HomeMy WebLinkAbout980100309 Geotech AssessmentPrepared For Jim Fannin
August 15, 2003
For the Property Described as
Tax # 980100309
Section 21, Township 25 North, Range 2 East, W.M.
Jefferson Coonty, Washington
Prepared by
NORTHWESTERN TERRITORIES, INC.
717 S. Peabody Street
Port Angeles, Washington 98362
Phone 360-452-8491 Fax 360-452-8498
Web Site www.nti4u.com
E-mail info@nti4u.com
GEOTECHNICAL REPORT
,' NORTHWESTERN TERRITORIES, INC.
A JLS GROUP COMPANY
71T SOUTH PEABODY STREET, PORT ANGELES, WA 88362
Engineers Land Surveyors Geologists
~~, Construction Inspection Materials Testing
(360) 452-8491 FAX 452-8498 www.ntl4u.COm E-Mall: Info@ntl4u.com
JLS GROUP,
ANC. ~ Geotechnical Report
Tax # 980100309
August 15, 2003
Jim Fannin
706 South 56th Ave.
Yakima, WA 98908
Subject: Geotechnical report for Tax # 980100309 located in Section 21, Township 25
North, Range 2 East, W.M., Jefferson County, WA
Dear Mr. Fannin:
Background
At your request, Bill Payton, Engineering Geologist with Northwestern Territories Inc. conducted
a bluff stability inspection at the above-mentioned property on June 2, 2003. The purpose of this
inspection was to examine the marine bluff at the subject site by visual means in order to
determine'the relative stability of the bluff and make recommendations in regards to the
proposed construction of a single family residence.
Site Description .
The subject high bank waterfront property is located on Canal Lane off of Highway 101 south of
Brinnon. The property overlooks Hood Canal to the east and is bounded on the north-and south
by residential property (Figure 1). Existing homes adjacent to the subject p"roperty on the north
and south are within 14.5'.to 15.5' of the top of the bluff. .
The underlying material at the subject property is unique for this-area in that it appears fo be_
predominantly basalt bedrock as opposed to soil The property is situated on a lobe thatjuts into
Hood Canal.-The Washington State Department of Ecology's Coastal Zohe Atlas maps this lobe
as basalt (Figure 2 and 3 and Photo 1).-The basalt is exposed~on the bluffand also was
encountered in some of the test pits that.were-excavated in conjunction with the septic system
design: It also appears that that there is a shallow covering of glacial till or weathered basalt .
over the basalt bedrock.
The upland portion of the property is mostly cleared and vegetated with grass and weeds, with
patches of young to mature trees (Photo 2). The upland. is roughly flat and
slopes gently towards the bluff at about 5 degrees. Test pits had been excavated in a few
locations in conjunction with the septic system design. The soil exposed in one. test
pit close to the bluff appeared to be glacial till or weathered basalt composed of silty sand and
gravel with cobbles down to the bottom of the test pit at about 4.5'.
The bluff at the property is about 41 feet high. The lower bluff is nearly vertical and composed of
basalt rock. The upper bluff has slopes ranging from about 23 degrees to 36 degrees and is well
indicating that minor downslope creep of the surface soils is occurring. One tree at the top of the
vegetated with young to mature trees and brush. Some of the trees have curved trunks
bluff was leaning over and probably should be removed prior to home construction. The upper
bluff soils are within or below the "angle of repose" which is defined as the maximum slope or
angle at which loose, cohesionless material remains stable. It commonly ranges between 33
and 37 degrees on natural slopes. No springs or seeps were noticed on the bluff and no
evidence of landslides was noticed. Access to the beach was gained via a stairway located at
the north end of the property. The beach is also composed of basalt with a covering of boulders
and cobbles.
Site Geology
The Washington State Department of Ecology's Coastal Zone Atlas maps the upland and bluff
area of the subject property as basalt of the Crescent Formation (Tcv). The rocks in this
formation are the oldest in this region. This basalt consists of pillow lava (formed underwater)
and flow breccia with lesser-amounts of massive diabase, tuff breccia and sedimentary rocks.
