HomeMy WebLinkAbout702 EAST MAIN DRAINAGE REPORT
702 EAST MAIN
DRAINAGE REPORT
23028
MFGR Designs
125 North Wallace Avenue
Bozeman, MT 59715
February 2024
702 EAST MAIN
FINAL DRAINAGE REPORT
BOZEMAN, MONTANA
CERTIFICATION
I hereby state that this Final Drainage Report has been prepared by me or under my supervision
and meets the standard of care and expertise which is usual and customary in this community of
professional engineers. The analysis has been prepared utilizing procedures and practices specified
by the City of Bozeman and within the standard accepted practices.
02/15/2024
Robert Egeberg, P.E. Date
P:23028_702_East_Main_Storm_Report 1 (02/15/24) DME/BE
February 15, 2024
Project No. 23028
DRAINAGE REPORT
702 EAST MAIN
BOZEMAN, MONTANA 59715
OVERVIEW NARRATIVE
The purpose of this drainage report is to present a summary of calculations to quantify the
stormwater runoff for the 702 East Main project located in Bozeman, Montana. All design
criteria and calculations were performed in accordance with The City of Bozeman Design
Standards and Specifications Policy, dated March 2004. The site stormwater improvements have
been designed with the intent to meet the current City of Bozeman drainage regulations for the
entire site to the extent feasible.
The site is located off East Main Street between Wallace Ave and North Broadway Ave and is
approximately 0.19 acres. The project area currently consists of a commercial building with a
gravel service lot. This project includes renovating the existing building and paving the existing
gravel service yard and driveway.
The impervious surface of the site will be increased with the addition of paved parking stalls.
The existing runoff currently sheet flows off property to the north and east and the design for
the expansion provides for a majority of onsite retention via proposed permeable pavers.
Stormwater facilities proposed for the development include permeable pavers and a retention
basin located in the north west section of the property.
The proposed site is divided into four (4) sub-basins. Calculations for each sub-basin and the
underground gravel retention pond are included in this submittal.
DESIGN APPROACH
The modified rational method was used to determine peak runoff rates and volumes. The
rational formula provided in The City of Bozeman Standard Specifications and Policy was used to
calculate the peak runoff rates on- site, time of concentration, rainfall intensities, etc. To be
conservative, we treated most watersheds as if they were predominately impervious cover,
therefore we assumed a time of concentration of five-minutes. For impervious surfaces, a runoff
coefficient of 0.95 was assumed, for pervious landscape surfaces, a runoff coefficient of 0.20 was
assumed, and for gravel areas, a runoff coefficient of 0.70 was assumed. Infiltration rates were
not considered in the sizing of the underground gravel retention pond.
P:23028_702_East_Main_Storm_Report 2 (02/15/24) DME/BE
Hydrology
The required retention volumes were sized for the 10-year, 2-hour storm with an intensity of
0.41 in/hr. Infiltration rates were not considered in the sizing of the underground gravel
retention system.
Existing Basins
The existing site includes approximately 3,666 SF (~.08 acres) of impervious surface, and 4,807
SF ( ~0.11 acres) of pervious surface. Existing Basin 1 includes half of the existing building roof
drain and the pervious landscape area below. Stormwater flows from the west to the east
towards the neighboring property in existing Basin 1. Existing Basin 2 is a pervious gravel area
located behind the existing building. In existing Basin 2 stormwater sheet flows from the west
to the east and from the north to the south and flows out onto the neighboring property.
Existing Basin 3 is an impervious area that includes roughly half of the existing buildings roof
drainage. This stormwater sheet flows off the roof and into existing basin 5, existing basin 6,
and existing basin 7. Existing Basin 4 is located to the south of the existing building and is a
pervious gravel area. Stormwater that falls within existing Basin 4 ponds and infiltrates into the
ground. Existing Basin 5 is a pervious gravel area. Stormwater within existing Basin 5 sheet
flows from east to west and flows out onto the neighboring property. Existing Basin 6 is a small
area that is comprised of both paved impervious surface and gravel pervious area. Stormwater
located within existing Basin 6 ponds and infiltrates into the ground. Existing Basin 7 is a paved
area located to the west of the existing building. Stormwater within existing Basin 7 sheet flows
over existing city sidewalk and onto Main Street where it is conveyed to a storm drain located
to the west of the property.
See Appendix A for the Existing Basins – Exhibit A. Runoff calculations for the existing basins
are shown in Appendix C.
Proposed Basins
For the following sections, please refer to Appendix B – Exhibit B of this report, which
graphically shows and labels the onsite watersheds as well as the proposed drainage facilities.
No percolation rates have been included in these calculations to be conservative. Storage
volume calculations used the 10-year, 2-hour design storm frequency for rainfall data, see
Appendix C.
Proposed Basin 1 includes approximately half of the existing building roof drain and the
proposed hardscape and landscape area directly to the east of the building. Proposed Basin 1
includes approximately 1,366 SF of impervious area and 458 SF of pervious area. Runoff
generated in Proposed Basin 1 sheetflows west to east off of the roof and west to east on the
ground directly to the east of the building. The stormwater then flows onto the neighboring
property. Proposed Basin 1 is not captured as its runoff remains the same as preexisting
conditions.
P:23028_702_East_Main_Storm_Report 3 (02/15/24) DME/BE
Proposed Basin 2 is located south east of the existing building. The area is comprised of a
proposed landscape area and new paving from the proposed parking lot. Proposed Basin 2
includes approximately 103 SF of impervious area and 295 SF of pervious area. Runoff
generated in Proposed Basin 2 sheetflows west to east off of the proposed surface and onto the
neighboring property. Proposed Basin 2 is not captured as its runoff remains the same as
preexisting conditions.
Proposed Basin 3 includes approximately half of the existing building roof drain. Proposed Basin
3 includes approximately 1,938 SF of impervious area and 0 SF of pervious area. Runoff
generated in Proposed Basin 3 sheetflows east to west off of the roof into a roof drain. Water
then sheetflows across the parking lot and onto permeable pavers where it infiltrates into the
ground below.
Proposed Basin 4 includes the proposed parking lot and proposed drive aisle. Proposed Basin 4
includes approximately 4,246 SF of impervious area and 69 SF of pervious area. Runoff
generated in Proposed Basin 4 sheetflows onto permeable pavers where it infiltrates into the
ground below.
