Santa Rosa County, Florida

New drainage system frees Florida community from pond overflows

Navarre, a community in Santa Rosa County, was built around the edges of Orion Lake, a pond that serves as a detention basin linked to a nearby wetland. The pond’s inadequate drainage system caused it to overflow during heavy rain events, damaging homes and blocking public roadways. In 2005, Navarre used FEMA grants to expand the outflow pipes in the pond to move stormwater more rapidly into nearby wetlands. In April 2014, between 12 and 20 inches of rain fell in the county in a single morning, causing flash flooding and millions of dollars of damage to area infrastructure and homes—except for the 216 properties around Orion Lake.

Community facts

Population
163,903
Homes
67,603
Businesses
10,584
Source: US Census Bureau.

Mitigation actions

After meeting the necessary Hazard Mitigation Grant Program requirements with its mitigation plan, Santa Rosa County secured a $682,000 FEMA grant in 2005 to expand an inadequate drainage system on Orion Lake, which had resulted in frequent flooding to adjacent homes. The project was completed in 2011. In 2012 and 2014, Navarre experienced two heavy rain events. Thanks to the upgraded system, the community avoided $1.6 million in losses and damages. Additional loss avoidance benefits are expected from future events.

The 2014 storm was a 0.2-percent annual chance flood event, causing 20–22 inches of rain to fall in Navarre—yet none of the homes along Orion Lake flooded. “The water can now bleed off the lake faster than the storms can replace it,” says Michael Schmidt, assistant county engineer.

Benefits of mitigation

Economic benefits
$1.62 million
Total monetized benefits
Return on investment
138.0%
Estimated return on investment
Benefit-cost ratio
2.38
Benefit-cost ratio of the Santa Rosa project
Source: Florida State Emergency Response Team (2014). Loss Avoidance Assessment: Florida Severe Storms, Tornadoes, Straight-line Winds, and Flooding April 28th to May 6th, 2014.

Project challenges

Five years to finish

Project funding was approved in 2006, but construction was not completed until 2011, partly owing to extensive permit reviews. The county was also dealing with other water infrastructure needs and flooding events during this time, which limited the resources they could invest in pushing the project forward. The community supported the project, even when construction crews tore up some homeowners’ yards to install the new drainage system. “They knew the outcome would be worth it,” Schmidt says.

“Since the drainage systems were put in place, the subdivision has not had any problem with flooding”
Michael Schmidt, assistant county engineer Santa Rosa County, Florida

Future considerations

Flooded pier from coastal waters.
FEMA grants help Santa Rosa stretch its resources to address flooding problems across the county

This drainage program was just one of a series of high-priority projects under a comprehensive hazard mitigation plan that addressed the county’s overall flood risk needs. Between 2005 and 2011, Santa Rosa County also secured FEMA grants to support several additional flood mitigation projects, all of which were successfully completed and are now delivering benefits to the community. Since then, the county has continued to plan and has secured FEMA grants for five more projects to regrade detention ponds, add stormwater detention facilities and update storm sewer systems.

Flood mitigation resources

Below is a non-exhaustive list of other flood mitigation information resources.