CANOD.pdfCity of Edmonds
Critical Area Notice of Decision
Xp-plicantProperty
Owner:
Critical Area File
2q,�)6 - (�X) e'7 2-
Permit Number:
626, -2, e ( 3 c> W7 'v
/05 3
Site Location:
'J
Parcel Number:
Project Description:
S COY � C.
[:] Conditional Waiver. No critical area report is required for the project described above.
1. There will be no alteration of a Critical Area or its required buffer,
2. The proposal is an allowed activity pursuant to ECDC 23.40.220, 23,50.220, and/or
23.80,040.
3. The proposal is exempt pursuant to ECDC 23.40.230.
❑ Erosion Hazard. Project is within erosion hazard area, Applic,nt must pre are an erosion and
iV
sediment control plan in compliance with ECDC 18.30.
(/,) 7 " e o
10Critical Area Report Required e proposed t isthicritical area and/or a critical area/I
, project win a LA
buffer and a critical area report is required. A critical area report has been submitted and evaluate"
for compliance with the following criteria pursuant to ECDC 23,40.160:
I The proposal minimizes the impact on critical areas in accordance with ECDC 23.40".120,
Mitigation sequencing;
2. The proposal does not pose an unreasonable threat to the public health, safety, or welfare
on or off the development proposal site;
3. The proposal is consistent with the general purposes of this title and the public interest;
4. Any alterations permitted to the critical area are mitigated in accordance with ECDC
23.40. 110, Mitigation requirements,
5. The proposal protects the critical area functions and values consistent with the best
available science and results in no net loss of critical functions and values; and
6. The proposal is consistent with other applicable regulations and standards.
❑ Unfavorable Critical Area Decision. The proposed project is not exempt or does not adequately
mitigate its impacts on critical areas and/or does not comply with the criteria in ECDC 23.40,160 and
the provisions of the City of Edmonds critical area regulations. See attached findings of
noncompliance,
Favorable Critical Area Decision. The proposed project as described above and as shown on the
attached site plan meets or is exempt from the criteria in ECDC 23.40,160, Review Criteria, and
complies with the applicable provisions of the City of Edmonds critical area regulations. Any
subsequent changes to the proposal shall void this decision pending re -review of the proposal.
❑ Conditions. Critical Area specific condition(s) have been applied to the permit number referenced
above. See referenced permit number for specific condition(s).
Reviewer
Signature
Date
Appeals: Any decision to approve, condition, or deny a development proposal or other activity based on the
requirements of critical area regulations may be appealed according to, and as part of, the appeal procedure, if any,
for the permit or approval involved.
Revised 12/16/2010
1A U,"
&
ASSOCIATES,
INC.
Sepwnher M 201 �
IMI-, Scoll Schriebe'r
761 Dalcy Strce-t
F'(finonds. \VA 9S'020
Dcat• Nfr. Schricher;
SUbjed: Geolculadcal luvemigadon and RveNnowndmions
1':.InIhI'cchI Short I'Lli
9441 Qmpiv Vivu Drive
Unk Job NO. 1106 1
I NT1,10 1) 1 J CTI ON
At &IOUY R-(ItW-St. we Me conjKleted a geotechnical in"'U'Stigation f -'6r tbe proposed slhor�
plat, located "11 the abo%,e itc1drk;ss in L.cjrn,ollds� Lo
iss;ucs,: I,) setback am the sicep skTc & Me southeast corner are�.t of the plat 'and 2,)
kadbUity of onsite stornmater disponk The geneml kwa6un of the jAat whe is show's m
P I i 1) 1
lo tc I Vicinky Map. amwhcd hereto, Prescni-ed in this repov! are c)ur --, di
conclusion and recoirinicridations on these issucs,
PROJECT DESCRIPTION
We undei:tand that the propose.ddevelopm.en', Im iiu, iz' to p1m it into tvvv
fwnily building, lots stackt�d in a nordysmAh orientatiom vokk a new 0,1AWAly
reMdawe conswumd on each of the lots. For our use in HAs hwemigmM you prmidext
its Nvith 'a IOP('Igmpwc sumey Phm ofthe phal site. As shown on this pion. presented on
19213 Kentake Place NE - Kenmore, Washington 198028
Phone (425) 48x•- 1 a (425) 48G-2746
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Larlibrec-lit Short Plat
L&A Job til.). Il -)6a
1.a g c 2
11-11(e 2, an arela kvill, ilorae oj'4011�o 01' (llORI IS� filapped at thc southeast corner cd (lu
[ �' 'A
te.
