A few years ago, the slopes of Gold Hill were so pleated with erosion furrows that Mark Walker, who monitors the site for the state Department of Public Health and Environment, compared a drive down State Highway 24 between 21st and 8th Streets to a tour of Bryce Canyon National Park in Utah.

Then the developers of Gold Hill Mesa, not actually a mesa but the tailings pile of one of the country’s richest gold milling plants, graded the slopes and seeded them with grass.

Hay was tacked into the ground as a temporary erosion control measure until the grass could take root.

It was working. This month Gold Hill’s slopes turned green for the first time ever.

Then the rains came. The deluges that washed away the profits of many a Territory Days merchant, and countless Memorial Day barbecues, also etched numerous new erosion channels, called rills, on the sides of Gold Hill Mesa.

“What we had was just kind of an abnormal storm,” said Barry Brinton, development manager for Gold Hill Mesa Partners, which is turning a heap of mine tailings into a housing development. “We were probably a month short from our grass being tall enough to handle the volume of water that came down.”

Gold Hill Mesa is built on the site of the Golden Cyle Mill, which operated from 1905 to 1948. In its heyday, the Golden Cyle processed 1,500 tons of ore a day, mostly mined from Cripple Creek. Nearly 8 million ounces of gold were extracted from that ore. The rest – including the arsenic and lead that occurs naturally in the ore – is what is now Gold Hill.

To keep residents away from the hazardous materials, most of Gold Hill is covered with a gigantic tarp overlaid with topsoil. Any breach of the tarp would be cause for concern.

Water would be one possible cause of a breach. And the site got a lot of water over the Memorial Day weekend.

Tom Magnuson, a meteorologist at the National Weather Service in Pueblo, lives a mile south of Gold Hill and collects weather data at his home. From May 22 to 26, Magnuson recorded 4.98 inches of rain, nearly 30 percent of Colorado Springs’ official annual average.

The worst of the erosion took place on Memorial Day, when 2.28 inches fell according to Magnuson; and the next day, when his rain gauge measured 1.61 inches.

Magnuson said the rainfall was “very unusual” but hardly unprecedented. “The last time I got anywhere near this amount of rain in a three- to four-day time period was back in 1999,” he said.

But Brinton said the erosion rills, while an eyesore, are not an environmental concern. A berm and catch basin system separates Gold Hill Mesa from Fountain Creek, which flows at the foot of the tailings pile.

“We have never had a discharge of sediment or tailings into the stream,” he said. “We never will, because this sediment pond that’s been in place for about three or four years now collects all that sediment.”

Walker agreed. “Sediment is not getting into the creek,” he said. And Tim Vrudny of the CDPHE office in Pueblo, which monitors Fountain Creek, said its water quality had not been affected.

Brinton said he’ll be filling in the rills, doing some earth-moving to redirect water away from areas that have revealed themselves as erosion-prone, and possibly using some “erosion blankets” – a mix of grass seed, starter medium and netting.

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