HomeMy WebLinkAboutPOTTER HEIGHTS S-5128
CASE NUMBER
DEPARTMENT OF HEALTH AND ENVIRONMENTAL PROTECTION
PLATTING OR PLANNING AND ZONING CASE REVIEW
S-5128
PETITION FOR
DATE RECEIVED
REZONING
SPECIAL EXCEPTION
VACATION
RE~LIBDIVISION
March 30, 1979
COMMENT TO PLANNING BY 4-18-79
OF Potter Heights Subdivision (2 plat maps)
FOR MEETING OF
COMMENTS:
ENVIRONMENTAL SANITATION:
of Cases
PUBLIC WATER NOT AVAILABLE
PUBLIC SEWER NOT AVAILABLE TO SERVICE PETITION AREA.
ENVIRONMENTAL ENGINEERING:
71-014 (9/76)
March 26, 1979
W.O. A18778
Grid 3639
4040 "B" STREET
ANCHORAGE, ALASKA 99503
(907) 278-1551
Mr. A1 Pace
4611 Business Park Blvd.
Anchorage, AK 99503
Sub j ec t:
Shallow Subsurface Investigation for Suitability of
On-Site Wastewater Disposal Systems---A 20-Acre Parcel
Near Potter Creek within the NE 1/4, Section 14,
T11N, R3W, SM, Alaska
Dear Mr. Pace:
We have completed a shallow subsurface investigation on your
20-acre parcel near Potter Creek (see Figure 1). The purpose
of this investigation was to determine the suitability of the
designated area for on-site wastewater d~sposal systems and to
make a preliminary determination of the shallow subsurface
conditions for planning purposes.
CONCLUSIONS
Based on the results of this investigation we believe the
site generally will be suitable for construction of on-site
wastewater disposal systems, in conformance with Municipality
of Anchorage regulations.
Our original exploration program included the placing of
8 to 10 test holes. However, due tO the terrain and deep
snow cover, we were only able to place 5 test holes.
Additional exploration, with percolation tests, should be
conducted after the spring thaw, when access is available.
No bedrock or ground water was discovered during the
exploration, however, the site is in a general area where
bedrock and ground water can be problems. Again, these
conditions should be looked for carefully in the next phase
of exploration. In any event, rock outcroppings, natural
drainage soils, springs, etc., should be avoided when con-
structing disposal systems.
$ 1 2.82 1979
~r. A1 Pace
March 26, 1979
Page Two
DISCUSSION
The subsurface investigation consisted of five testholes, three
percolation tests, and laboratory analysis of soil samples
obtained during the field investigation. The testholes were
drilled with a Nodwell-mounted Mobile Drill B-50 rig equipped
with a continuous flight auger, Owned and operated by Denali~ ·
Drilling, Inc. Drilling of each testhole was under the
direction of Terry Barber,·geologist/field technician, Alaska
Testlab.
To evaluate the soil condi%ions, Mr. Barber logged each hole
while drilling was in operation and.took samples directly off
the auger at varied intervals. Each sample was placed in a
sealed plastic bag to preserve its water content. In the labor-
atory, water content and dry strength were determined for each'
sample. The samples were then placed in arbitrary groups
according to their color, texture, and grain size distribution.
Grain sizs analysis, Atterberg limits, and water content, were
then performed on the composite samples of these arbitrary soil
groups.
Three distinct soil groups were enCountered.
below.
~ROUP A
GROUP B
GROUP C
They are described
is a brown silty gravelly sand with ia trace of clay.
This group is very frost susceptible with a frost
classification of F-3. Its unified classification
is SM. Grain size gradations are shown on Sheet 4.
is a brown silty gravelly sand with some clay. This
group is very frost susceptible with a frost classi-
fication of F-3. Its unified classificationis SM.
Grain size gradations are shown on Sheet 5.
is a brown, poorly graded, silty, sandy gravel found
in the last several feet of Testholes 2A, 3A, and 5.
The observed gravel had a maximum size of 1 inch.
This· group is moderately frost susceptible with a
frost classification of F-l/F-3. Its unified classi-
fication is GM.
The grain size distribution curves show the range and percent by
weight of particle sizes evident in each soil.group. Larger
particles may be present in situ; however, the action of the
auger may exclude them from being sampled.
M~. A1 Pace
March 26, 1979
Page Three
Prelimary evaluation of the area for on-site wastewater treatment
systems was performed. This evaluation was accomplished by
inserting a 3/4-inch PVC pipe in a test hole to assist in
measuring the test hole's, water level. The hole was then filled
with water and left overnight. The next day the hole was refilled.
After refilling, the fall rate of the water over the next 60 minutes
was recorded. This test was conducted in Test Holes 1, 3A, and 5.
These test holes were chosen to obtain representative values
for the percolation rates in the general investigation area.
The following percolation rates were observed using the aforementioned
procedure.
Testhole .Rate (min./inch)
'1 23 ~
3A 20
5 43
Ground water was not observed in any of the five test holes.'
The following figures, tables, and graphs c'omplete this report:
Test Hole Location Sketch .Figure 1
Test Hole Logs Table A
Standard Explanatory Information Sheets 1-3
Grain Size Distribution Curves Sheets 4-5
We trust the above meets your present requirements. If you have
any questions .or if we may be of further assistance, please do not
hesitate to contact us.
Very sincerely,
ALASKA TE STLAB
Jordan E. Jacobsen
Approved by:
Melvin R. Nichols, PE
LaboratorY Manager
JEJ:gla:mm
Test Hole #1
TABLE A
WO #A18778
Date: 3/2/79
Logged by: T. Barber
Depth in Feet
From To
0 1
~.d~ 6 16
Bottom of Test Hole:
Frost Line:
'Free Water Level:
Soil Description
F-4, broWn Peat, frozen, Pt.
F-3, brown~ty gravelly Sand,· wet, sharp
particles,~ Group A. ~~
F-3, brown silty gravell ra~.~
from 5' to 6', low to me~.~~~, stiff
to hard, sharp partic~4,~ro~p.B.__ __ _ '
1 ft.
None
Sample Depth
1 5
2 10
3 16
Type of Dry
M% SamPle Strength Group Unified
11.8 G L A SM
12.9 G M/H B SM
11.9 G M .B SM
Remarks: 1'.
3
4
5.
6.
Type of Sample, G=Grab, SP = Standard Penetration,
· U = Undisturbed.
Dry Strength, N=None, L=Low, M=~edium, H=High.
Group refers to similar, material, this study only.
General I~formation, see Sheet 1.
Frost and Textural Classification, see Sheet 2.
Unified Classification, see Sheet 3.
