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entire Coastal Systems text book
Ch. 9 Coastal Ocean Food Resources
Ch. 11 Coastal Ocean Mineral Resources
Coastal Zone Recreation, Tourism and Beaches
Coastal zone recreation and tourism primarily focus on the shoreline environment, specifically the beach. Shorelines lacking an attractive beach setting will rarely generate the tourism that they might otherwise produce. Rocky coasts do attract people because of their rugged scenery, and harbors draw people for sport fishing, entertainment and small-boat recreation. The coastal zone of the Southern California Bight has a little of everything, and a lot of beautiful beaches, making it a primary destination for tourists from around the globe. The attraction of SCB beaches is constantly enhanced by movies and television shows that feature local southern California beaches, as well as old Beachboys songs that get radio play throughout the United States. This chapter of Coastal Ocean and Human Impacts will provide a few details about SCB recreation and tourism, then focus on the beaches of the Bight such as Laguna Beach below.
Recreation and Tourism
Recreation and tourism go hand in hand. As estimated by the Southern California Coastal Water Research Project (SCCWRP) in 2003, approximately 100 million people visit California beaches and coastal areas annually, bringing roughly nine billion dollars to the local economy. The 1999-2000 National Survey on Recreation and the Environment broke down recreational activity in coastal California in the following way:
12.6 million people
8.4 million people
4.2 million people
2.7 million people
coastal bird watching
2.6 million people
Based on the number of people living along the coast of southern California (15 million) and the vast numbers of tourists that visit annually, and the length of the shoreline here, it is estimated that for if every person visited the shore at the same time, they would each have 3/4 inch of beach to recreate on - tight quarters indeed!
A. Recreational Activities The primary recreational activities along SCB shorelines are surfing, diving, skating, swimming, beachgoing (sunning, volleyball and most anything under the Sun), camping, sport fishing (which generates more than a half billion dollars annually), and boating - there are more than 40,000 pleasure boats in the small-boat harbors/marinas of the Bight. Local harbors/marinas and piers are often focal points of tourism with clusters of gift shops, hotels and seafood restaurants adjacent to the harbor itself. Below are a series of photographs illustrating different aspects of beach recreation in southern California.
B. Impacts of Recreation Recreation/tourist impacts generally are mild in terms of their effects on the coastal environment.
1. Beachgoers and surfers may leave behind some trash, and suntan oil and sunscreen can wash off in the water or stick to the sand, but the pollution is superficial and short-lived. The photograph below shows a popular beach within Crystal Cove State Park, just north of Laguna Beach.
2. Sport fishing has only a minor effect on local fish populations, and the catch is carefully regulated based on the size of the fish/squid/lobster, and the number of animals taken. Note that illegal catches - where too many individuals are taken, when juvenile animals are caught before they can reproduce, and the removal of protected species - can undermine marine conservation goals and the health of a marine ecosystem. Enforcement of regulations by wildlife managers is critical to maintain the viability of local fishing grounds of the Southern California Bight.
3. Pleasure boats are sources of fuel leaks and toxins from anti-fouling hull paint. A study from 1973 (SCCWRP) showed that roughly 80,000 gallons of anti-fouling paint rich in copper was applied to boats on an annual basis in the late 1960's and early 1970's. Fortunately, non-toxic organotin has now replaced copper, but the residual copper from older paint is still being released by older vessels, and there are significant copper accumulations in the sediment of some small-boat harbors of the Southern California Bight.
4. Tidepools are delicate environments where organisms are already challenged by alternate periods of being underwater and then exposed to the atmosphere, a variety of predators, rapid changes in salinity due to evaporation and wave shock. Tidepool organisms can be severely impacted by human visitors who step on or handle them, and their numbers and diversity can shrink due to poaching. Tidepools along the coast of California are protected by state and local laws, which are often ignored due to a lack of adequate enforcement. Below is a sign informing visitors of tidepool regulations at the Point Fermin Marine Life Refuge.
Beaches of the Southern California Bight
Beaches are dynamic landforms that can change dramatically in response to wave and current activity, and the availability of sediment. Beaches have been well-studied all over the world, and nowhere more so than in California where they are the backbone of coastal tourism and a symbol for the lifestyle of many Californians. See the California Beach Restoration Study (2002) for a detailed look at the facts and issues related to California's beaches.
