HomeMy WebLinkAboutCAROL CREEK S12685Onsite File
Caro I Cr k
Lots
IF
Arm j
Aff
EXCELLENCE IN CIVIL ENGINEERING SINCE 1982 • SITE PLANNING • CIVIL ENGINEERING DESIGN • PROJECT MANAGEMENT
ENGINEERING, LLC PHYSICAL MAILING OFFICE WEB
615 E. 82nd Ave., Suite 101 P.O. Box 111989 907-561-6537 triadak.com
Anchorage, AK 99518 Anchorage, AK 99511
August 21st, 2024
Municipality of Anchorage
Private Development of Development Services Department
4700 Elmore Rd.
Anchorage, Alaska 99519-6050
Attention: Greg Soule, P.E., Private Development Manager
Subject: Carol Creek Subdivision, Lots 1-7 – Onsite Soils Waiver Request REV 2
Subdivision Agreement No 24-004
Greg,
Please accept this letter as a waiver request regarding the existing soils within Lots 1-7 of Carol Creek Subdivision.
More specifically, this letter intends to request a waiver from AMCR 15.65.410C relating to test holes within
reserve areas as well as groundwater monitoring.
Available Soils Information
To date, the following soils data has been collected within the project limits; Subsurface Evaluation, Carol Creek
Subdivision, HDL Consultants, LLC and Frost Class Results within Road Alignment, Northern Geotechnical
Engineering/Terra Firma Testing. This information has been submitted to MOA during the review process for
the subdivision plans.
The results of both evaluations indicate the presence of granular materials with very low silt content present
with the project boundary. HDL’s evaluation included seven test pits advanced to depths of 12 feet below grade
with no groundwater encountered. All test pits indicated gravel soils present below the surficial sandy materials.
Additionally, test results for each of the seven test pits identified perc rates below 1 min/in in all test pits
sampled. This information has been added to MOA’s standard perc test logs and attached with this request.
Note that monitoring tubes were either not installed or were destroyed/removed after testing. Included with
this letter are the soils logs for nine properties immediately north, across Mendenhall Street. Groundwater was
not encountered within any of these properties which indicates groundwater is also not a concern within the
proposed development.
Frost classification testing was completed by Northern Geotechnical Engineering along the road alignment to
confirm in situ materials for road construction. All four samples indicated gravel materials with two results
showing F1 soils and two tests showing NFS soils present.
Lot, Reserve Area & Well Location Configuration
The special limitations for the zoning of this property limit the number of lots to be developed to seven. This
results in lot configurations with areas above the minimum requirement of 43,560 square feet. Property to the
west is currently developed as a rec center which utilizes public water and sewer systems. Property directly east
is owned by AWWU and will be a future site for a water reservoir. HLB owned property to the south is zoned PLI
August 21st, 2024
Subject: Carol Creek Subdivision Lots 1-7 – Onsite Soils Assessment for Septic REV 2
Subdivision Agreement No. 24-004 Page 2 of 4
EXCELLENCE IN CIVIL ENGINEERING SINCE 1982 • SITE PLANNING • CIVIL ENGINEERING DESIGN • PROJECT MANAGEMENT
and is expected to remain undeveloped. Private property to the southwest will eventually be developed to
medium density residential housing on public water and sewer systems. Private property to the north, across
Mendenhall Street, is fully developed with residential housing utilizing well and septic systems. Based on existing
and future land uses around the project limits, standard well and septic separation distances are achievable
within the proposed lots.
Nitrates
A screenshot from MOA’s Nitrate mapper online is provided below. From the data available, all lots within the
immediate vicinity of the subject property have reported readings below the acceptable limit of 10mg/l. Most
of the readings are below 5mg/l. Based on this information, nitrate levels from the surrounding developed
properties are not a concern as it relates to the proposed lots.
Screenshot MOA’s Nitrate Mapper (8.6.24)
Existing Well Production
The above nitrate mapper was used to analyze well production for 12 lots in the immediate vicinity of the project.
