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PRELIlVIINARY GEOLOGICAL ASSESSMENT
DISCOVERY BAY DEVELOPMENT '
DISCOVERY BAY VILLAGE
JEFFERSON COUNTY, WA$HII~TGTON
Prepared for:
MR. STEVE FAGER
AQUACULTURE SYSTEMS, INC.
P.O. Box 417
SEQun~I, WA 98382
Prepared by:
ALKAI CONSULTANTS, LLC
9465 PROVOST ROAD NW, STE. 204B
SILVERDALE, WA 98383
Project No. ACL04-G102
September 13, 2004
ALKA~ coNs
. U LTANTS, LLC.
Environmental Engineering • Geotechnical Engineering • Wetland Consulting
September 10, 2004 Project No. ACL04-G 102
Mr. Steve 1~ager
Aquaculture Systems, Inc.
P. O. Box 417
Sequim, WA 98382
Preliminary Geological Assessment of Slope Stability
Proposed Residential Development
Discovery Bay Village
Jefferson County, Washington
Presented herein aze the results of a preliminary geological assessment to evaluate potential erosion and landslide
hazards at the referenced site in accordance with the requirements of the Jefferson County Unified Development
Code, sections 3.6.4 "Environmentally Sensitive Areas District", 3.6.7 "Geologically Hazardous Areas", and 3.6.10
"Special Reports." The scope of the study was. developed during a site meeting on September 1, 2004 of this year,
and outlined in my letter of proposal to you dated September 2, 2004. Fieldwork for the study was undertaken on
September 1, 2004.
Site Conditions and Proposed Development
The subject pazcel is located to the west of State Highway 141 in Section 13 Township 29N Range 2W as shown on
the Vicinity Map portion of Figure 1 of this report. At the time of the site visit Lots 33, 34, and 35 were the focus of
this preliminary assessment. These lots are shown on Figure 2. It is~our understanding that initial grading on the
three lots began approximately 2 yeazs .ago with final grading completed approximately 6 months ago. The three
graded lots are located on a roughly west-east trending ridge with descending slopes towazd the south-southeast. A
primitive dirt road off of Holland Drive provides access to the lots. The graded areas of the lots had been cleared with
forested areas uphill of the lots and a small stand of fir trees on the bottom of lot 33. Amore detailed description for
each lot is as follows:
Lot 33
The native slope on the western (upper) portion of Lot 33 had been graded to an approximately 15 foot high slope
with an approximately 1.SH:1.OV ratio. The fill slope on the eastern (lower) portion of the lot is approximately 12
feet in height with steep slopes terminating near Holland Drive. It is our understanding that the proposed residential
structure for the lot will be a 2-story wood frame structure with a daylight basement.
GEOLOGIC AND GEOTECHNICAL CONSULTING
Project No_ ACL04-G102
Preliminary Geological Assessment Report Discovery Bay
September 10, 2004'
•' Page No. 2
Lot 34
A proposed building pad area for lot 34 had been developed on the top of a small ridge which is the dominant feature
of the lot. The majority of the proposed building pad area was exposed dense native soils with one area of the lot
having a fill slope (eastern portion) with a relatively steep slope. It is our understanding that the proposed residential
structure for the lot will be a 2-story wood frame structure.
Lot 35
The topography of lot 35 is a descending slope which terminates at Holland Drive. The natural slope is at a roughly
2H:1V ratio. A cut-fill pad had been developed near the top of the lot with the fill slope up to 7.0 feet in height and.
graded to a 1.SH:1.OV ratio. It is our understanding that the proposed residential structure for this lot will be a 1-story
wood frame structure.
Methodology
Soil and slope conditions of the subject property were visually. examined and evaluated using available soil exposures
and road cuts in the site vicinity and reviewing soil logs. for water wells in the general site vicinity. The local soil
stratigraphy is well exposed in the general site vicinity and dense to very dense soils are present at a shallow depth.