This steep slope harely extends into the sub'ji"Cl plat si'O"% JjltscibOck of propc'sed
de,velopment tioni this steep sloped area needs to I)e deteniiined- ().nsne disposal of
storin runotTeollected over irnpery l Oils surlaces ofthe proposed developlileill is plallned.
Feasibility or utilizing infiltnatlon trenches, located in [tic lovlving area at lhQ north end
o -1 1 iliesile. is to be evaluated -
TO aellieve t1w above purpose, -vc propose a scope olservives comprising spv0fluilly Clic
t,olloxving:
I. Revie�N, 2colo,_Yic and sod conditions at and in, the vicinity of the subjmi propert�
based on a published geologic rriap.
2. Explore StAbsiirfacc (soil and groundwater) conditions in thi� Eirca of Proposed
infiltration trenches cif the mte A,ith back -hoe tes;tpits to depths -where a soil zoraturn
suitable lor slormwater 4)filtration is encountered or it) the maria ium depth lkabout
10 feet) capable bN1 the back -hoc used in test pit excavation, �k hit he occur i M'st,
3Corldt.ld laboralory, gradation tests. 41 accordance with AS"I'M D422). on tv,() ,oil
samples obtains- frorn a targeted soil stratum in the test pigs. The test results are
to be used in determining the de -sign infiltration rate of the target soil sirkILUITI R111, III
-i=, -
accordatwe ivith USDA Texture Ti 1,1c, Per
Ecology 14005 Storaiwater Design Manual fWestern Washhigtr}tl.
4, Prepare a written report to present our findings, conclusions and geoteclinical
recommendations for the design of -infiltration trenches.
LIE & ASSOCIATES, MC.
September 11. 2011
Larnbreclit Short Flat
L&A Job No, 11-061
Page 3
SITE CONDITIONS
Surface Condition
The site is situated on the rnid-slope ofa v�--e-stcrlyto northwesterl'y declining, modentic to
I I
steep hillside overlooking Browns Bay of Puget Sound. It is bounded by Kairez DdN"e (a
private road) to the east, a joint -use paved driveway to the west, and adljoint�d by
family residences to the north and swarth.
Aceording to the topographic map of the site provided to us, the terrain within 111C site
generally slopes down gently westerly at about 5 to 18 percent
I guade, In the Southeast
comer area of the site, the ground slopes down northwesterly at 40 percent or n1ore lioln
off the site to about 2 to 3 feet inside the site., then moderates to about 18 to 33 percent as
it continues further into the site. In the north end area of the site, the ground descends
northward at about .1 S to 1-9 percent grade.
A house and a detached garage currently occupy the central cast sidelof the site. We
understand these existing stnictures are to be demolished to make way for the propw5vd
development of the site. The garage is accessed via a gyavel-stirfaced drive -way, centering
the site at its southwest comer. The open area around the house and the garage is mostly
covered by lawn grass. Dotting throughout the site are mature. very large and tall,
evergreen mid deciduous trees, TMek brush covers the ground along the north and cast
boundary area; of the site.
LIU & ASSOCIATES, INC.
Septcniber 11. 2011
Tinbreclit Short Plat
L&A Job No, 1 1-06 1
Page 4
Geologic setting
The Geo o is Mgp of the Edmonds Fast and Part of the Edmonds West _Q11adrangle
Washington, by James P, Minard, published by UJ. S. Geological Stirvey in 1983, wits
referenced for the _geologic and soil conditions at the residence site, According to this
publication, the surficial soil units at and in the vicinity of the suklect plat are mapped its
a Transitional Beds (Qtb) soil unit underlain by an 01yrnpia Gravel (Q0 g) Soil uniT.
