6 3 4 5 2 1 Arapahoe Basin Ski Resort Keystone Snake River Chihuahua Gulch 3 Keystone Snake River Keystone Ski Resort Peru Creek Pennsylvania Mine 4 5 Cinnamon Gulch 2 ACID MINE DRAINAGE Montezuma CURRENT STATE OF THE WATERSHED SLIDE Dissolved concentrations of many metals of biological concern is pH dependent Thus, pH of the stream is the dominant controlling factor of the distribution of metals in the dissolved or colloidal phase In this figure, pH is plotted in 3 discrete intervals Notice the 3 apparent main sources of pH related stress in the system, the Pennsylvania Mine, Cinnamon Gulch, and the Upper Snake River Upper Snake River, iron oxide precipitation, natural sources, has it’s own flora and fauna that exist under these extreme conditons The Pennsylvania Mine, large producer of Summit County silver into the mid-1940’s, continues to produce, now believed to be one of largest sources of aqueous metals and acidity in the watershed AMD discharge into Peru Creek from the Pennsylvania Mine, not end of the pipe, oozes out of the bank over a stretch of river Visible delineation between low pH / iron oxides, pristine Chihuahua Gulch, and higher pH, aluminum oxides Nice riffle pool meandering stream. Might expect to see trout in here… Town of Keystone, traditional environmental indicators of acid-rock drainage (i.e. bright-orange / white coated substrates, low pH) are muted, pH recovers to circum-neutral and stream substrates are less visibly coated with metal-oxides Sts. John Creek Sts. John Key: Instream pH <4.3 4.4-5.7 >6 1 NATURAL IRON BOG Deer Creek Upper Snake River From: Fey, D. L., S. E. Church, et al. (2001)