Dike inspectors receive dam safety training at Jacksonville District US Army Corps of Engineers
June 21, 2010
- The dam safety training provided what to look for on a dike: seepage, cracking, instability, sinkholes and depressions.
- The structure experiences internal erosion known as "piping" that can result in water seeping through to the other side.
- The level of Lake Okeechobee was 2 feet higher than desired at the beginning of the 2010 hurricane season.
The people entrusted to monitor the Herbert Hoover Dike received a refresher course in dam safety. The training was offered May 25 to 27 at the South Florida Operations Office of the U.S. Army Corps of Engineers, Jacksonville District in Clewiston, Florida. Approximately 55 employees of the Corps of Engineers and South Florida Water Management District participated.
The more than 75 year old earthen Herbert Hoover Dike can leak at its base during periods of high water levels. The structure experiences internal erosion known as "piping" that can result in water seeping through to the other side. There is no concern of lake water overtopping the dike; it is seepage at the base that is a concern. The dike is undergoing a major rehabilitation project over many years to strengthen it.
The level of Lake Okeechobee was 2 feet higher than desired at the beginning of the 2010 hurricane season. This is due to a very "wet" dry season, with above-normal rain in the winter and spring. The Corps has been discharging water from the lake since March to lower its level.
Dike inspectors are part of a larger team to watch for signs of concern on the dike - to catch any possible seeping or other issue at an early stage, if possible. The Corps monitors the dike on a routine basis throughout the year (and more as needed for special circumstances), but steps up the inspections to daily once the water level reaches 16.5 feet.
The dam safety training provided an overview of the stressors to look for on the Herbert Hoover Dike: seepage, cracking, instability, sinkholes and depressions, and other maintenance concerns. The indicators are caused by a variety of reasons and can signal a weak spot in the dike in need of repair. The training also covered safety, documentation, and reporting incidents of concern.
"The goal is to instruct equipment operators, park rangers, and the person mowing the grass that everyone has a responsibility for dam safety," said Brent Trauger, Corps Dam Safety Program manager. "Their trained eyes have an important role."
Classroom instruction was offered in the morning. This covered the features of the Herbert Hoover Dike, conducting inspections of the embankments, documenting and reporting findings from safety inspections, and the Emergency Action Plan for the Herbert Hoover Dike. Participants went on a site visit in the afternoon to a section of the southeast dike where a small boil had developed at the base of the dike. Calvin Grinslade, Corps primary inspector, led this session.
In addition to the 55 dike inspectors, more than 200 Corps employees stationed in Jacksonville, Florida, are on response teams that immediately deploy following a storm or high water event. The South Florida Water Management District works in partnership with the Corps to operate the regional water management system, and will provide staff too. The Corps and water management district both coordinate closely with county and city governments as well.
For more information, please visit www.saj.usace.army.mil, and click on Herbert Hoover Dike and Lake Okeechobee.