Study shows 15 years of healthy fish and clean water downstream from SURF

The latest report in 15 years of annual studies on the health of the aquatic ecosystem and water quality in the creeks downstream from the water discharge at the Sanford Underground Research Facility (SURF) shows excellent results.

“We do annual biomonitoring that includes tests on the health of the fish population and the plants and animals in the aquatic ecosystems downstream from our water treatment plant at SURF and for 15 years we have no measurable negative impact on the creeks in this area,” says Bonita Goode, environmental manager at SURF. “Fish tissue analyses also indicated that selenium concentrations were well below the chronic selenium threshold. No evidence of negative impacts from our discharged water were observed in fish, invertebrate, or periphyton populations in 2023 or in any of the previous 14 years of biomonitoring.”

Goode adds that SURF’s water discharge supports aquatic life in Gold Run Creek that is not present upstream of SURF discharge. “We actually help that downstream ecosystem thrive with our discharge,” Goode said. Since water treatment at SURF started, the facility has discharged about 15 billion gallons of treated water into the aquatic ecosystems of Gold Run and Whitewood Creeks.

SURF occupies what was once the deepest gold mine in North America. The 370 miles of drifts and shafts that spread out below the town of Lead follow the gold bearing ore body into the earth to a depth of more than 8000 feet.

The vast network of tunnels below this part of the Black Hills is continually filling with water that percolates in from the surface. SURF does not do any mining on the site but maintains a laboratory space 4850 feet below the surface that is host to a range of world-class experiments. To keep the lab space dry, SURF continually pumps water from the underground. This water contains concentrations of iron and other naturally occurring contaminants that must be removed before it is released into Gold Run Creek.

SURF operates an onsite wastewater treatment plant to clean the water that comes up from the underground. SURF also treats water from the Grizzly Gulch tailings impoundment, which was operated by the former mining company. SURF treats between 500-1500 gallons of water per minute that includes a mix of the underground and tailings impoundment water.

Doug Coolley is one of the water treatment plant operators at SURF who are on hand 365 days a year to complete daily water testing for contaminants like ammonia and total suspended solids. “Every day we do at least two samples,” says Coolley. “We do a composite sample, a grab sample, and a test of the total suspended solids, to make sure the system is working to reduce and remove those contaminants before the water is discharged.”

“Just knowing the water we discharge improves our local environment is a good thing, the bugs thrive downstream and this means the fish thrive as well,” said David Johnson, the Wastewater Treatment Plant superintendent at SURF who has spent much of his career working to protect water quality in the Black Hills.

Water treatment and testing will be needed at SURF for as long as the facility is operational and dewatering the underground laboratory space. One of SURF’s core values is protection of the environment, and the facility is committed to preserving water quality in the Black Hills in the decades to come.

Those interested can read the entire report, published in January of 2024, here.