Test Hole #2-2A
TABLE A
WO #A18778
Date: 3/1/79
~/L0gged by: T. Barber
Depth in Feet
From To
Soil Description
0 1.5
1.5 7
F-4, brown Peat, Pt. ·
F-3,~ brown silty gravelly Sand, ~t_~sa-tur'ate~
low to medium density, subrounded--to rounded
particles SM; Group A.
7
:9 15
Transition zone from sand to gravel.
F1 t~ F3, brown silty sandy Gravel, ~
a-t~r_~~, high density, sharp to subrounded
articles, GM, Group C.
Remarks: Moved from TH2 to TH 2A due to refusal at 9 ft. Drilled
2A 15 ft. West.
Bottom of Test Hole:
15 ft.
Frost Line: 1 ft.
Free Water Level:
None
Type of Dry
Sample Depth M% Sample Strength Group Unified
I 3.5 Sat. G L/M A SM
14.9
2 9 G L/.M A SM
2A
Remarks:
15
1.
2.
3.
4.
5.
6.
Sat.
12.9
8.1 G L C GM
Type of Sample, G=Grab, SP = Standard Penetration,
U = Undisturbed.
Dry Strength, N=None, L=Low, M=Medium, H=High.
Group refers to similar material, this study only.
General Information, see Sheet 1.
Frost and Textural Classification, see Sheet 2.
Unified Classification, see Sheet 3.
Test Hole #3A
T~BLE A
WO #A18778
Date: 3/1/79
Logged by: T. Barber
Depth in Feet
From To
0 1
1 7
7 10
10 15
Soil Description
F-4, brown Peat,
F-3, brown silty gravelly Sand, damp.to wet,
high density, sharp particles, SM, Group B.
F-3, brown silty gravelly Sand ~amp to wet,
high density, sharp particles, SM, less
gravel than interval directly above, Group B.
F-'2, brown silty sand Gravel, damp, high to
very high density, sharp particles, GM,
Group C.
Bottom of Test Hole:
Frost Line:
Free Water Level:
15 ft.
1 ft.
None
Remarks: Moved from TH3 to
TH3A due to refusal,at 5 ft.
Drilled TH3A 50 ft. south.
SamPle Depth
1 5
2 10
3 15
Type of .Dry
~{% Sample Strength Grou~ Unified
13.1 G VL/L B SM
11.9 G M B SM
10.0 G L C GM
Remarks:
1. Type of Sample, G=Grab, SP = Standard Penetration,
U = Undisturbed.
2. Dry Strength, N=None, L=Low, M=Medium, H=High.
3. Group refers to similar material, this study only.
4. General Information, see Sheet 1.
5. Frost.and Textural ClassificatJ. on, see Sheet 2.
6.. Unified Classification, see Sheet 3.
Test Hole #4
TABLE A
WO #A18778
Date.: 3/1/79
Logged by: T. Barber
Depth in Feet
From To
0 1.5
1.5 5
5 16
Soil Descrip%ion
F-4, brown Peat,. frozen Pt. ·
F-3, brown silty gravelly San~, well graded,
/d3~~sof~, high density cohesion,
~-~M~ Group A.
F-3, brown silty gravelly Sand, wet, hard
cohesion, high density, interbedded with
gravel layers, g~avel content increased
with depth, SM, Group B.
Bottom of Test Hole:
Frost Line:
Free Water Level:
16 ft.
1 ft.
None
Sample Depth
1 5
2 10
Type of Dry
M% Sample Strength 'Group Unified
12.3 G VL/L A SM
15.6 G M B SM
Remarks:
1. Type of Sample, G=Grab, SP = Standard Penetration,
U = Undisturbed.
2. Dry Strength, N=None~ L=Low, M=Medium, H=High.
3. Group refers to similar material, this study only.
4. General Information, see Sheet 1.
5. Frost and Textural Classification, see Sheet 2.
6. Unified Classification,. see Sheet 3.
Test Hole #5
TABLE A
WO #A18778
Date: 3/2/79
Logged by: T. Barber
Depth in Feet
From To
0 1
'3 5~8 13
Z ~13 16
Bottom of Test Hole:
Frost Line:
Free Water Level:
Soil Description
F-4, brown Peat, frozen, Pt.'
F-3, brown silty g~avelly Sand, fine to medium
sand, wet, medium density, sharp particles,
interval becomes more gravelly with depth,
SM, Group A.
F-3, brown silty gravelly Sand, fine to
medium sand, ~ medium density, sharp
particles, sli~htiy more gravelly'than the
above interval, SM, Group B.
F-3, brown silty Sandy Gravel, wet, medium
density, sharp particles, very ha~d drilling,
GM, Group C.
16 ft.
1 ft.
NOne
Sample Depth
1 5
2 8.5
3 16
Remarks: 1.
e
4.
5.
6.
Type of Dry
M% Sample Strength Group Unified
14.6 G L A
14.1 G M/H B
11.7 G M C
SM
SM
GM
Type of Sample, G=Grab, SP = Standard penetration,
U = Undisturbed.
Dry Strength, N=None, L=Low, M=Medium, H=Hi~h.
Group refers to.similar material,.this study only.
General Information, see Sheet 1.
Frost and Textural Classification, see Sheet 2.
Unified Classification, see Sheet 3.
Test Hole Log - Description Guide
The soil descriptions shown on the logs are the best estimate of the soil's·
characteristics at tbe time of field examination and as such do not achieve the
precision of a laboratory testing procedure. If the log includes soils simples,
those samples recetve an independent textural classification in the laboratory
to verify tb~ field examination.
The logs ofien include tbe following items:
Depth- Interval - usually shown to 0.1 foot, within that zone no
significant cbat~ge in soil type was observed through dri!l action, direct
obserw~tion or sampling.
Frost Classification -~ NFS, Fl, F2, F3, F4, see "Soil Classification
Chart"
Texture of Soil An engineering classification of the soils by particle
size and proportlon, see "Soil Classification Chart", note the
proportkms are approximate and modifications to the soil group due to
stratification, mcluslons and changes m properties are included.
Moisture Content · tbisisaqualitative measure:
d.~y.., m~ or little apparent surface moisture,
damp, moisture forms portion of color, less than plastic limit,
wet, no free water, often soft, if cohesive soil,
saturated, free water may be squeezed out, ifa free draining soil;
dilatent at natural moisture content, if a non:plastic silt or fine
sand. (The moisture conten.t is further defined by reference t9 PI,
LW, NP, M%or dilatenc, y,)
Density refers to ~nore-or-less nou-cohesive soils, such as sand gravel
mixtures with or without a fine fraction, derived from drilling action
and/or sample data; usua!ly described as: very loose, loose, medium
dense, very den~;e. General intent is to portray earthwork
characteristics.
