An artificial reef is a manmade structure that may mimic some of the characteristics of a

natural reef. Artificial reefs may be built to enhance marine habitat, improve, or build a surf break, or encourage the dissipation of wave energy thereby protecting landward structures from coastal storms and wave runup.

The zone of the shore or beach above the high-water line, acted upon only by severe storms or exceptionally high tides.

A barrier built out into a body of water to protect a coast or harbor from the force of waves.

A groin is a coastal engineering structure, usually composed of rock, that is constructed perpendicular to the shoreline with the intent of retarding the loss of a beach and widening it by trapping passing sand. Some are built solid to be impervious to sand flow and others are built to be permeable, to allow appreciable quantities of sand to flow through.

A jetty is a coastal engineering structure that projects out from land, usually built from quarried rock, with the intent of maintaining a river mouth or harbor opening, protecting the channel or mouth from shoaling, or filling in with drifting sand. A jetty may be longer a narrower than a groin and is not part of a series of structures.

Item Littoral transport is the movement of sedimentary material along the shoreline by waves and currents.

A revetment is a passive structure, which protects against erosion caused by wave action, storm surge and currents.

This term refers to the act of dumping large quantities of sediment, or sand, onto a beach. Sometimes also referred to as sand “replenishment”.

The term “sediment” is the scientific name for sand. The word sediment can refer to the

grain, its size and quality, as well as the total sum of grains making up the beach.

Structures built to alter the effects of ocean waves, currents, and sand movement.

Oceanside beaches are part of a naturally eroding sandstone bluff coastline that stretches from Dana Point to La Jolla. Rivers and streams which have supplied beaches with coarse sand have been diverted or dammed. Coastal bluffs have been developed and protected with sea walls and large rocks restricting the natural addition of sandstone to the beaches. Waves, tides, currents, and severe storms sweep sand off the beach. Some of this sand is deposited on other beaches, but most of it is swept out to sea to settle in offshore canyons. Our naturally wide beaches are shrinking and, in some areas disappearing.

Multiple structures built throughout the 20th century impacted and continue to reduce Oceanside's sand supply:

• The damming of Lake Henshaw in 1922

• The breakwater and boat basin for Camp Pendleton in 1940's

• The Oceanside Harbor in the 1960s

Combined, these structures contribute to severe coastal erosion and beach sand loss in Oceanside.

California Coastal engineering experts and renowned coastal scientists have cited that while there are a number of important design considerations and precautions associated with retention systems, they basically mimic natural littoral drift barriers and become artificial headlands.

As such, they trap sand and either create beaches where they previously did not exist or stabilize or widen existing beaches.

Scientists have stated that a well-design retention system with effectively, incorporated downdrift mitigation design features, addresses concerns of natural littoral drift flowing, both to the south and north.

The proposed Oceanside solution includes design features that will mitigate the potential negative impact on downdrift beaches.

Prefilling/nourishing the area between the groins with sand is key to reaching an equilibrium state where sand will naturally bypass around the groin(s). Also, a proposed preliminary design of a sand bypass system is part of the solution. The sand bypass recovers sand that generally would not otherwise be available. It would be a permanent system to bring sand from the North of Oceanside to the South, to the groin system, and beyond. This sand would typically end up in the mouth of the Oceanside harbor or its usual terminus in the offshore canyons.

A properly designed and actively managed groin system will minimize or eliminate the negative impact on downdrift beaches. We do, in fact, have the expertise and science-backed knowledge to incorporate design factors that will mitigate negative downdrift beach impact.

Two design factors can be implemented to mitigate this issue:

• “Pre-charging” or filling the area between the groins with sand to accelerate the equilibrium state. This will cause some natural bypass flow of sand to downdrift beaches.

• An active replenishment and, most importantly, sand bypass system to ensure that sand does transport past the furthest South groin to the adjacent downdrift beaches. 

Oceanside City Officials, have repeatedly stated on the record, that this sand replenishment and retention pilot project would NOT be approved if it has a detrimental impact on neighboring downdrift cities.

While rip currents can form adjacent to sandbars, groins, and other manmade structures, lifesaving experts in Oceanside and Newport Beach both agree that shoreline structures do create a predictable location for rip currents to form. In fact, 80% of their beach rescues are a result of rip currents (Brewster et al., 2019). In knowing the location of the rip current, we can put in place sound and proven mitigation strategies for this risk. Posting signage with "no swimming" areas, placing lifeguard towers at the head of the groin, and providing public education and engagement by the lifesaving agency will ensure safety for all beachgoers on how to deal with rip currents safely. 

Most importantly, Southern California Beach Lifeguard Captains comment that the open-beach rip currents that occur ALL along the coastline are a significant safety concern as it takes a very experienced lifeguard to spot them. 

• If you are unsure of dangers on the shoreline – do not hesitate to ask a lifeguard.

• If you are unsure of dangers on the shoreline and there is no lifeguard on duty, do not go into the water.

• If you would like to learn more about what causes rip currents and how to protect you and your family from their dangers when hitting the beach, visit the United States Lifeguard Association website.

• If you would like to teach your child to become an advocate for beach safety, check out the Oceanside Junior Lifeguards Program.

Proper design can create access ramps up and down the groin parallel to the shoreline. This potential design feature would allow the ease of personnel passage up and over the groin till sand accumulates to allow for ease of passage. It also allows for access to emergency response vehicles up and down the shoreline. An example here is the Newport groins which extend all the way East to the housing. The accumulated sand buries them, and it is very easy for people walking the beach to get up and over the groin and provide safe access for emergency vehicles.