The transitional beds soil unit is composed of* glacial and non -glacial deposits consistjnv,
mostly of massive, thick or thin beds and laminae of gray to dark -gray fine -sandy to
clayey silt. The fine-grained transitional beds soils were deposited in lakes at sonle
distance away from the ice front and in fluvial systems prior to the advance of the glacial
iThe sediments were mostly deposited durin the transitional period near the close of
ice. 9
pre-Praser interglacial (Oly pia Interghaciation) tinic and into early Fraser glacial title.I ni
The transitional beds deposits generally are very -stiff to hard and of extremely lovv
permeability in its natural, undisturbed state. This soil unit, however, was not
encountered in the test pits excavated on the site
The Olympic gravel soil unit is composed of stratified sand and gravel with very mite
amount of silt and clay, deposited during the Olympia interglaciation. Due to their
generally granular composition, the deposits of this soil unit are of moderately high
1 1• permeability and drains well. The deposits had been glacially ove"idden and are
generally dense to very -dense in their natural, undisturbed state. except the top few feet of
soils -which are normally weathered to a loose to rnedium-ftnsc state. The underlying
V
LW & ASSOCIATES, INC.
September I 1 2011
Ila mbrecht Short Plat
L&A Job No, 11-061
Page 5
fresh Olympic gravel deposits in their native undisturbed state can provide good
foundation SUPPOTt With little settlement expected for tight to moderately heavy structures.
Soil Condition
Subsurface conditions in the area at the north end of the site were explored with t%vo test
pits. These test pits were excavated on August 29.. ?01 i, with a rubber -tired backhoe to
depths of8t.0 and 7.5 1eet. The approximate locations of the test pits are shown oti Plate 2
- Site and Exploration Location Plan. The test pits wcrc locatcd with cithcF a wpc
measure or by visual reference to existing topographic features in the field and on the
topographic survey it and their locations should be considerQd ont.", accurate to die
nicasuring method used.
A geotechnical engineer from our office was present during subsurface ,exploration.. wflo
examined the soil and geA)lo gic conditions encountered and COMPAeTed logs of IcsT pits,
Soil samples obtained From each soil layer in the test pits were visually classified in
general accordance with United Soil Classification System. a copy of which is presented
on Plate 3. Detailed descriptions, of' soils encountered during, site exploration are
presented in test pit logs on Plate 4.
Both test pits encountered a layer of loose organic topsoil from 12 to 18 inchcs.thick.
tWerlying the topsoil is a layer of weathered soil of loose to medium -deme, slightly
. I W
silty, fine sand., with a trace of fine gravel and some roots. about 2.0 to 18 feet thick. The
weathered soil is underlain to the depths explored by a dark -brown but clean deposit of
LIU & ASSOCIATES,, INC.
Septleniber 11. 2011
Lainbrecht Short I'lat
L&A Job No, I.1 -t161
Paae 6
dense, medium to coarse sand, with a trace ol'i-Ine gravel. This deposit is interpreted as
the 01yrnp i c gravel sail unit.
I I -
Groundwater Condition
Ciroundwater was not encountered by either test pits excavated on the site. The topsoil,
-weathered soil and the underlying Olympic gravel deposit are all of moderately high
pernicabiliti, and would allow siormwater to seep through easily. Water infiltraling into
the ground would perch on the surface of a low-pernicability fine-grained dcpwift at -.wVh
depth that it should have rninirrial or no inipact on the Iffinctioning of the proposed
infiltration trenches.
DISCUSSION AND RECOMMENDATIONS
ONSITE STORMWATER DISPOSAL
General
.used on the soil condition encountered by the test pits excavated on the plat site, it is our
nd soil
opinion that the fresh Olympic gravel deposit of cle=an mediun-i to coar.se 8 a ender
the north end of the site at shallow depth should be able to support the proposc-d
infiltration trenches for disposing stormwater onsite. Construction of the infiltnation
trenches should be monitored by a geoteQhnical engineer.
