HomeMy WebLinkAboutGeologic Assessment - GEO General - 7/30/2004 . GREEN DIAMOND Northwest Timberlands Division
RESOURCE COMPANY PO North Third St 98584-Shelton,Washington T eendi mond.81
PO Box 9001 98584-0931 greendiamond.com
RED D
July 30,2004
AA " Rr•n}
Pt
1
Michael MacSems
Mason County MCCp ,
P.O.Box 279
Shelton,WA 98584
Dear Michael,
Below is a Geologic Assessment for Green Diamonds proposed timber harvest in the S�/s of SW 1/4,Section
34,Township 21N,Range 3W,W.M.and the NW 1/4,Section 3,Township 20N,Range 3W,W.M..
INTRODUCTION
A field review was conducted on July IP,2004,by myself and Dave Backstrom,both with many years of
experience identifying potentially unstable slopes in a forested environment. We specifically inspected the
areas of concern expressed by Michael MacSems on the subject property.
DISCUSSION
Slopes in the 2 areas of concern vary between 10%to 25%maximum. No evidence of soil movement,or
cracks,or pistol-butted trees were found,indicating stable soil. Each site contained an old road(possibly a
skid road from first harvest),and inspection of the cut banks show that cuts across these relatively steeper
slopes remained stable and are now fully revegetated.
No signs of water were observed in the areas of concern. For the northern site,the nearest creek begins
more than 150 feet away from the toe of the slope. At both sites,the old road cut banks show no evidence
of intercepting ground water or wet-soil vegetation,and therefore no seeps or springs.
A review of the geologic map(Geologic Map of the South Half of the Shelton and South Half of the
Copalis Beach Quadrangles,Washington,by Logan, 1987)shows the subject property entirely within
"Vashon Outwash"geology. No contacts with other geologic units are on or near the subject property.
Visual inspection of the commercial gravel pit located within a mile of the site reveals no changes to
geology as well. Inspection of road cut banks in the area also shows similar and consistent geology in the
vicinity.
RESULTS
These sites do not meet Mason County requirements for classification as a"Landslide Hazard Area"in
17.01.00.A,because although slopes are greater than 15%in some areas,the other criteria(intersecting
geologic contacts and seeps/springs)are not present. Further,with no evidence of past mass soil
movement,and considering the field evidence,I believe these sites to be stable for harvest activities.
Sincerely,
(I SC N
As�MF��
Rick Schmeling,P.E. C ,�
Forest Engineer
Green Diamond Resource Company3518596
F
IONAL
gXPIRBS� � w
2,VD(v
MASON COUNTY Shelton (360) 427-9670
DEPARTMENT OF COMMUNITY DEVELOPMENT Belfair (360) 275-4467
Planning Mason County Bldg.1 41 t N.5th Elma (360) 482-5269
P.O.Box 279 Shelton,WA 98584
July 14, 2004
Dave Backstrom
Green Diamond Resource Co
P.O. Box 279
Shelton, WA 98584
Dear Dave;
My manager Bob Fink and I have reviewed your letter of July 7`hh in which you make
your case as to why a geo-technical assessment shouldn't be required on the Mason Lake
Road unit. We are willing to relax the requirement somewhat,but not entirely. In lieu of a
full assessment, we would accept a letter similar to the one you wrote if it is stamped by
someone with the credentials spelled out in section 17.01.100.E.3 of the Mason County
Resource Ordinance.
The problem in these situations is that while slopes are relatively easy to measure,
correctly interpreting geological data and identifying seeps during the dry season is not
always so easy. From a liability perspective the County wants a qualified individual to
make these determinations—especially in the less obvious cases such as this one.
If you have any questions please call me at ext. 571. Thank you.
Sincerely,
Michael MacSems
FPA Planner
AVGREEN DIAMOND Northwest Timberlands Division
RESOURCE COMPANY PO North Third St Shelto98584-,Washington T eendi428-3381
PO Box 9001 98584-0931 greendiamond.com
July 7, 2004
Michael MacSems
Mason County
P.O. Box 279
Shelton, WA 98584
Dear Michael;
In response to your e-mail of June 29,requesting that Green Diamond Resource
Company do a geo-tech assessment on part of our Mason Lake Rd harvest unit, I believe
that the two small areas of your concern do not meet the requirements of the Mason
County Resource Ordinance to be classified as a Landslide Hazard Area.
According to the Landslide Hazard Area classification criteria of 17.01.100 A.1.,none of
the situations listed are present within the proposed harvest area. Under Le., slopes must
be greater than 15% and have intersecting geologic contacts and have springs or seeps.
Slopes were measured up to 25% in your areas of concern, however the two other
requirements of Le. are not present. The underlying geology is consistently Vashon
Glacial drift and no signs of seeps or groundwater were observed.
The soils of this area are glacial "Everett" and "Carstairs" soils that are listed in the State
soil survey information from DNR as having a low potential for erosion and stable under
disturbed condition. The soils are deep as shown in the commercial gravel pit located
just to the south in the same soil type. Even if there were some soil movement, none of
the soil would move off site to an adjacent owner's property.
I don't believe that the areas of concern qualify as Landslide Hazard Areas and therefore
should not require a geo-tech assessment. Please call me at 427-4797 if you have further
questions or concerns.
incer�,
Dave Backstrom
Area Engineer
Green Diamond Resource Company
Michael MacSems Mason Lake Rd FPA Page 1
From: Michael MacSems
To: dbackstrom@greendiamond.com
Date: 6/29/04 2:40PM
Subject: Mason Lake Rd FPA
Dave,
I walked the Mason Lake Rd parcel yesterday(Monday, 6/28). Of course it is mostly flat, but the bowl on
the far western tip of the unit does trigger the geo-tech assessment requirements of Mason County
Resource Ordinance. In the checklist the slopes were listed as 15%, but I measured them in the low to
mid 20s. Per the Mason County Resource Ordinance, Landslide Hazard Chapter(17.01.100) 1 need to ask
you for a geo-tech assessment for the bowl portion of the unit. Although I didn't measure it, I think that the
south slope of the most easterly Leave Area is of a similar percentage, could you have your qualified
professional check that out too?
The specification for a geo-tech assessment(as opposed to a full report)can be found in section
17.01.100.E.4. and the qualification of the assessment preparer is in section 17.01.100.E.3. These can be
found on line- but if you can't find them, let me know your fax number and I will send them to you that
way.
When I receive the geo-tech assessment I will review if for completeness and forward it to Alan Tahja in
the Engineer's office for approval. That review will cost$39.22 an hour (usually takes an hour).
Other than that I didn't see anything else of concern on the unit. I did notice that the larger Leave Area on
the far west of the unit does sit above a tributary to John's Creek, but it appears that all of your activity will
meet Fish &Wildlife Habitat setbacks.
If you have any questions please e-mail me or call me at 427-9670 x571.
Thanks,
Michael MacSems
CC: MacSems, Michael