A summary of those results are attached to this letter and indicates an average well production of approximately
4.6 gpm which is above the minimum recommended production rate of 1 gpm. Static water levels reported
varied between 46 feet and 203 feet below grade. The average depth is approximately 102 feet below grade.
Based on the available data, well production is not a concern for the future development of the lots.
August 21st, 2024
Subject: Carol Creek Subdivision Lots 1-7 – Onsite Soils Assessment for Septic REV 2
Subdivision Agreement No. 24-004 Page 3 of 4
EXCELLENCE IN CIVIL ENGINEERING SINCE 1982 • SITE PLANNING • CIVIL ENGINEERING DESIGN • PROJECT MANAGEMENT
Summary
Based on the existing ownership and future development plans of the surrounding properties, separation
distances from neighboring wells and septic systems will be achievable by the Carol Creek development. Existing
nitrate levels and well production rates do not create any concern for anticipated well production within the
project limits. Additionally, soils test results indicate subsurface materials that will support absorption fields
planned within the subdivision.
Thank you for your time and consideration in this matter. If you require additional information, please call me
at (907) 344-3114 or email me at brandonmarcott@triadak.com.
Sincerely,
Triad Engineering, LLC
Brandon Marcott, P.E.
Attachments: MOA Soils Logs – Percolation Tests (TP1 – TP7)
Ex Well Production Rates Summary Table
Neighboring Soils Logs
E
N
G
I
N
E
E
R
I
N
G
,
L
L
C
BR
A
N
D
O
N
J
.
M
A
R
C
O
T
T
CE
1
2
6
0
1
R E GISTERED
PROFES
S
I
O
N
A
L
E
N
G
INEER
Depth
(Feet)
1-
2-
3-
4-
5-
6-
7-
8-
9-
10-
11-
12-
13-
14-
19-
20-
FT AND FT
(ENGINEER'S SEAL)
Performed For:
Legal Description:
15-
16-
PERC HOLE DIAMETER
Date Gross Time
Slope Site Plan
PERCOLATION RATE (minutes/inch)
Net Time Depth to Water Net DropReading
COMMENTS
TEST RUN BETWEEN
17-
18-
PERFORMED IN ACCORDANCE WITH ALL STATE AND MUNICIPAL GUIDELINES IN EFFECT ON THIS DATE. DATE:
CERTIFY THAT THIS TEST WASPERFORMED BY: HDL Engineering NA
(907)343-7904
Soils Log - Percolation Test
WAS GROUND WATER
ENCOUNTERED?
IF YES, AT WHAT DEPTH?
S
L
O
P
E
Date:
Depth to Water After
Monitoring?
Date Performed:
Township, Range, Section NW0453
Municipality of Anchorage
Development Services Department
On-Site Water and Wastewater Section
4700 Elmore St.
P.O. Box 196650 Anchorage, AK 99519-6650
www.muni.org/onsite
Criag Hanson
Carol Creek, Lots 1-7
07/07/2021
07/07/2021
4 inches
3 12
TP-1
<1
1 07/07/2021
2
3
4
5
6
07/07/2021
07/07/2021
07/07/2021
07/07/2021
07/07/2021
poorly- graded sand, (sm)
poorly graded gravel (gm)
poorly graded gravel (gp-gm)
PER HDL ENGINEERING LLC TEST
6"
6"
6"
6"
6"
6"
1.63
1.65
1.65
1.68
1.67
1.65
No
NA
Depth
(Feet)
1-
2-
3-
4-
5-
6-
7-
8-
9-
10-
11-
12-
13-
14-
19-
20-
FT AND FT
(ENGINEER'S SEAL)
Performed For:
Legal Description:
15-
16-
PERC HOLE DIAMETER
Date Gross Time
Slope Site Plan
PERCOLATION RATE (minutes/inch)
Net Time Depth to Water Net DropReading
COMMENTS
TEST RUN BETWEEN
17-
18-
PERFORMED IN ACCORDANCE WITH ALL STATE AND MUNICIPAL GUIDELINES IN EFFECT ON THIS DATE. DATE:
CERTIFY THAT THIS TEST WASPERFORMED BY: HDL Engineering NA
(907)343-7904
Soils Log - Percolation Test
Township, Range, Section:
WAS GROUND WATER
ENCOUNTERED?
