HomeMy WebLinkAbout012 Stormwater Management Design Report - TPS
STORMWATER MANAGEMENT
DESIGN REPORT
FOR:
TOWNEPLACE SUITES
LOT 1A EASTLAKE PROFESSIONAL
CENTER SUBDIVISION
BOZEMAN, MT
Prepared By:
Madison Engineering
895 Technology Drive, Suite 203
Bozeman, MT 59718
(406) 586-0262
January 2023
Page 1 of 2
TOWNEPLACE SUITES
LOT 1A OF EASTLAKE PROFESSISOANL CENTER SUBDIVSION
STORMWATER DESIGN REPORT
A. Introduction
This design report will give an overview of the stormwater system for the proposed 107 room
Towneplace Suites located on North 27th and Honor Lane in Bozeman, Montana.
The proposed commercial development will be constructed on B2 (Community Business
District) zoned property with associated on-site drive aisles, driveways, parking, pedestrian
walkways and landscaping. No off-site improvements are required.
The proposed storm water management system consists of overland sheet flow, catch basin/curb
inlets, curb & gutter and piping that will direct stormwater to an on-site RTank
retention/infiltration basin to serve the site. Off-site discharge is not proposed. Roof run-off is
collected via roof drain piping and directed to the stormwater basin as well. The infiltration
basin will be excavated to native gravels to permit maximum infiltration.
The following references were used in the preparation of this report:
a. COB Design Standards and Specifications Policy, 2004. Addendum #7
b. COB Modifications to Montana Public Works Standard Specifications (MPWSS)
The proposed drainage and grading plan are included in Appendix A of this report.
B. Native Soils and Groundwater Data
Soils on the subject property are typical for the area and are detailed in Appendix D – On-Site
Exploration Logs from section of the Geotechnical Report prepared by TD & H Engineering.
Groundwater depths were observed and recorded as part of the Geotechnical Investigation.
Groundwater depth was measured in monitoring well #10 at approximately 8 feet below the
existing ground surface. This test pit is located near the proposed underground stormwater basin.
C. Conveyance Capacity
The proposed private stormwater collection system was designed to convey the 25-year storm
event per the City of Bozeman standards. The conveyance structures include piping that directs
stormwater run-off to the on-site infiltration basins. Storm sewer piping and area drains/curb
inlets are proposed to collect and convey the stormwater run-off from the basins to the RTank
retention/infiltration basin. Stormwater run-off and piping calculations are included in
Appendix C of this report.
Page 2 of 2
D. Stormwater Retention/Infiltration Basin Calculation
Subsurface RTank infiltration chambers are proposed for this project. The stormwater runoff
from the site is proposed to be conveyed to the on-site RTank retention/infiltration basin and
ultimately infiltrate into native gravels.
The retention storage volume was sized based on the 10-year 2-hour design rainfall frequency in
accordance with the COB design standards. The rational method was used to determine post-
development stormwater flows. A runoff coefficient C of 0.90 was used for impervious areas and
a C value of 0.20 was used for landscaped areas. The calculations for all RTank stormwater
storage facility is included in Appendix B of this report. The proposed stormwater facility
reduces the post-development off-site runoff rate to nearly zero. All impervious surface runoff is
conveyed to the infiltration retention systems and then infiltrates into the ground.
F. Stormwater Facility Maintenance
The proposed storm drainage facilities will be privately operated and maintained by the property
owner of the on-site development. Included in Appendix E is a proposed maintenance program
for the stormwater collection and infiltration systems as well as the O&M Manual for the RTank
system.
