DEQ Approves Wall

by Susan Watkins

5/30/2013 9:12:59 PM

The Oregon Department of Environmental Quality (DEQ) today gave Waste Management the go-ahead to build a 40-foot high wall on the Highway 18 side of the dump.  The berm, which will be wide enough on top for a road, will allow an additional 1,000,000 tons of garbage to be dumped onto the existing landfill and keep the dump open two more years.

Expansion opponents including the Stop the Dump Coalition argued that neither the proposed berm nor the existing landfill were stable enough to withstand the magnitude 9.0 earthquake experts expect will strike Western Oregon.  DEQ rejected these arguments, relying on EPA rules that DEQ says allow landfills to expand so long as new parts of the landfill meet current seismic standards.

Former Riverbend engineer Leonard Rydell and others with expertise in geology and engineering also pointed out that the assumptions used by Waste Management's engineers in designing the berm are all optimistic; if any one proves inaccurate, the entire analysis fails (see "GeoSyntec's House of Cards" in News below).

DEQ, however, found Waste Management's data persuasive and issued the permit.  The approval gives Riverbend until July 31 to update its operations, site, and environmental monitoring plans to incorporate the berm.

Approximately 9,000 truckloads of dirt and rock must be imported to Riverbend to build the berm.  Waste Management expects to take another 50,000 cubic yards of dirt from the river bank.  The DEQ approval did not address the environmental impacts of berm construction other than to refer to other agencies that issue permits for quarries and for excavation.

GeoSyntec's House of Cards

by Susan Watkins

5/29/2013 3:51:15 PM

GeoSyntec, the firm that engineered the wall Waste Management wants to build on the Highway 18 side of the dump, has assured DEQ (Oregon's Department of Environmental Quality, which decides whether or not the wall gets built) that the wall will be strong enough to withstand a magnitude 8.5 earthquake.

But are GenSyntec's assumptions really sound?  Let's consider:

Under EPA requirements, if the horizontal acceleration generated by an anticipated earthquake is more than 0.1g, the entire landfill must be studied for stability before the wall or any other expansion can be approved.  GeoSyntec found that the horizontal acceleration from the earthquake it studied would be exactly 0.1g.

Geosyntec reached the 0.1g figure by using:

    •    A peak ground acceleration of 0.415g instead of the 0.58g shown on US Geologic Survey (USGS) charts
    •    75km distance from the site of the quake instead of the 50km distance USGS uses
    •    A theoretical return period of 2,357 years instead of the actual historical average of 400 years (five 9.0 magnitude quakes in the past 2000 years)
    •    The upper limit of 12" of bottom interface movement allowed under California Standards instead of the lower limit of 6" (using GeoSyntec numbers, the actual movement would be 10")
    •    A single selected bore hole on the uplands where there is 45 feet of better soil rather than a bore hole in the lowlands with 25 feet or less of good soil
    •    Ignoring failure of the liners at the top of the landfill due to amplification 2.5 times the "g" forces

If any one of these assumptions proves optimistic, the entire analysis fails.  Clearly this is not "conservative" engineering.  Moreover, even with these assumptions, the wall fails to meet the factor of safety for slope stability for earthquakes and will fail at 0.073g when 0.1g is predicted.

The landfill is not safe in even a moderate earthquake let alone the M9.0 Cascadia Subduction Zone earthquake experts predict.  We should close Riverbend now.

FEMA Confirms Landfill Was Built in Floodway

by Susan Watkins

5/9/2013 12:57:39 AM

The Federal Emergency Management Agency (FEMA) has confirmed what the Stop the Dump Coalition has long contended -- that a portion of Riverbend Landfill was unlawfully built in the floodway of the South Yamhill River.

In a letter dated May 2, 2013, FEMA formally notified the Yamhill County Board of Commissioners that the County is "potentially in violation" of federal law due to placement of the landfill in the federally-regulated floodway.

According to the FEMA letter, placing the landfill in the floodway caused a prohibited increase in flood elevations on the river.  Increased flood levels may hasten stream bank erosion and channel change and damage neighboring lands and structures.  Even Waste Management, Riverbend's Texas-based owner, has acknowledged that the river bank is eroding, moving the main channel toward the landfill. 

Opponents of landfill expansion have long contended that landfill owners and managers ignored floodway regulations in the 1980's when Riverbend was originally sited.  In 1992, hazelnut farmer Lee Frease asked the County to determine whether the landfill conformed to County requirements, including floodplain development conditions.  Frease and others pointed to an exchange of letters between the County and the Army Corps of Engineers in 1980-81 to bolster their argument that both the landfill's owners and the County knew the landfill design encroached on the floodway.

Last year neighbors again asked the County to hold a hearing to determine whether the landfill was sited and operating within its land use approvals.  When the County declined, the neighbors sued, losing their appeal a week before FEMA issued its letter of violation.

Although the floodway issue is moot -- FEMA issued new mapping within days after sending its letter -- the County still has a role to play in policing the dump.  To date, however, Commissioners appear to have abdicated their responsibility to oversee the landfill.  Contact your Commissioners to demand they finally take control of this significant cancer on the green bosom of our valley.
Kathy George:  georgek@co.yamhill.or.us
Alan Springer:  springera@co.yamhill.or.us    
Mary Stern:  sternm@co.yamhill.or.us