HomeMy WebLinkAboutSEP2007-00012 - SEP Determinations - 2/27/2007 P�oN.SrgTFo� MASON COUNTY
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DEPARTMENT F COMMUNITY DEVELOPMENT
o A° = tanning Division
r o T z PO ox 279, Shelton,WA 98584
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1864
MITIGATE
DETERMINATION OF NON SIGNIFICANCE
(WAC 197-11- 50)
SEP2007-00012
Description of Proposal: Mason County PublicWorks: This SEPA determination (Phase 1
of 2) is associated wit i a logging permit (FPA 2007-00002)for two
units totaling 13.5 acres of an approximately 70-acre site. The
purpose of the logging is for the construction of a new Public
Works facility for which a separate SEPA determination (phase 2
of 2) shall follow within 14 days. The site was reviewed for
Pileated Woodpecker and Shelton Pocket Gopher habitat. No
Pocket Gopher habitat was found but one Pileated forge tree was
found as well as two additional snags with forage potential. The
snags will be left intact, except for the active forage snag, which
may or may not have to be relocated to a green buffer on the
edge of the cutting unit. A slope between 15 and 40% is located
within 300 feet of the.northern most cut and a geo-technical
assessment was reviewed and approved by Robert Tauscher,
P.E. of City of Shelton Public Works. A temporary stormwater plan
for the logging phase was reviewed and approved by Aspect
Consulting. Both the development and the final stormwater plan
will be reviewed through the Phase 2 SEPA determination."
Proponent: MASON COUNTY PUBLIC WORKS
Site Address (If Assigned): ...............
Directions to Site: NORTH ON US 101 TO SR 102, SITE ENTRANCE +/- 1600FEET
NORTH OF SR 102 DN WEST SIDE OF US 101
Parcel Number: 420022100000
Legal Description: NE NW PCL 1 OF B A #01-75
Lead Agency: Mason County
The Lead Agency for this proposal has determined that it does not have a probable significant
adverse impact on the environment. An Environmental Impact Statement (EIS) is not required
under RCW 43.21 C.030(2)(c). This decision was made after review of a completed
Environmental Checklist and other information on file with the Lead Agency. This information is
available to the public upon request. MITIGATED MEASURES ARE ATTACHED.
Please contact Michael MacSems at ext. 571 with any questions. This DNS is issued under
WAC 197-11-340(2). The Lead Agency will not act o this proposal for 14 days from the date
shown below, when the determination is final. Comments must be submitted to Dept. of
Community Development, P.O. Box 279, Shelton WA 98584 by 3/13/2007. Appeal of this
determination must be filed within a 14-day period following this final determination date, per
Mason County Code Chapter 15.11 Appeals.
Authorized Local Government Official Date
MITIGATED
DETERMINATION OF NONSIGNIFICANCE
(WAC 197-11-350)
SEP2007-00012
CONDITIONS OF THIS DE ERMINATION
1) Pileated Woodpecker Snag Management
Three snags that are potential Pileated woodpecker forage habitat have been identified on
this site. Two are large remnants of the previous stand of timber that grew in the area and
one is a small tree approximately 12" DBH and 70' tall. The small tree shows evidence of
recent woodpecker foraging. The other two do not.
Absent any safety issues identified by the Washington Department of Labor and Industries,
all three will be left standing following logging. Of the three snags, the small tree has the
most likely potential for generating a safety issue. If it needs to be cut, it will be bucked to
a length of 20-24 feet and relocated to the edge of the logging unit. A hole would then be
dug in the ground and the snag segment would be placed in the hole and left in a standing
position. If the tree is too decayed to remain intact when it is felled, a similar size stem
would be selected from the logging area and relocated on the edge of the logging unit to
replace the original snag.
X
2) STORMWATER & EROSION CONTROL MEAOURES
Escape of silty water or mud from the timber harvest area shall be considered a violation of
County and State stormwater management regulations, and could subject the applicant(s)
to civil fines or penalties.
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Section 2, Twp. 20 north, Rge. 4 west, WM Scale: 1"=240 feet
X----X---X = Cutting boundary Contour Interval = 1 foot
TO BE COMPLETED BY APPLICANT: EVALUATION FOR
AGENCY USE ONLY
A. BACKGROUND
1. Name of proposed project, if applicable:
Mason County Public Works Office Site Logging.
2. Name of applicant:
Mason County Department of Public Works.
3.Address and phone number of applicant and contact person:
Attn: Rick Hirschberg
Mason County
Department of Public Works
P.O. Box 1850
Shelton,WA 98584
Telephone: (360)427-9670 ext.748
4. Date checklist prepared:
January 9, 2007
5.Agency requesting checklist:
Mason County Department of Community Development.
6. Proposed timing or schedule (including phasing, if applicable):
Logging is proposed for early spring, 2007.
7. Do you have any plans for future expansion, or further activity related to or connected with this proposal? If yes
explain.
