HomeMy WebLinkAboutWILLIAMS ACRES S12192 Onsite File
Williams Acres
#512192
ANDERSON ENGINEERING
P.O. BOX 240773
ANCHORAGE, AK 99524
522-7773 677-7766 (FAX)
March 1, 2017
Municipality of Anchorage
Building Safety Division
On Site Water and Wastewater Program
4700 Elmore Street
Anchorage, AK 99507
Attention: Debbie Wockenfuss
Subject: Williams Acres Subdivision, Lots 1 and 2
S Case No. 12192 — Conditions to Plat
Septic System Locations
Dear Debbie:
The developer of Williams Acres Subdivision is replatting the parcel known as T12N
R3W Section 21 W2S4NW4SE4 to include a second lot near the southern boundary.
The preliminary plat has been approved and the final plat was apparently ready for
approval when it was determined that sufficient soils information had not been provided
to insure that a septic system could be placed on the new lot. We have reviewed the
plat along with the subsurface soils on the parcel and those of adjacent lots in the area.
We are confident the soils on the new lot will support the placement of an on site septic
system.
Lot 1, Williams Acres Subdivision currently houses a three bedroom single family home.
It is served by a standard septic system with a 1,000 gallon fiberglass septic tank and a
5' wide by 53' long absorption trench with a 3' effective depth. It was constructed in
1977 in sandy gravel soil (GP/GW). The soil was visually classified at 125 square feet
per bedroom at the time of construction. The septic system has operated effectively
since that time indicating the subsurface soil was correctly classified and the absorption
trench is adequately designed.
Test hole information for this lot and the surrounding lots indicate clean sandy gravel
soils without the presence of groundwater. It is logical to assume the subsurface soil on
Lot 2 is similar to that on Lot 1 and the surrounding area. We have developed the
septic system reserve area for Lot 2 based on soils with a percolation rate of 31 to 60
minutes per inch which would be the worst case scenario for a standard septic system.
A Well and Septic System Plan for the subdivision has been completed and is attached.
The topographical information is also shown on the plan in the form of ground surface
contours. A 16,000 square foot septic reserve area has been located on Lot 2 which is
Williams Acres Subdivision
February 28, 2017
Page 2
outside the radius of the proposed private well for the lot and the 100' setback from the
small stream that traverses the right of way near the south end of the lot. We have also
shown the location and alternate site for the septic system on Lot 1 and the location of
wells and septic systems on adjacent lots in the area.
Please review the attached information and advise if further documentation is necessary
to assist with approval of Williamson Acres Subdivision.
Sincerely,
Benjamin Schiller, P.E. w% 49 TN ^ 9
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Attachments
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O'MALLEY ROAD
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50 1 I
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A B B T I TRACT A o i
4 0 TRACT B2 j
30 ix
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E. 118th Ave.
30� N89'58'53-E 300.20
30' RIGHT OF WAY
5
7 DEDICATED BY THIS PLAT.
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LOT 1 ,%Well Depth — 64' I
SWL - 35'
/O Production - 8 GPM (Log) I
o (3.295 ACRES) ' Production - 5.65 GPM (Test) ',
2-23-96) I
Private I
Well
Alternate Site1 �_ T'r a e t 9
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Private Septic Area i ,