The use of slope cuts and slope exposures in combination with the water well soil logs provided an improved view of
the near surface site soils for evaluation.
This on site information combined with various soil exposures around the site provided a basis for a general
understanding of the local soil and geologic conditions as discussed below. Actual subsoil conditions and thickness
may vary between observation locations or as exposed in excavations or slope exposures.
In addition to the observation of available soil exposures and reconnaissance of the area, the readily available
resources listed below were reviewed.
Resources. used:
1. "Washington State Coastal Zone Atlas", Washington State Department of Ecology, Jefferson County
Volume 11.
2. Stability Map of Northeastern Jefferson County, Washington", Washington Division of Natural
Resources, Division of Geology and Earth Resources, 1976.
3: "Soil Survey of Jefferson County Washington", United States Department of Agriculture, 1960.
4. U.S.G.S. 7.5 minute series topographic map.
9465 Provost Road NW, Suite 204 6 • Silverdale, Washington 98383 • (360) 613-2407 • Fax: (360) 613-2408
Project No. ACLA4-G102
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September l0, 2004
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5. The Washington Division of Geology and Earth Resource (WDGER), "Geologic Map of Washington -
Northwest Quadrant" map.
6. The "Jefferson County Washington Resource Inventory Area 17 Generalized Su~cial Geology and
Relative Hydraulic Continuity Potential" map.
The base map for Figure 2, Site Plan was provided by the client and was prepazed by Roats Engineering (dated 1981).
Regional Geologic Setting
Site soils, topography and geology result from the advance and retreat of the Vashon Stade of the Frazier Continental
Glaciation. During the last glaciation, the continental glacier advanced across the region with various mixtures of silt;
sand and gravel being deposited ahead of and below the advancing ice sheet. These materials were in turn overridden
by the advancing ice and compacted to the present dense to very dense condition by several hundreds of feet of
moving ice. The unsorted portion of this highly compacted material became what is commonly referred to as glacial
till, a material of mixed gradation, which has the general appearance of lean concrete. Materials below the till layer
are generally identified as Advance Outwash or other pre-glacial deposits. Zones of dense to very dense, somewhat
cleaner materials, materials showing some degree of sorting or bedding, or materials of a mixed or indefinite origin
incorporated into the till unit or neaz the contact between the till and underlying pre-glacial deposits are commonly
referred to as ice contact deposits or glacial drift.
The Washington Division of Geology and Earth Resource (WDGER), "Geologic Map of Washington -Northwest
Quadrant" map, dated 2002, indicates that the site is near the contact of glacial till (Qgt) and undifferentiated outwash
(Qgo). GIacial Tiil consists of an unsorted, unstrat~ed, highly compacted mixture of clay, .silt, .sand, gravel and
boulders deposited by glacial ice. Undifferentiated outwash is composed of stratified sand, gravel, and cobbles with
occasional silt and clay-and originates in glacial outwash. The term `undifferentiated" indicates that the unit may
consist of both advance and recessional outwash but the mapping unit does not distinguish between them.
The "Jefferson County Washington Resource Inventory Area 17 Generalized. Surficial Geology and Relative
Hydraulic Continuity Potential"_ map indicates the site is neaz the contact of basil till and coarser unconsolidated
sediments (e.g. outwash, alluvium). This description appears to be consistent with the WDGER map (see Figure 3).
Over time, through weathering, root disturbance and the deposition of organics, a layer of topsoil several inches to a
foot or more in thiclrness may develop.
9465 Provost. Road NW, Suite 204 B • Silverdale, Washington 98383 • (360) 613-2407 • Fax: (360) 613-2408
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Site Soil Conditions
The United States Department of Agriculture, Soil Conservation Service, Soil Survey of Jefferson County, 1975
(SCS) indicates that the site is located in areas mapped as Clallam gravelly sandy loam (CmD) and Hoypus gravelly
loamy sand (HuD}, both with 15 to 30 percent slopes. The Clallam (CmD) deposits formed in glacial till and have a
dense cemented layer with very slow permeability at 20 to 40 inches in depth. Runoff is medium and the hazard of
water erosion is moderate. Perched water may be encountered above the cemented layer during the rainy season. The
Hoypus (HuD) deposits formed in glacial outwash. Runoff is medium and the erosion hazazd is moderate.
