USACE
Modeling Errors impact on St. Tammany Parish
The Corps has finally released their surge models that show the
south shore barriers have significantly affected the surge risk in St. Tammany
Parish.
Before Congress authorizes an additional $3.2 Billion to repair
the sinking
Tom Thompson
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Supporting documentation:
November 2012,
Corps held a public meeting to present their finding on HSDRRS
flood impact from hurricane Isaac. At the meeting, Colonel
Fleming, Commander of the Corps’ New Orleans District Office, stated the
Corps has a policy of accepting responsibility to mitigate problems their
projects cause.
https://www.youtube.com/watch?v=e-JEK7cF4EQ&feature=youtu.be
As of this date, the Corps has not admitted to, or accepted
responsibility for, increased flood risk caused by their structures
April 2013,
Corps agreed to model
Once the models were released in 2018, they were found to be
extremely inaccurate and “significantly” underestimated the HSDRRS impact on
St. Tammany Parish.
See
attached: “2013 April Corps'
March 2018,
A Freedom of Information Act (FOIA) request was made to release
the Corps’ Evaluation of Storm Surge with and without the HSDRRS.
June 2018,
The Corps of Engineers denied the FOIA request to release their
HSDRRS impact report, claiming “deliberative process privilege”.
July 2018,
A Freedom of Information Act FOIA appeal request was made to
release the Corps’ Evaluation of Storm Surge with and without the HSDRRS.
August 2018,
In response to the FOIA appeal, the Corps of Engineers released
their evaluation of storm surge outside of the HSDRRS. The report
contained inaccurate topographic data in their baseline 1965 model
(pre-HSDRRS). The Corps modeled a nonexistent, 14 foot high levee
that reduced
See
attached: “Errors found in 2018 August Model”
January 2020,
Based upon comments received, the Corps of Engineers revised their
original HSDRRS impact study by issuing an Appendix D to correct the 1965
baseline model and their findings.
The corrected 1965 model, removed the nonexistent 14 foot high
levee, but replaced it with a 9 foot high railroad embankment that Corps’
documents said could not function as a levee. The railroad embankment
also incorrectly restricted
See
attached: “Errors found in 2020 January Model”
February 2020,
Based upon comments received, the Corps of Engineers once again
revised their HSDRRS impact study and removed the railroad embankment
structure, which increased
This revised study shows the HSDRRS has increase storm surge
by approximately 5” at Eden Isles and roughly 8 to 10” between Slidell and
Pearlington (See page 8 of 14 of the Appendix D revision)*
See
attached: “2020 February Corps response to errors”
See
attached: “2020 February Revised model Data APPENDIX D”
* Note: an increase of less than 6” to
Despite Corps’ models showing HSDRRS impact to St. Tammany
Parish, the Corps has not admitted the impact to St. Tammany Parish or
committed to mitigating/alleviating the increased surge into St. Tammany
Parish.
This is why Congress
should extend HSDRRS
protection to St. Tammany Parish and include St. Tammany Parish
protection into any
additional HSDRRS
funding request.