The Atlas maps-the slope stability of the bluff in the area of the property as Intermediate (I) and
the stability of the upland as Stable (S) (Figure 4).
Descriptions from the Department of Ecology's "Geology and Ground-Water Resources of
Eastern Jefferson County, Washington" were consistent with the Coastal Zone Atlas soil
descriptions.
According to the Soil Survey of Jefferson County Area, Washington (United States- Department
of Agriculture, 1.975), the subject-site is in an area mapped as the Olete-Hoodsport complex
(OpD) (See Appendix). The Olete soil formed in basalt bedrock and is underlain by basalt. at a
depth of 20 to 30 inches. Rurioff of Phis-soil is slow to medium and the hazard of water erosion is
slight to moderate. The Hoodspor-t soil formed in glacial tilt and has a very slowly permeable
cemented layer at a depth of 20 to 36 inches. Runoff of this soil is-slow to medium and the
hazard of water erosion is slight to mode. rate. A perched water table is on top of the cemented
layer during the -rainy season.
Visual observations made in the area were consistent with the above descriptions.
Conclusions and Recommendations
The bluff at the subject property appears to be grossly stable with no evidence of slide activity,
The lower bluff is composed of basalt bedrock that seems to be weathering very
slowly, and the upper bluff soils are at or below the "angle of repose" with agood-stand of
mature trees that further attests; to the stability of the bluff.
Based upon our investigation, we recommend that the landslide hazard buffer be set at 15 feet
from the top of the bluff.
The following recommendations should also be considered with regards to the proposal:
1. It will be necessary to maintain ground cover on soil areas in order to reduce erosiori
from surface runoff. Any bare areas that develop should be revegetated. Native deep-
rooted vegetation that requires little or no irrigation would be the~most beneficial.
Please consult the online publications mentioned below for further information.
2. Vegetation on the bluff face provides stabilization to the bluff face soils and helps
remove water from the soil. Existing established vegetation should be left in as natural
2
3. state as possible. If a better view is desired, minor thinning and pruning should be
done in such a way that minimizes disturbance to the soil and root zone and that
insures the continued heal#h of the vegetation. It may be worthwhile to consult a tree
expert in this matter.
4. Heavy irrigation or other activities that would contribute large quantities of water to the
soil should be avoided.
5. Surface runoff should not be allowed to flow over the face of the -bluff and cause
erosion of the bluff face soils. One way to mitigate this if necessary would be to
construct a swale or interceptor drain on the upland and direct the water to a
catchment area and then to the beach (or to the rock exposed in the lower bluff) via
tightline. Please see the online publications recommended below for more information
on this subject.
6. Surface runoff from hard surfaces such as roofs, driveways, walkways and patios
should be controlled and routed to the beach (or to the rock exposed in the lower bluff)
via tightline such that surface water discharge to adjacent properties does not
significantly exceed predevelopment conditions.
7. Silt fences orother-sediment control devices may be needed during construction such
that sedimentation to adjacent properties does not significantly exceed
predevelopment conditions.
8. Drainage control devices should be maintained in good working order and inspected at
least once a year.
9. An engineered drainage and erosion control plan should be developed for this property
to address items 4, 5, 6 and 7 above.
Based on the findings, recommendations and limitations of this report:
1. There should be minimal landslide hazard as suggested by a lack- of evidence of
landslide activity in the vicinity in the past.
2. Observations of .slope stability indicate that the proposal should not be subject to risk of
landslide. under the current conditions that exist at the site.
3. The proposal should not increase surface water discharge or sedimentation to adjacent
properties. beyond predevelopment conditions.
4. The proposal should not decrease slope stability on adjacent properties.
5. The proposal should be stable under normal geologic conditions.
For further information please review the three online publications published by the Washington
State Department of Ecology (DOE) entitled: "Slope Stabilization and Erosion Control Using
Vegetation", "Vegetation Management: A Guide for Puget Sound Bluff Property Owners" and
"Surface Water and Groundwater on Coastal Bluffs". These publications are now out of print but
can be obtained from the DOE website at: http://www.ecy.wa.gov/biblio/sea html under the 1993
and 1994 year heading. The DOE website also contains much more useful information
regarding slope stability and site development; this reference is highly recommended.
