#05-212 October 10, 2005
Construction of Fish Passage to Temporarily Disrupt Broad River Flow
Work to construct a new fish passage facility at the Columbia Lock and Dam on the Broad River will cause temporary interruptions in the continuous flows now released at the diversion dam. The facility is scheduled for completion in 2006.
"Continuous flows to the by-passed river are needed to provide adequate spawning and/or maturation habitat for a variety of fish and aquatic organisms," said Dick Christie, Federal Energy Regulatory Commission coordinator for the S.C. Department of Natural Resources (DNR). The S.C. Water Resources Commission, now a part of the DNR, recommended that flows of 550 cfs to 900 cfs seasonally be established. These recommendations were based on site-specific studies conducted in 1988-1992.
"In spite of old equipment and highly variable flows, South Carolina Electric & Gas personnel have been doing a great job in providing those flows by maintaining the reservoir level 4 to 5 inches above the top of the diversion dam," Christie said. "Unfortunately, it will be necessary to occasionally disrupt those flows, on a temporary basis only, to complete the construction of the fish passage facility."
The Columbia Canal, which was begun in 1819 by the State of South Carolina to provide barge traffic, now provides electricity for South Carolina Electric and Gas (SCE&G). Flows from the Broad River are diverted into the three-mile long canal, where they power three generators that produce a total of about 11 megawatts. The Canal diverts up to 6,000 cfs (cubic feet per second) of water from the main river channel.
In 2002, the Federal Energy Regulatory Commission issued the current operating license. The new license required, among other things, that continuous flows and fish passage be provided.
Another condition of the new licenses is providing safe and effective upstream and downstream fish passage. The Columbia Dam has blocked the migrations of several commercially important fish species from reaching their historic spawning grounds.
"We have an excellent opportunity to restore shad, herring and other important fisheries to the Broad River basin," said Press Brownell with the National Marine Fisheries Service. "Our initial target species for passage include American shad, blueback herring and American eel. We also hope to see some sturgeon passing to their historical spawning areas upstream." Shad and herring migrate from the Santee to the North Atlantic Ocean, where they are important food for many ocean species like tunas, mackerel, and red drum.
According to Amanda Hill of the U.S. Fish and Wildlife Service, the passage facility will be a vertical slot ladder. "A fish ladder is a structure designed to allow fish the opportunity to migrate upstream and continue their function as part of the river ecosystem," Hill said. "A fish ladder enables fish to pass around a barrier by swimming up a series of relatively low steps into the waters on the other side. The velocity of water falling over the steps has to be high enough to attract the fish to the ladder, but it cannot be so great as to wash fish back downstream or to exhaust them to the point where they cannot continue their journey upriver."
Construction on the facility has begun, and it is scheduled for completion by March 2006. The facility will be operational for the spring 2006 migrations, effectively passing migratory fish upstream of the Columbia Dam.
"This fish passage facility will be the first non-federal passage facility in South Carolina," said Hill, "a remarkable achievement of the federal and state natural resource agencies and SCE&G toward the restoration of anadromous fish in the Santee Basin."