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This raster layer serves as the results of the 2025 CPRA geostatistical analysis of reported subsidence rates. Band 1 represents the predicted subsidence rate [mm/yr] of a log-transformed, first-order trend removed, 'optimized' J-Bessel function Universal Kriging Model. Band 2 represents the standard error surface of this model [mm/yr]. This layer can serve as the boundary condition for the Integrated Compartment Model used by CPRA. The full report associated with this layer is found at:
Coastal Protection and Restoration Authority (CPRA), 2025. Development of a Continuous Prediction Surface of Subsidence Rates across the Louisiana Coast. Coastal Protection and Restoration Authority of Louisiana (CPRA), Baton Rouge, LA, 22p. plus appendices. https://cims.coastal.la.gov/RecordDetail.aspx?Root=0&sid=26794.
<DIV STYLE="text-align:Left;"><DIV><DIV><P STYLE="margin:0 0 16 0;"><SPAN><SPAN>Subsidence is a primary component of land loss in southern Louisiana and a major source of uncertainty affecting the planning and implementation of coastal restoration and protection projects. It is of particular importance for the Louisiana Coastal Protection and Restoration Authority to understand the rates at which the coastal landscape is subsiding to ensure proper development and implementation of its coastal master plan.</SPAN></SPAN></P><P STYLE="margin:0 0 16 0;"><SPAN><SPAN>The State of Louisiana has funded several studies and data collection efforts to better quantify rates of land subsidence. These efforts typically have focused on data collection and specific measurement techniques or understanding specific geologic processes. Few studies have attempted to predict subsidence rates on a coastal scale using geostatistical techniques, rather, previous maps of subsidence rates have focused on delineating zones of plausible ranges based on expert opinion of geologic phenomenon and features.</SPAN></SPAN></P><P STYLE="margin:0 0 16 0;"><SPAN>Though potentially useful in some cases, ranges of subsidence rates are insufficient for use in models or planning tools that require a single quantified rate of subsidence for a specific local. This layer represents the results of a study that developed a Universal Kriging interpolation model and its application to develop a subsidence prediction surface and associated uncertainty within the Louisiana coast. Model and interpolation errors are quantified and reported to help inform the potential uncertainty related to interpolation. The layer was fit to a 30 m grid used by the CPRA Master Plan team, and is further discussed in CPRA, 2025.</SPAN></P></DIV></DIV></DIV>
Suggested Citation: Coastal Protection and Restoration Authority (CPRA), 2025. CPRA Predictive Subsidence Surface 2025, Coastal Protection and Restoration Authority of Louisiana (CPRA), Baton Rouge, LA
Primary Author: Matthew Vincent
CPRA Predictive Subsidence Surface 2025
Matthew Vincent
Louisiana Coastal Protection and Restoration Authority
Geologist
150 Terrace Ave
Baton Rouge
LA
70802
matthew.vincent@la.gov
US
2253424752
Matthew Vincent
Rocky Wager
Louisiana Coastal Protection and Restoration Authority
DCL-B
150 Terrace Ave
Baton Rouge
LA
70802
rocky.wager@la.gov
US
2253421485
Rocky Wager
2025-07-15T00:00:00
2025-07-15T00:00:00
2025-07-15T00:00:00
subsidence; vertical land motion; kriging; geostatistics; CPRA; coastal; restoration; model; Louisiana
1
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The model covers the Louisiana Coastal Zone. Subsidence rates were derived from records extending from
1936-01-01T00:00:00
2021-01-01T00:00:00
<DIV STYLE="text-align:Left;"><DIV><DIV><P><SPAN><SPAN>These data represent the results of data collection/processing for a specific activity and indicates the general existing conditions at the time of collection. As such, it is only valid for its intended use, content, time, and accuracy specifications. The user is responsible for the results of an application of the data other than its intended purpose.</SPAN></SPAN></P><P /><P><SPAN /></P></DIV></DIV></DIV>
Esri ArcGIS 13.2.2.49743
20250811
This interpolated surface was informed using subsidence rates developed by Applied Coastal (2022; 2021; 2019; 2018) as part of SWAMP. Subsidence rates developed under SWAMP were derived from GPS survey records of geodetic monuments and tide gauges. For this study, a comprehensive point dataset was created by merging the monument derived and tidally derived subsidence rates into one feature class. Survey coverage in the Chandeleur islands was non-existent, so in order to reduce model error and provide better estimates in this region subsidence rates in the Chandeleurs were informed from the benchmark-derived subsidence rate used in the Chandeleur Operational Sediment Budget (Flocks et al., 2022) and added to the point dataset. The combined dataset provided 119 points across coastal Louisiana, each with unique subsidence rates.
