Groaning Over Groins: Our Position on Sand Retention Strategies in OceansideBy SFSDAdministrator
The City of Oceanside will host a second virtual public sand retention workshop on Wednesday June 30 at 6 PM in order to discuss a number of alternatives for restoring sand to the city’s beaches. Surfrider expects the workshop to focus on a recommendation for a new groin south of Oceanside Pier. Surfrider does not support groins, and we've put together some background information on this locally charged issue for those who want to speak up and support their local Oceanside beaches.
How Oceanside’s beaches disappeared
Before we get into the merits or pitfalls of groins, let’s get some context:
- Oceanside Harbor and the Del Mar Boat Basin were built by the federal government in 1963 and 1942 respectively. They have contributed to significant sand loss in Oceanside by interrupting the natural north-to-south flow of sand in this area, as illustrated by the related breakwater jutting out from the coast in this blog's banner image (State of the Coast Report: San Diego Region, Volume 1, page 6-10).
- Regardless of the impact of the harbor and boat basin, coastal development in Oceanside was built too close to the water for beaches to thrive under regular storm conditions or sea levels that have incrementally risen over the last hundred years. Marine erosion of beaches was "locally severe" in 1929, 1940, and 1941 before the boat basin and harbor were constructed. Properties at Saint Malo were severely damaged in the storm season of 1940-1941. More recently, storms in the early 80's caused significant storm damage to many waterfront properties including the Strand (Coastal Cliff Sediments, San Diego Region, page 5-122).
- San Diego’s beaches have been eroding for thousands of years. Only in the last century have people started setting a back to the beach by developing property on naturally shifting coastlines, and then further protecting development in place with concrete seawalls and strings of large boulders called ‘rip rap.’ These flood protection devices change the way waves refract back to sea, which causes erosion and contributes to the narrowing of Oceanside’s beaches.
- Oceanside’s complex coastal topography and engineered coastline means that specific areas are naturally susceptible to periodic sand changes caused by storm activity. The City has been ‘opportunistically’ placing sand on certain beaches since 1963 (Sea Cliffs, Beaches and Coastal Valleys of San Diego County, page 56).
- Observed changes in sand dynamics are a result of natural processes but also of the impact or absence of sand placement projects.
Oceanside’s beaches are narrowing overall due to a combination of factors, including the fact that the City’s coastal boundary has been sited in an unsafe area. Surfrider does not believe that efforts to engineer a tidal equilibrium to suit this development pattern benefits the majority of public beach users or the public beach.
The Strand in 1979 and 1980 after storms. Sea Cliffs, Beaches and Coastal Valleys of San Diego County, page 58
Our position on groins as a sand retention strategy
Let’s get out with it — Surfrider is not for groins in Oceanside. We want to enjoy beaches south of the Oceanside pier as much as anyone else. However, groins are an engineering strategy of days past that have been widely criticized for their crude impacts to waves and regional beach management. Even the United States Army Corps, the builder-of-things on the coast, describes groins in its Coastal Engineering Manual as “probably the most misused and improperly designed of all coastal structures (Coastal Engineering Manual, V-3-59)."
Groins are long ‘fingers’ of concrete that stretch perpendicular to the coast, which build up sand by blocking its path. Groins do not create sand, they stop sand. In this stretch of coastline, where sand generally moves north to south along the shoreline from San Clemente through Del Mar, this means that sand unnaturally trapped in Oceanside is sand robbed from cities farther south. It is unlikely that the City can offset the ongoing negative impacts of downcoast erosion through artificial beach nourishment. Putting sand on beaches is becoming exponentially more difficult and expensive for all cities as sea levels rise and demand for sand increases.
Unfortunately, one groin in Oceanside will almost certainly beget the need for more groins in Oceanside as well as more of the structures further South. The California Coastal Commission, the quasi-judicial state agency that balances coastal access with private property rights, hasn’t permitted a new groin in California since 1998 because of their extensive impacts on downcoast erosion and on coastal resources. As a 2019 San Diego Union Tribune article puts it, “The Coastal Commission generally frowns upon seawalls, revetments and groins. Numerous studies have shown the structures can contribute to erosion and cause more problems than they solve.” Cue our next big problem with this strategy: Groins destroy waves.
Yes - groins may also create waves that peel off the structure itself, but by interrupting sand dynamics so intensely (that is literally what groins are designed to do), groins have unknown impacts to pre-existing waves. Groins have been known to destroy beach breaks, which rely on particular sand arrangements on the ocean floor.
Oceanside is avoiding the cause of its sand problem
At Surfrider San Diego, we are not willing to sacrifice the region’s awesome natural waves just because the City cannot move past a ‘build-something-to-fix-it’ paradigm. It’s because of this ideological roadblock that the Sand Retention and Feasibility Study being presented this week was directed to focus only on multi-million dollar options for engineering sand onto the beach.
The beach replenishment option that the City continues to avoid is comprehensive long-term planning for relocating assets from the coastline so that beaches can naturally move landward and coastal development is not repeatedly threatened. Most recently, Oceanside’s City Manager demonstrated the City’s overall position on relocation in a Voice of San Diego article, stating that “managed retreat isn’t something that will have to be implemented for at least another 20 years.”
That’s certainly true if you want your response to an impending disaster to be the decade after it hits. With flooding days expected to drastically increase in 2030, Surfrider and other organizations continue to remind San Diego’s local governments that the next ten years represents the only time period that cities can initiate any proactive planning for drastic sea level rise.
Global coastal flooding days caused largely by sea level rise and storm surge will increase drastically around 2030. Oppenheimer et al, 2030.
Other city decisions seem to point towards a preference for development over preservation of the public beach. Most recently, Surfrider called the City of Oceanside out for making it easier for homeowners to maintain private perched beaches behind riprap revetments that should become public lands as sea levels rise. (In California, everything seaward of the mean high tide line is legally public land, and the public's beach should therefore be migrating inward as seas get higher.) The California Coastal Commission invoked a formal dispute resolution process in March in order to investigate this decision.
We need long-term planning to restore sand and beaches to Oceanside
Surfrider recognizes the need for sand restoration options in Oceanside. We believe this starts with responsible, long-term planning that benefits the majority of residents along with public beach users. In the short-term, we understand that artificial beach nourishment solutions will continue to be relied upon, and we support community requests to hire a dedicated planning position for managing the coastal zone.
We encourage you to voice your position on this topic at the City’s upcoming public meetings:
- June 30,2021 - 6 PM, Sand Retention Workshop, Passcode: BEACH
- August 11, 2021, City Council Meeting, Agenda and Livestream Link TBA
For inquiries about our position, email us at Beachpres@surfridersd.org