IF YES, AT WHAT DEPTH?
S
L
O
P
E
Date:
Depth to Water After
Monitoring?
Date Performed:
Municipality of Anchorage
Development Services Department
On-Site Water and Wastewater Section
4700 Elmore St.
P.O. Box 196650 Anchorage, AK 99519-6650
www.muni.org/onsite
Craig Hanson 07/07/2021
Carol Creek, Lots 1-7 NW0453
TP-2
<1
1
2
3
4
5
6
07/07/2021
07/07/2021
07/07/2021
07/07/2021
07/07/2021
07/07/2021
1.03
1.03
1.00
1.02
1.03
1.07
07/07/2021
6"
6"
6"
6"
6"
6"
3 12
4"
PER HDL ENGINEERING TEST RESULTS
poorly graded sand (sm)
poorly graded gravel (gp-gm)
'
No
NA
'HSWK
)HHW
)7 $1')7
(1*,1((5
66($/
3HUIRUPHG)RU
/HJDO'HVFULSWLRQ
3(5&+2/(',$0(7(5
'DWH *URVV7LPH
6ORSH 6LWH3ODQ
3(5&2/$7,215$7( PLQXWHVLQFK
1HW7LPH 'HSWKWR:DWHU 1HW'URS5HDGLQJ
&200(176
7(67581%(7:((1
3(5)250(',1$&&25'$1&(:,7+$//67$7($1'081,&,3$/*8,'(/,1(6,1())(&7217+,6'$7( '$7(
&(57,)<7+$77+,67(67:$63(5)250('%< HDL Engineering NA
6RLOV/RJ3HUFRODWLRQ7HVW
7RZQVKLS5DQJH6HFWLRQ
:$6*5281':$7(5
(1&2817(5('"
,)<(6$7:+$7'(37+"
6
/
2
3
(
'DWH
'HSWKWR:DWHU$IWHU
0RQLWRULQJ"
'DWH3HUIRUPHG
0XQLFLSDOLW\RI$QFKRUDJH
'HYHORSPHQW6HUYLFHV'HSDUWPHQW
2Q6LWH:DWHUDQG:DVWHZDWHU6HFWLRQ
(OPRUH6W
32%R[ $QFKRUDJH$.
ZZZPXQLRUJRQVLWH
Criag Hanson
&DURO&UHHN/RWVNW0453
733
1
2
3
4
5
6
07/07/2021
07/07/2021
07/07/2021
07/07/2021
07/07/2021
07/07/2021
3.53
3.87
3.67
3.90
3.78
3.67
07/07/2021
6"
6"
6"
6"
6"
6"
312
4"
PER HDL ENGINEERING TEST RESULTS
poorly graded sand (sm)
poorly graded gravel (gp-gm)
3.7207/07/20217 6"
poorly graded sand (sm)
No
NA
'HSWK
)HHW
)7 $1')7
(1*,1((5
66($/
3HUIRUPHG)RU
/HJDO'HVFULSWLRQ
3(5&+2/(',$0(7(5
'DWH *URVV7LPH
6ORSH 6LWH3ODQ
3(5&2/$7,215$7( PLQXWHVLQFK
1HW7LPH 'HSWKWR:DWHU 1HW'URS5HDGLQJ
&200(176
7(67581%(7:((1
3(5)250(',1$&&25'$1&(:,7+$//67$7($1'081,&,3$/*8,'(/,1(6,1())(&7217+,6'$7( '$7(
&(57,)<7+$77+,67(67:$63(5)250('%< HDL Engineering NA
6RLOV/RJ3HUFRODWLRQ7HVW
7RZQVKLS5DQJH6HFWLRQ
:$6*5281':$7(5
(1&2817(5('"
,)<(6$7:+$7'(37+"
6
/
2
3
(
'DWH
'HSWKWR:DWHU$IWHU
0RQLWRULQJ"
'DWH3HUIRUPHG
0XQLFLSDOLW\RI$QFKRUDJH
'HYHORSPHQW6HUYLFHV'HSDUWPHQW
2Q6LWH:DWHUDQG:DVWHZDWHU6HFWLRQ
(OPRUH6W
32%R[ $QFKRUDJH$.