A. Beach Composition Beaches are composed of rocks and minerals derived from local cliffs and headlands, or from inland mountains.
1. Beaches are usually made up of sand-sized grains because larger grains (gravel, pebbles, cobbles, boulders) are typically not transported directly into the ocean by streams, the source of most beach sediment in the Southern California Bight. Smaller grains (clay and silt) introduced into the coastal ocean by streams are usually winnowed away by wave activity and carried offshore by currents. Below is a typical sandy beach of the Southern California Bight.
An exception to this rule on sand-sized grains and beaches occurs where cliffs are crumbling directly into the ocean. In that situation, the beach may be composed of pebbles, cobbles or even boulders. Shown below is such a beach at Palos Verdes Peninsula.
2. Most beaches are rich in the mineral quartz, which is a common and durable component of many rocks. Less common mineral components of SCB beaches are feldspar and mica, which are far-less durable than quartz. Note that these three minerals are abundant in the common igneous rock called granite, and that our local mountains (San Gabriel, San Bernardino and Santa Ana mountains) are composed mainly of granite. Surfside Beach, shown below, is composed of quartz and potassium feldspar sand grains. The gray quartz and red to brown color of the feldspar give the beach its light tan coloration.
3. The main sediment source for SCB beaches is our local mountains. As they weather and erode, streams as well as water traveling through storm-drainage channels transport clay, silt and sand-sized particles into our coastal zone. This accounts for about 75% of our beach sediment. According to Griggs (2006), over 99% of the sediment along the coast of Santa Barbara is from streams. The dominant sediment source for beaches south of San Clemente (southern Orange County) is from cliff erosion. Griggs underscores this statement, indicating that only 45% of the sediment in the southern portion of the SCB is derived from weathering and erosion of inland mountains.
Coastal-ocean sediment introduced by the Santa Clara River at Ventura clouds the water in the photograph below. This photograph was taken during March of 2005, the wettest year on record in southern California.
B. Beach Development Beaches exist because longshore current carries sediment from a source area (coastal headland or river mouth) up or down a coast within the surf zone. As this occurs, small to medium-sized waves push sediment ashore forming a sandy interface between land and ocean - a beach. On the other hand, large waves remove more beach sediment than they push ashore, causing rapid beach erosion. These processes can be related to the concept of summer versus winter beach profiles. Typically along the shores of the SCB, summer waves are small promoting widening of our beaches. Winter waves tend to be larger and more energetic, causing the narrowing and steepening of SCB beaches.
C. Coastal Cells Coastal sediment-transport cells exist where a large quantity of sediment enters into a coastal system. Typically this is where a stream flows into the ocean, but can occur where unstable cliffs release sediment into the nearshore, or littoral environment. Once the sediment is dumped into the ocean, longshore current carries the sediment along parallel to the shore. Eventually, sediment is funneled off shore as it drops into the head of a submarine canyon that extends shoreward into very shallow water. This marks the end of a coastal cell. An example of a Southern California Bight coastal cell is the San Pedro cell, which stretches from the Los Angeles River/Long Beach Harbor south to Newport Beach. (Before construction of the breakwaters of Los Angeles Harbor, the cliffs of Point Fermin, Palos Verdes Peninsula were the beginning of the San Pedro coastal cell.) Below is a diagram showing some features of the California Continental Borderland and the five coastal cells of the Southern California Bight, from Inman and others (2002).
D. Beaches Provide Passive Resistance to Waves Beaches act as buffers or shock absorbers against waves pounding on a shoreline. Their porous nature and mobility reduce wave force, protecting ocean cliffs or human developments from direct wave impact and destruction. Under natural conditions, beaches narrowed by large winter waves will widen during the rest of the year as small waves push sediment ashore. In the photograph below, large rocks that dropped from the cliff protect the toe of the Portuguese Bend Landslide on Palos Verdes Peninsula.
Problems with Southern California Bight Beaches
The main problems with SCB beaches are related to sediment, more specifically, does each beach receive an adequate sediment supply to remain wide enough for recreation and to protect shoreline structures from destructive waves. Problems associated with sediment distribution to the beaches of the Southern California Bight are explained below. Secondarily, human activities can churn up beach sediment, disturbing infaunal marine species.
