HomeMy WebLinkAboutLEBARGE S12194Lebarge
512194
ANDERSON ENGINEERING
P.O. BOX 240773
ANCHORAGE, AK 99524
522-7773 677-7766 (FAX)
October 16, 2015
Municipality of Anchorage
Building Safety Division
On Site Water and Wastewater Program
4700 Elmore Street
Anchorage, AK 99507
Attention: Debbie Wockenfuss
Subject: LeBarge Subdivision, S-12194
Septic System Feasibility Study
Dear Debbie:
We recently reviewed the proposed plat for LeBarge Subdivision with the intent of
completing a subsurface soils study to identify areas suitable for the construction of on
site septic system to dispose of septic effluent to be generated from the houses
proposed for construction on the newly created lots. LeBarge Subdivision is located
near the intersection of Jerome Street and O'Malley Road. The parcel will be divided
into 4 individual lots with one of the lots currently occupied. The tract is currently
identified as BLM Lot 4 T12N R3W Section 21. The new subdivision will be known as
LeBarge Subdivision, Lots 1 through 4. Access to the new lots will be from Jerome
Street.
The ground surface of the lots slopes from the east to the west at a grade from 10% to
15% with some knolls on the parcel with slopes which exceed 25%. It also slopes from
the north to the south at varying grades with an average approximating 7%. Flatter
areas were located on all of the proposed lots for home sites and septic systems. Lot
sizes are all in excess of 40,000 square feet in surface area and sufficient space is
available for placement of wells and septic systems to meet the 100' setback
requirement.
Test holes were placed on the proposed lots between May 21 and May 22, 2015. Soil
assessment and percolation testing continued during that period. Water monitoring has
been ongoing with readings last taken on October 15, 2015. To date no water has been
noted in any of the test holes to depths of over 15'. The purpose of the test holes was to
assess the underlying soil conditions and to determine whether septic systems could be
placed on the lots to serve single-family homes. The test holes were placed to various
depths ranging from 14' to 15' with no bedrock or impermeable lenses of material
encountered. The locations of the test holes were determined in the field for use in the
future for developing septic systems. Percolation benches were constructed at various
LeBarge Subdivision
October 16, 2015
Page 2
depths in the holes, but primarily 3' to 5.5' below the original ground surface. A
percolation cavity was prepared to determine the absorptive characteristics of the soils
encountered. The cavity was presoaked in accordance with Municipal requirements
and a percolation test performed. The results of the tests are included in the attached
documentation. In every case silty sand (SW/SM) with varying degrees of silt was
encountered full depth in all test holes. The percolation rate in the SW material ranged
from 3 minutes to 4 minutes per inch. All of the soils encountered absorbed water at
rates faster than 5 minutes per inch.
All work was completed under the direction of technicians and engineers at Anderson
Engineering. The results of the percolation tests and test hole logs are included as well
as the water monitoring results. Groundwater has not been found in any of the test
holes through the high water period of October 15.
Based on our field study and water monitoring completed to date it appears all lots of
the proposed subdivision are capable of supporting an onsite septic system. Reserve
areas for Lots 2 and 3 are shown on the attached plan. Three separate absorption
trench locations are shown for Lot 4. We are certain the majority of Lot 4 is suitable for
on site septic systems, but 10' high knolls are found on the lot with slopes in excess of
25% which preclude the use of a septic reserve areas.
The absorption trenches were designed for a five bedroom home and include a 45' long
trench by 3' wide with an effective depth of 7'. The trench locations will be shown on
the plat. The following plat notes will be added:
1. Driveways, parking areas and structures shall not be constructed over
wastewater disposal areas. There shall be a maximum of five bedrooms
placed on Lot 4.
2. Alternate locations for wastewater disposal reserved areas may be used if
approved by the municipality. In which case, the locations shown hereon
shall move to the new locations and an amended plat shall be filed with the
State Recorder's Office detailing the changes.
