Why You Should Worry About the Big One

By Leonard Rydell

Riverbend Landfill is out of control, and the Oregon Department of Environmental Quality (DEQ) is determined to ensure that, at any cost, the dump continues to grow.  This is not right.  Let me explain.

I am a consulting Civil Engineer, Professional Land Surveyor, and Water Rights Examiner licensed in the State of Oregon, and this year am celebrating my 40th year of professional practice.  I have been following Riverbend Landfill since 1982 when I laid out the original survey coordinate system for Riverbend, revised the original construction plans, and -- for a brief while -- was the Engineer of Record until my concerns over Riverbend Landfill's failure to meet the landfill's design and specifications led me to resign.

It was obvious to me even then that Riverbend Landfill was going to become a major environmental hazard and that the DEQ would be no help.  I laid out Cells 1, 2 and 3.  When I measured ground water levels, I learned that ground water would move in and out of  garbage placed in those cells.  Despite rules that required 95% compaction, DEQ allowed garbage to be placed below ground water levels in those cells when DEQ's own tests showed compaction of cell bottoms to be no more than 60% during the first four years.  

The original design was for the landfill to rise to a height of 157 feet above sea level, ie, 7 feet above the surrounding farm fields and Highway 18.  After the original Yamhill County and DEQ approvals, I was asked to revise the plans to steepen the slopes so that the dump could rise 28 feet above the top of the farm fields on the uplands.

In the 1980's, earthquakes were not even discussed as part of an engineering design.  None of the original 8 cells of Riverbend Landfill have ever been studied to determine whether they will withstand a major earthquake (7.5 or larger), yet the DEQ continues to allow garbage to be added to the landfill, now piled up to 135 feet above surrounding farm fields (yes, that is a 108 foot increase from 1982).

Cells 4 and 5 have been studied to a 7.25 magnitude earthquake.  A 9.0 magnitude earthquake like the Big One we are expecting is 56.234 times stronger than a 7.25 earthquake but releases 421.696 times the energy.  It is not the same as paying $9.00 for lunch instead of $7.25.

But wait, there is more!  The July 1993 study for Cells 4 and 5 for a 7.25 earthquake was based on landfill slopes of 4 feet horizontal to one foot vertical, yet the DEQ is allowing a steeper 3.5 feet horizontal to one foot vertical slope and a maximum height 46 feet higher than that approved by the 1993 study.  Recently I asked the DEQ permit engineer when the increase in height was approved and what the design calculations were.  His reply was that a 3.5 foot horizontal to one foot vertical slope is "allowed by administrative rule."   To me, that is like adding four floors to a skyscraper without requiring engineering calculations because the additional height is allowed under the zoning code.

My concern about the earthquake stability of the landfill should also be your concern.  The 20 July 2015 New Yorker Magazine contains an excellent article about the Cascadia Subduction Zone Earthquake, the Northwest's "Big One."  See http://www.newyorker.com/magazine/2015/07/20/the-really-big-one.  As Kenneth Murphy, FEMA’s Region X (Oregon, Washington, Idaho, and Alaska) Director says, "Our operating assumption is that everything west of Interstate 5 will be toast."

DOGAMI's Yumi Wang points out that we must also worry about soil liquefaction.  In her Hospital Report for Yamhill and Lincoln Counties, she says, "In addition to damage to bridges from earthquake shaking, damage would occur from tsunami flooding to road segments in low lying portions of Highway 101 especially near the Siletz River, from landslides especially toward the western portion of Highway 18 (ODOT mileposts 13 to 18); and from liquefaction especially between Sheridan and McMinnville."  In case you don't know, Riverbend Landfill is located on the river side of Highway 18 between Sheridan and McMinnville.

Look for my next article on water and the dump.