Riverbend Landfill is approximately three miles southwest of McMinnville in Yamhill County. The 87-acre landfill began accepting waste in 1982 and has expanded since that time. The landfill owner, Waste Management, has pursued an expansion involving a 29-acre group of disposal cells to be located west of the existing landfill. Their expansion application included a Land Use Compatibility Statement dated March 9, 2016. On Aug. 20, 2020, the Yamhill County Board of Commissioners adopted Board Order 20-287 to deny applications for Site Design Review and a Floodplain Development Permit for the Riverbend Landfill. Based on this decision by the county, DEQ concluded that the 2016 LUCS is not valid. On Sept. 16, 2020, DEQ therefore denied the April 23, 2015 expansion application.
Status of landfill operations
Operational changes beginning July 1, 2021
Riverbend Landfill notified DEQ that, beginning July 1, 2021, their public disposal and recycling area will be closed for acceptance of waste and recyclables. The landfill will continue to accept petroleum contaminated soil and select loads of solid waste to fill in areas to aid in achieving proper slopes and grades in preparation for final cover or capping. The landfill has curtailed the type and amount of waste accepted but it has not closed.
This change is reflected in the latest version of the facility's Operations Plan.
The Operations Plan refers to the facility's Special Waste Management Plan.
Landfill capping
During a landfill's life, the landfill operator installs a watertight cover over portions of the landfill that have reached capacity. Approximately 28 acres of the 87 acres at Riverbend Landfill have already been capped.
Closure and post-closure plan
The closure and post-closure plan for Riverbend Landfill was last updated in November 2017.
DEQ has not issued a closure permit for this site because the closure date for the landfill has not been determined. However, DEQ reviewed the closure and post-closure plan and deemed it acceptable.
Closure and post-closure financing
Landfills are required to set aside funds sufficient for proper closure of the landfill and 30 years of post-closure maintenance and monitoring. Estimates of the necessary funding must be revised every year.
Solid waste permit modification would require a new Land Use Compatibility Statement
DEQ denied Waste Management's permit modification application in September 2020 because the company did not have an approved Land Use Compatibility Statement, or LUCS, from Yamhill County. The company, which had applied in 2015, may reapply for a permit modification related to expansion plans.
Air, land and water permits
DEQ is responsible for managing three permits for the facility:
These permits contain the limits, standards, monitoring, testing, recordkeeping, and reporting requirements based upon Oregon statutes, DEQ rules, or federal rules.
DEQ regulation of Riverbend Landfill leads to inspections, reports and other documents. Agency records relating to Riverbend are public records and many are found on this webpage. Additional records are available at public request through DEQ's Public Records Request Center.
The Title V operating permit requires annual reports by the facility certifying compliance or noncompliance with the various conditions in the permit. Annual reports containing this compliance certification as well as other operating data and annual emissions estimates.
Proposed Landfill Expansion
Waste Management has submitted an application for a 29-acre expansion of the landfill. DEQ is reviewing the application documents, which include:
Waste Management has permit coverage under the 1200-Z National Pollutant Discharge Elimination System general permit with DEQ for industrial stormwater discharges at Riverbend Landfill. This general permit authorizes the facility to discharge industrial stormwater to surface waters of the state. This general permit may be reviewed on DEQ's Industrial Stormwater Permits website, along with a variety of technical assistance documents.
The general permit requires the facility to create and maintain an accurate Stormwater Pollution Control Plan and site maps that describe how the facility manages industrial stormwater, what specific controls are in place to achieve the goals of the permit, where stormwater monitoring occurs, and where stormwater discharges from the facility, among many other details as outlined in Schedule A of the 1200-Z permit.
The general permit requires the facility to collect samples of industrial stormwater, analyze the stormwater samples for specific pollutants, and summarize the monitoring results on Discharge Monitoring Reports four times per year. Refer to Schedule B of the 1200-Z permit for the monitoring requirements and reporting frequency.
