The past year saw both low water and high water at Lake Okeechobee, as well as completion of one project and the start of others on Herbert Hoover Dike (HHD).
The best news occurred in October, when the last section of cutoff wall in the dike between Port Mayaca and Belle Glade was accepted by Jacksonville District construction representatives. The action meant 21.4 miles of cutoff wall that had been under construction since 2007 was in place, reducing the risk of failure for the southeast portion of the dike.
The focus of repair activity at the dike is now replacement and removal of water control structures, also known as culverts. Beginning in the 1930s, 32 structures were installed and are now seen as the greatest risk to continued stability of the dike. Jacksonville District removed Culvert 14 south of Port Mayaca in the spring. Two replacement projects began in January – one at Culverts 1/1A between Clewiston and Moore Haven; the other at Culverts 11/16. Work on the replacement projects is expected to continue through 2015.
In September, the district awarded another contract for replacement of Culverts 3/4A between Clewiston and South Bay. Work on that project is expected to begin shortly. Contracts are expected to be awarded in early 2013 for the abandonment of three additional culverts near the city of Okeechobee on the north side of the lake. The district is expected to award contracts for the replacement of six other water control structures later in the year.
In early June, the district hosted 27 students from 20 countries in Africa, Asia, Europe and South America as they toured HHD and learned about the repair work. The visit was part of a trip for students enrolled in the United Nations Educational, Scientific, and Cultural Organization’s (UNESCO’s) Institute for Water Education. The students were candidates for a Master of Science degree in Hydro-informatics, a program that uses modeling and information technology to help solve hydraulic and other water-based environmental problems.
While construction continues, Engineering Division continues to conduct analyses aimed at guiding the future direction of repairs to the dike. These analyses will be used as the basis for a Dam Safety Modification Study (DSMS), which is expected to be finalized in 2014. Information in the DSMR is expected to guide development of the next round of HHD projects. The ultimate goal is to improve the dike’s Dam Safety Action Classification (DSAC), which currently classifies the dike as a structure with very high risk in need of repair. Due to the amount of work needed, it may be a full decade before work is finished.
For water managers at Lake Okeechobee, 2012 was a year filled with typical challenges of not having enough water, then suddenly being in a position of having too much water.
For much of the first half of the year, the lake’s water level dwindled as water was supplied for various uses around the lake, including crop irrigation. A series of water releases was made to the Caloosahatchee Estuary to help offset rising salinity, but those releases had to be suspended when the lake dropped below the lower end of its preferred minimum of 12.5 feet. The summer started off with steady rains, but it wasn’t enough to cause a noticeable rise in the lake…until the end of August and Tropical Storm Isaac.
Isaac passed over the Florida Keys Aug. 26 and made its way into the Gulf of Mexico. Heavy rain associated with Isaac worked its way up the Atlantic coast, dumping more than 15 inches of rain in Palm Beach County, and more than eight inches on Lake Okeechobee. This caused various streams and canals that drain into the lake to fill up as well. Within two weeks, Lake Okeechobee had risen nearly three feet, and the district began discharging water from the lake Sept. 19. Two weeks later, the district increased the releases to 4,000 cubic feet per second (cfs) at the Moore Haven Lock and 1,800 cfs at the St. Lucie Lock. In early November, as the lake water level started to decline again, the releases were suspended to the St. Lucie Estuary, but were continued for environmental reasons in the Caloosahatchee.
The decision on water releases was guided by the 2008 Lake Okeechobee Regulation Schedule (LORS). LORS was the result of a multi-year study on water management that included significant input from the public. It was developed to balance the performance of multiple project purposes while preserving public health and safety. Everything is considered, including but not limited to historical lake levels, current weather conditions and forecasts, hydrologic outlooks, estuary conditions and needs, lake ecology conditions and needs and levels in water conservation areas.
One of the authorized uses of water in Lake Okeechobee is to maintain suitable levels in the canals and streams that form the Okeechobee Waterway, which runs from the Atlantic Ocean at Stuart to the Gulf of Mexico at Fort Myers. The district operates five navigational locks along the waterway. Business continues to be brisk, and the district undertook multiple projects to keep the locks fully functional.
At Moore Haven, the lock was closed during the early summer for installation of manatee protection system (MPS) equipment. The MPS equipment protects manatees in the vicinity of the locks from being caught in a closing gate. Upon completion of the MPS installation at Moore Haven, all five locks in the Okeechobee Waterway are now equipped with the protective devices.
In addition to the repairs at Moore Haven, the district closed St. Lucie Lock in late June to conduct emergency repairs on a faulty seal that was preventing full closure of the gates. Both locks were operational by mid-July.
To standardize the operations of Corps locks across the nation, the district reduced the operating hours for the locks Nov. 13. The locks are now open 12 hours daily, from 7 a.m. to 7 p.m. Under this nationwide plan, operations will be reviewed annually at each lock, and hours will be adjusted based on the lockage activity.
Another busy year is in store in 2013. Additional contracts for replacement of water control structures are expected to be awarded. Water managers will continue to strive for balance in meeting the environmental needs of the estuaries, while ensuring adequate storage is available in Lake Okeechobee for the next hurricane season, which starts June 1.