The new Public Works office complex will be constructed on the site following logging and clearing.
8. List any environmental information you know about that has been prepared, or will be prepared, directly
related to this proposal.
A SEPA checklist was prepared for the construction of the new office complex.
9. Do you know whether applications are pending for governmental approvals of other proposals directly
affecting the property covered by your proposal? If yes, explain.
None known.
10. List any government approvals or permits that will be needed for your proposal, if known.
Mason County®Building permit, Mason Environmental permit.
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TO BE COMPLETED BY APPLICANT: EVALUATION FOR
AGENCY USE ONLY
11.Give a brief, complete description of your proposal, including the proposed uses and the size of the project and site.
There are several questions later in this checklist that ask you to describe certain aspects of your proposal. You do
not need to repeat those answers on this page. (Lead agencies may modify this form to include additional specific
information on project description.)
Clearcut all merchantable timber on office site as shown on attached exhibit.
12.What is the location of the proposal. Give sufficient information for a person to understand the precise location of
your proposed project, including a street address, if any, and section,township, and range, if known. If a proposal
would occur over a range of area, provide the range or boundaries of the site(s). Provide a legal description, site
plan,vicinity map, and topographic map, if reasonably available. While you should submit any plans required by
the agency,you are not required to duplicate maps or detailed plans submitted with any permit applications related
to this checklist.
From Shelton,travel north on State Highway 101 2 1/4 miles to the intersection with a previously
constructed logging road on the left. The old logging road enters the southern 1/3 of the logging unit.
B. ENVIRONMENTAL ELEMENTS:
1. EARTH:
a. General description of the site (circle one : flat. olling, hilly, steep slopes, mountainous, other
b. What is the steepest slope on the site (approximate percent slope)? 2%.
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c. What general types of soils are found on the site(for example, clay, sand, gravel, peat, muck)? If you know the
classification of agricultural soils, specify them and note any prime farmland.
The Mason County soil survey lists these soils as Grove, gravelly,sandy loam.
d. Are there surface indications or history of unstable soils in the immediate vicinity? If so, describe.
No.
e. Describe the purpose,type, and approximate quantities of any filling or grading proposed. Indicate source of
fill.
f. None proposed.
f. Could erosion occur as a result of clearing, construction, or use? If so, generally describe.
None likely. The area is flat with an extremely permeable soil.
g. About what percent of the site will be covered with impervious surfaces after project constructions (for example,
asphalt or buildings)?
No new impermeable surfaces will be created.
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TO BE COMPLETED BY APPLICANT : EVALUATION FOR
AGENCY USE ONLY
h. Proposed measures to reduce or control erosion, or other impacts to the earth, if any: Nees one✓e c;� ►�S
Compliance with BMPs as prescribed in Forest Practice Rules. 1��e 1 �Prr'_�4
0_519-�07_4 CCAAstJ�t
2.AIR:
a. What types of emissions to the air would result from the proposal (i.e.dust,automobile, odors,
industrial wood smoke) during construction and when the project is completed? If any, generally
describe and give approximate quantities, if known.
The primary emission would be equipment exhaust.
b. Are there any off-site sources of emissions or odor that may affect your proposal? If so, generally describe.
None known.
c. Proposed measures to reduce or control emissions or other impacts to air, if any:
None proposed.
3.WATER:
a. Surface:
1) Is there any surface water body on or in the immediate vicinity of the site(including year-round and
seasonal streams, saltwater, lakes, ponds,wetlands)? If yes, describe type and provide names. If
appropriate, state what stream or river it flows into.
No surface waters exist in the immediate vicinity.
2)Will the project require any work over, in, or adjacent to(within 200 feet)the
described waters? If yes, please describe and attach available plans.
No.
3) Estimate the amount of fill and dredge material that would be placed in or removed from surface water or
wetlands and indicate the area of the site that would be affected. Indicate the source of fill material.
NA
4)Will the proposal require surface water withdrawals or diversions? Give general description, purpose,
and approximate quantities if known.
No.
5) Does the proposal lie within a 100-year floodplain? If so, note location on the site plan
No.
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TO BE COMPLETED BY APPLICANT: EVALUATION FOR
AGENCY USE ONLY
6) Does the proposal involve any discharges of waste materials to surface waters? If so,
describe the type of waste and anticipated volume of discharge.
No.
b. Ground:
1)Will ground water be withdrawn, or will water be discharged to ground water? Give general
description, purpose, and approximate quantities, if known.
No.
2) Describe waste material that will be discharged into the ground from septic tanks or other sources, if
any(for example, Domestic sewage: industrial, agricultural, etc.). Describe the general size of the
system,the number of such systems,the number of houses to be served (if applicable), or the number of
animals or humans the system(s)are expected to serve.
Not applicable.
c. Water Runoff(including storm water):
1) Describe the source of runoff(including storm water)and method of collection and disposal, if any
(include quantities, if known). Where will this water flow? Will this water flow into other waters? If so,
describe.
