The Federal Emergency Management Agency’s flood maps plan for the Utah Lake shoreline and Provo River have not been updated since the 1980s.

But after a decade-plus-long effort by state and local officials to help FEMA modernize the maps to reflect current climatic, ecological and developmental circumstances, the new proposed maps have reached the final stages.

The project is in a 90-day appeal period until March 18, after which the plans are expected to go into effect nine months to a year later, estimated Jamie Huff, the state of Utah’s floodplain mapping program manager.

The role of the flood maps is to project certain areas that would be impacted by floodwater during an extreme flood event. The maps have implications on flood insurance rates for homes and businesses. FEMA’s updated versions show both increases and decreases to flood threats in different areas near Utah Lake and the Provo River.

One area seeing an increase in flood risk is between Geneva Road and Utah Lake, according to Provo Floodplain Administrator Jacob O’Bryant.

“There are several blocks of homes on either side of the river that are impacted in that area west of Geneva Road,” O’Bryant said.

The increased flood risk in the area comes largely because the Provo River’s levees, which were implemented in the 1980s to hold water within the lower Provo River, no longer meet federal flood protection standards.

As a result, they can’t be factored into the development of the new flood plan, according to Huff.

“We had to map it as if the levee wasn’t there, because it cannot show protection from the 1% annual chance of flooding,” Huff said.

O’Bryant added that the levees have aged over time, with tree roots growing through some. The city is actively trying to update the levees; however, doing so would likely require state or federal assistance.

“It’s a fairly significant project,” O’Bryant said. “It involves right-of-way, private properties, trying to protect vegetation and trees along the river, and surrounding the Provo Airport as well.”

Levees aside, many areas in the county are not projected to have an increase in flood risk with the new plan. Recent weather patterns play a role. When FEMA created its last plan in the 1980s, it was after a wet time period. The 40 years since have been dryer.

“A flood map can change over time,” Huff said. “It can increase or it can decrease because of all of that historical information. So if we have longer periods of more rainy weather and more precipitation and hydrology coming into the system, that would be factored in and could potentially increase floodplain designation, or, on the flip side, if we have less precipitation over a certain period of time, that could potentially decrease a little bit.”

Also taken into account in the new plan is the Jordanelle Reservoir and dam that were built in 1993 and slow the water outflow into Provo River and Utah Lake.

“The water coming down the Provo River has decreased from the 1980s to now,” Huff said. “We were able to take Jordanelle information, and in conjunction with the dryer years of precipitation in the rest of the watershed, we were able to reduce the hydrology, the cubic-feet-per-second flows for the Provo River.”

One city where the projected flood map changes are minimal is Saratoga Springs.

“I am aware that these changes are much more significant to Provo. … Generally in Saratoga, we haven’t seen these changes really affect existing development,” Saratoga Springs Floodplain Manager Jeremy Lapin said. “They may have minor impacts on undeveloped property, and they may impact a few homes that were built along the shoreline pre-incorporation. I think there’s less than three or four of them.”

The new flood maps can be viewed by visiting FEMA’s map service center. For more information on flood maps, visit the Utah Division of Emergency Management’s website.