Nearshore sandbars are not static features but move in an onshore or offshore direction, depending on the wave climate. Sandbars come and go, often popping up overnight where they form two-way peaks where there was previously nothing but closed-out surf. These new sandbars can last a day or two or survive for a prolonged period. Although sandbars move and shift along coastlines continually, “there are consistent breaks on the north end of Oceanside, at the harbor's north and south jetties, and on both sides of the pier” (Surfline, Oceanside Harbor North Jetty).

Groins, in most cases, have been found to create and or improve surf breaks. In dialogue with local surf industry experts and surfers, they favor installing the groins to retain sand and improve surf. Several cited examples from coastal scientific experts and established surfing outlets state the following: 

• “This "hottest 100 yards" of Newport between 54th and 56th is traditionally known for defying surfing tradition and the crossed-up peaks that offer plenty of ramps. Thanks to the string of jetties that break up the sand flow, the shape of the waves -- particularly in front of these two streets -- tends to be favorable for high-speed surfing. There are three main peaks that peel inside the 54th Street jetty that take both S and N swells, making it consistently surfable throughout the year, but also consistently smaller than Huntington Beach, just a couple of miles north” (Surfline, Newport Jetties Surf Guide).

• "The groin field in West Newport resulted in the creation of new, consistent surf breaks. Some of the most popular surf breaks in Northern San Diego County result from coastal structures such as jetties, piers and groins (e.g. Oceanside Harbor, Oceanside Pier, and the warm water Jetty in Carlsbad)." (Griggs et al., 2019, p. 31)

• "Cross-Shore Structures such as groins, jetties, and piers, when installed on open sandy beaches, commonly create the conditions favorable for the formation of surfing breaks adjacent to it (i.e., Huntington Beach pier, Newport Beach groins, New Jersey groins, Sebastian INet jetty)" (Benedet et al., 2007, p. 14). 

• “Our favorite places to surf in Oceanside, as in line with Surfline's “Top Surf Spots & Beaches in Oceanside” are on the north and south sides of the Oceanside Pier and the north and south Oceanside Jetty - all are manmade structures that are surfers' top places to paddle out” (Oceanside Local Surfer - Testimonial). 

As part of the environmental review process, the existing surf conditions adjacent to the project can be both quantified and qualified based on data collection and input from surfers.

Continued expensive major replenishment events are not affordable nor sustainable. Dredge, pump, repeat…the same old story.

While beach nourishment (replenishment) events are considered an ecologically sound option for beach restoration, nourishment events also bring about significant changes in the sandy beach ecosystem. A large proportion of flora and fauna are destroyed by adding a thick layer of nourishment sand. (Speybroeck et al., 2006)

The engineers/scientists agree that living shoreline is not a sound option for the breaking wave  energy/physics of the Oceanside shoreline. There is a potential that once a substantial back beach is  established using replenishment and retention, a living shoreline could be considered for installation to  further anchor and protect the city assets and shoreline infrastructure. The living shoreline structure is  protective device vs retention device. A living shoreline such as in Cardiff is essentially an armored  shoreline/revetment buried by replenished sand. See below a cross section of the Cardiff Living Shoreline: 

Oceanside cannot accept managed retreat as an option. Although a nice-sounding idea to the coastal "purists", managed retreat is not feasible anywhere on the Oceanside shoreline. Where do we relocate the potentially targeted structures to? Even if we took the funding for the first part of the replenishment/retention plan, $51M – could you at best purchase 6-8 shorefront structures? Better to protect our shoreline with a broad back sandy beach.

Yes. Section 30235 of the Coastal Act states that “revetments, breakwaters, groins, harbor channels, seawalls, cliff retaining walls, and other such construction that alters natural shoreline processes shall be permitted when required to serve coastal-dependent uses or to protect existing structures or public beaches in danger from erosion, and when designed to eliminate or mitigate adverse impacts on local shoreline sand supply”.

The replenishment and retention system should have a regional view and dovetail with current and  future regional sediment management plans. Any engineered solution for the Oceanside shoreline will incorporate design features that address and mitigate downdrift beach/shoreline impact(s).

While it’s true that some people feel that coastal structures, like groins, are bad, coastal scientists, engineers, and planners do not generally agree with this blanket generalization. In the science of coastal processes, just as in real estate, the phrase “Location, Location, Location” is often the critical first step in determining whether the structure is worth pursuing. Further insights from coastal scientists state:

“Groins are deserving of more in-depth consideration as an important beach management and adaptation strategy, particularly in conjunction with beach replenishment.” (Griggs et al., 2019)

“In most cases, the effects of replenishment without retention structures are short-lived, with nourished beaches eroding over a few years, leading to costly cycles of replenishment.”  (Flick 1993, Wiegel 1994, Griggs and Kinsman 2016).

“The San Luis Rey River Groin, which was extended to 910 feet in 1968, has played an important role in helping to retain sand on the popular beach in front of the Oceanside Harbor for decades.” (Griggs et al, 2019).

“Considering that one purpose of the coastal act section 30235 is to protect public beaches, the placement of well planned and engineered groins, and if deemed necessary, the initial filling of the upcoast behind each groin to its full capacity (figure 13) may be consistent  with the Coastal Act.”  (Griggs et al., 2019, p.31)

Groins may protect a public beach, and preserve beaches for one of their most important uses; our recreation purposes.   Widening and stabilizing beaches along the Southern California shoreline would protect existing structures and beaches from erosion and have an overall positive effect in trapping some of the 1.4 million cubic yards of sand permanently lost to submarine canyons and the ocean floor each year.  (Griggs et al., 2019)

The concept is not new, nor experimental, as similar groin systems have been employed effectively for decades throughout the state and worldwide. The Newport Beach groin field is a prime example of the positive effect of groins. Additional local examples of jetties acting as groins are the South Harbor Beach Jetty, the jetties in Carlsbad and Ponto beach; all provide significant sand retention for those adjacent beaches.