Stabilize Kingsley Plantation seawall against erosion
Stabilize Kingsley Plantation Seawall
National Park Service· Timucuan Ecological and Historic Preserve, Kingsley PlantationNPS Planning (PEPC) project page ↗
NPS PEPCWe track this on the agency’s own system of record, where most on-the-ground decisions live.
A historic Florida plantation site faces permanent loss to shoreline erosion without this repair.
What’s at risk
Kingsley Plantation, a culturally significant historic site within Timucuan Ecological and Historic Preserve, is threatened by ongoing shoreline erosion and flooding. Without stabilization, the seawall and the history it protects could be lost.
If we stay silent
The National Park Service would stabilize and extend the seawall, giving the site lasting protection from erosion and flood damage.
Our plain-English read of the official notice ↗. Check it against the agency’s own words below.
6 holes in the agency’s own analysis
What the public could have raised, from the agency’s own document
- I support this action and urge the agency to advance it.
- The document openly states the CISA regulatory flood elevation is +11 ft NAVD88 but then acknowledges the new seawall will only reach +8.5 ft NAVD88, a 2.5-foot shortfall below the agency's own computed standard. Section 3.2 dismisses this gap by saying the primary concern is shoreline stabilization and viewshed preservation, but no engineering analysis, cost-benefit comparison, or regulatory waiver is cited to justify building 2.5 feet below the flood standard the agency calculated. The agency should either justify in writing why constructing below the CISA elevation is acceptable under PM 77-2 and 520 DM 2, or redesign the wall to meet the standard it computed.
- The document rounds the NOAA intermediate SLR projection of 1.44 ft up to 2 ft when computing the CISA regulatory elevation, inflating the stated standard from roughly +10.44 ft to +11 ft NAVD88. Yet the new seawall is set at +8.5 ft, meaning even using the unrounded 1.44 ft figure the wall would still fall roughly 1.94 feet short of the unadjusted CISA level. The document provides no explanation for why rounding is methodologically appropriate or how the rounded figure was derived under the cited NOAA or FFRMS guidance. The agency should disclose the exact rounding rule applied and show whether any recognized FFRMS methodology authorizes it.
- Section 3.2 states that site-specific sediment modeling confirmed no measurable downstream shoreline impact, yet no details of that model are provided anywhere in the document: no model name, no input parameters, no output data, no uncertainty range, and no citation. The document repeats this claim twice but treats it as self-validating. Because the extension wall will be placed above the MHW line along an eroding bluff, sediment dynamics downstream are a genuine concern. The agency should release the full sediment modeling report as part of the public record so the claim can be evaluated.
- The document states the existing wall was overtopped as recently as 2022 when storm surge reached approximately +6.6 ft NAVD88 SWEL against a wall top of +7 ft NAVD88. The new wall will be +8.5 ft NAVD88, yet Section 3.1 acknowledges that during a 100-year storm surge alone reaches +6.6 ft NAVD88 before wave action is added, and that the CISA standard is +11 ft. No wave-runup analysis is presented to show whether +8.5 ft is sufficient to prevent overtopping under the design storm. The agency should provide or cite a wave-runup calculation demonstrating whether the proposed wall height offers meaningful improvement over the existing wall during the design storm.
Show all 8 points from the document
- The document says the aquatic resource delineation was conducted in December 2025 and identifies permanent loss of 0.018 acre of intertidal waters and conversion of 0.049 acre of unconsolidated shore. However, no assessment of impacts to oyster habitat, juvenile fish habitat, or shorebird foraging beyond the delineated footprint is provided. Section 3.2 mentions that tidal flats provide habitat for oysters and juvenile marine life but then states construction will not encroach on delineated wetlands without addressing whether riprap placement and pile hammering create indirect impacts beyond the delineated boundary. The agency should provide an analysis of indirect and cumulative impacts to aquatic resources within the project influence area, not just within the delineated footprint.
- The document adopts a 35-year design life correlating to 2060 and uses the NOAA intermediate SLR scenario of 1.44 ft for that period. However, NOAA's Sea Level Rise Viewer also provides higher scenarios, and the document does not explain why the intermediate scenario is selected over a higher scenario for a coastal structure protecting irreplaceable archaeological resources. The document itself acknowledges that complete avoidance of storm-driven flood risk is unlikely and that the wall will not prevent overtopping during a 100-year storm. Using a more conservative SLR scenario could change both the CISA elevation and the adequacy of the proposed wall height. The agency should disclose why the intermediate rather than the intermediate-high or high scenario is used to size a structure protecting non-replaceable cultural resources.
- Say something only you can say. The law requires the agency to consider and respond to substantive comments, and specifics are what make a comment substantive.
In the agency’s own words
Kingsley Plantation Seawall and Shoreline Extension Floodplain Statement of Findings
Did the agency answer?
6 issues are on this record. The agency has not published its decision document yet, so each one stays pending until the agency answers.
