San Diego County’s seashores want pricey, sustained replenishment efforts to stay the extensive, sandy vacationer points of interest they’ve been for thus lengthy, a brand new regional examine exhibits.
Shorelines in south Oceanside, south Carlsbad, Leucadia and Coronado are shrinking quick, in line with the 2023 “State of the Coast” report launched Thursday by the San Diego Affiliation of Governments.
Solely seashores bolstered by sand dredged from close by lagoons, harbors and offshore deposits are sustaining their width or rising, says the report, offered Thursday at a gathering of SANDAG’s Shoreline Preservation Working Group.
Most California seashores have by no means been the extensive, sandy expanses seen in East Coast states comparable to Florida, some specialists say. Many of the West Coast shore is steep, rocky and pounded by highly effective waves, and the seaside tradition popularized by motion pictures and promoting is essentially a fable.
“Seashores are the essence of California and supply its most necessary aesthetic and leisure asset,” oceanographer Reinhard Flick of Scripps Establishment of Oceanography wrote in 1993 in his paper known as “The Delusion and Actuality of Southern California Seashores.”
“But the widest sand seashores in Southern California have been created and are maintained by human exercise,” stated Flick, who at present is an advisory member of the SANDAG working group.
Individuals have dumped large quantities of sand alongside the coast through the years and constructed groins, jetties and breakwaters to maintain it there.
The California Coastal Fee, established by voters in 1972, discourages the development of groins and different laborious retention units alongside the coast as a result of, whereas they might maintain sand in a single spot, they contribute to erosion elsewhere. However the fee continues to advertise and generally requires sand placement tasks.
Human exercise is also a think about seaside losses. Upstream growth from river dams to parking tons stops the downstream circulate of sediment. Coastal development, comparable to properties and highways, prevents the pure erosion of cliffs and bluffs that contributes to seaside progress.
SANDAG has led two regional tasks that positioned sand on a number of places alongside the county’s coast. These efforts had been 11 years aside, and the newest was greater than a decade in the past.
“After every of the regional seaside tasks we had beneficial properties, however they’re solely sustained for a pair years,” stated stated Greg Hearon of the environmental consulting agency Coastal Frontiers, who helped put together the SANDAG report.
The primary challenge, accomplished in 2001, positioned 2.2 million cubic yards of sand, primarily from the San Diego harbor, on seashores the size of the county. It price $18 million, of which 60 % was funded by federal grants and 40 % by state grants.
A second regional effort, accomplished in 2012, positioned 1.4 million cubic yards of sand pumped from offshore deposits on seashores at a value of $26 million. The state paid for 85 % of that challenge, with the native jurisdictions contributing 15 %.
SANDAG just lately started research for a proposed third regional challenge, which is a number of years away and will price near $40 million.
Smaller-scale tasks have benefited seashores in a number of locations alongside the county’s coast, however the beneficial properties may be fleeting.
Seashores in Oceanside, south Carlsbad, Leucadia and Coronado misplaced a mean of two ft or extra in width yearly over the previous 22 years, a brand new report exhibits.
Oceanside’s harbor entrance is dredged yearly for navigation by the U.S. Military Corps of Engineers, which offers sand to keep up town seaside nearest the harbor. Nonetheless, the sediment is fine-grained and washes away shortly, and there’s not sufficient to unfold very far south.
Northern Carlsbad seashores get sand from the occasional dredging of Agua Hedionda Lagoon, which for years was saved open by San Diego Fuel & Electrical Co. to supply cooling water for the Encina energy plant. Now the operators of the Carlsbad desalination plant dredge the lagoon.
Carlsbad has virtually 7 miles of shoreline, although, and seashores on the southern finish, within the Ponto space, are struggling. The common width there may be 88 ft, which is worrisome, Hearon stated.
Winter storms erode Southern California seashores, whereas the regular waves and long-shore currents of summer time assist to revive the sand and construct them again up.
“South Carlsbad simply appears to be one (place) that doesn’t cling onto something,” Hearon stated. “Going right into a winter with a seaside lower than 100 ft ought to get your consideration.”
Encinitas and Solana Seaside bought an enormous dose of sand from the restoration of the San Elijo Lagoon in 2018. Excavated materials was used to create the county’s first “dwelling shoreline” dune system on the close by seaside.
The experimental program added 8 acres of dunes masking a base of rock riprap and cobble, and planted with native vegetation for stability. Consequently, the seaside at Cardiff in southern Encinitas added 4.5 ft in width, and Solana Seaside, instantly to the south, added 5 ft.
Encinitas and Solana Seaside are also set to get sand from a brand new seaside nourishment effort starting this fall known as the Military Corps of Engineers’ Coastal Storm Harm Discount Challenge.
In growth since 2000, it’s supposed to proceed periodic replenishment efforts in these two cities for the subsequent 50 years. In 2015, the price over the lifetime of the challenge was estimated at $167 million. Final yr federal officers allotted $32 million for the primary part of labor.
Nonetheless, many San Diego County seashores proceed to erode.
Oceanside’s shoreline misplaced a mean of two.3 ft in width at imply sea degree annually from fall 2020 by fall 2022, in line with the report.
At its finest, Oceanside has 205 ft of seaside at Windward Approach close to the harbor. The width shrinks shortly south of town’s pier to only 18 ft at Buccaneer Seaside and 15 ft at St. Malo. At excessive tide, the surf crashes on rock revetments defending seaside properties in most of south Oceanside.
Coronado’s Silver Strand misplaced probably the most width of all, a mean of three.8 ft per yr. Nonetheless, Coronado has sand to spare, and nonetheless measured 686 ft extensive in 2022.
Different seashores monitored for the report remained comparatively steady or had barely growing quantities of sand.
Some folks instructed extra knowledge factors be included within the shoreline monitoring challenge, which incorporates little info from the shoreline alongside town of San Diego.
“There’s numerous erosion in Tourmaline (close to Mission Bay) and Level Loma, however you guys don’t gather info there,” stated Katheryn Rhodes. “These are actually necessary areas that want monitoring.”
SANDAG plans to broaden this system by permitting the general public to go surfing and contribute their very own images and observations to the database.
Flick, the oceanographer, stated local weather change will increase the significance of monitoring seaside erosion.
“It’s going to get extra essential as sea-level rise accelerates,” Flick stated.
This story initially appeared in San Diego Union-Tribune.
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