Based on the. observed soils, it is our opinion that the site soils are generally consistent with those indicated on the
geologic and soil maps of the azea. Differences between the mapped and observed soil conditions aze generally minor
and not unexpected, and appeaz primarily as a result of outcrop availability and mapping scale.
Surface Conditions
Present slope grades and surface conditions were examined across the property and adjacent properties. No evidence
of land sliding or slope soil movement was observed.
The "Coastal Zone Atlas of Washington", Volume 11, Jefferson County, Washington Department of Ecology, 1979
identifies slopes in the site vicinity as intermediate and unstable (IJ). Intermediate slopes are described as generally
steeper than 15 percent slopes, but can include areas of more gentle slopes where weak material or groundwater
conditions reduce stability. It should be noted that the mapping was performed in the late 1970's and does not reflect
more recent landslide activity (see Figure 4}.
The "Stability Map of Northeastern Jefferson County, Washington" map by Washington Department of Natural
Resources, Division of Geology and Earth Resources, 1976 indicates the site is neaz the contacts of class 2 and 3.
Class 2 slopes are steep slopes believed to be stable. Class 3 slopes are considered to be areas of poor natural stability
(see Figure 5).
Based on ourobservations on and azound the site azea it is our opinion that the slope area is generally stable and has
not been subjected to lazge-scale slope soil movement or landsliding.
Fieldwork for this geotechnical study was undertaken during a dryer than normal summer, and na obvious indications
of ground water flows, springs or seeps were observed back of the top of the slope or from the slope face. Withregazd
to seasonal variations in the ground water levels based on vegetation types, it appears that the site is generally well
9465 Provost Road NW, Suite 204 B • Silverdale, Washington 98383 • (360) 613-2407 • Fax: (360) 613-2408
Project No. ACL04-G102
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September 10, 2004
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drained but it is possible that perched water may periodically develop in the sandier layers within the till or along the
contact between the near surface soils and the glacial till.
CONCLUSIONS
General Comments
Based on our site observations and review of pertinent materials, it. is our opinion that the site does not meet the
requirements of the Jefferson County Unified Development Code Section 3.6.7 for classification as a geologically
hazardous area. Specifically, section 3.6.7.2 I (Erosion Hazard Areas), ii (Landslide Hazard Areas) and. iii (Seismic
Hazazd Areas). However., as previously indicated, grading which has been performed on the site has resulted in the
creation of fill slopes which will need to be regraded or require the construction of retaining wall structures. It is
Alkai's opinion that the grading on lots 33, 34 and 35 does not pose a significant threat to the overall stability of the
subject lots or adjacent lots and associated slopes. The proposed residential structures locations and associated site
development will have no effect the slope stability or existing slope conditions across the site or on adjacent
properties. .
To varying degrees maintenance of slope vegetative can aid in slowing the overall rate of any potential slope
degradation. The Washington State Department of Ecology (DOE) has three publications, which may be helpful in
developing long-term slope vegetation maintenanceJprotection and landscape plans.
1. "Slope Stabilization and Erosion Control Using Vegetation: A Manual of Practice for Coastal
Property Owners", May 1993, Publication 93-30.
2. "Vegetation Management: A Guide for Puget Sound Bluff Property Owners", May 1993, Publication
93-31.
3. "Surface Water and ground Water on Coastal Bluffs: A Guide for Puget Sound Property. Owners",
June 1995, Publication 95-107.
