HomeMy WebLinkAboutGEO2010-00021 - GEO Geological Review - 4/26/2010 a00�/�
Mason County Department of Community Development +
Submittal Checklist For a Geotechnical Report
Instructions:
This checklist must be submitted with a Geotechnical Report and completed, signed, and stamped by the
licensed professional(s)who prepared the Geotechnical Report for review by Mason County pursuant to
the Mason County Resource Ordinance. If an item found to be not applicable, the report should explain
the basis for the conclusion.
Applicant/Owner ESt"�.�eS R�S�x10.�tDb• Parcel# 2 j 9D j—.5 D—OOD93 Lo+4D A)
Site Address N oY'� 4- v �L��Vrl Cx +0 s t+ e J
(1) (a)A discussion of general geologic conditions in the vicinity of the proposed development,
Located on page(s) S
(b) A discussion of specific soil types
Located on page(s) 3
(c) A discussion of ground water conditions
Located on page(s) ��'��
(d) A discussion of the upslope geomorphology ' " ";" }
Located on page(s) q r,
(e) A discussion of the Nation of upland waterbodies and wetlands +(_•
Located on page(s) -
(f) A discussion of history of landslide activity in the activity in the vicinity, as available in the
referenced maps and record
Located on page(s) .S
(2) A site plan which identifies the important development and geologic features.
Located on Map(s)
�'}ac,.� 3 £ "'
(3) Locations and logs of exploratory holes or probes.
Located on Map(s) Fj t A 440 4-,. I
(4) The area of the proposed development, the boundaries of the hazard, and associated buffers and
setbacks shall be delineated (top, both sides, and toej on a geologic map of the site.
Located on Map(s) 4o.cA,, 4 �� 1 4 "7
(5) A minimum of one cross section at a scale which adequately depicts the subsurface profile, and
which incorporates the details of proposed grade changes.
Located on Map(s) 7 -u��, 5
(6) A description and results of slope stability analyses performed for both static and seismic loading
conditions. Analysis should examine worst case failures. The analysis should include the
Simplified Bishop's Method of Circles. The minimum static safety factor is 1.5, the minimum
seismic safety factor is 1.1. and the quasi-static analysis coeffients should be a value of 0.15.
Located on page(s) 7, 8
(7) (a)Appropriate restrictions on placement of drainage features
Located on page(s) N/A $
(b) Appropriate restrictions on placement of septic drain fields
Located on page(s) f4/& *j
(c) Appropriate restrictions on placement of compacted fills and footings
Located on page(s)
Page 1 of 2 Form Effective June 2008
Disclaimer: Mason County does not certify the quality of the work done in this Geotechnical Report.
6' (d) Recommended buffers from the landslide hazard areas shoreline bluffs and the tops of other
slopes on the property.
Located on page(s) N�At
(e) Recommended setbacks from the landslide hazard areas shoreline bluffs and the tops of
other slopes on the propNrty� � ��a\ ✓�` ��15 I � `Za�,T,��.
Located on page(s)
ns for the preparation of a detailed clearing and grading plan which specifically
(8) Recommendations p p 9
identifies vegetation to be removed, a schedule for vegetation removal and replanting, and the
method of vegetation removal.
Located on page(s)
(9) Recommendations for the preparation of a detailed temporary erosion control plan which
identifies the specific mitigating measures to be implemented during construction to protect the
slope from erosion, landslides and harmful construction methods.
Located on page(s) iU
(10) An analysis of both on-site and off-site impacts of the proposed development.
Located on page(s) 10
(11) Specifications of final development conditions such as, vegetative management, drainage,
erosion control, and buffer widths.
Located on page(s) 10..
(12) Recommendations for the preparation of structural mitigation or details of other proposed
mitigation. ' I
Located on page(s)
(13) A site map drawn to scale showing the property boundaries, scale, north arrow, and the location
and nature of existing an propose development on the site.
Located on Map(s)
I e_ y'Z.�� w !"�� hereby certify under penalty of
specialized knowledge of
perjury that I am a civil engineer licensed in the to of Washington with g
geotechnical/geological engineering or a geologist or engineering geologist licensed in the State of
Washington with special knowledge of the local conditions. I also certify that the Geotechnical
Report, dated Ap)r Z,�.ZOIQ and entitled
-r
J�pY 41 C N SID-ODD13neets all the requirements of the Mason
County Resource Ordinance, Landslide Hazard Section, is complete and true, that the assessment
demonstrates conclusively that the risks posed by the landslide hazard can be mitigated through the
included geotechnical design recommendations, and that all hazards are mitigated in such a manner as
to prevent harm to property and public health and safety. (Signatur and Stamp)
MAR j
z �
GIST
ONAL ECG\
JEXPIRES 1-8- /'I--
Page 2 of 2 Form Effective June 2008
Disclaimer: Mason County does not certify the quality of the work done in this Geotechnical Report.
