CAP ON WILD WASTE

A CAP ON 80 YEARS OF WILD WASTE By Carrie Bell, Teton County ISWR

Teton County’s Little Horsethief Canyon serves as a reminder that landfilling is an accepted practice but not a permanent solution. Landfilling operations on this site at the southern end of Teton County, Wyoming began in the late 1940s. In those days, no one kept records of what they threw away or gave much thought to what would leak out or how it would impact the ground underneath. The characteristics of the untamed, wild west held true in waste management well into the latter half of the twentieth century. Personal accounts of how trash was handled sounded something like, “you would drive up, find whatever hole was available that day, and throw your trash in.”

Any information about what was underground in these “cowboy” landfills came from limited aerial photographs, GIS mapping, and personal accounts. Garbage from Jackson Hole was deposited at Little Horsethief until 1989, when Teton County began transferring its trash to more modern, lined landfills in neighboring communities and states. In 2009, as part of Wyoming’s landfill remediation program, Teton County began to plan for the official closure and capping of the Little Horsethief Canyon site, as well as the ongoing monitoring and remediation of groundwater contamination from the landfill leachate. Teton County’s Integrated Solid Waste and Recycling department (ISWR) faced the difficult questions of how much waste was in the landfill? How deeply was it buried? And how could the groundwater be protected going forward? ISWR secured local SPET funding and a Wyoming State Loan and Investment Board (SLIB) grant to assist with the costs of the planned remediation.

With initial funding secured, work began to “tame the wild waste!” Early tasks included the excavation of an anticipated 300,000 cubic yards of waste, or enough to fill 40 Goodyear blimps. When it was discovered that removing and hauling this tonnage to the landfill in Bonneville County, Idaho would require a total of 1,043,000 miles, 11 years, and $25,000,000, an alternative plan was hatched.

ISWR partnered with neighboring Forest Service and Bureau of Land Management properties to allow the waste excavated from the County’s property at the west end of the canyon to be relocated further east, upward into the canyon, and eventually capped. Excavation proceeded for two years, into the fall of 2018, and finally totaled 800,000 cubic yards; nearly three times the original estimate and enough to fill 107 Goodyear blimps.

The advantage of such an extensive excavation was that it created additional operating space at the west end of the canyon for the improvement and expansion of waste processing facilities and services. The upgrades included a new scale house, additional space for yard waste composting, and a new food waste composting facility, which served as the interim trash transfer building, while a new 18,000 square foot, multibay trash transfer building was constructed. These facilities, as well as the final landfill cap, are scheduled for completion by winter 2020/2021.

Features of the new Little Horsethief Canyon landfill cap: • Local soil and compost were used as fill material, saving over $200,000. • Once fill material was graded and shaped into the final slopes, a liner and drainage system were installed to allow for the closure slopes to be stable and impermeable. • An added challenge...A Class B fault traverses through the landfill site, so slopes on the landfill cap had to be evaluated to ensure stability and safety in the event of an earthquake. • Once complete, soil will be placed on top of the impermeable layer and seeded for vegetation. • Landfill caps are designed to stop precipitation from entering the buried waste and releasing contaminated leachate.

AUTHOR BIO

Carrie Bell, found her passion for waste diversion and sustainability after going to school for something completely different. She enjoys educating the community and working with community partners on waste reduction.