HomeMy WebLinkAboutPALATERRA ADDN 2 S12607Onsite File
1
On-site Well & Septic Feasibility NGE-TFT Project #5969-21
Proposed Lots 1-11, Palaterra Subd. – Anchorage, AK
Colony Builders, Inc.
August 10, 2021
Page 1 of 2
11301 Olive Lane Anchorage, Alaska 99515 ∙ Phone: (907) 344-5934 ∙ Fax: (907) 344-5993 ∙ Website: www.nge-tft.com
August 10, 2021 NGE-TFT Project 5969-21
Colony Builders, Inc.
9420 Vanguard Drive
Anchorage, AK 99507
Attn: Bill Taylor - Owner
RE: ON-SITE WELL AND SEPTIC FEASIBILITY OF PROPOSED LOTS 1-11 OF THE
PALATERRA SUBDIVISION - ANCHORAGE, ALASKA
Bill,
We have prepared this letter in response to comments issued by the Municipality of Anchorage
(MOA) Onsite Water & Wastewater Department on Wednesday, August 4th, 2021 requiring an
engineer’s assessment of the capabilities of proposed Lots 1-11 to each adequately dispose of
domestic wastewater and provide adequate drinking water (via drilled domestic water wells) for
each of the planned single-family residences which are to be constructed at the project site as part
of the planned subdivision development (in support of final plat approval for the proposed
subdivision).
The percolation testing that we conducted at the project site in June 2021 (as we detail in our June
2021 geotechnical report titled Geotechnical Engineering Report for Proposed Lots 1-11 of the
Palaterra, Subdivision – Anchorage, Alaska, suggests that there exist suitable soils on each of the
11 proposed lots capable of transmitting wastewater discharge at rates ranging from approximately
1 to 120 minutes per inch. Furthermore, we did not observe any indications of shallow
groundwater on any of the 11 proposed lots which could negatively affect wastewater system
design/performance. Our percolation testing program did suggest, however, that the soils on
proposed Lots 1, 6, and 7 exhibit percolation rates ranging between 80 to 120 minutes per inch.
As such, these three lots will likely require advanced wastewater treatment systems as per MOA
code. Our percolation testing also suggests that the remaining proposed lots all have soils (at some
depth shallower than 15 to 20 feet below the existing ground surface (bgs) which exhibit
percolation rates less than 60 minutes per inch and should be capable of supporting conventional
wastewater treatment systems. Individual wastewater system design will be guided by the size
and location of each proposed residence.
We did not drill/install any exploratory water wells at the project site as part of our geotechnical
subsurface exploration effort, nor are we familiar with any existing water wells on-site. However,
we reviewed publicly-available well logs for existing domestic water wells on 15 adjacent
properties surrounding the project site which indicate that viable groundwater resources exist
within saturated sand and gravel deposits at depths ranging between approximately 100 to 360 feet
On-site Well & Septic Feasibility NGE-TFT Project #5969-21
Proposed Lots 1-11, Palaterra Subd. – Anchorage, AK
Colony Builders, Inc.
August 10, 2021
Page 2 of 2
11301 Olive Lane Anchorage, Alaska 99515 ∙ Phone: (907) 344-5934 ∙ Fax: (907) 344-5993 ∙ Website: www.nge-tft.com
bgs, static water levels ranging from approximately 10 to 250 feet bgs, sustainable well pumping
rates ranging from approximately one gallon per minute (gpm) up to 10 gpm, and average water
nitrate levels less than approximately 3 mg/l. We expect similar well depths, static water levels,
production rates, and water nitrate levels to exist on-site on each of the 11 individual lots. However,
due to the variability in the existing well depths, it is difficult to predict how deep a given well will
need to be drilled on a given lot in order to tap a viable groundwater compartment (i.e., aquifer).
Given the wide range of well depths on surrounding properties it is likely that there are several
different viable groundwater compartments beneath the project site, and it remains uncertain as to
if they are interconnected or how laterally extensive they may be. An aquifer test (i.e., well pump
test) would be required in order to help evaluate the ultimate availability of any drinking water
resources and radius of influence of any well pumping on site. However, given that there appears
to be sufficient drinking water resources on adjacent properties, it is our professional opinion that
an aquifer test would be an unnecessary effort/expense.
Please do not hesitate to contact us directly with any questions or comments that you may have
regarding the information that we detail in this letter or if you have any additional questions or
comments or need any additional engineering support.
Sincerely,
Northern Geotechnical Engineering, Inc. d.b.a. Terra Firma Testing
Andrew C. Smith, CPG Keith F. Mobley, P.E.