3
Limitations
This report has been prepared for your exclusive use in conjunction with the above referenced
project. The report has not been prepared for use by others or for other locations. It may be
used by others only with the expressed written permission of the Engineer.
Within the limits of scope, schedule and budget, this report was prepared in general accordance
with accepted professional engineering and geological principles and practices in this or similar
localities at the time the report was prepared. No other warranty, expressed or implied, is made
as to the conclusions and professional advice included in this report.
The observations, conclusions and recommendations presented in this report were based on
our visual observations of the subject property at the time of our site visit; no laboratory tests
were performed. Soil and geologic conditions can vary significantly between test holes and/or
surface outcrops. If there is a substantial lapse of time, conditions at the site have changed or
appear different than those described in this report, we should be contacted and retained to
evaluate the changed conditions and make modifications to our report if necessary.
Sincerely,
NORTHWESTERN TERRITORIES, INC.
,~
~~~
ti
Robert A. Leach, P.E., MBA
Principal Engineer
/~o`O~R~ ~S~~q~
hQ1 C~Z
h
'O~ ~PF. 13772 p ~,~
O,o ~/STERN ~~
~SS~~NAL ENG~
EXPIRES 12/30/2004
Bill Payton, L.E.G.
Engineering Geologist
G:\Gen\Bill\ReportslFANJ0301.b1uff stability.21(25-2}.Brinnon.doc
4
Expires 11-06-U3
APPENDIX
Photo 1. View of beach and lower bluff at subject property.
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FOR INFORMATIONAL PURPOSES ONLY-
Jefferson County does not attest to the accuracy of the data contained herein and makes no warranty with respec~
correctness or validity. Data contained in this map is limited by the method and accuracy of its collection. Thu May
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;eologic map shows the distribution of different earth
•ials within a particular area. As these materials are of-
~vered by several feet of "agricultural soil" and further
fired by vegetation, tl~e process of geologic mapping
rbles detective work. The field geologist must recon-
a three dimensional puzzle with most of the pieces
ng. To do this, tl~e geologist must examine as many nat-
~r manmade exposures of the earth materials as possible.
studying beach bluffs, stream banks, road cuts, and oth-
posures, all indirect information such as water well logs
lescriptions of similar units in other areas is used. These
are supplemented by a careful study.of atrial photo-
is. The photographs give abroad view of the landforms
:nt and this knowledge allows the geologist to come to
Tonal conclusions as to the nature and distribution of the
rent earth materials.
r integral part of any geologic map is tl~e explanation or
nd, which describes tl~e rock units mapped and shows '
age relationships. Although sometimes seen as academic
rpractical by the layman, a knowledge of the age of a unit
rseful tool in fire preparation of a geologic map. As the
ence of units is rarely complete at any given place, abso-
ages obtained from radiometric dating or fossil identifi-
~n, or relative ages obtained through interpretation of the
ionships among geologic units are useful in projecting
vn correlations into poorly understood or unknown areas.
geologic map leaves much room for interpretation and
anal judgement. For example, where a formation lenses
aterally it may thin from tens of feet in thickness to inch-
~er a distance of a mile or more. The decision of where a
's thickness has become insignificant and therefore un-
pable will vary from one geologist to another. On t}re
r hand, mapping of a vertical contact between two
kedly different formations exposed in a beach bluff may
one with great accuracy and complete agreement be-
n two mappers. Also, as the degree of exposure between
ogle materials may change from place to place, the "con-
t an-
bedrock and the Vashon drift, mostly drift deposited during
pre-Fraser glaciations; this drift is correlated with the Double
Bluff and Possession Drifts recognized on Whidbey Island. It
is also tentatively correlated with Salmon Springs Drift of the
southeastern Puget Lowland. Part of the pre-Vashon sedi-
ments were laid down by streams and lakes during interglaci-
ations and are correlated with the Whidbey and perhaps the
Kitsap Formation. The oldest Quaternary sediments are in-
tensively weathered and may be equivalent to the Logan Hill
Formation of the southern Puget Lowland. In some places
Holocene deposits cover the Tertiary bedrock and the Pleis-
tocene sediments in the form of postglacial alluvium (stream
deposits), colluvium {material moving downslope due to
gravity), lake beds (including peat), and beach deposits.