Sincerely,
. � OF AC
� .•••.....,,qs 1,
A � 1
I0,
Michael E. Anderson, P.E. o iii tX � 0
Attachments
F p . MICHAEL E. ANDERSON W
CE -4381
/o - I r
l '. ti V
��,11;;; Sa ,�::��
LOT 4, LEBARGE SUBDIVISION
DESIGN FACTORS: SYSTEM REQUIREMENTS
Five Bedroom Home Deep Trench System
Perc. Rate: 1-5 Min./Inch 1,500 Gallon Septic Tank
Application Rate: 1.2 GPD/SF 7' Drainfield Rock
5 Bedrooms X 150 GPD/1.2 GPD/SF (Application Rate) = 625 SF Absorption Area
625 SF/14 SF/LF = 44.6 LF Trench Length
THEREFORE: Construct a 45' Long x T Wide x 7' Effective Depth Absorption Trenches at the
Location Shown. Flow Line Elevation in Trench to be 1.5' Below Original Ground Surface. Total Depth
to be 8.5' Below Existing Ground. Provide 4' Cover Over Septic Tank and 3' Cover Over Absorption
Trench. Maintain 100' Separation from Wells in the Area.
Natural
Backfill
Geotextile
Fabric
6" O 4" Perforated
PVC (Holes Down)
T0"
3'
Drainfield Rock
TYPICAL DEEP TRENCH SECTION ••...••.����
(NO SCALE) �.•p(..........�Cq 1�i
NOTE: Grade Area Over Trench to Drain Away. u;r assn a
Minimum 6' Separation From Bedrock. ..............................
Minimum 4' Separation From Groundwater. X11*
Minimum 200' Separation From Class A Well in the Area. '��" ...........
MiCHAEI E ANDERSOry
Minimum 100' Separation From Surface Water or Streams. �i„� ., No. CE -4391 r;�,
1
2
3
4
5
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7
8
9
IC
11
12
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14
15
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MUNICIPALITY OF ANCHORAGE
DEVELOPMENT SERVICES DEPARTMENT/ON-SITE WATER AND WASTEWATER PROGRAM
1,700 ELMORE ROAD, ANCHORAGE, AK 99519-6650
SOILS LOG - PERCOLATION TEST
PROJECT #:
PERFORMED FOR: Barbara Block DATE PERFORMED: 5/22/15
LEGAL DESCRIPTION: Proposed LeBaroe Subdivision
TEST HOLE # 1 SLOPE SITE PLAN
OG/01-
Loose
G/OL
Loose
a:•
Dry
,a
Silty Sand
SW/SM
e;
4
• a
BOH 49th
See Site Plan
WAS GROUNDWATER
ENCOUNTERED No
S
NET
TIME
L
IF 1'ES, WHAT DEPTH"
O
DEPTH OF WATER None
P
AFTER MONITORING:
E
WHML E. ANO RN
No. a -43n
. PROF ESSION!�
G7
DATE: 10/15/15
READING DATF
GROSS
TIME
NET
TIME
DEPTH TO
WATER
NET
DROP
1 S/22
3:00
1,38"
2
3:30
30
8.88"
7.50"
3
3:31
1.25"
4
4:01
30
8 75"
7.50"
5 1
4:02
1.13"
6
4:32
30
8.63•'
7
PER;: RATE: 4 111N.!INCH PERC. HOLE DIAMETER! 6,•
TEST RUN BETWEEN 4.0 FT. AND S.0 T.
COMMENTS Test Hole Pre Soaked Prior To Percolation Test.
TEST PERFORMED BY: WR I, MICHAEI. F. ANDFRSON, CERTIFY THAT THIS TEST WAS PERFORMED IN ACCORDANCE
WITH ALL STATE AND MUNICIPAL GUIDELINES ON THIS DATE: 7/1/2015
1
2
3
4
5
6
7
8
9
1�
I I
14
15
IE
17
18
MUNICIPALITY OF ANCHORAGE
DEVELOPMENT SERVICES DEPARTMENT/ON-SITE WATER AND WASTEWATER PROGRAM
4700 ELMORE ROAD, ANCHORAGE, AK 99519-6650
SOILS LOG - PERCOLATION TEST
PROJECT #:
PERFORMED FOR: Barbara Block DATE PERFORMED: 5/22/15
LEGAL DESCRIPTION: Proposed LeBarge Subdivision
TEST HOLE # 2 SLOPE SITE PLAN
OG/OL
Silty Sand
SW/SM
BOH
See Site Plan
WAS GROUNDWATER
ENCOUNTERED? No
S
NET
TIME
L
F YES, WHAT DEPTH?