The site soils are moderately erodible in the disturbed state or under conditions of channelized water flow. During and
after construction runoff from the building site and yard area should be controlled and not directed to or allowed to
free-flow toward, across or over the slope area. It is recommended that through site grading, surface storm runoff
should be directed away from the slopes and collected where possible for disposal. Similarly runoff from the
buildings and surfaced azeas should be intercepted, collected, and tightlined away from all slope areas for disposal
where down slope soils, slopes, and structures are not placed in jeopardy. On no portion of the site should drywells be
used for the disposal of any collected storm water. From a geotechnical view tight lining of collected water to the tce
of the slope would be an acceptable means of disposal.
9465 Provost Road NW, Suite 204 B • Silverdale, Washington 98383 • (360) 613-2407 • Fax: (360) 613-2408
Project No. ACI.04-G102
t Preliminary Geological Assessment Report-Discovery Bay
September 10, 2004
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As to expectations for future slope behavior, it should be expected and anticipated that over time some minor
degradation of the present slopes will occur, particularly in areas of steeper slope. ff conditions remain unchanged it
can be reasonably anticipated that any future soil movement will be limited to primarily minor erosion.
Stability and Erosion Concerns
Based upon our site observations and review of pertinent materials, it is our opinion that the potential for large scale
sliding on the slopes, resulting solely from the proposed residential construction, is low.
From our current level of study it appears that without significant modification to the slopes, both the short and long
termed stability of the slopes will be primarily controlled by ground saturation. Ground saturation will result primarily
from storm rainfall and ground water migration through the site and adjacent properties. Erosion of the exposed soils
will be most noticeable during periods of rainfall and may be controlled by the use of normal erosion control
measures, i.e., silt fences, hay bales, mulching, control ditches or diversion trenching, and contour furrowing. Storm
water management is discussed in a following section.
Seismic Concerns
Although the property is located in seismic zone 3 as defined by the Uniform Building Code (UBC), as is the entire
Puget Sound region, it reportedly received no observable damage resulting from the magnitude 6.8 earthquake of
February 28, 2001. The site soils appear well drained and not of the sort normally associated with liquefaction or loss
of soil strength. But, in the event of an earthquake of adequate magnitude and/or duration some soil movement on the
steeper slopes is possible if other conditions are right. However, the potential for soil movement on this property is no
greater than that for properties elsewhere with similar slope and soil conditions. The conclusions and
recommendations contained in this report were developed cdnsidering the potential for slope faihire. Also, it is
expected that all work and designs will be completed in accordance with current UBC seismic zone 3 requirements, or
potentially more stringent future requirements.
Reference to the USGS seismic mapping indicates a PGA (peak ground acceleration} of 0.29g for the 10 percent
probability of exceedance in 50 years (475 year return period event).
RECOMMENDATIONS
As previously noted it is our opinion that the property does not meet the ordinance requirements for identification as a
geologically hazardous area. However, due to the presence of steeply sloping fill slopes we are providing the
following additional development and construction recommendations to aid in the satisfactory completion of the
9465 Provost Road NW, Suite 204 8 • Silverdale, Washington 98383 • (360) 613-2407 • Fax: (360) 613-2408
Project No. ACIA4-G10Z
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September 10, 2004
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project. The following site preparation and foundation design recommendations should be incorporated into future
site planning, design and constriction. It is recommended that a representative of Alkai Consultants review proposed
grading plans and retaining wall design.
Site Preparation and Grading
Pavement, fill or building azeas should be stripped of all sod, organic soil, existing fill and debris. In most areas, a
stripping depth of about one-foot should be anticipated. Deeper excavations maybe required to remove buried tree
root balls, stumps, or pockets of unsuitable soils or fill. Stripped soils, contaminated with organics or debris, should
be wasted off site or used in landscape areas.
Although little if any filling for site development is anticipated the following recommendations should be followed
for all fill placement. Following stripping of the site, and prior to the placement of any fill, the exposed subgrade
should be proof rolled and compacted to a fin,n, unyielding condition using equipment of appropriate size and type.