Proposed Basins 1 and 2 are not captured as their runoff discharges in the same location as it
has historically and the proposed volume and peak discharge remains less that the existing
conditions. The amount of runoff leaving the site has been decreased. Proposed Basins 1 and 2
have a total area of 2,219.85 SF (0.05 acres) and have a drainage coefficient of 0.70. Proposed
Basins 1 and 2 require a total retention volume of 104.17 cf. The existing property required a
total retention volume of 461.58 cf, so the volume of runoff exiting the site has been reduced
by 357.41 cf.
Proposed Basins 3 and 4 consist of a total area of 6,251.91 SF (0.14 acres) and have a drainage
coefficient of 0.94. Proposed Basins 3 and 4 require a total retention volume of 396.92 cf.
Existing Basins 3, 4, 5, and 6 roughly had the same locations as Proposed Basins 3 and 4.
Existing Basins 3, 4, 5, and 6 had a total retention volume 160.38 cf. The required storage
volume is the post development retention volume minus existing retention volume. This gives a
required storage volume of 236.54 cf (396.92 cf -160.38 cf). The gravel trench located below
the permeable pavers has a total retention volume of 410.85 cf making the storm system
adequate to meet the storage requirements. The gravel trench beneath the permeable pavers is
3 ft wide by 83 ft long and has a depth of 5.5 ft. A void space of 0.3 was used when calculating
the available storage capacity within the 3 ft wide gravel section.
I. Calculations Basin 1
A = 0.03 acres + 0.01 acres = 0.04 acres
C’xA = (0.03*0.95)+(0.01*0.20) = 0.03 acres
C = 0.03 acres / 0.04 acres = 0.76
Q = 7200 x C x i x A
P:23028_702_East_Main_Storm_Report 4 (02/15/24) DME/BE
Where:
C = 0.76; i = 0.41 in/hr; A = 0.04 acres
Q = 93.63 cf
II. Calculations Basin II
A = 0.002 acres + 0.007 acres = 0.009 acres
C’xA = (0.002*0.95)+(0.007*0.20) = 0.004 acres
C = 0.004 acres / 0.009 acres = 0.39
Q = 7200 x C x i x A
Where:
C = 0.39; i = 0.41 in/hr; A = 0.009 acres
Q = 10.54 cf
III. Calculations Basin III
A = 0.04 acres + 0.00 acres = 0.04 acres
C’A = (0.04*0.95)+(0.00*0.20) = 0.04
C = 0.0422 acres / 0.0445 acres = 0.95
Q = 7200 x C x i x A
Where:
C = 0.95; i = 0.41 in/hr; A = 0.04 acres
Q = 124.07 cf
IV. Calculation Basin IV
A = 0.10 acres + 0.00 acres = 0.10 acres
C’xA = (0.10*0.95)+(0.00*0.20) = 0.09 acres
C = 0.09 acres / 0.10 acres = 0.94
Q = 7200 x C x i x A
Where:
C = 0.94; i = 0.41 in/hr; A = 0.10 acres
Q = 272.85 cf
HYDRAULICS
Storm Inlets and Storm Drains
There are no storm inlets or storm drains proposed within the scope of this project since it is
less than one (1) acre. However, we are retaining and infiltrating 79% of the drainage through
the proposed permeable pavers.
P:23028_702_East_Main_Storm_Report 5 (02/15/24) DME/BE
Water Quality
The project site is approximately 0.19 acres, so no water quality is required for this project.
Outlet Structures
There are no outlet structures proposed for this project. The majority of the runoff will be
captured and retained onsite. Storms larger than the design storm will overflow the permeable
pavers and drainage will flow into Main Street and not impact the building.
APPENDICES
Appendix A – Exhibit A (Existing Basins)
Appendix B – Exhibit B (Proposed Basins)
Appendix C – Rational Method Calculations
Appendix D – Surface Improvements O&M Plan
APPENDIX A EXHIBIT A (EXISTING BASINS)
APPENDIX B EXHIBIT B (PROPOSED BASINS)
APPENDIX C RATIONAL METHOD CALCULATIONS
Project: 702 East Main
Project #: 23028
Date: 11/10/2023
Design Storm Frequency =10 years
Discharge Rate, d =0.00 cfs
Input values for runoff coefficients from appropriate tables.
Area Area
Runoff
Coefficient
Frequency
Factor
Calculation
Value
A A/(43560 ft2/acre)C Cf C x Cf C' C' x A
(ft2)(Acres)=(C x Cf) < or = 1 (Acres)
3665.5424 0.084 0.95 1 0.95 0.95 0.08
4806.4991 0.110 0.70 1 0.70 0.70 0.08
1 0.00 0.00 0
1 0.00 0.00 0
1 0.00 0.00 0
8472.0415 0.1945 0.1572
Weighted Runoff Coefficient, Cwd SCjAj
SAj
Cwd x Cf x SAj =0.16
Where Cj is the adjusted runoff coefficient for surface type j
and Aj is the area of surface type j
Rainfall Rainfall Peak Flow
Duration, t Intensity, i
= Cwd x SAj x i
(min) (in/hr)(ft3/s)
1 9.16 1.44
5 3.22 0.51
10 2.05 0.32
15 1.58 0.25
20 1.31 0.21
25 1.13 0.18
30 1.00 0.16
35 0.91 0.14
40 0.83 0.13
45 0.77 0.12
50 0.72 0.11
55 0.68 0.11
60 0.64 0.10
75 0.55 0.09
90 0.49 0.08
105 0.44 0.07
120 0.41 0.06
150 0.35 0.06
180 0.31 0.05
360 0.20 0.03
720 0.13 0.02
1440 0.08 0.01
461.58 ft3 0.51 (ft3/s)
Impervious/Commercial Downtown
RATIONAL METHOD FOR RUNOFF CALCULATIONS
PRE-DEVELOPED OVERALL
Surface Type
Pervious/Gravel
Totals
= 0.8082 Cwd x Cf =0.81
Runoff Volume Discharge Volume Site Detention
=
= Cwd x SAj x i x t = d x t = Runoff Volume - Discharge Volume
(ft3) (ft
3) (ft
3)
86.40 0.00 86.40
151.76 0.00 151.76
193.43 0.00 193.43
222.93 0.00 222.93
246.54 0.00 246.54
266.57 0.00 266.57
284.13 0.00 284.13
299.88 0.00 299.88
314.23 0.00 314.23
327.46 0.00 327.46
339.76 0.00 339.76
351.28 0.00 351.28
362.15 0.00 362.15
391.56 0.00 391.56
417.36 0.00 417.36
440.50 0.00 440.50
461.58 0.00 461.58
499.07 0.00 499.07
531.96 0.00 531.96
678.01 0.00 678.01
864.16 0.00 864.16
1101.43 0.00 1101.43
=
Project: 702 East Main
Project #: 23028
Date: 11/10/2023
Design Storm Frequency =10 years
Discharge Rate, d =0.00 cfs
Input values for runoff coefficients from appropriate tables.