Well ' O i
• 'I SWL Well De-88- 160' i Wellte No ----'-
'\Production - 2.17 GPM (Test) 11 b ,
;6-14-03 / z
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S86'47'44• Septic Area I-'-I I
> E 300.55y, �r"
LOT 2
//i (1.048 ACRES) ,sp`� I
V16,000 SF
`° SEPTIC RESERVE AREA �/R ,— I
>
o VACANT 100' Stream Setback
Proposed l
Private
Well•
//////
2///417///7/FA/s/T goo 0o CLEO Ave.___---
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N I TR 9
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Private
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Private
W i TR 8 SIEFKER SUBDIVISION; Na +'rn,atlaa WI
Well Depth — 71" i (' ' i
SWL - 11' ; Z I 1
Production — 5 GPM (Log) , VACANT N
, Septic Area Q I �t
Septic Area ',
-Well Depth - 64' ZI
*WA 00144I i SWL - 24' ', —,
b b T R Production - 18 GPM (Log) jj >_.I
�� •••••OF aC I r Production - 7 GPM (Test) TR l� Q,
`� • •..4. 40,00
it 6-5-12) i I
�:• "*" ••• e� I Private
Wells• II
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.;;;;4411 ... °WILLIAMS ACRES SUBDIVISION S - 12192
ci• // •� of
WELL AND SEPTIC SYSTEM PLAN
41%PitiFESSOee SCALE 1 " = 100'
‘1tquuae.14
i
- F!�. l"1 X SOILS LOG
MUNICIPALITY OF ANCHORAGE
D PERCOLATION
�® i�, ,,.r DEPARTMENT OF HEALTH AND ENVIRONMENTAL PROTECTIO TEST
f, �, Pouch 6650, Anchorage,Alaska 99502 276.2221
SOILS LOG PERCOLATION TEST
i1MS c____PERFORMED FOR: 1vICP.1 11 V 1 (1 A DATE PERFORMED: 5 1-20-77
LEGAL DESCRIPTION: v {'•e"-P e tc) LII WSJ Q ' " e1-s.4 W� SI `AN i'" G _
SLOPE _- _ S
DEPTH L •F- --_— -
(FEET) S t ` I]
SL...I1 (nf'(9 Sr 1.* - --LA, I 57' p_ l
. Cs P- s/vi) _
1:,,,,...h_
,,
,,
1 q,,IN . pit..
s SANpyUEL = 1 i
1
7
o (G n ) i - -- --
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a WAS GROUND WATER L — L [,_____ .1 . ' • . •..ae�..
11 ENCOUNTo �ERE /D? IC) 1 _
12 ff
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14
t
roc�j LwG , e� - I k 13 DEPTH)T.:41-1- Pct* Reading Date Gross Net Depth to Net
Time Time Water', Drop
15
1
16
17
18
19 �
20
PERCOLATION RATE (n itfutes/inch)
nn �..+ ',142
TEST BETWEEN --- � AND— ��T � —����0�
COMMENTS /2 Y ♦ t 4 _b-_-. 4 CC�CC) Q 41
•
PERFORMED i3Y:
: tom 3/9.0,64r CERTIFIED BY:Ahk 71 /` 4J,ATE: 5-.26-77
I)1,1'/ IS1 l'll'.1V 1 Ur 17rd1f.11 ft t5.1.`1i 1 AV L1. 1J' iV11:.1'.J 1111 J Its-,AI ,`•-•J. aw,r
Poi 6-650, 99542 - 2518 T . Tudor T -I
Anchorage, Alaska •r
&./(,ISISI7 /, ii-17V) , Date performedi Ajlf''Perform^d for ���•/�//D�'' r" i ,v� .J 1. _._ _.._.
Legal Description:l 2 /3_7 L i= , �J . il D/ 4l!_ No, . -JU.V9vii/A /0/S� ,.._. _
This form reports: Soils log 1.---' Percolation test II ' tit
Depthl'
Fact •/1//2%447fX $ JL _57X/RP .--- - et SITE 4k 9
2 _ _,-.• C4'J 4vt=L 1 �- R --____; __: .. ./ "_ :11\
4 - i 94-/t/12 0257 it 1 1-, ,----, T.
G - ,j �.� 5 • Q _1
______{,
3,\ / / ) `-1 111 j , -1
,. +
E }-' 1 .500 _11
\. 6,411L----:4-/--, >/htli , 1
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12 ••
13 - 4,e---.,4-VL.:- (-- - '!J
14 (fag) i j
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was ground water encountered? /✓ If yes, at what depth? • 1 •
,,
Reading Date I Gross Time 1 Net Time Dep j to fi20 Net Drop
•
---- -,.
_____ , _____:i .
__1_ _ ___ _._____i _ 11 • _ _ i
Percolation rate minute, l
Proposed installation: Seepage Pit • • •• Drain Field •
1)(2.0th of Inl t ., Depth to bottom of pit or trench ' —
COMiMENTS: U: f= / ,g ---4. f.•-8 , '�-/ �ci _o_044Q L '11 �'-te2A7,J - z.0
1 z1c .yep ,7:--1.::_ oo '2 'P s' �t; /z if- _.5"/-4,1 u'/- L? ______
Performed By: 6.;.--- AV, . r44 ', l:ittCertified [3y �_ ANI Date: _ ..