A. Shoreline Modifications Modifications to a shoreline in the forms of groins, jetties and breakwaters interrupt longshore current flow and the distribution of sediment to beaches. As a result, some beaches are abnormally wide, and some are dangerously narrow, which can allow ocean waves, in conjunction with high tide, to break close to ocean-front property. This can result in destruction of homes and commercial buildings, and significant economic loss. An example of one of southern California's beaches with recurring erosional problems is Surfside Beach, a gated coastal community located near a jetty.
1. jetties Generally speaking, jetties are emplaced to protect the entrances to harbors. The jetties in the photograph below shield the entrance to Anaheim Bay and the Navy dock from ocean waves, as well as protecting small boats that are headed for Huntington Harbor. A review of many of the small-boat harbors discussed and illustrated in Chapter 9 reveals that jetties are fairly common features of the Southern California Bight's shoreline.
The photographs below show the coastal-ocean setting for Surfside. With regard to longshore current flow, Surfside is down-flow from the Los Angeles and San Gabriel rivers, the two main sources of coastal sediment along this stretch of California's coast. Unfortunately, jetties from the San Gabriel River outlet block longshore current that carries Los Angeles River sediment, and the Seal Beach Pier and jetties for Anaheim Bay block longshore transport of sediment from the San Gabriel River to Surfside. There, a combination of beach-sand starvation and occasional active wave-erosion events related to wave reflection off the jetty narrow the northwest end of the beach to dangerous width.
Surfside's beach becomes very narrow every four to seven years, requiring a major beach nourishment project to widen the beach and protect beachside homes. Each time the beach is artificially widened it costs taxpayers roughly nine million dollars, requiring three months of intensive offshore dredging and disruption of the ocean floor to accomplish. The following photographs illustrate the changes that occur at Surfside Beach, from wide (at end of a replenishment project) to narrow (due to starvation and erosion over a period of years), and then to beach replenishment (large dredge machine pumps sand onshore, through pipes and onto beach, with bulldozers spreading sand where needed).
2. groins Groins are relatively simple structures designed to slow the flow of longshore current, and thereby stimulate deposition of sediment along a particular stretch of a shoreline. Typical groins are composed of large boulders that form a wall that is perpendicular to the beach. As longshore current interacts with a groin, it must change direction, slow down, and drop much of its sediment load. Of course, the beach down flow of the groin will become starved for sediment and narrower. Eventually, sand must be physically transported from the broad-beach side of the groin to the narrow side to prevent the groin from being disconnected from the beach by wave erosion.
The photographs below are of a groin along the Ventura coast. In the first photograph you can see how the groin extends out into the surf zone. The second photograph illustrates how one side of the beach will widen as the other side narrows. From which direction does longshore current flow from?
The next photograph shows a groin field that serves to stabilize the shoreline of Balboa, a peninsula that extends from Newport Beach. Though referred to as jetties by locals, these groins have served this beach community well, maintaining wide beaches that generally keep destructive waves away from the densely populated backbeach areas. Construction of the groins was deemed critical after a major storm in 1965 eroded 165 feet of the beach, requiring an emergency wall of sand bags to protect the houses nearest the ocean.
3. breakwaters Breakwaters are very expensive to construct, with current cost being roughly one million dollars per linear foot. Typically, breakwaters are built to break the force of incoming waves in order to form an artificial harbor. Such is the case with the Middle and Long Beach breakwaters of Long Beach Harbor shown below.
On a smaller scale breakwater barriers can be situated offshore, which slows longshore current flow leading to deposition of sediment behind the breakwater. An excellent example of this usage for a breakwater is shown in the photograph of Venice Beach below. Here, the breakwater is widening a stretch of beach where recreational and commercial facilities exist. The groin to the right, which is in the downcoast flow direction for longshore current, also helps to widen and stabilize this portion of Venice Beach. Note that the beach downcoast from the groin is much narrower, making it a likely candidate for expensive beach replenishment in the future.
4. The shoreline modifications described above alter the flow of longshore current, thereby affecting beach dynamics. The simplest and least expensive shoreline modification is called a revetment, where large boulders or chunks of concrete are laid onto a shoreline, armoring it from the erosive nature of ocean waves. These revetments protect houses along a beach from destruction (as at Surfside Beach discussed above), and can also be laid along the base of ocean cliffs to slow their erosion and retreat. The negative aspects of employing revetments is that wave energy tends to be deflected to another part of the shoreline, possibly accelerating erosion or damage there. Also, armored cliffs do not contribute sediment to the coastal ocean. This can be critical where a coastal cell is largely supplied by sediment from coastal cliffs, like the Oceanside cell in the Southern California Bight. The photograph below shows a small revetment constructed to protect the south end of Peninsula Beach from wave erosion. Obviously, this revetment needs to be extended, but how far?