Area Area
Runoff
Coefficient
Frequency
Factor
Calculation
Value
A A/(43560 ft2/acre)C Cf C x Cf C' C' x A
(ft2)(Acres)=(C x Cf) < or = 1 (Acres)
1197.6460 0.027 0.95 1 0.95 0.95 0.03
625.4613 0.014 0.70 1 0.70 0.70 0.01
1 0.00 0.00 0
1 0.00 0.00 0
1 0.00 0.00 0
1823.1073 0.0419 0.0362
Weighted Runoff Coefficient, Cwd SCjAj
SAj
Cwd x Cf x SAj =0.04
Where Cj is the adjusted runoff coefficient for surface type j
and Aj is the area of surface type j
Rainfall Rainfall Peak Flow
Duration, t Intensity, i
= Cwd x SAj x i
(min) (in/hr)(ft3/s)
1 9.16 0.33
5 3.22 0.12
10 2.05 0.07
15 1.58 0.06
20 1.31 0.05
25 1.13 0.04
30 1.00 0.04
35 0.91 0.03
40 0.83 0.03
45 0.77 0.03
50 0.72 0.03
55 0.68 0.02
60 0.64 0.02
75 0.55 0.02
90 0.49 0.02
105 0.44 0.02
120 0.41 0.01
150 0.35 0.01
180 0.31 0.01
360 0.20 0.01
720 0.13 0.00
1440 0.08 0.00
106.22 ft3 0.12 (ft3/s)
198.86 0.00 198.86
253.46 0.00 253.46
122.41 0.00 122.41
156.02 0.00 156.02
106.22 0.00 106.22
114.85 0.00 114.85
96.04 0.00 96.04
101.37 0.00 101.37
83.34 0.00 83.34
90.11 0.00 90.11
78.19 0.00 78.19
80.84 0.00 80.84
72.31 0.00 72.31
75.35 0.00 75.35
65.38 0.00 65.38
69.01 0.00 69.01
56.73 0.00 56.73
61.34 0.00 61.34
44.51 0.00 44.51
51.30 0.00 51.30
19.88 0.00 19.88
34.92 0.00 34.92
= Cwd x SAj x i x t = d x t = Runoff Volume - Discharge Volume
(ft3) (ft
3) (ft
3)
= 0.8642 Cwd x Cf =0.86
Runoff Volume Discharge Volume Site Detention
Pervious/Gravel
Totals
=
RATIONAL METHOD FOR RUNOFF CALCULATIONS
PRE-DEVELOPED BASIN 1
Surface Type
Impervious/Commercial Downtown
=
Project: 702 East Main
Project #: 23028
Date: 11/10/2023
Design Storm Frequency =10 years
Discharge Rate, d =0.00 cfs
Input values for runoff coefficients from appropriate tables.
Area Area
Runoff
Coefficient
Frequency
Factor
Calculation
Value
A A/(43560 ft2/acre)C Cf C x Cf C' C' x A
(ft2)(Acres)=(C x Cf) < or = 1 (Acres)
0 0.000 0.95 1 0.95 0.95 0.00
1291.3671 0.030 0.70 1 0.70 0.70 0.02
1 0.00 0.00 0
1 0.00 0.00 0
1 0.00 0.00 0
1291.3671 0.0296 0.0208
Weighted Runoff Coefficient, Cwd SCjAj
SAj
Cwd x Cf x SAj =0.02
Where Cj is the adjusted runoff coefficient for surface type j
and Aj is the area of surface type j
Rainfall Rainfall Peak Flow
Duration, t Intensity, i
= Cwd x SAj x i
(min) (in/hr)(ft3/s)
1 9.16 0.19
5 3.22 0.07
10 2.05 0.04
15 1.58 0.03
20 1.31 0.03
25 1.13 0.02
30 1.00 0.02
35 0.91 0.02
40 0.83 0.02
45 0.77 0.02
50 0.72 0.01
55 0.68 0.01
60 0.64 0.01
75 0.55 0.01
90 0.49 0.01
105 0.44 0.01
120 0.41 0.01
150 0.35 0.01
180 0.31 0.01
360 0.20 0.00
720 0.13 0.00
1440 0.08 0.00
60.94 ft3 0.07 (ft3/s)
114.09 0.00 114.09
145.42 0.00 145.42
70.23 0.00 70.23
89.51 0.00 89.51
60.94 0.00 60.94
65.89 0.00 65.89
55.10 0.00 55.10
58.16 0.00 58.16
47.81 0.00 47.81
51.70 0.00 51.70
44.86 0.00 44.86
46.38 0.00 46.38
41.49 0.00 41.49
43.23 0.00 43.23
37.51 0.00 37.51
39.59 0.00 39.59
32.55 0.00 32.55
35.19 0.00 35.19
25.54 0.00 25.54
29.43 0.00 29.43
11.41 0.00 11.41
20.04 0.00 20.04
= Cwd x SAj x i x t = d x t = Runoff Volume - Discharge Volume
(ft3) (ft
3) (ft
3)
= 0.7000 Cwd x Cf =0.70
Runoff Volume Discharge Volume Site Detention
Pervious/Gravel
Totals
=
RATIONAL METHOD FOR RUNOFF CALCULATIONS
PRE-DEVELOPED BASIN 2
Surface Type
Impervious/Commercial Downtown
=
Project: 702 East Main
Project #: 23028
Date: 11/10/2023
Design Storm Frequency =10 years
Discharge Rate, d =0.00 cfs
Input values for runoff coefficients from appropriate tables.
