FIELD NOTE · SUPPLEMENTAL SET
Concrete poured to a permit year: Balboa Island bulkheads and an elevation that steps without them
ISSUEDJULY 11, 2026DRAWN BY THE NIGHTLY SWEEP
A bulkhead cap on Balboa Island reads as one continuous line of poured concrete, and it is not one structure. The bulkheads here are, in a condition report reproduced in a December 2024 California Coastal Commission staff report, "maintained individually by property owners, but function as a uniform structure to protect more than just the individual properties." The line is a row of separate specification decisions, each fixed by the year its permit issued rather than by any water level.
Newport Beach prints those years in a table, the Harbor Design Criteria, revised January 25, 2022 and readable now only in an April 2025 capture of the City's own file. It sets the adopted standard elevation at 10.7 feet NAVD88 for a seawall permitted in 2020, 10.9 feet for 2021 through 2025, and 11.0 feet for 2026 through 2030. A second column, the design for adaptability elevation, runs 13.7 feet, then 14.4, then 14.6, with a fourth row already written for 2031 through 2035 at 11.0 and 14.8. The 2021 through 2025 row expired on December 31, 2025, the 11.0 foot row took effect on January 1, 2026, and nothing standing today was poured to a row that does not open until 2031, so three requirements have ever been in force and a fourth is already waiting.
A wall is poured once.
So the number a wall is formed to is a percentile, projected 75 years out, for a gauge in Los Angeles.
The guidance underneath it has since been replaced. On June 4, 2024 the California Ocean Protection Council adopted a Science and Policy Update that "updates and replaces the previous 2018 State of California Sea-Level Rise Guidance." It retired the risk-aversion vocabulary those footnotes are written in. The copy captured in April 2025 still says that "currently the best available science is the State of California Sea Level Rise Guidance, 2018 Update."
The table converts inconsistently as well. Three of its four rows separate NAVD88 from MLLW by 0.2 feet, where the row now in force prints 11.0 feet NAVD88 against 11.1 feet MLLW. A tenth of a foot, in the governing document, is a clerical question right up until the forms go up. The wall that reads correct in one column reads short in the other, and after the pour the only corrections left are the two the City later bought on its own wall: a cap, or a replacement.
That removal was a decision somebody made in a budget year, and it is why a bulkhead on Balboa Island is now formed off a gauge in another county. There is no active NOAA gauge in Newport Harbor, and what NOAA publishes for Newport now is prediction, controlled by the Los Angeles station.
For a measured trend the nearest long record is Los Angeles, station 9410660, where relative sea level has risen 1.07 millimeters a year, plus or minus 0.20, from 1923 to 2025, which is about four inches a century. Annual maximum water level there has meanwhile gone nowhere in particular, sitting inside a band from 6.81 to 7.72 feet across the whole record from 1983 to 2026.
The projections are a different quantity, and they are the quantity the table is made of. The Ocean Protection Council's 2024 update publishes medians for the Los Angeles gauge above a 2000 baseline: under Intermediate-High, 0.9 feet by 2050, 3.6 feet by 2090 and 4.5 feet by 2100, and 2.8 feet by 2100 under Intermediate. Added to the 7.49 foot record extreme those become 8.4, 11.1 and 12.0 feet NAVD88, and 10.3 feet under Intermediate. That is arithmetic on published figures rather than a forecast, and it double counts a little, since the medians are referenced to 2000 and the observation is from 1983.
The City's answer was nine inches of concrete. On August 8, 2017 the Council voted 6-0, with one member recused for a real property interest, to cap the existing seawall on the north, south and west sides of the island, against an engineer's estimate of $1.5 to $2 million. The same reporting gave the alternative as replacement with 10-foot walls extensible to 14 feet, estimated at $68 million, so nine inches was a financing decision, and what the estimate bought was nine inches.
WHAT SET THE ELEVATION January 28 1983 Highest water level ever measured at the harbor entrance, 7.49 feet NAVD88 January 27 1994 NOAA removes station 9410580 and the harbor loses its gauge October 10 2014 The island's perimeter wall is reported at 7.9 to 9.3 feet MLLW August 8 2017 Council votes 6-0, one member recused, to cap the seawall on three sides June 4 2024 The Ocean Protection Council replaces the 2018 guidance the table rests on January 1 2026 The required crest steps to 11.0 feet NAVD88, adaptability to 14.6
In December 2024 Coastal Commission staff recommended approval of CDP 5-24-0348, a 2-foot-2-inch stem wall on an existing bulkhead coping. The report finds that "No bayward encroachment of the existing bulkhead is proposed or will occur," and that the finished height "will be 10.90 feet NAVD88/11.1 feet MLLW." The same staff report twice gives that finished height as 10.11 feet NAVD88 instead, roughly nine and a half inches lower, so the record disagrees with itself by nearly eight times the step between two rows of the table. The applicant's consultant stated the cap could later be raised to 14.4 feet NAVD88 without extending the bayward footprint. That is the one elevation in the file nothing contradicts, and it belongs to a row that closed on December 31, 2025.