Senior Geologist President
Legal Description Well Depth
(Feet)Well Production Static Water
Level (Feet)
Mountain Park Estates #2 L12 B3 250 8 gpm 1976, 5 gpm 2009 180
Mountain Park Estates #2 L12 B2 221 10 gpm 1977, 6 gpm 2019 179
Mountain Park Estates #2 L13 B3 Unk 3 gpm 2011 193
Spanish Hills Subd L8 255 5 gpm 1977, 3 gpm 2012 236
Spanish Hills Subd L7 340 20 gpm 1977, 4 gpm 2012 238
Spanish Hills Subd L6 358 4 gpm 2020 229
Spanish Hills Subd L5 324 10 gpm 2019 247
Spanish Hills Subd L4 126 1 gpm 1999 11
Spanish Hills Subd L3 Unk 1 gpm 2010 86
Spanish Hills Subd L1 Unk 1 gpm 2015 197
Palaterra B1 Unk 1 gpm 2011 193
Collier Subd L4 Unk 2 gpm 2014 142
Collier Subd L1 Unk 2 gpm 1999 161
Lamb Sub L3 150 9 gpm 1979 Unk
Rabbit Creek #2 TR1 104 1 gpm 2018 55
Nitrates (mg/l)
1.20
2.11
1.71
1.12
0.11
0.00
0.00
0.24
8.74
1.88
1.55
3.07
1.00
1.30
3.56
Preliminary Site Assessement NGE-TFT Project #5969-21
Proposed Lots 1-12, Palaterra Subd. – Anchorage, AK
Colony Builders, Inc.
March 8, 2021
Page 1 of 1
11301 Olive Lane Anchorage, Alaska 99515 ∙ Phone: (907) 344 -5934 ∙ Fax: (907) 344-5993 ∙ Website: www.nge-tft.com
August 5, 2021 NGE-TFT Project 5969-21
Colony Builders, Inc.
9420 Vanguard Drive
Anchorage, AK 99507
Attn: Bill Taylor - Owner
RE: ANTICIPATED SHALLOW GROUNDWATER CONDITIONS ACROSS
PROPOSED LOTS 1-11 OF THE PALATERRA SUBDIVISION - ANCHORAGE,
ALASKA
Bill,
The Municipality of Anchorage (MOA) Onsite Water & Wastewater code requires (as a condition
of plat approval) that the property owner establish the seasonal high groundwater level at any site
(prior to plat approval) to demonstrate that adequate separation distances can be maintained
between the bottom of any proposed septic drain fields and the seasonal high groundwater surface.
According to the MOA Onsite Water & Wastewater code, this can only be accomplished during
the months of May or October, as this is when the MOA deems that seasonal high groundwater
generally occurs in the Anchorage bowl.
We completed our subsurface exploration program at the project in June 2021. As such, we do
not currently have any groundwater level measurements during the MOA-approved seasonal high
groundwater periods (i.e., May or October). However, as we state in Section 5.2 of our June 2021
geotechnical report for this project, we did not observe any indications of groundwater during our
groundwater level monitoring efforts in June 2021. Furthermore, we do not anticipate any shallow
groundwater to occur (in any significant volumes) anywhere across the project site above a depth
of approximately 100 feet bgs at any time of the year. As such, we feel that the seasonal high
groundwater monitoring required by the MOA should not apply to this site, as we do not expect
any significant volumes of groundwater to occur at any depth above (or close to) the vertical limit
of any planned septic drain fields during any part of a given calendar year.
Sincerely,
Northern Geotechnical Engineering, Inc. d.b.a. Terra Firma Testing
Andrew C. Smith, CPG Keith F. Mobley, P.E.
Senior Geologist President
BRANDON J. MARCOTTCE 12601REGISTERED PROFESSIONAL ENGINEERE N G I N E E R I N G, LLC
ROPOSED WELLS
\
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LOT 3
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EFFECTIVE DEPTH
ABSORPTION TRENCH
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(a TP6
TOP OF STEEP SLOPE
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PROPOSED SEPTIC SYSTEM
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SOUGPOPEAKFLDVV EYDEEpTRENCH SYSTEM
PERK RATE: 40&1|N/|N 1.5OO-GALADVANTEXTANK w/
APPLICATION RATE: 2.0 GPD/SF AX -20 FILTER POD
600 GPD / 2.0 GPD/SF / 8'DEEP / 2 SIDES = 18.8 LF TRENCH REQUIRED (20 LF SPECIFIED)
BOTTOM OFTRENCH: 13/BELOVVGRADE
FLOW L/N `ELEVATON:5'BELOVVGRADE
TOP OF TRENCH: 6... ABOVE GRADE
RATED PVC (HOLES DOWN)
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1. GRADE AREA OVER TRENCH TODRAIN AWAY
2. PROVIDE 3'{}FCOVER OVER TRENCHEGAND 4'OVER SEPTIC TANK, OR2'
WITH 2"OFINSULATION
3. CHECK GROUNDWATER ATTIME DFCONSTRUCTION. |FLEVEL |GHIGHER
THAN PREVIOUSLY OBSERVED, CALL ENGINEER IMMEDIATELY
Depth
1-
2-
3-
4-
5-
6-
7-
8-
9-
10-
11-
12-
13-
14-
19-
20-
FT AND
FT BGS
I
(ENGINEER'S SEAL)
Project Name/No.:
Legal Description:
15-
16-
Date
Gross Time
Start/Stop
(HH:MM)
Slope Site Plan
(minutes/inch)
Net Time
(Minutes)
Depth to Water
Start/Stop
(feet BTOC)
Net Drop
(inches)
Reading
No.
COMMENTS
FINAL PERCOLATION RATE
17-
18-
PERFORMED IN ACCORDANCE WITH ALL STATE AND MUNICIPAL GUIDELINES IN EFFECT ON THIS DATE. DATE:
CERTIFY THAT THIS TEST WASPERFORMED BY:
S
L
O
P
E
WAS GROUNDWATER
OBSERVED ATD?
IF YES, AT WHAT DEPTH?
