Geog 322: Geomorphology, Winter 2001, University of Oregon

Debris Flows -- Exercise 7

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They are called debris flows by geomorphologists, landslides or mudslides by journalists, and "rapidly moving landslides" in Oregon laws, but they are all basically the same thing.  The political controversy about debris flow hazards in Oregon was started by the Hubbard Creek debris flow in November 1996 that killed four people.  The controversy continued through 1997 to 1999, when our current laws and policy on debris flow hazards were passed.  The controversy continues today, as the final rules and procedures related to debris flow hazards are still being developed.  The links below will lead you to articles and web pages that describe the current laws and policies, the Hubbard Creek event, the political reaction to it, and how the current laws evolved in 1997 and 1999.  

For exercise 7, you will conduct a debate (really more of  a public hearing) in lab meetings during week 8 (Feb. 27 and 28).  Click here to go to the assignment.  

There is a lot of interesting material on this topic.  Articles marked with a symbol are the most important articles under each topic.  If you don't have time to read everything, start with these.  

As you read these articles, be aware of the source and the viewpoint of that source.  Newspaper stories (mainly from The Oregonian) are supposed to tell what happened, factually.  Editorials are opinions written by the newspaper staff.  Op-ed pieces are editorials, written by individuals or groups, that are considered worthy of publication in the newspaper.  Letters to the editor are short statements of opinion written by individuals or individuals representing an organization.  State agencies are expected to represent laws, rules, policies and positions voted and passed by the Oregon Legislature (elected so expected to be representative of the citizens), developed by the Governor (elected), or voted into law by the citizens in the initiative or referendum process.  

U.S.G.S. web page on debris flow hazards in the U.S.  

   Law and policy related to residential, urban, and commercial development:  

Land use planning and approval of new residential, commercial or industrial developments is regulated through local governments and the Oregon Department of Land Conservation and Development (ODLCD).  Oregon law requires local governments (counties or cities) to develop comprehensive plans that meet certain state-wide land use planning goals.  The state-wide goals address social, economic and environmental concerns.  Debris flow hazards were included in this planning process by the law (SB 12) passed by the Oregon legislature in 1999.  As in the forest practices rules (below), the intent was to protect public safety  (to reduce the risk of serious injury or death from debris flows) rather than protect the environment.  SB 12 required mapping of areas with high debris flow hazards (called “further review areas”).  The Oregon Department of Geology and Mineral Industries (DOGAMI) is preparing these maps and they are expected to be issued in 2002.  If a proposed building site falls within a “further review area”, the developer may be required to conduct a detailed engineering study of the site, to take extra mitigation measures, and to meet higher development standards. 

For more information, see Planning for Natural Hazards:  Oregon Technical Resource Guide on the ODLCD web page. This on-line publication explains planning for natural hazards for local planning agencies.    Go to Section 3, p. 17-20, for a good explanation of Oregon laws and programs related to landslide hazards. 

For more information on Oregon land use planning in general, go to the ODLCD web page.  

   Law and policy related to forestry:  

In Oregon, timber harvest and related activities on private lands are regulated under the Oregon Forest Practices Act.  Forest practices are regulated to ensure reforestation, to protect streams and aquatic resources, to protect water quality, and to protect public safety.  The Oregon Department of Forestry (ODF) administers the forest practices laws.   Anyone wishing to conduct a timber harvest or build a road for timber harvest is required to notify the ODF and to conduct the operation following best management practices as defined in the Oregon forest practices rules.  ODF inspects timber harvest operations to ensure that the rules are followed.  If the operation might affect water quality or other environmental resources, ODF requires a written plan to be submitted before the operation, and ODF must review and approve the plan before operation can proceed.  

In 1999, the Oregon forest practices laws were modified, by Senate Bill 12, to reduce debris flow hazards.  The motive stated in SB 12 is to protect public safety (not for environmental protection). (SB 12 directed the ODF to develop official rules (Oregon Administrative Rules), but these rules are not expected to be formally adopted until late in 2001.  Meanwhile ODF is operating under interim procedures authorized under SB 12.)  