MARTIG ENGINEERING
P.O. Box 11850
Olympia, WA 98508-1850
(360) 754-9687
Fax (360) 705-0789
April 26, 2010
Mason County
Department of Community Development
Public Works
426 W. Cedar
P.O. Box 578
Shelton, WA 98584
Attn: Grace Miller, Planner
Re: Compliance Geotechnical Report for:
* Property Owner: Harstine Island Estates Association
540 E Dana Drive
Shelton, WA 98584
* Contact/Representative: Dave Asselstine (360) 427-8872
* Site Location: Harstine Island
Parcel C on TPN 21901-50-00092 (Lot 40A)
Shelton, WA 98584
(Take SR 3 from Shelton toward Bremerton; Turn Rt on Pickering
Rd; Cross bridge onto Harstine Is; Turn right/South onto Harstine
Island Drive , following it to its Dead-End at Harstine Island
Estates; Turn right onto Dana Drive, following it to the common
Lot-Line between Lots 36 & 37 where you Turn right onto Dirt
Road; Follow the Dirt Road to the Site, located at the Dead-End
of the Dirt Road (see the Attachment 1 Vicinity Map).
* Tax Parcel No.: 21901-50-00093 (Lot 40A);
* Mason County: Sec 01, Township 19 N, Range 02 W;
* County Permit Numbers: DDR2009-00049
* Proposal: THE EMERGENCY REPLACEMENT of the two existing
deteriorated/failing Redwood Water Storage Tanks with one New
Prefabricated and Coated Steel Tank, accompanied with the
placement of its required companion Booster Station (that is a New
Prefabricated and Pretested Package Station).
Dear Ms. Miller:
1
I, Kenneth W. Martig, Jr., PE, of Martig Engineering have completed my engineering
investigations regarding the requested Geotechnical Report associated with the above
referenced Tank Replacement Project on the relocated Harstine Island Estates
Association (HIEA) 40' x 40' Utility Lot.
PROPOSED ACTION (Emergency Replacement of Failing Water Storage Tanks)
The Proposed Action at this site is to prepare the Utility Lot for the Placement of one
new prefabricated Water Storage Tank and the placement of the necessary new
prefabricated companion Booster Station. The Attachment 3 Site Plan shows the
placement of the new facilities.
A full description of this Project is attached at the end of this Geotechnical Report, after
the nine report attachments.
The access easement driveway, into the property, was constructed in the early 1970's
and remains in satisfactory condition.
The new replacement tank and accompanying booster station will be connected to the
existing piping and electrical facilities currently serving the old tanks and booster station
that are being replaced.
A new FIRE HYDRANT will replace the Fire Truck old Fill-Port. The new hydrant meets
the new requirements of Fire District #5 and will be located along Dana Drive at the
current Site of the existing Fill-Port being replaced.
SUMMARY
All slopes greater than 15%, within 300-feet of the Site, are controlled by a deep
cemented Till soil, inherent at shallow depths within the present Sinclair series soils.
Therefore, these existing slopes are very stable.
Ground slopes greater than 40% are located essentially 300-feet from the Utility Lot
being studied, as shown upon the Attachment 5 Elevation View.
As the original Design Engineer for this Water System in 1972, 1 am familiar with the
Site over a 38-Year period. The Site was deemed stable then and remains stable now,
based upon our recent investigations documented within this Geotechnical Report.
As a result of our investigations, we can affirm that all potential Landslide Hazards can
be overcome in such a manner as to prevent harm to property and public health &
safety and that no significant Environmental Impacts will result if this Proposed Action is
permitted as outlined within this Geotechnical Report and its attachments.
2
The following discussion summarizes our: Site Investigations; Research of Site
Conditions; Analyses; and Conclusions, allowing this Geotechnical Report to be
completed for the above referenced site.
GEOTECHNICAL REPORT
1. Geologic Conditions:
a. Topography-- An enlarged section of the Mason County Web Site Map shows
the general topography of the site and its surrounds (see Attachment 4). The
contours on this Map and the Attachment 7 Coastal Zone Atlas Map show that
the Site is located along the 180-foot contour on the top of a north-south ridge.
The onsite slopes were measured to be only 7%. Slopes increase as you move
either westerly or easterly from the Site. Only when you reach a distance of
essentially 300-feet from the Utility Lot do the slopes exceed 40%.