MEASURED DEPTH TO
GROUNDWATER
DATE OF MEASUREMENT
Date Performed:
Northern Geotechnical Engineering, Inc.
Terra Firma Testing
11301 Olive Lane
Anchorage, AK 99515
(907)344-5934
Soils Log - Percolation Test
Proposed Lot 1, Palaterra Subd.
16:43 / 17:13
17:15 / 17:45
17:47 / 18:17
12:05 / 12:35
12:40 / 16:40
11.630 / 11.665
240
6/16
6/16
6/16
80 6 in./4 in.
10.43 10.93
June 16, 2021
6/16/21 7/16
7/2/21
Proposed Lots 1-11, Palaterra Subd. / 5969-21
Colony Builders, Inc.
No
N/A
None
1
Soak
2
3
4
30
30
30
30
0
Andrew C. Smith, CPG Keith F. Mobley, P.E.
6/25/21
(feet)
24-
25-
21-
22-
23-
PERC HOLE/CASING DIAMETER
Test Performed For:
Borehole ID: P1
Drilled On: 6/14/21
TEST RUN BETWEEN CASING S/U 1.20
11.630 / 11.630
11.630 / 11.660
11.630 / 11.660
11.630 / 11.660
OL
ML
GM
ML
SEE
SITE
MAP
SEE
SITE
MAP
Depth
1-
2-
3-
4-
5-
6-
7-
8-
9-
10-
11-
12-
13-
14-
19-
20-
FT AND
FT BGS
I
(ENGINEER'S SEAL)
Project Name/No.:
Legal Description:
15-
16-
Date
Gross Time
Start/Stop
(HH:MM)
Slope Site Plan
(minutes/inch)
Net Time
(Minutes)
Depth to Water
Start/Stop
(feet BTOC)
Net Drop
(inches)
Reading
No.
COMMENTS
FINAL PERCOLATION RATE
17-
18-
PERFORMED IN ACCORDANCE WITH ALL STATE AND MUNICIPAL GUIDELINES IN EFFECT ON THIS DATE. DATE:
CERTIFY THAT THIS TEST WASPERFORMED BY:
S
L
O
P
E
WAS GROUNDWATER
OBSERVED ATD?
IF YES, AT WHAT DEPTH?
MEASURED DEPTH TO
GROUNDWATER
DATE OF MEASUREMENT
Date Performed:
Northern Geotechnical Engineering, Inc.
Terra Firma Testing
11301 Olive Lane
Anchorage, AK 99515
(907)344-5934
Soils Log - Percolation Test
Proposed Lot 2, Palaterra Subd.
15:04 / 15:12
15:13 / 15:21
15:22 / 15:31
13:22 / 13:30
14:55 / 15:03 8
2 6 in./4 in.
12.86 13.36
7/2/21
June 17, 2021
3
4
5
6/17/21
6/25/21
8
8
8
9
15:33 / 15:42 9
Proposed Lots 1-11, Palaterra Subd. / 5969-21
Colony Builders, Inc.
No
N/A
None
1
Andrew C. Smith, CPG Keith F. Mobley, P.E.
2
6
6
(feet)
24-
25-
21-
22-
23-
PERC HOLE/CASING DIAMETER
Test Performed For:
Borehole ID: P2
Drilled On: 6/14/21
TEST RUN BETWEEN CASING S/U 1.10
13.960 / 14.460
13.960 / 14.460
13.960 / 14.460
13.960 / 14.460
13.960 / 14.460
13.960 / 14.460
6
6
6
6
6
SEE
SITE
MAP
SEE
SITE
MAP
OL
SM
Depth
1-
2-
3-
4-
5-
6-
7-
8-
9-
10-
11-
12-
13-
14-
19-
20-
FT AND
FT BGS
I
(ENGINEER'S SEAL)
Project Name/No.:
Legal Description:
15-
16-
Date
Gross Time
Start/Stop
(HH:MM)
Slope Site Plan
(minutes/inch)
Net Time
(Minutes)
Depth to Water
Start/Stop
(feet BTOC)
Net Drop
(inches)
Reading
No.
COMMENTS
FINAL PERCOLATION RATE
17-
18-
PERFORMED IN ACCORDANCE WITH ALL STATE AND MUNICIPAL GUIDELINES IN EFFECT ON THIS DATE. DATE:
CERTIFY THAT THIS TEST WASPERFORMED BY:
S
L
O
P
E
WAS GROUNDWATER
OBSERVED ATD?
IF YES, AT WHAT DEPTH?
MEASURED DEPTH TO
GROUNDWATER
DATE OF MEASUREMENT
Date Performed:
Northern Geotechnical Engineering, Inc.
Terra Firma Testing
11301 Olive Lane
Anchorage, AK 99515
(907)344-5934
Soils Log - Percolation Test
Proposed Lot 3, Palaterra Subd.
18.650 / 18.765
20 6 in./4 in.
17.85 18.35
7/2/21
June 15, 2021
3
4
5
6/15/21
6/25/21
30
Proposed Lots 1-11, Palaterra Subd. / 5969-21
Colony Builders, Inc.
No
N/A
None
1
Andrew C. Smith, CPG Keith F. Mobley, P.E.