. I . Particle Size Distribution Tests
Two soil samples, obtained ftorn Test Pit I at 5.0 feet (referred to as Soil Sw-nplc 1) and
Test Pit 2 at 4.5 feet (referred to as Soil Sample 2) below grade, were selected for Particle
LIU & ASSOCIATES, INC.
September 11, 21111
Lanibre-cht Short Pit -it
L Job No. 11-061
Page "?
Size Distribution tests in laboratory to determine the infiltration rate of the targeted
Olympic gravel deposit. The reports of these tests are presented on Plates A- I and � 2 in
the attached APPENDIX
As shown on the Particle Size Distribution test reports, both soil samples were composed
of gravelly fine to coarse sand, with as clay content of 4.91NO and gravel/sand content of
91.0% for Soil Sai-nple 1, and clay content ol'3,0% Lind gravel/'sand content of 903% for
Soil Sample 2. According to the USDA Texture 'I'riangle (from U.S. Dcpartment of
Agriculture) chart'. shown cats Plate A-3 in the attached Appendix. both soil samples can
be classified as -'sand!'. .
Design Infiltration Rate for Infiltration Trenches
The Stonnwater 005 Edition. publislicd
byWashington State Department of Ecology
W . . is used to estimate the design infiltration
rate of the target soil for infiltration trenches to be constructed at the north end of the
plate site. According to the table of Recommended Infiltration Rates Riv,;ed on USDA
Soil Textural C1g§,s_jfiwjiqn shmvn on Plate A-3. the short -teen infiltration rate is
estimated to be 8 iph (inches per hour) and the longtcrrn infiltration rate 2 ipb fbr both
soil samples classified as "sand-.
4of 10%
As shokv--n on the Particle Size Distribution test reports, the Dlfj size (the size L I
passing) is 0,08-14 inch for Soil Sample I and 0.0786 inch for Soil Sample 2. According,
to the table of Alternative Rccomrnended Infiltration Rates Based On ASTM Gradation
LIU & ASSOCIATES, INC.
September 11. X011
Lanibrecht Short Plat
L&A Job No. 1 1 -061
Page 8
Testing presented on Plate A-4, the estimated long-term infiltration rate is 1-58 iph for
Soil Sample I and 1.49 iph for Soil Sample 1
Based on the above, we recoinniend a design infiltration rate of 1.5 iph be used for the
design of the infiltration trenches to be constructed in the north end area of the site,
Infiltration Trench Construction
The trenches .should be cut at least 6 inches into the underlying clean sand ol'Olympic
gravel deposit. To reach this target soil layer the infiltration trenches would have to be
excavated at least 4.5 feet deep. The soil unit at bottom of infiltration trenches should be
verified by a geotechnical engineer.
Die infiltration trenches should he set back at least 5 feet front property lines. at least 8
feet from nearby building foundations, and at least 1-0 feet frorn the top of the sleep slope
of 40% or more. The soil unit and trench cut bank stability should be vcrirled bv a
gcotechnical engineer during excavation.
The schematic presentation of an infiltration trench with a single dispersion pipe is shown
on Plate 5. The infiltration trench should be at least 24 inches wide. 'I'lic selicmatic
presentation of an infiltration trench with multiple dispersion pipes is shown on Plate 6.
MiAtiple dispersion pipes, if used in an infiltration trench-, should be placed at least 2 feet
off the trench walls and spaced at no closer than 4 feet on centers.
LIU & ASSOCIATES, INC.
September 11. -1011
Lambrecht Short Plat
L&A Job NoI 1 -061
Page 9
The side walls of the trenches should be lined with a laver of non -woven filter Eabric,
such as MIRAFT 1=10 S, The trenches are then filled with clean vvasbed 3/4 to 14' inch
gravel or crushed rock to within about 10 inches of the finish grade. Ale dispersion pipes
should be constructed of 4 -inch rigid PVC pipes and laid level in the gravel or erushcd
rock filled trenches -At about 16 inches below the top cif trenches. "the top of the gravel or
crushed rock fill should also be eovered with the filter fabric liticr. The remaining
trenches should then be backfilled with compacted onsite clean soils. Stormwater
captured over paved driveiNays should be routed into a catch basin equipped with an oil-
Avater separator before being released into the infiltration trenches.