Area Area
Runoff
Coefficient
Frequency
Factor
Calculation
Value
A A/(43560 ft2/acre)C Cf C x Cf C' C' x A
(ft2)(Acres)=(C x Cf) < or = 1 (Acres)
2067.4037 0.047 0.95 1 0.95 0.95 0.05
43.6701 0.001 0.70 1 0.70 0.70 0.00
1 0.00 0.00 0
1 0.00 0.00 0
1 0.00 0.00 0
2111.0738 0.0485 0.0458
Weighted Runoff Coefficient, Cwd SCjAj
SAj
Cwd x Cf x SAj =0.05
Where Cj is the adjusted runoff coefficient for surface type j
and Aj is the area of surface type j
Rainfall Rainfall Peak Flow
Duration, t Intensity, i
= Cwd x SAj x i
(min) (in/hr)(ft3/s)
1 9.16 0.42
5 3.22 0.15
10 2.05 0.09
15 1.58 0.07
20 1.31 0.06
25 1.13 0.05
30 1.00 0.05
35 0.91 0.04
40 0.83 0.04
45 0.77 0.04
50 0.72 0.03
55 0.68 0.03
60 0.64 0.03
75 0.55 0.03
90 0.49 0.02
105 0.44 0.02
120 0.41 0.02
150 0.35 0.02
180 0.31 0.01
360 0.20 0.01
720 0.13 0.01
1440 0.08 0.00
134.47 ft3 0.15 (ft3/s)
251.75 0.00 251.75
320.87 0.00 320.87
154.97 0.00 154.97
197.52 0.00 197.52
134.47 0.00 134.47
145.39 0.00 145.39
121.59 0.00 121.59
128.33 0.00 128.33
105.50 0.00 105.50
114.07 0.00 114.07
98.98 0.00 98.98
102.34 0.00 102.34
91.54 0.00 91.54
95.39 0.00 95.39
82.77 0.00 82.77
87.36 0.00 87.36
71.82 0.00 71.82
77.66 0.00 77.66
56.35 0.00 56.35
64.94 0.00 64.94
25.17 0.00 25.17
44.21 0.00 44.21
= Cwd x SAj x i x t = d x t = Runoff Volume - Discharge Volume
(ft3) (ft
3) (ft
3)
= 0.9448 Cwd x Cf =0.94
Runoff Volume Discharge Volume Site Detention
Pervious/Gravel
Totals
=
RATIONAL METHOD FOR RUNOFF CALCULATIONS
PRE-DEVELOPED BASIN 3
Surface Type
Impervious/Commercial Downtown
=
Project: 702 East Main
Project #: 23028
Date: 11/10/2023
Design Storm Frequency =10 years
Discharge Rate, d =0.00 cfs
Input values for runoff coefficients from appropriate tables.
Area Area
Runoff
Coefficient
Frequency
Factor
Calculation
Value
A A/(43560 ft2/acre)C Cf C x Cf C' C' x A
(ft2)(Acres)=(C x Cf) < or = 1 (Acres)
0 0.000 0.95 1 0.95 0.95 0.00
1501.8950 0.034 0.70 1 0.70 0.70 0.02
1 0.00 0.00 0
1 0.00 0.00 0
1 0.00 0.00 0
1501.895 0.0345 0.0241
Weighted Runoff Coefficient, Cwd SCjAj
SAj
Cwd x Cf x SAj =0.02
Where Cj is the adjusted runoff coefficient for surface type j
and Aj is the area of surface type j
Rainfall Rainfall Peak Flow
Duration, t Intensity, i
= Cwd x SAj x i
(min) (in/hr)(ft3/s)
1 9.16 0.22
5 3.22 0.08
10 2.05 0.05
15 1.58 0.04
20 1.31 0.03
25 1.13 0.03
30 1.00 0.02
35 0.91 0.02
40 0.83 0.02
45 0.77 0.02
50 0.72 0.02
55 0.68 0.02
60 0.64 0.02
75 0.55 0.01
90 0.49 0.01
105 0.44 0.01
120 0.41 0.01
150 0.35 0.01
180 0.31 0.01
360 0.20 0.00
720 0.13 0.00
1440 0.08 0.00
70.87 ft3 0.08 (ft3/s)
132.69 0.00 132.69
169.12 0.00 169.12
81.68 0.00 81.68
104.11 0.00 104.11
70.87 0.00 70.87
76.63 0.00 76.63
64.09 0.00 64.09
67.64 0.00 67.64
55.61 0.00 55.61
60.12 0.00 60.12
52.17 0.00 52.17
53.94 0.00 53.94
48.25 0.00 48.25
50.28 0.00 50.28
43.63 0.00 43.63
46.05 0.00 46.05
37.86 0.00 37.86
40.93 0.00 40.93
29.70 0.00 29.70
34.23 0.00 34.23
13.27 0.00 13.27
23.30 0.00 23.30
= Cwd x SAj x i x t = d x t = Runoff Volume - Discharge Volume
(ft3) (ft
3) (ft
3)
= 0.7000 Cwd x Cf =0.70
Runoff Volume Discharge Volume Site Detention
Pervious/Gravel
Totals
=
RATIONAL METHOD FOR RUNOFF CALCULATIONS
PRE-DEVELOPED BASIN 4
Surface Type
Impervious/Commercial Downtown
=
Project: 702 East Main
Project #: 23028
Date: 11/10/2023
Design Storm Frequency =10 years
Discharge Rate, d =0.00 cfs
Input values for runoff coefficients from appropriate tables.
Area Area
Runoff
Coefficient
Frequency
Factor
Calculation
Value
A A/(43560 ft2/acre)C Cf C x Cf C' C' x A
(ft2)(Acres)=(C x Cf) < or = 1 (Acres)
0 0.000 0.95 1 0.95 0.95 0.00
1244.7302 0.029 0.70 1 0.70 0.70 0.02
1 0.00 0.00 0
1 0.00 0.00 0
1 0.00 0.00 0
1244.7302 0.0286 0.0200
Weighted Runoff Coefficient, Cwd SCjAj
SAj
Cwd x Cf x SAj =0.02
Where Cj is the adjusted runoff coefficient for surface type j
and Aj is the area of surface type j
Rainfall Rainfall Peak Flow
Duration, t Intensity, i
= Cwd x SAj x i
(min) (in/hr)(ft3/s)
1 9.16 0.18
5 3.22 0.06
10 2.05 0.04
15 1.58 0.03
20 1.31 0.03
25 1.13 0.02
30 1.00 0.02
35 0.91 0.02
40 0.83 0.02
45 0.77 0.02
50 0.72 0.01
55 0.68 0.01
60 0.64 0.01
75 0.55 0.01
90 0.49 0.01
105 0.44 0.01
120 0.41 0.01
150 0.35 0.01
180 0.31 0.01
360 0.20 0.00
720 0.13 0.00
1440 0.08 0.00
58.74 ft3 0.06 (ft3/s)
109.97 0.00 109.97
140.17 0.00 140.17
67.70 0.00 67.70
86.28 0.00 86.28
58.74 0.00 58.74
63.51 0.00 63.51
53.11 0.00 53.11
56.06 0.00 56.06
46.09 0.00 46.09
49.83 0.00 49.83
43.24 0.00 43.24
44.70 0.00 44.70
39.99 0.00 39.99
41.67 0.00 41.67
36.16 0.00 36.16
38.16 0.00 38.16
31.37 0.00 31.37
33.92 0.00 33.92
24.62 0.00 24.62
28.37 0.00 28.37
11.00 0.00 11.00
19.31 0.00 19.31
= Cwd x SAj x i x t = d x t = Runoff Volume - Discharge Volume
(ft3) (ft
3) (ft
3)
= 0.7000 Cwd x Cf =0.70
Runoff Volume Discharge Volume Site Detention
Pervious/Gravel
Totals
=
RATIONAL METHOD FOR RUNOFF CALCULATIONS
PRE-DEVELOPED BASIN 5
Surface Type
Impervious/Commercial Downtown
=
Project: 702 East Main
Project #: 23028
Date: 11/10/2023
Design Storm Frequency =10 years
Discharge Rate, d =0.00 cfs
Input values for runoff coefficients from appropriate tables.