0
DEPTH OF WATER None
P
AFTER MONITORING:
E
49th
M AEL E. ANDERSON
No. EE -4381
DATE: 10/15/15
READING DATE
GRoss
TIME
NET
TIME
DEPTH To
WATER
NET
DROP
1 5/22
41S
0.63"
2
4:45
30
8.63"
8.00"
3
4:46
O.SO"
4
S:16
30
8.50"
8.00"
5
S:17
0.50„
6
5:47
30
8.50"
8.001,
FERC RATE: 3.75 MIN./INCH PERC. HOLE DIAMETER: 6"
TEST RUN BETWEEN 4.0 FT. AND-5-0—FT.
COMMENTS: Test Hole Pre Soaked Prior To Percolation Test.
TEST PERFORMED BY: WR I, MICHAEL E. ANDERSON, CERTIFY THAT THIS TEST WAS PERFORMED IN ACCORDANCE
WITH ALL STATE AND MUNICIPAL GUIDELINES ON THIS DATE: 7/1/2015
1
2
3
4
5
6
7
8
9
IC
I I
13
14
15
IE
17
18
MUNICIPALITY OF ANCHORAGE
DEVELOPMENT SERVICES DEPARTMENT/ON-SITE WATER AND WASTEWATER PROGRAM
4700 ELMORE ROAD, ANCHORAGE, AK 99519-6650
SOILS LOG - PERCOLATION TEST
PROJECT #:
PERFORMED FOR: Barbara Block DATE PERFORMED: 5/22/15
LEGAL DESCRIPTION: Proposed LeBarOe Subdivision (Lot 2)
TEST HOLE # 3 SLOPE SITE PLAN
OG/01-
4
G/0L
a
a
a.�
Silty Sand
,q
SW/SM
es
a
4
Q /
See Site Plan
WAS GROUNDWATER
ENCOUNTERED? No
S
NET
TIME
L
F YES, WHAT DEPTH?
0
DEPTH OF WATER None
P
AFTER MONITORING:
E
•
�. L571
fir° 49th
BOH �.A .7'.::`5 .. ..........
T WHAEL E. ANKASN C
DATE: 10/15/15
READING DATE
GROSS
TIME
NET
TIME
DEPTH TO
WATER
NET
DROP
I S/22
1:22
1.13"
2
1:52
30
10.38"
9.25"
3
1:53
1.00"
4
2 23
30
10.25"
9.25"
5
2:24
1.25'
6
2:54
30
10.50"
9.25'
PERC RATE: 3.25 MIN./INCH PERC. HOLE DIAMETER: 6"
TEST RUN BETWEEN 3.0 FT. AND 4.0 FT.
COMMENTS: Test Hole Pre Soaked Prior To Percolation Test.
TEST PERFORMED BY: WR I, MICHAEL E. ANDERSON, CERTIFY THAT THIS TEST WAS PERFORMED IN ACCORDANCE
WITH ALL STATE AND MUNICIPAL GUIDELINES ON THIS DATE: 7/1/2015
2
3
4
6
7
8
9
17
18
MUNICIPALITY OF ANCHORAGE
DEVELOPMENT SERVICES DEPARTMENT/ON-SITE WATER AND WASTEWATER PROGRAM
4700 ELMORE ROAD, ANCHORAGE, AK 99519-6650
SOILS LOG - PERCOLATION TEST
PROJECT #:
PERFORMED FOR: Barbara Block DATE PERFORMED: 5/22/15
LEGAL DESCRIPTION: Proposed LeBaree Subdivision (Lot 2)
TEST HOLE # 4 SLOPE SITE PLAN
DG/01-
A
G/OL
Silty Sand
SW/SM
See Site Plan
WAS GROUNDWATER
ENCOUNTERED? No
S
GROSS
TIME
L
IF YES, WHAT DEPTHS
O
DEPTH OF WATER None
P
AFTER MONITORING:
E
BOH
ff 49th
WHAM E. ANDERSON
No. EE -1381
PROFESS
DATE: 10/15/15
READING
DATE
GROSS
TIME
NET
TIME
DEPTH TO
WATER
NET
DROP
1
5/22
1:36
2.50"
2
2:06
30
8,75'
6.25'
3
2:07
2.25'
4
237
30
8.50"
6.25'
5
1
1 238
1
2.38"
6
3:08
30
8.63"
6,25"
FERC RATE: 4.80 MIN./INCH FERC. HOLE DIAMETER: 6"
TEST RUN BETWEEN 3.5 FT. AND 4.5 FT.
