HomeMy WebLinkAboutMULBERRY CONNECTION - FDP200030 - - SUPPLEMENTAL INFORMATION
309 South Summit View Drive, Unit 6 | Fort Collins, Colorado 805241 | p. 303.629.6000 | www.ninyoandmoore.com
October 3, 2019
Project No. 501710003
Mr. Josh Heiney
Comunale Properties
1855 South Pearl Street, Suite 20
Denver, Colorado 80210
Subject: Supplemental Geotechnical Evaluation
Percolation Testing
Mulberry Connection
Redman Drive & NW Frontage Road
Fort Collins, Colorado
Reference: Ninyo & Moore, 2019, Geotechnical Evaluation, Proposed Poudre Valley
Development, Redman Drive & NW Frontage Road, Fort Collins, Colorado, dated
July 2.
Dear Mr. Heiney:
In accordance with your authorization, we have performed a supplemental geotechnical evaluation
for the proposed Mulberry Connection industrial project located at the northwest corner of Redman
Drive and Northwest Frontage Road in Fort Collins, Colorado (Figure 1). The purpose of our
supplemental geotechnical evaluation was to assess the percolation rate within the proposed
stormwater detention ponds (Figure 2). This report presents the results of the percolation testing.
Our referenced report dated July 2, 2019 presented our methodology, findings, conclusions, and
limitations regarding the geotechnical conditions and our geotechnical recommendations for the
proposed development. Recommendations and limitations provided in the referenced report
remain valid, except where superseded herein.
PROPOSED CONSTRUCTION
As a part of the proposed development, detention basins will be constructed to the south, west,
and east of the proposed structures. We understand the basins will require excavations ranging
from less than 1 foot to up to approximately 3 feet below existing site grades.
PERCOLATION TESTING
Percolation testing was performed by hand-excavating 12, approximately 8- to 10-inch diameter,
percolation holes that ranged from approximately 30 to 37 inches below the existing site grades.
Borings performed as a part of our subsurface exploration in the vicinity of the detention basins
Ninyo & Moore | Mulberry Connection Percolation Tests, Fort Collins, Colorado | 501710003 | October 3, 2019
were utilized for determination of soil profiles in the area. Along the eastern and southeastern
portion of the site, subsurface conditions generally consisted of approximately 2 to 4 feet of clay
loam underlain by clay alluvial soils to depths of approximately 9 to 9.5 feet below ground surface
(bgs). Sandy alluvial deposits were encountered below the clay alluvial deposits. Along the western
and southwestern portion of the site, approximately 4 feet of clay loam was encountered underlain
by sandy alluvial deposits. Groundwater was observed in our borings at depths of approximately
8.5 to 12 feet bgs.
Our percolation testing procedures consisted of excavating the percolation holes with an electric
auger. Once excavated, the sides of the holes were roughening, as needed, and the percolation
holes were pre-soaked. Approximately 2 inches of sand was added to the bottom of the holes prior
to the holes being pre-soaked for approximately 24 hours. In accordance with Larimer County
Health and Environment percolation testing requirements, each percolation test was conducted
over a 4-hour period with measurements obtained at 30-minute intervals. The water level drop in
the final 30-minute interval was used to calculate the percolation rate.
The results of the percolation testing are presented in Appendix A. In order to account for the site
variability, the limited number of tests performed, and to account for siltation, a correction factor of
2 should be applied to the calculated average percolation rate per basin.
This report is intended exclusively for use by the client. Any use or reuse of the findings,
conclusions, and/or recommendations of this report by parties other than the client is undertaken at
said parties’ sole risk.
We appreciate the opportunity to be of continued service to you during this phase of the project.
Respectfully submitted,
NINYO & MOORE
Kelley Lange, EI
Senior Staff Engineer
Brian F. Gisi, PE
Principal Engineer
KL/BFG
Attachments: Figure 1 – Site Location
Figure 2 – Percolation Test Locations
Appendix A – Percolation Test Results
Distribution: (1) Addressee (via email)
(1) Mr. Dan Skeehan, PE, Kimley Horn (via email)
10/3/2019
Ninyo & Moore | Mulberry Connection Percolation Tests, Fort Collins, Colorado | 501710003 | October 3, 2019
Appendix A
Photographic Documentation
FIGURES
FIGURE 1
bsm file no: 1710vmap0619501710003 | 10/19
REDMAN DRIVE AND NORTHWEST FRONTAGE ROAD
FORT COLLINS, COLORADO
POUDRE VALLEY DEVELOPMENT
SITE LOCATION
NOTE: DIMENSIONS, DIRECTIONS AND LOCATIONS ARE APPROXIMATE.