The Attachment 5 Elevation View shows the measured topography and critical
slopes of the property in greater detail.
No evidence of surface water runoff was found tributary to the Site, or leaving the
Site, since the Sinclair series surface soils readily infiltrate falling precipitation.
h. Soils Types-- The Mason County Soils Survey shows two classifications of soils
that influence this site (see Attachment 6):
(i) So, Sinclair shotty loam, 5 to 15%-- a granular unconsolidated
moderately well draining surface soil layer from 28" to 42" inches thick,
supported by a deep strongly cemented Till, continuous to great depths.
The surface soil above the Till absorbs moisture readily and runoff
is non-existent to slight.
(ii) Sp, Sinclair shotty loam, 15% to 30%-- This soil is similar to the above
So soil, except that the depth to the Till is more irregular.
Soils test pits were dug on the Utility Lot to confirm the elevation of the top of the
Till, for determining the elevation of the bottom of the foundation for the Tank.
The location of the two Test Holes is shown on Attachment 9. Test Hole #1
found the top of Till at Elevation 175.2 and Hole #2 found it at 175.3. The surface
Elevation of the granular surface soil ranges from 178.2 to 176.0.
3
Soils Test Hole #1: Soils Test Hole #2:
c. Ground Water Conditions-- No evidence of a soil layer containing ground water
could be found at or near the site. No signs of groundwater emerging from any of
the site or nearby slopes, either natural or man-excavated, could be found.
During the winter wet season, a very shallow water table condition may develop
on top of the Till layer at the base of the 28" to 42" thick granular surface soil.
This is a minor seasonal temporary condition. Due to the sloping nature of the
property at and near the Site, this water quickly migrates laterally as Interflow
thru the granular upper soils in an easterly direction toward Dana Drive. No water
has been observed flowing from these sloping soils where they meet the westerly
Dana Drive drainage ditch..
d. Related Upslope Conditions-- As shown on Attachments 5, 6, and 7, the
upslope ground runs along a north to south sloping Hogback type ridge with its
north-south slope less than 15%. Since the tributary area is small, and the
upslope ground drains mostly toward the east and west, no measurable surface
or ground waters flow toward the Site.
No surface water bodies (lakes, wetlands, or streams) exist upgradient from the
Site.
e. Surface Water Runoff-- No surface water runoff is tributary to the site and no
evidence of onsite surface water runoff leaving the site was found..
All precipitation falling (on the constructed access driveway and both the existing
developed Utility Lot and the relocated Utility Lot) infiltrates into the granular
surface soil layer. Photographs #5 & # 6 show no signs of surface water flow or
erosion from overland flow.
4
Access with no ditches or runoff signs: No runoff @ Westerly Dana Dr ditch:
q
r ,
The above two Photos show that no Drainage Ditches are necessary at the Site
(left Photo) or below the Site (right Photo), since no overland flow develops.
1'. Noted Landslide Activity-- No signs of any landslide activity were found on or
near the site, either on natural or manmade slopes.
Stereo Aerial Photographs were examined for signs of Landslide activity. None
were found. Attachment 8 shows a 2006 Aerial Photo of the Site area,
highlighting stable Canopy and Understory vegetation.
I, Ken Martig, Jr PE, have been associated with this Site for 38-Years. During
that time, there have been no visible signs of landslide activity on or near the
Site.
2. Site Plan:
a. Development Features-- Attachment 3 shows the relocated 40' x 40' Utility Lot
where the replacement tank and accompanying booster station will be placed.
b. Geologic Features-- The existing stable geologic conditions will remain
unchanged when the proposed facilities are placed as shown. The stabilizing
geologic feature is the uniform uninterrupted Sinclair series soil Till formation.
Since this property lies upon a small north-south ridge/hogback with no surface
water tributary to it, precipitation falling in the vicinity of the Site drains in three
directions (west, east & south) as interflow thru the granular surface soil layer.
All slopes greater than 15% remain stable since they are underlain by the
cemented Till, with no intervening unconsolidated lenses of granular water-
bearing soil discharging spring water onto any slope within 300-feet of the Site.
5
3. Soils Examination:
a. Exposed Soils-- The existing Redwood Tanks, with their accompanying Booster
Station, are located upon an open graded site just west of the site where the
new replacement facilities will be placed. These graded soils are the same as
the soils examined at the replacement site.
The precipitation falling upon the existing facilities (including the two tank roofs
and the booster station roof) infiltrates into the surface soils with no runoff from
the site. This will be the same at the replacement site, especially since the
impervious surface of the replacement tank and booster station is smaller than
what now exists.
b. Test Holes-- Soils test Holes were dug on the property, as discussed in Section
1 above. These test pits confirm the 28" to 42" depth of the upper granular soil
layer and the presence of the underlying Till supporting it (see Attachment 9).