Appendix
A. Grading & Drainage Design
B. RTank Basin Calculations
C. Stormwater Run-off and Piping Calculations
D. On-Site Exploration Logs
E. O&M Manual
APPENDIX
Appendix A Grading & Drainage Design
Appendix B Tank Basin Calculations
Appendix B
TownePlace Suites
Rtank Basin Sizing Calculations
Design Rainfall Freq. 10 year - 2 Hour Event
IDF coefficient a 0.64
IDF coefficient b
IDF coefficient n 0.65
Post-development Conditions
Square feet Acres C
Impervious 77,410 1.78 0.90
Landscaped 13,932 0.32 0.20
Total area 91,342 2.10
Composite C 0.79
Retention Basin Calculation:
Q = CIA
C = 0.79 (post-development)
I = 0.41 in/hr (10-yr, 2-hr storm)
A = 2.10 acres
Qpost = 0.68 cfs
Required retention storage (ft3) =4,885 ft3 (10-yr, 2-hr storm)
R-Tank Volume Calculation
Length 28.15 inches 2.35 ft
Width 15.75 inches 1.31 ft
Height (Double) 33.86 inches 2.82 ft
# of Modules
Basin Area Horizontally
Length 56.30 sf 24
Width 11.81 sf 9
Area 665.04 sf 216 per layer
Height (ft) # of Modules
Double 2.82 1
Single 1.44 1
Mini 0.79 1
R-Tank Module Height 5.05 ft 1 Double
R-Tank LD Volume 3360 sf (Gross Volume)
R-Tank Efficieny 95%
Total R-Tank HD Volume 3,192 ft3 (Net Volume)
Rtank Module Size
Gravel Volume Calculation
Perimeter Gravel Width 3 ft
Perimeter Gravel Depth
Top 0.5 ft
Bottom 1.3 ft
Total 1.8 ft
Top and Bottom Rtank Basin
Length 56.30 62.30 ft
Width 11.81 17.81 ft
Area 1,109.7 ft2
Volume 1,997.5 ft3 @40% =799.0 ft3
Sides
Height
Gross Volume 5,606.9
Less RTank Volume 3,360.1
Net Basin Volume 2,246.7 ft3 @40%898.7 ft3
Gravel Volume 1,697.7 ft3
Total Basin Volume 4889.8 ft3
Finish Grade 4670.00 ft
Top of Gravel 4669.00 ft
Top of Rtank 4668.50 ft
Bottom of Rtank 4663.45 ft
Bottom of Gravel 4662.15 ft
Appendix C Stormwater Run-off and Piping Calculations
Appendix C
TownePlace Suites
Stormwater Basin Runoff Calculations
Design Rainfall Freq. 25 year
IDF coefficient a 0.78
IDF coefficient b
IDF coefficient n 0.64
Basin A
Post-development Calculations
C
Areas (ft2):Landscape 994 0.20
Impervious 9,811 0.90
Total: 10,805
total area: 0.25 acres
composite C: 0.84
Overland tc
average slope: 2.5 percent
travel distance: 100 feet
tc:4 minutes
Total tc:4 minutes
intensity at tc (fig 23):4.69 in/hr
Basin A post-devel peak runoff: 0.97 cfs Pipe A 4.4 cfs
Basin B
Post-development Calculations
C
Areas (ft2):Landscape 0.20
Impervious 8,499 0.90
Total: 8,499
total area: 0.20 acres
composite C: 0.90
Overland tcaverage slope: 3 percent
travel distance: 175 feet
tc:3 minutes
Total tc:3 minutes
intensity at tc (fig 23):4.87 in/hr
Basin B post-devel peak runoff: 0.86 cfs
Cummulative Basin A & B post-devel peak runoff: 1.83 cfs Pipe B 2.0 cfs
Storm Runoff Calculation.xls
Appendix C
TownePlace Suites
Stormwater Basin Runoff Calculations
Basin E (Roof)
Post-development Calculations
C
Areas (ft2):Landscape 5,789 0.20
Impervious 22,887 0.90
Total: 28,676
total area: 0.66 acres
composite C: 0.76
Overland tc