2
6
7 10 8/16
(feet)
24-
25-
21-
22-
23-
PERC HOLE/CASING DIAMETER
Test Performed For:
Borehole ID: P3
Drilled On: 6/15/21
TEST RUN BETWEEN CASING S/U 0.80
12:59 / 13:29
8/16
9/16
10
10
10
10
10
8/16
1 6/16
7/16
8/16
18.650 / 18.685
18.650 / 18.690
18.650 / 18.690
18.650 / 18.695
18.650 / 18.690
18.650 / 18.690
13:37 / 13:47
13:49 / 13:59
14:00 / 14:10
14:12 / 14:22
14:33 / 14:43
14:45 / 14:55
SEE
SITE
MAP
SEE
SITE
MAP
26-
OL
ML
ML
ML
Depth
1-
2-
3-
4-
5-
6-
7-
8-
9-
10-
11-
12-
13-
14-
19-
20-
FT AND
FT BGS
I
(ENGINEER'S SEAL)
Project Name/No.:
Legal Description:
15-
16-
Date
Gross Time
Start/Stop
(HH:MM)
Slope Site Plan
(minutes/inch)
Net Time
(Minutes)
Depth to Water
Start/Stop
(feet BTOC)
Net Drop
(inches)
Reading
No.
COMMENTS
FINAL PERCOLATION RATE
17-
18-
PERFORMED IN ACCORDANCE WITH ALL STATE AND MUNICIPAL GUIDELINES IN EFFECT ON THIS DATE. DATE:
CERTIFY THAT THIS TEST WASPERFORMED BY:
S
L
O
P
E
WAS GROUNDWATER
OBSERVED ATD?
IF YES, AT WHAT DEPTH?
MEASURED DEPTH TO
GROUNDWATER
DATE OF MEASUREMENT
Date Performed:
Northern Geotechnical Engineering, Inc.
Terra Firma Testing
11301 Olive Lane
Anchorage, AK 99515
(907)344-5934
Soils Log - Percolation Test
Proposed Lot 4, Palaterra Subd.
13:28 / 13:38
13:40 / 13:50
13:51 / 14:01
12:43 / 13:13
13:17 / 13:27
11 6 in./4 in.
15.11 15.61
7/2/21
June 17, 2021
3
4
5
6/17/21
6/25/21
30
Proposed Lots 1-11, Palaterra Subd. / 5969-21
Colony Builders, Inc.
No
N/A
None
1
Andrew C. Smith, CPG Keith F. Mobley, P.E.
2
6 14:02 / 14:12 17.650 / 17.730
7 14:13 / 14:23 10 17.650 / 17.730
(feet)
24-
25-
21-
22-
23-
PERC HOLE/CASING DIAMETER
Test Performed For:
Borehole ID: P4
Drilled On: 6/15/21
TEST RUN BETWEEN CASING S/U 2.54
17.650 / 18.090
17.650 / 17.750
17.650 / 17.735
17.650 / 17.735
17.650 / 17.735
10
10
10
10
10
5 5/16
1 3/16
1
1
1
15/16
15/16
SEE
SITE
MAP
SEE
SITE
MAP
OL
ML
GM
SM
ML
Depth
1-
2-
3-
4-
5-
6-
7-
8-
9-
10-
11-
12-
13-
14-
19-
20-
FT AND
FT BGS
I
(ENGINEER'S SEAL)
Project Name/No.:
Legal Description:
15-
16-
Date
Gross Time
Start/Stop
(HH:MM)
Slope Site Plan
(minutes/inch)
Net Time
(Minutes)
Depth to Water
Start/Stop
(feet BTOC)
Net Drop
(inches)
Reading
No.
COMMENTS
FINAL PERCOLATION RATE
17-
18-
PERFORMED IN ACCORDANCE WITH ALL STATE AND MUNICIPAL GUIDELINES IN EFFECT ON THIS DATE. DATE:
CERTIFY THAT THIS TEST WASPERFORMED BY:
S
L
O
P
E
WAS GROUNDWATER
OBSERVED ATD?
IF YES, AT WHAT DEPTH?
MEASURED DEPTH TO
GROUNDWATER
DATE OF MEASUREMENT
Date Performed:
Northern Geotechnical Engineering, Inc.
Terra Firma Testing
11301 Olive Lane
Anchorage, AK 99515
(907)344-5934
Soils Log - Percolation Test
Proposed Lot 5, Palaterra Subd.
14:27 / 14:57
15:01 / 15:31
15:43 / 16:13
10:02 / 10:32
10:20 / 14:25
14.250 / 14.300
14.250 / 14.250
14.250 / 14.315
14.250 / 14.310
14.250 / 14.315
245
12/16
12/16
12/16
40 6 in./4 in.
13.07 13.57
10/16
7/2/21
Proposed Lots 1-11, Palaterra Subd. / 5969-21 June 7, 2021
Colony Builders, Inc.
No
N/A
None
1
Soak
2
3
4
6/7/21 30
30
30
30
0
Andrew C. Smith, CPG Keith F. Mobley, P.E.