Compaction of the stripped subgrade should be continued until field density tests show that a minimum compaction of
95% of the maximum dry density, as determined by ASTM method U 1557, has been achieved in all fill, building,
roadway, and parking areas. Any soft or weaving areas .disclosed during proof rolling should be excavated and
replaced with compacted structural fill. Areas, which are to be filled to bring the building or pavement grades up td
the desired elevation, should be filled with compacted granulaz material free from roots, trash or other deleterious
materials. It is our opinion that the native till or mixed soils will be only mazginally suitable for use as wet weather
fill due to their inherent moisture sensitivity. The till soils and those having a high fines content are sufficiently fine
grained, such that with the addition of small quantities of water they become overly saturated and are difficult or
impassible to compact to the desired density. As a result, we recommend that all site grading and prepazation be
undertaken and completed during. dry weather. If grading in building or pavement areas is necessary during wet
weather and time does not permit allowing the soils to drain, we recommend that all excavated soil be removed from
the site and that materials used as structural fill (fill placed on~ slopes or under buildings or pavements) consist of free
draining gravelly sand having a maximum size of 1-1/2 inches. and with not more than 5.0% fines, material passing a
U.S. No. 200 sieve. All imported fill material should conform to the above. recommendation regazdless of the weather.
It is reconunended that permanent cut slopes not exceed 2H:1 V (50%). Fill slopes should not be steeper than 2H:1 V
(50%) for fill placed in accordance with the requirements of appendix chapter 33 of the Uniform Building Code (1997
edition) or 3 to 4H:1V (33% to 25°k) for uncontrolled fills of moderate quality material. In areas where steeper slopes
are required, retaining structures should be provided.: In areas where fills are to be made on slopes steeper than
5H:1 V the subgrade should be benched and prepared in accordance with UBC (1997) requirements prior to fill
9465 Provost Road NW, Suite 204 6 • Silverdale, Washington 98383 • (360) 613-2407 • Fax: (360).613-2408
Project No. ACIA4-G102
Preliminary Geological Assessment Report-Discovery Bay
_ September 10, 2004
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placement. Benches should be cut at a maximum vertical height of 18 inches. It should be anticipated that, if steeply
cut, the near surface soils may be subject to caving, and sloughing will occur as the soils aze exposed to drying. All
temporary cuts and excavations should be sloped or shored in accordance with local, state and federal requirements.
Additionally, slope grades (both cut and fill) in driveway traffic areas should comply with appropriate county and
local regulations.
All structural fill (fill below buildings, roadways or parking areas, or fill placed on slopes) should be placed on a firm,
properly prepared subgrade. Fill materials should be placed in layers approximately 8 inches in thickness, conditioned
to a moisture content suitable for compaction, and compacted to 95% of the maximum dry density as determined by
ASTM D-1557.
Retaining Structures
As previous discussed the existing fill slopes created from grading activities.willaeed to be regraded and/or have
retaining structures at the toe of the slopes such as cast in place concrete walls, ecology block walls or Reinforced
earth walls utilizing grid systems such as tensaz. The final decision on the retaining structure design will be
dependent on fmal slope heights.
Surface and Ground Water
Only minor storm water related problems are anticipated if site grading and preparation are undertaken during the
normally drier portions of the year. If the site work is undertaken during wet weather the contractor should be fully
prepared to deal with soil and water problems normally encountered in these materials during wet weather work
including the filtering of runoff, as needed to prevent the siltation of down slope areas. To aid in minimizing potential
erosion it is recommended that the building site not be stripped and left unvegetated or without erosion protection for
an extended period of. time prior to the actual start of construction and/or landscaping. Silt fencing and other erosion
control devices and measures may be required to control water runoff and sediment transport off the site.
Ground water related problems are not anticipated on the presently proposed building site. However, it should be
anticipated that perched water flows may develop in some areas. In that we are unable to predict where or when this
might occur we recommend that any development of incidental seeps be treated as a construction or maintenance
problem.