average slope: 3 percent
travel distance: 175 feet
tc:6 minutes
Total tc:6 minutes
intensity at tc (fig 23):3.46 in/hr
Basin E post-devel peak runoff: 1.73 cfs
Basin E post-devel peak runoff: 0.86 cfs (1/2 of roof area)
Pipe E 0.9 cfs
Basin C
Post-development Calculations
C
Areas (ft2):Landscape 1,360 0.20
Impervious 13,326 0.90
Total: 14,686
total area: 0.34 acres
composite C: 0.84
Overland tc
average slope: 3 percent
travel distance: 175 feet
tc:5 minutes
Total tc:5 minutes
intensity at tc (fig 23):4.07 in/hr
Basin C post-devel peak runoff: 1.15 cfs
Cummulative Basin A, B, C & 1/2E post-devel peak runoff: 4.81 cfs Pipe C 8.9 cfs
Basin D
Post-development Calculations
C
Areas (ft2):Landscape 5,789 0.20
Impervious 22,887 0.90
Total: 28,676
total area: 0.66 acres
composite C: 0.76
Overland tc
average slope: 3 percent
travel distance: 175 feet
tc:6 minutes
Total tc:6 minutes
intensity at tc (fig 23):3.46 in/hr
Basin D post-devel peak runoff: 1.73 cfs
Cummulative Basin A, B, C, D & 1/2E post-devel peak runoff: 5.56 cfs Pipe C 8.9 cfs
Storm Runoff Calculation.xls
TOWNEPLACE SUITES
Pipe A
12" pipe from Basin A
CIRCULAR CHANNEL
Manning's Eqn.1.486 A R2/3 S1/2
n
Diameter,do (in) =12.0 Enter Value
Diameter,do (ft) =1.00
Units =1.486
n =0.013
Slope, S (ft/ft)0.015
Depth, y (ft) Theta (rad) Area, A (ft
2)
Wetted
Perimeter, P
(ft)
Hydraulic
Radius, R
(ft)
Top Width,
T (ft)
Hydraulic
Depth, D
(ft)
Section
Factor, Z
(ft5/2) Q (cfs) Q (gpm)
Q (gpd - 8
hour day) V (ft/s)
Energy, E
= V2/2g
(ft)
0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.0 0.0 0.0 0.0 0.00
0.05 0.90 0.01 0.45 0.03 0.44 0.03 0.00 0.0 9.4 4514.0 1.4 0.03
0.10 1.29 0.04 0.64 0.06 0.60 0.07 0.01 0.1 40.9 19625.3 2.2 0.08
0.15 1.59 0.07 0.80 0.09 0.71 0.10 0.02 0.2 95.2 45693.2 2.9 0.13
0.20 1.85 0.11 0.93 0.12 0.80 0.14 0.04 0.4 171.5 82317.8 3.4 0.18
0.25 2.09 0.15 1.05 0.15 0.87 0.18 0.06 0.6 268.3 128764.0 3.9 0.24
0.30 2.32 0.20 1.16 0.17 0.92 0.22 0.09 0.9 383.5 184083.0 4.3 0.29
0.35 2.53 0.24 1.27 0.19 0.95 0.26 0.12 1.1 514.9 247165.7 4.7 0.34
0.40 2.74 0.29 1.37 0.21 0.98 0.30 0.16 1.5 659.9 316771.3 5.0 0.39
0.45 2.94 0.34 1.47 0.23 0.99 0.34 0.20 1.8 815.7 391541.3 5.3 0.44
0.50 3.14 0.39 1.57 0.25 1.00 0.39 0.25 2.2 979.2 470004.2 5.6 0.48
0.55 3.34 0.44 1.67 0.26 0.99 0.44 0.30 2.6 1147.0 550573.2 5.8 0.52
0.60 3.54 0.49 1.77 0.28 0.98 0.50 0.35 2.9 1315.7 631535.4 6.0 0.55
0.65 3.75 0.54 1.88 0.29 0.95 0.57 0.41 3.3 1481.3 711030.3 6.1 0.58
0.70 3.96 0.59 1.98 0.30 0.92 0.64 0.47 3.7 1639.6 787010.4 6.2 0.60
0.75 4.19 0.63 2.09 0.30 0.87 0.73 0.54 4.0 1785.8 857172.7 6.3 0.62
0.80 4.43 0.67 2.21 0.30 0.80 0.84 0.62 4.3 1914.2 918827.1 6.3 0.62
0.85 4.69 0.71 2.35 0.30 0.71 1.00 0.71 4.5 2018.0 968622.6 6.3 0.62
0.90 5.00 0.74 2.50 0.30 0.60 1.24 0.83 4.7 2087.2 1001858.4 6.2 0.61
0.95 5.38 0.77 2.69 0.29 0.44 1.77 1.02 4.7 2104.3 1010052.7 6.1 0.57
1.00 6.28 0.79 3.14 0.25 0.00 4.4 1959.0 940326.2 5.6 0.48
