Floodplain Fiasco: SEMA Says Lake Of The Ozarks Maps Are A Work In Progress

Since December 2024, Lake of the Ozarks homeowners and real estate professionals have been raising concerns about potential Federal Emergency Management Agency (FEMA) floodplain map revisions. And while an executive order by President Trump put a hiatus on FEMA’s plans, some Lake area real estate professionals continued to raise concerns about the State Emergency Management Agency’s (SEMA) plans.

Jeff Vernetti (R-District 123) addressed citizen concerns about proposed changes to Lake of the Ozarks floodplain maps in his Monday, March 10 capital update newsletter, saying that since November he has been working to stop the State Emergency Management Agency (SEMA) from proceeding with a plan to update floodplain maps for Lake of the Ozarks.

“Those contracted with the project obviously have little knowledge of the Lake or its geography - nor did they research the plethora of data showing current maps are accurate,” Rep. Vernetti wrote. “Instead, they preemptively released data from incomplete processes and panicked our community. This is unacceptable.”

After several weeks of frustrating communication with the State Emergency Management Agency (SEMA) — and with the contractor hired to revisit the maps — Vernetti sent a letter to Governor Mike Kehoe asking his administration to intervene.

Click here to read Vernetti’s letter to Governor Kehoe.

A LakeExpo.com article published on March 11 prompted a response from SEMA, who provided a clarifying Q&A-style document. In it, SEMA acknowledged a major floodplain remapping project, but said the preliminary data (displayed as map overlays) that had been made available online and for local real estate professionals had been errant and were still subject to significant revisions. That data had shown areas of the Lake of the Ozarks in which the new proposed floodplain lines would have put thousands of homes within the floodplain — shockingly, as some of those homes sat above the elevation of Bagnell Dam.

“In the interest of transparency, SEMA made initial flood risk data available on a publicly accessible website,” the agency wrote. “It was determined this data did not account for all the complicated characteristics of the Lake of the Ozarks. The flood risk data has been misinterpreted to mean that flood elevations in some areas could be raised by several feet. However, while more complete analysis is still being conducted, incorporating the lake bathymetry into the modeling is expected to considerably lower the water surface elevations from the flood risk data initially released.”

The next day, in a capitol report newsletter sent out on Wednesday, March 12, Vernetti again addressed the SEMA issue, saying he had met with the Director of Public Safety (DPS) to review the community’s concerns about SEMA.

“After months of frustrating communication from SEMA and its contractor, I finally believe we have someone at the agency who understands our concerns and am confident our voices will be heard moving forward,” Vernetti wrote. “It helps that DPS Director Mark James lives at the Lake and understands our geography and how flooding is controlled in our unique environment.”

Vernetti said Director James acknowledged there had been issues with communication and promised for more transparency in the process.

“I will continue to advocate for no change to the floodplain, as I stated in my recent letter to Governor Mike Kehoe,” Rep. Vernetti added.

To contact Rep. Vernetti email Jeff.Vernetti@house.mo.gov, or call 573-751-1119.

Contact Governor Mike Kehoe at (573) 751-3222, or email through his online portal at https://governor.mo.gov/contact-us/mo-governor.

**Vernetti included the following Department of Public Safety (DPS) response to the concerns surrounding the new Lake of the Ozarks Floodplain Maps in his Wednesday, March 12 newsletter correspondence.**

DPS responds to local concerns about the floodplain mapping project for Benton, Camden, Miller and Morgan Counties

The floodplain mapping project

DPS on Tuesday, March 4 responded saying in August 2020, SEMA began a multi-year flood risk data and floodplain mapping project to provide updated maps of flood risks for the Osage River Watershed in Missouri. The Lake of the Ozark counties of Benton, Camden, Miller and Morgan are included in the study area. This process is designed to incorporate the latest data and technology, along with input from local officials, floodplain administrators and the general public. These updates can take five to seven years or longer to complete depending on available funding. This project has been fully funded by FEMA.

Data collection and analysis

To develop the most accurate, up-to-date flood risk data possible, our teams follow established data collection and analysis processes. This involves analyzing water runoff patterns, ponding and storage areas, precipitation frequency and volume, soil types, land use, and topography (LiDAR – collected by aircraft). In the Lake of the Ozarks study area, updated analysis will be incorporating the acquired lake bathymetry. Bathymetry provides a description of the underwater terrain (depth and storage capacity) and how water moves through the lake, which significantly improves our understanding of water flow dynamics. However, incorporating this data required additional time.

Complications with the Lake of the Ozarks project

In the interest of transparency, SEMA made initial flood risk data available on a publicly accessible website. It was determined this data did not account for all the complicated characteristics of the Lake of the Ozarks. The flood risk data has been misinterpreted to mean that flood elevations in some areas could be raised by several feet. However, while more complete analysis is still being conducted, incorporating the lake bathymetry into the modeling is expected to considerably lower the water surface elevations from the flood risk data initially released.

