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Adapting to sea level rise requires trade-offs – and money. Imperial Beach, is one of the poorest coastal communities in Southern California, will need to decide whether to prioritize the economic benefits of tourism and beach recreation over maintaining the ecological value of beach and preserving existing flora and fauna, versus simply protecting buildings and property along the coast.
Imperial Beach is surrounded by water on three sides: the Pacific Ocean to the west, the bay to the north and the Tijuana River to the south.
That means it’s always endured storm surges and cross-border pollution, but the city is now coming to terms with another environmental reality: rising sea levels that could eventually impact 30 percent of the city’s properties, 40 percent of its roads, an elementary school and more.
The National Oceanic and Atmospheric Administration predicts sea levels could rise up to six and a half feet by 2100, a projection that would be dire for Imperial Beach. Erosion, flooding, wetland inundation and storms would all increase in frequency and intensity.
The city’s mayor, Serge Dedina, looked at El Niño this year as practice. High tides advanced on Imperial Beach homes and businesses, flooding coastal roads. The city lost 12 feet of sand, valued at more than $3 million, Dedina said.
David Revell heads a consulting team studying Imperial Beach’s climate change issues. He works in similar coastal communities across the state and said Imperial Beach is among the most vulnerable.
“You have estuary flooding that can happen when the beach closes,” Revell said. “You can cause bay flooding with king tides. You can have ocean flooding with high tides.”
At a recent City Council meeting, Revell referred to the El Niño storms and flooding residents faced a few months ago.
“Those storms will come again,” he said.
With elevated seas, he said, those storms will cause more damage and come more often.
“This work is not done,” Revell said. “It’s the start of it.”
Dedina and Imperial Beach’s City Council are trying to act, but it won’t be easy or cheap.
“People in IB have embraced that this is coming,” Dedina said. “But how often do politicians have to make policy to plan for 100 years in the future?”
The city of San Diego last year passed a plan to slash its contribution to climate change, but it pushed off planning for how to adapt to imminent changes — like sea-level rise.
Imperial Beach doesn’t have a climate action plan. Dedina said the best the city can do is conserve nearby wetlands. With just 26,000 residents, it doesn’t have the money for things like building electric vehicle charging stations.
Instead, it’s figuring out how to adapt.
At the end of the month, Revell’s team will tell the city how it can protect its beach, infrastructure and residents from sea-level rise.
But adapting to sea level rise requires trade-offs – and money.
With a roughly 30 percent poverty rate in neighborhoods along the bayfront, Imperial Beach is one of the poorest coastal communities in Southern California and one of the lower-income areas in San Diego County.
The city will need to decide whether to prioritize the economic benefits of tourism and beach recreation over maintaining the ecological value of beaches and preserving existing flora and fauna, versus simply protecting buildings and property along the coast.
If recreation and ecology are most important, the city can opt to maintain wide beaches to blunt coastal erosion. If it’s about protecting beachfront homes, a seawall behind a narrowing beach would do the job.
But a 40-foot seawall to protect beachfront property from eroding waves cuts against the value of the treasured property – beach access and oceanfront views.
Timing matters, too.
In the short term, solutions must deal with the flooding in our lifetime. Long-term solutions protect the next generation of Imperial Beach residents from even higher sea levels.
And the most effective short-term solution isn’t effective in the long-term.
Sand nourishment – imported sand to create a new beach or widen an existing one – ends up having the highest net benefit up until 2047. But buying and transporting sand gets expensive – especially once other coastal communities need to start adding sand to their own beaches.
But that isn’t the only trade-off Imperial Beach is considering. It also needs to weigh two different environmental problems against each other.
Imperial Beach has a natural gift to help protect it from coastal erosion. During storms, the Tijuana River carries sediment and deposits it on the shores of southern Sea Coast drive. It’s natural – and free –sand nourishment.
But the Tijuana River also carries pollution from Tijuana, Mexico, and deposits it in Imperial Beach. So for years, the city has tried to keep the sediment from ever reaching its beach. As the city pursues hotels and tourism, it’s been especially important to keep river sediment from reaching the city.