The point features were loaded in to ArcGIS Pro and geographic interpolations were completed using ESRI's ArcGIS Pro Geostatistical Wizard. The final interpolation model utilized in this study was Universal Kriging (UK). A logarithmic transformation was applied and a first order trend was removed. The J-Bessel function was fit to the semivariogram, and the function was optimized using the “optimize” model option in the Geostatistical Wizard. The UK model results were then snapped and extrapolated to the same 30 m grid used for the ICM model domain. Results were masked to the LA-0284 project boundary, which limits the extrapolation of the model to a reasonable coastal area.
The LA-0284 project boundary was used to delineate the mask of this raster.
https://cims.coastal.louisiana.gov/viewer/metadata/zips/CPRA_Projects.zip
LA-0284 Boundary
The ICM model domain and 30 m grid that was used as the grid the interpolated model was fit to and snapped to.
https://files.mpdap.coastal.la.gov/static/model-geometries.zip
ICM Model Domain
The SWAMP subsidence rates used to develop the interpolated surface. These rates were derived from GPS monuments and tide gauges by Applied Coastal.
https://cims.coastal.louisiana.gov/RecordDetail.aspx?Root=0&sid=24941
SWAMP Subsidence Rates
The location of the MARK GPS monument used in the operational sediment budget for the Chandeleur Islands.
https://cims.coastal.louisiana.gov/meta_docs/gis_refs/2016_GPS_Benchmarks/PDF/MARK.pdf
Chandeleur Island Subsidence Rates
Subsidence rates developed under SWAMP were derived from GPS survey records of geodetic monuments and tide gauges. For this study, a comprehensive point dataset was created by merging the monument derived and tidally derived subsidence rates into one feature class. Survey coverage in the Chandeleur islands was non-existent, so in order to reduce model error and provide better estimates in this region subsidence rates in the Chandeleurs were informed from the benchmark-derived subsidence rate used in the Chandeleur Operational Sediment Budget (Flocks et al., 2022) and added to the point dataset. The combined dataset provided 119 points across coastal Louisiana, each with unique subsidence rates. The point features were loaded in to ArcGIS Pro and geographic interpolations were completed using ESRI's ArcGIS Pro Geostatistical Wizard. The final interpolation model utilized in this study was Universal Kriging (UK). A logarithmic transformation was applied and a first order trend was removed. The J-Bessel function was fit to the semivariogram, and the function was optimized using the “optimize” model option in the Geostatistical Wizard. The UK model results were then snapped and extrapolated to the same 30 m grid used for the ICM model domain. The raster was masked by the LA-0284 project boundary and both the prediction and standard error surfaces were combined into a multiband raster.
2025-07-15T00:00:00
To predict the subsidence rates across the entire coast of Louisiana.
Matthew Vincent
Louisiana Coastal Protection and Restoration Authority
Geologist
150 Terrace Ave
Baton Rouge
LA
70802
matthew.vincent@la.gov
US
2253424752
Matthew Vincent
Matthew Vincent
The development and subsequent removal of the trend assumed several broad generalizations and simplifications as to the extent of the Holocene surface and its impact on subsidence. Subsidence rates used to inform this surface are also believed to be true and the uncertainty from these derived rates are not accounted for.
Only subsidence rates from the associated studies were used in this model. Specific geologic features were not delineated.
Matthew Vincent
Louisiana Coastal Protection and Restoration Authority
Geologist
150 Terrace Ave
Baton Rouge
LA
70802
matthew.vincent@la.gov
US
2253424752
Rocky Wager
Louisiana Coastal Protection and Restoration Authority
DCL-B
150 Terrace Ave
Baton Rouge
LA
70802
rocky.wager@la.gov
US
2253421485
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