Southern California coastline health
Two things you can see from a boat: the kelp, and the sand. Kelp canopy since the 2014 heatwave has averaged — less than the 30 years before. On the beaches, each decade since the 1980s has placed less sand. And in the water, rain explains much of the bad bacteria counts, except at the beaches near the Tijuana River, where most samples fail in any season. And where the same beach was refilled more than once, each cubic yard has cost more.
The kelp layer
Kelp canopy, Point Conception to the Mexico border
Satellite-measured canopy area, the largest quarter each year, including the Channel Islands. Shaded bands are strong El Niños and the 2014–16 marine heatwave.
Kelp canopy by region
The same satellite record split into seven stretches of coast. Each chart has its own scale; the figure on the right is the 2014–2025 average against 1984–2013. Shaded years are El Niños and the 2014–16 heatwave.
Scripps Pier water temperature
Each bar is a year's mean surface temperature against the 1916–2024 average (17.25 °C). Daily readings from the pier since 1916; years count only when all 12 months have readings.
Sea level at La Jolla and Los Angeles
Annual mean sea level, in centimeters relative to 1983–2001. La Jolla's record starts in 1925.
Warming at every pier, not just Scripps
Each station's average for 2014–2025 minus its own 1960–1979 average, from the same Shore Stations program. Stations with fewer than three years in either period are left off.
Urchins and kelp on Channel Islands reefs, 1983–2007
Diver counts at the same 14 Park Service sites every year. Purple urchins per square meter (bars) against adult giant kelp plants (line). The public series ends in 2007.
Sunflower sea star sightings, California to Alaska
Public iNaturalist sightings (research grade, openly licensed copies via GBIF) per year. The number on the right is sightings per 1,000 sea star sightings of any kind in 2024–2026, which corrects for far more people using the app. Each chart has its own scale.
The sunflower star's last decade
Outbreak, listings, captive breeding and the first sightings back, each from a dated source.
What the commercial fleet brings in
Pounds landed statewide each year (NOAA Fisheries for lobster, sardine, squid and anchovy through 2024; state records for red urchin). Each chart has its own scale. The dashed line marks the 2014–16 heatwave; sardine fishing has been closed since 2015.
The water we swim in
How much of bad beach water is just rain?
Share of bacteria samples over the state limit, by how rainy the month was, 2004–2025. San Diego is split into the beaches near the Tijuana River (Imperial Beach to Coronado) and everything else.
Beach closure days per year
Each beach closed for a day counts as one closure day. 2000 has no closure records in the state database, so it's left blank.
The sand layer
Sand placed on beaches, by decade
Recorded nourishment projects in Los Angeles, Orange and San Diego counties. Early decades include large harbor and construction fills.
What a cubic yard of sand costs
Each dot is a project that reported both cost and volume (nominal dollars, log scale). The line connects refills of the same beach, Surfside–Sunset in Orange County.
San Diego beach width, fall surveys
Average width at mean sea level for monitoring sites surveyed every fall from 1997 to 2024, by littoral cell. The jumps after 2001, 2012 and 2024 line up with the big regional sand projects, so a flat line here means sand is being added to keep it flat.
How much of the coast is walled off
Share of each county's open coast behind seawalls, revetments or riprap. Across Ventura, Los Angeles, Orange and San Diego counties, armoring went from — of the shoreline in 1971 to — in 2018. Most of it was built before 1998; the last two decades added about — miles. The 1971 figures come from an Army Corps survey and later years from aerial photos, so part of the early jump may be better mapping. Harbors and bays aren't counted.
Where the walls are
Each dot is about half a kilometer of coast; bigger dots mean more of that stretch is armored. Together they add up to — miles across the five counties, including Santa Barbara. From the state's coastal armoring inventory, mapped mostly from 2004–05 aerial photos with a few 2012–13 updates. It shows where the walls are, not how they've changed.