None of this work reaches the record as a seawall permit. It arrives as a Coastal Development Permit, decided by the City's Zoning Administrator under the certified Local Coastal Program, or by the Coastal Commission where the bulkhead sits in the Commission's own original jurisdiction, as it did in CDP 5-24-0348. Either way the crest and adaptability elevations end up written into a condition of approval, which is where a contractor reading the Newport Beach record finds the elevation before anybody orders concrete. Filings scored nightly for waterproofing contractors put that condition in front of the trade while the crest is still a line on a drawing.
The wall that ends up low will not have failed. It will have been built exactly to the row that was open the month its owner applied, and left standing beside a neighbor's wall poured a tenth of a foot higher under the next row.
The decision the entire line is made of is a filing date. A bulkhead permitted this month is built to 11.0 feet NAVD88 and detailed to reach 14.6, as the criteria read in the last copy the City has served. Table No. 2 has no row after 2035.
Newport Beach prints those years in a table, the Harbor Design Criteria, revised January 25, 2022 and readable now only in an April 2025 capture of the City's own file. It sets the adopted standard elevation at 10.7 feet NAVD88 for a seawall permitted in 2020, 10.9 feet for 2021 through 2025, and 11.0 feet for 2026 through 2030. A second column, the design for adaptability elevation, runs 13.7 feet, then 14.4, then 14.6, with a fourth row already written for 2031 through 2035 at 11.0 and 14.8. The 2021 through 2025 row expired on December 31, 2025, the 11.0 foot row took effect on January 1, 2026, and nothing standing today was poured to a row that does not open until 2031, so three requirements have ever been in force and a fourth is already waiting.
A wall is poured once.
Concrete poured to whichever row was open
Both columns are derived rather than measured, and the whole derivation sits in two footnotes. Footnote 1 takes the standard elevation from "the Upper Limit of the Low Risk Aversion probabilistic sea level rise protection scenario for the Los Angeles tidal gauge," estimated 75 years into the future under the State of California Sea Level Rise Guidance, 2018 Update, which is approximately an 83 percent probability that sea level rise falls below the elevations shown. Footnote 2 takes the adaptability elevation from the Medium-High Risk Aversion scenario, at approximately a 1-in-200, or 0.5 percent, probability of being exceeded.So the number a wall is formed to is a percentile, projected 75 years out, for a gauge in Los Angeles.
The guidance underneath it has since been replaced. On June 4, 2024 the California Ocean Protection Council adopted a Science and Policy Update that "updates and replaces the previous 2018 State of California Sea-Level Rise Guidance." It retired the risk-aversion vocabulary those footnotes are written in. The copy captured in April 2025 still says that "currently the best available science is the State of California Sea Level Rise Guidance, 2018 Update."
The table converts inconsistently as well. Three of its four rows separate NAVD88 from MLLW by 0.2 feet, where the row now in force prints 11.0 feet NAVD88 against 11.1 feet MLLW. A tenth of a foot, in the governing document, is a clerical question right up until the forms go up. The wall that reads correct in one column reads short in the other, and after the pour the only corrections left are the two the City later bought on its own wall: a cap, or a replacement.
Mean higher high water at 5.23 feet, and a gauge removed in 1994
Against a schedule that precise, the water itself turns out to be documented badly. NOAA removed station 9410580, Newport Bay Entrance, on January 27, 1994, so the datums everybody quotes come from a fourteen-year series that ended in December 1993, on the 1983 through 2001 tidal epoch. Mean higher high water there is 5.23 feet NAVD88, and the highest water level ever measured at the station was 7.49 feet NAVD88 on January 28, 1983.That removal was a decision somebody made in a budget year, and it is why a bulkhead on Balboa Island is now formed off a gauge in another county. There is no active NOAA gauge in Newport Harbor, and what NOAA publishes for Newport now is prediction, controlled by the Los Angeles station.