COMMENTS: Test Hole Pre Soaked Prior To Percolation Test.
TEST PERFORMED BY: WR I, MICHAEL. E. ANDERSON, CERTIFY THAT THIS TEST WAS PERFORMED IN ACCORDANCE
WITH ALL STATE AND MUNICIPAL GUIDELINES ON THIS DATE: 7/1/2015
1
2
3
4
5
6
I'
13
14
15
1�
17
MUNICIPALITY OF ANCHORAGE
DEVELOPMENT SERVICES DEPARTMENT/ON-SITE WATER AND WASTEWATER PROGRAM
4700 ELMORE ROAD, ANCHORAGE, AK 99519-6650
SOILS LOG - PERCOLATION TEST
PROJECT #:
PERFORMED FOR: Barbara Block DATE PERFORMED: 5/22/15
LEGAL DESCRIPTION: Proposed LeBaroe Subdivision (Lot 3)
TEST HOLE # 5 SLOPE SITE PLAN
OG/OL
Silty Sand
SW/SM
09INK
See Site Plan
WAS GROUNDWATER
ENCOUNTERED? No
S
[AFT
TIME
L
IF YES, WHAT DEPTn9
0
DEPTH OF WATER None
P
AFTER MONITORING:
E
i c7.;• E��
49th
NCNAEL E. ANDERSON
No. EE-4mi
i f 6•; �� f'�'• Y.
.PROFESS�O�
DATE: 10/15/15
READING DATF
GROSS
TIME
[AFT
TIME
DEPTH To
WATER
NET
DROP
1 5/22
11:28
0.88"
2
11:58
30
8.00"
7.12"
3
12:00
1.00"
4
1230
30
8.13"
7.13"
5 1
1 12:31
1
1.00"
6
101
30
8.13"
7,1 "
PEFC P,.T=, 4-20 T11P../!HCL- FERC. HOLE DIAMETER: 6_
TE T RLI: rErW F 30 PT. AND 4.00T.
COMMENTS: Test Hole Pre Soaked Prior To Percolation Test.
TEST PERFORMED BY: WR I, MICHAEL E. ANDERSON, CERTIFY THAT THIS TESS WAS PERFORMED IN ACCORDANCE
WiTH ALL STATE AND r9UNICIPAL GUIDEL'NES UN THIS DATE: 7/1/2015
1
2
3
4
5
6
7
8
9
Tf
MUNICIPALITY OF ANCHORAGE
DEVELOPMENT SERVICES DEPARTMENT/ON-SITE WATER AND WASTEWATER PROGRAM
4700 ELMORE ROAD, ANCHORAGE, AK 99519-6650
SOILS LOG —PERCOLATION TEST
PROJECT #:
PERFORMED FOR: Barbara Block DATE PERFORMED: 5/22/15
LEGAL DESCRIPTION: Proposed LeBarge Subdivision (Lot 3)
TEST HOLE # 6 SLOPE SITE PLAN
OG/01-
Silty
G/0LSilty Sand
° ,' • SW/SM
,. .
:a
e�
a,.
A' A
•0
° 0�E
i GJ :
c.' ,..••
'
BOH = 3s•.' 49th
WAS GROUNDWATER
ENCOUNTERED? No 5
L
IF YES, WHAT DEPTH? O
DEPTH OF WATER None P
AFTER MONITORING: E
DATE: 10/15/15
NICNAEE E. ANDERSON
?ROSE
See Site Plan
READING DATE
GROSS
TIME
NET
TIME
DEPTH TO
WATER
NET
DROP
1 5/22
11:41
1.25"
2
12.11
30
10.75"
9.50"
3
12:12
1.25"
4
12:42
30
10.75"
9.50"
5 1
12:43
1.00"
6
113
30
10.50"
9.50"
FERC RATE:316 MIN./INCH PERC. HOLE DIAMETER: 6"
TEST RUN BETWEEN 4.0 FT. AND 50 FT
COMMENTS: Test Hole Pre Soaked Prior To Percolation Test.