Area Area
Runoff
Coefficient
Frequency
Factor
Calculation
Value
A A/(43560 ft2/acre)C Cf C x Cf C' C' x A
(ft2)(Acres)=(C x Cf) < or = 1 (Acres)
33.2343 0.001 0.95 1 0.95 0.95 0.00
79.7709 0.002 0.70 1 0.70 0.70 0.00
1 0.00 0.00 0
1 0.00 0.00 0
1 0.00 0.00 0
113.0052 0.0026 0.0020
Weighted Runoff Coefficient, Cwd SCjAj
SAj
Cwd x Cf x SAj =0.00
Where Cj is the adjusted runoff coefficient for surface type j
and Aj is the area of surface type j
Rainfall Rainfall Peak Flow
Duration, t Intensity, i
= Cwd x SAj x i
(min) (in/hr)(ft3/s)
1 9.16 0.02
5 3.22 0.01
10 2.05 0.00
15 1.58 0.00
20 1.31 0.00
25 1.13 0.00
30 1.00 0.00
35 0.91 0.00
40 0.83 0.00
45 0.77 0.00
50 0.72 0.00
55 0.68 0.00
60 0.64 0.00
75 0.55 0.00
90 0.49 0.00
105 0.44 0.00
120 0.41 0.00
150 0.35 0.00
180 0.31 0.00
360 0.20 0.00
720 0.13 0.00
1440 0.08 0.00
5.89 ft3 0.01 (ft3/s)
11.03 0.00 11.03
14.06 0.00 14.06
6.79 0.00 6.79
8.66 0.00 8.66
5.89 0.00 5.89
6.37 0.00 6.37
5.33 0.00 5.33
5.62 0.00 5.62
4.62 0.00 4.62
5.00 0.00 5.00
4.34 0.00 4.34
4.48 0.00 4.48
4.01 0.00 4.01
4.18 0.00 4.18
3.63 0.00 3.63
3.83 0.00 3.83
3.15 0.00 3.15
3.40 0.00 3.40
2.47 0.00 2.47
2.85 0.00 2.85
1.10 0.00 1.10
1.94 0.00 1.94
= Cwd x SAj x i x t = d x t = Runoff Volume - Discharge Volume
(ft3) (ft
3) (ft
3)
= 0.7735 Cwd x Cf =0.77
Runoff Volume Discharge Volume Site Detention
Pervious/Gravel
Totals
=
RATIONAL METHOD FOR RUNOFF CALCULATIONS
PRE-DEVELOPED BASIN 6
Surface Type
Impervious/Commercial Downtown
=
Project: 702 East Main
Project #: 23028
Date: 11/10/2023
Design Storm Frequency =10 years
Discharge Rate, d =0.00 cfs
Input values for runoff coefficients from appropriate tables.
Area Area
Runoff
Coefficient
Frequency
Factor
Calculation
Value
A A/(43560 ft2/acre)C Cf C x Cf C' C' x A
(ft2)(Acres)=(C x Cf) < or = 1 (Acres)
388.4479 0.009 0.95 1 0.95 0.95 0.01
0 0.000 0.70 1 0.70 0.70 0.00
1 0.00 0.00 0
1 0.00 0.00 0
1 0.00 0.00 0
388.4479 0.0089 0.0085
Weighted Runoff Coefficient, Cwd SCjAj
SAj
Cwd x Cf x SAj =0.01
Where Cj is the adjusted runoff coefficient for surface type j
and Aj is the area of surface type j
Rainfall Rainfall Peak Flow
Duration, t Intensity, i
= Cwd x SAj x i
(min) (in/hr)(ft3/s)
1 9.16 0.08
5 3.22 0.03
10 2.05 0.02
15 1.58 0.01
20 1.31 0.01
25 1.13 0.01
30 1.00 0.01
35 0.91 0.01
40 0.83 0.01
45 0.77 0.01
50 0.72 0.01
55 0.68 0.01
60 0.64 0.01
75 0.55 0.00
90 0.49 0.00
105 0.44 0.00
120 0.41 0.00
150 0.35 0.00
180 0.31 0.00
360 0.20 0.00
720 0.13 0.00
1440 0.08 0.00
24.88 ft3 0.03 (ft3/s)
46.58 0.00 46.58
59.36 0.00 59.36
28.67 0.00 28.67
36.54 0.00 36.54
24.88 0.00 24.88
26.90 0.00 26.90
22.49 0.00 22.49
23.74 0.00 23.74
19.52 0.00 19.52
21.10 0.00 21.10
18.31 0.00 18.31
18.93 0.00 18.93
16.94 0.00 16.94
17.65 0.00 17.65
15.31 0.00 15.31
16.16 0.00 16.16
13.29 0.00 13.29
14.37 0.00 14.37
10.43 0.00 10.43
12.02 0.00 12.02
4.66 0.00 4.66
8.18 0.00 8.18
= Cwd x SAj x i x t = d x t = Runoff Volume - Discharge Volume
(ft3) (ft
3) (ft
3)
= 0.9500 Cwd x Cf =0.95
Runoff Volume Discharge Volume Site Detention
Pervious/Gravel
Totals
=
RATIONAL METHOD FOR RUNOFF CALCULATIONS
PRE-DEVELOPED BASIN 7
Surface Type
Impervious/Commercial Downtown
=
Project: 702 East Main
Project #: 23028
Date: 11/10/2023
Design Storm Frequency =10 years
Discharge Rate, d =0.00 cfs
Input values for runoff coefficients from appropriate tables.