KITSAP COUNTY GEOLOGY
Seacliffs in Kitsap County exhibit drifts of two glaciations
which are separated by fine-grained sediments deposited dur-
ing the Whidbey interglacial period. Till and outwash associ-
ated with the younger Vashon Stade of the Fraser Glaciation
mantle most of the county uplands. Isolated outcrops of
Tertiary basaltic bedrock are located south of Bremerton,
and isolated Oligocene-Miocene marine sediments occur near
Restoration-Point on Bainbridge Island. _
DESCRIPTION OF GEOLOGIC UNITS
Crescent Formation (Tcv, Tct) The oldest rocks in this
region belong to a predominantly volcanic sequence called
the Crescent Formation. This name was assigned originally to
1200 feet of basalt and interbedded pyroclastic and sedimen-
tary rocks exposed on the west side of Crescent Bay in Clal-
lam County; however, they are now considered part of a
much thicker volcanic sequence, which is exposed at Cres-
cent Bay and Tatoosh Island. Identification of fossils from
sedimentary interbeds within the Crescent Formation indi-
cate an age of middle and possibly early Eocene.
nee level" in mapprng will also vary from one area o~ Tcv Crescent Formation, basalt is afine-grained member
- consisting of pillow lava and flow breccia with lesser amounts
I~ID USE APPLICATIONS
tdividuals who make land use decisions, whether they be
perty owners, developers, engineers, or administrators,
improve their judgement if provided with more and bet-
nformation. Geologic maps provide usefu[ data on the
racleristics of the underlying rocks and "engineering"
s. For example, physical properties and relationships be-
en geologic units dictate the nature of occurrence and
vement of groundwater. This groundwater-controlling as-
t of the geologic units is crucial to many land use ques-
rs, not only from the water supply point of view but from
water-as-a-nuisance point of view. Questions regarding
gel of garbage dump leachates or the existence of ground-
er perching layers that may cause landslides can only be
veered after a study of the subsurface materials.
~ geologic map can also provide information on the pres-
:e or absence of other resources such as gravel, quarry
k, or peat. Foundation characteristics during normal con-
ions and under eartlrcluake shock stress can be inferred
m a knowledge of nr;~t~rials be,re:~t.l~ the surface. Geologic
,__. _ .,,....,.,.,.,t ,-„ram ;~ rr,r sr~i,ilirv of slopes. Some
of massive diabase, tuff breccia, and sedimentary rocks.
Commonly, the volcanic rocks are dark gray aphanitic or
finely crystalline basalt which grade both laterally and verti-
cally into or interfinger with other varieties of extrusive or
_pyroclastic rocks. All of these extrusive rocks exhibit intense
fracturing by auto-brecciation and structural deformation.
Alteration products of chlorite and serpentine minerals pre-
dominate in these brecciated basalts. In some places, Eocene
or younger basaltic dikes occur.
Tct Crescent Formation, tuffaceous consists.of sedimen-
tary rocks and tuff member which form a distinct unit com-
posed of light greenish-gray, water laid tuff breccia and
tuffaceous sedimentary rocks as an interlayer in the Crescent
Formation. These rocks are more siliceous than the majority
of the Crescent Formation.
TI ~,yre conglomerate consists of Tertiary conglomerate,
including some interbedded sandstone.
Tv Volcanic rocks are basaltic lava flows, exposed along
t}re west side.of Sinclair Inlet south of Bremerton, consisting
of fine-grained, dark basalt with zones of zeolite amygdules.
rnR;v;rtnal flews are eenerally less than 30 feet thick.