Issues on the record, awaiting the decision
- PendingThe document openly states the CISA regulatory flood elevation is +11 ft NAVD88 but then acknowledges the new seawall will only reach +8.5 ft NAVD88, a 2.5-foot shortfall below the agency's own comput
The document openly states the CISA regulatory flood elevation is +11 ft NAVD88 but then acknowledges the new seawall will only reach +8.5 ft NAVD88, a 2.5-foot shortfall below the agency's own computed standard. Section 3.2 dismisses this gap by saying the primary concern is shoreline stabilization and viewshed preservation, but no engineering analysis, cost-benefit comparison, or regulatory waiver is cited to justify building 2.5 feet below the flood standard the agency calculated. The agency should either justify in writing why constructing below the CISA elevation is acceptable under PM 77-2 and 520 DM 2, or redesign the wall to meet the standard it computed.
A hole PLAN found in the agency’s own analysis, quote verified against the document
- PendingThe document rounds the NOAA intermediate SLR projection of 1.44 ft up to 2 ft when computing the CISA regulatory elevation, inflating the stated standard from roughly +10.44 ft to +11 ft NAVD88.
The document rounds the NOAA intermediate SLR projection of 1.44 ft up to 2 ft when computing the CISA regulatory elevation, inflating the stated standard from roughly +10.44 ft to +11 ft NAVD88. Yet the new seawall is set at +8.5 ft, meaning even using the unrounded 1.44 ft figure the wall would still fall roughly 1.94 feet short of the unadjusted CISA level. The document provides no explanation for why rounding is methodologically appropriate or how the rounded figure was derived under the cited NOAA or FFRMS guidance. The agency should disclose the exact rounding rule applied and show whether any recognized FFRMS methodology authorizes it.
A hole PLAN found in the agency’s own analysis, quote verified against the document
- PendingSection 3.2 states that site-specific sediment modeling confirmed no measurable downstream shoreline impact, yet no details of that model are provided anywhere in the document: no model name, no input
Section 3.2 states that site-specific sediment modeling confirmed no measurable downstream shoreline impact, yet no details of that model are provided anywhere in the document: no model name, no input parameters, no output data, no uncertainty range, and no citation. The document repeats this claim twice but treats it as self-validating. Because the extension wall will be placed above the MHW line along an eroding bluff, sediment dynamics downstream are a genuine concern. The agency should release the full sediment modeling report as part of the public record so the claim can be evaluated.
A hole PLAN found in the agency’s own analysis, quote verified against the document
- PendingThe document states the existing wall was overtopped as recently as 2022 when storm surge reached approximately +6.6 ft NAVD88 SWEL against a wall top of +7 ft NAVD88.
The document states the existing wall was overtopped as recently as 2022 when storm surge reached approximately +6.6 ft NAVD88 SWEL against a wall top of +7 ft NAVD88. The new wall will be +8.5 ft NAVD88, yet Section 3.1 acknowledges that during a 100-year storm surge alone reaches +6.6 ft NAVD88 before wave action is added, and that the CISA standard is +11 ft. No wave-runup analysis is presented to show whether +8.5 ft is sufficient to prevent overtopping under the design storm. The agency should provide or cite a wave-runup calculation demonstrating whether the proposed wall height offers meaningful improvement over the existing wall during the design storm.
A hole PLAN found in the agency’s own analysis, quote verified against the document
- PendingThe document says the aquatic resource delineation was conducted in December 2025 and identifies permanent loss of 0.018 acre of intertidal waters and conversion of 0.049 acre of unconsolidated shore.
The document says the aquatic resource delineation was conducted in December 2025 and identifies permanent loss of 0.018 acre of intertidal waters and conversion of 0.049 acre of unconsolidated shore. However, no assessment of impacts to oyster habitat, juvenile fish habitat, or shorebird foraging beyond the delineated footprint is provided. Section 3.2 mentions that tidal flats provide habitat for oysters and juvenile marine life but then states construction will not encroach on delineated wetlands without addressing whether riprap placement and pile hammering create indirect impacts beyond the delineated boundary. The agency should provide an analysis of indirect and cumulative impacts to aquatic resources within the project influence area, not just within the delineated footprint.
A hole PLAN found in the agency’s own analysis, quote verified against the document
- PendingThe document adopts a 35-year design life correlating to 2060 and uses the NOAA intermediate SLR scenario of 1.44 ft for that period.
The document adopts a 35-year design life correlating to 2060 and uses the NOAA intermediate SLR scenario of 1.44 ft for that period. However, NOAA's Sea Level Rise Viewer also provides higher scenarios, and the document does not explain why the intermediate scenario is selected over a higher scenario for a coastal structure protecting irreplaceable archaeological resources. The document itself acknowledges that complete avoidance of storm-driven flood risk is unlikely and that the wall will not prevent overtopping during a 100-year storm. Using a more conservative SLR scenario could change both the CISA elevation and the adequacy of the proposed wall height. The agency should disclose why the intermediate rather than the intermediate-high or high scenario is used to size a structure protecting non-replaceable cultural resources.
A hole PLAN found in the agency’s own analysis, quote verified against the document
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