4. Potential Hazard Discussion:
The primary issue, being addressed within this Mason County required Geological
Report, is the POTENTIAL HAZARD posed by existing slopes steeper than 15% to
40% (up to 44.4% at a distance of 300-feet east of this Site).
The QUESTION BEING ANSWERED BY THIS REPORT is whether or not these
slopes do indeed pose a threat to the Proposed Action.
• IN SUMMARY, they do not. They are existing moderate to steep slopes,
maintained stable by the strongly cemented Sinclair series soils Till. All
slopes at or near the Proposed Action have remained stable, as
evidenced by the review of Stereo Aerial Photos, the age of prior existing
nearby stable improvements, and the soils investigations reported herein.
a. Location of Potential Hazard-- The worst case Potential Hazard is shown to be
the 44.4% slope approaching the bottom of an existing ravine over 300-feet
away. It is far enough away that it will have no impact.
Secondarily, slopes less than 40% but greater than 15% exist. The Attachment 5
Elevation View shows that they start approximately 120-feet east of the relocated
Utility Lot. Since they are remote and the stability of these steeper slopes is
controlled by the underlying cemented Till, they are stable and will remain stable,
thus having no impact upon the Utility Lot site.
b. Location of Proposed Action-- The Utility Lot where the replacement facilities will
be placed is on, and surrounded by, land having a ground slope less than 15%.
6
c. Buffer or Setback Requirements-- Given the conclusions from our investigations,
we find no reason to impose new buffers or setbacks at this site. The 40' wide
Site has an existing 120-foot setback from slopes steeper than 15%.
5. Elevation View:
Attachment 5 shows the measured Elevation View (Sections A-A).
This elevation views shows the Utility Lot for the Proposed Action, and its 120-foot
setback from slopes greater than 15%.
Since only two succinct layers of soil exist, within the area represented by these
elevation views, the layers were not continuously plotted along the Section's original
ground line. The upper unconsolidated granular porous soil layer is only 28" to 42"
thick and is present throughout the site The supporting underlying dense
consolidated cemented Till is continuous to deep depths.
6. Slope Stability Analysis:
a. Existing Slopes-- All existing slopes greater than 15%, within at least 300-feet of
the Proposed Action, have been determined to be stable. I have observed the
stability of this land for over 38-Years.
Attachment 7 shows the subject site superimposed upon the Coastal Zone Atlas
stability map for this area. It shows that the Site is located well within land
designated as being "S" Stable.
No slope instability or landslides were found when reviewing historic Stereo
Aerial Photos. Attachment 8 shows a 2006 Aerial Photo view of the stable
Canopy and Understory vegetative ground cover.
The primary technical quality governing the structural stability of the nearby
steeper slopes, found up to 44.4%, is the deep strongly cemented Till formation
inherent with the Sinclair series soils that is present in all of the subject slopes
(either natural or man-made excavations). This Till was confirmed present in all
Potentially Hazardous slopes.
No fill slopes exist and no fill slopes are necessary to implement the Proposed
Action.
b. Disturbing Existing Slopes-- All of the Potentially Hazardous slopes are remote
from the Utility Lot by at least 120-feet. No activity will occur upon slopes steeper
than 15%.
Construction of the elements of the Proposed Action, upon the relocated Utility
7
i
Lot, will be upon slopes measured to be 7%. The Tank foundation will be
constructed on undisturbed Till.
The up-slope ground to the west and north is less than 15% in steepness.
c. Creating New Slopes-- No new steep slopes will be constructed. The Utility Lot
will be graded in accordance with the spot elevations shown upon the Site Plan.
d. Calculations-- Since the stability of the Potentially Hazardous steep slopes is
governed by the Sinclair series Till soil, no calculations were necessary to
support our finding: "that all Potentially Hazardous steep slopes are and have
been stable, and will remain stable if the Proposed Action is approved".
It is our professional opinion that the use of the "Simplified Bishop's Method of
Circles" is not productive with these soils.
Since the Utility Lot has a ground slope of 7% and is setback 120-feet from the
nearest slope greater than 15%, no calculations techniques are useful in
supporting the conclusions presented within the other sections of this
Geotechnical Report.
In terms of Seismic Stability the subject property has remained stable after
experiencing over 20 quakes greater than 5.0 during the 42-year Period from
1928 thru 1970, including a 7.1 Olympia quake in 1949 and a 6.5 Tacoma quake
in 1965 where significant damages occurred around Puget Sound. Documented
damages from these quakes were worse than the damages from the more
recent 2001 Nisqually 6.8 quake where the site remained stable (Data from US
Earthquakes, USD of Commerce, Coast and Geodetic Survey).