Area Area
Runoff
Coefficient
Frequency
Factor
Calculation
Value
A A/(43560 ft2/acre)C Cf C x Cf C' C' x A
(ft2)(Acres)=(C x Cf) < or = 1 (Acres)
1468.396 0.034 0.95 1 0.95 0.95 0.03
751.4511 0.017 0.20 1 0.20 0.20 0.00
1 0.00 0.00 0
1 0.00 0.00 0
1 0.00 0.00 0
2219.8471 0.0510 0.0355
Weighted Runoff Coefficient, Cwd SCjAj
SAj
Cwd x Cf x SAj =0.04
Where Cj is the adjusted runoff coefficient for surface type j
and Aj is the area of surface type j
Rainfall Rainfall Peak Flow
Duration, t Intensity, i
= Cwd x SAj x i
(min) (in/hr)(ft3/s)
1 9.16 0.33
5 3.22 0.11
10 2.05 0.07
15 1.58 0.06
20 1.31 0.05
25 1.13 0.04
30 1.00 0.04
35 0.91 0.03
40 0.83 0.03
45 0.77 0.03
50 0.72 0.03
55 0.68 0.02
60 0.64 0.02
75 0.55 0.02
90 0.49 0.02
105 0.44 0.02
120 0.41 0.01
150 0.35 0.01
180 0.31 0.01
360 0.20 0.01
720 0.13 0.00
1440 0.08 0.00
104.17 ft3 0.11 (ft3/s)
195.03 0.00 195.03
248.58 0.00 248.58
120.06 0.00 120.06
153.02 0.00 153.02
104.17 0.00 104.17
112.64 0.00 112.64
94.20 0.00 94.20
99.42 0.00 99.42
81.73 0.00 81.73
88.37 0.00 88.37
76.68 0.00 76.68
79.28 0.00 79.28
70.92 0.00 70.92
73.90 0.00 73.90
64.13 0.00 64.13
67.68 0.00 67.68
55.64 0.00 55.64
60.16 0.00 60.16
43.66 0.00 43.66
50.31 0.00 50.31
19.50 0.00 19.50
34.25 0.00 34.25
= Cwd x SAj x i x t = d x t = Runoff Volume - Discharge Volume
(ft3) (ft
3) (ft
3)
= 0.6961 Cwd x Cf =0.70
Runoff Volume Discharge Volume Site Detention
=
Pervious/Landscape
Totals
Impervious/Commercial Downtown
RATIONAL METHOD FOR RUNOFF CALCULATIONS
POST-DEVELOPED BASINS 1 AND 2
Surface Type
=
Project: 702 East Main
Project #: 23028
Date: 11/10/2023
Design Storm Frequency =10 years
Discharge Rate, d =0.00 cfs
Input values for runoff coefficients from appropriate tables.
Area Area
Runoff
Coefficient
Frequency
Factor
Calculation
Value
A A/(43560 ft2/acre)C Cf C x Cf C' C' x A
(ft2)(Acres)=(C x Cf) < or = 1 (Acres)
6183.0932 0.142 0.95 1 0.95 0.95 0.13
68.8205 0.002 0.20 1 0.20 0.20 0.00
1 0.00 0.00 0
1 0.00 0.00 0
1 0.00 0.00 0
6251.9137 0.1435 0.1352
Weighted Runoff Coefficient, Cwd SCjAj
SAj
Cwd x Cf x SAj =0.14
Where Cj is the adjusted runoff coefficient for surface type j
and Aj is the area of surface type j
Rainfall Rainfall Peak Flow
Duration, t Intensity, i
= Cwd x SAj x i
(min) (in/hr)(ft3/s)
1 9.16 1.24
5 3.22 0.44
10 2.05 0.28
15 1.58 0.21
20 1.31 0.18
25 1.13 0.15
30 1.00 0.14
35 0.91 0.12
40 0.83 0.11
45 0.77 0.10
50 0.72 0.10
55 0.68 0.09
60 0.64 0.09
75 0.55 0.07
90 0.49 0.07
105 0.44 0.06
120 0.41 0.06
150 0.35 0.05
180 0.31 0.04
360 0.20 0.03
720 0.13 0.02
1440 0.08 0.01
396.92 ft3 0.44 (ft3/s)
Impervious/Commercial Downtown
RATIONAL METHOD FOR RUNOFF CALCULATIONS
POST-DEVELOPED BASINS 3 AND 4
Surface Type
Pervious/Landscape
Totals
= 0.9417 Cwd x Cf =0.94
Runoff Volume Discharge Volume Site Detention
=
= Cwd x SAj x i x t = d x t = Runoff Volume - Discharge Volume
(ft3) (ft
3) (ft
3)
74.30 0.00 74.30
130.50 0.00 130.50
166.34 0.00 166.34
191.70 0.00 191.70
212.01 0.00 212.01
229.23 0.00 229.23
244.33 0.00 244.33
257.88 0.00 257.88
270.21 0.00 270.21
281.59 0.00 281.59
292.16 0.00 292.16
302.07 0.00 302.07
311.42 0.00 311.42
336.71 0.00 336.71
358.90 0.00 358.90
378.79 0.00 378.79
396.92 0.00 396.92
429.16 0.00 429.16
457.44 0.00 457.44
583.03 0.00 583.03
743.11 0.00 743.11
947.14 0.00 947.14
=
Project: 702 East Main
Project #: 23028
Date: 11/10/2023
Design Storm Frequency =10 years
Discharge Rate, d =0.00 cfs
Input values for runoff coefficients from appropriate tables.
