HomeMy WebLinkAboutT15N R1W SEC 5 Lot 118 S5629
~ MUNICIPALITY OF ANCHORAGE
DEPARTMEN~ OF HEALTH & ENVIRONMENTAL PROTECTION
ENVIRONMENTAL HEALTH CASE REVIEW WORK SHEET
[~ PLATTING BOARD FJ PLANNING & ZONING
ASE NUMBER NAME
S-5629 T15N R1W Section 5 Subdivision of LoC 118
DATI: RECEIVED
April 1, 1981
COMMENT TO PLANNING BY
April 13, 1981
FOR MEETING OF ' CASE OF
(I. ~"?'J'l'!, .,, ,
I~"~'-PUB LIC WATER NOT AVAILABLE TO PETITION AR EA
I~/~..PUBLIC SEWER NO~ AV,~ILABLE TO PETITION AREA
71-014 (Rev. 2/78)
SUB-SURFACE SOILS AND CONDITIONS
The surface soils found in this area is a good thickness of topsoil
overburden material.i It is a ligh~ Colored loam which would seem to
me to, be lacking as q good plant growing material. The thickness seems
to be quite uniform ~hroughout the entire area.
Below the loam for,about 2 to three feet there seems to be a difference
in the layering of thle silty materials, which wpuld show the~influence
of Peter~ Creek at once time in the near geological past. (Maturity Young)
Below this eratic layering of silts and sands and gravelly sands there
is a very dominant layer of sandy bouldery gravel with some small layering
of silts expected as !a result.of erosion sedimentation. This layer
is quite loosely packed and would allow water to percolate quite freely.
I would suspect that.this layer of rocks would extend to Peters Creek,
for a very good underground runoff condition. (This was reported by the
person that ran the blackhoe. He has has extensive experience in digging
of septic systems in ithis specific area.)
Below the rocky material is a very hard packed Bootlegger Cove Blue
Clay hardpan mixture.~ with .some rocks and cobbles mixed in to make it '
even harder. I wouldI expect no percolation thru this 'layer. The back-
hoe operator stated that this was the same as he has encountered through-
out the entire area. The depth ~is about the same over the entire basin.
He didn't seem to kno~ the thickness of this layer, not did we dig deep
enough to find out. We did dig deep enough to find that it was too deep
to consider placeing ithe septic deeper '~an 15.0 feet.
There would normally ~e some seepage alpng this inpervious layer of
clay, especially wher~ there might be ~n indentation in the clay forming
a pocket for water toI accumulate. Th~ drainage seemed to be quite
complete in the upperI layers and the hole was quite dry.
/
CONCLUSIONS
Within the layer from 4.5 to 9.0 feet from the surface there seems to -
be a very good layer!of sandy'bouldery gravelly material that would
have unlimited perco!ation and seems to be quite consistant throughout
the entire area.and ~specially over this lot.
These soils can be classified as GW . These holes'displaz spetific
conditions encountered at the test hole.locations, however sub-surface
conditions change slightly throughtout the project area.because of the
indescriminate riverlbed deposit of the river.
Bedrock was not encountered nor would it be expected in this area. At
the time the holes were dug there was no frost, no permafrost was
encountered and very ilittle water was encountered.
Based on the information obtained in these holes, it is felt that this
subdivision is suitable for single family units. ! really don't believe
that speci'al drain fields would have to be constructed, but that the
boulderymaterial would act as a good drain field in itself. The
depth of the septic system would be hampered by the impervious layer
at 9.0 feet, but theqaterial flow would be more than enough.
It is felt that the Soils conditions encountered do not preclude the
utilization of septic tanks and soils absorption systems for residential
sewerage disposal. ~
Further percolation tests are not warranted at this time not should they
be required in the fdture. /
, /
James K. Dov/ling, P.E.
^nchorage, ^laska 99501
du~ne 1, 1981
~gelo
L 05 OF TEST BOHING
Hole No.
' DOWL'ING.~'JOHN'S ' '" Sheet ~" of '- ~'
'~nglneers -- Surveyor~ .... ~ De~th ~ ~
~'11' DE$C£1PTION L~iagram: . .~ 8j~ . , ', :" <."