Rain/storm water is, in general, the only source of runoff. It will infiltrate into the ground on-site.
2) Could waste materials enter ground or surface waters? If so, generally describe.
Possible gas, oil or diesel spillage during equipment maintenance and operation.
d. Proposed measures to reduce or control surface,ground, and runoff water impacts, if any:
Contractor will be required to have a spill containment kit on-site.
4. PLANTS:
a. Check or circle types of vegetation found on the site:
_deciduous tree: alder, maple, aspen,other
✓evergreen tree: fir, cedar, pine, other
,(shrubs
✓ grass
pasture
crop or grain
_wet soil plants: cattail, buttercup, bulrush, skunk cabbage, others
_water plants: water lily, eelgrass, milfoil, other
®other types of vegetation:
b. What kind and amount of vegetation will be removed or altered?
Approximately 12 acres of second-growth timber will be clearcut.
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TO BE COMPLETED BY APPLICANT: EVALUATION FOR
AGENCY USE ONLY
c. List threatened or endangered species known to be on or near the site.
None known. -�
d. Proposed landscaping, use of native plants, or other measures to preserve or enhance vegetation on
the site, if any:
None proposed.
5.ANIMALS
a. Circle any birds and animals which have been observed on or near the site or are known to be on or
near the site:
birds: hawk, heron, eagle, songbirds, other: All are possible
mammals: deer, bear, elk, beaver, other All possible except elk and beaver
fish: bass, salmon,trout, herring, shellfish, other No fish are present y
b. List any threatened or endangered species known to be on or near the site.
None.
c. Is the site part of a migration route? If so, explain
Highly unlikely.
d. Proposed measures to preserved or enhance wildlife, if any:
None proposed.
6. ENERGY AND NATURAL RESOURCES:
a. What kinds of energy(electric, natural gas, oil,wood stove, solar)will be used to meet the completed
project's energy needs? Describe whether it will be used for heating, manufacturing, etc.
None required.
b. Would your project affect the potential use of solar energy by adjacent properties? If so, generally
describe.
No.
c. What kinds of energy conservation features are included in the plans of this proposal? List other
proposed measures to reduce or control energy impacts, if any:
None .
7. ENVIRONMENTAL HEALTH:
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TO BE COMPLETED BY APPLICANT : EVALUATION FOR
AGENCY USE ONLY
a. Are there any environmental health hazards, including exposure to toxic chemicals, risk of fire and
explosion, spill,or hazardous waste,that could occur as a result of this proposal? If so, describe.
Only those associated with refueling operating and servicing the logging equipment.
1) Describe special emergency services that might be required.
Emergency medical in case of an accident.
2) Proposed measures to reduce or control environmental health hazards, if any:
Normal logging safety practices as prescribed by the Department of Labor and Industries.
b. Noise.
1)What types of noise exist in the area which may affect your project(for example: traffic, equipment
operation, other)?
None.
2)What types and levels of noise would be created by or associated with the project on a short-term
or a long-term basis(for example: traffic, construction, and operation, other)? Indicate what hours
noise would come from the site
Normal noise from logging equipment. Logging activity will
be restricted to daylight hours.
3) Proposed measures to reduce or control noise impacts, if any:
Mufflers standard on equipment. Restrict work to daylight hours only.
8. LAND AND SHORELINE USE:
a. What is the current use of the site and adjacent properties?
Timber production.
b. Has the site been used for agriculture? If so, describe.
No.
c. Describe any structures on the site.
None.
d. Will any structures be demolished? If so,what?
No.
e. What is the current zoning classification of the site?
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TO BE COMPLETED BY APPLICANT: EVALUATION FOR
AGENCY USE ONLY
No county zoning.
f. What is the current comprehensive plan designation of the site?
GMA
g. If applicable,what is the current shoreline master program designation of the site?
NA
h. Has any part of the site been classified as an"environmentally sensitive"area? If so, specify.
No.
i. Approximately how many people would reside or work in the completed project? r+ '
None.
j. Approximately how many people would the completed project displace?
None.
k. Proposed measures to avoid or reduce displacement impacts, if any:
None applicable.
I. Proposed measures to ensure the proposal is compatible with existing and projected land uses and
plans, if any:
Project is in preparation for construction of an office and shop complex.
9. HOUSING:
a. Approximately how many units would be provided, if any? Indicate whether high, middle, or low-
income housing.
None.
b. Approximately how many units, if any,would be eliminated? Indicate whether high, middle,or low-
income housing.
None.
c. Proposed measures to reduce or control housing impacts, if any:
None.
10.AESTHETICS:
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TO BE COMPLETED BY APPLICANT : EVALUATION FOR
AGENCY USE ONLY
a. What is the tallest height of any proposed structure(s), not including antennas;what is the principal
exterior building material(s) proposed?
None proposed.
b. What views in the immediate vicinity would be altered or obstructed?