6/18/21
(feet)
24-
25-
21-
22-
23-
PERC HOLE/CASING DIAMETER
Test Performed For:
Borehole ID: P5
Drilled On: 6/4/21
TEST RUN BETWEEN CASING S/U 1.180
SEE
SITE
MAP
SEE
SITE
MAP
OL
SM
Depth
1-
2-
3-
4-
5-
6-
7-
8-
9-
10-
11-
12-
13-
14-
19-
20-
FT AND FT BGS
I
(ENGINEER'S SEAL)
Project Name/No.:
Legal Description:
15-
16-
Date
Gross Time
Start/Stop
(HH:MM)
Slope Site Plan
(minutes/inch)
Net Time
(Minutes)
Depth to Water
Start/Stop
(feet BTOC)
Net Drop
(inches)
Reading
No.
COMMENTS
FINAL PERCOLATION RATE
17-
18-
PERFORMED IN ACCORDANCE WITH ALL STATE AND MUNICIPAL GUIDELINES IN EFFECT ON THIS DATE. DATE:
CERTIFY THAT THIS TEST WASPERFORMED BY:
S
L
O
P
E
WAS GROUNDWATER
OBSERVED ATD?
IF YES, AT WHAT DEPTH?
MEASURED DEPTH TO
GROUNDWATER
DATE OF MEASUREMENT
Date Performed:
Northern Geotechnical Engineering, Inc.
Terra Firma Testing
11301 Olive Lane
Anchorage, AK 99515
(907)344-5934
Soils Log - Percolation Test
Proposed Lot 6, Palaterra Subd.
14:18 / 14:48
14:45 / 15:15
15:39 / 15:50
09:43 / 10:13
10:15 / 14:18
17.545 / 17.570
17.545 / 17.545
17.545 / 17.565
17.545 / 17.570
17.545 / 17.565
5/16
5/16
6 in./4 in.
Proposed Lots 1-11, Palaterra Subd. / 5969-21 June 7, 2021
Colony Builders, Inc.
No
N/A
None
1
Soak
2
3
4
6/7/21 30
30
30
30
243 0
4/16
4/16
120
15.44 15.94
Keith F. Mobley, P.E.Andrew C. Smith, CPG 7/2/21
6/18/21
(feet)
24-
25-
21-
22-
23-
PERC HOLE/CASING DIAMETER
Test Performed For:
Borehole ID: P6
Drilled On: 6/4/21
CASING S/UTEST RUN BETWEEN 2.105 ft
SEE
SITE
MAP
SEE
SITE
MAP
OL
ML
GM
Depth
1-
2-
3-
4-
5-
6-
7-
8-
9-
10-
11-
12-
13-
14-
19-
20-
FT AND
FT BGS
I
(ENGINEER'S SEAL)
Project Name/No.:
Legal Description:
15-
16-
Date
Gross Time
Start/Stop
(HH:MM)
Slope Site Plan
(minutes/inch)
Net Time
(Minutes)
Depth to Water
Start/Stop
(feet BTOC)
Net Drop
(inches)
Reading
No.
COMMENTS
FINAL PERCOLATION RATE
17-
18-
PERFORMED IN ACCORDANCE WITH ALL STATE AND MUNICIPAL GUIDELINES IN EFFECT ON THIS DATE. DATE:
CERTIFY THAT THIS TEST WASPERFORMED BY:
S
L
O
P
E
WAS GROUNDWATER
OBSERVED ATD?
IF YES, AT WHAT DEPTH?
MEASURED DEPTH TO
GROUNDWATER
DATE OF MEASUREMENT
Date Performed:
Northern Geotechnical Engineering, Inc.
Terra Firma Testing
11301 Olive Lane
Anchorage, AK 99515
(907)344-5934
Soils Log - Percolation Test
Proposed Lot 7, Palaterra Subd.
14:10 / 14:40
14:43 / 15:13
15:36 / 15:56
09:35 / 10:05
10:08 / 14:10
19.910 / 19.940
19.910 / 19.910
19.910 / 19.935
19.910 / 19.935
19.910 / 19.935
242
5/16
5/16
5/16
96 6 in./4 in.
18.24 18.74
7/2/21
Proposed Lots 1-11, Palaterra Subd. / 5969-21 June 7, 2021
Colony Builders, Inc.
No
N/A
None
1
Soak
2
3
4
6/7/21 30
30
30
30
6/16
0
Andrew C. Smith, CPG Keith F. Mobley, P.E.
6/18/21
(feet)
24-
25-
21-
22-
23-
PERC HOLE/CASING DIAMETER
Test Performed For:
Borehole ID: P7
Drilled On: 6/4/21
TEST RUN BETWEEN CASING S/U 1.670
SEE
SITE
MAP
SEE
SITE
MAP
26-
27-
OL
ML
ML
SM
Depth
1-
2-
3-
4-
5-
6-
7-
8-
9-
10-
11-
12-
13-
14-
19-
20-
FT AND
FT BGS
I
(ENGINEER'S SEAL)
Project Name/No.:
Legal Description:
15-
16-
Date
Gross Time
Start/Stop
(HH:MM)
Slope Site Plan
(minutes/inch)
Net Time
(Minutes)
Depth to Water
Start/Stop
(feet BTOC)
Net Drop
(inches)
Reading
No.
COMMENTS
FINAL PERCOLATION RATE
17-
18-
PERFORMED IN ACCORDANCE WITH ALL STATE AND MUNICIPAL GUIDELINES IN EFFECT ON THIS DATE. DATE:
CERTIFY THAT THIS TEST WASPERFORMED BY:
S
L
O
P
E
WAS GROUNDWATER
OBSERVED ATD?