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:ologic map shows the distribution of different earth
als within a particular area. As these materials are of-
vered by several feet of "agricultural soil" and further
~ed by vegetation, the process of geologic mapping
tiles detective work. The field geologist must recon-
a three dimensional puzzle with most of the pieces
g. To do this, the geologist must examine as many nat-
r manmade exposures of tilt earth materials as possible.
studying beach bluffs, stream banks, road cuts, and oth-
~osures, all indirect information such as water well logs
ascriptions of similar units in other areas is used. These
re supplemented by a careful study of atrial photo-
s. The photographs give abroad view of the landforms
it and this knowledge allows the geologist to come to
onal conclusions as to the nature and distribution of the
ent earth materials.
integral part of any geologic map is tl~e explanation or
id, which describes the rock units mapped and shows
ige relationships. Although sometimes seen as academic
practical by the layman, a knowledge of the age of a unit
~eful tool in [he preparation of a geologic map. As the
nee of units is rarely complete at any given place, abso-
ges obtained from radiometric dating or fossil identifi-
t, or relative ages obtained through interpretation of the
~nships among geologic units are useful in projecting
n correlations into poorly understood or unknown areas.
;eologic map leaves much room for interpretation and
nal judgement. For example, where a formation lenses
.terally it may thin from tens of feet in thickness to inch-
°r adistance of a mile or more. The decision of where a
thickness has become insignificant and therefore un-
~able wit[ vary from one geologist to another. On the
hand, mapping of a vertical contact between two
edly different formations exposed in a beach bluff may
one with great accuracy and complete agreement be-
t two mappers. Also, as the degree of exposure between
~gic materials may change from place [o place, the "con-
1 f ne area to an-
bedrock and the Vashon drift, mostly drift deposited during
pre-Fraser glaciations; this drift is correlated with the Double
Sluff and Possession Drifts recognized on Whidbey Island. It
is also tentatively correlated with Salmon Springs Drift of the
southeastern Puget Lowland. Part of the pre-Vashon sedi-
ments were laid down by streams and lakes during interglaci-
ations and are correlated with the Whidbey and perhaps the
Kitsap Formation. The oldest Quaternary sediments are in-
tensively weathered and may be equivalent to the Logan Hill
Formation of the southern Puget Lowland. In some places
Holocene deposits cover the Tertiary bedrock and the Pleis-
tocene sediments in the form of postglacial alluvium (stream
deposits), colluvium (material moving downslope due to
gravity), take beds (including peat), and beach deposits.
KITSAP COUNTY GEOLOGY
Seacliffs in Kitsap County exhibit drifts of two glaciations
which are separated by fine-grained sediments deposited dur-
ing the Whidbey interglacial period. Till and outwash tissoci-
ated with the younger Vashon Stade of the Fraser Glaciation
mantle most of the county uplands. Isolated outcrops of
Tertiary basaltic bedrock are located south of Bremerton,
and isolated Oligocene-Miocene marine sediments occur near
Restoration Point on Bainbridge island. _
DESCRIPTIbN OF GEOLOGIC UNITS
Crescent Formation (Tcv, Tct) The oldest rocks in this
region belong to a predominantly volcanic sequence called
the Crescent Formation. This name was assigned originally to
1200 feet of basalt and interbedded pyroclastic and sedimen-
tary rocks exposed on the west side of Crescent Bay in Clal-
lam County; however, they are now considered part of a
much thicker volcanic sequence, which is exposed at Cres-
centBay and Tatoosh Island. Identification of fossils from
sedimentary interbeds within the Crescent Formation indi-
cate an age of middle and possibly early Eocene.
Tcv Crescent Formation, basalt is afine-grained member
consisting of pillow lava and flow breccia with lesser amounts
of massive diabase, tuff breccia, and sedimentary rocks.
-Commonly, the volcanic rocks are dark gray aphanitic or
finely crystalline basalt which grade both laterally and verti-
cally into or interfinger with other varieties of extrusive or
.pyroclastic rocks. All of these extrusive rocks exhibit intense
fracturing by auto-brecciation and structural deformation.
Alteration products of chlorite and serpentine minerals pre-
dominate in these brecciated basalts. In some places, Eocene
or younger basaltic dikes occur.
Tct Crescent Formation, tuf[aceous consists.of sedimen-
tary rocks and tuff member which form a distinct unit com-
posed of light greenish-gray, water laid tuff breccia and
tuffaceous sedimentary rocks as an interlayer in the Crescent
Formation. These rocks are more siliceous than the majority
of the Crescent Formation.