Stiffness - refers to more-or-less cohesive soils and fine grained silts of
~silt groups. Derived frotn drill action and/or sample data. Very
soft, soft, stiff, very stiff and }lard are commonly used terms.
Particle size -- The largest particle recovered by the split spoon is
1-3/8", Shelby tube 3", auger flight~ (minute-man) 2", Auger flights
(B-SO hollow stem) 6"-8", Larger particles are described indirectly by
action of the drilling attd are referred to as cobblea, 3" to 8", or
boulder~ 8"+, Therefore when reviewing the gradation sheets, if any,
the description on the bole log must be considered for an/indication of
larger particles,
Unified Soil Classification - This is a two letter code. See Unified
Classification sheet for further definition, In some cases AASHO aud/or
FAA soil classifications may be shown as well as the unified.
Atierberg Limits - useful for fine grained and other plastic soil~,
PI; natm'al moisture content believed to be less than plastic limit
PI+; natural moisture content believed to be between plastic and liquid
IWmit s
L_~w+; natural moisture content believed to be greater .than liquid limit
NP; non-plastic, useful as a modifying description of some silty
~aat/~tials.
Dilatency - is the ability of water to migrate to the surface of a
saturated or nearly saturated soil sample when vibrated or jolted - u~ed
as all aid to determine if a fine grained soil is a slightly or non-plastic
silt or a volcanic ash.
Rock flour -- finely ground soil that is not plastic but otherwise appears
similar to; clayey silt.
Organic Content - usually described as Peat, PT, so~netimes includes
discrete particles such as wood, coal, etc. as a modifier to .m inorganic
soil. Quantity described as', trace, or an estimate of volume, or, in case
of all organic,-- as Peat. This may include tundra, muskeg and bog
material.
Muck - a modifier used to describe very 'soft, semi-organic deposits
· usually occuring below a peat deposit.
Amorphus peat -- organic particles nearly or fully disintegrated.
Fibrous Peat - organic particles more-or less intact.
Bottom of Testhole - includes last sample intervah
Frost Line - seasonal frost depth as described by drilling action and/or
samples at the time of drilling.
Frozen Ground - other than frost line, des&ibed by samples, usually
includes description of ice content, often v/ill include modified Unified
Classification for frozen soils - this is a special case related to
permafrost studies.
Free Water Level - The free water level noted during drilling. This is
not necessarily the static water table at the time of drilling or at other
seasons, Static water table determination in other than very permeable
soils requires observation wells or piezometer installations, used only itl
special cases,
Blow/6" - The number of blows of a 140 weight free falling 30" to
advance a 2" split spoon 6"; the number of blows for a 12" advance is,
by definition, thc standard penetration,
,el% - natural moisture content of the soil sample~ usually not
p-~'rformed on clean sands or gravels below the water table.
Type of Sample -
SP, refers to 2" split spoon driven into the soil by 140 pound
weight, a disturbed sample,
S, ihin wall tube, '!Shelby" used to obtain undisturbed samples
of fine grained soil,
G,"grab" disturbed sample from auger flights or walloftrench,
C, cut sample, undisturbed sample from wall of trench.
Dry Stren[~tb - a useful indicator of a soil's clayey fraction, N=None,
L=Low, M=Medium, H=High
Gro.up - The samples are placed into apparently similar groups based
on color and texture and are arbitrarily ~tssigned a group letter. Further
disturbed tests including Atterberg Limits, grain size, moisture~ensity
relationship, etc. may be performed on the group and are assumed to
reflect the general distrubed characteristics 6f the soils assigned to the
group. This is an important phase of the soil analysis and is used to
standardize the various qualitative determinations and to reduce the
number of quantitative tests necessary to describe the soil mass.
SOIL CLASSIFICATION CHART
30% GRAVEL
CLAY
CLAYEY' CLAYEY
CLAYEY
OR
SILTY SILTY
SILTY \ ~
SAND
~ GRAVELLY SAND SANDY GRAVEL
SAND GRAVELLY SAND SANDY GRAVEL : GRAVEL
\ \
0 10 20 30 40 50 60 70 80 90 00
GRAVEL +#4 SCREEN) % BY WEIGHT
NONFROST SUSCEPTIBLE SOILS ARE INORGANIC SOILS CONTAINING LESS THAN 3% FINER THAN 0.02 mm.
GROUPS OF FROST-SUSCEPTIBLE SOILS:
F1 GRAVELLY SOILS CONTAINING BETWEEN 3 AND 20% FINER THAN 0.02 mm.
F2 SANDY SOILS CONTAINING BETWEEN 3 AND 15% FINER THAN 0.02 mm.
F3 a. GRAVELLY SOILS CONTAINING MORE THAN 20% FINER THAN 0.02 mm. AND SANDY SOILS
(EXCEPT F:INE SILTY, SANDS) CONTAINING MORE THAN 15% FINER THAN 0.02 mm.
b. CLAYS wITH PLASTICITY INDEXES OF MORE THAN 12. EXCEPT VARVED CLAYS.
F4 a. ALLSILTS INCLUDING SANDY SILTS.
b. FiNE SILTY SANDS CONTAINING MORE THAN 15% FINER THAI~ 0.02 mm.
c. LEAN CLAYS WITH PLASTICITY NDEXESOF LESS THAN 12.
d. VARVED CLAYS.
Mr. A1 Pace
4611 Business Park Blvd.
Anchorage, Alaska 99503
Subject:
4040"B" STREET
ANCHORAGE, ALASKA 99503
(907) 278-1551
October 5, 1979
W.O. #A19064
Grid # 36.3~
Additional Shallow Subsurface Investigation for Suitability
of On-Site Wastewater Disposal Systems - A 20-Acre Parcel
Near Potter Creek Within the Northeast 1/4, Section 14,
TllN, R3W, SM, Alaska
Dear Mr. Pace:
We have completed an additional shallow subsurface investigation on
the property described above which is near Potter Creek. The purpose
of this investigation was to determine the suitability of the lots in
the proposed subdivision for on-site wastewater disposal systems and
'to make a preliminary determination of shallow subsurface conditions
fcr planning purposes.
A previous investigation was conducted in March 1979 and a report
issued on M~r~h 26 197~ At that time th~ ~ee~ snow cover and
terra~:evented the drill~g of all of the_planned test borinq's~
~rn~.i~~~'~ion ~es-cs. This present investigation supplements
the work completed in ~{arch.
CONCLUSIONS
In general, our conclusions as stated in the March 26 letter remain
the same. We are of tha opinion that on--site wastewater disposal
systems can be constructed in accordance with the Municipality of
Anchorage regulations on most of the lots. The soils in the area
consist of predominately gravelly silty sands derived from glacial
till and alluvi~ma. This till is not highly permeable and thus perco-
lation rates are rather slow. Table I attached to this letter lists
recont~nended absorption trench areas. These recommendations are based
on design criteria contained in "Manual of Septic Tank Practice",
U.S. Public Health Service, Washington D.C., publication number 256.