They will be improved by removing the existing timber.
c. Proposed measures to reduce or control aesthetic impacts, if any:
Several areas will be left uncut. Refer to attached map.
11. LIGHT AND GLARE
a. What type of light or glare will the proposal produce? What time of day would it mainly occur?
None.
b. Could light or glare from the finished project be a safety hazard or interfere with views?
No.
c. What existing off-site sources of light or glare may affect your proposal:
None.
d. Proposed measures to reduce or control light and glare impacts, if any:
None.
a. What designated and informal recreational opportunities are in the immediate vicinity?
None.
b. Would the proposed project displace any existing recreational uses? If so, describe.
No.
c. Proposed measures to reduce or control impacts on recreation, including recreation opportunities to
be provided by the project or applicant, if any:
None applicable.
13. HISTORIC AND CULTURAL PRESERVATION:
a. Are there any places or objects listed on, or proposed for, national, state, or local preservation
registers known to be on or next to the site? If so, generally describe.
None are known.
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TO BE COMPLETED BY APPLICANT: EVALUATION FOR
AGENCY USE ONLY
b. Generally describe any landmarks or evidence of historic, archaeological, scientific,or cultural
importance known to be on or next to the site.
None known.
c. Proposed measures to reduce or control impacts, if any:
None.
14.TRANSPORTATION:
a. Identify public streets and highways serving the site and describe proposed access to the existing
street system. Show on site plans, if any.
State Highway 101. I� I u
b. Is site currently served by public transit? If not,what is the approximate distance to the existing street
system. Show on site plans, if any.
��ti,SO� Cv 1Uw,�t 1 • �
No.
c. How many parking spaces would the completed project have? How many would the project
eliminate?
None.
d. Will the proposal require any new roads or streets, or improvements to existing roads or streets, not
including driveways? If so, generally describe (indicate whether public or private).
No.
e. Will the project use (or occur in the immediate vicinity of)water, rail, or air transportation? If so,
generally describe.
No.
f. How many vehicular trips per day would be generated by the completed project? If known, indicate
when peak volumes would occur.
The project would not change the existing level of vehicular traffic.
g. Proposed measures to reduce or control transportation impacts, if any:
None.
15. PUBLIC SERVICES:
a. Would the project result in an increased need for public service(for example: fire protection, police
protection, health care, schools, other)? If so, generally describe:
No
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TO BE COMPLETED BY APPLICANT : EVALUATION FOR
AGENCY USE ONLY
b. Proposed measures to reduce or control direct impacts on public services, if any:
None.
16. UTILITIES:
a. Circle utilities currently available at the site: electricity, natural gas,water, refuse service,telephone,
sanitary sewer, septic system, other:
Telephone and electricity.
b. Describe the utilities that are proposed for the project,th utility providing the service, and the general
construction activities on the site or in the immediate vici�ity which might be needed:
None.
17.SIGNATURE:
The above answers are true and complete to the best of my knowledge. I understand that the
lead agency is relying^on them to make its decision.
Signature: ' Da t Submitted r /'7 I7
10101010
ESA LISTED SALMONIDS CHECKLIST
Applicant Information Proiect Information
Date: January 17,2007
Name: Mason County Department of Public Works Name: Public Works Office Site Logging
Phone: (360)427-9670 ext.748 Location: Sec. 2,Twp.20 north,Rge. 4 west
WM
Attn: Rick Hirschberg Description: Log approximately 12 acres
This worksheet was designed to help project proponents and government agencies identify when a
project needs further analysis regarding adverse effects on ESA(Endangered Species Act) listed
salmonids are salmon,trout and chars, e.g. bull trout. For our purposes,"ESA listed salmonids" is
defined as fish species listed as endangered,threatened or being considered for listing.
If ESA listed species are present or ever were present in the watershed where your project will
be located,your project has the potential for affecting them,and you need to comply with the
ESA. The question in this section will help determine if the ESA listings will impact your
project.
The Fish Program Manager at the appropriate Department of Fish and Wildlife(DFW)regional office can provide information for the
following two questions
1. Are ESA listed salmonids currently present in the watershed in which your project will be
located?
Yes-No X
Please describe:
2. Has there ever been an ESA listed salmonid stock present in this watershed?
Yes No X Uncertain
Please describe:
If you answered "yes"to either of the above questions,you should complete the remainder of
this checklist.
PROJECT SPECIFICS: The questions in this section are specific to the project and vicinity.
1. Name of Watershed:
2.Name of nearest waterbody:
3. What is the distance from this project to the nearest body of water?
Often a buffer between the project and a stream can reduce the chance of a negative impact to
fish.
Mason County Shoreline Permit Supplement Page 1
4. What is the current land use between the project and the potentially affected waterbody(parking
lots, farmland, etc.)? The current use at the project site is a county road and bridge.