Revell says the most cost-effective way to deal with sea-level rise and maintain city beaches in the long run is “managed retreat” – that is, let the beaches erode. As they do, the city could move all the homes and businesses near the coast inland. Development would need to relocate roughly three blocks inland to sustain a six-and-a-half foot sea level rise. The city would then have to densify inland and rebuild buildings, roads and other infrastructure that’s now on the coast.
That’s tough to swallow. But, Dedina said, the city can make easier decisions for now.
Bayside Elementary School, for instance, is not far above sea level and would be constantly flooded and under water if sea levels rise six-and-a-half feet.
“Eventually we’ll have to have the conversation of whether the school is going to have a playground or a salt marsh,” Dedina said.
A storm drainage basin is below the school and just a few feet above sea level. The city can relocate the basin to a higher elevation, or re-engineer it to handle bigger storm surges.
With more than six feet sea-level rise, a majority of IB’s drainage basins would be flooded more than 90 percent of the time.
The city can fix that and other stormwater infrastructure to improve its situation.
Those are the small, tangible things that they’ll have to start with, Dedina said.
That’s why Dedina says he ferociously supports a proposed SANDAG ballot measure that would tax county residents to fund transportation projects. The funding his city would get from it could fund improvements to stormwater drainage basins.
In June, the Imperial Beach sea-level rise steering committee met at the Tijuana Estuary Visitor’s center. The group of leaders from the Port of San Diego, environmental groups, city staff and politicians from Imperial Beach and other researchers have been meeting for months, as Revell’s consulting group moved forward with its study.
One of the committee’s members, Imperial City Councilman Ed Spriggs walked in, having just returned home from a trip to New York City.
They’ve got some sea-level rise problems there, commented some of his fellow committee members, making small talk before the meeting started.
”Yeah, they’ve got problems there,” Spriggs said. “They’ve got money, though.”
Imperial Beach doesn’t.
The city used grant money from the California State Coastal Conservancy and from the San Diego Foundation to hire Revell’s team. It’s also applied for a grant from the Coastal Commission just to update coastal zoning so it can build and fix infrastructure projects that would protect the coastline.
The city is trying its best to be resourceful.
If it gets some of its most vulnerable areas on FEMA hazard maps, then the federal government will help pay for repairs and rebuilding if there are damages after a storm.
The city is also ensuring new development is prepared for the next 100 years. The Bernardo Shores project, in one of the lower-income areas of IB, will be built behind the 100-year flood line and contain bioswales – a drainage course with slightly sloped sides, filled with vegetation to absorb and carry away stormwater runoff.
Pond 20 on Port of San Diego land, is another opportunity.
The Port is restoring part of the property as wetlands. Developers trying to offset the environmental impact of projects will be able to purchase that land.
Once the Port makes back the money it spent restoring those wetlands, remaining profit from developers will go to Imperial Beach and other communities for reinvestment.
“Imperial Beach has done more per person to preserve open space than anywhere in the county,” Dedina said. “We’ve got to be compensated for that and Pond 20 is an attempt to do that.”
That money, in some way, can be used for adaption, Dedina said.
Some wealthier communities like Malibu have created special geological hazard districts to levy taxes on residents and use the money to protect eroding coastlines. That’s not a great option in Imperial Beach, where the average income is barely $50,000.
At a May public workshop on sea level rise, Dani Boudreau, who works on climate issues for the Tijuana River National Estuarine Research Reserve, told Imperial Beach residents that though things seemed grave, there were things they could do.
She ran through the state and non-state grants that had been given to other cities, highlighting that Imperial Beach could vie for some and could learn from other cities, SDG&E and the Port of San Diego.
“Often we think of sea-level rise as a global issue,” Boudreau said. “But this is a local issue. We will be dealing with this issue as a local community. This is something we are going to have to lead as residents, as local business owners, as homeowners. This is something that is going to come home to us.”