We have been conservative in~ the absorption trench area
because the so~ls are cuite ~%~--~..~Yd could tend to l~with use~
...o=s where no percolation 'tests were conducted we have based our
recom~endations on the highest test results in nearby borings. It is
possible that a percolation tes~ in these lots could result in
shorter absorption trenches.
~Mr. A1 Pace
October 5, 1979
Page Two
As noted on Table 1, the boring on the lot line between Lots 3 and 4,
Block 1 encountered g~undwater at seven f?~ An additional hole
was drilled upslope-~~~i~-75~~nd this hole encountered
groundwater at eight feet. Based on this boring we do not recommend
that on-site wastewater disposal systems be placed on these lots
without additional information. As stated in the March report, due
to the soils and terrain, groundwater conditions can be a problem in
localized areas.
We recommend that seepage trenches be inspected prior to installing
the system. As these recommendations are based on a six-inch diameter
test hole, the seepage trench will provide a much clearer picture of
the subsurface conditions than the test hole. If conditions are
different than encountered in the borings, it may be necessary to
ify the design~
FIELD EXPLORATION AND TESTING
The exploration was conducted using a continuous flight solid stem
auger drill rig, owned and operated by Denali Drilling, Inc. The
drill was mounted on a tracked Nodwell carrier. The drilling was
supervised, the test holes logged and the percolation performed by
Mr. O. Hatch, Alaska Testlab geologist/senior field technician.
When the drilling was completed a 3/4-inch slotted PVC pipe was
inserted into the hole to aid in determining the free water level.
The test hole was then filled with water and left overnight to
saturate. On returning the next day the hole was refilled with water
~and the drop in water level carefully monitored over the next 60
minutes.
This procedure is not a standardized percolation test, however, we
understand that the Municipality of Anchorage, Department of Health
and Environmental Protection, prefers tests performed in this manner
to evaluate a site for a proposed sewage system.
The following are attached and complete this report.
Site Plan
Test Hole Logs
Explanatory Information
Grain-Size Distribution Curves
Figure 1
Tables A-D
Sheets 1-3
Sheets 4-5
.Mr. A1 Pace
October 5, 1979
Page Three
We trust this information meets your present needs.
further service please do not hesitate to contact us.
JRF/ms
Attachments
If we can be of
Very sincerely,
ALASKA TESTLAB
a~es Ri ~Fin~le~,~r., P.E.
Geotechnical Engineer
Approved by:
Laboratory Manager
TABLE 1
RECOMMENDED ABSORPTION TRENCH AREA
Block
1
3
Lot
1
2
3
4
2
Recommended*
Percolation Absorption
Applicable Rate Trench Area
Boring (min./in.) (ft.2/~ed~oom)
TH-1 23 [:~.2'25 /
TH-A- 1
TH-A- 1
TH-A- 2 4
TH-A-2 4 150
TH-A-3~ 8 150
TH-A-3~ 8 150
TH-5 13 175
TH-5 13 175
TH-4
TH-1 ,
TH- 2A
TH-2A
TH-2A,
TH-3
TH-3
TH - 3 A
200-,---"
oo-
200--L
6 TH-A- 4 20 ,. .
7 TH-A- 4 20e~s 210 ~
*Absorption trench area recommendations based on d i-g eria
contained in "Manual of Septic Tank Practic", U.S. Public Health
Service (Washington, D.C.: U.S. Government Printing Office, 1957),
PubliCation No. 256.
roundwater encountered by Test Hole A~-l~'-~e~v~e~-~-"f~et~-~epth.---~
n-site- wa_stewa_ter.~._.~.~.._..di~posal_ -.---~.__. not recommended on these lots.
system
Test Hole #A-1
Table A
WO #Al 9064
Date: 10/1/79
Logged by: O. Hatch
Depth in Feet
From To
0.0 1.0
~z~l.0 3.0
,/
~3.0 7.0
7.0 10.0
Soil Description
Brown Peat, damp, soft
F-l, brown slightly Silty Sandy Gravel, damp,
medium dense, rounded particles to 3", GM
F-4, brown Gravell~ Sandy Silt, damp, stiff,
plastic, rounded particles to 3", ML
F-2, brown Gravelly very Silty Sand, saturated,
medium dense, rounded particles to 3", SM
Bottom of Test Hole:
Frost Line:
Free Water Level:
10.0 Feet
None Observed
7.0'Feet While Drilling
Sa.
No. Depth
I 5
2 10
M% Group Unified
11.6 A ML
14.2 A SM
Remarks: 1.
e
e
4.
5.
6.
A second test hole drilled uphill 75 feet encountered
groundwater at eight feet depth.
All samples obtained by grabbing material as brought to
surface by auger.
Group refers to similar material, this study only.
General Information, see Sheet 1.
Frost and Textural Classification, see Sheet 2.
Unified Classification, see Sheet 3.
Test Hole #A-2
Table B
WO #A19064
Date: 10/1/79
Logged by: 0. Hatch
Depth in Feet
From To
0.0 1.5
1.5 16.0
Soil Description
Brown Peat, damp, soft, Pt
F-4, brown Gravelly very Silty Sand, SM
Bottom of Test Hole:
Frost Line:
Free Water Level:
16.0 Feet
None Observed
None Observed
Percolation Rate = 4 minutes/inch
Water Level at Start of Test = 5.0 Feet
Sa.
No. Depth M%
I 5 10.3
2 10 4.0
3 15 10.9
Group Unified
A SM
B SM
A SM
Remarks: 1.
3.
4.
5.
Ail samples obtained by grabbing material as brought to
surface by auger.
Group refers to similar material, this study only.
General Information, see Sheet 1.
Frost and Textural Classification, see Sheet 2.
Unified Classification, see Sheet 3.
Test Hole #A-3
Table C
WO #A19064
Date: 10/1/79
Logged by: O. Hatch
Depth in Feet
From To
0.0 1.5
1.5 16.0
Soil Description
Brown Peat, damp, soft, Pt
F-4, brown Gravelly very Silty Sand, damp,
stiff, slightly plastic, subrounded particles
to 3", grades very gravelly below 12', SM
Bottom of Test Hole:
Frost Line:
Free Water Level:
16.0 Feet
None Observed
None Observed
Water Level at Start of Test = 4.0 Feet
Sa.
No. Depth M% Group Unified
I 5 9.5 A SM
2 10 12.5 A SM
3 15 10.0 A SM
Remarks:
1. Ail samples obtained by grabbing material as brought to
surface by auger.