IF YES, AT WHAT DEPTH?
MEASURED DEPTH TO
GROUNDWATER
DATE OF MEASUREMENT
Date Performed:
Northern Geotechnical Engineering, Inc.
Terra Firma Testing
11301 Olive Lane
Anchorage, AK 99515
(907)344-5934
Soils Log - Percolation Test
Proposed Lot 8, Palaterra Subd.
16:34 / 16:44
16:47 / 16:57
16:58 / 17:08
15:50 / 16:20
16:22 / 16:32
23 6 in./4 in.
13.22 13.72
7/2/21
June 16, 2021
3
4
5
6/16/21
6/25/21
30
Proposed Lots 1-11, Palaterra Subd. / 5969-21
Colony Builders, Inc.
No
N/A
None
1
Andrew C. Smith, CPG Keith F. Mobley, P.E.
2
6 17:10 / 17:20 15.200 / 15.230
7 17:22 / 17:32 10 15.200 / 15.235 7/16
(feet)
24-
25-
21-
22-
23-
PERC HOLE/CASING DIAMETER
Test Performed For:
Borehole ID: P8
Drilled On: 6/16/21
TEST RUN BETWEEN CASING S/U 1.98
15.200 / 15.285
15.200 / 15.230
15.200 / 15.230
15.200 / 15.235
15.200 / 15.230
6/16
6/16
10
10
10
10
10
7/16
1
6/16
6/16
SEE
SITE
MAP
SEE
SITE
MAP
OL
SM
SM
Depth
1-
2-
3-
4-
5-
6-
7-
8-
9-
10-
11-
12-
13-
14-
19-
20-
FT AND
FT BGS
I
(ENGINEER'S SEAL)
Project Name/No.:
Legal Description:
15-
16-
Date
Gross Time
Start/Stop
(HH:MM)
Slope Site Plan
(minutes/inch)
Net Time
(Minutes)
Depth to Water
Start/Stop
(feet BTOC)
Net Drop
(inches)
Reading
No.
COMMENTS
FINAL PERCOLATION RATE
17-
18-
PERFORMED IN ACCORDANCE WITH ALL STATE AND MUNICIPAL GUIDELINES IN EFFECT ON THIS DATE. DATE:
CERTIFY THAT THIS TEST WASPERFORMED BY:
S
L
O
P
E
WAS GROUNDWATER
OBSERVED ATD?
IF YES, AT WHAT DEPTH?
MEASURED DEPTH TO
GROUNDWATER
DATE OF MEASUREMENT
Date Performed:
Northern Geotechnical Engineering, Inc.
Terra Firma Testing
11301 Olive Lane
Anchorage, AK 99515
(907)344-5934
Soils Log - Percolation Test
Proposed Lot 9, Palaterra Subd.
09:23 / 09:33
09:34 / 09:44
09:45 / 09:55
08:37 / 09:07
09:11 / 09:21
6 6 in./4 in.
10.60 11.10
7/2/21
June 17, 2021
3
4
5
6/17/21
6/25/21
30
Proposed Lots 1-11, Palaterra Subd. / 5969-21
Colony Builders, Inc.
No
N/A
None
1
Andrew C. Smith, CPG Keith F. Mobley, P.E.
2
6 09:58 / 10:08 12.560 / 12.695
7 10:10 / 10:20 10 12.560 / 12.690
(feet)
24-
25-
21-
22-
23-
PERC HOLE/CASING DIAMETER
Test Performed For:
Borehole ID: P9
Drilled On: 6/16/21
TEST RUN BETWEEN CASING S/U 1.96
12.560 / 12.965
12.560 / 12.695
12.560 / 12.690
12.560 / 12.690
12.560 / 12.695
10
10
10
10
10
4 14/16
1 10/16
1 9/16
1 9/16
1 9/16
1 10/16
1 10/16
SEE
SITE
MAP
SEE
SITE
MAP
OL
ML
SM
Depth
1-
2-
3-
4-
5-
6-
7-
8-
9-
10-
11-
12-
13-
14-
19-
20-
FT AND
FT BGS
I
(ENGINEER'S SEAL)
Project Name/No.:
Legal Description:
15-
16-
Date
Gross Time
Start/Stop
(HH:MM)
Slope Site Plan
(minutes/inch)
Net Time
(Minutes)
Depth to Water
Start/Stop
(feet BTOC)
Net Drop
(inches)
Reading
No.
COMMENTS
FINAL PERCOLATION RATE
17-
18-
PERFORMED IN ACCORDANCE WITH ALL STATE AND MUNICIPAL GUIDELINES IN EFFECT ON THIS DATE. DATE:
CERTIFY THAT THIS TEST WASPERFORMED BY:
S
L
O
P
E
WAS GROUNDWATER
OBSERVED ATD?
IF YES, AT WHAT DEPTH?
MEASURED DEPTH TO
GROUNDWATER
DATE OF MEASUREMENT
Date Performed:
Northern Geotechnical Engineering, Inc.
Terra Firma Testing
11301 Olive Lane
Anchorage, AK 99515
(907)344-5934
Soils Log - Percolation Test
Proposed Lot 10, Palaterra Subd.
16:08 / 16:13
16:14 / 16:19
16:20 / 16:26
10:34 / 11:04
16:01 / 16:06
27 6 in./4 in.