5. Is the project above a:
• natural permanent barrier(waterfall)? Yes No
• natural temporary barrier(beaver pond)? Yes No
• man-made barrier(culvert, dam)? Yes No
• other(explain) :
6. If yes to any of the above, are there any resident salmonid populations above the blockage?
7. What percentage of the project will be impervious surface(including pavement&roof area)?
The project will increase the impervious surface by 42%. This is due to increasing the paved
running surface of the road five feet on each side for a distance of 800 feet.
FISH MIGRATION° The following questions will help determine if this project could interfere
with migration of adult and juvenile fish.
Both increases and decreases in water flows can affect fish migration.
1. Does the project require the withdrawal of:
i. Surface water? Yes No _
Amount
Name of surface waterbody.
it. Ground water: Yes No _
Amount
From where
Depth of well
2. Will any water be rerouted?
Yes No
If yes, will this require a channel change?
3. Will there be retention or detention ponds?
Yes No
If yes,will this be an infiltration pond or a surface discharge to either a municipal storm water
system or a surface waterbody?
If to a surface water discharge, please give the name of the waterbody:
Mason County Shoreline Permit Supplement Page 2
4. Will this project require the building of new roads?
Yes No . Increased road mileage may affect the timing of water reaching a stream
and may impact fish habitat.
The only road construction will be that needed to widen the existing road to meet current County
design standards.
5. Are culverts proposed as part of this project?
Yes No
6. Will topography changes affect the duration/direction of runoff flows?
Yes No
If yes, describe the changes.
7. Will the project involve any reduction of the floodway or floodplain by filling or other partial
blockage of flows?
Yes No
If yes, how will the loss of flood storage be mitigated by your project?
WATER QUALITY: The following questions will help determine if this project could
adversely affect water quality. Such adverse affects can cause problems for listed species.
Water quality can be made worse by runoff from impervious surfaces,altering water temperature,discharging contaminants,etc.
1. Do you know of any problems with water quality in any of the streams within this watershed?
Yes No—
If yes, describe:
2. Will your project either reduce or increase shade along or over a waterbody?
Removal of shading vegetation or the building of structures such as docks or floats often result in a change in shade.
Yes No There will be a slight increase in shade over the stream because the new
bridge is ten feet wider than the old one and is oriented east-west.
3. Will the project increase nutrient loading or have the potential to increase nutrient loading or
contaminants(fertilizers, other waste discharges, or runoff)to the waterbody?
Yes No—
4. Will turbidity be increased because of construction of the project or during operation of the
project? In-water or near water work will often increase turbidity.
Yes No . The only in-water work is removal of two existing piers. This will be done
during low tide periods when there is no water in the work area..
5. Will your project require ling-term maintenance, i.e.,bridge cleaning, highway salting, chemical
sprays for vegetation management, clearing of parking lots?
Yes_ No . Likely only de-icing chemicals on the road and bridge deck..
Mason County Shoreline Permit Supplement Page 3
If yes,please describe:
VEGETATION: The following questions are designed to determine is the project will affect
riparian vegetation,thereby,adversely impacting salmon.
1. Will the project involve the removal of any vegetation from the stream banks?
Yes_ No
If yes,please describe the existing conditions, and the amount and type of vegetation to be
removed. Widening of the road approaches to the new bridge will remove several conifers.
2. If any vegetation is removed, do you plan to re-plant?
Yes No
If yes,what types of plants will you use?
Mason County Shoreline Permit Supplement Page 4
Aspectconsulting
IN-DEPTH PERSPECTIVE
January 22, 2007
Mason County Department of Public Works
415 N 6th Street
Shelton, Washington 98584
Attention: Bob Thuring
Re: Geological Assessment
Proposed Public Works Facility
U.S. 101 & State Road 102
Mason County, Washington
Project No. 060159-005-01
Reference: Subsurface Exploration, Geolog c Hazard and Geotechnical Engineering
Report, Proposed Mason County Public Works Facility, Highway 101, Mason County,
Washington, Aspect Consulting, January 22,2007
Dear Mr. Thuring:
This letter summarizes our field notes and conclusions regarding the nature of the site slopes
with respect to the proposed development. Geotec ical design recommendations for the
proposed development are'shown separately in our above-referenced geotechnical report. A
geologic slope reconnaissance of the site slopes and subsurface exploration in the proposed
i
construction areas were performed.
Project Understanding
The project site consists of an undeveloped lot no th of the intersection of State Road 102 and
U.S.Route 101 in Mason County. The project consists of construction of a new Mason County
Department of Public Word s(MCDPW)maintenance and office facility with a fueling station
and associated parking areas at the site. The locati n of the site is presented on Figure 1,Site
Location Map.
Observations
Site Conditions and Topography
The site is essentially flat,with a slope at the northwest corner of the property. The slope is
approximately 50 feet in height. Overall the slope angle was on the order of 4H:1 V
(Horizontal:Vertical), or 25 percent steepness. Mid-slope was a 20 foot high steeper zone that
was at approximately 2.5H':IV, or 40 percent steepness. The south face of the slope to the west
of the project area was reportedly the excavated face of a relict gravel pit. The site area is
shown on Figure 2,Site and Exploration Plan.
