Methods of disposing of trash have come a long way since the days when it was common practice to use wetlands as burial sites for garbage. In 1940, a lake located in located on the North Portland Peninsula near the confluence of the Columbia and Willamette rivers was designated as a landfill. It served as the region’s primary garbage disposal site for the next 50 years.
Now the area is being actively restored – providing habitat for coyotes, great blue herons and painted turtles – while Metro continues to manage and monitor the area for future uses.
14 million tons of garbage
The St. Johns Landfill is situated in Metro’s Smith and Bybee Wetlands Natural Area, the largest protected wetland within an American city. By the early 1960s, the former lakebed was filled with garbage to the edge of its surrounding levee. Although the majority of waste in the landfill is domestic solid waste, industrial waste from a pesticide-manufacturing facility was also disposed in the landfill between 1958 and 1962. Metro estimates that up to 14 million tons of waste were disposed in the landfill site during its years of operation.
Covering the waste
In 1980, Metro assumed responsibility for closing the 238-acre St. Johns Landfill in an environmentally sound manner. Metro assumed ownership responsibilities for the landfill from the City of Portland in 1990 and spent the next six years constructing a $36 million landfill cover system to prevent rainwater from leaching contaminants into the surrounding soil and waterways.
The cover’s primary purpose is to keep rainwater from further leaching contaminants from the waste into surrounding groundwater, and to control methane gas generated by decomposing waste. A methane gas collection system draws gas from the waste and pipes a portion of it to a nearby cement company where it is used as fuel.
Today the former landfill site is recognizable only by that methane gas-collection system that crisscrosses its grassy surface.
Since completing the landfill cover in 1996, Metro has spent more than $10 million in ongoing maintenance and monitoring programs, special studies and restoration projects, all funded from garbage disposal fees. In total, Metro has spent about $50 million on landfill closure activities.
In 2003, Metro began to develop a work plan for a remedial investigation of St. Johns Landfill that will identify any remaining risks to health and the environment. Implementation of the work plan began in 2005. Depending on its outcome, feasible measures for controlling risks will then be evaluated. Potential future uses of the landfill will be considered and influenced by the outcome of this study.