:--amp'-ng Local/on Notes ~ · . . ..'
--' ' " ~ ~llmoted port/cie
~ ~ ~, ~ ,~i,,~,/,/,~,o~,,, "" ' '" "' · """'' '~" ·
· } <~,,~ ~,.~,/~,/o,/o~,, .:':~'~... na~:;, .'...::: ." '~..~,:]~:: ..;,~:.~
~ ~~~}' ~ ~ ~.~ ~ ~~o~,,o,, . · ......
..... w ' ' ' '~ ' ~ o~ ~ "' ~- " : ': " ~" ..... "
~ .'<: ~ . ·
.... ,, '- ~ ~.~ /.~ +, z'~
..... .~. .. . ~~~
.-. ~ ~ -- ..
4
· ' ,~ · . ~ : . : :. · .
- ~ ~;" q ~ .y~,~,, · ~.~ t~'~,~ ~ ~.1: ...... ......,.
' ' / >' / I' '. "~'.~. '."":
.-~'-~.':~ · (:.,~';.[.<' -': ~ '.~.'~z:-x'..'.,'<:-'~:'<'~--.-~ ':'-~+':,": ~,..'"'
.... .__ q~. . ....~ . .,~ .. ~.........
--a~ -.
.... .].~-~.,' . , .. ... .
. ::z_~.,o'.: ~¢~ -- , , . , .... .-., .
--- , .... II' . --.... ...... . ..
.- _,~ ~ .~ ~ ,~
'I ', ' /'"' .....
~ .~: . , . . _.- .
.......·
-~ _. ."~ · · ..., .~ . .... . · . ~ _
- LOG OF TEST I~O~ING
un. ' _ Hole N~ ~
"0~ Comml~d /~ '~/_ ""'.,.' DOWU'I'NG';JOH~'S z":.,'.'~ sheet ~
Rig fl~ ~ . . E~gl'~eor$ -- Surve/ors ..... Total Depth
/
Table
'Sampling . · DESCRIPTION £ooal/on No/os '~ Diagram:
_ . . . soil a, pe, ¢o/o~,/o~/~,e, _e~'~ ,:,..~:.,.:::~::~:.. :......:,.>,.:.::.>'. :-:~
~ ~llmoled p~rticle ~xa~ ~ ......
s~mple~ drlvl~ not~s~ ~ ~ . .....
~ ~ ~. ~,,~/,~/~,o0/o,,, . . ~ .... .~..:. .~., ......
.~_.~ ~ ~ ~.~ ~ .. ...., . ~ ...... ~..,..... ..
~ ; ~ ~ no/es on drillin~ e~se~
~ ~ ~ ~ ~ ~. ~ ~ VogOtaMon.'~.¢~ ~': ~ ' ~ ~' ~. .~.:.... ~.}:;,. %;.:.. ~,- . ....,;; .~ ~"' .... ... :, ..,.~..:,:, .:'""':'"''-:
...... ~ ,. · . ': :~ ,,
~ ~¢ ~ ,....-: ...........,.: .
.... .. ~ ' ,.. ...
.. .. .,.... ..: :..
- ~ ;~ H~ ~" ' -~"
· -.' '. ..... ;' E~ ~:~9 ~:"-
.... ,. ., ~%~.~ ~ ,~ ~f~¢: · ~. /:~,~.','
.... ' ~: ~ ~1.~ ~1~... ......... '.: '- '.'-
· , ~ I0 · .... ~ ' ' '
.... _ _. _ ~_ ' ,..~ . ... ....'~,,' ... .... , .., ..........
'"' ~ · .... ~'~f' 'dZ~I¢_~ d¢~,~ [ ~,f "-
~_. ~ .... ~/~,~ ~ ~'. ~, : , ~ ~ ...... .,~ . · ..
~_ _/~. ~ -- , , .
--- I I~- / , .... . .
--/~ ~ .... .~ , ... >, .~,. . : .'- , ' ·