To preclude the possible build-up of ground water or storm runoff in the soils adjacent to the structure, it is
recommended that afour--inch diameter, perforated, rigid pipe be placed, perforations down, around the outside of the
9465 Provost Road NW, Suite 204 B • Silverdale, Washington 98383 • (360) 613-2407 • Fax: (360) 613-2408
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September 10, 2004
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building foundation at the footing subgrade elevation. All of the drainage system should be bedded in a drainage sand
.and gravel and designed to carry any accumulated water away from the structure to an appropriate discharge azea.
Roof drainage should not be connected to the footing drains but may use the same outfall piping if connected well
away from the building such that roof water will not backup into the footing drains.
The free flow of water toward or over the slopes is to be avoided due to potential erosion concerns. Landscaping.
should not be designed to direct runoff into these areas. Additionally, all runoff from roofs, driveways, patios and
hard surfaced areas should be intercepted, collected and disposed of away from structures and site slopes, and
discharged where the water will not effect down slope structures, walls, or properties. From a geotechnical
perspective, tight lining of the collected runoff to the area below the slope would be an acceptable means of disposal.
However, such a disposal system should comply with all applicable regulations and the pipe should dischazge into a
manifold-type structure'or onto an energy dissipater such as a pad of crushed: rock to aid in minimizing erosion. if an
energy dissipation pad is used it should be a minimum of three feet on a side, one foot thick, and comprised of two to
four inch crushed, rock inside a staked frame to prevent down slope migration of the rocks. It is suggested that
cleanouts be provided at convenient locations along the length of the storm drainage system for maintenance. All
piping for the drainage. system should be ridged and smooth walled. Corrugated, ADS-type piping should not be used.
Alternatively, if infiltration of the storm water is required, the infiltration system should be constructed as faz away
from the bluff as possible, preferably at the west end of the lot. However, specific recommendations for and design of
a storm water disposal system are beyond the scope of our services and should be prepared by other consultants fully
familiar with Jefferson County design and discharge requirements.
Foundation Design
We recommend that all foundations be designed to bear on the medium dense to very dense native soils or structural
fill placed and compacted as previously described. Continuous footings should nat be less than 14 inches wide and
isolated footings should not be less than 18 inches in their smallest dimension, regardless of the resulting bearing
pressure. Additional foundation sizing and design considerations should be in accordance with Uniform Building
Code requirements, as modified by local codes and regulations, in effect at the time of construction for structures
within seismic zone 3 as defined by the Uniform Building Code.
All footings on gentle slopes (<15%) should bottom a minimum of 18 inches below the lowest adjacent exterior grade
and 12 inches below the lowest interior grade. Footings on slopes steeper than 15°~ should be designed to bear a
minimum of three feet below-the finished exterior surface soil grade and be at least six feet horizontally back of the
finished soil face of the slope. It is recommended that all foundation excavations be inspected prior to placing
9465 Provost Road NW, Suite 204 B • Silverdale, Washington 98383 • (360) 613-2407 • Fax: (360) 613-2408
Project No. ACIA4.G102
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September 10, 2004
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concrete, to verify that the bearing surface has been properly cleaned, prepared and soil conditions are as anticipated.
All foundation subgrade areas should be recompacted following excavation. Bearing surfaces should be firm and free
of sloughed orwater-softened soil. Standing water should not be allowed to accumulate in the foundation excavations
For spread footing foundations designed and constructed as outlined above, an allowable soil bearing pressure of
2,000 PSF may be used for foundations bearing on the medium dense insitu soils or properly placed and compacted
structural fill. For foundations bearing on the dense to very dense insitu soils an allowable soil bearing pressure of
4,000 PSF may be used.
We estimate that total settlement for foundations designed and constructed as outlined above will be an inch or less,
with differential settlement between similarly loaded foundations potentially approaching the total settlement. It is
anticipated that most settlements will occur as the foundations are loaded. Failure.to properly place structural fill or
prepare the subgrade areas may increase settlement resulting from loading and/or shaking resulting from an
earthquake..
