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Catawba Riverkeeper Discovers Illegal Seeps from Coal Ash Ponds

Catawba Riverkeeper Discovers Illegal Seeps from Coal Ash Ponds

Catawba Riverkeeper Technical Programs Director Sam Perkins discovered at least three seeps (leaks) into Mtn. Island Lake and one seep into Lake Wylie, which appear to originate from leaking coal ash ponds. These leaks from the ash ponds are unpermitted, unhealthy and illegal. They are of particular concern because the leaks discharge into drinking water reservoirs and because Duke Power does not test the leaking material for hazardous constituents.

Catawba Riverkeeper Discovers Illegal Seeps from Coal Ash Ponds

Riverbend Coal Ash Pond. Photo by Jeff Cravotta. Flight by Southwings.

On November 8, 2012, Catawba Riverkeeper notified DENR and EPA of the existence of at least four apparent leaks of coal ash waste into Mountain Island Lake and Lake Wylie.  These leaks are the result of the storage of coal ash waste in unlined lagoons with earthen dams. 

Lake Wylie (Allen Steam Station)

Lake Wylie is the primary source of drinking water for citizens of Belmont, Ft. Mill, Tega Cay and Rock Hill.  A large seep from the Allen ash ponds was identified below the ash pond dike and sprawls across a section of beach.  At multiple points, free liquid is visibly seeping through exposed sediment on an incised bank and on the Seep from Allen Steam Station Ash Ponds on 20-12-2012ground, and there are a few holes through which water is also flowing.  This exposed sediment on the ground is a dense, bright red clay not visible elsewhere in the area.  Throughout this broad area (~20 ft of beach), there is a visible, trickling flow (notice the channels in the sand and sediment) into the lake.  Catawba Riverkeeper had a composite sample of the leachate analyzed by a certified laboratory and found toxic contaminants commonly associated with coal ash waste including Barium (180 ug/l), Chromium (12 ug/l), Lead (2.3 ug/l) and Selenium (1.8 ug/l).  These concentrations of metals are consistent with levels of known groundwater contamination from the ash ponds that extends under Lake Wylie.  The location of the seep is indicated on the Google Map below (zoom out to see location of leaks on Mountain Island Lake).

View Identified seeps in a larger map

Mountain Island Lake (Riverbend Steam Station)

Mountain Island Lake is the primary source of drinking water for approximately 860,000 people in Charlotte, Gastonia, Huntersville, Pineville, Mint Hill, and Matthews.  On Mountain Island Lake, immediately below the second Riverbend coal ash pond, Sam Perkins identified at least three seeps. 

Seep from ash ponds into Mtn Island Lake on October 26, 2012

  • The first seep runs out of the bank below the ash ponds.  There are multiple places a few centimeters in diameter from which water is bubbling out of the ground. The resulting stream is ~1 m wide and was sampled 6 m above its confluence with the lake.  The sediment where the water flows is brownish-orange.  A sample sent to a certified lab found 22 ug/l of barium.
  • The second seep is near where the ash pond outfall meets the lake.  There are at least a couple of places from which water is bubbling out of the ground, though leaves and other debris help obscure it.  This is a vibrant, orange seep.  A sample sent to a certified lab revealed a definitive coal ash signature of Arsenic (15 ug/l); Barium (110 ug/l); Chromium (9 ug/l); and Lead (2.5 ug/l).  There are other spots on the exposed north bank wall that have bright orange appearance like this seep, but they were smaller or underwater and were not sampled.
  • The third seep recently revealed itself after the water level dropped.  It is to the left of the end of the bridge.  It has not yet been tested. 

Diagram showing compliance boundary and seep locations

The presence of contaminants in seeps around the ash ponds is not particularly surprising because NC DENR has allowed Duke to use the opposite side of the River as the compliance boundary for groundwater contamination.  A group of Riverkeepers, including Catawba Riverkeeper, is currently challenging the compliance boundaries in a case before the North Carolina Environmental Management Commission.  The hearing will be on December 3, 2012.

Duke Energy Response

The seepages don’t come as a surprise to Duke Energy.  Duke spokeswoman Erin Culbert says that seeps are normal and that they’re actually a good sign that the coal ash ponds are working as they should.    

“Seepage, in fact, performs a very important function because it helps ensure that the inside of the dam does not get too moist, too moisture laden, and it also makes sure that there’s not pressure build up inside the dam,” says Culbert.    

Culbert says Duke visually monitors seepages and sends that information to the state, along with water samples taken throughout the two lakes. 

However, the Clean Water Act requires a permit for all approved discharges from the facility.  The NPDES permit for Riverbend, unlike the permits for some other coal-fired powerplants, does not list any seeps from the ash ponds.  If the seeps are normal and expected, they should be listed in the NPDES permit and Duke should be required to regularly monitor and report the level of contaminants in the discharges.

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