Mike Reicher

mreicher@tennessean.com

While stretches of Cooper Creek remain dry for most of the year, East Nashville resident Mitch Hansen has seen the creek come alive. Heavy rains flooded his Inglewood house in 2010 and again in 2013.

Now, the federal government officially recognizes the risk. The Federal Emergency Management Agency last month finalized revised flood maps for Davidson county, and more than 4,400 properties were added to high-risk zones, including many on small creeks like Cooper.

Thousands of property owners may have to purchase flood insurance policies for the first time. Mortgage companies typically require coverage if a property falls into the 100-year floodplain -- an area with a 1 percent chance of being inundated each year. For some recent buyers, the designation could be the first they learn of flooding risks.

“I should have known better when I bought it in 2008,” said Hansen, recalling when he saw the rain swelling in the creek at the time. “I was like, ‘wonder if that happens often?’”

Hansen now has flood insurance, but he didn’t when the epic 2010 rainfall caused about $2,000 of damage to his heating and air-conditioning system and ruined about $10,000 of his music production equipment.

Flood risk models are based on rainfall, river flow, topography, flood-control measures and changes from building and development.

Since the last update in 2001, engineers flew laser instruments over more areas of the county, improving topographic base maps, said Tom Palko, assistant director of stormwater at Metro Water Services. That allowed more accurate flood modeling. Also, the U.S. Army Corps of Engineers surveyed land not previously studied in detail, such as the area around Cooper Creek.

“The intent of the flood maps is to identify risk,” Palko said. “If an area was previously unstudied, then we did not know the risk associated with living or building in that area.”

Most of the flood boundaries in the county changed by one or two feet. Parts of the Harpeth River, for instance, saw floodplains rise by a foot. Some areas with new development are at a higher elevation than before, and now out of the floodplain.

To see if a property was added to a hazard zone, visit maps.nashville.gov/PrelimFEMAViewer. Homeowners may be exempt from insurance if the floodway covers a portion of a lot, but doesn't touch the home itself.

Metro officials will use the new maps to guide future construction. No new buildings will be allowed in the floodway -- the area of the floodplain where waters usually flow faster and deeper. And new construction in the 100-year floodplain must be offset by removing an equal amount of land to accommodate the flow of floodwaters.

Homeowners whose properties fall into the floodplain may be eligible for subsidized policies through the National Flood Insurance Program. But they have to sign up before the maps become effective in April. An average flood insurance premium costs about $700 per year, according to federal officials.

To determine the exact premium, homeowners have to first survey their properties and calculate their flooding risk. Professional surveys can cost more than $500, Palko said.

For her neighbors on a fixed income, flood insurance could be cost-prohibitive, said Ruby Baker, the president of the Bordeaux Hills Residents Association. Baker attended an open house on Monday to learn about insurance requirements.

“That’s going to be a huge burden,” she said. “After their medications, utilities… they might just take the risk.”

Officials recommend that homeowners consider flood insurance even if their homes fall outside the 100-year boundary. Every property in Davidson County is eligible for flood insurance.

“A lot of people will carry it only because someone is making them carry it," Palko said. "That’s the mindset we’re trying to change."

Homes with federally-backed mortgages, such as those through the Veterans Administration or the Federal Housing Administration, are required to have flood insurance if they fall into the 100-year floodplain.

State law requires residential sellers to disclose if they are aware of any flooding problems, if the property has been damaged by floods, or if flood insurance is required. But if the seller isn’t aware of flooding issues, they aren’t required to do any research to answer the questions.

The impact on property values is harder to gauge. In a hot real estate market, buyers are more willing to choose properties in a flood zone, said Richard Exton of Manier & Exton Real Estate Appraisers.

“It might not show up in a price reduction,” he said, “but it might take longer to sell a property that is in a floodplain.”