When the fish lift at the U.S. Army Corps of Engineers, Charleston District’s St. Stephen Powerhouse and Dam started experiencing hydraulic failure last spring, Brian Wells, chief, operations division, knew it was time for a thorough inspection.
“When gate one failed to open in March, we decided to de-water the fish lift for the first time in 27 years to see what work needed to be done,” said Wells. “After it was de-watered, it was evident that a total renovation was going to be required as the crowder gates, the grating at the bottom of the crowder chamber and a stainless steel drain valve were completely rusted.”
The District worked quickly to get the $2 million contract awarded for the design and renovation. Lindbergh and Associates was awarded the contract for design work and Kaiser Kane, Inc. was awarded oversight of the construction. The renovation started in July 2012 and will be completed just in time for the fish migration season in February 2013.
Some of the major renovations completed included replacing the grating on the bottom of the crowder chamber, the entire hydraulic system, a new HVAC system in the hydraulic room, and three vertical bulkheads. Additionally, new safety features were installed and an updated annual maintenance plan was developed for the facility. The most challenging replacements because of their size were two 25 feet, 8,000 pound gates and a 30 inch stainless steel drain valve that was custom fabricated. All of these replacements will ensure that the fish lift is running efficiently and passing fish as it should for many years to come.
Passing the fish is not only important to the spawning process, but also provides an ocean nutrient food source for freshwater fish such as the Landlocked Stripe Bass, which attracts anglers come from all over to fish at Lakes Moultrie and Marion. The fishing industry has a big impact on the South Carolina economy; in 2011 freshwater fishing brought approximately $1.8 billion to the state.
These renovations to the fish lift are crucial to the survival of the approximately 600,000 anadromous fish that the St. Stephen fish lift passes every year from February 1st to May 1st. The fish anxiously wait for the facility to open where they swim into the crowder area and are coaxed into the lift chamber by the crowder gates. From there the lift floods with water from the reservoir above and a large basket lifts the fish up 70 feet to the reservoir level. The fish are prompted to swim up and out of the lift through the fish viewing passage and they exit through the lakes systems where they travel upstream to spawn. SCDNR biologists have cameras mounted in the viewing windows and underwater in the passage chamber, so fish can be identified and counted. This information allows biologists to estimate population sizes of the various species of migrating fish.
“Another aspect of the renovation is the visitor’s experience. Thousands of visitors come to see the only fish lift in the Southeastern region and to see one of nature’s true wonders – thousands of fish passing through the fish lift on their spawning migrations. The viewing room was very drab and unwelcoming. We are hopeful that the upgrades will provide a great experience for the citizens of South Carolina and other visitors, and influence the next generation of conservation-minded citizens,” said Joe Moran, project manager of the St. Stephen fish lift renovation and fishery biologist.
Currently, the viewing room is cold tile and sterile walls, but after the renovation, the room will be transformed to look like a dock and lake. The floors will be replaced with a vinyl composition tile that looks like a wooden plank to mimic a dock, rough-cut cypress wainscoting will be added to the walls to enhance the dock feeling and fish appliqués will be placed on the newly painted blue walls to give the impression of being ‘crowded’ into the passage chamber just like the fish. To add to the experience, a new large flat screen television will show two new videos; one is from the fish’s perspective as it enters, travels and exits through the fish lift system and the other is the history of the Cooper River Rediversion Project (CRRP).
To further enhance the visitor’s experience, a pavilion will be added near the South Carolina Department of Natural Resources’ (SCDNR) Bayless Fish Hatchery where people can enjoy lunch or sit out on a beautiful, sunny day.
The fish lift is just a small component of the CRRP and St. Stephen Dam. The CRRP was constructed to reduce the sedimentation in the Charleston Harbor which had become an issue when the Santee River was dammed in 1941 to provide power to South Carolina residents. The Dam also caused the flow rate into the Cooper River to increase from 100 cubic feet per second (cfs) to 15,600 cfs. This resulted in the sedimentation rates from the Cooper River into Charleston Harbor to increase from 500,000 cubic yards per year (cy/yr) to 10 million cy/yr, which also increased the dredging costs. Since the Rediversion canal and the St. Stephen Dam became operational in 1985, sedimentation rates in Charleston Harbor have decreased to two million cy/yr and saves the taxpayers $14-$18 million per year in annual dredging costs. Since the dam also prevented migrating fish from getting to their spawning areas, the fish lift was built.
Another aspect of the CRRP is the St. Stephen Powerhouse which provides enough power to supply energy to approximately 40,000 homes in the Santee Cooper power grid. The rediversion canal brings water from Lake Moultrie through the powerhouse where it goes through one of three fixed-blade 28 kilowatts generators. The turbine is rotated by the forces of water, the turbine in turn rotates a generator, and the generator produces electrical power which is then converted and transmitted to the electrical power grid.
The fish lift, the dam and powerhouse all provide very different and important benefits to the state of South Carolina and the nation. The Charleston District looks forward to passing fish this season in the renovated fish lift. The fish lift is open to the public from March 15th- April 15th, if you would like to make a reservation to watch the fish pass, please call SCDNR at 843-825-3387.