The slopes at the site are approximately 40 percent steepness and have greater than 10 feet of
vertical relief,thus meeting the Landslide Hazard Area criteria as defined in the Mason County
Mason County Department of Public Works
January 22, 2007 Project No. 060159-005-01
Resource Ordinance. As a result,the restrictions aid requirements as outlined by the code
apply to development of the site.
Drainage
Drainage on the property was generally diffuse, with no evidence of concentrated flow. We
observed no evidence of groundwater seepage in the site slopes or in the exploration pits
performed for the geotechnical evaluation of the site.
Vegetation
Vegetation on the slopes consisted primarily of small fir trees and a heavy understory of salal,
berry bushes and small shrubs.
Geology
Subsurface conditions on the slope were inferred from a visual reconnaissance of the site and
review of applicable geologic literature. Soil exposed in the excavated face consisted of dense
to very dense, reddish-brown to brown, slightly silty sand, gravel and cobbles, interpreted as
intact glacial till deposits. Soils exposed in the subsurface exploration consisted primarily of
clean,sandy gravel, interpreted as glacial outwash deposits. The soils observed at the site
match the strata mapped as Pleistocene glacial till nd proglacial outwash on the Washington
State DNR Geologic Map of the Shelton 1:100,00 Quadrangle, Washington. These strata
were deposited during the most recent glaciation, which locally occurred between about 13,000
and 16,000 years ago and were subsequently overridden by the glacial ice sheet. These strata
have been compressed by thousands of feet of glacial ice. As a result of this compression, the
soil exhibits low compressibility and high strength characteristics. These strata are suitable for
any required foundation or retaining wall support, provided the recommendations in the above-
referenced geotechnical report are properly followed and implemented.
Hydrology
No groundwater seepage or, groundwater was observed within the slope or within the
exploration pits at the subject property.
It should be noted that fluctuations in the level of groundwater may occur due.to time of year,
variations in site usage,rainfall, irrigation, and other factors.
Slope Stability
Three types of slope failures are prevalent on slop s in the Puget Sound area. Shallow debris or
colluvial landslides usually involve failure of a thi skin of loose and weathered soil and
vegetation that mantles steep slopes. Failure usually consists of the colluvial layers sliding or
flowing over the dense or hard,undisturbed soils.Tbe region's second most common type of
landslide failure is a rotational or deep-seated Ian Tide failure. This type involves rotation of a
mass of soils along a bowl-shaped or curved failure plane. This type of failure often results in
movement of large blocks of relatively intact soils The third type of failure consists of
toppling or spalling of blocks of relatively intact soils from a bluff that has been undermined
by erosion. These blocks typically fail along high angle (typically near vertical) fractures
present in the soil units.
Page 2
Mason County Department of Public Works
January 22, 2007 Project No. 060159-005-01
We observed no evidence of active, recent or incipient slope instability of any of these types on
the site slope.
If slope and runoff conditions change (i.e., extensive clearing of vegetation at the site or
concentration of stormwater) in an adverse mannel during or after construction, the potential
for slope erosion and slide activity could increase.
Seismic Design Considerations
The nearest known active fault to the project site is the Tacoma fault. The western end of this
fault lies about 10 miles to the northeast of the site This recently identified fault zone extends
at least 30 miles from near the southeastern tip of Ilood Canal to the Tacoma and Federal Way
area. The U.S. Geological Survey reports that the Tacoma Fault may have caused a shallow
earthquake of 7 to 7.5 magnitude 1,100 years ago nd caused about 12 feet of uplift along areas
of the Tacoma Fault(Sherrod, B.L, and others, 2003, The Catfish Lake Scarp,Allyn,
Washington: Preliminary Field Data and Implicat ons for Earthquake Hazards Posed by the
Tacoma Fault,U.S. Geological Survey Open-File Report 03-0455). The U.S. Geological
Survey believes that the Tacoma fault may be a no h-dipping back-thrust to the Seattle fault
(discussed below), so that slip on a master thrust fault at depth could result in movement on the
Seattle fault,the Tacoma fault, or both. Informatio ri on potential seismicity associated with the
Tacoma fault has not been published in agency documents. It is not possible to fully evaluate
the hazards from this structure until a code-based rsource of potential earthquake information is
available.As research continues regarding the seismic hazards in the Puget Sound region, other
suspected fault systems will likely be identified.
We presume that any future proposed structures at the site would be constructed under the
provisions of the 2003 International Building Cod (IBC). For seismic site design purposes, the
soil classification for this site would be Site Class , and a peak ground acceleration of 0.33g
may be used as determined by Chapters 16 and 18 of the 2003 IBC.