2. Group refers to similar material, this study only.
3. General Information, see Sheet 1.
4. Frost and Textural Classification, see Sheet 2.
5. Unified Classification, see Sheet 3.
Test Hole #A-4
Table D
WO #A19064
Date: 10/1/79
Logged by: O. Hatch
Depth in Feet
From To
0.0 I .5
1.5 16.0
Bottom of Test Hole:
Frost Line:
Free Water Level:
Soil Description
Brown Peat, damp, soft, Pt
F-4, brown Gravelly very Silty Sand, stiff to
hard, plastic, subrounded particles to 3", SM
1620 Feet
None Observed
None Observed
Percolation Rate = 20 minutes/inch
Water Level at Start of Test = 5.0 Feet
Sa.
No. Depth M%
I 5 10.5
2 10 10.8
3 15 7.3
Group Unified
A SM
B SM
A SM
Remarks: 1.
3.
4.
5.
Ail samples obtained by grabbing material as brought to
surface by auger.
Group refers to similar material, this study only.
General Information, see Sheet 1.
Frost and Textural Classification, see Sheet 2.
Unified Classification, see Sheet 3.
Test Hole Lo9 - Description Guide
The soil descriptions shown on the logs are the best estimate of the soil's
characteristics at the time of field examination and as such do not achieve the
psecision of a laboratory testing procedure. If the log includes soils samples,
those samples receive an independent textural classification in the laboratory
to verify the field examination.
The logs often include the following items:
. Depth Interval - usually shown to 0.1 foot, within that zone no
significant change in soil type was observed through drill action, disect
observation or sampling.
Frost Classification - NFS, Fl, F2, F3, F4, see "Soil Classification
Chart"
Texture of Soil - An engineering classification of the soils by particle
size and proportion, see "Soil Classification Chart", note the
proportions are approximate and modifications to the soil group due to
stratification, inclusions and chauges in properties are included.
Moisture Content .- this is a qualitative measure:
d.~, .o or little apparent surface moisture,
damp. moisture forms portion of color, less than plastic limit,
wet, no free water, ofien soft, it' cohesive soil,
saturated, free water may be squeezed out, ifa free draining soil:
dilatent at natural moisture content, if a non-plastic silt or fine
sand. (Thc moisture content is further defined by reference to PI,
LW, NP, M%or dilatency.)
Density - refers to more-or-less non<ohesive soils, such as sand gravel
mixtures with or without a fine fraction, derived from drilling action
and/or sample data: usually described as: very loose, loose, medium
dense, very dense. General intent is to portray earthwork
characteristics.
Stiffness - refers to more-or-less cohesive soils and fine grained silts of
t~ clay-silt groups. Derived from drill action and/or sample data, Very
soft, soft, stiff, very stiff and hard are commonly used terms.
Particle size - The largest particle recovered by the split spoon is
1-3/8", Shelby tube Y', auger flights (minute-man) 2", Auger flights
{13-50 hollow stem) 6"-8". Larger particles are described indisectly by
action of the drilling and arc referred to as cobbles, 3" to 8', or
boulders 8"+. Therefore wheu reviewing the gradation sheets, if any,
the description on the hole log must be considered for an:indication of
larger particles.
Unified. Soil Classification - This is a two letter code. See Unified
Classfficatiou sheet for further definition. In some cases AASHO and/or
FAA soil classifications may be shown as well as the unified.
Atserberg Limits - useful for fine grained and other plastic soils.
PI; natural moisture content believed to be less than plastic limit
P__l+; natural moisture content believed to be between plastic and liquid
limits
L__.~; natural moisture content believed to be greater than liquid limit
· NP; non-plastic, useful as a modifying description of some silty
~-dat~rials,
Dilatencv - is the ability of water to migrate to the surface of a
saturated or nearly saturated soil sample when vibrated or jolted -- used
as an aid to determine if a fine grained soil is a slightly or non-plastic
silt or a volcanic ash.
Rock flour - finely ground soil that is not plastic but otherwise appears
similar to a clayey silt.
Organic Content - usually described as Peat, PT, sometimes includes
discrete particles such as wood, coal, etc. as a modifier to an inorganic
soil. Quantity described as: trace, or an estimate of volume, or, in case
of all organic, - as Peat. This may include tundra, muskeg and bog
material.
Muck - a modifier used to describe very soft, semi-organic deposits
usually occuring below a peat deposit.
Amorphus peat - organic particles nearly or fully disintegrated.
Fibrous Peat - organic particles more-or-less intact.
Bottom of Testhole - includes last sample interval.
Frost Line - seasonal frost depth as described by drilling action and/or
.samples at the time of drilling.
Frozen Ground - other than frost line, described by samples, usually
includes description of ice content, often will include modified Unified
Classification for frozen soils - this is a special case related to
permafrost studies.
Free Water Level -- The free water level noted duriug drilling. This is
not necessarily the static water table at the time of drilling or at other
seasons. Static water table determination in other than very permeable
soils requires observation wells or piezometer installations, used only ill
special cases.
I½]ow/6" -- The number of blows of a ! 40 weight free falling 30" to
advance a 2" split spoon 6"; the number of blows for a 12" advance is,
by definition, the standard penetration.
,v~% - natural moisture content of the soil sample, usually not
p-~formed on clean sands or gravels below the water table.
Type of Sample -
S.._P, refers to 2" split spoon driven into the soil by 140 pound
weight, a disturbed sample,
~, thin wall tube, "Shelby" used to obtain undisturbed samples
of fine grained soil,
f;,, "grab" disturbed sample from auger flights or wall of trench,
~., cut sample, undisturbed sample from wall of trench.
Dry Strength - a useful indicator of a soil's clayey fraction, N=None,
L=Low,M=Medium, H=High
Group - The samples are placed into apparently similar groups based
oo color and texture and are arbitrarily assigned a group [etter. Furtller
disturbed tests including Atterberg Limits, grain size, moisture-density
relationship, etc. may be performed on the group and are assumed to
reflect the general disrcubed characteristics of the soils assigned to tile
group. This is an important phase of the soil analysis and is u~cd to
standardize the various qualitative determinations and to reduce tile
number of quantitative tests necessary to describe the soil mass.
SOIL CLASSIFICATION CHART
30% GRAVEL
CLAY
CLAYEY
or
SIltY
CLAYEY CLAYEY
SI LTY SILTY
CLAYEY
SILTY
SAND GRAVEL
GRAVELLY SAND SANDY GRAVEL\ . X/
SAND GRAVELLY SAND GRAVEL GRAVEL
/
0 10 20 30 40 50 60 70 80 90 100
GRAVEL (+#4 SCREEN) % BY WEIGHT
NONFROST SUSCEPTIBLE SOILS ARE INORGANIC SOILS CONTAINING LESS THAN 3% FINER THAN 0.02 mm,
GROUPS OF FROST-SUSCEPTIBLE SOILS;
F1 GRAVELLY SOILS CONTAINING BETWEEN 3 AND 20% FINER THAN 0.02 mm.
