Flood maps in Missouri are being updated, which could result in lower flood insurance rates for property owners when all the maps are completed.
Dan Johnson, public works director for the city of Joplin, updated the Joplin City Council on the map work at a meeting last week.
Johnson asked the council to approve the continuation of a contract with a local engineering firm, Allgeier Martin and Associates, to continue assisting the city with its storm sewer permit and to assist with the remapping project. This firm also works with Jasper County on county mapping.
Charla Geller, emergency management director for Newton County, said remapping work has also begun in Newton County.
The Federal Emergency Management Agency oversees a national mapping process every 10 years, Geller said. The difference this time is that drones have been used to capture images of the topography, allowing engineers to adjust for changes rather than relying on paper maps published in the 1940s and 1950s.
That means the new maps will be more accurate, Geller said, and could translate into lower flood insurance premiums for some property owners.
Johnson said the city and Allgeier’s flood mapping work is one of the projects that will be done in conjunction with Allgeier’s work to renew the city’s permit to discharge water collected in the city’s stormwater system.
While older cities in Missouri have combined storm and sanitary sewer systems, Joplin’s stormwater collection system is separate from its sanitary sewer system.
The permit for the storm water system is issued under the National Pollutant and Discharge System, and it’s part of the federal Clean Water Act, which is designed to reduce discharges into the nation’s waters, Johnson said. Joplin first received the permit in 2004.
But the contract renewal also provides engineering assistance for work related to National Flood Insurance Program remapping tasks.
Joplin and other communities have been part of the flood insurance programme since the late 1970s. Since then, the mapping of floodplains has reduced the likelihood of homes and businesses being flooded because it has helped guide construction decisions and the placement of homes to avoid areas of heavy flooding.
Johnson said the remapping of Missouri is being paid for by FEMA.
Currently, the flood maps for the region are from 2012. Remapping began in 2009 and was completed in 2011.
Johnson said the goals of the new mapping process are to produce improved, user-friendly maps. For example, the digital maps will show the base flood elevation for a house with one click on a computer.
The process requires input from local officials because “we want accurate maps,” Johnson said. “Staff need input to get the best maps. Many hours will be spent by staff to ensure that this process is followed to get the best map” with the most accurate details.
A draft mapping process will allow local engineers and officials to see the maps in progress and provide comments on changes or additions to make the maps more accurate.
“The mapping is based on 2021 imagery, so anything that has changed since then we need to comment on what is different,” Johnson said. For example, a draft map for south Joplin “shows a floodway that goes down the middle of Range Line, so we need to comment and ask if a drain that was built under I-44 was included.
If not, it needs to be added to the map so it doesn’t look like Range Line is heavily flooded.
Councilman Phil Stinnett said a detention system recently built in the area on Arizona Avenue near 32nd Street should help the downstream floodplain, but that won’t help flood insurance rates if a lower floodplain shows up on a new map.
“Anything the city has done (to reduce flooding) should help downstream homeowners with lower homeowner rates,” he said.
Geller also said the new maps could have an impact on flood insurance rates.
Johnson said a city stormwater project at 25th Street and Davis Boulevard removed 18 structures from the floodplain, which should result in a reduction in insurance costs for each.
Engineers and government officials also need to review the maps to make sure all recent underground retention projects are reflected in the maps to make them as accurate as possible, he added.
The need for input means the maps will take some time to complete, he said.
