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Monitoring Surf Impacts - Save Our Waves!

Surf spots are a vital part of the United State’s culture and economy, and need to be protected to the fullest extent possible. An estimated 2.5 million Americans surf. Local surf trips account for up to $3.3 billion of the California’s coastal economy, according to legislative analysis, and the surf industry generates over $6 billion in United States annual retail sales

Unfortunately, between rising sea levels, seawalls, coastal
development, beach fill and more, our waves are under enormous threat. Despite
the economic contributions, and the beloved cultural and recreational role
surfing plays in the lives of so many, it often remains an afterthought in many
shoreline management and coastal development permitting decisions. Surfrider is
working to change that.

One important way we can inform future decisions is by monitoring the impacts to surf associated with development and shoreline alterations such as beach fill and seawalls. Afterall, seawalls and hard armoring are known to increase erosion and impact wave quality.

In 2012, Surfrider's San Diego Chapter undertook a great example of surf monitoring at key locations throughout the county in response to a regional beach nourishment program - details and the results of which are posted here.

Recently, at Surfrider’s request, the California Coastal Commission required that California State Parks monitor the impacts to surf and beach erosion associated with the 800-foot rock revetment placed at San Onofre State Beach. The seawall was placed in 2017 under an emergency permit and subsequently in June 2019, given a 5-year authorization. The 5-year authorization will be extended for another 5 years provided no substantial impacts are present based on the monitoring data.

The iconic San Onofre State Beach is known for its car culture of the 1960s and 70s. Is this culture worth preserving from erosion at the expense of wave quality?

Surfrider participated in a stakeholder driven process to
develop the monitoring plan along with the San Onofre Park Foundation, San
Onofre Surf Club and others. State Parks intends to bring in some of the latest
monitoring technology developed by UC Irvine and Surfline to come up with a
comprehensive, efficient and reliable plan for monitoring.

We spoke with Riley Pratt, Senior Environmental Scientist
with California State Parks Orange Coast District about the surf monitoring
plan he’s in charge of developing for San Onofre State Beach. Here’s what he
has to say -

SF: Why are we monitoring the surf and beach at San Onofre Surf Beach?

RP: There are number of reasons to monitor Surf Beach.  First and foremost, we are required to under our current coastal development permit, which authorizes the existing revetment for another 5 years.  Coastal Commission wants to be sure the coastal armoring they've approved isn't exacerbating beach erosion, degrading the surf resources in front of it, or causing any other negative environmental impacts.  You'll only be able to know if you're having an impact if you're monitoring for it. 

More broadly, monitoring is a key part of any adaptive
management program/system and is recognized as such by our Department and our
Natural Resources Program policies.  Monitoring allows one to track the
impact or effectiveness of their management actions and helps one decide when
to make a course adjustment.  In my opinion, it's an essential part of
being a good steward of State resources.

SF: What are some impacts we might expect to see from the
new seawall - what should we look out for?

RP: This is hard to answer because beaches – and surf breaks – are very dynamic systems to begin with.  They are constantly changing in response to many different but interacting forces (e.g. swell direction, wave strength, swell period, tides, currents, sediment transport, wind, etc.) that are operating at multiple time scales – hourly, daily, seasonally, and annually. 

A beach's susceptibility to change is also influenced by its position along the coastline, its proximity to new sand supplies (e.g. a nearby river), and its exposure to wave action. To complicate matters further, we're going to be experiencing accelerating rates of sea-level rise across our coastlines in the coming decades. So when we add something new to the system – like a rock revetment – it's hard to disentangle its effect from everything else that is changing the surf and shoreline.  That said, shoreline protective structures have been shown to impact beaches in some cases, including beach loss through passive erosion, loss of sand supply from inland bluffs, and alteration of recreational surf conditions. 

To date, we haven't observed these negative impacts at surf
beach. As the pace of sea-level rise increases, and the ocean
interacts with the revetment more frequently (currently, ocean water
touches the revetment only at about a +6 tide or higher), I would expect
to see more backwash in the surf zone at the highest tides.  But we may
see similar increases backwash up and down coast also where no shoreline
protection exists but where beaches are naturally eroding and waves are
reflecting off of a scarp face. That is precisely why monitoring the
existing revetment and nearby unprotected sections of surf beach is
important; to determine whether or not such effects are occurring.  

On the plus side, I expect the revetment to protect public
access to surf beach over the next 5 to 10 years, as well as many of the
public services enjoyed there (public safety, parking, restrooms,
freshwater, and trash collection).  The low adaptive capacity of surf
beach means new facilities and access routes to the beach will be necessary in
the coming decades. While State Parks intends to work on a longer term access
plan following the renewal of its lease with the USMCB, removal of the
revetment now would very likely lead to loss of public access in the immediate
term.  Wave hazard analyses for surf beach indicate the access road
at this pinch-point will flood every year without the existing revetment and
the magnitude of this annual flooding event will continue to increase with
sea-level rise. More flooding would likely result in greater road damage and
subsequent road closures, which would limit public access to the beach

These are tough trade-offs but I think we've made the
right decision.

SF: What are the shortcomings of beach and surf
monitoring - how reliable is the data we collect?

RP: I think the monitoring program for surf beach we're currently developing with our partners will generate very robust data and will allow us to capture the tremendous variability in conditions across space and time (which is super interesting as a scientist!), but I'm afraid it won't allow us to tease apart the effect of revetment per se on that variability.  To do that, you'd need a second surf beach experiencing the exact same external forces (swell, tide, wind, etc.) but without a revetment. Then, any change you observed could be attributed to the revetment.  That would be the ideal experiment but unfortunately, no such control spot exists.  Having a robust set of beach and surf data collected before the revetment was installed to compare with would have been the next best thing, but that data unfortunately doesn't exist. 

A good thing about starting the monitoring now, however, is
that it will provide a new baseline going forward.  So if we install any
shoreline protections in the future (e.g. cobble berm, sand nourishment, etc.),
we could compare the before and after condition. While I think it's safe
to say none of us at are happy about the challenges sea-level rise pose for our
coastlines, I'm excited by the opportunity to apply the best available science
to monitor the changes that are happening.

SF: How can folks get involved or give input on their

RP: We're working on this now and are open to input.  We may be able to utilize our existing social media platforms and parks websites to receive and share observations and input from the public.  I think doing regular public outreach at surf beach would also help.  Finally some of the monitoring we're proposing could be carried out by volunteers and/or local students. This would provide the public an opportunity to get involved with the monitoring directly and share those experiences with the broader community.  These benefits transcend the project itself; it is an opportunity to engage the public on present and looming coastal issues and climate change more broadly. 

So there you have it! Until this point, there has been no effort to monitor changes at San Onofre State Beach or develop a long-term management plan that will preserve the beach and the waves. A goal of this monitoring plan for Surfrider is to pair anecdotal evidence, which may be less reliable due to the wide range of surfing skill and experience of those reporting it, with observations from a consistent framework of surf spot monitoring - and use that data to inform a long-term plan for the park. We’re excited that these efforts are now underway. We here at Surfrider acknowledge that certain projects are important to local economies, coastal access and recreation, but we hold firm that those should not be constructed at the expense of other important resources, including surf. With each step forward, we are closer to our goal of protecting all of California’s ocean, waves and beaches.