To deal with ongoing drought conditions, GRDA seeks rule curve variance from FERC

Vinita – In response to the ongoing drought that continues across much of Oklahoma, and to better manage Grand Lake due to low inflows from the watershed, the Grand River Dam Authority is again asking the Federal Energy Regulatory Commission (FERC) to consider a variance to the lake’s mandated elevations.

FERC issues GRDA its license to operate the Pensacola Project (Pensacola Dam and Grand Lake) and that license contains a seasonal rule curve that mandates GRDA hold the elevation of Grand Lake at certain levels at different times of the year.  Those elevations range from 742 feet in the spring to 744 feet during the busiest portion of the summer boating season and a 741 elevation during the annual mandated drawdown in the early fall.

The drought conditions that have now lingered for more than a year prompted GRDA to ask for, and receive, a rule curve variance in August 2012. Due to that variance, GRDA did not proceed with the annual drawdown of Grand Lake to the 741 foot elevation. That preserved enough water in Grand to provide the necessary releases into the downstream reservoir, Lake Hudson, to conduct mandated dissolved oxygen testing through last October.

“Last year, the FERC variance allowed us to respond to the drought in a way that balanced all the interests that depend on both our Grand and Hudson lakes,” said GRDA Chief Executive Officer/Director of Investments Dan Sullivan. “We were able to complete our dissolved oxygen testing, continue reliable operations of our Salina Pumped Storage Project (located on the Saline Creek arm of Hudson) and maintain sufficient water levels for the many water districts that depend on Grand and Hudson for their supplies.”

Unfortunately the continuing drought means GRDA is facing similar issues already in 2013. In a letter sent to FERC earlier this week, Sullivan asked FERC to consider the variance which would allow GRDA to “adaptively manage the Pensacola reservoir based upon current weather conditions and outlooks.”

Sullivan informed FERC that, based upon regional drought conditions throughout most of the central plains and the Seasonal Drought Outlook released by the National Drought Mitigation Center, the drought is expected to persist and intensify in the coming months. In its recent communications with the United States Army Corps of Engineers (USACE) GRDA has learned that the Corps’ John Redmond reservoir (located upstream in Kansas) is nearly 4 feet below normal. As a result, the Corps opted to store additional water in Redmond, meaning that water will not flow into the watershed, and eventually into Grand Lake.

“This is a good reminder that the drought’s effects are widespread and not just on GRDA lakes,” said Sullivan. “That is why it’s so important to make this request of FERC now, so that we can all continue to work together across this region to balance all interests.”

GRDA’s new request to FERC is really twofold. First, it is asking for a variance that would allow it to go below the current Grand Lake rule curve during the drought period. Until there is sufficient inflow into the Grand River watershed, GRDA needs the ability to lower Grand so that it can address the continuing dissolved oxygen issues downstream on Hudson and also meet contractual obligations with the city of Tulsa. Lake Hudson is secondary source of drinking water for Tulsa.

In the other part of its request, GRDA is asking for a variance to go above the 742 foot elevation from now until May 31, 2013, in the event that some rainfall is received during the normal rainy season in the spring. That extra inflow could then be stored and would help GRDA to raise the lake to the normal 744 foot mark in the summer, if the drought persists. GRDA has also requested to forego the annual drawdown to the 741 foot mark in August, to also combat the continuing drought.

“This is an adaptive management approach that will allow us to address many issues we may face during the summer months,” said Sullivan. “The same reasons we asked for the variance last year are still in place and we need to be proactive in managing our reservoirs for the good of all interests.”
GRDA submitted its request to FERC on March 4. A final decision is pending.


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