Alarmed by FEMA proposal, Boise River cities seek consensus on flood maps

NeighborWorks Boise CEO Bud Compher explains how a home in the Adams Street Cottages project in Garden City is built with a 4-foot-high stem wall instead of the standard 2-foot, in order to raise the house above what could soon be part of the Boise River’s floodplain.
NeighborWorks Boise CEO Bud Compher explains how a home in the Adams Street Cottages project in Garden City is built with a 4-foot-high stem wall instead of the standard 2-foot, in order to raise the house above what could soon be part of the Boise River’s floodplain. kgreen@idahostatesman.com

Hundreds of Treasure Valley homeowners will spend thousands more dollars each year if the Federal Emergency Management Agency’s newest flood maps are adopted.

The proposed maps, which could be finalized by mid-2017, would put more than three-quarters of Garden City in what the agency considers the Boise River’s floodplain. New floodplain areas would include almost all of the land south of the river between Garden City’s eastern tip and 46th Street, as well as most of the neighborhood south of State Street between Bogart Lane and Glenwood Street.

FEMA’s new maps also would add big chunks of Boise, including lots in the West End area where major projects are planned.

The floodplain is the land that FEMA predicts would be underwater in a 100-year flood — an event that has a “1 percent chance of being equaled or exceeded in any single year.”

Planners in cities from Boise to the mouth of the Snake River worry that expanding the area mapped as floodplain will drive up the cost and difficulty of buying, developing or living in floodplain properties. At least one developer is considering abandoning plans for a project due to the new maps, said Jenah Thornborrow, head of Garden City Development Services. Thornborrow wouldn’t say who the developer is.

Boise planning director Hal Simmons said being included in the floodplain could change some projects’ design standards in ways that don’t always fit city ideals. For example, instead of front doors right on sidewalks, buildings might have to be raised — and then set back a few feet so that stairs can reach the sidewalks. The effect would be to make these buildings less pedestrian-friendly.


The federal government creates and periodically updates flood maps to help communities all over the country decide where to build and live.

The goal of these maps is to limit damage and liability — and recriminations that always occur when properties are built where they shouldn’t be. And while we all know what a flood plain looks like, putting precise lines on a map takes a tricky combination of data and guesswork. The process becomes politicized, with implications for development, land values and financing.

As recently as 2006, high waters breached the Boise River’s banks, threatening homes in Star and Eagle. The event unleashed a rash of second-guessing and finger-pointing, and even a demand from some homeowners for the federal government to reconfigure flows around Eagle Island.

The last time the agency looked at the Boise River Drainage was the early 2000s. Early this year, FEMA released a group of proposed new maps that added thousands of acres in Canyon and Ada counties to the floodplain.

The total amount of land in the proposed new floodplain is a matter of some dispute. According to a Nov. 10 memo Simmons, city engineer John Tensen and flood expert Jim Wyllie sent to Mayor Dave Bieter and the City Council, the new map would add about 850 acres to the floodplain in Boise alone. But FEMA regional engineer David Ratte said the new areas added to the floodplain map are only 565 acres for all of Ada County.

The reason for this discrepancy is unclear.

Ratte said the amount of water entering the drainage wasn’t a factor in changing the Boise River floodplain because Lucky Peak Dam regulates flows between it and the Snake River.

“The changes reflect more what’s occurring on the ground, more sophisticated...hydraulic modeling, much, much better terrain data with (Light Detection and Ranging, a sensing method that uses a laser to measure distances), changes with the floodplain with respect to fill or development, more detail, more precision with the hydraulic computation in the backwater,” Ratte said.

Simmons said he and other city of Boise employees are skeptical about FEMA’s conclusion that the floodplain is so much bigger than the last round of maps showed. Parks that have been developed along the river since then, including Marianne Williams Park and Esther Simplot Park, would absorb river overflow, so they should lower the 100-year flood elevation and therefore shrink the floodplain, Simmons said.

“We’re trying to understand what really changed in the last 10 years in the river that would cause such a change in boundary,” Simmons said. “Because there really haven’t been changes other than, from our perspective, to maybe even improve flood capacity.”


The floodplain is a financial burden for anyone who wants to buy, sell, develop, renovate or insure property in it.

Under federal law, lenders must require flood insurance for any floodplain property bought with a federally backed mortgage, which is most mortgages. The federal government issues these policies, often through private companies that sell and administer the policies, said Deborah Gauthier, FEMA regional senior insurance programs specialist.

The cost of these policies varies based on a variety of factors, including the age of the structure, whether it has a crawl space or on-grade slab, and type of flood zone — there are three for rivers and streams.

Nationwide, Gauthier said, the average cost of a residential flood insurance policy is $700 per year. Estimates are higher in Boise. Tensen, Simmons and Wyllie’s memo put the number at $1,500 per year. Angela Webb, a State Farm insurance broker in Boise, said normal riverside homes, which are more expensive due to location, with four bedrooms and two bathrooms likely would cost between $3,000 and $3,500 per year to insure for flooding.

A worse shock might be in store for people who own homes that weren’t in the floodplain before but are included in new maps. Obviously, the government’s flood insurance requirement can make these homes more difficult to sell.

“It’s tragic to see people who have never paid flood insurance have to start paying it,” Middleton Mayor Darin Taylor said.

