About a month ago I submitted an open records request with FEMA to obtain the documentation that was submitted by Mystic during their floodplain "appeals" process. I finally received the documents and I am sharing them at the links below. These documents are all part of public record and have been redacted, so I don't see any issue with posting these documents for the purpose of transparency.
pxl.to/Mystic-Guadalupe-LOMA-part1pxl.to/Mystic-Guadalupe-LOMA-part2pxl.to/Mystic-Guadalupe-LOMA-part3pxl.to/Mystic-Guadalupe-LOMA-part4pxl.to/Mystic-Cypress-Lake-LOMA-part1pxl.to/Mystic-Cypress-Lake-LOMA-part2Here are my thoughts after reviewing the documents:
First, some history on the FEMA Flood Insurance Rate Maps (FIRM) for Kerr County. The original FIRM was issued in 1979 and was drawn on mylar paper at a scale of 1 inch = 2000 feet. The FIRM was based on a detailed study and hydraulic analysis of the South Fork. A detailed study was not done for smaller creeks (Cypress Creek/Edmunson Creek) but the analysis did account for flow from those smaller creeks into the South Fork. The design rainstorm event was based on USWB Tech Paper No. 40 with a 24 hour total rainfall of about 9.5 inches. The topography was based on USGS maps with a contour interval of 20 feet. The FIRM showed a 100-year flood elevation (BFE) of 1840' in the middle of the Mystic golf course and 1835' near the Mystic dam. The large scale size of the map made it difficult to determine which portions of the property were in the floodplain. The only accurate method for determining the floodplain boundary would have been a field survey of the ground elevations throughout the camp.
In 2011, the paper map was converted into a digital format. FEMA relied on the original hydraulic analysis and topographic data from 1979 and the digitization process carried over many inaccuracies from the original study. Those inaccuracies became highly visible by zooming in and viewing at much smaller scale than was originally intended. Many of the cabins and buildings throughout Mystic were shown to be in the floodplain even though the BFE was unchanged from 1979 to 2011.
In 2013, Mystic hired an engineer/surveyor to perform a field survey to determine which buildings were in the 100-year floodplain and to submit a Letter of Map Amendment (LOMA) to FEMA. A detailed hydraulic study was also performed for the portions of Cypress Creek and Edmonson Creek where there was no published BFE. The field survey determined that the Lowest Adjacent Grade (LAG) outside many of the buildings (39 total) was higher than the BFE. The survey also found several buildings (6 total) where the LAG was lower than BFE. Buildings that were already drawn outside the floodplain were not surveyed. On August 19, 2013, the LOMA was submitted to FEMA requesting 39 buildings be removed from the 100-year floodplain boundary. On October 15, 2013 FEMA approved the LOMA and officially removed a total of 40 buildings from the 100-year floodplain and/or floodway.
Only one LOMA application was submitted in 2013 but four different Letter of Map Change determination documents were issued and summarized below:
- 13-06-4293A, LOMA, 24 buildings total
- 14-06-0077A, LOMA-DEN (LOMA denial) 6 buildings (Mystic did not request these buildings to be removed from the floodplain but did include the survey data)
- 14-06-0062A, LOMA-OAS (Out As Shown), 1 building
- 14-06-0124A, LOMR-FW, 15 buildings total (specific type of LOMA for buildings mapped in the floodway)
The elevation certificates included with the LOMA application indicate the Highest and Lowest Adjacent Grade, Floor Elevation, and 100-year Base Flood Elevation.
For the cabins on the flats, LAG was about 2 to 6 feet higher than BFE and the floors of the cabins were about 3.5-7.5 feet higher than BFE (freeboard). The ground slopes down along the side of Bug House and corner closest to the river was slightly lower than BFE, so that cabin remained in the 100-year floodplain while the floor is 3.5 feet higher than BFE.
For the cabins on Senior Hill, LAG was about 7 to 22 feet higher than BFE and the floors were about 8.8 to 24 feet above BFE. For Hang Over, the LAG is measured where the wood framing is in contact with the hill below, so that cabin remains in the 100-year floodplain while the floor is 8.8 feet higher than BFE.
At Mystic Cypress Lake, FEMA had not yet performed a detailed study for Cypress Creek to determine BFE's. Prior to construction of the new camp, Mystic hired an engineer/surveyor to perform a field survey to determine the LAG at the proposed new building locations and to perform a detailed hydraulic study for Cypress Creek. The LOMA application was submitted 9/23/2019 and approved by FEMA on 11/12/2019. FEMA determined that all of the Cypress Lake buildings are outside the 500-year floodplain.
So what does that all mean? The LOMA at Mystic was not the result of a loophole or political favor or some purely administrative process. An extensive field survey was conducted and a detailed hydraulic study of Cypress/Edmonson Creek was performed to supplement FEMA's detailed study of the South Fork. Many of the buildings appear to be legitimately outside the floodplain. FEMA calls this an "inadvertent inclusion" which is common for older FIRM's.
For those that are still skeptical of the FEMA floodplain "appeals" process, two more recent FEMA studies provide additional validation that the Mystic buildings are actually outside the 100-year floodplain.
