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Oregon Department of Environmental Quality

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Local Projects

Riverbend Landfill

For a summary of this project and current updates, please visit our new overview page.

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.

Following are links to key documents related to Riverbend Landfill.

Environmental Monitoring Plan

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 is found at this link:

DEQ Inspection Reports

July 1, 2014 Report
June 6, 2014 Report
April 30, 2014 Report
April 8, 2014 Report
March 19, 2014 Report
Jan. 28, 2014 Report
Jan. 14, 2014 Report
Dec. 17, 2013 Report
Nov. 12, 2013 Report
Oct. 22, 2013 Report
Sept. 24, 2013 Report
Sept. 10, 2013 Report
Aug. 27, 2013 Report
Aug. 13, 2013 Report
June 25, 2013 Report
Jan 30, 2013 Report
Oct. 24, 2012 Report
Aug. 28, 2012 Report
April 17, 2012 Report
Dec. 22, 2011 Report
Sept. 17, 2011 Report

Leachate Management

Leachate is rainwater that percolates through the waste in a landfill. It is captured by the landfill's leachate collection system and conveyed to a storage pond prior to disposal. In 2011, 21.6 million gallons of leachate were generated at Riverbend Landfill. Approximately 11.9 million gallons were trucked to an offsite treatment facility. The remaining 9.7 million gallons were applied to a 43-acre poplar tree farm on the landfill property through a drip irrigation system. Soil and groundwater are monitored to evaluate environmental conditions at the poplar tree farm. These are documented in an annual report, the most recent of which can be found here:

Recent modifications to the monitoring plan for the poplar tree farm are summarized in the following report:


Floodplain and Flood Way Issues

There was a discrepancy regarding the location of the landfill relative to floodplain and flood way boundary, as shown on flood insurance maps issued by the Federal Emergency Management Agency, or FEMA. On May 31, 2012, Waste Management submitted a request to FEMA for a Letter of May Revision to address this discrepancy. Portions of this submittal are found here:

On December 26, 2012, FEMA issued the requested Letter of Map Revision, which indicates that the landfill is outside the floodplain and flood way boundaries. A copy of the Letter of Map Revision can be found here:

Letter of Map Revision issued by FEMA, December 26, 2012

Mechanically Stabilized Earthen Berm

Waste Management plans to build a mechanically stabilized earth berm along the west side of the landfill. The berm is an earthen wall reinforced with layers of plastic geogrid (Geogrid is a plastic sheet with openings used to reinforce soil structures). This berm would be a maximum of 40 feet high, with a steep outer face (1 horizontal to 3 vertical). It would allow an additional one million cubic yards of disposal capacity. The area of the landfill, currently 84 acres, would increase by 4 acres as a result of the new berm.

More information about the MSE berm is found in a March 2012 report, which is available at the following five links:

Applications for landfill expansions must be accompanied by a Land Use Compatibility Statement issued by the local authority which, in this case, is Yamhill County. A copy of the Land Use Compatibility Statement is here.

Review of geotechnical issues concerning the proposed MSE berm are documented in the following correspondence between the consultant for Waste Management (Geosyntec) and the consultant for DEQ (Hart Crowser). Also provided below are review documents from the consultant for opponents of the landfill (Kleinfelder).

Geosyntec documents

2012 2013
June 22, 2012 Jan. 9, 2013
Sept. 26, 2012 Jan. 16, 2013
Oct. 23, 2012 Feb. 13, 2013
Nov. 7, 2012  
Dec. 7, 2012  
Dec. 26, 2012  

Hart Crowser documents

2012 2013
Aug. 14, 2012 Jan. 2, 2013
Oct. 5 and Nov. 9, 2012 June 26, 2013
Dec. 18, 2012  

Kleinfelder documents

2012 2013
May 11, 2012 Feb. 6, 2013
June 1, 2012  
Oct. 25, 2012  
Dec. 21, 2012  

DEQ has had several discussions with the Oregon Department of Geology and Mineral Industries (DOGAMI) regarding the seismic analysis for this site. Communication between the agencies includes a January 16, 2013 letter, in which DOGAMI recommended that DEQ consider the magnitude 9.0 Cascadia Subduction Zone earthquake in designs for the landfill. Following that letter, DEQ and DOGAMI met twice to discuss the seismic analysis. These discussions are summarized in a Feb. 22, 2013 letter from DEQ to DOGAMI.

A discussion of maintenance and monitoring of the mechanically stabilized earthen berm is also included in the attached document.

Construction drawings and specifications

 

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 never 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 attached report:

Air Quality

Inspections — EPA 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:

Annual Report — The Title V operating permit requires semiannual reports by the facility certifying compliance or noncompliance with the various conditions in the permit. Annual reports containing this semiannual compliance certification as well as other operating data and annual emissions estimates are also required. The 2011 annual report is found in the following link:

Monthly Reports — As a result of citizen input and concerns during the last Title V permit renewal, the most recent Title V permit requires the facility to submit monthly reports concerning operational information, odor complaints, and odor surveys conducted around the landfill. The monthly reports for 2012 to date are shown in the following links:

Monthly reports will be posted to this website as they are received.


