The U.S. Army Corps of Engineers is monitoring two sites along the aging Herbert Hoover Dike in Palm Beach County, where inspectors have discovered water seeping under pressure from the high level of Lake Okeechobee.
One site, near the 21-mile cutoff wall that the Corps recently completed between Pahokee and Belle Glade, was first detected two years ago. However, the amount of water seeping has increased from 2-gallons per minute to 2.5 gallons-per-minute, according to Lt. Col. Thomas Greco, the Corps deputy commander of south Florida.
A new seepage site was discovered Tuesday in a ditch at the foot of the dike between Belle Glade and Clewiston, Greco said. The Corps does not release specific locations, for homeland security reasons.
Greco said “seepage is normal” and inspectors have not seen any dirt or sediment being pulled out by the seepage. If that were to happen, the Corps would act immediately, Greco said. The Corps uses a four-point scale to rank conditions along the dike. Condition 1 — the least problematic — is assigned to wet spots where the soil is saturated. There are between 13 to 15 Condition 1 sites along the dike, all discovered before the lake’s level began rising rapidly in June and July, Greco said.
There are no Condition 2 sites, where calm, standing water is observed. Both seepage sites being monitored are Condition 3 sites, where there’s seepage but no sediment dislodged, Greco said.
There are no Condition 4 sites, where seeping water pulls soil and sediment from the dike, Greco said.
Weekly inspections of the 143-mile dike began two weeks ago and the Corps will conduct daily inspections if the lake hits 16.5 feet. As of Wednesday, the level was just under 16 feet.
In addition to the inspections, the Corps has activated the emergency operations center at its Jacksonville headquarters. The Corps also conducted a conference call with local emergency managers to update them on the condition of the dike and efforts to lower water levels.
“The key concern we focus on is dike stability as we go through these high-level times,” Greco said.
The good news is that there is finally more water flowing out of the lake than into it — a benchmark that has not been seen in recent weeks despite the Corps’ decision to fully open locks along the St. Lucie Estuary and Caloosahatchee River. Several sunny, rainless days have halted the relentless rise of water and actually caused a very small decrease in the lake’s level.
Still, the releases to the estuaries will continue until the lake drops below 15.5 feet, Greco said. And that could be at least through the end of the year, as the wettest and most hurricane-prone months lie ahead.