causing Harshaw Creek outside Patagonia to run. Photo by Marion Vendituoli
The sight of Harshaw Creek filled with water is an unexpected event in winter, and passersby have been surprised to see the creek running since mid-December. The source of the water is not precipitation, but runoff from hydrologic testing at the Hermosa Project by South32.
According to the ADEQ permit application, the pumping would take place for a maximum of fourteen days, between Dec. 15, 2018 and Jan. 18, 2019. The company stated on the application that it would be pumping an average of 2,600,000 gallons of water per day, with an estimated total volume of 37,000,000 gallons of water.
Water is being pumped out of a well that is 1300’ deep, with a pump located at a depth of 1000’. This well is surrounded by a series of monitoring wells. Pumping from a well lowers the nearby water table. This area is known as a cone of depression. Groundwater flows towards the well into the cone of depression, causing the water table of the aquifer to be lowered. The drawdown of water in the shallower monitoring wells will be measured, as will the length of time that it takes the wells to recharge after the pumping is discontinued.
This test is designed to help the company gain a better understanding of the water supply for the mine. “There is no data on the aquifer,” South32 executive Greg Lucero said. “We don’t know how much water we will use. All we are doing now is trying to get a better picture of the aquifer.” The company was not required to get permission from the Forest Service to discharge the water down Harshaw Creek.
According to the watchdog group Patagonia Area Resource Alliance, average daily usage for the town of Patagonia is 66,500 gallons a day, for a total of 931,000 gallons over a 14-day period. Thus, the mine is discharging approximately 40 times more water than the town will use during the same time period.