SETBACK FROM STEEP SLOP
According to the topographic map provided to us, a 51cep slope is mappcd at and to the
east of the southeast corner area of the site. This steep slope descends northwesterly, at
grades of 40% or more from off the site to within about 2 to 3 feet inside the east
boundary of the site. then decreases to about 18% to 33% as it continues further into the
site, According, to the above -referenced geologic rnap, and the soils encountered by the
test pits excavated on the site. the site is underlain at shallow depth by dense sand deposit
of the Olympic gravel soil unit. This deposit is of moderate to high shear strength and is
quite stable. it is also of moderately high permeability and would allow storm runoff' to
seep into the ground easily. 1 -herefore, geologic hazards, such as erosion, landslide and
seismic damage should be minimal within the site. It is our opinion that (lie proposed
development for the site may be -set back at a horizontal distance of no less than 10 feet
from the toe of 40% or more slope in the area of the southeast, corner of the site.
LIU & ASSOCIATES, INC.
September 11, 2011
Lambrecht Short Plat
L.&&Job No. 11-061
Page 10
LIMITATIONS
This report has been prepared for the specificapplicatil-m to this project for the exclusive
use by Mr. Schrieber and his associates. representative, consultants and contractors. We
recormuend that this report. in its entirety. be included in the ProJIect contract document!-,
for the information of the prospective contractors ibr their estimating and bidding
purposes and for compliance iv-ith the recommendations in this report during construction.
I'he conclusions and interpretations in this report.. however, should not be construed as a
warranty of the subsurface conditions. The scope of this study does not include services
related to construction safety precautions and our recommendations are not intended to
direct the contractor's methods. techniques. sequence-) or procedures, except as
specl-fically described in this report for design considerations.
Our recommendations and conclusions are based on the geologic and soil conditions
encountered in the test pits, and our experience and engineering judgi-nent. The
conclusions and recommendations are processional opinions derived in a manner
consistent with the level of care and skill ordinarily exercised by other members of the
profession currently practicing under similar conditions in this area. No waffarity,
expressed or implied, is made.
The actual subsurface conditions of the site may vary. from those encountered by the test
pits. The nature and extent of such variations may not become evident until construction
starts. If variations appear then, we should be retained to rc-cNraluate the
LIU & ASSOCIATM INC.
September 11. 2011
Lambrecht Short Plat
L&A Job No. 11 -061
Page 11
recommendations of this report, and to verify or modify there in writing prior to
proceeding further with the construction of the proposed development,
CLOSURE
We are pleased to be of service to you on this project, Please feel free to contact us if yoll
have any questions regarding this report or need further consultation.
a
Six Plates and Appendix attached
Yours very truly
LILJ &-A�SOCIATES, TNC.
J. S. (Julian) Liu. Ph.D., PR
Consulting Geotechnical Engineer
LILTSOCIATES, INC.