Under the current policy, ODF prohibits timber harvest or road-building on “high risk sites” if a rapidly moving landslide initiated on that slope is expected to reach an occupied dwelling or a high traffic volume road.  High risk sites are located in western Oregon (eastern Oregon is thought to have less debris flow hazards).  High risk sites are defined as: any slope steeper than 80% or any headwall (concave slope at the head of a small valley or draw) steeper than 70%, except in the Tyee sandstone (common in the Coast Range from the latitude of Eugene south to around Coos Bay) where slopes steeper than 75% and headwalls steeper than 65% are considered high risk.  The rapidly moving landslide is expected to reach or endanger a building or road if 1) the valley leading from the initiation site to the building or road is steeper than 6% and narrower than 200’, or there is evidence that previous debris flows have traveled as far as the building or road (fans of old debris flow deposits), and 2) the building or road is within 200’ of the valley that meets the criteria above.    The ODF debris flow hazard maps are used for initial screening, but actual on the ground measurements are used to evaluate the criteria stated above, to determine whether the proposed timber harvest will be prohibited or allowed. 

For more information, see Forest Practices Technical Note Number 2, “High risk sites and rapidly moving landslides: Identification of locations where there is significant risk to public safety”. 

New development:  New rules limiting logging on landslide-prone slopes are currently (spring 2002) under considerations.  See newspaper story "Draft rules aim at risks of logging on slopes."  

New developments:  On March 1 2002, an environmental group has filed suit against the Oregon Department of Forestry claming that the State Forest Practices Rules allow logging that harms endangered salmon through landslides.  See newspaper story "Suit against State Forester claims logging rules harm fish".  

   Clearcutting Causes Landslides:  A 1997 web page expressing the environmental viewpoint, from Umpqua Watersheds Inc., "a non profit organization dedicated to protecting and restoring the watersheds of the Umpqua River basin."   Lots of good photos.  20-30 minutes total reading time.

• The best piece on this page is "Aerial Landslide Survey of the Mapleton Ranger District" by AFSEE, an organization supporting environmental ethics among Forest Service Employees.  This article provides information on the relative numbers of landslides associated with clearcut lands, logging roads, and uncut forest lands.  Note that is is an aerial survey, and the aerial survey methodology has been strongly challenged as inadequate by the Oregon Department of Forestry.  The Mapleton District of the Siuslaw National Forest  is located due west of Eugene in the Coast Range.  

• Another good article is "Fact Sheet on Clearcuts, Landslides and the 1996 storm" a summary of a report by Pacific Rivers Council (another environmental organization).    

• Another good article that you can get to from this page is "Landslides and Clearcuts -- What does the science really say", by Doug Heiken.  This article summarizes a number of scientific studies on this question, and also explains the theories of why landsliding may be more common after clearcutting.  

• The first article, "Clearcut Landslides in Douglas County" is a good description, with photos, of an informal aerial observation of landslides and clearcuts in Dec. 1996, about 1 month after the events described above. 

• "Landslide Commentaries" presents some written and broadcast statements from mainline new media following the 1996 debris flows.  Only statements supporting the clearcut-landslide connection and critical of the Oregon department of Forestry are included, however.    

When the Oregon Legislature convened in January 1997, protecting citizens from landslide hazards was a hot topic.  After heated debate January through July, Senate Bill 1211 was finally passed in July at the very end of the legislative session.  Senate Bill 1211 authorized several studies by state agencies and the debris flow warning system by Oregon Dept. of Forestry.  This controversial bill was intended to be only an interim solution, and the legislature revisited the issue again in the 1999 session (see below).  

(The Oregon legislature meets only every other year -- it's interesting to speculate how legislation and policy might have been different if 1997 had not been a legislative year.)

These six stories are arranged in reverse order -- the end of the story is at the top.  Start at the bottom if you want to feel the building suspense!