SOUTH BAY — The U.S. Army Corps of Engineers Jacksonville District presented an update on the Herbert Hoover Dike repairs at the Sept. 1 South Bay Commission Meeting.
The Herbert Hoover Dike, which was first authorized to be built in 1930 after a series of disastrous hurricanes in 1926 and 1928, was built using hydraulic dredge and fill methods. Those methods are not acceptable by today’s construction standards.
The 143 miles of embankment around Lake Okeechobee include 32 federal culverts, five spillway inlets, five spillway outlets, nine navigational locks and nine pump stations.
Since its initial construction, the dike has experienced failures in the form of internal erosion (seepage) through its embankment and foundation; soil erosion into and around the culverts; and overwashing that led to erosion of the downstream slope around the dike.
In 2006, the Herbert Hoover Dike was assigned a Level 1 Dam Safety Action Classification by the Corps. Level 1 means the dam was unsafe, and critically near failure, according to the Corps’ rating table.
The area of embankment between Port Mayaca and Lake Harbor, which includes Pahokee, Canal Point, Belle Glade and South Bay, was deemed the most at-risk zone by the Corps. The area between Lake Harbor and Lakeport, which includes Clewiston and Moore Haven, was deemed the second most at-risk zone.
The Corps initiated three major solutions to rehabilitate the dike, including constructing cut-off walls under the Major Rehabilitation Report (MRR) of 2000; replacing or removing 29 of the 32 federal culverts under the Federal Water Control Structure Culverts of 2011; and, implementing a Dam Safety Modification Study to be completed by 2016.
As part of the MRR, the Corps installed 21.4 miles of cutoff wall between Port Mayaca and South Bay from 2007 to 2013.
The Corps still plans to install cutoff wall tie-ins (gap closures) to three existing structures near South Bay, Belle Glade and Pahokee, as well as one bridge near Port Mayaca. That contract is expected to be awarded in fiscal year 2016.
The Corps also plans to install 6.6 miles of cutoff wall between South Bay and Lake Harbor to be completed by 2020.
Other U.S. Army Corps of Engineers projects in the Glades area include an ongoing construction contract to replace three culverts between Pahokee and Belle Glade.
Corps officials said these projects will reduce risks of dike failure to the Glades-area communities.
Once these projects are completed, the Corps could allow recommendation for accreditation to FEMA (Federal Emergency Management Agency). Because the dike is subject to failures, FEMA cannot certify the dike to prevent a 100-year flood — a condition that affects the newly mandated flood insurance policies.