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VICINITY MAP
LI LAMBRECMT SHORT PLAN
9441 OLYMPIC VIEW DRIVE
Geoteahsti t Engineering - Engineering Geology Eaft Science EDMONDS, WASHINGTON
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MAJOR DIVISIONS
GROUP
SYMBOL
GROUP NAME
COARSE-
GRAINED
SOILS
GRAVEL
1110ORE T HAIN` 50-'% OF
COARSE FRACTION
RE:7AINED ON NO 4SIFV'E
CLEAN
GRAVEL
GW
loBELL-GRADED GRAVEL, TO COARSE GRAVFL
GP 1
POORLY-GRADEC GRAVC
GRAVEL WITH
51NES
GM
SILTY GRAVE
GG
-�I.JkyEv GAVEL
MIORE 'rHAN, 50%
RETAINED ON THE,
N",- 2W -SIEV.-
F --SAND
I
MORE TliAN 50% OF
COARSE FRACTION
F-ASSING NO 4 SIEVE
CLEAN
SAND
SW
sp
WELL GRADED SAND, FINE -0 COARSE SAND
PCORLY-GRADED SAND
SAND WITH
FINES
SM
SILT -e SAND
SIC
CLAYEY ,ANC
FINE-
GRAINED
SOILS
SILT AND CLAY
LIQUID LIMIT
LESS THAN 50%,
INORGANIC
ML
� PL T
CL
CLAY
ORGANIC
OL
ORGAINIC SILT. ORGANr�' CLAY
fYll--,RE THAN
PASSING ON THE
NO. 2�4 $iE,.VF
SILTY AND CLAY
LIOUID LIMIT
5011 OR MORE
INORGANIC
MH
SILT OF HIGH PLASTICITY, ELAST!0 SILT
CH
C-LAY,)c HIGH PLASTICITY, FAT CLAY
ORGANIC
OH
CiRGANIC S`LT. ORGANIC SILT
--i-4—
HIGHLY ORGANIC SOILS
PT
PEAT AND OTHER HIGHLY ORGANIC SOILS
I FlEt.0 CLAS'SIF I CATION IS BASED ON VISUAL EXAMINATION
OF SOIL IN GENERAL A --CORDANCE WITH ASTM 02488-83-
Z SOJ,L CLASSIFICATION USING LABORATORY TESTS IS BASED
ON ASTM D2487-83
3 DESCRIPTIONS OF SOIL DENSITY OR CONSISTENCY ARE
13A5ED ON iNTERPRETATION OF BLOW -COUNT DATA, VISUAL
APPEARANCE OF SOILS, ANDIOR TEST DATA,
Gemechnic-al Engineering etVnewUVCIieo)ogy - Eadh Sojence,
SOIL MOISTURE. MODIFIERS:
DRY - AB$EflCE OF MOIST U, R
I E, DUSTY. DRY TO
THE TOUCH
SLfGHTLY MOIST - TRACE MOISTURE, NOT CASTY
MOIST- LAV,--PBUT NO VISIBLE VVATFR
VERY MOST - VERY D*AP, IMOISTURE FELT TO 714E TOUGH
j
A L
LVET- VISIBI E FR -EE WATER OR "TURATED,
USUALLY SOIL IS OBTAINED PROM BELOW
WATER TABLE
UNIFIED SOIL CLASSIFICATION SYSTEM
Is
Gsotnhoftl Engineering - Er4lneeemg GoO409Y - Earth SoionvA
No
FILTRATION TRENCH - SINGLE DISPERSION PIPE
LAMBRECHT SHORT PLAT
9441 OLYMPIC VIEW DRIVE
+1! 11 WASHINGTON
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No
FILTRATION TRENCH - SINGLE DISPERSION PIPE
LAMBRECHT SHORT PLAT
9441 OLYMPIC VIEW DRIVE
+1! 11 WASHINGTON
ME
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LIU & ASSOCIATES,
aeotecftrftal Engineering - 5n9insoring Gool-09Y - Earth Soleno
INFILTRATION TRENCH - MULTIPLE DI&Vj
LAMBRECHT SHORT PLAT
9441 OLYMPIC VIEW DRIVE
EDMONDS, WASHINGTON
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aeotecftrftal Engineering - 5n9insoring Gool-09Y - Earth Soleno
INFILTRATION TRENCH - MULTIPLE DI&Vj
LAMBRECHT SHORT PLAT
9441 OLYMPIC VIEW DRIVE
EDMONDS, WASHINGTON
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aeotecftrftal Engineering - 5n9insoring Gool-09Y - Earth Soleno
INFILTRATION TRENCH - MULTIPLE DI&Vj
LAMBRECHT SHORT PLAT
9441 OLYMPIC VIEW DRIVE
EDMONDS, WASHINGTON
NO MOM
Particle Size Gradation Test Report
Lanibrecht Short Plat
9441 Olympic View Drive
Edmonds, Washington
L&A Job No. 11 -061
LIU & ASSOCIATES9 INC.
