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Eden Isle Flood Risk Reduction

Background

Eden Isle, Louisiana, an access community on the northern rim of Lake Pontchartrain, is vulnerable to coastal flooding, especially during storm surge events. To address this, CPRA conducted a feasibility study outlining key structural needs for the area and shared the findings with the St. Tammany Levee, Drainage and Conservation District (STLDCD) and the St. Tammany Parish Government in June 2026. The feasibility study proposes risk reduction solutions for three critical project areas: Grand Lagoon, Harbor Drive, and Lakeview Drive.

For each project area, the study provides alternatives for flood risk reduction. The alternatives were proposed to ensure that the locals of Eden Isle and leaders in St. Tammany Parish can collectively agree on which kind of project is best for the given area.

CPRA is committed to providing +11 ft risk reduction to the Eden Isle Community in conjunction with the following requirements:

  1. St. Tammany Parish government and STLDCD mutually agree on preferred alternatives and present to CPRA
  2. St. Tammany Parish must develop a revenue plan to fund construction and long-term operation and maintenance of the desired alternative structure
  3. Engage DOTD to raise Hwy. 11 to at least +11 ft. risk reduction

Grand Lagoon

CPRA recommended a floodgate be constructed at the entrance to Grand Lagoon, which sits between Lakeview Drive and Harbor Drive. A floodgate would provide +11.0 ft risk reduction, and the feasibility study recommended that a barge gate would be most appropriate for the project area. There are two viable alternatives for floodgate protection levels.

Alternative A: +40 ft Protection

  • Easier to construct, less costly
  • Estimated Cost: $36M

Alternative B: +90 ft Protection

  • Easier to operate, gives more time to close
  • Estimated Cost: $43M

 

Harbor Drive

The feasibility study proposed three alternatives to the westernmost segment of Harbor Drive, a portion of the road comprised of vacant lots and not home to residential properties. Each alternative ensures protection up to + 11 ft.

Alternative A: Elevating Harbor Drive

  • Raises Harbor Drive in its current location to the target protection level of +11 ft.
  • Estimated Cost: $4M – $8.7M

Alternative B: Earthen Levee

  • Constructs an earthen levee south of Harbor Drive, allowing for minimal roadway impacts and flood risk reduction to Harbor Drive.
  • Estimated Cost: $1M – $9M

Alternative C: Replace Existing Bulkhead

  • Requires full reconstruction of the existing bulkhead, using the shoreline alignment to provide the highest alternative level of protection of +12 ft.
  • Estimated Cost: $19.6M

Lakeview Drive

The southern point of Eden Isle is Lakeview Drive, a stretch spanning ~250 parcels. While this segment provides challenges to constructing risk reduction structures, it is essential that Lakeview Drive be better protected as it borders Lake Pontchartrain. Four alternatives were proposed in the feasibility study, all providing up to +11 ft of protection for the community.

Alternative A: 2-Lane Road

Raises Lakeview Drive in place as a two-lane roadway with one lane on each side of a centerline barrier. Construction would be completed in two phases and may require utility relocation and a steeper incline for driveways. Phase 1 would elevate the roadway to +8.5 ft, and Phase 2 would install a centerline floodwall to reach +11.0 ft.

  • Land Acquisition: Minimal – driveway acquisition
  • Utility Relocation: Yes
  • Traffic Impacts: Significant – Roadway size and wall limit normal traffic function; requires turnaround installations
  • Homeowner Impacts: Moderate – Steep incline required for driveways; minor impact to lakefront view (2.5′ wall)
  • Estimated Cost: $43M-54M

 

Alternative B: 4-Lane Road

Raises Lakeview Drive to +6.0 ft as a four-lane divided roadway with two travel lanes on each side of a centerline barrier to reach +11.0 ft. Construction may require utility relocation and the acquisition of residential driveway space.

  • Land Acquisition: Partial – driveway acquisition
  • Utility Relocation: Yes
  • Traffic Impacts: Moderate – Two lanes on either side of the floodwall allow more normal traffic flow
  • Homeowner Impacts: Significant – Limited space between homes and roadway; Limits lakefront view (5’ wall)
  • Estimated Cost: $63M-$69M

Alternative C: Floodbreak

Raises Lakeview Drive in place as a two-lane roadway with automated risk reduction. Construction would be completed in two phases, where Phase 1 would elevate the roadway to +8.0 ft and Phase 2 would install self-deploying flood barriers to reach +11.0 ft.

  • Land Acquisition: Partial – driveway acquisition
  • Utility Relocation: Yes
  • Traffic Impacts: Minimal – Traffic will be able to cross the floodwall when retracted
  • Homeowner Impacts: Minimal – Steep incline required for driveways
  • Estimated Cost: $143M

Alternative D: Earthen Levee

Constructs a continuous earthen levee north of Lakeview Drive in lieu of roadway elevation to reach +11.0 ft of protection. Alternative D would require the acquisition of properties and homes north of Lakeview Drive.  The existing roadway would be unaffected. Alternative D Option 1 requires acquisition of properties north of Northshore Circle; Alternative D Option 2 requires acquisition of properties south of Northshore Circle.

  • Land Acquisition: Significant – all homes/properties north of Lakeview Drive + north or south of Northshore Circle depending on final alignment
  • Utility Relocation: Minimal
  • Traffic Impacts: None – Does not affect existing roadway
  • Homeowner Impacts: Significant – Buyout required for all homes north of Lakeview Drive + north or south of Northshore Circle depending on final alignment
  • Estimated Cost: $58M-$59M

 

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