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Municipality of Anchorage ;.•.• n. .,.•F
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Department of Health&Human Services sr; 'l
p I •1 IMAM Li xiNovisCH • r`.
825 L Street,Anchorage,AK 99502-0650 y'"c -1301 ,
SOILS LOG-PERCOLATION TEST 4• - •' • ' '!'
Performed For. I any Matz Date Performed:
Legal Description: Tract 9 Siefker Subdivision .
. '
SLOPE
North I,
1 OG/OL
2 1
SP 1 ,
31
TESTHOLE NO-1 1
4 See SitejPlan
• i
5 1
1
6 SM
•
_ I
7 40%Silt 1
South 1 i 1
8
Was Groundwater
9 Encountered? Yes S
If Yes,What Depth? 16' L 1;‘,
10 Depth to Water 0 ___. •
After Monitoring 16' P
11 Date: 6/5101 E
12 Reading Date Gross Net Depth To Net Time ne Water Drop
13 .
1 5/22101 6:25 1.125"
14 2 6:55 30 1.875" .75"
3 6:56 1" ,
15 4 7:26 30 1.69" .69"
5 7:56 30 2.3B" .69"
16 _ 6 ,
1
17 Bottom ofr
Hole •1
18
•
Pere.Rate: 44 Min/Inch Pero.Hole Diameter.8"
21 Test Run Between 5 FL and 6 FL
•
Comments: Testhole Presoaked Prior to Percolation Test. SP Layer Percolates<30 Mip.per Inch.
Design System for Lower Layer or 30 to 60 Min.per Inch.
Performed By: Mike4nderson. I.Michael E Anderson Certify That This Test Was Performed
In Accordance With All State and Municipal Guidelines In Effect On This Date: 5/24/01
1
ANDERSON ENGINEERING
P.O. BOX 240773
ANCHORAGE, AK 99524
522-7773 677-7766 (FAX)
March 2, 2017
Municipality of Anchorage
Building Safety Division
On Site Water and Wastewater Program
4700 Elmore Street
Anchorage, AK 99507
Attention: Debbie Wockenfuss
On Site Services Engineer
Subject: Proposed Williams Acres Subdivision, Lots 1 and 2
S Case No. S12192
Water Availability Study
Dear Debbie:
We have collected information on several wells in the area of the proposed Williams
Acres Subdivision to estimate the possible depths and production rates of the well to be
constructed in the future on' Lot 2. A well is currently in place on Lot 1 which will
continue to serve the house on that lot. Only one well will be required as a result of the
subdivision. No information is available on the existing well, but information from the
Municipal archives indicate it was constructed with steel casing to an unknown depth in
the summer of 1977. The well has served the house on that lot adequately since that
time.
Field investigations indicate all of the wells in the immediate area were constructed
without the presence of bedrock below the surface. All wells are cased to the bottom of
the well. In all cases the wells produce a sufficient amount of water and range from 64'
to 160' in depth. The majority of the wells are at an average depth of 70'. Static water
levels in the existing wells vary from 11' to 88'.
Williams Acres Subdivision
March 2, 2017
Page 2
WILLIAMS ACRES SUBDIVISION
WATER AVAILABILITY STUDY
WELL
LEGAL DESCRIPTION DEPTH PRODUCTION -LOG PRODUCTION -TEST
Siefker#3, Tract 9, Lot 2 64' 8 GPM 5.65 GPM
Siefker, Tract 7 64' 18 GPM 7+ GPM
Thomas L. Boyle, Block 2,
Lot 2A 71' 5 GPM
Thomas L. Boyle, Block 1,
Lot 7A 60' 2.17 GPM
It is obvious from our study that any well to be constructed in this Williams Acres
Subdivision on Lot 2 in the future will be placed to a depth of 60' to 100' and will be
cased the full depth. The production rates will be sufficient to support a five bedroom
home and can be expected to be between 3 and 5 gallons per minute. The well will not
affect the operation or output of the existing wells in the area.
Sincerely, o'roe`e�
d
49 tH* #o; •�
Benjamin Schiller, P.E. • • ;1•0 �t�
iliS*
Attachments ;; �' ••
0QeOaes �®om