7. Proposed Action Development Placement:
a. Drainage-- The existing developed 35-year old Utility Lot, upon which the
existing two Redwood Tanks and Booster Station are located, does not have any
formal drainage system.
No surface water runoff or Tank overflow water has ever exited the Site as
overland flow. All precipitation falling upon the Site (including runoff from the tank
and booster station roofs) has infiltrated into the granular surface soil within the
Site.
However, the newly located 40' x 40' Utility Lot will be graded such that all
surfaces within the Lot drain into a small Retention Pond. No measurable volume
of runoff is expected to reach the Pond (based upon 35-years of observation at
the adjacent existing Site). Any water reaching the pond will exfiltrate thru the
8
Pond walls and flow away from the site thru the ground as interflow.
b. Septic System-- No Sanitary Facilities will be placed at this site. The existing
HIEA Pool House has such facilities for use by the Water System operators.
c. Compacted Fills-- As discussed above, no new fills are necessary or proposed.
Only surface grading of the Site to the elevations shown upon the Site Plan will
occur. Crushed Rock will be placed upon the finish grade within the Lot to
accommodate occasional temporary parking and provide erosion control.
d. Foundations-- As discussed above, new footings and foundation pads are
necessary. All will be constructed upon undisturbed Till.
e. Buffers or Setbacks-- As discussed above, no additional/special buffers or
setbacks are necessary, associated with this Proposed Action, to maintain stable
slope conditions.
8. Clearing and Grading Recommendations:
a. Vegetation Removal-- The vegetation and topsoil have been removed from the
Utility Lot. Only minor Understory vegetation will be removed from the
Construction Easement areas as necessary during construction. All healthy trees
larger than 6" at the base will be preserved.
b. Grading Cuts & Fills-- Excavation is required for constructing foundations. Less
than 200 cubic yards will be excavated for the foundations. This excavated soil
will be used to grade the interior of the Utility Lot around the replacement tank
and booster station. No Structural Fills are proposed or necessary.
c. Revegetation-- Minimal revegetation will be necessary outside of the 40' x 40'
Utility Lot, within the Construction Easement areas. The Utility Lot interior area
floor and the driveway entrance will be covered with 2-inches of crushed rock. All
bare soil areas within the Construction Easement areas shall be covered with
several inches of loose Straw/Hay or coarse Mulch/Beauty Bark. This cover shall
be maintained until natural revegetation occurs.
9. Erosion Control Plan:
Since no runoff currently exists and no offsite runoff is tributary to the site, no
special erosion control plan is necessary.
a. Temporary, During Construction-- A silt fence or a line of staked Straw/Hay
Bales should be placed, as shown on Attachment 9, prior to the start of
construction. It should be maintained until construction is completed and the
permanent erosion control measures are established.
9
b. Permanent Erosion Control-- The driveway and the floor within the Utility Lot
shall be covered with several inches of crushed rock..
All ground surfaces, where large portions of bare earth remain (outside the Utility
Lot and driveway/parking areas), shall be covered with 3" to 4" of loose straw/hay
or coarse beauty-bark, mulch, to prevent erosion.
The remaining Understory vegetation should remain undisturbed, as much as
practical, during installation of the replacement utilities.
The small Retention Pond will be constructed to receive any surface water that
might develop within the Utility Lot, even though none is expected (based upon
over 35-Years of observation at the existing adjacent Utility Lot). Any water
reaching the Pond will exfiltrate thru the Pond walls and flow away from the Site
as interflow within the granular surface soil layer.
10.On-Site and Off-Site Impacts:
a. On-Site-- No adverse environmental impact will occur. The Replacement Water
System Utility Components will be placed at the new 40' x 40' Utility Lot, located
immediately east of the existing Utility Lot. It will be similar in nature to the old
one, which has existed almost 40-Years. It will be newer, and quieter than the
old facilities, hence an improvement..
A new Cedar Fence will screen the interior of the Utility Lot from view. The
Replacement Booster Station will not be visible from outside the fence, and the
fence will help dampen the sound of the operating Booster Station.
b. Off-Site-- No adverse environmental impact will occur. The replacement facilities
will be more remote from an existing Single Family Residence, and be screened
with a new Cedar Fence.