There’s more. Before selling, homeowners likely would have to obtain elevation certificates so that insurers can determine the risk of the house flooding. An elevation certificate, which states floor elevations and other relevant information, requires hiring engineers to the tune of $300 to $600, Webb said. This would be the case for most of the homes in the area of Plantation Country Club, said Thornborrow, Garden City’s head of development services.

Furthermore, a home in the floodplain that sustains damage worth 50 percent or more of its value would have to be brought into compliance with the building code, including standards for mitigating flood risk, FEMA spokesman Ryan Ike said. In some cases, that would entail full demolition and reconstruction. The same requirement applies to renovations worth 50 percent of the home’s original value.


One local developer has responded to FEMA’s new floodplain maps with what amounts to a shrug.

Instead of fighting the proposed floodplain boundaries, NeighborWorks Boise, a nonprofit that builds compact affordable housing “pocket neighborhoods,” is designing its new homes with the assumption that the new, larger floodplain is a reality, CEO Bud Compher said.

At three new projects in Garden City, NeighborWorks is building its homes a couple feet higher than normal relative to the ground around them. That should put the bottom floors a foot or so above the level of a 100-year flood, Compher said, avoiding the need for flood insurance.

Raising the houses’ foundations adds cost — about $7,000 to $8,000 per home, Compher said. But the increase to a buyer’s mortgage payment should be less than the price of flood insurance, not to mention the fact that staying above a flood is a good idea whether you have insurance or not.

Compher said he doesn’t know of any other local developers who’ve taken this step to enable their buyers to avoid flood insurance. The trouble at first was that, without sales of comparable houses to reference, lenders might have been reluctant to underwrite the sales of NeighborWorks’ specially built product.

Luck was on NeighborWorks’ side. First, the developer received a few cash offers for completed homes, Compher said, giving subsequent buyers and their lenders those needed comparison points. Second, the Treasure Valley’s housing market has heated up enough that home prices are in line with NeighborWorks prices.

“We ended up creating a bit of our own market,” Compher said.


Early this year, Boise and Garden City hired a team of outside engineers to examine information FEMA used to draw its new floodplain maps.

“Their conclusion was that there were a number of questionable elements in the data that may have exaggerated the projected flood depths and boundaries,” according to the Nov. 10 Boise memo.

On Nov. 15, the City Council authorized Boise to spend up to an additional $25,000 to do some more digging. This time, instead of reviewing FEMA’s work, the engineers will collect their own information. Tensen said they’ll examine newer data than the agency was using; survey a few points along the river channel to see if the measurements FEMA is relying on are accurate; create a two-dimensional model of the river to find out if water realistically can be expected to arrive at some of the low-ground areas in the floodplain map; and analyze vegetation and other features of the river channel and floodplain to determine how flooding would take shape if it occurred.

FEMA will notify Canyon and Ada counties and riverside cities, including Boise, Garden City, Eagle, Star and Middleton, before finalizing the new maps, Ratte said. The agency also will host open houses, likely in late January or early February, to explain the maps and field public comments. The next step would be to open 90-day period during which the public, usually cities or counties, can appeal the maps. That period likely will start in late February or early March, Ratte said.


Boise hopes its research and analysis convinces FEMA to slow down its finalization process. Ideally, Tensen said, the cities and the agency can develop floodplain maps that all sides agree on.

“We don’t know that the maps are wrong at this point,” Boise planning director Hal Simmons said. “All we want to do is make sure that the data is accurate.”

If Boise finds reason to believe FEMA’s maps are wrong, it might appeal them, Tensen said. The cost of the appeal is hard to predict, he said.

“We are roughly estimating this could cost up to $200,000,” according to the city’s Nov. 10 memo. “In this case, we would hope that FEMA would recognize that we are sincere in making sure the maps are as accurate as possible, and would agree to delay formal release of the maps until this issue is resolved.”

FEMA is willing to rework its maps if new information warrants it, said John Graves, branch chief for floodplain management and insurance in the agency’s northwest region offices.

“We want to reflect the risk as accurately as possible on our maps, so we’re going to accept technical data that helps us do that,” he said.

Most of the new floodplain in Garden City, as well as pockets of land in Boise, Parma, Star and unincorporated Canyon County, has been placed in what’s known as “seclusion” due to levees alongside the river, Ratte said. Seclusion means the flood maps won’t take effect immediately because information used to develop them is “subject to further evaluation.”


FEMA employs a typically federal carrot-and-stick method to get cities to adopt its floodplain maps.

Once the maps are finalized, cities must formally adopt them in order to be included in the National Flood Insurance Program, which Congress established in 1968. If a city refuses, it will be suspended from the program, FEMA insurance expert Gauthier said.

If a city is suspended, federally backed flood insurance won’t be available for properties inside its boundaries, making it hard to find financing to buy those properties.

People who own property inside the new floodplain should look at buying flood insurance now, Graves said.

There are two good reasons, he said. First, flood season is coming up, and flood insurance policies take effect 30 days after they’re bought. Second, he said, flood insurance will be cheaper now for homes inside the new floodplain than after the maps are finalized and adopted.

“So they’ll at least get a couple of years of a cheaper policy, called a Preferred Risk Policy, prior to the maps becoming official,” Graves said.