F2 SANDY SOILS CONTAINING BETWEEN 3 AND 15% FINER THAN 0.02 mm.
F3 a. GRAVELLY SOILS CONTAINING MORE THAN 20% FINER THAN 0,02 mm. AND SANDY SOILS
(EXCEPT FINE SILTY, SANDS) CONTAINING MORE THAN 15% FINER THAN 0.02 mm.
b. CLAYS WITH PLASTICITY INDEXES OF MORE THAN ]2. EXCEPT VARVED CLAYS.
F4 a. ALL SILTS INCLUDING SANDY SILTS.
b. FINE SILTY SANDS CONTAINING MORE THAN 15% FINER THAN 0.02 mm.
c. LEAN CLAYS WITH PLASTICITY INDEXES OF LESS THAN 12.
d. VARVEO CLAYS.
u~ a~ o~
o o o o o o
_o
0
0
o _o ~o o o c
40~4~0'~'1J ST R E ET
ANCHORAGE, ALASKA 99503.
(907) 278-1551
W.O. A18778
Grid 3639
~. A1 Pace
4611 Business Park Blvd.
Anchorage, AK 99503
Subject: ~Shallo~ Subsurface Investigation for Suitability of
On-Sit~Wastewater Disposal Systems---A 20-Acre Parcel
Near Potter Creek within the NE 1/4, Section 14,
T11N, R3W, SM, Alaska
Dear Mr. Pace:
We have completed a shallow subsurface investigation on your
20-acre parcel near Potter Creek (see Figur% 1). The purpose
of this investigation was to determine the suitability of the
designated area for on-site wastewater disposal systems and to
'm~ke a preliminary determination of the shallow subsurface
conditions for planning'purposes.
CONCLUSIONS
Based on the results of this investigation we believe the
site generally will be suitable for construction of on-site
wastewater disposal systems, in conformance with Municipality
of Anchorage regulations.
Our original exploration program included the placing of
8 to 10 test holes. However, due to the terrain and deep
snow cover, we were only able to place 5 test holes.
Additional exploration, with percolation tests, should be
conducted after the spring thaw, when access is available.
No bedrock or ground water was discovered during the
exploration, however, the site is in a general area where
bedrock and ground water can be problems. Again, these
conditions should be looked for carefully in the next phase
of exploration. In any event, rock outcroppings, natural
drainage soils, springs, etc., should be avoided when con-
structing disposal systems.
Mr. A1 Pace
March 26, 1979
Page Two
DISCUSSION
The subsurface investigation consisted of five testholes, three
percolation tests, and laboratory analysis of soil samples
obtained during the field investigation. The testholes were
drilled with a Nodwell-mounted Mobile Drill B-50 rig equipped
with a continuous flight auger, owned and'operated by Denali
Drilling, Inc. Drilling of each testhole was under the
direction of Terry Barber,.geologist/field technician, Alaska
Testlab.
To evaluate the soil conditions, ~Ir. Barber logged each hole
while drilling was in operation and.took samples directly off
the auger at varied intervals. Each sample was placed in a
sealed plastic bag to preserve its water content. In the labor-
atory, water content and dry strength were determined for each
sample. The samples were then placed in arbitrary groups
according to their color, texture, and grain size distribution.
Grain size analysis, Atterberg limits, and water content, were
then performed on the composite samples of ~hese arbitrary soil
groups. -~
Three distinct soil groups were ~ncountered. They are described
below.
GROUP A
GROUP B
GROUP C
is a brown silty gravelly sand with 'a trace of clay.
This group is very frost susceptible with a frost
classification of F-3. Its unified classification
is SM. Grain size gradations are shown on Sheet 4.
is a brown silty gravelly sand with some clay. This.
group is very frost susceptible with a frost classi-
fication of F-3. Its unified classification is SM.
Grain size gradations are shown on Sheet 5.
is a brown, poorly graded, silty, sandy gravel found
in the last several' feet of Testholes 2A, 3A, and 5.
The observed gravel had a maximum size of 1 inch.
This group is moderately frost susceptible with a
frost classification of F-l/F-3. Its unified classi-
fication is GM.
The grain size distribution curves show the range and percent by
weight of particle sizes evident in each soil' group. Larger
particles may be present in situ; however, the action of the
auger may exclude them from being sampled.
Mr. A1 Pace
March 26, 1979
Page Three
Prelimary evaluation of the area for on-site wastewater treatment
systems was performed. This evaluation was accomplished by
inserting a 3/4-inch PVC pipe in a test hole to assist in
measuring the test hole's water level. The hole was then filled
with water and left overnight. The next day the hole was refilled.
After refilling, the fall rate of the water over the next 60 minutes
was recorded. This test was conducted in Test Holes 1, 3A, and 5.
These test holes were chosen to obtain representative values
.for the percolation rates in the general investigation area.
The following percolation rates were observed using the aforementioned
procedure.
Testhole
Rate (min./inch)
1 23
3A 20
5 13
Ground water was not observed in any of the f~ve.test holes.
The following figures, tables, and. graphs complete this report:
Test Hole Location Sketch
Test Hole Logs
Standard Explanatory Information
Grain Size Distribution Curves
· Figure 1
Table A
Sheets 1-3
Sheets 4-5
We trust the above meets your present requirements. If you have
any questions or if we may be of further assistance, please do not
hesitate to contact us.
Very sincerely,
ALASKA TE STLAB
Jordan E. Jacobsen
Approved by:
Melvin R. Nichols, PE
Laboratory Manager
JEJ:gla:mm
Test Hole #1
TABLE A
WO #A18778
Date: 3/2/79
Logged by: T. Barber
Depth in Feet
From To
0 1
1 6
6 16
Soil Description
F-4, brown Peat, frozen, Pt.
F-3, brown silty gravelly Sand, wet, sharp
particles, SM,' Group A.
F-3, brown silty gravelly Sand, gravel layer
from 5' to 6', low to med. density, wet, stiff
to hard, sharp particles SM, Group B.
Bottom of Test Hole: 15 ft.
Frost Line: I ft. '~
Free Water Level: None
Type of Dry
Sample Depth Sample Strength Group
1 5
2 10
3 16
M% Unified
11.8 G L A SM
12.9 G M/H B SM
11.9 G M B SM
Remarks:
1. Type of Sample, G=Grab, SP = Standard Penetration,
U = Undisturbed.