Area Area
Runoff
Coefficient
Frequency
Factor
Calculation
Value
A A/(43560 ft2/acre)C Cf C x Cf C' C' x A
(ft2)(Acres)=(C x Cf) < or = 1 (Acres)
1365.7447 0.031 0.95 1 0.95 0.95 0.03
457.3626 0.010 0.20 1 0.20 0.20 0.00
1 0.00 0.00 0
1 0.00 0.00 0
1 0.00 0.00 0
1823.1073 0.0419 0.0319
Weighted Runoff Coefficient, Cwd SCjAj
SAj
Cwd x Cf x SAj =0.03
Where Cj is the adjusted runoff coefficient for surface type j
and Aj is the area of surface type j
Rainfall Rainfall Peak Flow
Duration, t Intensity, i
= Cwd x SAj x i
(min) (in/hr)(ft3/s)
1 9.16 0.29
5 3.22 0.10
10 2.05 0.07
15 1.58 0.05
20 1.31 0.04
25 1.13 0.04
30 1.00 0.03
35 0.91 0.03
40 0.83 0.03
45 0.77 0.02
50 0.72 0.02
55 0.68 0.02
60 0.64 0.02
75 0.55 0.02
90 0.49 0.02
105 0.44 0.01
120 0.41 0.01
150 0.35 0.01
180 0.31 0.01
360 0.20 0.01
720 0.13 0.00
1440 0.08 0.00
93.63 ft3 0.10 (ft3/s)
175.30 0.00 175.30
223.43 0.00 223.43
107.91 0.00 107.91
137.54 0.00 137.54
93.63 0.00 93.63
101.24 0.00 101.24
84.67 0.00 84.67
89.36 0.00 89.36
73.46 0.00 73.46
79.43 0.00 79.43
68.92 0.00 68.92
71.26 0.00 71.26
63.74 0.00 63.74
66.43 0.00 66.43
57.64 0.00 57.64
60.83 0.00 60.83
50.01 0.00 50.01
54.08 0.00 54.08
39.24 0.00 39.24
45.22 0.00 45.22
17.53 0.00 17.53
30.79 0.00 30.79
= Cwd x SAj x i x t = d x t = Runoff Volume - Discharge Volume
(ft3) (ft
3) (ft
3)
= 0.7618 Cwd x Cf =0.76
Runoff Volume Discharge Volume Site Detention
=
Pervious/Landscape
Totals
Impervious/Commercial Downtown
RATIONAL METHOD FOR RUNOFF CALCULATIONS
POST-DEVELOPED BASIN 1
Surface Type
=
Project: 702 East Main
Project #: 23028
Date: 11/10/2023
Design Storm Frequency =10 years
Discharge Rate, d =0.00 cfs
Input values for runoff coefficients from appropriate tables.
Area Area
Runoff
Coefficient
Frequency
Factor
Calculation
Value
A A/(43560 ft2/acre)C Cf C x Cf C' C' x A
(ft2)(Acres)=(C x Cf) < or = 1 (Acres)
102.6513 0.002 0.95 1 0.95 0.95 0.00
294.0885 0.007 0.20 1 0.20 0.20 0.00
1 0.00 0.00 0
1 0.00 0.00 0
1 0.00 0.00 0
396.7398 0.0091 0.0036
Weighted Runoff Coefficient, Cwd SCjAj
SAj
Cwd x Cf x SAj =0.00
Where Cj is the adjusted runoff coefficient for surface type j
and Aj is the area of surface type j
Rainfall Rainfall Peak Flow
Duration, t Intensity, i
= Cwd x SAj x i
(min) (in/hr)(ft3/s)
1 9.16 0.03
5 3.22 0.01
10 2.05 0.01
15 1.58 0.01
20 1.31 0.00
25 1.13 0.00
30 1.00 0.00
35 0.91 0.00
40 0.83 0.00
45 0.77 0.00
50 0.72 0.00
55 0.68 0.00
60 0.64 0.00
75 0.55 0.00
90 0.49 0.00
105 0.44 0.00
120 0.41 0.00
150 0.35 0.00
180 0.31 0.00
360 0.20 0.00
720 0.13 0.00
1440 0.08 0.00
10.54 ft3 0.01 (ft3/s)
19.73 0.00 19.73
25.15 0.00 25.15
12.15 0.00 12.15
15.48 0.00 15.48
10.54 0.00 10.54
11.40 0.00 11.40
9.53 0.00 9.53
10.06 0.00 10.06
8.27 0.00 8.27
8.94 0.00 8.94
7.76 0.00 7.76
8.02 0.00 8.02
7.18 0.00 7.18
7.48 0.00 7.48
6.49 0.00 6.49
6.85 0.00 6.85
5.63 0.00 5.63
6.09 0.00 6.09
4.42 0.00 4.42
5.09 0.00 5.09
1.97 0.00 1.97
3.47 0.00 3.47
= Cwd x SAj x i x t = d x t = Runoff Volume - Discharge Volume
(ft3) (ft
3) (ft
3)
= 0.3941 Cwd x Cf =0.39
Runoff Volume Discharge Volume Site Detention
=
Pervious/Landscape
Totals
Impervious/Commercial Downtown
RATIONAL METHOD FOR RUNOFF CALCULATIONS
POST-DEVELOPED BASIN 2
Surface Type
=
Project: 702 East Main
Project #: 23028
Date: 11/10/2023
Design Storm Frequency =10 years
Discharge Rate, d =0.00 cfs
Input values for runoff coefficients from appropriate tables.
Area Area
Runoff
Coefficient
Frequency
Factor
Calculation
Value
A A/(43560 ft2/acre)C Cf C x Cf C' C' x A
(ft2)(Acres)=(C x Cf) < or = 1 (Acres)
1937.229 0.044 0.95 1 0.95 0.95 0.04
0 0.000 0.20 1 0.20 0.20 0.00
1 0.00 0.00 0
1 0.00 0.00 0
1 0.00 0.00 0
1937.229 0.0445 0.0422
Weighted Runoff Coefficient, Cwd SCjAj
SAj
Cwd x Cf x SAj =0.04
Where Cj is the adjusted runoff coefficient for surface type j
and Aj is the area of surface type j
Rainfall Rainfall Peak Flow
Duration, t Intensity, i
= Cwd x SAj x i
(min) (in/hr)(ft3/s)
1 9.16 0.39
5 3.22 0.14
10 2.05 0.09
15 1.58 0.07
20 1.31 0.06
25 1.13 0.05
30 1.00 0.04
35 0.91 0.04
40 0.83 0.04
45 0.77 0.03
50 0.72 0.03
55 0.68 0.03
60 0.64 0.03
75 0.55 0.02
90 0.49 0.02
105 0.44 0.02
120 0.41 0.02
150 0.35 0.01
180 0.31 0.01
360 0.20 0.01
720 0.13 0.01
1440 0.08 0.00
124.07 ft3 0.14 (ft3/s)
232.28 0.00 232.28
296.06 0.00 296.06
142.99 0.00 142.99
182.24 0.00 182.24
124.07 0.00 124.07
134.15 0.00 134.15
112.18 0.00 112.18
118.40 0.00 118.40
97.34 0.00 97.34
105.25 0.00 105.25
91.32 0.00 91.32
94.42 0.00 94.42
84.46 0.00 84.46
88.02 0.00 88.02
76.37 0.00 76.37
80.61 0.00 80.61
66.27 0.00 66.27
71.65 0.00 71.65
51.99 0.00 51.99
59.92 0.00 59.92
23.22 0.00 23.22
40.79 0.00 40.79
= Cwd x SAj x i x t = d x t = Runoff Volume - Discharge Volume
(ft3) (ft
3) (ft
3)
= 0.9500 Cwd x Cf =0.95
Runoff Volume Discharge Volume Site Detention
=
Pervious/Landscape
Totals
Impervious/Commercial Downtown
RATIONAL METHOD FOR RUNOFF CALCULATIONS
POST-DEVELOPED BASIN 3
Surface Type
=
Project: 702 East Main
Project #: 23028
Date: 11/10/2023
Design Storm Frequency =10 years
Discharge Rate, d =0.00 cfs
Input values for runoff coefficients from appropriate tables.