Other reports may be submitted throughout the year, such as corrective action reports and revisions to the Stormwater Pollution Control Plan. A summary of reporting requirements can be reviewed on page 31 of the current 1200-Z NPDES permit or on page 37 of the 1200-Z permit that will become effective July 1, 2021.
Copies of the most recent Stormwater Pollution Control Plan, Discharge Monitoring Reports, or any other available documents associated with this facility may be requested from DEQ through the Public Record Request Center.
Boring Logs
Numerous studies of hydrogeologic conditions have been conducted by Waste Management's consultants. These are based on boring logs that are recorded each time a well or piezometer is drilled. Monitoring wells are used to draw water samples for lab analysis, and to measure the elevation of the groundwater surface.
Elevations of groundwater relative to bottom of waste
Waste Management's consultant prepared a report in November 2012 that assesses groundwater elevations relative to the elevation of the bottom of waste at the landfill. As shown in this report, the elevation of groundwater is higher than the bottom of waste in portions of the landfill. It is important to note that the waste lies above a liner that prevents the escape of contaminants. The liner system has become increasingly substantial as new sections of the landfill have been built, to provide a more effective barrier between waste and groundwater.
The report does not evaluate the three oldest cells (Modules 1 through 3), whose liner systems consist of low-permeable soil but do not include plastic geomembranes. This is because the consultant was unable to find base grade information for these older landfill cells.
Environmental monitoring reports
The facility's permits require the company to monitor environmental conditions at the site in accordance with the facility's Environmental Monitoring Plan.
The facility records the results of this monitoring in an annual environmental monitoring report. The most recent of these reports are:
Water quality 1200-Z permit
Documents related to the 1200-Z permit for Riverbend Landfill include:
Groundwater Quality
There is localized groundwater contamination, as indicated by the presence of volatile organic compounds in one groundwater monitoring well. Volatile organic compounds are of particular importance in evaluating a landfill's effects on groundwater for a couple of reasons. They move fairly quickly through groundwater and therefore provide an early indication of a problem. Unlike other contaminants, such as metals, most volatile organic compounds do not occur in nature, so if they are detected, they are likely from the landfill. We suspect the contaminants found in this well may have been carried by landfill gas moving under the ground. Concentrations have dropped over the years, primarily because the owner has installed an extensive landfill gas removal system.
Low concentrations of volatile organic compounds have also been detected in other wells but subsequent sampling has not found the compounds in these wells. The permit requires that if a volatile organic compound is detected and is not due to sample handling or lab contamination, the well must be resampled to confirm the presence of that contaminant. Confirmation sampling has not shown the presence of volatile organic compounds in any of the wells, other than the one mentioned above.
More information regarding this is found in the report, Evaluation of VOC Detections
Inspections
DEQ officials inspect Riverbend Landfill in accordance with the facility's air, land and water quality permits.
Air quality inspection reports
The U.S. Environmental Protection Agency and the Title V operating permit program require that inspections of the facility occur at least every other year. Prior inspections of the facility have shown it to be in compliance with the Title V permit conditions. The inspection reports for 2010 and 2012 are found below:
Solid Waste inspection reportsWater quality inspection reports
The NPDES 1200-Z General Stormwater Permit compliance can also be evaluated through an on site compliance inspection.
Nuisance odor investigation
After receiving a sufficient number of complaints, DEQ has started a nuisance odor investigation at Riverbend Landfill. The investigation is a step in DEQ's Nuisance Odor Strategy. As part of the investigation, DEQ will be conducting odor surveys periodically throughout the year.
Potential for migration of the South Yamhill River
Residents have expressed concern about the potential for the South Yamhill River to migrate over time, because it could therefore move closer to the landfill. This issue was evaluated in a September 2012 report by Waterways Consulting, Inc. The report concludes that the river has not migrated in this direction substantially in the past. Among the factors considered, the report points to the presence of 3,000-year-old Native American artifacts found in the land between the river and the landfill.
Topographic Maps
Landfill contours are documented using aerial photography every year.
Contact
Dylan Darling, DEQ Communications, 541-600-6119