Q =
0.0
1.0
2.0
3.0
4.0
5.0
6.0
7.0
0.00 0.20 0.40 0.60 0.80 1.00 1.20
Depth (ft)
Q (CFS)
V (ft/s)
E (ft)ydoT
THETA
TOWNEPLACE SUITES
Pipe B
12" pipe from Basin B
CIRCULAR CHANNEL
Manning's Eqn.1.486 A R2/3 S1/2
n
Diameter,do (in) =12.0 Enter Value
Diameter,do (ft) =1.00
Units =1.486
n =0.013
Slope, S (ft/ft)0.003
Depth, y (ft) Theta (rad) Area, A (ft
2)
Wetted
Perimeter, P
(ft)
Hydraulic
Radius, R
(ft)
Top Width,
T (ft)
Hydraulic
Depth, D
(ft)
Section
Factor, Z
(ft5/2) Q (cfs) Q (gpm)
Q (gpd - 8
hour day) V (ft/s)
Energy, E
= V2/2g
(ft)
0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.0 0.0 0.0 0.0 0.00
0.05 0.90 0.01 0.45 0.03 0.44 0.03 0.00 0.0 4.2 2018.7 0.6 0.01
0.10 1.29 0.04 0.64 0.06 0.60 0.07 0.01 0.0 18.3 8776.7 1.0 0.02
0.15 1.59 0.07 0.80 0.09 0.71 0.10 0.02 0.1 42.6 20434.6 1.3 0.03
0.20 1.85 0.11 0.93 0.12 0.80 0.14 0.04 0.2 76.7 36813.6 1.5 0.04
0.25 2.09 0.15 1.05 0.15 0.87 0.18 0.06 0.3 120.0 57585.0 1.7 0.05
0.30 2.32 0.20 1.16 0.17 0.92 0.22 0.09 0.4 171.5 82324.4 1.9 0.06
0.35 2.53 0.24 1.27 0.19 0.95 0.26 0.12 0.5 230.3 110535.8 2.1 0.07
0.40 2.74 0.29 1.37 0.21 0.98 0.30 0.16 0.7 295.1 141664.4 2.2 0.08
0.45 2.94 0.34 1.47 0.23 0.99 0.34 0.20 0.8 364.8 175102.6 2.4 0.09
0.50 3.14 0.39 1.57 0.25 1.00 0.39 0.25 1.0 437.9 210192.3 2.5 0.10
0.55 3.34 0.44 1.67 0.26 0.99 0.44 0.30 1.1 513.0 246223.8 2.6 0.10
0.60 3.54 0.49 1.77 0.28 0.98 0.50 0.35 1.3 588.4 282431.2 2.7 0.11
0.65 3.75 0.54 1.88 0.29 0.95 0.57 0.41 1.5 662.5 317982.4 2.7 0.12
0.70 3.96 0.59 1.98 0.30 0.92 0.64 0.47 1.6 733.3 351961.8 2.8 0.12
0.75 4.19 0.63 2.09 0.30 0.87 0.73 0.54 1.8 798.6 383339.3 2.8 0.12
0.80 4.43 0.67 2.21 0.30 0.80 0.84 0.62 1.9 856.1 410912.0 2.8 0.12
0.85 4.69 0.71 2.35 0.30 0.71 1.00 0.71 2.0 902.5 433181.2 2.8 0.12
0.90 5.00 0.74 2.50 0.30 0.60 1.24 0.83 2.1 933.4 448044.7 2.8 0.12
0.95 5.38 0.77 2.69 0.29 0.44 1.77 1.02 2.1 941.1 451709.3 2.7 0.11
1.00 6.28 0.79 3.14 0.25 0.00 2.0 876.1 420526.7 2.5 0.10
Q =
0.0
0.5
1.0
1.5
2.0
2.5
3.0
0.00 0.20 0.40 0.60 0.80 1.00 1.20
Depth (ft)
Q (CFS)
V (ft/s)
E (ft)ydoT
THETA
TOWNEPLACE SUITES
Pipe C
15" pipe from Basin A,B,C 1/2E
CIRCULAR CHANNEL
Manning's Eqn.1.486 A R2/3 S1/2
n
Diameter,do (in) =15.0 Enter Value
Diameter,do (ft) =1.25
Units =1.486
n =0.013
Slope, S (ft/ft)0.019
Depth, y (ft) Theta (rad) Area, A (ft
2)
Wetted
Perimeter, P
(ft)
Hydraulic
Radius, R
(ft)
Top Width,
T (ft)
Hydraulic
Depth, D
(ft)
Section
Factor, Z
(ft5/2) Q (cfs) Q (gpm)
Q (gpd - 8
hour day) V (ft/s)
Energy, E
= V2/2g
(ft)
0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.0 0.0 0.0 0.0 0.00
0.06 0.90 0.02 0.56 0.04 0.54 0.04 0.00 0.0 19.2 9211.3 1.9 0.05
0.13 1.29 0.06 0.80 0.08 0.75 0.09 0.02 0.2 83.4 40047.4 2.9 0.13
0.19 1.59 0.12 0.99 0.12 0.89 0.13 0.04 0.4 194.3 93241.5 3.7 0.22
0.25 1.85 0.17 1.16 0.15 1.00 0.17 0.07 0.8 350.0 167977.6 4.5 0.31
0.31 2.09 0.24 1.31 0.18 1.08 0.22 0.11 1.2 547.4 262755.9 5.1 0.40