For a measured trend the nearest long record is Los Angeles, station 9410660, where relative sea level has risen 1.07 millimeters a year, plus or minus 0.20, from 1923 to 2025, which is about four inches a century. Annual maximum water level there has meanwhile gone nowhere in particular, sitting inside a band from 6.81 to 7.72 feet across the whole record from 1983 to 2026.
The projections are a different quantity, and they are the quantity the table is made of. The Ocean Protection Council's 2024 update publishes medians for the Los Angeles gauge above a 2000 baseline: under Intermediate-High, 0.9 feet by 2050, 3.6 feet by 2090 and 4.5 feet by 2100, and 2.8 feet by 2100 under Intermediate. Added to the 7.49 foot record extreme those become 8.4, 11.1 and 12.0 feet NAVD88, and 10.3 feet under Intermediate. That is arithmetic on published figures rather than a forecast, and it double counts a little, since the medians are referenced to 2000 and the observation is from 1983.
A nine-inch cap on a ninety-year wall
The island's own perimeter wall is a different structure from the private bulkheads, and much older. The seawalls circling the 1.7-mile perimeter were described in August 2017 reporting as nearly 80 to 90 years old, which makes them roughly 90 to 100 now. On October 10, 2014 the Newport Beach Independent reported them varying in height "from between 7.9 feet and 9.3 feet at Mean Lower Low Water," or roughly 7.7 to 9.1 feet NAVD88 on NOAA's 0.18 foot separation. The 7.49 feet NAVD88 measured on January 28, 1983 sits about two and a half inches under the low end of that band, which is the margin the island holds at its lowest section against the highest water the harbor has recorded.The City's answer was nine inches of concrete. On August 8, 2017 the Council voted 6-0, with one member recused for a real property interest, to cap the existing seawall on the north, south and west sides of the island, against an engineer's estimate of $1.5 to $2 million. The same reporting gave the alternative as replacement with 10-foot walls extensible to 14 feet, estimated at $68 million, so nine inches was a financing decision, and what the estimate bought was nine inches.
WHAT SET THE ELEVATION January 28 1983 Highest water level ever measured at the harbor entrance, 7.49 feet NAVD88 January 27 1994 NOAA removes station 9410580 and the harbor loses its gauge October 10 2014 The island's perimeter wall is reported at 7.9 to 9.3 feet MLLW August 8 2017 Council votes 6-0, one member recused, to cap the seawall on three sides June 4 2024 The Ocean Protection Council replaces the 2018 guidance the table rests on January 1 2026 The required crest steps to 11.0 feet NAVD88, adaptability to 14.6
A cap that has to rise without moving bayward
The adaptability column is a construction requirement, not advice. The criteria require that the structure "shall also be initially designed and constructed to accommodate and receive future increases in height when directed by the City to protect adjacent low-lying areas from future flooding without the need to replace or substantially alter the structure." That puts two elevations into one pour, the 11.0 feet the wall is built to and the 14.6 feet it has to be able to reach.In December 2024 Coastal Commission staff recommended approval of CDP 5-24-0348, a 2-foot-2-inch stem wall on an existing bulkhead coping. The report finds that "No bayward encroachment of the existing bulkhead is proposed or will occur," and that the finished height "will be 10.90 feet NAVD88/11.1 feet MLLW." The same staff report twice gives that finished height as 10.11 feet NAVD88 instead, roughly nine and a half inches lower, so the record disagrees with itself by nearly eight times the step between two rows of the table. The applicant's consultant stated the cap could later be raised to 14.4 feet NAVD88 without extending the bayward footprint. That is the one elevation in the file nothing contradicts, and it belongs to a row that closed on December 31, 2025.
None of this work reaches the record as a seawall permit. It arrives as a Coastal Development Permit, decided by the City's Zoning Administrator under the certified Local Coastal Program, or by the Coastal Commission where the bulkhead sits in the Commission's own original jurisdiction, as it did in CDP 5-24-0348. Either way the crest and adaptability elevations end up written into a condition of approval, which is where a contractor reading the Newport Beach record finds the elevation before anybody orders concrete. Filings scored nightly for waterproofing contractors put that condition in front of the trade while the crest is still a line on a drawing.
The wall that ends up low will not have failed. It will have been built exactly to the row that was open the month its owner applied, and left standing beside a neighbor's wall poured a tenth of a foot higher under the next row.
The decision the entire line is made of is a filing date. A bulkhead permitted this month is built to 11.0 feet NAVD88 and detailed to reach 14.6, as the criteria read in the last copy the City has served. Table No. 2 has no row after 2035.