15.55 16.05
7/2/21
June 17, 2021
3
4
5
6/17/21
6/25/21
30
Proposed Lots 1-11, Palaterra Subd. / 5969-21
Colony Builders, Inc.
No
N/A
None
1
Andrew C. Smith, CPG Keith F. Mobley, P.E.
2
6 16:28 / 16:34 18.430 / 18.460
7 12:06 / 12:16 10 18.430 / 18.460 6/16
(feet)
24-
25-
21-
22-
23-
PERC HOLE/CASING DIAMETER
Test Performed For:
Borehole ID: P10
Drilled On: 6/15/21
TEST RUN BETWEEN CASING S/U 2.88
18.430 / 18.525
18.430 / 18.465
18.430 / 18.465
18.430 / 18.465
18.430 / 18.460
6/16
6/16
10
10
10
10
10
7/16
7/16
7/16
1 2/16
SEE
SITE
MAP
SEE
SITE
MAP
OL
ML
SM
ML
SM
SM
Depth
1-
2-
3-
4-
5-
6-
7-
8-
9-
10-
11-
12-
13-
14-
19-
20-
FT AND
FT BGS
I
(ENGINEER'S SEAL)
Project Name/No.:
Legal Description:
15-
16-
Date
Gross Time
Start/Stop
(HH:MM)
Slope Site Plan
(minutes/inch)
Net Time
(Minutes)
Depth to Water
Start/Stop
(feet BTOC)
Net Drop
(inches)
Reading
No.
COMMENTS
FINAL PERCOLATION RATE
17-
18-
PERFORMED IN ACCORDANCE WITH ALL STATE AND MUNICIPAL GUIDELINES IN EFFECT ON THIS DATE. DATE:
CERTIFY THAT THIS TEST WASPERFORMED BY:
S
L
O
P
E
WAS GROUNDWATER
OBSERVED ATD?
IF YES, AT WHAT DEPTH?
MEASURED DEPTH TO
GROUNDWATER
DATE OF MEASUREMENT
Date Performed:
Northern Geotechnical Engineering, Inc.
Terra Firma Testing
11301 Olive Lane
Anchorage, AK 99515
(907)344-5934
Soils Log - Percolation Test
Proposed Lot 11, Palaterra Subd.
16:08 / 16:13
16:14 / 16:19
16:20 / 16:26
15:56 / 16:00
16:01 / 16:06 5
1 6 in./4 in.
14.3 14.8
7/2/21
June 17, 2021
3
4
5
6/17/21
6/25/21
Proposed Lots 1-11, Palaterra Subd. / 5969-21
Colony Builders, Inc.
No
N/A
None
1 4
5
5
6
6
Andrew C. Smith, CPG Keith F. Mobley, P.E.
2
6 16:28 / 16:34 6 15.120 / 15.620
(feet)
24-
25-
21-
22-
23-
PERC HOLE/CASING DIAMETER
Test Performed For:
Borehole ID: P11
Drilled On: 6/15/21
TEST RUN BETWEEN CASING S/U 0.82
15.120 / 15.620
15.120 / 15.620
15.120 / 15.620
15.120 / 15.620
15.120 / 15.620
6
6
6
6
6
SEE
SITE
MAP
SEE
SITE
MAP
OL
ML
GM
ML
SM
Summary of Laboratory Test Results
Proposed Lots 1-11
Palaterra Subdivision
Anchorage, Alaska
NGE-TFT Project #:5969-21
Moisture Content Passing 0.02mm Frost Class.Unified Soil Classification
ASTM D2216 ASTM D7928 (MOA)ASTM D2487
(ft)(ft)(% By Dry Mass)(% By Mass)
Top Bottom Gravel Sand Silt/Clay
R1 S1 1.0 2.0 40.6 3.6 53.9 42.5 8.9 F2 (SM) Silty sand
R1 S2 4.0 5.0 11.4 34.5 21.4 44.1 N/A N/A (GM) Silty gravel w/ sand
R1 S3 14.0 15.0 2.8 49.5 46.9 3.6 N/A N/A (GW) Well-graded gravel w/ sand
R2 S2 2.0 3.0 18.9 32.6 44.3 23.1 10.3 F2 (SM) Silty sand w/ gravel
R2 S4 14.0 15.0 10.4 0.6 70.4 29.0 N/A N/A (SM) Silty sand
R3 S2 4.0 5.0 16.4 17.0 21.5 61.5 48.1 F4 (ML) Sandy silt w/ gravel
R3 S3 14.0 15.0 10.1 28.5 41.5 30.0 N/A N/A (SM) Silty sand w/ gravel
TP1 S1 9.0 10.0 9.0 40.8 30.3 28.9 N/A N/A (GM) Silty gravel w/ sand
TP2 S2 4.0 5.0 11.4 N/A N/A N/A N/A N/A N/A
TP2 S3 9.0 10.0 11.2 23.4 29.8 46.8 N/A N/A (SM) Silty sand w/ gravel
TP3 S2 4.0 5.0 27.6 N/A N/A N/A N/A N/A N/A
