacts on beaches. Almost 30 percent of the coastline of Santa Cruz County and close to 65 percent of Ventura County's coast - to name but two instances - have now been armored. It's difficult for a beachgoer not to notice this much rock and concrete along the shore. A vertical, relatively narrow seawall will take up a very small amount of beach, but a riprap revetment, to be stable, may have to extend 20 to 40 feet seaward from the foot of the bluff - in some cases completely covering the usable beach area. Where such a structure is built along a shoreline that is undergoing long-term net erosion, the effect will be the gradual loss of beach in front of the structure as the shoreline migrates landward beyond it. Private structures may be temporarily saved, but the public beach is lost.

How such structures work on California beaches depends in part on local conditions. My research team at Santa Cruz recently completed an eight-year study monitoring the impacts of several different types of seawalls and revetments on fronting and flanking beaches in northern Monterey Bay. We found no permanent effects on the beaches studied, which are along a coastline that has no net long-term erosion. The impacts of a seawall on a shoreline undergoing erosion - the Fort Ord area of central Monterey Bay, for example, or the area south of the Half Moon Bay breakwater - would be very different and ultimately would lead to beach loss as the shoreline to either side of the wall retreated, leaving a protected peninsula without a beach.

Coastlines are getting increasing national attention as their economic and recreational importance grows and as shoreline erosion continues. Most protection structures to date have been financed by federal, state, or local funds or through insurance settlements, with statistics on beach usage and tourist dollars often invoked to justify such "coastal protection." But "beach erosion" and "shoreline erosion" are not the same thing. Seawalls and revetments are not built to protect public beaches; they are built to protect property and structures on dunes, bluffs, or cliffs. To my knowledge, a seawall has never been built to save a beach.

If California is to enjoy the many benefits of sandy beaches in the future, it must develop a realistic policy on coastal hazards and resist the pressures that permit continuing development in hazardous areas, as well as structures that may protect shoreline properties, but only at the beaches' expense. 

Gary Griggs is professor of earth sciences and director of the Institute of Marine Sciences at the University of California, Santa Cruz.