In 2016, FEMA (via global engineering company AECOM/Compass) performed a 1D Base Level Engineering study of the Upper Guadalupe watershed. The focus of the study was to more accurately model smaller creeks and streams (such as Cypress Creek and Edmunson Creek) and to incorporate more accurate LIDAR topography elevation data. This study shows a higher BFE throughout the watershed (about 2.5 feet higher than the current published BFE at Mystic) but the entire flats area is still shown outside the 100-year floodplain. The floodplain boundary from that model can be viewed on the FEMA estBFE Viewer here:
https://webapps.usgs.gov/infrm/estbfe/ and the report can be viewed here:
pxl.to/2016-FEMA-BLE-Report In 2024, FEMA (via AECOM/Compass) performed a 2D Base Level Engineering study of the Upper Guadalupe watershed. The study incorporated increased rainfall amounts from NOAA Atlas 14 (11.7 inches for 24 hour storm, 19% increase compared to previous which was updated in 2018 partly in response to the Wimberley flood and Hurricane Harvey). The study also incorporates shorter duration/higher intensity storms. This study, which I think is preliminary and still being reviewed by FEMA, also indicates a higher BFE throughout the entire watershed (about 4.5 feet higher than the current published BFE at Mystic). Much of the flats area is still shown to be outside the 100-year floodplain. That report can be viewed here:
pxl.to/2024-FEMA-BLE-Report It is unclear why these newer studies have not yet been incorporated into the Kerr County FIRM yet. FEMA is required to review and/or update the current FIRM every 5 years. The last update to the FIS was in 2020, so maybe the FIRM will be updated soon.
A few other thoughts as it relates to the flood at Mystic. Most jurisdictions, including Kerr County, require that new buildings be elevated above 1 foot above the BFE. The 1 foot minimum freeboard height applies to residential, commercial, schools, etc. An additional foot of freeboard height is required for hospitals, police/fire stations, and other critical facilities. At Mystic, the smallest freeboard height is about 3.5 feet at Bug House. Therefore, the current cabins meet the code elevation requirements for critical facilities. This is likely why the cabins were referred to as being
"constructed on high, safe locations."Regarding Mystic's emergency plan for floods. They did have a plan. It wasn't a robust plan, but the plan involved sheltering in the place during a flood
"unless told otherwise by the office". The "
unless told otherwise" aspect of the plan on July 4 involved a phased evacuation of the cabins starting with Bug House closest to the river. This seems logical based on the freeboard heights of each cabin. The four cabins closest to Rec Hall have a freeboard height of about 6 to 7 feet. Rec Hall has a freeboard height of 7.5 feet. Absent an evacuation order from the county, it does seem reasonable to shelter in place inside the cabins.
According to the USGS high water marks, the flood was about 14 to 17 feet higher than the 100-year flood elevation and about 4 to 7 feet higher than the 500-year flood elevation at Mystic Guadalupe. At Mystic Cypress Lake, the flood was several feet less than the 100-year flood elevation.
All of the info referenced above can be seen in this interactive map which has the LOMA elevation info, USGS high water marks, and floodplain boundaries from the current FIRM, the 2016 BLE study, and the 2024 BLE study:
arcg.is/T0y5zI have written previously about the inadequacy of the timing and information included in the NWS flood warnings. A summary can be found here:
https://pxl.to/Mystic-NWS-Flash-Flood-Warning-Analysis But clearly based on the outcome of July 4, elevating 1 foot above BFE does not provide adequate life safety. The American Society of Civil Engineers has recognized this and in 2025 published updated recommendations to their Flood Resistant Design and Construction standard. For residential and commercial buildings, they now recommend that those buildings be elevated at or above the 500-year flood elevation. Elementary schools would be elevated above the 750-year flood, and hospitals/police/fire stations/critical facilities would be elevated above the 1000-year flood. The previous version of this document is incorporated by reference into the 2024 International Building Code, so these updated recommendations won't go into effect until the 2027 code cycle at the earliest. However, many local jurisdictions do not adopt the latest code immediately, so it could be even longer until these recommendations get widespread adoption.
If we truely want to prevent this tragedy from happening in the future, we need to have a full picture understanding of what happened in order to implement effective change. While better communication and planning may have helped, the primary issue that needs to be solved is how to be safe during a rapid flood that exceeds the 500-year flood elevation in a matter of a couple of hours. Arguing about LOMA appeals and what is the actual 100-year floodplain boundary doesn't matter for a flood that is 14-17 feet higher than the 100-year BFE.
While the current proposed legislation does contain some positive changes, many of the weaknesses that were exposed in the July 4 flooding are not adequately addressed in SB1 or HB1. For example, walkie talkies are not required in each cabin and the PA system is not required to have a redundant power source. And while cabins would no longer be allowed in the 100-year floodplain, they would still be allowed in the 500-year floodplain. Only the areas of camp within the 100-year floodplain would be required to evacuate when an NWS flood warning is issued. Based on what we have learned after the July 4 flood, it seems imperative that cabins in the 500-year floodplain also evacuate (and have a safe location above the 500-year flood to evacuate to).
You can read the current language of the bills here:
capitol.texas.gov/tlodocs/892/billtext/html/SB00001E.htmcapitol.texas.gov/tlodocs/892/billtext/html/HB00001E.htm And an example of how the bill would impact Mystic/La Junta/HOH here:
pxl.to/SB1-examples 