11. Final Proposed Action Development Conditions:
a. No disturbance of slopes steeper than 15% will occur;
b. Healthy Large trees (6' or larger at the Base) located within the Construction
Easement areas will remain;
c. No activity shall occur upon any Private Property outside of the newly located
Utility Lot, the existing old Utility Lot, or the duly designated easements;
d. Reasonable ingress and egress shall be maintained,
along all duly designated
access easements at all times;
e. The provisions of this Geotechnical Report shall be followed, unless altered in
writing by a qualified professional, and any said written alterations are approved
by Mason County.
10
12. Special Mitigation:
No additional special mitigation is necessary associated with this Proposed Action.
The relocated Utility Lot will be screened from view with a gated Cedar Fence, 8-foot
high, and stained with a standard color chosen by the Owner of the nearby
Residence. This Owner will also choose a color for the new Storage Tank from the
standard colors offered by the selected Tank Manufacturer/Installer. Also, the
replacement booster station must be quieter, as specified herein.
13. Final Site Plan Map for Proposed Action:
The Attachment 3 Site Plan adequately shows the relocated Utility Lot and where all
elements of the Proposed Action will be located and constructed. Therefore, no
additional "Final Site Plan Map" is necessary.
Furthermore, the Approved Mason County Permits are sufficient for Mason County
to monitor the above presented Final Development Conditions and know when the
specified construction is finished.
This completes this Geotechnical Report for the above referenced and described
Proposed Action.
I, Kenneth W. Martig, Jr., PE, of Martig Engineering have completed this required
Geotechnical Report as documented within this letter Report and its attachments. I am
very familiar with this site, having been involved with the Site and its surrounds for over
38-Years.
As a result of our investigations, we can affirm that all potential Landslide Hazards can
be overcome in such a manner as to prevent harm to property and public health &
safety and that no significant Environmental Impacts will result if this Proposed Action is
permitted as outlined ithin this Geotechnical Report and its attachments.
WW. artig,
Attachments-
1. Vicinity Map; �c�of WAS.
2. Tax Parcel Map;
3. Site Plan Map;
4. Topographic Map;
5. Elevation View (Section A —A); o
6. Mason County Soils Map;
7. Coastal Zone Atlas Map; ss'ONAL ENG
11
8. 2006 Site Aerial Photo (color);
9. Drainage & Erosion Control Map (Soils Test Holes)
10. Detailed Description of Proposed Action.
12
ATTACHMENT 1 LA M,
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HARSTINE ISLAND ESTATES ASSOCIATION
EMERGENCY REPLACEMENT OF
WATER STORAGE TANKS AND BOOSTER STATION
SCALE: (/�2�0/ APPROVED BY: DRAWN BY Kwr`'�
DATE: /G REVISED •_
N�,avcln 21 Z'a
Martig Engineering
P.O.Box 11850 s 1'} P l A Y\
Olympia,WA 98508-1850
DRAWING NUMBER
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ATTACHMENT 9
Drainage & Erosion Control Map
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HARSTINE ISLAND-'ESTATES ASSOCIATION
EMERGENCY-REP.LACEMENT.OF.
WATER STORAGE TANKS AND BOOSTER STATION
SCALE: ���_201 APPROVED BY: DRAWN BY ✓��
DATE:March 22,2010 REVISED f+ -
Martig.Engineering
P.O:Box 1'1850 DRAINAGE & EROSION CONTROL
Olympia;_WA 90508-1850
DRAWING NUMBER
C-3
Martig Engineering
P.O. Box 11850
Olympia, WA 98508-1850
(360) 754-9687
Fax (360) 705-0789
March 22, 2010
HARSTINE ISLAND ESTATES ASSOCIATION
EMERGENCY REPLACEMENT OF
WATER STORAGE TANKS AND BOOSTER STATION
OWNER
Harstine Island Estates Association
540 E Dana Drive
Shelton, WA 98584
ENGINEER
(Kenneth W. Martig, Jr. PE)
Martig Engineering
1
DETAILED DESCRIPTION OF
PROPOSED ACTION
1. REPLACEMENT DESCRIPTION
a. Replacement Purpose:
The Harstine Island Estates Association (HIEA) has two failing old Redwood
Storage Tanks, originally installed to provide a nominal capacity of 30,000
gallons. This requires replacing the two old tanks with one new Replacement
Tank.
The origin of Coliform Bacteria Contamination, found within the distribution
pipelines, has been traced to these tanks. This contamination is requiring
temporary Chlorination of the Water Supply until the old tanks can be replaced.
In accordance with an agreement made between the HIEA and an adjacent
Neighbor, the new Replacement Tank will be placed at a new location, located
further away from the neighbor's residence.
