HomeMy WebLinkAboutGEOtechnical Assessment - BLD Engineering / Geo-tech Reports - 6/10/2004 T
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- CIVIL - STRUCTURAL - SOILS - PLANNING -
June 10, 2004
Bp
of-WA40y,
John Lang C?
P. 0. Box 2377 sS�4NA1.��
t
Belfair, WA 98528
EXPIRES��./•-C
RE: GEO-TECHNICAL RECONNAISSANCE OF LOT B, PER LEGAL ENCLOSURE & ASSESSMENT
Dear John;
The undersigned Geo-technical Engineer along with Lucas Anderson,
Geo-technician, visited the subject site on June 9th for a preliminary soil
survey and site reconnaissance. The site was investigated to determine the
stability requirements for the proper siting of a proposed residence.
We found a gently sloping lot with the bank sloping down Northerly at
9° as measured by Smart Level readings. This is typical throughout the lot.
The lot is timbered with tree cover of medium sized evergreens and an
understory of bushy plants and some small deciduous trees. Generally, the
land stability of the property is good. Photographs were taken for our file
and record.
Our test hole and soil log revealed that the underlying soil is a
glacial till; primarily of brown sandy-loam with gravel inclusions. The
upper strata of soil is forest humous.
A review of the Coastal Zone Atlas for a background on geology and
slope stability revealed no recent landslides in the near vicinity of the
lot. The parcel is located near a zone listed as stable.
Our slope stability calculations (seismic governs) yielded a factor of
safety for sliding of 1.60 versus 1.30 required.
The siting of the residence may be located anywhere on the lot with
proper front, rear and side yards. Silt fences should be installed prior
to foundation construction. The landscape buffer area may be planted in
Dutch White Clover and Creeping Red Fescue.
John Lang
Page 2
June 10, 2004
Due to the slight slope of the lot, this parcel requires a Geo=technical
Assessment.
(1) The homesite area was covered with timber which showed no distress
from any slope instability.
(2) The height of the slope across the lot is 20 feet, approximately.
(3) A Site Plan contains the location and log of the soils exploration.
(4) The soil type is a sandy-gravel mix covered with a shallow layer of
loam near the surface. The homesite is inherently stable due to
the slope and the sandy-gravel soil.
(5) Ground water was not observed on the homesite.
(6) There is about a 6 inch layer of loam at the surface; otherwise
silty-sand with gravel inclusions.
(7) The homesite is partially cleared. A foundation planting of low
shrubs is recommended at the completion of construction. Drainage
will be natural but impeeded by a seeded lawn. The construction
calls for shallow excavations and is well away from any steep slope
so it does not need a temporary erosion control plan.
(8) Potential off-site impacts are small or nill due to the minimal
changes to the landscape.
Contents of this Geo-technical Assessment:
(1) The basic soil here is a silty-sand and gravel which is noted for
its stability.
(2) See the enclosed print of lot B.
(3) The exploratory hole location is shown on the above print.
(4) Septic drain fields should be located downhill from the house
location with septic tile lines parallel with the slope.
(5) Only the homesite and the driveway need to be cleared. Areas
cleared of vegetation should be replanted by seeding or equal.
(6) A temporary erosion control plan consists of silt fences installed
during the construction of the house.
(7) An analysis of the impact of this project to on-site and off-site
locations is NIL!
r
John Lang
Page 3
June 10, 2004
Roof drains from the residence should be carried in a closed circuit
downhill to discharge into an energy dissipator or infiltration pit away
from the foundations. No ground water was observed.
A driveway from State Highway 106 will be constructed by the owner.
-tv /o'/S 15 C.
The Coastal Zone Atlas for Washington (Mason County) shows the parcel
in an Intermediate Zone for stability.
There are no on-site or off-site impacts from the proposed construction.
In my professional opinion, the proposed siting, described, herein,
should provide a stable site for the proposed residence.
Yours truly,
Rolla B. Boughan, E.
Geo-technical Engi eer
ENCLS- Legal Description & Plat
Section A-A
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CONSOLIDATED ENGINEERING SHEET NO. OF
P.O. Box 2321
BREMERTON, WASHINGINGTON 98310 CALCULATED BY 1�- DATE T"
(360) 479-5598
CHECKED BY DATE
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