TP3 S3 9.0 10.0 19.5 9.8 16.1 74.1 N/A N/A (ML) Silt with sand
TP4 S2 4.0 5.0 17.2 N/A N/A N/A N/A N/A N/A
TP4 S3 9.0 10.0 9.4 31.1 27.9 41.0 N/A N/A (GM) Silty gravel w/ sand
TP5 S2 4.0 5.0 22.9 N/A N/A N/A N/A N/A N/A
TP5 S3 9.0 10.0 12.0 14.1 41.9 44.0 N/A N/A (SM) Silty sand
TP6 S2 4.0 5.0 25.3 N/A N/A N/A N/A N/A N/A
TP6 S3 9.0 10.0 21.9 3.4 14.0 82.6 N/A N/A (ML) Silt with sand
TP7 S2 4.0 5.0 17.0 N/A N/A N/A N/A N/A N/A
TP7 S3 9.0 10.0 23.7 18.6 9.2 72.2 N/A N/A (ML) Silt with gravel
TP8 S2 4.0 5.0 19.3 N/A N/A N/A N/A N/A N/A
TP8 S3 9.0 10.0 8.8 35.2 35.2 29.6 N/A N/A (SM) Silty sand w/ gravel
TP9 S2 4.0 5.0 16.5 N/A N/A N/A N/A N/A N/A
TP9 S3 9.0 10.0 7.1 10.8 66.0 23.2 N/A N/A (SM) Silty sand
TP10 S2 1.0 2.0 23.7 N/A N/A N/A N/A N/A N/A
TP10 S3 4.0 5.0 8.5 33.1 36.6 30.3 N/A N/A (SM) Silty sand w/ gravel
TP10 S4 9.0 10.0 14.5 3.2 45.9 50.9 N/A N/A (ML) Sandy silt
TP11 S2 0.5 1.5 39.8 23.2 55.2 21.6 5.0 F2 (SM) Silty sand w/ gravel
TP11 S3 4.0 5.0 7.8 35.1 30.9 34.0 N/A N/A (GM) Silty gravel w/ sand
TP11 S4 9.0 10.0 16.0 8.8 34.7 56.5 N/A N/A (ML) Sandy silt
P1 S1A 9.0 11.0 8.1 35.9 27.3 36.8 N/A N/A (GM) Silty gravel w/ sand
P1 S4 20.0 21.5 20.7 0.0 6.5 93.5 N/A N/A (ML) Silt
P2 S2 12.5 13.5 11.8 0.0 57.5 42.5 N/A N/A (SM) Silty sand
P2 S3 20.0 21.5 15.4 0.0 11.8 88.2 N/A N/A (ML) Silt
P3 S2 15.0 16.3 15.6 0.0 8.2 91.8 N/A N/A (ML) Silt
P3 S3 17.0 18.5 12.5 0.0 25.8 74.2 N/A N/A (ML) Silt with sand
P3 S4 25.0 26.5 12.0 7.5 29.7 62.8 N/A N/A (ML) Sandy silt
P4 S2 12.0 14.0 16.3 3.1 19.1 77.8 N/A N/A (ML) Silt with sand
P4 S3 14.0 16.0 9.2 0.0 63.3 36.7 N/A N/A (SM) Silty sand
P4 S4 23.0 25.0 18.9 0.0 3.5 96.5 N/A N/A (ML) Silt
P5 S2 13.0 13.5 8.1 43.3 45.3 11.4 N/A N/A (SP-SM) Poorly-graded sand w/ silt and gravel
P5 S3 19.0 21.0 6.1 31.0 41.4 27.6 N/A N/A (SM) Silty sand w/ gravel
P6 S3 15.0 17.0 6.1 39.8 29.5 30.7 N/A N/A (GM) Silty gravel w/ sand
P6 S4 22.0 24.0 2.3 35.3 55.6 9.1 N/A N/A (SW-SM) Well-graded sand w/ silt and gravel
P7 S4 17.0 19.0 6.9 35.6 38.0 26.4 N/A N/A (SM) Silty sand w/ gravel
P7 S5 25.0 27.0 2.8 38.5 53.0 8.5 N/A N/A (SW-SM) Well-graded sand w/ silt and gravel
P8 S1 10.0 12.0 5.4 39.4 34.9 25.7 N/A N/A (GM) Silty gravel w/ sand
P8 S2 12.0 14.0 7.5 20.1 46.9 33.0 N/A N/A (SM) Silty sand w/ gravel
P8 S3 20.0 22.0 6.7 35.6 32.3 32.1 N/A N/A (GM) Silty gravel w/ sand
P9 S1 9.5 11.0 6.3 0.0 55.4 44.6 N/A N/A (SM) Silty sand
P9 S2 17.0 19.0 4.3 0.0 75.1 24.9 N/A N/A (SM) Silty sand
P10 S2 12.5 14.5 6.6 42.8 32.1 25.1 N/A N/A (GM) Silty gravel w/ sand
P10 S3 14.5 16.0 12.7 15.0 29.8 55.2 N/A N/A (ML) Sandy silt w/ gravel
P10 S4 20.0 22.0 5.7 0.0 77.9 22.1 N/A N/A (SM) Silty sand
P11 S2 13.0 15.0 2.5 0.0 86.0 14.0 N/A N/A (SM) Silty sand
P11 S3 20.0 22.0 8.1 0.0 64.9 35.1 N/A N/A (SM) Silty sand
Exploration
ID
Sample
Number
Depth Interval Particle Size Analysis
ASTM C136/D7928/D6913
(% By Mass)