Associated with placing the new Replacement Tank further away from the
neighbor's residence, the existing Booster Station must also be moved to the
new location. Since the existing Booster Station is too small to meet State
Department of Health standards, a new Replacement Booster Station must be
installed along with the new Replacement Tank.
b. Replacement Discussion:
(1) Site Work:
The new location is a square parcel of land (40' x 40'), connected to the
20-foot wide Access Easement by a 20-foot wide by 10-foot deep
Driveway Easement. This new parcel is located directly across the Access
Easement from the existing parcel where the existing tanks and booster
station are situated. A 20-foot wide Construction Easement exists around
the perimeter of the Site.
Most of the new 40' x 40' Site and the 20' x 10' Driveway Easement have
been cleared and grubbed, with the organic topsoil removed and
stockpiled outside of the Site boundaries, within the Construction
Easement area.
Additional grading is required. Soil excavated when placing the tank's
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concrete foundation and constructing the Site Drainage Retention Pond
will be used as fill within the site. Additional fill will include a small amount
of ballast and approximately 20 yards of crushed rock top course. Once
grading within the interior of the Site is completed, the pile of stored
2
topsoil will be uniformly graded within the Construction Easement area,
creating a smooth transition from the graded Site to the outside edge of
the Construction Easement (sloping such that the resulting grade within
the Construction Easement drains away from the Site).
The existing Access Easement shall be maintained using crushed rock
top course as necessary (Survey Control Points must not be disturbed
unless reference points are set by a Licensed Surveyor).
A Cedar Fence with gates shall be installed around the Site perimeter
once all other construction is completed within the Site.
(ii) Replacement Tank:
The new Replacement Tank should be a nominal 60,000 gallon standard
sized steel tank (standard dimensions in the range of: 21.54" inside
diameter; 24.55 eave height; and be pre-manufactured and coated (15-
year coating warrantee inside and out) for field erection-assembly on the
new foundation installed within the Site. The tank shall have all necessary
standard fittings and accessories and must meet all Washington State
Department of Health, AWWA, and OSHA requirements for the purpose
of storing Potable Water.
The foundation for the tank shall be a reinforced Portland cement
concrete Ring with compacted ASTM C-33 coarse sand within the ring, all
in accordance with the tank manufacturer-installer. The Ring is 2-feet wide
and 3-feet deep with an inside diameter 2-feet less than the tank
diameter.
The number and size (if any) of anchor bolts shall be as specified by the
Tank manufacturer. They will be inserted into the foundation by drilling
holes and be attached to the foundation with epoxy glue.
(iii) Replacement Booster Station:
The Replacement Booster Station shall have the capacity to supply a
flow demand that varies from 0 to 80 gallons per minute , while
maintaining a discharge into the pressure zone distribution piping within
the range of 55 to 60 pounds per square inch (this replaces the original
1973 DOH approved 73 gpm at a 60 psi booster station).
The Replacement Booster Station shall be a complete-package unit,
completely assembled, contained within a weatherproof-heated
housing, pre-tested to meet performance requirements, and ready to be
placed upon a concrete pad foundation such that the Replacement
Booster Station can be placed into service by simply connecting it to the
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available Site power supply and existing connecting piping at the new
tank Site.
The Replacement Booster Station shall have all necessary standard
appurtenances and accessories, a flow meter, be UL approved, and
must meet all Washington State Department of Health, AWWA, and
OSHA requirements for the purpose of delivering Potable Water.
The Replacement Booster Station shall be quiet during all operating
conditions, with the target noise level no greater than 50 to 55 dBA at a
distance of 50-feet from it. However, an 8-foot high Cedar fence will
contain the unit. If this will reduce a higher level of sound to 50 to 55
dBA at a distance of 50-feet, the noise level limit is satisfied.
If the weatherproof housing is made of steel, welded seams, that can
become wet, must have continuous welds (not stitched) in order to
prevent corrosion of metal that cannot become coated during the
application of the surface protection coating.
(iv) Piping Connections:
The existing pipes that the Replacement Tank and Replacement
Booster Station must be connected to are located within the 20-foot
wide Access Easement between the existing Site and the new Site.
Field locate the respective existing pipelines within the Access
Easement and install the following piping iping connections:
• the 3-inch Supply pipe to the Replacement Tank (this pipe transfers
water both into and out of the Tank and supplies water to the
Booster Station);
• the 2-inch Pressure Zone Supply pipe to the Replacement Booster
Station discharge pipe.
These connections must be routed such that they pass within the
confines of the new 20' wide by 10' Driveway Easement that connects
the Access Easement to the new Site. Provisions for abandoning the
pipes, that lead to the old Site from the Tie-Points, must be incorporated
in order to abandon the pipe during demolition of the old Site..