TI Il.yre conglomerate consists of Tertiary conglomerate,
including some interbedded sandstone.
Tv Volcanic rocks are basaltic lava flows, exposed along
the west side of Sinclair Inlet south of Bremerton, consisting
ce level to mapping will a so vary rom o
1D USE APPLICATIONS
iividuals who make land use decisions, whether they be
erty owners, developers, engineers, or administrators,
mprove their judgement if provided with more and bet-
iformation. Geologic maps provide useful data on the
icteristics of the underlying rocks and "engineering"
For example, physical properties and relationships be-
n geologic units dictate the nature of occurrence and
°ment of groundwater. This groundwater-controlling as-
of the geologic units is crucial to many land use ques-
., not only from the water supply point of view but from
valet-as-a-nuisance point of view. Questions regarding
~1 of garbage dump leachates or the existence of ground-
r perching layers that may cause landslides can only be
~ered after a study of the subsurface materials.
geologic map can also provide information on the pres-
or absence of other resources such as gravel, quarry
or peat. Foundation characteristics during normal con-
~n~ and under eartltnuake .shock stress can be inferred
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80IL sURVEY
slow to ponded, and tlic hazard of ~vatcr erosion is slight or
nonexistent. A seasonal water table is at a depth of 0 to 12
inches.
This soil is used mainly for growing pasture and truck
crops. Capability unit II~v-2; not assigned to a woodland
group.
Olete Series
The Olete series consists of well~lrained, very gravelly
soils underlain by basalt bedrock at a depth of 20 to 30
inches. These soils arc on rough, broken uplands. Slopes
range from 0 to 90 percent. Elevation ranges from slightly
above sea level to about 1,000 feet. These soils formed in
weathered basalt under Douglas-fir, western redcedar, red
alder, madrone, rhododendron, and salai. Annual precipita-
tion is about 28 to 32 inches. The average annual air• tempera-
ture is 50°F. The above 32°F growing season ranges from
about 190 to 230 days, and the above 28°F growing season
ranges from about 200 to 260 days. These soils are associated
with Ahl, Alder~vood, Clallam, Everett, Grove, Hoodsport,
and Triton soils.
In a representative profile the upper 3 inches of the soil
is dark reddish-brotivn very gravelly silt loam. Below this,
to a depth of 18 inches, is dusky-red very gravelly silt loam.
Beneath this, and extending to a depth of 24 inches, is
weak-red very stony silt loam that is 80 percent or more
coarse basalt gravel and stones. This material is underlain
by basalt bedrock, which is, generally fractured. Rounded
pebbles and angular basalt stones are scattered throughout
these soils.
Olete soils are almost entirely wooded, but a few acres are
used for rural homesites.
Olete very gravelly silt loam, 0 to 30 percent slopes
(OeD).-This nearly level to hilly soil is in areas of upland
slopes. Most slopes range from 10 to 20 percent. i~
Representative profile 0.5 mile south of Knapp farm and
0.25 mile west of State Highway 9E; on logging road 150
yards southwest of basalt rock quarry in SWINE%SW%
sec. 19, T. 28 N., R. 1 E.:
Ol-2 inches to 1 inch, leaves, needles, and twigs.
02-1 inch to 0, decomposed leaves, needles, and twigs.
B21ir--0 to 3 inches, dark reddish-brown (2.5YR 3/4) very gravelly
silt loam, weak red (2.5YR 5/2) dry; moderate, very fine and
fine, granular structure; hard very friable, slightly sticky,
nonelastic; many fine and medium roots; 55 percent angular
pebbles; slightly acid; abrupt, wavy boundary. (2 to 6 inches
thick)
B22ir-3 to 18 inches, dusky-red (2.5YR 3/2) very gravelly silt
loam, pale red (2.5YR 6/2) dry; massive; hard, friable, slightly
sticky, nonelastic; common fine roots; 65 percent angular
pebbles; slightly acid; gradual, irreguar boundary. (10 to 16
inches thick)
C-18 to 24 inches, weak-red (2.5YR 4/2) very stony silt loam,
pale red (2.5YR 6/2) dry; massive; hard, friable, slightl
sticky, nonelastic; 8o percent coarse fragments; slightly acid;
clear, irregular boundary. (2 to 8 inches thick)
R-24 inches, basalt bedrock.