0.38 2.32 0.31 1.45 0.21 1.15 0.27 0.16 1.7 782.6 375639.7 5.6 0.49
0.44 2.53 0.38 1.58 0.24 1.19 0.32 0.22 2.3 1050.8 504366.2 6.1 0.58
0.50 2.74 0.46 1.71 0.27 1.22 0.37 0.28 3.0 1346.7 646403.6 6.5 0.67
0.56 2.94 0.54 1.84 0.29 1.24 0.43 0.35 3.7 1664.5 798979.2 6.9 0.74
0.63 3.14 0.61 1.96 0.31 1.25 0.49 0.43 4.5 1998.1 959090.5 7.3 0.82
0.69 3.34 0.69 2.09 0.33 1.24 0.56 0.52 5.2 2340.6 1123499.6 7.5 0.88
0.75 3.54 0.77 2.22 0.35 1.22 0.63 0.61 6.0 2684.8 1288711.1 7.8 0.94
0.81 3.75 0.84 2.34 0.36 1.19 0.71 0.71 6.7 3022.8 1450928.3 8.0 0.99
0.88 3.96 0.92 2.48 0.37 1.15 0.80 0.82 7.5 3345.8 1605973.4 8.1 1.03
0.94 4.19 0.99 2.62 0.38 1.08 0.91 0.94 8.1 3644.1 1749146.5 8.2 1.05
1.00 4.43 1.05 2.77 0.38 1.00 1.05 1.08 8.7 3906.2 1874958.5 8.3 1.06
1.06 4.69 1.11 2.93 0.38 0.89 1.25 1.24 9.2 4117.9 1976571.3 8.3 1.06
1.13 5.00 1.16 3.12 0.37 0.75 1.55 1.45 9.5 4259.2 2044392.3 8.2 1.03
1.19 5.38 1.20 3.36 0.36 0.54 2.21 1.79 9.6 4294.0 2061113.5 7.9 0.98
1.25 6.28 1.23 3.93 0.31 0.00 8.9 3997.6 1918829.6 7.3 0.82
Q =
0.0
2.0
4.0
6.0
8.0
10.0
12.0
0.00 0.20 0.40 0.60 0.80 1.00 1.20 1.40
Depth (ft)
Q (CFS)
V (ft/s)
E (ft)ydoT
THETA
TOWNEPLACE SUITES
Pipe D
12 pipe from Basin A, B, C, D 1/2E
CIRCULAR CHANNEL
Manning's Eqn.1.486 A R2/3 S1/2
n
Diameter,do (in) =12.0 Enter Value
Diameter,do (ft) =1.00
Units =1.486
n =0.013
Slope, S (ft/ft)0.033
Depth, y (ft) Theta (rad) Area, A (ft
2)
Wetted
Perimeter, P
(ft)
Hydraulic
Radius, R
(ft)
Top Width,
T (ft)
Hydraulic
Depth, D
(ft)
Section
Factor, Z
(ft5/2) Q (cfs) Q (gpm)
Q (gpd - 8
hour day) V (ft/s)
Energy, E
= V2/2g
(ft)
0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.0 0.0 0.0 0.0 0.00
0.05 0.90 0.01 0.45 0.03 0.44 0.03 0.00 0.0 13.9 6695.4 2.1 0.07
0.10 1.29 0.04 0.64 0.06 0.60 0.07 0.01 0.1 60.6 29109.1 3.3 0.17
0.15 1.59 0.07 0.80 0.09 0.71 0.10 0.02 0.3 141.2 67774.0 4.3 0.28
0.20 1.85 0.11 0.93 0.12 0.80 0.14 0.04 0.6 254.4 122097.0 5.1 0.40
0.25 2.09 0.15 1.05 0.15 0.87 0.18 0.06 0.9 397.9 190987.9 5.8 0.52
0.30 2.32 0.20 1.16 0.17 0.92 0.22 0.09 1.3 568.8 273039.2 6.4 0.64
0.35 2.53 0.24 1.27 0.19 0.95 0.26 0.12 1.7 763.8 366605.9 6.9 0.75
0.40 2.74 0.29 1.37 0.21 0.98 0.30 0.16 2.2 978.8 469847.8 7.4 0.86
0.45 2.94 0.34 1.47 0.23 0.99 0.34 0.20 2.7 1209.9 580749.6 7.9 0.96
0.50 3.14 0.39 1.57 0.25 1.00 0.39 0.25 3.2 1452.4 697128.9 8.2 1.05
0.55 3.34 0.44 1.67 0.26 0.99 0.44 0.30 3.8 1701.3 816632.0 8.6 1.14
0.60 3.54 0.49 1.77 0.28 0.98 0.50 0.35 4.3 1951.5 936718.4 8.8 1.21
0.65 3.75 0.54 1.88 0.29 0.95 0.57 0.41 4.9 2197.1 1054628.3 9.1 1.27
0.70 3.96 0.59 1.98 0.30 0.92 0.64 0.47 5.4 2431.9 1167325.1 9.2 1.32
0.75 4.19 0.63 2.09 0.30 0.87 0.73 0.54 5.9 2648.7 1271392.5 9.3 1.35
0.80 4.43 0.67 2.21 0.30 0.80 0.84 0.62 6.3 2839.3 1362840.8 9.4 1.37
0.85 4.69 0.71 2.35 0.30 0.71 1.00 0.71 6.7 2993.1 1436699.5 9.4 1.36
0.90 5.00 0.74 2.50 0.30 0.60 1.24 0.83 6.9 3095.8 1485996.2 9.3 1.33