1�
ASTM C1 E. Particle'
3 %GRAVEL
� ala UND
FINES
`lei C[}L3ES j--" " e
QRS } Fiht>=tl�0,6
FS RBEt�iiJtR FitiE
5167 ? CLAY
{i.{a 0.0 t.5
45-i7 43a9
4>I 4.9
SIEVE. PERCENT -s—
SIZE j FINE€tPERCEW
_.14i
SPEC.'
PASS'?
(X=NO)
'AM in. 1
O
ivur►its
S!8 in.
9£1.5
LL=
PI*
1/2 in.
99.5 �
DS�r= 1.2
.375 in.
99.5
DI,5= 4.113
#4
.48.5
Ce
=f If1
q7.9
�+
4+�dCS = SP -SM
USC
440
52.9
Remarks
JJ2(w
9.0
0,0326 mm,
6,9
OM -08 I lvF
5.9
0.0120 raw!
5.9
0.0055 nim.
4,9
OM61 mm.
4,9
4.0030 nAM
4.9
€1.r341< tett .
3.0
i
no SPOLi rwatkm g»t>y is�sip
Sample No.. ",, OR Svorne of Sat : Lambrecht Short Plat it] 1-1`61} Crate: 9-9-201.1
Location- Elav JQepth: 5.0'
Chert: Lu$ &Aswiates
Projee '. 2011 LaboT;AUsry't'esting
.zir-fGct hFY3-Ee*t.�-'3ffi+&G"T rn4 �Y..3*'e Sfl� u"...3 Vleiet NO: 0911-28 _ ,.. _—„ Robed Ajkm
soil Desaiption "
PoIlT{.Y &piled rand uith silt
ivur►its
PIL=
LL=
PI*
Doefiicien
DS�r= 1.2
D60:z 0334
06()= 0.398
DI,5= 4.113
010= 0,082 4
CU 649
Ce
Class .t#Ein
�+
4+�dCS = SP -SM
USC
AASHTO=
°A-�
Remarks
no SPOLi rwatkm g»t>y is�sip
Sample No.. ",, OR Svorne of Sat : Lambrecht Short Plat it] 1-1`61} Crate: 9-9-201.1
Location- Elav JQepth: 5.0'
Chert: Lu$ &Aswiates
Projee '. 2011 LaboT;AUsry't'esting
.zir-fGct hFY3-Ee*t.�-'3ffi+&G"T rn4 �Y..3*'e Sfl� u"...3 Vleiet NO: 0911-28 _ ,.. _—„ Robed Ajkm
ASTM C117/136 Particle Size Distributioni u
:�li�.1I► '7/l:iltiiii'
*& cf?BBLE$ 6RAVEL r �6 !AU FINES— s
--.. —
GRS, l3E C � 1fiDt33 FINE i . SILT #J
_-
{1.f1 32A
SIEVE j
S
PERCENT �
1=[NeR j
$PEE�C"
1-s-t�Stgu
_ -
PASS?
;XO1
,_1i2 ill,
100.0
rc,� Lltriit�
:375 in.
99.6
LL=
P
#4
9(U
085= 1.45
410
97.1
Q30- 0,273
D 6- 0.127
940
42.1
Cc= 1,30
42{}{)
93
USC5 = SOS -SM AASHT
0.0324 Item.
7.3
larks
0.0206 Tin,
6.9
0.0120 mm
5.9
0.0085lum.
C9
0.0061 ; m�
; 3.9
0.0030 Wim.
# i.9
0.0012 trim.