Walled beaches are narrower, and sand is what's holding them
San Diego beach-width transects, split by whether they got sand in the 2001 and 2012 regional projects and whether at least half of the half-kilometer around them is armored. Walled beaches are narrower in every group, but over these years they haven't shrunk faster. — of the — heavily walled sites were sand receivers. Most walls predate the record, the groups are small, and walls may have been built where beaches were already narrow, so this shows a pattern, not a cause.
| Group | Sites | Median width, 1997–2001 | Median width, 2020–24 | Median change |
|---|
Sand promises
Public commitments to put sand on Southern California beaches, fund it, or pull back from the shore, and what happened. Of — tracked, — were delivered and — were not. — are standing refill schedules, like every five years for 50 years, and we found no funding committed for any of their next cycles. The clock below covers the one-time commitments still open, measured from the day each was made.
| Who | Commitment | By when | Status |
|---|
Who pays for the sand
Sand placed on Southern California beaches since 1990, by who paid for it, as a share of cubic yards. Projects with state money in them, through grants that cover most of a city's share, placed — of the sand in the 2000s, — in the 2010s and — so far in the 2020s. That state fund now has no dedicated revenue source, and its 2026–27 round is about $1.5 million statewide, compared with an $11.5 million grant to Encinitas–Solana Beach alone. Shares are by volume, not dollars. Many records name only the lead funder, so "Federal" projects usually had a local share too.
The train on the bluffs
The coastal rail line between San Diego and Los Angeles runs along eroding bluffs and beaches. Since 2018 we found — erosion or landslide closures with — days of documented shutdown, — of them in San Clemente. Each bar is a closure; same-day stoppages show as thin marks. Hundreds of millions have gone to holding the line in place. Moving it, through a Del Mar tunnel by 2035 or inland in south Orange County, has no construction funding, and the state says no decision has been made to relocate in San Clemente.
| Who | Commitment | By when | Status |
|---|
Who has decided when to move back
Coastal scientist Gary Griggs argues every community needs agreed triggers for adapting or moving back, such as a sea level reached, a number of floods, or a bluff edge a set distance from a home. Of the — Southern California cities and counties we checked, — have measurable triggers tied to actions, — mention triggers without numbers, and — have none we could find. — (Del Mar and Imperial Beach) dropped managed retreat from their plans. "None found" means we searched the published plans and found none, which isn't proof that none exist.
| Where | Measurable triggers | What the plan says |
|---|
How fast the cliffs retreat
Published measurements use different methods and periods, so they're shown side by side, not as a trend.
| Where | From | To | Rate | Unit |
|---|
Bluff failures
Dated collapses and the rail closures they caused.
Corrections and changes
When something on this page turns out to be wrong or incomplete, the fix is logged here with the date and the reason. Last change: —.
How this was built
Kelp canopy is Kelpwatch's Landsat series for Southern California; the regional split comes from the SBC LTER California kelp canopy and environment file (Bell, 2026, CC BY 4.0), totaled per region from its 30 m pixels using each year's largest quarter. Satellite pixels miss narrow fringing beds, so small island totals like Catalina's run low. Water temperature is the Scripps Shore Stations daily pier record (archive of Sept 30, 2026), averaged by month and then by year using only readings flagged good, and sea level from NOAA tide gauges. Beach widths are SANDAG's Regional Beach Monitoring Program fall surveys, limited to sites surveyed every year so the average compares the same places. Nourishment projects combine SANDAG's reports for San Diego County (1994 on) with the Western Carolina University beach nourishment database for the rest.
Costs are as reported, in the year's dollars, and most projects never reported one. Projects under 10,000 cubic yards are left off the cost chart. Reef surveys are the Channel Islands National Park Kelp Forest Monitoring 1 m quadrats served by NOAA ERDDAP, averaged over the 14 sites surveyed every year from 1983 to 2007; the Park Service's full 1982–2025 package is marked controlled and wasn't used. Sunflower star sightings are iNaturalist research-grade records as published on GBIF (openly licensed ones only, so they undercount iNaturalist); iNaturalist blurs the location of threatened species, so a few records near a region's edge may fall in the neighboring region. Commercial landings come from NOAA Fisheries' FOSS database (PacFIN data) and CDFW landings tables; dollar values are dock prices in that year's dollars. Beach water is every bacteria sample in the State Water Board's beach database for LA, Orange and San Diego counties, 1999–2025, with rainfall from NOAA stations at downtown LA, John Wayne Airport and Lindbergh Field; rain advisories are left out because they're issued before any sample is taken, and some San Diego beaches switched to a DNA-based test in 2022. Pier temperatures for the other stations come from the same Shore Stations archive, averaged the same way as Scripps. Nothing here is estimated: missing values stay missing.