Source: US Geological Survey 7.5-minute topographic map, Fort Collins and Timnath, Colorado, 2016.
0 2000
FEET
NN
APPROXIMATE
SITE LOCATION
FIGURE 2
bsm file no: 1710sp0919501710003 | 9/19
PERCOLATION TEST LOCATIONS
FORT COLLINS, COLORADO
MULBERRY CONNECTION PERCOLATION TESTING
SOURCE: KIMLEY-HORN AND ASSOCIATES, 08/14/2019.
NOTE: DIMENSIONS, DIRECTIONS AND LOCATIONS ARE APPROXIMATE.
0 120
FEET
NN
Geotechnical & Environmental Sciences Consultants
LEGEND
Percolation Test LocationP4-3
P1-1
P1-2
P1-3
P2-1 P2-2 P2-3 P3-1 P3-2 P3-3
P4-3
P4-2
P4-1
REDMAN DRIVE NORTHWEST FRONTAGE ROAD
Ninyo & Moore | Mulberry Connection Percolation Tests, Fort Collins, Colorado | 501710003 | October 3, 2019
APPENDIX A
Percolation Tests
Project Number:501710003 Test Date:9/13/2019
Project:Mulberry Connection Tested By:FT
Location:Fort Collins Elevation:-+/- (MSL)
Hole Number Hole Depth Time Interval Initial Water
Level Height
at Start
Final Water
Level
Height at
End
Drop in
Water Level
Average
Percolation
Rate
Time Start Time Stop
(inches)(minutes)(inches)(inches)(inches)(min/in)(hh:mm)(hh:mm)
P1-1 37 0 29.00 29.00 0.00
Height of Sand/Gravel 30 29.00 27.00 2.00 15.00
added at bottom (in):2.0 30 28.50 27.50 1.00 30.00
30 29.50 25.50 4.00 7.50
30 29.00 25.00 4.00 7.50
30 29.00 27.00 2.00 15.00
30 29.50 27.00 2.50 12.00
30 28.50 26.50 2.00 15.00
30 29.00 27.00 2.00 15.00
P1-2 31 0 23.00 23.00 0.00
Height of Sand/Gravel 30 23.00 19.00 4.00 7.50
added at bottom (in):2.0 30 23.00 21.50 1.50 20.00
30 22.50 20.00 2.50 12.00
30 23.00 21.50 1.50 20.00
30 23.00 22.00 1.00 30.00
30 23.50 21.50 2.00 15.00
30 23.00 21.50 1.50 20.00
30 23.00 21.00 2.00 15.00
P1-3 32 30 24.00 24.00 1.25
Height of Sand/Gravel 30 24.00 23.00 1.00 30.00
added at bottom (in):2.0 30 25.00 24.00 1.00 30.00
30 23.50 21.50 2.00 15.00
30 24.00 22.50 1.50 20.00
30 24.00 21.50 2.50 12.00
30 24.50 22.00 2.50 12.00
30 24.00 21.00 3.00 10.00
30 23.50 21.50 2.00 15.00
Average Percolation Rate =15.00 min/in
Corrected Percolation Rate =30.00 min/in
PERCOLATION TEST RESULTS
Project Number:501710003 Test Date:9/13/2019
Project:Mulberry Connection Tested By:FT
Location:Fort Collins Elevation:-+/- (MSL)
Hole Number Hole Depth Time Interval Initial Water
Level Height
at Start
Final Water
Level
Height at
End
Drop in
Water Level
Average
Percolation
Rate
Time Start Time Stop
(inches)(minutes)(inches)(inches)(inches)(min/in)(hh:mm)(hh:mm)
P2-1 31 0 21.5 21.50 0.00
Height of Sand/Gravel 30 22 18 4.00 7.50
added at bottom (in):2.0 30 23 19.5 3.50 8.57
30 22.5 20.5 2.00 15.00
30 23 20.5 2.50 12.00
30 23 21.5 1.50 20.00
30 23.5 21 2.50 12.00
30 23 20 3.00 10.00
30 22.5 20 2.50 12.00
P2-2 33 0 24.5 24.50 0.00
Height of Sand/Gravel 30 24.5 22.5 2.00 15.00
added at bottom (in):2.0 30 25 22.5 2.50 12.00
30 25 22 3.00 10.00
30 25 22 3.00 10.00
