Ash basin closure protects lake

August 19, 2013 

The Catawba Riverkeeper has expressed concerns about Mountain Island Lake’s water quality. We share that focus and dedicate significant resources daily to monitoring water quality across all the regions we serve.

Duke Energy began monitoring the lake in 1953, long before the Clean Water Act, and more than four decades before the Catawba Riverkeeper Foundation was formed.

Test results have always proven and continue to demonstrate the region’s drinking water supplies are safe. Monitoring near Charlotte’s drinking water intake downstream from Riverbend Steam Station consistently finds arsenic levels at less than 1 part per billion. That’s 10 times below the state surface water standard. It’s also less than the lowest amount laboratory instruments can accurately measure.

The same is true for other trace metals, such as cadmium, chromium, lead, nickel and selenium. Coal ash is less than 1 percent trace metals, but we are required to test for them routinely.

Water quality and drinking water supplies in Lake Norman and Lake Wylie are similarly well protected. We’ve invested millions to upgrade to even cleaner ash storage methods at larger stations as technology has evolved.

We continually work to balance the needs of customers, delivering reliable, affordable electricity and investing prudently to meet and exceed all regulatory requirements.

Riverbend has been portrayed in recent years as a looming menace. Nothing could be further from the truth. The employees who operated the station for more than eight decades did so with dedication to safety, environmental stewardship and operational excellence.

Riverbend served this community well, but its lack of advanced air emission controls required that it be retired; that occurred two years early in April. By the end of this year, Duke Energy will have retired seven of its 14 coal plants in the state as part of our investments to meet customers’ needs in cleaner ways.

Retiring Riverbend hasn’t eliminated the riverkeeper’s rhetoric about its ash basins, now pointing to wet spots and small amounts of seepage that contain very low levels of these ash constituents as reasons for grave concern. Since Riverbend’s retirement, barely a trickle of water returns to Mountain Island Lake from the plant’s ash basins.

Are some of those unpermitted discharges? That’s a technical legal question.

Are they impacting the water quality in Mountain Island Lake? Absolutely not.

With Riverbend’s retirement comes the decommissioning and demolition of the plant and the closing of its ash basins. As milestones develop, we’ll keep the community informed.

We appreciate the riverkeeper’s interest in closing the ash basins properly. We couldn’t agree more. To that end, Duke Energy is hiring additional technical experts to perform scientific and engineering studies to recommend the most appropriate closure method.

Because each plant site is different, the engineering solution needs to be customized. Once we have the data to support the right decision, we’ll submit the Riverbend ash basin closure plan to the state as required by the station’s permit. The plan will be technically sound. It will comply with federal and state regulations to protect air and water. And it will be the best fit for Mountain Island Lake to continue effectively protecting its water quality for generations to come.

Jason Allen is senior vice president of environmental, health and safety for Duke Energy.

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