0.95 5.38 0.77 2.69 0.29 0.44 1.77 1.02 7.0 3121.1 1498150.2 9.0 1.26
1.00 6.28 0.79 3.14 0.25 0.00 6.5 2905.7 1394729.2 8.2 1.06
Q =
0.0
1.0
2.0
3.0
4.0
5.0
6.0
7.0
8.0
9.0
10.0
0.00 0.20 0.40 0.60 0.80 1.00 1.20
Depth (ft)
Q (CFS)
V (ft/s)
E (ft)ydoT
THETA
TOWNEPLACE SUITES
Pipe E
8 pipe from Roof
CIRCULAR CHANNEL
Manning's Eqn.1.486 A R2/3 S1/2
n
Diameter,do (in) =8.0 Enter Value
Diameter,do (ft) =0.67
Units =1.486
n =0.013
Slope, S (ft/ft)0.005
Depth, y (ft) Theta (rad) Area, A (ft
2)
Wetted
Perimeter, P
(ft)
Hydraulic
Radius, R
(ft)
Top Width,
T (ft)
Hydraulic
Depth, D
(ft)
Section
Factor, Z
(ft5/2) Q (cfs) Q (gpm)
Q (gpd - 8
hour day) V (ft/s)
Energy, E
= V2/2g
(ft)
0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.0 0.0 0.0 0.0 0.00
0.03 0.90 0.01 0.30 0.02 0.29 0.02 0.00 0.0 1.8 883.9 0.6 0.01
0.07 1.29 0.02 0.43 0.04 0.40 0.05 0.00 0.0 8.0 3843.1 1.0 0.01
0.10 1.59 0.03 0.53 0.06 0.48 0.07 0.01 0.0 18.6 8947.8 1.3 0.02
0.13 1.85 0.05 0.62 0.08 0.53 0.09 0.02 0.1 33.6 16119.7 1.5 0.04
0.17 2.09 0.07 0.70 0.10 0.58 0.12 0.02 0.1 52.5 25214.9 1.7 0.05
0.20 2.32 0.09 0.77 0.11 0.61 0.14 0.03 0.2 75.1 36047.6 1.9 0.06
0.23 2.53 0.11 0.84 0.13 0.64 0.17 0.05 0.2 100.8 48400.6 2.1 0.07
0.27 2.74 0.13 0.91 0.14 0.65 0.20 0.06 0.3 129.2 62031.0 2.2 0.08
0.30 2.94 0.15 0.98 0.16 0.66 0.23 0.07 0.4 159.7 76672.6 2.3 0.08
0.33 3.14 0.17 1.05 0.17 0.67 0.26 0.09 0.4 191.7 92037.4 2.4 0.09
0.37 3.34 0.20 1.11 0.18 0.66 0.30 0.11 0.5 224.6 107814.6 2.5 0.10
0.40 3.54 0.22 1.18 0.19 0.65 0.33 0.13 0.6 257.6 123668.9 2.6 0.11
0.43 3.75 0.24 1.25 0.19 0.64 0.38 0.15 0.6 290.1 139235.8 2.7 0.11
0.47 3.96 0.26 1.32 0.20 0.61 0.43 0.17 0.7 321.1 154114.4 2.7 0.12
0.50 4.19 0.28 1.40 0.20 0.58 0.49 0.20 0.8 349.7 167853.7 2.8 0.12
0.53 4.43 0.30 1.48 0.20 0.53 0.56 0.22 0.8 374.8 179927.1 2.8 0.12
0.57 4.69 0.32 1.56 0.20 0.48 0.66 0.26 0.9 395.2 189678.1 2.8 0.12
0.60 5.00 0.33 1.67 0.20 0.40 0.83 0.30 0.9 408.7 196186.5 2.8 0.12
0.63 5.38 0.34 1.79 0.19 0.29 1.18 0.37 0.9 412.1 197791.1 2.7 0.11
0.67 6.28 0.35 2.09 0.17 0.00 0.9 383.6 184137.1 2.4 0.09
Q =
0.0
0.5
1.0
1.5
2.0
2.5
3.0
0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70
Depth (ft)
Q (CFS)
V (ft/s)
E (ft)ydoT
THETA
Appendix D On-Site Exploration Logs
0
1.5
3
4.5
6
7.5
9
10.5
TOPSOIL: Lean CLAY, appears firm to stiff, dark brown,
moist
Lean CLAY, appears firm to stiff, brown, moist
Lean CLAY, appears soft to firm, light brown, moist
Poorly-Graded GRAVEL with Sand, relatively dense, dark
brown, moist, cobbles up to 6-inch
Bottom of Test Pit
0.8
1.6
6.5
8.8
LEGEND LOG OF TEST PIT TP-8Atterberg Limits
Field Moisture content North 27th Avenue Hotel
Bozeman, MontanaGroundwater Level
Grab/composite sample
Logged by:Nic Couch, EI
Excavated by:Earth Surgeons
Komatsu PC170LCGNP = Granular and Nonplastic
Note: The stratification lines represent approximate
boundaries between soil types. Actual boundaries
may be gradual or transitional.