2. Dry Strength, N=None, L=Low, M=~edium, H=High.
3. Group refers to similar material, this study only.
4. General Information, see Sheet 1.
5. Frost and Textural Classification, see Sheet 2.
6. Unified Classification, see Sheet 3.
Test Hole #2-2A
TABLE A
WO #A18778
Date: 3/1/79
Logged by: T. Barber
Depth in Fee%
From To
Soil Description
0 1.5
1.5 7
F-4, brown Peat, Pt.
F-3, brown silty gravelly Sand, wet to saturated
low to medium density, subrounded to rounded
particles SM, Group A.
7 9
Transihion zone from sand to gravel.
Remarks:
15 F1 to F3, brown silty sandy Gravel, wet to
saturated, high density, sharp to subrounded
particles, GM, Group C.
Moved from TH2 to TH 2A due to refusal at 9 ft. Drilled
2A '15 ft. West.
Bottom of Test Hole: 15 ft.
Frost Line: 1 ft.
Free Water Level: None
Type of Dry
~ample Depth M% ~ample Strength Group unified
3.5 Sat. G L/M A SM
14.9
2 9 Sat. G L~M A SM
12.9
~A
Remarks:
15
1.
2.
3.
4.
5.
6.
8.1 G L C GM
Type of Sample, G=Grab, SP = Standard Penetration,
U = Undisturbed.
Dry Strength, N=None, L=Low, M=Medium, H=High.
Group refers to similar material, this study only.
General Information, see Sheet 1.
Frost and Textural Classification, see Sheet 2.
Unified Classification, see Sheet 3.
Test Hole #3A
TABLE A
WO #A18778
Date: 3/1/79
Logged by: T. Barber
Depth in Feet
From To
0 1
I 7
7 10
10 15
Bottom of Test Hole:
Frost Line:
Soil Description
F-4, brown Peat, Pt.
F-3, brown silty gravelly Sand, damp-to wet,
high density, sharp partiCle~, SM, Group B.
F-3, brown silty gravelly Sand damp to wet,
high density, sharp particles, SM, less
gravel than interval directly above, Group B.
F-'2, brown silty sand Gravel, damp, high to
very high density, sharp particles, GM,
Group C.
15 ft.
1 ft.
Remarks: Moved from TH3 to
TH3A due to refusal at 5 ft.
Drilled TH3A 50 ft. south.
Free Water Level:
None
sample Depth
I 5
2 10
3 15
Type of Dry
M% Sample Strength Group Unified
13.1 G VL/L B SM
11.9 G M B SM
10.0 G L C GM
Remarks:
1. Type of Sample, G=Grab, SP = Standard Penetration,
U = Undisturbed.
2. Dry Strength, N=None, L=Low, M=Medium, H=High.
3. Group refers to similar material, this study only.
4. General Information, see Sheet 1.
5. Frost and Textural Classification, see Sheet 2.
6.. Unified Classification, see Sheet 3.
Test Hole
TABLE A
WO $A18778
Date: 3/1/79
Logged by: T. Barber
Depth in Feet
From To
0 1.5
1.5 5
5 16
Soil Description
F-4, brown Peat, frozen Pt.
F-3, brown silty gravelly Sand, well graded,
damp to wet, soft, high density cohesion,
SM, Group A.
F-3, brown silty gravelly Sand, wet, hard
cohesion, high density, interbedded with
gravel layers, gravel content increased
with depth, SM, Group B.
Bottom of Test Hole:
Frost Line:
Free Water Level:
16 ft.
I ft.
None ·
Sample Depth
1 5
2 10
Type of Dry
M% Sample Strength Group Unified
12.3 G VL/L A SM
15.6 G M B SM
Remarks: 1.
3.
4.
5.
6.
Type of Sample, G=Grab, SP = Standard Penetration,
U = Undisturbed.
Dry Strength, N=None, L=Low,M=.Medlum,' H=High.
Group refers to similar material, this study only.
General Information, see Sheet 1.
Frost and Textural Classification, see Sheet 2.
Unified Classification, see Sheet 3.
Test Hole #5
TABLE A
WO #A18778
Date: 3/2/79
Logged by: T. Barber
Depth in Feet
From To
0 1
I 8
8 13
13 16
Bottom of Test Hole:
Frost Line:
Free Water Level:
Soil Description
F-4, brown Peat, frozen, Pt.
F-3, brown silty gravelly Sand, fine to medium
sand, wet, medium density, sharp particles,
interval becomes more gravelly with depth,
SM, Group A.
F-3, brown silty gravelly Sand, fine to
medium sand, wet, medium density, sharp
particles, slightly more gravelly than the
above interval, SM, Group B.
F-3, brown silty Sandy Gravel, wet, medium
density, sharp particles, very hard drilling,
GM, Group C.
16 ft.
I ft.
None.
Sample Depth
1 5
2 8.5
'3 16
Remarks: 1.
3.
4.
5.
6.
Type of Dry
M% Sample. Strength Group Unified
14.6 G L A SM
14.1 G M/H B SM
11.7 G M C GM
Type of Sample, G=Grab, SP = Standard Penetration,
U = Undisturbed.
Dry Strength, N=None, L=Low, M=Medium, H=High.
Group refers to similar material, this study only.
General Information, see Sheet 1.
Frost and Textural Classification, see Sheet 2.
Unified Classification, see Sheet 3.
Test Hole Log - Description Guide
The soil descriptions shown on the logs are the best estimate of the soiPs
characteristics at the time of field examination and as such do not achieve the
precision of a laboratory testing procedure. If the log includes soils samples,
those samples receive an independent textural classification in the laboratory
to verify the field examination,
The logs often include the following items:
Depth interval - usually shown to 0.1 foot, within that zone no
significant change in soil type was observed through drill action, direct
observation or sampling.
Frost Classification - NFS, FI, F2, F3, F4, see "Soil Classification
Chart"
Texture of Soil -- An engineering classification of the soils by particle
size and proportion, see "Soil Classification Chart", note the
prop.rtions are approximate and modifications to the soil group due to
stratifica'tion, inclusions and chauges in properties are included.
Moisture eContcnt · this is a qualitative measure:
d_D~, m~ or little apparent surface moisture,
damp, moisture forms portion of color, less than plastic limit,
wet, no free water, often soft, if cohesive soil,
saturated, free water may be squeezed out, ifa free draining soil;
dilateur at natural moisture content, if a non-plastic silt or fine
sand. (The moisture content is further defined by reference to PI,
LW, NP, M% or dilatency.)
Density - refers to more-or-less non-cohesive soils, such as sand gravel
mixtures with or without a fine fraction, derived from drilling action
and/or sample data; usually described as: very loose, loose, medium
dense, very dense. General intent is to portray earthwork
characteristics.