Area Area
Runoff
Coefficient
Frequency
Factor
Calculation
Value
A A/(43560 ft2/acre)C Cf C x Cf C' C' x A
(ft2)(Acres)=(C x Cf) < or = 1 (Acres)
4245.8642 0.097 0.95 1 0.95 0.95 0.09
68.8205 0.002 0.20 1 0.20 0.20 0.00
1 0.00 0.00 0
1 0.00 0.00 0
1 0.00 0.00 0
4314.6847 0.0991 0.0929
Weighted Runoff Coefficient, Cwd SCjAj
SAj
Cwd x Cf x SAj =0.09
Where Cj is the adjusted runoff coefficient for surface type j
and Aj is the area of surface type j
Rainfall Rainfall Peak Flow
Duration, t Intensity, i
= Cwd x SAj x i
(min) (in/hr)(ft3/s)
1 9.16 0.85
5 3.22 0.30
10 2.05 0.19
15 1.58 0.15
20 1.31 0.12
25 1.13 0.11
30 1.00 0.09
35 0.91 0.08
40 0.83 0.08
45 0.77 0.07
50 0.72 0.07
55 0.68 0.06
60 0.64 0.06
75 0.55 0.05
90 0.49 0.05
105 0.44 0.04
120 0.41 0.04
150 0.35 0.03
180 0.31 0.03
360 0.20 0.02
720 0.13 0.01
1440 0.08 0.01
272.85 ft3 0.30 (ft3/s)
510.83 0.00 510.83
651.09 0.00 651.09
314.45 0.00 314.45
400.79 0.00 400.79
272.85 0.00 272.85
295.01 0.00 295.01
246.72 0.00 246.72
260.39 0.00 260.39
214.07 0.00 214.07
231.46 0.00 231.46
200.84 0.00 200.84
207.65 0.00 207.65
185.75 0.00 185.75
193.57 0.00 193.57
167.96 0.00 167.96
177.27 0.00 177.27
145.74 0.00 145.74
157.58 0.00 157.58
114.34 0.00 114.34
131.78 0.00 131.78
51.08 0.00 51.08
89.71 0.00 89.71
= Cwd x SAj x i x t = d x t = Runoff Volume - Discharge Volume
(ft3) (ft
3) (ft
3)
= 0.9380 Cwd x Cf =0.94
Runoff Volume Discharge Volume Site Detention
=
Pervious/Landscape
Totals
Impervious/Commercial Downtown
RATIONAL METHOD FOR RUNOFF CALCULATIONS
POST-DEVELOPED SUB BASIN 4
Surface Type
=
APPENDIX D SURFACE IMPROVEMENTS O&M PLAN
February 15, 2024
Project No. 23028
STORM DRAINAGE FACILITY MAINTENANCE PLAN
FOR
702 EAST MAIN
BOZEMAN, MONTANA
OVERVIEW NARRATIVE
The purpose of this maintenance plan is to outline the necessary details related to ownership,
responsibility, and cleaning schedule for the storm drainage facilities for the 702 East Main
project. This plan has been completed in accordance with The City of Bozeman Design Standards
and Specifications Policy, dated March 2004. The site stormwater improvements have been
designed with the intent to meet the current City of Bozeman drainage regulations for the
entire site to the extent feasible.
Specific site information and criteria are described below:
OWNERSHIP OF FACILITIES
702 East Main will own all stormwater facilities which includes the permeable pavers, gravel
retention basin, and piping within the site boundary.
Inspection
• Inspect the permeable pavement, noting areas of standing water or significant
accumulation of joint debris.
• If joins are excessively filled with debris or sediment, a surface infiltration test may be
performed per Table 2.1A to determine capabilities of the system.
Cleaning
• Maintenance shall be performed when either:
o The surface infiltration rates of more than 75% of the surface area fall
below 10% of the rate required per Table 2.1a.
o Surface ponding remains for 24 hours in an area larger than 10 square
feet.
o Other desired maintenance at the Owners discretion to optimize
performance.
P: HAMPTON_INN_O&M 2 (02/15/24) DME/BE
• Maintenance shall be performed with a vacuum device, not a mechanical sweeper, to
remove accumulated debris from joints. This may be accomplished with smaller hand-
held devices or with vacuum trucks such as the Elgin Whirlwind. Adjust device settings
to avoid movement or lifting of block, or removal of the base stone underneath the
blocks at all times.
TABLE 2.1A
PROPERTY DESCRIPTION VALUE
Dimensions Length x Width x Height 11.75” x 13.70” x 4.5” (+/-
1/8”)
Block Weight Pounds 44 lbs Minimum
Loading Capacity Traffic Rating HS-20 / HS-25
Open Joint Width Inches 0.25” (+/- 0.02”)
Joint Filler Between Blocks Material Used NONE ALLOWED 1
Post-Installation, Field-Verified
Surface Infiltration Rate 3
ASTM C-1701 / C-1701-M09 /
ASTM C-1781 / C-140
1,000 inches / hour average
(Minimum 3 tests)
Compressive Strength ASTM D-6684 / C-140 4,000 psi (average)
3,500 psi (minimum)
Freeze / Thaw Resistance 2 ASTM C-67 / C-1645 / C-936
NOTE 1: No filler material is allowed to be used between the blocks. Use ONLY blocks that
do not require stabilizing stone/sand between units.
NOTE 2: Testing by the National Concrete Masonry Association (NCMA) will be made
available for freeze/thaw and abrasion resistance upon request.
NOTE 3: The completed permeable pavement system must be tested in-situ after installation
and will only be accepted when required performance value shown in Table 2.1A has been
documented by a third party. Final test report must be submitted to the Owner prior to
acceptance.
RESPONSIBLE PARTY
702 East Main will be responsible for the inspection and maintenance of all stormwater facilities
located within the project limits
I agree to the above operation, maintenance and replacement schedule detailed above.
Signature: __________________________________________
702 East Main Representative