Slabs-on-Grade
Slab-on-grade floors may be supported on properly placed and compacted structural fill or on the medium dense to
very dense insitu native soils following preparation as outlined above. A capillary break/drainage layer consisting of
six inches of pea gravel, or clean crushed rock should be placed below the floor slab. The capillary break material
should contain less than 1.0% material passing a U.S. No. 200 sieve and less than 4.0% materialpassing a U.S. No. 10
sieve. A visqueen vapor barrier having a minimum thickness of 6-mils should be placed between the capillary break '
and the floor slab. We understand that a sand cushion between the vapor barrier and the base of the slab may improve
the curing of the slab concrete. If a sand cushion is placed between the capillary break material or the vapor barrier
and the slab, it should not contain free moisture when the slab is constructed. Excess moisture in the cushion -could
cause impervious floor coverings to bubble.
Construction Considerations _
As a preliminary guideline for temporary cuts less than 10 feet in height, we recommend temporary slopes be made no
steeper than 1H:1V for the dense to very dense glacial till and no steeper than 2H:1V in medium dense soils or
structural fill placed and compacted as outlined above. For temporary cut slopes in loose materials or over 10•leet in
height we recommend temporary slopes no steeper than 2H:1 V for the full height of the cut. Temporary slopes or
excavations should be benched as required by safety regulations in effect at the time of construction. These temporary
slope recommendations are for native soils and fill materials; flatter slopes may be required in wet weather or if soil
conditions other than those previously described are encountered. The contractor should be aware that slope height,
9465 Provost Road NW, Suite 204 6 • Silverdale, Washington 98383 • (360j 613-2407 • Fax: (360) 613-2408._
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slope inclination, and excavation depths (including utility trench excavations) should in no case exceed those
specified in local, state, or federal safety regulations; e.g., OSHA Health and Safety Standards for Excavations, 29
CFR Part 1926, or successor regulations. Such regulations are strictly enforced and, if not followed, the owner, the
contractor, or the earthwork or utility subcontractors could be liable for substantial penalties. The contractor should
be made responsible for the stability of all excavations and slopes during construction because he is continually on
site and can observe the stability of the exposed soils. In .addition, the contractor should be prepared to shore any '
unstable slope area and provide shoring as required by local, state, or federal laws or codes. '
In a disturbed condition the site soils ,may be easily eroded by channelized water or sheet flow storm runoff.
Therefore, it is recommended that all site preparation and excavation work be completed during the normally drier
portion of the yeaz. During periods of heavy rainfall, ditching should be used to divert water away from stripped areas
and visqueen should be used to cover the slopes and soil stockpiles to aid in preventing excessive surface erosion.
This covering also aids in preventing infiltration of water into the unprotected soils. All disturbed soil areas and
slopes should be replanted with fast-growing, deep-rooted grass, shrubs and other ground cover as soon after final
grading as possible. ff the vegetation is not fully established prior to the on set of wet weather, the slopes should be
covered with visqueen to aid in preventing excessive erosion and water infiltration.
REPORT LIlVIITATIONS
This preliminary report has been prepared for the exclusive use of Aquaculture Systems, Inca and their agents for use
in planning of the referenced development. The conclusions and recommendations in this report are based on our
interpretation of site conditions, as they presently exist, anticipated future construction activities, and the expectation
that the exploratory efforts adequately define the subsurface conditions across the site. The soil conditions described
in this report and the conclusions and recommendations contained in this report are provided for this specific site only
and should not be expanded for use on adjacent properties without additional exploration .and review of those sites by
our firm. The data and. report should be provided to prospective contractors for their biddingor estimating purposes,
but the report conclusions and interpretations should not be construed as a warranty of the subsurface conditions.
There are possible variations in subsurface conditions. In the event that the scope. or location of the project should
change or subsurface conditions different from those encountered during this study be observed or suspected, we
should be advised. At that time a review of the changed conditions will be made, and alternative or remedial
recommendations given as required.