Stiffness - refers to more-or-less cohesive soils and fine gra!ned silts of
t e~clay-silt groups. Derived from drill action and/or sample data. Very
soft, soft, stiff, very stiff and hard are commonly used terms.
Particle size - The largest particle recovered by the split spoon is
1-3/8', Shelby tube Y', auger flights (minute-man) 2", Auger flights
(B-50 hollow stem) 6'-8", Larger particles are described indirectly by
action of the drilling and are referred to as cobbles, Y' to 8", or
boulders 8"+, Therefore when reviewing the gradation sheets, if any,
the description ou the hole log must be considered for an"indication Of
larger particles.
Unified Soil Classification - This is a two letter code. See Unified
Classification sheet for further definition, In some cases AASHO and/or
FAA soil classifications may be shown as well as the unified.
Atterbcrg Limits - useful for fine grained and other plastic soils.
PI; natural moisture content believed to be less than plastic limit
PI+; natural moisture content believed to be between plastic and liquid
ITmit s
L_~.w+; natural moisture content believed to be greaser than liquid limit
NP; non-plastic, useful as a modifying description of some silty
~aat6rials.
Dilatency - is the ability of water to migrate to the surf'.ce of a
saturated or nearly saturated soil sample when vibrated or jolted - used
as an aid to determine if a fine grained soil is a sightly or non-plastic
silt or a volcanic ash.
Rock flour - finely ground soil that is not plastic but otherwise appears
similar to a clayey silt.
Organic Content - usually described as Peat, PT. sometimes includes
discrete particles such as wood, coal, etc. as a modifier to an inorganic
soil. Quantity described as; trace, or an estimate of volume, or, in case
of all organic, - as Peat. This may include tundra, muskeg and bog
material.
Muck - a modifier used to describe very soft, semi-organic deposits
usually occuring below a peat deposit.
Amorphus peat - organic particles nearly or fully disintegrated.
Fibrous Peat - org*anic particles more-or-less intact.
Bottom of Tcsthole - includes last sample interval.
Frost Line - seasonal frost depth as described by drilling action and/or
samples at the time of drilling.
Frozen Ground - other than frost line, described by samples, usually
includes de.scription of ice content, often will include tnodified Unified
Classification for frozen soils - this is a special case related to
permafrost studies.
Free Water Level - The free water level noted during drilling. This is
not necessarily the static water table at the time of drilling or at other
seasons. Static water table determination in other than very permeable
soils requires observation wells or piezometer installations, used only in
special cases.
l~,low/~'' - The number of blows of a 140 weight free failing 30" to
advance a 2" split spoon 6"; the number of blows for a 12" advance is.
by definition, the standard penetration.
M% - natural moisture content of the soil sample, usually nat
p--eT'rformed ou clean sands or gravels below the water table.
Type of Sample -
S.._P, refers to 2" split spoon driven into the soil by 140 pound
weight, a disturbed sample,
S, thin wall tube, "Shelby" used to obtain undisturbed samples
of fine grained soil,
C,, "grab" disturbed sample from auger flights or wall of trench,
g, cut sample, ,undisturbed sample from wall of trench.
Dr}, Strength - a useful indicator of a soil's clayey fraction, N=None,
L=Low, M=Medium, H=High
Group - The samples are placed into apparently similar groups based
on color and texture and are arbitrarily assigned a group letter. Further
disturbed tests including Atterberg Limits, grain size, moisture-density
relationship, etc. may be performed on the group and are assumed to
reflect the general distrubed characteristics of the soils assigned to the
group. This is an important phase of the soil analysis and is used to
standardize the various qualitative determinations and to reduce the
number of quantitative teats necessary to describe the soil mass.
SOIL CLASSIFICATION CHART
30% GRAVEL
CLAY
0 10
OR
SILTY
SAND
CLAYEY
CLAYEY CLAYEY
CLAYEY
,
SILTY SILTY
GRAVELLY SAND SANDY GRAVEL
SILTY
GRAVELLY SAND SANDY GRAVEL GRAVEL
20 30 40 50 60 70 80 90
GRAVEL (+#4 SCREEN) % BY WEIGHT
100
NONFROST SUSCEPTIBLE SOILS ARE INORGANIC SOILS CONTAINING LESS THAN 3% FINER THAN 0.02 mm.
GROUPS OF FROST-SUSCEPTIBLE SOILS:
F1 GRAVELLY SOILS CONTAINING BETWEEN 3 AND 20% FINER THAN 0.02 mm.
F2 SANDY SOILS CONTAINING BETWEEN 3 AND 15% FINER THAN 0.02 mm.
F3 a. GRAVELLY SOILS CONTAINING MORE THAN 20% FINER THAN 0.02 mm. AND SANDY SOILS
(EXCEPT FINE SILTY, SANDS) CONTAINING MORE THAN 15% FINER THAN 0.02 mm.
b. CLAYS WITH PLASTICITY INDEXES OF MORE THAN 12. EXCEPT VARVED CLAYS.
F4 a. ALL SILTS INCLUDING SANDY SILTS.
b. FINE SILTY SANDS CONTAINING MORE THAN 15% FINER THAN 0.02 mm.
c. LEAN CLAYS WITH PLASTICITY INDEXES OF LESS THAN 12.
d. VARVED CLAYS.
Oo0o~
8
,? ' :) ,L/<
SURVEYOR'S CERTIFICATE:
CERTIFICATE OF OWNERSHIP AND DEDICATION!
NOTARY'S ACKNOWLEDGEMENT
,t97
Authorized O~f icial
TRYEK
NYMAN
6HAYES
q '-or FI
~L OCK
5
SURVEYOR'S CERTIFICATE:
VICINITY MAP
CERTIFICATE OF OWNERSHIP AND DEDICATION!
NOTARY'S ACKNOWLEDGEMENT~
PLAT APPROVAL:
~rized Official
PLAT OF
POTTER HK-IGHT~
- :' 1~81-216
8
7
5
GL OCK (~
L
CERTIFICATE OF OWNERSHIP AND DEDICATION=
l(we), hereby certify thor I om (we are) the o~ner(s) of the
property described hereon. I (we) herel~ dedicote to the public
NOTARY'S ACKNOWLEDGEMENT,
Subscribed ond sworn before me this
PLAT APP.OVAL: DTi00~ 320
JUDDiV/D£~
TRACT A
$ 4 5
i
(Comp.)
7
VICINITY MAP
l
CERTIFICATE OF OWNERSHIP ~ND DEDICATION~
NOTARY'S ACKNOWLEDGEMENT:
PLAT APPROVAL:
DTI001321
V_,-HAY6S
PLAT OF
PgTT£R /4£/~/4TJ
-- 1980-74 6