Sneffels Creek diverted away from Atlas Mill mine tailings
Five organizational partners joined the Uncompahgre Watershed Partnership (UWP) this summer in a project that promises to improve water quality in Sneffels Creek, a tributary to the Uncompahgre River. Sneffels Creek is on the Clean Water Act's 303(d) List of Impaired Waters for cadmium and zinc because its water quality does not support aquatic life. Based on 2012 data collected by the Colorado Water Quality Control Division, the Sneffels Creek site above the Atlas Mill, about seven miles southwest of Ouray, met state water quality standards for cadmium and zinc, while the segment below the mill failed to meet dissolved chronic and acute zinc and chronic cadmium standards at high flows. Besides this indication that tailings might be a source of metals to the creek, erosion of the tailings by the stream's main channel as well as a braid flowing through the tailings was evident.
UWP applied and received a grant from the state Department of Public Health and Environment Nonpoint Source Program, which is funded by the EPA. Our nonprofit also received a cash match for the grant from state’s Division of Reclamation, Mining and Safety, which also provided in-kind services including site assessment and project planning, review of project design and implementation. Additionally, Ouray Silver Mines, the operator of the Revenue Mine below the project, cooperated as the property owner of the area of project implementation, and made an in-kind contribution of stabilization materials. Plus, the U.S. Forest Service collaborated as a neighboring property owner.
UWP hired Bill Coughlin of Western Stream Works to design, permit and implement the Sneffels Creek Bank Stabilization Project. His work consisted of the excavation of a new channel to prevent the creek from flowing through the tailings area, as well as the widening of the channel and floodplain on the east side to alleviate sheer stress on and erosion of the western bank where tailings are deposited. Excavation activities were managed with coffer dams to reduce downstream sediment transport.
The project made successful use of local materials to save time, money and environmental damage by eliminating long distance transportation of heavy and fragile materials. Large boulders and loose stones were excavated from the nearby Potosi slide, transported by front-end loader and utilized in construction of vane arms on the west bank. Established willows were also harvested on-site from areas of the new channel and transplanted to disturbed areas to promote revegetation and bank stabilization. Additional native shrubs, primarily willows, will be hand planted in fall 2016, and herbaceous riparian and upland species will be seeded in 2017.
As the main work on the project draws to a close this fall, water quality monitoring will continue over the next few years to determine the resulting heavy metals levels in the stream. UWP will report on those findings when they become available.
See more photos and a description of the project in the presentation prepared by Bill Coughlin for the 2016 San Juan Mining & Reclamation Conference.