HomeMy WebLinkAboutLAKE O THE HILLS EAST BLK 3 LT 1
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279-2581
1940 pOST ROAD
· ANCHORAGE. ALASKA
99501
June 19, 1974
W.O. 16757
Dickinson Oswald Walch Lee, Engineers
.800 Cordova Street
Anchorage, Alaska 99501
Attn:
Mr. Lewis Dickinson
Subject:
Seepage Pit Analysis
Lot lA, Blk 3, Lake O' The Hills Subd.
DOWL W.O. 7332
Gentlemen:
Transmitted herein are the results of the subsurface investigatio~i performed
on. the above property. Exploration consisted of one 16.5 foot testhole drilled
'~by Denali Drilling Inc., employing a Nodwell mounted, Mobile B-50 drill fitted
with an 8", hollow stem, continuous flight auger. A grab sample was taken at
1 - 2' by pulling the auger from the test hole and removing the sample from the
flights near the bit. Standard penck'ation samples were taken at 5' intervals
with a 2" O.D. split spoon sampler driven into the soil, through the hollow stem
of the auger, by the action of a 140 lb. rod-guided hammer free falling 30".
The number of blows required to drive the sampler each 6" increment are recorded
on the logs. The number of blows required to drive the sampler 12" is, by definition,
the standard penetration. The soils were visually classified in the field in accordance
with sheets 1 through 3, following the text. This field classification was verified
by visual view of samples, based on the same criteria, in the laboratory. The
drilling was supervised and the test hole was logged by T .N. Huber, geologist
of our staff. The test hole was logged as follows:
Depth in Feet
FROM TO
SOIL DESCRIPTION
0 2
F-l, Brown Silty Sandy Gravel, with occasional
Boulders, Cobbles, Damp, Medium Dense, GM
-:2 6.5
F-4, Grey to Tan Silt with few Boulders and
Cobbles, Damp, Stiff, PI-, ML '
MEMBER
DOWL Engineers k"/ Page 2 ~ f June 19, 1974
(Test Hole Log Con% .)
6.5 10
10 16.0
16.0 16.5
Bottom of_Test Hole: 16.5
Frost Line: Not Recorded
F-4, Olive to Tan. Sandy Silt, Damp, Stiff, PI-, ML
F-4, Tan Sandy Silt with Random Gravel, Damp,
Stiff, Pi+, ML
F-4, Tan Silt, Saturated, Soft, Dialatent, ML
Note:' Wet to Saturated, Pi+ and Soft Layer at 9.5
Free Water Level: None Observed - But saturated layers at 9.5 and 16.5
Sample Depth Type of Sample Blows/6"
Grab
Standard Penetration
Standard Penetration
Standard Penetration
! 1.0-2.0
2 5.0-6.5 15~14/13
3 10-11.5 8/9/11'
4 15-16.5 18/19/25
Remarks:
Test h°le located per attached sketch
Elevation: existing ground
Date of Exploration: June 18, 1974
The seepage area required per bedroom by soil type (per the Greater Anchorage
Area BoroUgh) is as follows:
Soil Type (Unified Classification)
ML
SM
SP
SW
GM
GW
Seepage Area Required
275 ft2/bedroom
250 ft2/bedroom
150 ft2/bedroom
125 ft2/bedroom
225 'ft2bedroom
85 ft2/bedroom
Soils requiring greater than 250 ft2/bedroom sre not allowed in seepage pit
area calculations (per Greater Anchorage Area Borough).
DOWL Engineers ~'~,./ Page 3 / June 19, 1974
The seepage area required at depth can be expressed as follows:
Depth Unified Soils Classification Seepage Area Required
0-2 GM 225
2-16.5 ML Not Allowable
The soils encountered in this area are not suitable to accept sewage effluent. We
suggest another location be tested befOre any water wells are located, to prevent
a possible conflict in this regard.
Enclosed are some excerpts from State and Borough ordinances which may
be of value to you. For further restrictions, particularly with reference
to location of the seepage pit, we call your attention to the Greater Anchorage
Area Borough Ordinance 28-68.
Please call if we can be of further service.
Very truly yours,
ALASKA TESTLAB
John M. Lambe
JML: mm
Enclosure
Approved:
H.~. Lee, P.E.