Depth to basalt bedrock ranges from 20 to 30 inches. The B
horizons range fmm dark reddish brown to dusky red. Gravel and
atones in the B horizons range from 50 to 80 percent. In the C
horizon texture is silt loam or loam. This horizon ~s 75 to 90 percent
coarse gravel and stones. Basalt stones and cobbles are in the A and
B horizons in places.
Included ~s1th this soil in mapping are small areas of
Rock outcrop and shallow soils.
This soil is well drained. Permeability is moderate. Roots
penetrate to a depth of 20 to 30 inches. This soil holds about
2 to 4 inches of water available for plants. Runoff is slow to
medium, and the hazard of water erosion is slight to moder-
ate. '
This soil is used mainly for production of trees and for
wildlife habitat and recreation areas. Capability unit VIe-1;
woodland group 3d2.
Olete verb gravelly silt loam, 30 to 50 percent slopes
(OeE).-This steep soil is on upland slopes in rough, broken
country that has basalt outcrops and escarpments present
in places.
Runoff is rapid, and the hazard of water erosion is severe.
This soil is used for production of trees and for wildlife
habitat and recreation areas. Capability unit VIe-1; wood-
land group 3d2.
Olete-Alderwood complex, 0 to 30 percent slopes
(OID).-This mapping unit is made up of about 60 percent
Olete very gravelly silt loam, 0 to 30 percent slopes, and 40
percent Aldenvood gravelly sandy loam, 0 to 15 percent
slopes. The Olete soil is rolling to hilly, and the Alderwood
soil is undulating to gently roiling.
The soils of this complex are used mostly for production of
trees and for wildlife habitat and recreation areas. Small
areas of the Alderwood soil are used as permanent and sum-
mer rural homesites and for growing pasture, hay, berries,
fruit, and vegetables. Capability unit VIe-1; woodland
group 3d2.
Olete-Clallam complex, 0 to 30 percent slopes
(OmD).-This mapping unit is made up of about 60 percent
Olete very gravelly silt loam, 0 to 30 percent slopes, and 40
percent Clallam gravelly sandy loam, 0 to 15 percent slopes.
The Olete soil is rolling to hilly, and the Clallam soil is un-
dulating to gently rolling.
The soils of this complex are used mostly for production of
trees and for wildlife habitat and recreation areas. Small
areas of the Clallam soils are used for permanent and sum-
mer rural homesites and for growing pasture, hay, vegetables,
fn~it, and berries. Capability unit VIe-1; woodland group
3d2.
Olete-Hoodsport complex, 0 to 30 percent slopes
(OpD).-This mapping unit is made up .of about equal
proportions of Olete very gravelly silt loam, 0 to 30 percent
slopes, and Hoodsport very gravelly sandy loam, 0 to 15
percent slopes. The Olete soil is rolling to hilly, and the Hoods-
port soil is undulating to gently rolling.
The soils of this complex are used mainly for production
of trees and for wildlife habitat and recreation areas. Cap-
ability unit VIe-1; woodland group 3d2.
Olete-Rock outcrop complex, 50 to 90 percent slopes
(OrF).-This mapping unit is made up of about 50 to 70
percent of an Olete very gravelly silt loam and 30 . to 50
percent basalt stones and Rock outcrop.
Runoff is very rapid, and the hazard of water erosion is
very severe. This complex is used mainly for production of
trees and for wildlife habitat and recreation areas. Capability
unit VIIs-1; woodland group 3d2.
Phelan Series
The Phelan series consists of moderately well drained,
gravelly soils that have a very slowly permeable cemented
layer at a depth of 10 to 20 inches. The soils formed in glacial
till on stream and river valley side slopes in the western
Olympic foothill areas. Slopes range from 30 to 80 percent.
Elevation ranges from about 200 to 1,000 feet. Native vegeta-