January Leachate Leak??

The following was reported on the Department of Environmental Quality's Riverbend Landfill website (http://www.deq.state.or.us/nwr/RiverbendLandfill.htm) but don't bother looking online for information about the January leachate leak -- that information is no longer there.

Leachate release — 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 21,000-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. 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 the consultant’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.

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 vactor 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. These results indicate that residual contaminant concentrations are below safe levels.