AquaDams Save Rare Algae
The Klamath Basin Bureau of Reclamation oversees Klamath Lake which supplies the irrigation needs of a host of users as part of the Klamath Reclamation Project. A series of drought years that ended in 1993 drew the lake's water to near-record low levels. Because of this historic low, Pete Cartwright, owner of Harriman Springs Resort, near Rocky Point, Oregon, had a problem on his hands.
Harriman Springs has one of Oregon's only three known
concentrations of an algae-like organism called nostoc pruniforme, or Mare's Eggs. The cold water algae produces colonies of round balls whose survival depends on constant water temperatures of 39° to 43° F, and sufficient water depth to provide the thermal layer that protects the eggs from changes in water temperature. As the Bureau continued to send water to its' users, Cartwright watched his Mare's Eggs become exposed. Cartwright realized that there was little time to spare before the eggs would begin to die.
"We were looking to haul logs down there--cut trees and put big logs across the creek to try and raise the water level," says Cartwright. "We were grasping for ideas because we had such a short period of time to react to the situation and get it done."
That's when Cartwright contacted the Bureau of Reclamation and asked for their help. He explained that the eggs had grown from mere specks to the size of baseballs and suggested that it would be a shame for this rare form of algae to die.
According to Cartwright, the Bureau was very responsive. Since they considered this a "natural resource issue," the Bureau sent Mike Green, at that time a field biologist on the lake, to assess the situation.
"The lake was at its lowest levels in recorded history, and thus there was a chance of desiccating these eggs, which are very sensitive to temperature changes," explains Green. Bill Hopkins, an aquatic ecologist with the United States Forest Service, was also consulted. He estimated that it would take 40-50 years for the Mare's Eggs' regrowth, should they die.
The assessment concluded with Green's suggestion that the Bureau install a temporary structure across the outlet of the spring to deepen the pool and provide stable conditions for the eggs. The temporary structure was an AquaDam®.
The project took one day to complete. Two 6 foot high by 100 foot long AquaDams®, inflated with lake water by four 3" discharge pumps, were installed bank-to-bank directly below the site of the Mare's Eggs. The AquaDam® raised the level of the water behind the temporary water-filled dam to approximately 2.5 feet, enough to safely cover the eggs.
"The AquaDam was huge," explains an amazed Cartwright. "I'd never seen anything like it in my life. 'You've got to be kidding,' was all I could say. I was just dumbfounded. But it worked flawlessly."
The AquaDam® remained in place until the Spring when the water level rose to normal levels. According to Cartwright, the Mare's Eggs survived and are now thriving.