Conclusions and Recommendations
From a geotechnical perspective, the site slopes dc not present a landslide hazard to the
proposed development. The nearest proposed structure is approximately 150 feet away from
the toe of the slope. The slopes have sufficient run ut space that surficial slide debris, if it were
to occur,would not reach the proposed structures. The site slopes and proposed structure
locations are shown on Figure 2.
Soils in the site slope consist of very dense, slightly silty, sand, gravel and cobbles.The site
topographic, soil, and surface and groundwater characteristics suggest that,under existing
conditions,the site has a low potential for additional slope instability. If seepage,runoff,or
stormwater flow were to increase significantly,erosion of the soils on the slope and the chance
of landslides could increase. Similarly, improper hillside grading, extensive upland clearing, or
poor stormwater handling practices could increase the risk of slope instability.
Based on the general slope configuration, deep-seated seismic sliding under this design basis is
considered a low risk. The most likely impact tot e property from a slope stability perspective
would be shallow debris landslides as a result of saturation of the near-surface,weathered soils
on the slope. Slides of this type are typically limited to the weathered soil unit within the upper
Page 3
Mason County Department of Public Works
January 22, 2007 Project No. 060159-005-01
2 to 3 feet and typically do not have a significant effect on the underlying geologic units.
Factors that affect slope instability within the near-surface, weathered soil layer include the
following(D.H. Gray and A.T. Leiser, Biotechnical Slope Protection and Erosion Control:
Van Nostrand Reinhold,New York, 1982):
Root Reinforcement:
Roots mechanically reinforce a soil by transfer of shear stresses in the soil to tensile
resistance in the roots.
Soil Moisture Modification:
Evapotranspiration and interception in the foliage limit build-up of soil moisture.
Buttressing and Arching:
Anchored and embedded stems can act as buttress piles or arch abutments in a slope,
counteracting shear stresses.
Surcharge:
Weight of vegetation on a slope exerts both a downslope (destabilizing) stress and a
stress component perpendicular to the slope, which tends to increase resistance to
sliding.
Root Wedging:
Tendency of roots to invade cracks, fissures, and channels in a soil or rock mass and
thereby cause local instability by a wedging or prying action.
Windthrowing:
Destabilizing influences from turning moment exerted on a slope as a result of strong
winds blowing downslope through trees.
Root reinforcement, soil moisture modification (reduction), and buttressing and arching have a
net enhancing effect on slope stability at the site. Surcharge, root wedging and windthrowing
will have a net destabilizing effect. Other sources of surficial slope instability include
improperly managed storm and surface water runoff flowing near or over the top of the slope.
Surface vegetation should not be removed on the steep slopes. The intact slopes should not
only remain substantially covered with native vegetation, can be enhanced by planting on any
bared slope faces.
Proper long-term management of sloped areas will reduce the risk of possible future landslide
activity. Consequently, we recommend considering implementation of a long-term vegetation
management plan for the site.Excellent information on this subject is available in Washington
State Department of Ecology publications,Slope Stabilization and Erosion Control Using
Vegetation (publication 93-30) and Vegetation Management:A Guide for Puget Sound Slope
Property Owners (publication 93-3 1).
Page 4
Mason County Department of Public Works
January 22, 2007 Project No. 060159-005-01
Limitations
This letter has been prepared for the exclusive use of Mason County Department of Public
Works and their agents for specific application to this project. Within the limitations of scope,
schedule and budget, our services have been performed in accordance with generally accepted
geotechnical engineering and engineering geology practices in effect in this area at the time
our letter was prepared. This report is not a legal opinion and there is no other warranty,
expressed or implied. Our observations, findings, and opinions are a means to identify and
reduce inherent risks to the owner.
Thank you for the opportunity to provide these services to you. If you have any questions,
please do not hesitate to call Andy at (206) 780-7717 or John at (206) 780-7720.
Sincerely,
Aspect consulting, LLC
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James A. Peterson, PE John L. Peterson, PE
Project Geotechnical Engineer Associate Geotechnical Engineer
apeterson@aspectconsulting.com jpeterson@aspectconsulting.com
Attachments: Figure 1 —Site Location Map
Figure 2— Site and Exploration Plan
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TOGETHER'
February 15, 2007
Mr. Michael MacSems, FPA Planner
Mason County, Department of Community Development
Mason County Bldg. 1, 411 N. 5" Street
P.O. Box 279
Shelton,WA 98584
Dear Mr. MacSems:
Subject: Mason County Proposed Public Works Facility, Geo-technical Review Comments
Per your request to review the geo-technical assessme t and supporting documents provide for
the referenced project, received February 14, 2006, the following are my comments:
Mason County Ordinance Reference
1. Mason County Resource Ordinance, 17.01.100.A.1.
Site Description
2. The site is essentially flat, with a slope at the northwest corner of the property. The
northwest corner of property has a mid slope, 20 feet high which is approximately 2.5H:IV,
or 40 percent steepness.
