Why did River Bluff flood?

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An aerial shot of River Bluff subdivision in north Bossier. (photo by Tom Pace)

Despite its proximity to the Red River, requirements to build homes in the River Bluff subdivision were met.

According to Bossier Parish Attorney Patrick Jackson, all governmental approvals were sought and obtained to build the subdivision, including permission from the Bossier Levee District and the Red River Valley Association. A flood of historic proportion, though, has the neighborhood of luxury homes surrounded by several feet of water, bringing its location across the levee into question.

Since the requirements were met at the local, state and national level, Jackson explained it as a “buyer beware” situation.

“There’s a parallel set of laws coming into River Bluff,” Jackson explained. “Under the law, if someone has a piece of property that meets all the requirements, you have to let them do what they want to do or you buy it from them. If we tell them no, we have condemned the property.”

River Bluff, which is located on Benton Road just north of I-220, is said to be “Bossier’s premiere riverfront sanctuary.” Shreveport Real Estate, LLC describes the subdivision as one that offers a “unique luxury living experience.” The gated community, built just over the levee that stretches along the Red River, gives residents “the opportunity to have the best access to everything it has to offer.”

In a subdivision not located on a river, Jackson said the way it works is a builder goes to an engineer to make sure the piece of property is adequately zoned for a residential development. The engineer then studies the land and draws up a plat, or map, with the streets, drainage and subdivision lines for lots drawn out.

Part of that process includes looking at land elevation to report to the Federal Emergency Management Agency (FEMA) Flood Map Service Center, the official public source for flood hazard information produced in support of the National Flood Insurance Program (NFIP). For every parish in Louisiana, FEMA produces flood maps and sets forward the elevation at which someone must build in order to participate in the NFIP. This is referred to as base flood elevation (BFE), a computed elevation to which floodwater is anticipated to rise during the base flood. The BFE is a regulatory requirement by FEMA for the elevation or floodproofing of structures.

Not all properties have a BFE number and must be acquired through a study by the U.S. Army Corps. of Engineers.

Jackson said Bossier Parish goes a step above what the governmental agencies require when it comes to building homes based on the base flood elevation.

“As a part of the parish or city requirement, FEMA gives us ordinances to pass in order for our citizens in our parish to participate in the NFIP,” he explained. “They say, we must not allow any development in any area without a BFE. The parish adopts ordinances that say you must get a BFE from the corp to put on a FEMA map, but we require that homeowners build to that BFE plus one foot. If you write to the corp and they said the BFE is 127 feet, you would actually have to build at 128 feet in Bossier Parish.”

Jackson said they had “a number of citizens” come in and say it was a bad idea to build on the river banks and that they should not be allowed to build there.

“The problem is, if they meet all the requirements it’s basically a ‘buyer beware’ situation,” Jackson said.

One problem they did encounter was the location of River Bluff did not have a base flood elevation. Steps were taken to acquire one, but Jackson said they realize that number was not accurate.

The big question now is: how did the National Weather Service miss the river flood stage so badly?

“We haven’t had this kind of flood since 1945. The bottom line is that this is the only technical aspect of the process that really deserves serious critique,” Jackson said.

The National Weather Service changed the river crest prediction seven times between May 24 and June 7. Predictions went from a 31.5-foot crest on May 24 to a 34-foot crest on May 29, followed by an expected crest of 35.5-feet on June 4 then an additional foot on June 5.

The final crest prediction reached 37-feet on June 7.

“At 29 feet, River Bluff is totally fine. At 33 feet, River Bluff is pretty much ok. Then it went to 37 feet. How can, with no additional rain, the numbers be off that much,” Jackson asked.

Jackson began explaining the following theory on what might have gone wrong.

The Army Corps of Engineers conducts surveys of the river to establish the channel of the river and to know how wide and how deep the river is in order to determine how much water the river can carry.

Jackson reports the last study conducted on the river was done more than two decades ago and doesn’t account for the silt and sediment that has accumulated at the bottom of the river over time.

“When they put in the locks and dams, it stopped the water, causing the silt and sediment to settle way up north instead of a rushing stream carrying that silt down to the Mississippi,” Jackson explained. “All the modeling they were doing 25 years ago was based on an empty channel. That’s why the predictions were wrong. The same amount of water was coming through, but they didn’t account for the amount of build up at the bottom of the river.”

Jackson said that is the key component to understanding the historic flood of 2015.

“There has not been any money assigned by the Corps of Engineers to conduct a new study because all the money is used to keep the river navigable,” Jackson said. “Everything north of lock and damn #5…no one really cared about until we had a flood.”

His theory is that the lack of updated figures and studies on the river is what turned this flood into a catastrophic loss for several homeowners in River Bluff.

“It wasn’t our local guys. They were using the models and tables provided to them,” Jackson said. “The assumptions were bad because of the build up in the river. Had they initially said the river would crest at 37 feet, we would’ve seen property owners in River Bluff taking more protective measures around their houses.”