TEST PERFORMED BY: WR I, MICHAEL E. ANDERSON, CERTIFY THAT THIS TEST WAS PERFORMED IN ACCORDANCE
WITH ALL STATE AND MUNICIPAL GUIDELINES ON THIS DATE- 7/1/2015
1
2
5
4
5
6
7
8
9
MUNICIPALITY OF ANCHORAGE
DEVELOPMENT SERVICES DEPARTMENT/ON-SITE WATER AND WASTEWATER PROGRAM
4700 ELMORE ROAD, ANCHORAGE, AK 99519-6650
SOILS LOG - PERCOLATION TEST
PROJECT #:
PERFORMED FOR: Barbara Block DATE PERFORMED: 5/22/15
LEGAL DESCRIPTION: Proposed LeBarge Subdivision (Lot 4)
TEST HOLE # 7 SLOPE SITE PLAN
013/01-
Silty
G/OL
BOH
Silty Sand
SW/SM
See Site Plan
WAS GROUNDWATER
GROSS
TIME
ENCOUNTERED? No
S
NET
DROP
L
IF YES, WHAT DEPTH?
0
DEPTH OF WATER None
P
AFTER MONITORING:
E
49th •..
NKNAEL E. ANDERSON
No. EE -4361
DATE: 10/15/15
READING DATE
GROSS
TIME
NET
TIME
DEPTH TO
WATER
NET
DROP
1 5/22
9:03
2.38"
2
9:33
30
10.38"
8.00"
3
9:34
2.50"
4
1004
30
10.50"
8.00"
5
10:05 1
2.25"
6
10:35
30
10.25"
8.00"
PERC RATE: 3.75 MIN./INCH FERC. HOLE DIAMETER: 6"
TEST RUN BETWEEN 3.0 FT. AND 4.0 FT,
COMMENTS: Test Hole Pre Soaked Prior To Percolation Test.
TEST PERFORMED BY: WR I, MICHAEL E. ANDERSON, CERTIFY THAT THIS TEST WAS PERFORMED IN ACCORDANCP_
WITH ALL STATE AND MUNICIPAL GUIDELINES ON THIS DATE: 7/1/2015
5
6
7
S
9
MUNICIPALITY OF ANCHORAGE
DEVELOPMENT SERVICES DEPARTMENT/ON-SITE WATER AND WASTEWATER PROGRAM
4?00 ELMORE ROAD, ANCHORAGE, AK 99519-6650
SOILS LOG - PERCOLATION TEST
PROJECT #:
PERFORMED FOR:
DATE PERFORMED: 5/22/15
LEGAL DESCRIPTION: Proposed LeBarge Subdivision (Lot 4)
TEST HOLE # B SLOPE SITE PLAN
OG/0L
Silty Sand
SW/SM
See Site Plan
WAS GROUNDWATER
ENCOUNTERED? No
S
NET
AIME
L
IF YES, 'WHAT DEPTH/
O
DEPTH OF WATER None
F
AFTER MONITORING:
E
49th
NnIAEE E. A R5
No. EE -&M1
ZROF ESSION�
DATE; 10/15/15
READINGCATS
GROss
TIME
NET
AIME
DEPTH To
WATER
NET
vROF
1 5/22
9:19
175"
2
949
30
10.001'
8.25"
3
950
1.501'
4
10 20
30
9.75"
8.25"
5
1 10.21
2.00.,
6
10 51
30
10,25"
8.25"
PERC R'PTE: 3,64 M n;./IN'_H PERS. OCLE DIAMETER: 6"
TE,si RUIN BE vEEN 4.5 F T AND 5.5 r T.
COMMENTS: Test Hole Pre Soaked Prior To Percolation Test.