The new pipe connections that must be made within the Site include:
• the 3-inch Supply pipe that connects the suction side of the
Replacement Booster Station to the 3-inch Replacement Tank
Supply pipe;
• a freeze-proof outdoor Hose Bib.
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The existing Fire Truck water supply Fill-Port, located along Dana Drive,
must be replaced. It is to be replaced with a new Drafting Hydrant, fitted
with a 5-inch Store Adapter and painted Red.
(v) Electrical Connections:
The existing power supply to the old Site, located within the 20-foot wide
Access Easement, is a 240-Volt Single Phase, Secondary Power Line
(direct bury wire) from a power pole mounted Meter, located down at
Dana Drive (next to the Fire Truck Fill-Port).
Field locate this existing direct bury power supply and splice in a new
Power Feed for supplying power to the new Site. Provisions for
terminating power to the old Site from the splice location is necessary in
order to terminate power to the old Site when it is abandoned. This new
power feed to the new Site must be routed such that it passes within the
confines of the new 20' wide by 10' Driveway Easement that connects
the Access Easement to the new Site. This new Power Feed will
connect to the Power Panel located within the new Replacement
Booster Station.
New electrical wiring will include:
• Providing a 120-Volt power supply for the Wireless Banner Well-
Pump Control Instrumentation, that will be moved from the existing
booster station to the new one;
• Providing a weatherproof outdoor duplex 120-volt power outlet (field
located);
• Providing a manual- switch operated Outdoor Yard Light;
• Mounting a Lightning-Rod on the Replacement Tank and wiring it to
a new Ground-Rod to protect the new Replacement Tank;
• Providing and wiring two Float Switches within the new Replacement
Tank and running Control Wire from them to the Banner Node unit
that is to be mounted within the new Replacement Booster Station;
• Mounting the Banner Antenna on top of the new Replacement Tank
and wiring it to the Banner Node Unit relocated within the new
Replacement Booster Station, using the existing 50-foot wire
antenna lead.
(vi) Instrumentation:
A dedicated, buried, low voltage hard-wire lead (two-pair Telephone
Wire) exists, running underground from the old Tanks to the Well Pump
House. Field locate this wire, that is buried within the 20-foot wide
Access Easement, and splice a new extension onto it. This extension
will connect the existing wire to the instrumentation panel located within
the new Replacement Booster Station.
5
The existing Banner Instrumentation, located at the old Site, will be
relocated to the new Site once the new facilities are disinfected, tested
and approved for use. The equipment that will be relocated includes:
• the existing board mounted Banner Node Radio assembly shall be
moved to a new Instrumentation Panel (field located) to be placed
within the new Replacement Booster Station;
• the existing board mounted Radio Re-Boot assembly shall be moved
to the new Instrumentation Panel placed within the new
Replacement Booster Station;
• the existing Banner antenna shall be moved from the top of the
existing tank to the top of the new Replacement Tank.
(vii) Drainage and Erosion Control:
Since 1973 to date, no runoff from the existing tank storage Site has
occurred. The soils readily infiltrate the runoff falling upon the Site,
including that from the two tank roofs and the booster station roof.
The new 40' x 40' Site has the same soils as the old 40' x 40' Site.
However, a new drainage Retention Pond will be installed on the new
Site. The new Site will be graded such that all of the Site will drain to
this new Retention Pond, including the new Replacement Tank overflow
(the existing tanks have never overflowed and the new tank will have a
redundant off switch to insure that it will not overflow).
The new Site was cleared and grubbed in the Fall of 2009, in order to
obtain soils information for the Geotechnical Report. Observations thru
the 2009-2010 Winter confirm that no Surface Water Runoff is tributary
to this new Site and that the new Site does not generate Surface Water
Runoff that could migrate onto adjacent property (the same conditions
were observed at the old Site as they have been for 38-Years).
Although 38-Years of observation confirm that no Drainage or Erosion
Control measures need be applied during construction or after
construction, note that a Retention Pond is being constructed as part of
this project and temporary erosion control Silt Fencing is recommended.
(viii) Demolition at the Old Site:
Once that the new facilities have been in operation (without problems,
for a period of two weeks), the two existing Redwood Tanks shall be
removed along with all of the contents within the existing Booster
Station Building. The Contractor shall consider any salvage value as a
credit , when preparing their Bid for demolition.
6
The connecting pipes and power to the old Site shall be abandoned in
place, using the abandonment schemes put in place when the
respective new utility ties were made for the new Site.
The existing Booster Station Building and one of the concrete
foundation pads for the redwood tanks will be saved, as-is, at the
request of the adjacent property Owner.
7