Where we are now: draft flood risk data

The Lake of the Ozarks project is an active, ongoing effort, with the draft data still being refined to incorporate the lake bathymetry. There is no preliminary map at this stage, as this will only occur once all data has been integrated into the analysis and modeling process. It typically takes up to two years following preliminary issuance for the new maps to become effective. Until then, the current adopted effective maps will remain in place (Camden, Miller and Morgan counties adopted their maps in 2018; Benton County adopted its map in 2009).

Once the analysis is complete, the flood risk data will be made available for review to floodplain administrators, emergency managers and local officials. This same information will be distributed at Flood Risk Review (FRR) meetings for Benton, Camden, Miller and Morgan counties to discuss changes to the data. Community officials and stakeholders will be provided with a 30-day comment period following the FRR meetings.

Next steps

The bathymetry data has been incorporated into the initial flood risk data and is currently undergoing analysis through a series of computer models, which will be combined for a comprehensive assessment. Due to the volume of data to be analyzed, this process takes a considerable amount of time. It is anticipated that it will be late fall of 2025 before SEMA can proceed with preliminary issuance of the flood risk data and floodplain maps. Again, there is NO proposal or preliminary map at this time. It takes up to two years following preliminary issuance for new maps to become effective. The current effective floodplain maps that communities have adopted will remain in effect until that time.

SEMA will continue to communicate and receive input from officials and the public throughout the process. Local input is essential when developing accurate flood risk data. SEMA appreciates those who have participated and looks forward to continued participation throughout the process.

What is SEMA/FEMA’s role in floodplain mapping?

FEMA works with state partners, such as SEMA, that apply for participation in the Cooperating Technical Partners (CTP) program. SEMA has maintained a formal CTP partnership agreement with FEMA since June 1999. As a CPT, SEMA helps local communities that participate in the National Flood Insurance Program (NFIP) with hazard identification and risk assessment and provides support, data and other resources needed for local officials to make decisions about floodplain management. The authorizing authority for the CTP Program is the National Flood Insurance Act of 1968 and the Biggert-Waters Flood Insurance Reform Act of 2012. SEMA applies to FEMA for grants and uses a contractor called WSP to perform the work in coordination with SEMA’s Floodplain Mapping Section.

Does Missouri use climate-informed science approach (CISA)?

No climate change data is associated with the data sets used in the Lake of the Ozarks floodplain mapping project. SEMA has no agreement with FEMA in its statement of work to utilize anything except modeling based on existing conditions and the best available data and technology. SEMA does not utilize the Climate-Informed Science Approach (CISA), which was introduced under EO 13690 as part of the Federal Flood Risk Management Standard (FFRMS).

Two presidential executive orders related to floodplains, EO 13690 and EO 14030, have received attention from those concerned about the current Lake of the Ozarks mapping project. Neither of these executive orders from the Obama and Biden administrations affected SEMA’s flood mapping project. President Trump rescinded both EO 13690 and EO14030 when he took office in January 2025. He had rescinded President Obama’s EO 13690 during his first term; President Biden’s EO 14030 had restored provisions of EO 13690.

Are drones being deployed for the Lake of the Ozarks project, either to map the shape of the ground (topography) or the underwater terrain of the lakebed (bathymetry)?

No, drones are not being used for this project. Given the large project area, LiDAR would have been collected by planes rather than drones to map the topography. Floodplain mapping efforts rely on data from federal and state partners, such as the U.S. Department of Agriculture’s Natural Resources Conservation Service (USDA NRCS), which last conducted aerial data collection for Camden, Miller, and Morgan counties in 2017 and Benton County in 2023. Bathymetry is collected using sonar (sound navigation and ranging) mounted on boats, not aircraft.

Is participation in the NFIP required?

Communities are not legally required to participate in the National Flood Insurance Program, (NFIP). Participation is voluntary to obtain access to NFIP flood insurance, and local officials may choose to drop out of the program at any time.

As part of a community’s agreement to participate in the NFIP, it must adopt and enforce floodplain management regulations, including flood maps. FEMA has set forth in federal regulations the minimum standards required for participation in the NFIP; however, legal enforcement of floodplain management standards is the responsibility of the participating NFIP community, which can also elect to adopt higher standards to mitigate flood risk.

If a community does not pass an ordinance that adopts updated flood maps before they become effective, the community will be immediately suspended from the program. When a community is suspended from the NFIP, no property owner or renter will be able to purchase a new NFIP policy, and existing policies will not be renewed. SEMA’s Floodplain Management Section assists communities with joining the NFIP and maintaining compliance.

Contact:

SEMA sema.dps.mo.gov, 573-526-9100, or mosema@sema.dps.mo.gov

FEMA www.fema.gov/about/contact or 800-621-FEMA

National Flood Insurance Program, FEME Mapping and Insurance Xchange Center: 877-336-2627