Out past the stone parapets that frame the gateway to Augusta's historic canal, the Savannah River cascades across an ancient, concrete wall.
That linear barrier, erected 158 years ago, forms one of the river's oldest and most important dams, according to Ed Bettross, a Georgia Wildlife Resources fisheries biologist.
"The Augusta Diversion Dam is just above the last remaining stretch of rocky shoals in the entire river," he told members of the CSRA Flyfishing Association last week.
During the past 60 years, 156,000 acres were flooded upstream to build lakes Hartwell, Russell and Thurmond. As other shoals vanished, the whitewater near Augusta became the lone remnant of a vital ecosystem.
Those shoals, home to myriad unusual fish and plants, are among the river's least accessible areas, he said, and face undue hardship because of erratic fluctuations in river flow.
Soon, however, that situation could change.
Bettross and members of a dozen state and federal agencies are involved in a complex series of studies associated with relicensing the Augusta Canal through the Federal Energy Regulatory Commission.
Although the licensing process is ponderous and costly, the end result could create better fishing opportunities and more fish in the shoals.
The long-term goal, he said, is to restore large numbers of species, such as striped bass, sturgeon and American shad to the shoals, and to improve populations of redeye bass and other shoal-dwelling sportfish.
The key to that plan involves fish passage structures - first at New Savannah Bluff Lock & Dam many miles downstream near Augusta Regional Airport.
A planned renovation at New Savannah Bluff includes a $4.8 million series of artificial pools that will allow migrating fish to swim upstream - past Augusta - to the shoals.
Efforts also are under way to establish fish passage at the Augusta Diversion Dam and Stevens Creek Dam, a small hydropower project two miles farther upstream.
The Diversion Dam was built in 1845 and expanded in 1874 under the guidance of engineer Byron Holley. His objective for the dam was simply to divert water from the river into Augusta Canal.
Although a concrete "fish ladder" was erected midway across the dam, today's scientists - Bettross included - doubt fish can use it. "We're not sure it ever worked, but it certainly doesn't work today."
Neither the Augusta Diversion Dam nor Stevens Creek - owned by South Carolina Electric & Gas Co. - has adequate fish passage structures, and both dams need them, according to the Federal Energy Regulatory Commission, which licenses hydropower projects.
The Diversion Dam's 50-year license, issued in 1929, expired in 1979. Since then, the city has operated its canal without a license and is under pressure from the federal government to renew.
Failure to secure a license could allow private companies to file for custody of the canal to exploit its water power for commercial purposes. Augusta officials don't plan to let that happen.
The regulatory commission, however, is likely to require environmental improvements - including a fish passage device - as a condition for relicensing, Bettross said.
"We have a dam that goes across a river and diverts a lot of water into a canal that passes some very important shoals," he said. "There is a lot to be considered."
Although a fish passage device would be costly, it would trigger a requirement for the owners of Stevens Creek dam upstream to build a comparable structure, he said.
Then, sportfish such as striped bass could migrate all the way to the base of Thurmond Dam, and many more miles of river would be opened for spawning of important species.
The regulatory commission relicensed Stevens Creek Dam in the mid-1990s - and wrote in a requirement for a fish ladder. The dam's owners were allowed to postpone that project until fish passage was created downstream.
"We'd like to see the two projects done simultaneously, or near simultaneously," Bettross said.
Several possible designs are under consideration for a fish passage at the Augusta Diversion Dam, but long-term decisions will depend on feasibility and funding.
One possibility is to incorporate the idled canal locks into a new fish passage area. There could even be an observation window below the water level to enable visitors to watch fish moving upstream.
Other options include a simple, improved version of the existing fish ladder, he said.
Changes also are under way regarding flow in the river - a perennial problem in drought years when the shoals have virtually dried up.
Georgia's Department of Natural Resources wants the city to guarantee minimum flows through the shoals during key months for spawning and fish migration.
The agency's suggestion is 4,000 cubic feet per second from February to May, and 2,700 cubic feet per second from June to January.
Optimum flows, Bettross said, are greater than DNR's recommendations, but a compromise was needed to help balance the needs of the shoals with the demands for drinking water taken from the canal.
Currently, he said, flows during dry periods can drop as low as 400 cubic feet per second - a mere trickle.
"The city has been able to operate the dam for almost 150 years, without any regard for the flow in the shoals," Bettross said. "Sometimes the flow is too high, sometimes too low, but both can cause problems."
Access to the river and its shoals is another goal outlined in the relicensing plan.
"It's a prime spot that's not being used heavily," Bettross said. "Part of the problem is access."
Current plans include more recreational use of the canal through the many amenities being added by the Augusta Canal Authority. A courtesy dock on the canal and pedestrian bridge already are planned.
Future additions to the amenities in the area are likely to include a carry-down path from the canal banks to the river, enabling canoeists and anglers to enter the river more easily.
A decision on a new license for the Augusta Diversion Dam and Canal could occur as early as 2004.
ISSUES AT A GLANCE
Reach Robert Pavey at (706) 868-1222, Ext. 119 or firstname.lastname@example.org.