Explaining proposed Lake Keowee water levels

By Steven Jester
Duke Energy
Guest Editorial

Lake Keowee has been a central force in the Upstate since Duke Power constructed it in the late 1960s. Its turquoise waters support regional economic development, electricity production, municipal water supplies and downstream water needs, and provide a beautiful place to live, work and play.

Those who have lived in the Upstate for some time might recall that Lake Keowee used to fluctuate much more than it does today. Through the 1970s and 1980s, it fluctuated by as much as 16 feet, and the current federal hydro operating license allows Duke Energy to operate the lake as much as 25 feet below full pond.

Much has changed at Lake Keowee since the original license was issued in 1966. One of these key changes has been Nuclear Regulatory Commission requirements for Oconee Nuclear Station. Though the station was originally designed and constructed to operate with Lake Keowee at a 25-foot drawdown, requirements have evolved since the 1990s so that’s no longer the case. Duke Energy currently operates the lake within a narrower range of 5.4 feet below full pond or higher except during planned maintenance periods.

This means that, under the current license, an extreme drought could render Oconee Nuclear Station inoperable, with the possibility for Lake Keowee to go 25 feet below full pond. This is not desirable for public water suppliers, businesses, lake users, residents or the community at large. And it’s certainly not ideal for Duke Energy.

The Keowee lake levels Duke Energy proposes for the future will improve conditions for lake users and help prepare the community to withstand droughts.
The current federal license controlling Lake Keowee’s operation will expire in 2016. Enter the relicensing process. A broad group of community members and local, state and federal governmental representatives is working to prepare a new license agreement to present to the Federal Energy Regulatory Commission outlining how the region believes Jocassee and Keowee hydroelectric stations should be operated for the next 30 to 50 years.

To get the stakeholder agreement negotiation kicked off in earnest, Duke Energy recently developed a draft proposal for a number of things, including future lake level management. Some lake residents have expressed concern about Duke Energy’s proposed levels for Lake Keowee, and a wide variety of interpretations of our current license and draft future recommendations has created some confusion.

Under times of normal water availability, Duke Energy proposes to operate Lake Keowee much as it does today — no lower than 5 feet below full pond. If we experience similar weather conditions in the future as we have in the last 70 years, computer modeling suggests Lake Keowee would be at this level or higher 96 percent of the time.

To manage through dry periods in the coming years, Duke Energy’s proposal includes a plan for coordinating drought response. This proposed “Low Inflow Protocol” (LIP) includes five stages and outlines how Duke Energy would step down reservoir levels and decrease water releases downstream to conserve water as droughts intensify. Duke Energy also plans to modify Oconee Nuclear Station to allow it to operate through a greater range of lake levels — down to a maximum of 10 feet below full pond.

Drought management strategies in the proposal would provide a more gradual pace for water releases downstream, preserving higher levels in Lake Keowee about 25 percent of time than if we continued to operate the way we have been for the past several years.

The LIP stages graduate based on drought severity and use objective data to determine each stage. Lake Keowee would reach its lowest point only during extended drought and very infrequently. Modeling suggests with historically similar weather conditions the lake would be between 7 and 10 feet below full pond less than 1 percent of the time.

It’s important to recognize that water demand will increase with economic development activity. A water supply study conducted as part of this relicensing process thoroughly evaluated long-term water needs in the Savannah River Basin. Water consumption is expected to more than double in the next half-century. If Duke Energy makes no modifications to Oconee Nuclear Station and the expected growth in water withdrawals occurs, Keowee’s lake level will still fall below today’s minimum of 5.4 feet below full pond during severe droughts and could fall to levels requiring our nuclear station to cease operations. Duke Energy wants to see the region continue to grow, but it’s not going to be possible to continue the growth and maintain the status quo with regard to Lake Keowee’s elevation during droughts.

Through the ongoing negotiations with the relicensing stakeholder team, the region has a unique opportunity today to prepare for future water needs. As the stakeholder team continues its negotiations, the draft agreement will change, and there are certainly no done deals at this point for any issue, including lake level management. Duke Energy simply asks that we provide the stakeholder team members room to do their job.

Steve Jester is the vice president of Water Strategy, Hydro Licensing and Lake Services at Duke Energy.