- Published on Wednesday, 26 March 2014 11:02
- Written by Super User
RALEIGH, N.C. : March 25th – A crack in an earthen dam at the Cape Fear Steam Electric Station in Chatham County has been repaired by Duke Energy crews, the N.C. Department of Environment and Natural Resources reports.
Duke Energy reported to state officials March 20 that a crack had formed in an earthen dam at an ash impoundment at the utility’s Cape Fear plant. No water leaked from the ash impoundment through the crack, and state officials did not think it was in imminent danger of failing.
After DENR staff approved the company’s emergency response plan March 21, Duke Energy started removing water from a horizontal pipe in the ash impoundment and used a plug to stop water from exiting the pond through the pipe. The company then slowly removed portions of the earthen dam where the crack formed to address concerns that the soil in the dam could move and strike the nearby vertical pipe, and lead to a rupture in the dam. That portion of the earthen dam was then flattened and stabilized with a layer of geotextile fabric and riprap. The top portion of the geotextile fabric was anchored to the earthen dam, and the plug in the spillway pipe kept in place.
By excavating the earthen material on the dam and compacting the earth, the crack was repaired. Now, DENR officials will be working with the company on a long-term repair to the dam. DENR is requiring Duke Energy to provide documentation of repairs an engineer made to the dam.
The crack formed in one of two ash impoundments at the facility from which the company had been pumping wastewater over several months. Before state officials were alerted about the appearance of the crack, DENR issued the company a notice of violation for violating the conditions of its wastewater discharge permit by pumping an estimated 61 million gallons of wastewater from both impoundments. Dam safety officials have reported that the accelerated lowering of the ash impoundment could have caused the crack to form in the earthen dam.
Dan River spill update
The latest results of water quality samples taken downstream of the Feb. 2 coal ash spill into the Dan River are similar to previous results in which aluminum and iron, both of which are naturally occurring elements in North Carolina soils, still exceed state surface water quality standards. Results also reveal that arsenic – a key ingredient of coal ash – and other metals continue to fall within surface water quality standards. The latest test results are for water samples collected from the Dan River March 12.
The results are posted to DENR’s “Dan River Spill” page under the lab results heading. You can find the results at http://portal.ncdenr.org/web/guest/lab-results.
The results of DENR’s water quality, fish tissue and sediment sampling from water in the Dan River will help inform the long-term cleanup plan for the river.