B. obstructions to delivery of terrigenous sediment to the coast Dams and debris basins constructed upstream from the coast intercept and trap sediment destined for beaches. This is true for many coastal areas on Earth, and especially for the coastal zones of the Southern California Bight. Over a period of many years, these obstructions will cause beaches to shrink in size as their primary source of new sediment is cut off.
1. Since 1950, sand has been trapped by dams constructed for water supply, flood control and debris containment in southern California. As of 2000, there are more than 300 dams across streams of southern California. Most of these dams are small, designed to trap sediment from damaging debris flows before they can travel into foothill communities. Water from streams and debris flows is allowed to percolate underground from surface settling basins, recharging shallow aquifers, or flow down slope into Los Angeles Basin drainage channels and eventually to the ocean. After one or more debris-flow events, the sediment is removed by heavy equipment and taken to a location where it can be of use. These debris dams are effective and essential aspects of hazard control for many communities, but they play a major role in starving SCB beaches of sediment. The first photograph below shows Morris Reservoir, an important San Gabriel Mountains reservoir that holds water for future use. Morris and similar reservoirs trap so much sediment that they must be emptied of water and cleaned out on occasion. The second photograph show a small debris dam that protects downslope property from debris flows.
2. Actually, SCB beaches should be much narrower than they are now, but the cut off of sediment by inland dams was offset by construction/dredging of marinas/harbors from Santa Barbara to San Diego from the 1940's through the 1960's. Dredged sediment was used for land-fill, or placed into the coastal sediment-transport system. The latter use has helped to maintain the widths of most beaches in the Bight.
3. In the future, expect our beaches to become increasingly narrow as the sediment budget for SCB beaches decreases, and for local governments to spend greater amounts of money to maintain beaches for property protection, tourism and recreation.
C. The cleaning or grooming of SCB beaches has reduced their ability to sustain macrofauna invertebrate communities, and by extension healthy shorebird communities. The grooming is common on heavily used public beaches, where a variety of solid trash such as cigarette butts, bottles and cans, paper, plastic toys and containers, and almost anything imaginable is left behind by beachgoers. Grooming may be surperficial, where a large rake is dragged behind a tractor, but more typical is where a mechanical sifter plows through the upper six inches or so of the beach. Sifters remove most trash items, but have a negative impact on invertebrate infauna (organisms that live within beach sediment).
1. Invertebrates like amphipods and beetles that live within sandy beach sediment derive most of their nourishment from carbon and organic material deposited on SCB beaches. The primary source of carbon/organic matter on beaches is from kelp and seagrass washed ashore by waves, called wrack.
2. Grooming of beaches by sifting machines efficiently removes wrack, which in turn drastically reduces the abundance of beach infauna. One study indicates that nine species of wrack-associated macrofauna occurred in natural, un-groomed beaches, while only two species were present in groomed beaches. Most shorebirds, like plovers, dine on infaunal invertebrates. If the invertebrates are not present, the birds move elsewhere thereby diminishing the coastal ecosystems of groomed beaches. Below are photographs of some of the variety of beach grooming machines used on beaches around the world.
Daily, M.D., Reish, D.J. and Anderson, J.W., 1993, Ecology of the Southern California Bight, University of California Press, Berkeley and Los Angeles, California, 926 pages.
Dugan, J.E., Hubbard, D.M. and Page, H.M., 2002, Ecological Effects of Grooming on Exposed Sandy Beaches of Southern California, in California nd the World Ocean'02, p.824 - 826.
Eichbaum, W.M. and panel, 1990, Monitoring Southern California's Coastal Waters, National Academy Press, Washington, D.C., 154 pages.
Griggs, G.B., 2001, California's Beaches: Lessons from the Past and Recommendations for the Future, California Coastal Coalition Conference.
Griggs, G., Patsch, K. and Savoy, L., 2005, Living With the Changing California Coast, University of California Press, 540 pages.
Inman, D.L., Masters, P.M. and Jenkins, S.A., 2002, Facing the Coastal Challenge: Modeling Coastal Erosion in Southern California, in California and the World Ocean '02, pages 38-52.
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