March 14, 2022 B22-015-001
Figure No. 9
SheetGRAPHICLOGSOIL DESCRIPTION
SURFACE:Native Grasses
SURFACE ELEVATION:Not Measured
DEPTH (FT)GROUNDWATERSAMPLEDEPTH (FT)MOISTURE CONTENT
0 10 20 30 40 50
= MOISTURE CONTENT
1 of 1
0
1.5
3
4.5
6
7.5
9
10.5
TOPSOIL: Lean CLAY, appears firm to stiff, dark brown,
moist
Lean CLAY, appears firm to stiff, brown, moist
Lean CLAY, appears soft to firm, light brown, moist
Poorly-Graded GRAVEL with Sand, relatively dense, dark
brown, moist, cobbles up to 6-inch
Bottom of Test Pit
0.7
2.2
7.5
9.0
Ground
water
not
encoun-
tered
G
G
LEGEND LOG OF TEST PIT TP-9Atterberg Limits
Field Moisture content North 27th Avenue Hotel
Bozeman, MontanaGroundwater Level
Grab/composite sample
Logged by:Nic Couch, EI
Excavated by:Earth Surgeons
Komatsu PC170LCGNP = Granular and Nonplastic
Note: The stratification lines represent approximate
boundaries between soil types. Actual boundaries
may be gradual or transitional.
March 14, 2022 B22-015-001
Figure No. 10
SheetGRAPHICLOGSOIL DESCRIPTION
SURFACE:Unvegetated GRAVEL
SURFACE ELEVATION:Not Measured
DEPTH (FT)GROUNDWATERSAMPLEDEPTH (FT)MOISTURE CONTENT
0 10 20 30 40 50
= MOISTURE CONTENT
1 of 1
0
1.5
3
4.5
6
7.5
9
10.5
TOPSOIL: Lean CLAY, appears firm to stiff, dark brown,
moist
Lean CLAY, appears firm to stiff, brown, moist
Lean CLAY, appears soft to firm, light brown, moist
Poorly-Graded GRAVEL with Sand, relatively dense, dark
brown, moist, cobbles up to 6-inch
Bottom of Test Pit - Monitoring pipe set at 8.5 below original
ground surface
0.9
1.8
7.0
9.5
G
G
LEGEND LOG OF TEST PIT TP-10Atterberg Limits
Field Moisture content North 27th Avenue Hotel
Bozeman, MontanaGroundwater Level
Grab/composite sample
Logged by:Nic Couch, EI
Excavated by:Earth Surgeons
Komatsu PC170LCGNP = Granular and Nonplastic
Note: The stratification lines represent approximate
boundaries between soil types. Actual boundaries
may be gradual or transitional.
March 14, 2022 B22-015-001
Figure No. 11
SheetGRAPHICLOGSOIL DESCRIPTION
SURFACE:Unvegetated GRAVEL
SURFACE ELEVATION:Not Measured
DEPTH (FT)GROUNDWATERSAMPLEDEPTH (FT)MOISTURE CONTENT
0 10 20 30 40 50
= MOISTURE CONTENT
1 of 1
Appendix E O&M Manual
G:\MADISON ENGINEERING\PROJECTS\2021\21-120 TPS-FFIS Site Plan\Storm\Report\STORMWATER MAINTENANCE
PLAN.doc
STORMWATER MAINTENANCE PLAN
Towneplace Suites – Bozeman West
Owner’s responsibility for routine inspection and maintenance
1. Keep the inlets of the facilities free of leaves, rocks, and other debris.
2. See that litter and other debris are removed from inlets, swales, and vegetated and
paved areas.
3. Maintenance of the underground systems are as follows:
Minimum required maintenance includes a quarterly inspection during the
first year of operation and a yearly inspection thereafter. Utilize inspection
ports for inspections.
The inspection ports can be used to pump water into the system and re-
suspend accumulated sediment so that is may be pumped out. Flush and
pump as inspections deem necessary.
4. Property Owner to maintain and fund Operation and Maintenance of stormwater
facilities.
_______________________________
______________, Property Owner
Operation
Your ACF R-Tank System has been designed to function in conjunction with the engineered drainage system on your
site, the existing municipal infrastructure, and/or the existing soils and geography of the receiving watershed. Unless
your site included certain unique and rare features, the operation of your R-Tank System will be driven by naturally
occurring systems and will function autonomously. However, upholding a proper schedule of Inspection & Maintenance
is critical to ensuring continued functionality and optimum performance of the system.
Inspection
Both the R-Tank and all stormwater pre-treatment features incorporated into your site must be inspected regularly.
Inspection frequency for your system must be determined based on the contributing drainage area, but should never
exceed one year between inspections (six months during the first year of operation).
Inspections may be required more frequently for pre-treatment systems. You should refer to the manufacturer
requirements for the proper inspection schedule.
With the right equipment your inspection and measurements can be accomplished from the surface without physically
entering any confined spaces. If your inspection does require confined space entry, you MUST follow all local/regional
requirements as well as OSHA standards.