NOTE: We have not explored subsurface conditions as part of this study, nor have we evaluated the site for the
potential presence of contaminated soil, and have not evaluated or addressed ground water conditions or concerns
9465 Provost Road NW, Suite 204 B • Silverdale, Washington 98383 • (360) 613-2407 • Fax: (360) 613-2408
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September 10, 2004
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except as noted in this report. The evaluation of possible environmental or geo-environmental considerations is
beyond the scope of this report.
The owner and the contractor should make themselves aware of and become familiaz with applicable local, state, and
federal safety regulations, including current OSHA excavation and trench safety standards. Construction site safety
generally is the sole responsibility of the contractor. The contractor shall also be solely responsible for the means,
method, techniques, sequences, and operations of construction operations. The firm, Alkai Consultants, LLC is
providing the preceding information and recommendations solely as a service to Discovery Bay Village Water
Company. Under no circumstances should the provision of this information or recommendations beconstrued to mean
that the firm Alkai Consultants, LLC (or subcontractors) are assuming responsibility for construction site safety or
the contractor's activities; such responsibility is not.implied and should not be inferred.
Within the limitations of scope, schedule, and budget for this work, it is warranted that the work has been done in
accordance with generally accepted practices followed in this area at the time this is report was made. No other
warranty, expressed or implied is made.
Should you have~any questions or concerns, which have not been addressed, or if we may be of additional assistance,
please call our office at (360) 613-2407.
sincerely,
Shawn E. Williams L.E.G., R.E.A.
Senior Licensed Engineering Geologist
9465 Provost Road NW, Suite 204 B • Silverdale, Washington 98383 • (360) 613-2407 • Fax: (360) 613-2408
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from T
/~ L K A ~ CONSULTANTS, LLC.
Environmental Engineering • Geotechniwl Engineering • Wetland Consulting
FIGURE 1 VICINITY MAP
Project Name: Discovery Bay Developmen N
Location: Jefferson County, Washington
Project: ACL-G102
Client: Mr. Steve Fager
Date: 9/10/04
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I-IWY 101
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Legend
Bedrock
Coarser Unconsolidated Sediments (e.g. outwash,
alluvium)
Finer Unconsolidated Sediments (e.g. lacustrine,
undifferentiated glacial deposits, ablation till.)
Basil till
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Note: Map adapted from Jefferson County Washington Resource Inventory Area 17 Generalized Su~cial Geology and
Relative Hydraulic Continuity Potential Map.
FIGURE 3: Surficial Geoloay
Project Name: Discovery Bay Developmen
A LK A I CONSULTANTS, LLC. Location: Jefferson County, Washington
Project: ACL-G102
Environmental Engineering • Geotechnical Engineering • Wetland Consulting Cherlt' Mr. Steve. Falter.
Date:.9/10/04
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Note: Ma ada ted from De t. of Ecolo Coastal Zone Atlas of
A LK A I CONSULTANTS, LLC.
Environmental Engineering • Geotechnical Engineering • Wetland Consuking
~ington, Volume 11, 1979 (Jefferson County)
FIGURE 4 Coastal Zone Atlas
Project Name: Discovery Bay Developme
Location: Jefferson County, Washington N
Project: ACL-G102
Client: Mr. Steve Fager
Date: 9/10!04
Note:
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from "Stability Map of Northeastern
A LK A I CONSULTANTS, LLC.
Environmental Engineering • Geotechnical Engineering • Wetland Consulting
nty, Washington", 1976, Washington D.N.R.
FIGURE 5 Jefferson County Slope Stability
Project Name: Discovery Bay Developmen N
Location: Jefferson County, Washington
Project: ACL-G102
Client: Mr. Steve Fager
Date: 9/10104
Legend
^ .Class 2: Steep slopes believed to be stable.
^ Class 3: Areas of poor natural stability
ALKAI Consultants, LLC.
9465 Provost Road NW Suite 204 6
Silverdale, WA 98383
Phone (360) 613-2407
Fax (360) 613-240$
Environmental • Geotechnical En~ineerin~ • Wetlands Consulting