ZZZPXQLRUJRQVLWH
&ULDJ+DQVRQ
&DURO&UHHN/RWVNW0453
734
1
2
3
4
5
6
07/07/2021
07/07/2021
07/07/2021
07/07/2021
07/07/2021
07/07/2021
0.73
0.73
0.73
0.73
0.75
0.2
07/07/2021
6"
6"
6"
6"
6"
6"
312
4"
PER HDL ENGINEERING TEST RESULTS
poorly graded sand (sm)
poorly graded gravel (gp-gm)
No
NA
'HSWK
)HHW
)7 $1')7
(1*,1((5
66($/
3HUIRUPHG)RU
/HJDO'HVFULSWLRQ
3(5&+2/(',$0(7(5
'DWH *URVV7LPH
6ORSH 6LWH3ODQ
3(5&2/$7,215$7( PLQXWHVLQFK
1HW7LPH 'HSWKWR:DWHU 1HW'URS5HDGLQJ
&200(176
7(67581%(7:((1
3(5)250(',1$&&25'$1&(:,7+$//67$7($1'081,&,3$/*8,'(/,1(6,1())(&7217+,6'$7( '$7(
&(57,)<7+$77+,67(67:$63(5)250('%< HDL Engineering NA
6RLOV/RJ3HUFRODWLRQ7HVW
7RZQVKLS5DQJH6HFWLRQ
:$6*5281':$7(5
(1&2817(5('"
,)<(6$7:+$7'(37+"
6
/
2
3
(
'DWH
'HSWKWR:DWHU$IWHU
0RQLWRULQJ"
'DWH3HUIRUPHG
0XQLFLSDOLW\RI$QFKRUDJH
'HYHORSPHQW6HUYLFHV'HSDUWPHQW
2Q6LWH:DWHUDQG:DVWHZDWHU6HFWLRQ
(OPRUH6W
32%R[ $QFKRUDJH$.
ZZZPXQLRUJRQVLWH
&ULDJ+DQVRQ
&DURO&UHHN/RWVNW0453
1R
1$
735
1
2
3
4
5
6
07/07/2021
07/07/2021
07/07/2021
07/07/2021
07/07/2021
07/07/2021
1.47
1.30
1.33
1.30
1.37
1.32
07/07/2021
6"
6"
6"
6"
6"
6"
312
4"
PER HDL ENGINEERING TEST RESULTS
poorly graded sand (sm)
poorly graded sand (sm)
no water final depth of 12'
poorly graded gravel (gm)
'HSWK
)HHW
)7 $1')7
(1*,1((5
66($/
3HUIRUPHG)RU
/HJDO'HVFULSWLRQ
3(5&+2/(',$0(7(5
'DWH *URVV7LPH
6ORSH 6LWH3ODQ
3(5&2/$7,215$7( PLQXWHVLQFK
1HW7LPH 'HSWKWR:DWHU 1HW'URS5HDGLQJ
&200(176
7(67581%(7:((1
3(5)250(',1$&&25'$1&(:,7+$//67$7($1'081,&,3$/*8,'(/,1(6,1())(&7217+,6'$7( '$7(
&(57,)<7+$77+,67(67:$63(5)250('%< HDL Engineering NA
6RLOV/RJ3HUFRODWLRQ7HVW
7RZQVKLS5DQJH6HFWLRQ
:$6*5281':$7(5
(1&2817(5('"
,)<(6$7:+$7'(37+"
6
/
2
3
(
'DWH
'HSWKWR:DWHU$IWHU
0RQLWRULQJ"
'DWH3HUIRUPHG
0XQLFLSDOLW\RI$QFKRUDJH
'HYHORSPHQW6HUYLFHV'HSDUWPHQW
2Q6LWH:DWHUDQG:DVWHZDWHU6HFWLRQ
(OPRUH6W
32%R[ $QFKRUDJH$.