Stormwater

Stormwater Pollution Control Plans — As part of the NPDES 1200-Z Stormwater Permit requirements, facilities are required to submit a stormwater pollution control plan. If changes are made onsite to best management practices or other aspects of the stormwater system, updates to the plan are required to be submitted to DEQ.  The following links are the plan, along with any revisions that have been submitted to DEQ:

Discharge Monitoring Reports — Facilities are required to sample stormwater four times per year under the 1200-Z permit.  Riverbend is required to analyze these samples for copper, lead, zinc, pH, total suspended solids and grease, and e.coli. The results from these sampling events are reported on discharge monitoring reports and submitted to DEQ by July 31 of each year. The following links are the reports from Riverbend Landfill:

Action Plans — If any sample results are above benchmarks established in the permit, facilities are required to review their stormwater pollution control plan and submit an action plan to DEQ explaining the benchmark exceedance, as well as corrective actions to meet benchmarks.  Action plans are also submitted when there is a change to the stormwater pollution control plan.  The following links are action plans submitted by Riverbend Landfill:

Future stormwater plans and discharge monitoring reports will be posted as they are received.


Other Issues

Leachate releases — On February 10, 2014, landfill personnel observed leachate escaping from the landfill’s northern boundary. Waste Management reported that this leachate reached a creek approximately 300 feet from the landfill. This leachate was primarily liquid that had collected in the landfill’s gas extraction wells. To keep the extraction wells working properly, this leachate is routinely pumped from the wells to three 22,000-gallon storage tanks near the north side of the landfill. This leachate is kept separate from the majority of the landfill’s leachate, which is pumped to the onsite leachate pond. This reason for this separation is that leachate associated with the gas extraction wells is more concentrated than the rest of the landfill leachate, and is therefore sent to a different offsite facility for treatment and disposal. Tanker trucks that routinely haul this leachate to an offsite treatment plant were unable to get to the site because of heavy snow and icy roads. Flow of leachate from the landfill to the tanks was stopped because the tanks were full. This is believed to be the reason leachate began seeping from the landfill. To prevent this problem in the future, Waste Management has connected these tanks to the pipeline leading to the onsite leachate storage pond.

Impacts to the creek were evaluated in a March 13, 2014 report prepared by Waste Management’s consultant, CH2M HILL. The report concludes that “No mortality of aquatic flora or fauna was observed during either site visit [conducted on February 12 and 21, 2014]. Overall, the impact to aquatic biota was estimated to be minimal on the basis of the high flows of the unnamed creek and the South Yamhill River, and the comparison to aquatic water quality criteria and human health criteria.” A copy of CH2M HILL’s report is found here.

DEQ inspected the site on February 12, 2014. The inspection report, along with photographs, is found here. DEQ concurs with the findings of the consultant's report. However, in light of the release of leachate to the creek, DEQ is pursuing enforcement action against the landfill.

Another consultant for Waste Management, SCS Engineers, sampled soil in the area between the landfill and the creek through which the leachate traveled. Results of the SCS study were provided in a report found here.

A previous seep was found on January 28, 2014, approximately 400 feet west of the February 10 seep. This leachate migrated beyond the perimeter of the landfill, but did not travel far from the landfill perimeter. This release was from an old perimeter French drain that was clogged as the result of recent construction of a stormwater diversion swale. The drain had been installed during construction of the landfill cell to convey leachate to the leachate collection line that runs to the onsite leachate storage pond. To address this problem, the landfill contractor removed all drain rock from the French drain along that portion beneath the stormwater diversion berm. Between January 28 and 29, this rock was removed and the area was backfilled with compacted clay. Four vertical 12-inch sump pipes were installed and backfilled with drain rock. Soil from the impacted area north of the landfill was sampled on January 29. Soil impacted by the leachate release was then excavated, and a vacuum truck was used to remove standing stormwater that may have been contaminated by the release. Soil from this area was resampled on January 31. Results were provided in a technical memorandum dated March 14, 2014, prepared by SCS Engineers. These results indicate that residual contaminant concentrations are below safe levels.

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. These logs are provided at the following three links:

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. During periods of high groundwater, 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.  Descriptions of the liner system used as this landfill are presented in this report, which can be found here:

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. A copy of this report is found here:

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.  The current closure plans are provided in this document:

Financial assurance documents are provide here:


Facility Drawings

Topographic Maps — Landfill contours are documented using aerial photography every year. The most recent topographic map, created in April 2012, is found here:

Expansion of Landfill Gas Management System — The landfill gas management system was expanded in 2012. Construction drawings are found here:

Recent cell construction - The most recent landfill cell was 8D, built in 2009. Construction drawings are found here:

Contact Information

Bob Schwarz: 541-298-7255 ext. 230, toll free at 800-452-4011, or by email
[print version]

 

DEQ Northwest Region
2020 SW Fourth Ave, Suite 400
Portland, OR 97201-4987
Phone: 503-229-5263, FAX: 503-229-6945

Oregon Department of Environmental Quality
Headquarters: 811 SW Sixth Ave., Portland, OR 97204-1390
Phone: 503-229-5696 or toll free in Oregon 1-800-452-4011
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