30 24.5 22 2.50 12.00
30 25 23 2.00 15.00
30 25 22 3.00 10.00
30 25 23 2.00 15.00
P2-3 36 0 27 27.00 0.00
Height of Sand/Gravel 30 27 24.5 2.50 12.00
added at bottom (in):2.0 30 28 25.5 2.50 12.00
30 27.5 24 3.50 8.57
30 27.5 23 4.50 6.67
30 27 24 3.00 10.00
30 28 26 2.00 15.00
30 27.5 24.5 3.00 10.00
30 28 26 2.00 15.00
Average Percolation Rate =14.00 min/in
Corrected Percolation Rate =28.00 min/in
PERCOLATION TEST RESULTS
Project Number:501710003 Test Date:9/13/2019
Project:Mulberry Connection Tested By:FT
Location:Fort Collins Elevation:-+/- (MSL)
Hole Number Hole Depth Time Interval Initial Water
Level Height
at Start
Final Water
Level
Height at
End
Drop in
Water Level
Average
Percolation
Rate
Time Start Time Stop
(inches)(minutes)(inches)(inches)(inches)(min/in)(hh:mm)(hh:mm)
P3-1 33 0 24.5 24.50 0.00
Height of Sand/Gravel 30 24.5 20 4.50 6.67
added at bottom (in):2.0 30 24 21.5 2.50 12.00
30 24.5 21 3.50 8.57
30 24.5 22 2.50 12.00
30 25 23.5 1.50 20.00
30 25 22.5 2.50 12.00
30 24.5 23 1.50 20.00
30 25 23.5 1.50 20.00
P3-2 30 0 22 22.00 0.00
Height of Sand/Gravel 30 22 18 4.00 7.50
added at bottom (in):2.0 30 21 18.5 2.50 12.00
30 21 20 1.00 30.00
30 22 20 2.00 15.00
30 21.5 19 2.50 12.00
30 22 21 1.00 30.00
30 22.5 21 1.50 20.00
30 22 21 1.00 30.00
P3-3 30 0 22 22.00 0.00
Height of Sand/Gravel 30 22 20 2.00 15.00
added at bottom (in):2.0 30 21.5 20.5 1.00 30.00
30 22 20.5 1.50 20.00
30 22 19.5 2.50 12.00
30 23 22 1.00 30.00
30 21.5 20 1.50 20.00
30 22 20 2.00 15.00
30 22 21 1.00 30.00
Average Percolation Rate =26.67 min/in
Corrected Percolation Rate =53.33 min/in
PERCOLATION TEST RESULTS
Project Number:501710003 Test Date:9/13/2019
Project:Mulberry Connection Tested By:FT
Location:Fort Collins Elevation:-+/- (MSL)
Hole Number Hole Depth Time Interval Initial Water
Level Height
at Start
Final Water
Level
Height at
End
Drop in
Water Level
Average
Percolation
Rate
Time Start Time Stop
(inches)(minutes)(inches)(inches)(inches)(min/in)(hh:mm)(hh:mm)
P4-1 30 0 22 22.00 0.00
Height of Sand/Gravel 30 22 20 2.00 15.00
added at bottom (in):2.0 30 22 18.5 3.50 8.57
30 22.5 19.5 3.00 10.00
30 21.5 18 3.50 8.57
30 22 19.5 2.50 12.00
30 22 19.5 2.50 12.00
30 21 19 2.00 15.00
30 22 19.5 2.50 12.00
P4-2 30 0 21.5 21.50 0.00
Height of Sand/Gravel 30 21.5 18.5 3.00 10.00
added at bottom (in):2.0 30 22 18.5 3.50 8.57
30 22 20 2.00 15.00
30 23 22 1.00 30.00
30 21.5 20 1.50 20.00
30 22 20.5 1.50 20.00
30 22 20 2.00 15.00
30 22 20 2.00 15.00
P4-3 31 0 22 22.00 0.00
Height of Sand/Gravel 30 23 20 3.00 10.00
added at bottom (in):2.0 30 23 21 2.00 15.00
30 22.5 19.5 3.00 10.00
30 23 21 2.00 15.00
30 23.5 23 0.50 60.00
30 23 21 2.00 15.00
30 22.5 21 1.50 20.00
30 23 21.5 1.50 20.00
Average Percolation Rate =15.67 min/in
Corrected Percolation Rate =31.33 min/in
PERCOLATION TEST RESULTS