Jefferson Parish, Louisiana
A Louisiana town elevates homes after Hurricane Katrina
In response to the devastation caused by Hurricane Katrina, Jefferson Parish, Louisiana invested nearly $2.4 million in elevating 23 homes. When Hurricane Isaac struck the parish in 2012, none of these homes were flooded, resulting in an estimated $2.2 million in avoided losses. Although the losses avoided were less than the project's costs, the estimate of losses avoided accounts for just one flood event in an area with a history of major storms. It is expected that the losses-avoided ratio will increase significantly over time.
Photo by Mark Wolfe - FEMA
If the 23 homes had not been elevated prior to Hurricane Isaac, each would have flooded above the main-floor level. The properties that would have experienced the highest levels of flooding (up to 3.4 ft) also showed the highest benefit-cost ratios (up to 2.4). The National Flood Insurance Program, and also Jefferson Parish ordinances, require that property owners must elevate homes to the base flood elevation (BFE) or above when building new homes or, if certain criteria are met, when a home is rehabilitated.
The average cost per property of elevating the 23 homes was $102,663. According to a local floodplain management expert, the community's industries, including fisheries and oil production, benefit from the maintenance of a local population, which is possible only if homes are rebuilt, elevated or otherwise made safe from flooding. Mitigation officials highlight that if shrimpers have to live 20 miles from work, they are not able to run their businesses as effectively.
Benefits of mitigation
It is challenging to quantify all the benefits of the parish’s mitigation efforts
The community faced challenges in demonstrating positive benefit-cost ratios (BCRs) for some projects, owing to the difficulty of quantifying other gains, such as environmental and social benefits. It is often challenging to demonstrate the additional benefits (other than avoiding damage to buildings) from, for example, building a levee around a small town, but those benefits nevertheless exist.
Such additional benefits include growth in local industry, the maintenance of a local population and local businesses to support that population, and the presence of facilities for tourists, such as hotels and restaurants.
“If you just keep haphazardly going around doing one project that doesn't feed into the next, you may be hurting yourself in the end”
"Having a long-term flood mitigation strategy will help to protect the community and its citizens against future storms," says Michelle Gonzales
The number of flood claims in Jefferson Parish has declined significantly since 2005, and the community is starting to realize the benefits of drainage upgrades, home elevations and other mitigation projects. The parish is now seeing improvements in the buyers’ market and in property values, thanks in part to these efforts. “These projects have brought a lot of value to our community,” says Michelle Gonzalez, director of floodplain management and hazard mitigation for Jefferson Parish.
Additional flood mitigation efforts will continue in the community, based in large part on a state mitigation master plan for the coast. However, in the short term, such projects may struggle to gain state funding, due to weaker revenue from the local oil industry on the back of lower global oil prices.
Flood-prone neighborhood is converted into a park
Riverine flooding, Flash flooding