R-Tank Systems may incorporate Inspection Ports, Maintenance Ports, and/or adjoining manholes. Each of these
features are easily accessed by removing the lid at the surface. With the cover removed, a visual inspection can be
performed to identify sediment deposits within the structure. Using a flashlight, ALL access points should be examined
to complete a thorough inspection.
Inspection Ports
Usually located centrally in the R-Tank System, these perforated columns are designed to give the user a base-linesediment depth across the system floor.
Maintenance Ports
Usually located near the inlet and outlet connections, you’ll likely find deeper deposits of heavier sediments whencompared to the Inspection Ports.
Manholes
Most systems will include at least two manholes - one at the inlet and another at the outlet. There may be more than one location where stormwater enters the system, which would result in additional manholes to inspect.
Bear in mind that these manholes often include a sump below the invert of the pipe connecting to the R-Tank.
These sumps are designed to capture sediment before it reaches the R-Tank, and they should be kept clean to ensure they function properly. However, existence of sediment in the sump does NOT necessarily mean sediment
has accumulated in the R-Tank.
After inspecting the bottom of the structure, use a mirror on a pole (or some other device) to check for sediment
or debris in the pipe connecting to the R-Tank.
R-TANK OPERATION, INSPECTION& MAINTENANCE
TECHNICALSTORMWATER MANAGEMENT
For more information or design assistance for our products, contact techinfo@acfwest.com.
If sediment or debris is observed in any of these structures, you should determine the depth of the
material. This is typically accomplished with a stadia rod, but you should determine the best way to
obtain the measurement.
All observations and measurements should be recorded on an Inspection Log kept on file. We’ve included a form you can use at the end of this guideline.
MaintenanceThe R-Tank System should be back-flushed once sediment accumulation has reached 6” or 15% of the
total system height. Use the chart below as a guideline to determine the point at which maintenance
is required on your system.
Before any maintenance is performed on your system, be sure to plug the outlet pipe to prevent contamination of the adjacent systems.
To back-flush the R-Tank, water is pumped into the system through the Maintenance Ports as rapidly
as possible. Water should be pumped into ALL Maintenance Ports. The turbulent action of the water
moving through the R-Tank will suspend sediments which may then be pumped out.
If your system includes an Outlet Structure, this will be the ideal location to pump contaminated water out of the system. However, removal of back-flush water may be accomplished through the
Maintenance Ports, as well.
For systems with large footprints that would require extensive volumes of water to properly flush the system, you should consider performing your maintenance within 24 hours of a rain event. Stormwater entering the system will aid in the suspension of sediments and reduce the volume of
water required to properly flush the system.
Once removed, sediment-laden water may be captured for disposal or pumped through a DirtbagTM (if permitted by the locality).
R-Tank Unit Height Max Sediment Dept
Mini 9.5” 1.5”
Single 17” 3”
Double 34” 5”
Triple 50” 6”
Quad 67” 6”
Pent 84” 6”
R-TANK OPERATION INSPECTION & MAINTENANCE
15540 Woodinville-Redmond Rd
Woodinville, Washington 98072
800-423-4567
www.acfwest.com
Step-By-Step Inspection & Maintenance Routine
1)Inspection
a.Inspection Port
i.Remove Cap
ii. Use flashlight to detect sediment deposits
iii. If present, measure sediment depth with stadia rod
iv. Record results on Maintenance Log
v.Replace Cap
b.Maintenance Port/s
i.Remove Cap
ii. Use flashlight to detect sediment deposits
iii.If present, measure sediment depth with stadia rod
iv.Record results on Maintenance Log
v. Replace Cap
vi.Repeat for ALL Maintenance Ports
c.Adjacent Manholes
i.Remove Cover
ii. Use flashlight to detect sediment deposits
iii. If present, measure sediment depth with stadia rod, accounting for depth
of sump (if present)
iv.Inspect pipes connecting to R-Tank
v.Record results on Maintenance Log
vi.Replace Cover
vii.Repeat for ALL Manholes that connect to the R-Tank
2)Maintenance
a.Plug system outlet to prevent discharge of back-flush water
b.Determine best location to pump out back-flush water
c.Remove Cap from Maintenance Port
d.Pump water as rapidly as possible (without over-topping port) into system until at least
1”
of water covers system bottom
e.Replace Cap
f.Repeat at ALL Maintenance Ports
g.Pump out back-flush water to complete back-flushing
h.Vacuum all adjacent structures and any other structures or stormwater pre-treatment
systems that require attention
i.Sediment-laden water may be captured for disposal or pumped through a DirtbagTM.
j.Replace any remaining Caps or Covers
k.Record the back-flushing event in your Maintenance Log with any relevant specifics
R-Tank Maintenance LogCompany ResponsibleSite Name:___________________________________________ for Maintenance:__________________________________________________Location:_____________________________________________System Owner:______________________________________ Contact:__________________________________________________________________ Phone Number:__________________________________________________________For more information or design assistance for our products, contact techinfo@acfwest.com.