TEST PERFORMED By: WR I, MICHAEL F. ANDERSON. CERTIFY THAT This TES' WAS PERFORMED IN ACCORDANCE
WITH ALL STATE AND MUNIcIPAI GUIDELINES ON THIS DATE: 7/1/2015
LOT 1
z
0
0
CD
inin
LOT 2
z
a_
HL
z
x
0
LOT 3
z
0
ztn
(n > LOT 10
La p
> m
a N
PLOT PLAN AS BUILT x SCALE 1" = 60' GRID _ 2635 __ Project No. 15-056/TH
O'MALLEY ROAD
TEST HOLE LOCATION PLANS--*'OF.A It
�:
r LIQ TH
ABSORPTION TRENCHES LOT 4:
Five Bedroom Home — 45' Long
x 3' Wide x 7' Effective Depth
SCALE 1" = 60'
MICHAEL E. ANDERSON
CE -4381
�,,�f��0 /O• : ZT - it. •fav=
ANDERSON ENGINEERING
P.O. BOX 240773
ANCHORAGE, AK 99524
522-7773 677-7766 (FAX)
October 17, 2015
Municipality of Anchorage
Building Safety Division
On Site Water and Wastewater Program
4700 Elmore Street
Anchorage, AK 99507
Attention: Debbie Wockenfuss
Subject: Proposed LeBarge Subdivision (S-12194)
Water Availability Study
Dear Debbie:
We have collected information on several wells in the area of the proposed LeBarge
Subdivision to estimate the possible depths and production rates of wells to be
constructed in the future on Lots 1 through 4. A well is currently in place on Lot 1 which
was the focal point of our study along with the wells in Lang Subdivision immediately to
the east. The wells on this subdivision are approximately 250' from the proposed wells
for this subdivision. The information obtained from these wells is indicative of the
characteristics expected of the wells proposed for LeBarge Subdivision.
Field investigations indicate all of the wells 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 170' to 190' in depth.
SCENIC HEIGHTS SUBDIVISION
WATER AVAILABILITY STUDY
LEGAL DESCRIPTION
WELL
DEPTH
PRODUCTION - LOG
PRODUCTION - TEST
Lang, Lot 1
>100'
4.9 GPM
4.9 GPM
Lan , Lot 2
187'
10 GPM
5.78 GPM
LeBarge Subdivision
October 17, 2015
Page 2
Lang, Lot 5
186'
15 GPM
- 3.87 GPM
Lang, Lot 6
184'
20 GPM
Lot 1, LeBarge
(Proposed)
177'
10 GPM
It is obvious from our study that any wells to be constructed in LeBarge Subdivision in
the future will be placed to depths of less than 200' 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 wells will not affect the operation or
output of the existing wells in the area.
Sincerely, n
z "�
Michael E. Anderson, P.E.
Attachments
0' MALLEY ROAD
\
RW \
M.M \
f xlstlnq \\
1
Well O '1 2
> r� - ur i Existinglr'
/ WeellExisting
w",,,.ir. - m w y 40I rWell
i suu orw - nr
xxn�arxx
a-' w14 P
No Conflicts This Lot ...a .'. rn"""-
— � Exisl'm \ � a.n w - rr .-mea
With Wells or Septic I sePll<
Systems
/ I No Conflicts This Lot W ��
/ I With Wells or Septic
Systems
Existing \
� YYY Sept
o
�. ------
4� o ---
l
II
O No Conflicts This Lot I I
r
Well 5
With Wells or Septic "`" I"li, _,.,- Existing
Well I I
Systems I \ ."•., .mow rew�-
/
2 4 vv i
���•OF----=
gip.•• •• S��� , ;
' LEBARGE SUBDIVISION
f _ LOTS 1 THRU 4
..* , 49TH ���to� Util Es„t
,� ----— \— — �— A SUBDIVISION OF
�;�• No Conflicts This Lot
n,ae MICHAEL E. AND •N•: � Existing
: CE -4381 ,.4 1 wal9
�gf•e:v—Zr� *;� io 1 ,�',(�. �_,o. WATER AVAILABILITY PLANd 4111,
T1 2N, R3W, SECTION 21
���S►i�% � � .-I.., SCALE 1~ = 80• LOT 4