VINITA - Grand River Dam Authority reports indicate that dissolved oxygen levels in Grand Lake violated state standards on at least 85 days in a 120-day monitoring period, federal officials confirmed.
Consequently, on Jan. 24, officials at the Federal Energy Regulatory Commission sent a notice to GRDA giving the authority six months to formulate a plan to test minimum flow releases in the summer of 2008 for effectiveness in enhancing dissolved oxygen concentrations and maintaining state standards.
Generation at the Pensacola Dam did not effectively improve dissolved oxygen because, according to the Oklahoma Department of Wildlife Conservation, generation raised dissolved oxygen levels to meet state standards only 25 percent of the time.
GRDA officials dispute the claims of wildlife officials, saying that maintaining the rule curve for Grand Lake is an impediment in terms of having enough water available to maintain dissolved oxygen in the tailwater.
Wildlife officials do not agree. They say that generation releases were not made on 11 percent of the days when violations of state requirements occurred.
“It is clear that, during many periods, as alluded to by the licensee, maintenance of water levels near the rule curve dictated generation,” George H. Taylor, chief of the biological resources branch of the Federal Energy Regulatory Commission, wrote. “Maintenance of lake levels near the rule curve is very important to the heavy recreational use of Grand Lake, and also to the success of required annual fish and wildlife enhancement work such as millet seeding.”
The plan mandated by FERC must also include copies of consultation with state wildlife officials as well as the Oklahoma Water Resources Board and the U.S. Fish and Wildlife Service.
The authority must also afford those three agencies a minimum of 30 days to comment and make recommendations prior to filing the plan with FERC for approval.
GRDA must include descriptions and drawings of the methodology equipment and locations proposed for releasing minimum flows to be tested, detailed information on dissolved oxygen monitoring equipment, methods to be used during the test period, a schedule for the testing and details on when specific flows would be released and under what conditions releases might be curtailed.
The OWRB has designated the river below the Pensacola Dam as a warm water aquatic community, with a minimum dissolved oxygen standard of 6.0 milligrams per liter from April 1 through June 15 and 5.0 milligrams per liter from June 16 through Oct. 16.
A 1.0 dissolved oxygen deficit is allowed for not more than eight hours during any 24-hour period for April 1 through Oct. 15, according to FERC.
Grand Lake has fallen below state standards since 1992 when, according to FERC, GRDA was required to develop and implement a plan to monitor dissolved oxygen in the tailwater and recommend improvement measures.
That portion of the license requires GRDA to continuously monitor dissolved oxygen from June 1 through Sept. 30 each year and to file monitoring results annually by Jan. 31 with FERC.
GRDA filed data for 1996 through 2002 in February 2003, FERC records indicate.
“However, dissolved oxygen concentrations in that data could not be clearly correlated with operation through the period due to limited records and work to upgrade the project's six turbines, which included the installation of air induction equipment on the units,” FERC wrote to GRDA.
Despite enhancements GRDA indicated had been made, in 2005, FERC found that low dissolved oxygen water detrimental to downstream resources was still occurring.