3,0
Ld
Somplc No.. 9907 Sour of 5arop[e: [,ambr ht Shut P1At #11<060 Date: 0-9-201 t
Loc:aflow 1 , C;eptb. 4.5`
�lleatt: Z.ui & Asa��:i�l
Pr*ct: 20111- watm TvWn$
lama Mt�y. am"'srr�rrRobertAtkram
...a._.._.
soil Ue l_iRtlar�
Well-gtadvd fswid
with -silt
rc,� Lltriit�
PL=
LL=
P
085= 1.45
[300= 0.733
Cisme= 0.546
Q30- 0,273
D 6- 0.127
��0= 0,0796
Cu= 9.:}2
Cc= 1,30
Ct�iflc"
USC5 = SOS -SM AASHT
r 4 --b
larks
FAC 0,01
Somplc No.. 9907 Sour of 5arop[e: [,ambr ht Shut P1At #11<060 Date: 0-9-201 t
Loc:aflow 1 , C;eptb. 4.5`
�lleatt: Z.ui & Asa��:i�l
Pr*ct: 20111- watm TvWn$
lama Mt�y. am"'srr�rrRobertAtkram
...a._.._.
90
Vlay ,gypCgs
A,
\0 ty
sandy stay.
40
Ob, clay
clay loa I a a, r;
A
sandy Clay loam
20 V
A
sa Dain loarn sill loam
lay N Silt
sand sand V`17/
001
percent sand
USDA Soil Textural Triangle
Table Recomtnended infiltration Rates
based'on USDA loll Textural Classification.
*From WLFIASCE, 1998.
',Short -Term
Correction
Esti mafc& Lono-Titrm
"loll Texturat Qnssirkation,
Infiltration
Factor, CF
(Design) Inffitntion Rate
Rate (in
1 to
Clean sandy gravels and
20
2
grw,rclly sands (i.c., 90�% of
the totaj -oil Sample is
mtaincd in tht- 410 sicve)_
sand
2
Loamv Sand
4
0,5
9,ndy Loam
4
U5
Loam
54
0.13
*From WLFIASCE, 1998.
Correetion factors higher than those provided in Table 3.7 should be
r�
considered for situations where long-term maintenance will be, difficult to
iniplcment, where littic or no pretreatment is anticipated, or wherosite
conditions are highly variable or uncertain. These situations nxtuire tile
use, of best professional judgment by the site engineer and the approval of
C-1
the local jurisdiction. An Operation and Maintenance plan and a financial
bonding plan inay be required by the local jurisdiction.
2. ASTM Gradation IlLestirt, kat Fath frifiltration Facilitieses,
, !
As an alternative to Table 3.7, recent studies by Massniann and Buts hart
(2000) were used to develop the correlation provided in Table I& These
studies compare infiltration measurement-, front ffill-scale infiltration
facilities to soil gradation data developed using the ASTM procedure
(ASTM D422), The primary source of the data used by Massmann and
Butchart was from Wiltsie (1998), who included Ilinited infiltration
studies only on Thurston County sites. However, Massniarin mid Butchart
also included limited data from King and Clark County sites in their
an ' alysis. This table provides recommended long-terni infiltration rates
Haat have been correlated to soil gradation parameters using the AST*M
soil gradation procedure.
Table 3.8 can be used to c�stinlate long-term desii-�n infiltration raids
directly from soil gradation data, subject to the approval of the, local
jurisdiction. As is true ofTable 3.7, the lotig-tent rates provided in Table
3.8 represent average conditions regarding site variabiliql, the degree of
long-term maintenance and pre treatincrit for TSS control. 'I'lic long-term
infiltration rates in I -able 3.8 may need to be de{ re if the site is highly
variable, or if maintenance and influent characteristics are not Nell I
controlled. The data that forms the basis for Table 3.8 was JTom soils that
Would be classified as Santis or sandy gravels. No data was available for
fins r soils at -die firne the table wits developed. 'Dierefore,'J'able 3.8 should
not be tised for soils with a d10 size (10% passing the size listed) less than
0.05 mm i~1,1 -S, Standard Sieve). I
Alternative Recommended Infiltration
Rates nased on ASTM Gradation Testing.
Dio Size from ASTIM D422 Soil
Gradation Test (mm)
Estimated Long -Term (Design)
Infiltration Rate (InAr)
04
03
6J*
02
3.5*
2.0**
0.8
• Not rewmnxadod for treom--A
• k6b,- to SSC,4 wM 4:St,-6 for tr tit st rsrshit ity crit
February 2005 Volume /I/ - Hydrologic Analysis and Flow Control B&fPs
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