Santee Cooper working to mitigate flooding risks at Grainger ash ponds
MONCKS CORNER, S.C. – Anticipating near-record flooding on the Waccamaw River projected by the National Oceanic Atmospheric Administration (NOAA) over the next several days, Santee Cooper has been working to mitigate potential impacts to its ash ponds under excavation adjacent to the river in Conway, S.C.
NOAA is projecting the Waccamaw will reach a height of 17.1 feet by Wednesday, Sept. 19. That is near the record 17.9 feet reached after Hurricane Matthew in 2016 and would be 1-3 feet from the top of the pond dikes. NOAA’s projection is early and subject to change over the next few days.
Santee Cooper has been excavating the ash from its two ponds at the former Grainger Generating Station since 2014, transporting most of that ash to cement and concrete suppliers who are recycling it as a raw material in their products. Approximately 1.4 million tons have been excavated, and an estimated 200,000 tons remain on site, mostly in Ash Pond 2. Most of the ash has been removed from Ash Pond 1, and approximately 30 acres (three-fourths of the pond) has been tested clean and approved by S.C. Department of Health and Environmental Control.
Some 30 employees have been preparing the Grainger site this week for significant rainfall expected from Hurricane Florence. Workers have built a temporary dike to protect the cleaned section of Ash Pond 1, and they are pumping water from the Waccamaw into the ash ponds to help balance the pressures on the earthen dikes as the river rises. There are 15 portable pumps, numerous pieces of heavy equipment, rock and other materials in place for use as needed. There are also several hundred tons of rock already bagged in 1.5-ton sacks, which can be lifted into place by helicopter if needed to address any potential breaches in the dike. The helicopter is under contract and will be on standby at the Myrtle Beach International Airport.
This strategy is similar to the successful efforts that protected the integrity of the ash pond dikes in 2016. Santee Cooper will continue to monitor the situation and respond proactively.