ZZZPXQLRUJRQVLWH
&ULDJ+DQVRQ
&DURO&UHHN/RWVNW0453
736
1
2
3
4
5
6
07/07/2021
07/07/2021
07/07/2021
07/07/2021
07/07/2021
07/07/2021
0.43
0.45
0.38
0.38
0.40
0.38
07/07/2021
6"
6"
6"
6"
6"
6"
312
4"
PER HDL ENGINEERING TEST RESULTS
poorly graded sand (sm)
poorly graded gravel (gm)
0.43 6"07/07/20217
poorly graded gravel (gp-gm)
No
NA
'HSWK
)HHW
)7 $1')7
(1*,1((5
66($/
3HUIRUPHG)RU
/HJDO'HVFULSWLRQ
3(5&+2/(',$0(7(5
'DWH *URVV7LPH
6ORSH 6LWH3ODQ
3(5&2/$7,215$7( PLQXWHVLQFK
1HW7LPH 'HSWKWR:DWHU 1HW'URS5HDGLQJ
&200(176
7(67581%(7:((1
3(5)250(',1$&&25'$1&(:,7+$//67$7($1'081,&,3$/*8,'(/,1(6,1())(&7217+,6'$7( '$7(
&(57,)<7+$77+,67(67:$63(5)250('%< HDL Engineering NA
6RLOV/RJ3HUFRODWLRQ7HVW
7RZQVKLS5DQJH6HFWLRQ
:$6*5281':$7(5
(1&2817(5('"
,)<(6$7:+$7'(37+"
6
/
2
3
(
'DWH
'HSWKWR:DWHU$IWHU
0RQLWRULQJ"
'DWH3HUIRUPHG
0XQLFLSDOLW\RI$QFKRUDJH
'HYHORSPHQW6HUYLFHV'HSDUWPHQW
2Q6LWH:DWHUDQG:DVWHZDWHU6HFWLRQ
(OPRUH6W
32%R[ $QFKRUDJH$.
ZZZPXQLRUJRQVLWH
&ULDJ+DQVRQ
&DURO&UHHN/RWVNW0453
737
1
2
3
4
5
6
07/07/2021
07/07/2021
07/07/2021
07/07/2021
07/07/2021
07/07/2021
2.18
2.23
2.32
2.33
2.38
2.40
07/07/2021
6"
6"
6"
6"
6"
6"
312
4"
PER HDL ENGINEERING TEST RESULTS
poorly graded sand (sm)
poorly graded gravel (gm)
2.37 6"07/07/20217
poorly graded gravel (gp-gm) No
NA
PROJECT: CAROL CREEK LOTS 1-7
GRADING, STREET & STORM IMPROVEMENTS
SUBDIVISION AGREEMENT NUMBER 24-004
WELL PRODUCTION RATES:
Count Well Production rates(GPM)
1
2
3
4
5
6
7
8
9
10
11
12
NOTE: DATA EXTRACTED FROM MOA MAPS FOR NITRTAE
Well Drilled Date Well Depth Static Water Level Parcel ID
7/31/1993 120.00' 2.00 96.00 5135130000
5135102000
Not provided Not provided 4.00 165.00 5135103000
Not provided Not provided 4.00 174.00
3/15/1970 92.00 7.00 82.00 5136109000
Not provided Not provided 4.00 105.00 5136132000
Not provided Not provided 3.00 65.00 5136123000
Not provided Not provided 3.00 64.00 5136123000
8/12/2003 90.00 3.00 46.00 5136125000
10/12/1997 101.00 8.00 62.00 5136124000
Not provided Not provided 6.00 203.00 5136105000
Not provided 78.00 6.00 68.00 5136110000
12/31/1972 Not provided 5.00 90.00 5135129000