3. The nearest proposed structure is approximately 150 feet from the toe of the slope.
4. There is no evidence of any concentrated drainage flow on the site.
5. No groundwater was observed in the exploration pits or on the property.
Comments
6. Per Mason County Resource Ordinance, 17.01.10 .E.1, Category a, the development
proposed is within 300 feet pf slopes greater than 0 percent and requires a Geotechnical
Report.
7. The Geotechnical Assessment submitted January 2, 2007 does not provide
recommendations whether a Geotechnical Report 3hould be required to further evaluate the
site; and does not provide delineation of the buffers and setbacks per section 17.01.100.E.4.
(7) &(8).
Recommendation:
I recommend you request supplemental information to address the above listed items#7 and
require a Geotechnical Report. The Subsurface Explo ation, Geologic Hazard and Geotechnical
525 W. Cota St. • Shel on, WA 98584
(360) 426-4491 *FAX (360) 426-1338 • -Mail: cityhall@ci.shelton.wa.us
Web Site: www.ci.shelton.wa.us
Engineering Report, Highway 101 Facility, dated January 22, 2007 has some of the required
information for a Geotechnical Deport,but does not include all thirteen elements.
As requested, attached is a breakdown of associated costs for the review. If you have any
questions,please feel free to contact me at (360) 432-5127.
Sincerely,
Robert E. Tauscher, P.E.
Project Engineer
RET:cr
F:\Engineering\Bob\Development\Mason County ProjectsWason County PW Sh p\0215077 Geotechnical Assessment Review.doc
�6°N oO°� MASON COUNTY
� ap DEPARTMENT OF COMMUNITY DEVELOPMENT Shelton (360) 427-9670
Belfair (360) 275-4467
Planning
_ Mason County Bldg. 1 411 N.5th Elma (360) 482-5269
P.O.Box 279 Shelton,WA 98584
>85A
Rick Hirschberg
Mason County Public Works
P.O. Box 1850
Shelton, WA 98584
January 25, 2007
Re: 42002-10-00010, 00020 &21-00000
Dear Mr. Hirschberg,
Today I visited the above referenced property to inspect it for your forest practice
application. While the site at first appears to be an easy review, there are a couple of
critical area issues that need to be dealt with before I can issue a SEPA DNS or MDNS.
These are Pileated Woodpecker habitat and steep slopes. I will address these topics in
more detail below:
Woodpeckers:
The Fish&Wildlife Habitat section(17.01.110) of the County's Critical Areas
Ordinance protects Pileated Woodpeckers. On site I observed a number of snags that
showing evidence of woodpecker foraging. Of these snags, I noted two (both south of the
existing road but most likely within the cutting unit) that showed evidence of recent
Pileated Woodpecker foraging. These snags, and any others like them, need to be
protected or their habitat value mitigated for if protection is not possible.
Dealing with protected snags can be perplexing as our code tells us to protect the habitat
and the Department of Labor & Industries tells us not to create hazardous situations for
the logging crew. One possible way to meet both requirements is to leave a stand of
healthy trees around the snag. However, when removal of such snags is unavoidable,
such snags can be removed with a Mason Environmental Permit (MEP) and a Habitat
Management Plan (HMP).
While I did not see any indications of Shelton Pocket Gophers on site, you should be
aware that they are on the list of protected species and are known to dwell within a mile
or so of this property. One of the parcels adjacent to this property is currently under
review for a commercial short subdivision. One of the SEPA comments I received after I
issued their MDNS was concern that the project would impact the pocket gophers. The
applicant is now having a study done, but I have not received it yet. You should be
prepared for the possibility that when SEPA is issued for this project that same issue may
be raised again. If you would like contact information for the adjacent property owner's
agent, I can provide it.
Slopes:
Your site plan shows that steep slopes exist as close as 200 feet from the western edge of
the cutting unit. The Landslide Hazard chapter of the Mason County Critical Areas
Ordinance (available on line) requires a geo-technical assessment, consistent with section
17.01.100, for logging on or within 300 feet of slopes over 15% and a geo-technical
report for slopes of 40% or more. This FPA will require the virtually the same geo-
technical assessment or report as the site development building permit will require. I am
under the impression that such a document has already been written and will be
distributed to the Planning Department this week. (An alternative is to pull the boundaries
of the cut back to the 300-foot setback line).
Normally geo-technical documents, like stormwater site plans, are reviewed by Mason
County Public Works. However in this case the review will be contracted out to
Berryman & Henigar with their hours billed to Public Works.
I look forward to receiving the geo-technical document in the near future; hopefully your
stormwater plan will also be available to forward to Berryman &Henigar at the same
time.
Let me know how Public Works wishes to approach the Pileated Woodpecker habitat
situation. Please feel free to call me at ext. 571 or e-mail me at mms a,co.mason.wa.us
with any questions. Thank you. e
Sincerely,
. , `
Michael MacSems
FPA Planner
cc: Barbara Robinson