HomeMy WebLinkAbout20 - Design Report - Aspen Street (URD) - Drainage
BOZEMAN URBAN RENEWAL DISTRICT: ASPEN STREET
18098.06
City of Bozeman
20 East Olive St
Bozeman, Montana 59771
January 2020
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January 20, 2020
Project No. 18086.06
FINAL DRAINAGE REPORT
FOR
BOZEMAN URBAN RENEWAL DISTRICT: ASPEN STREET
BOZEMAN, MONTANA
A. INTRODUCTION
The purpose of this drainage report is to summarize the storm drainage improvements required for
the redevelopment of a portion of Aspen Street in Bozeman, Montana. All design criteria and
calculations will be reviewed by the City of Bozeman.
Specific site information and criteria are described below:
1. Development Location
a. Site Location: The redevelopment area includes Aspen St. from N. 7th Ave to N. 5th
Ave. In addition, the east side of N. 5th Ave including areas about one block to the
north and south of Aspen St. are planned to include new angled parking.
b. Adjacent Developments: Zoning in the area is generally B-2M (Community business
district-mixed), with an area to the east being a park zoned PLI (Public lands and
institutions). The northwestern quarter of the development area is included in the
Aspen Crossing Master Site Plan.
2. Description of Property
a. Total Contributing Area: The total estimated drainage area is 4.44 acres. The area is
currently developed, and includes commercial downtown space and streets. The street
slopes to the east at three percent or less. The Aspen St. redevelopment will replace
some existing asphalt or concrete paved area with pervious pavers and add pervious
landscaping features including trees and planter boxes. Offsite run-on area includes
the east half of N. 7th Ave from Peach St. to Aspen St. (about 1.1 acres) and parts of
the commercial properties to the south (2.8 acres).
b. Ground Cover: The site is mainly composed of roofs or paved area with little pervious
area. Impervious area will decrease with this project development. Existing
landscaping is generally grass with a few trees. Site soils are generally composed of
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hydrologic soil group C. A composite Rational Method runoff coefficient of 0.81 has
been used for the redeveloped site condition.
c. Existing and Future Land Uses: Zoning and land usage will not change with this
redevelopment.
d. Topographic Features, Steepness, and Slopes: The land generally slopes towards
the east to N. 5th Ave then to the north along N. 5th Ave, with slopes ranging from 0.5
to 3.5 percent.
e. Major Drainage Ways and Receiving Channels: There are no major drainage ways
in the immediate vicinity of the site.
f. Existing Drainage Facilities: Currently, there are no existing underground drainage
facilities present. There is curb and gutter along N. 7th Ave, N. 5th Ave, and Aspen St.,
but no storm drain inlets.
g. Flood Hazard Zone: The site is not within any flood hazard zones. Appendix A
shows the flood map for the project location.
h. Geological Features: The site does not contain any notable geological features.
3. Proposed Project Description
a. Land Uses: The area surrounding the project is zoned B-2M. Under current
conditions, the site has the following properties:
Impervious Area – 3.60 acres
Pervious Area – 0.84 acres
The same impervious areas will be used for the site redevelopment conditions, as the
impervious areas will be similar but slightly smaller after redevelopment, which is
conservative.
b. Changes to Existing Facilities: There are no existing storm drainage facilities on
the present site. All new facilities will be sized to accommodate stormwater for the
entire site as well as some off-site run-on areas. In general, surface flow will follow
historical patterns, draining along Aspen St. to the east, then along N. 5th Ave to the
north.
c. Changes to Floodplain: The site is not within a floodplain.
d. Proposed System Improvements: Storm drainage improvements for the site include
curb and gutter, pervious pavers, curb inlets, and a drywell underground drainage
system to collect and infiltrate stormwater from the paver base gravel areas.
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4. Drainage Criteria
a. Applicable Standards: The standards for this project shall meet those in the 2004
City of Bozeman Design Standards and Specifications which details the requirements
for various drainage facilities. The Montana Post-Construction Stormwater BMP
Design Guidance Manual was referenced for guidance on the design of pervious paver
systems.
b. Design Storm Analysis: The 10-year, 2-hour storm event was used to calculate runoff
rates and volumes for design. Conveyance for the site shall be sized to manage the full
10-year, 2-hour storm event. As there are no existing stormwater management facilities
currently serving this site and no increase in impervious area, it was determined that
stormwater infiltration rates and storage volumes would not be required to meet the
design storm.
c. Geotechnical Analysis: The geotechnical report for the site to the north at Aspen St.
and N. 5th Ave prepared by Rawhide Engineering dated October 5, 2018 was
referenced for this project. The report indicates site soils are composed of lean clay
with sand overlying gravel with sand and cobbles. The geotechnical report has been
attached to the Appendix D of this report. Additionally, the NRCS Soil Classification
report indicates that the site is composed of Hydrologic Soil Group C, and has been
attached to this report in Appendix C.
d. Hydrologic Methods:
1. Rainfall: Rainfall data for the subdivision improvements has been
taken from the 2004 City of Bozeman Design Standards and
Specifications, Figures I-2 and I-3.
2. Runoff Methods and Computer Models: The Rational Method has
been used to calculate the runoff rates and volumes as the site is
smaller than five acres. The time of concentration was calculated
using the TR-55 equations. Exhibit A in Appendix B shows these
subbasins.
e. State or Federal Regulations: No pertinent state or federal regulations apply to this
site.
B. PROPOSED DRAINAGE SYSTEM
1. Drainage Patterns: In general, the street has been designed to sheet flow from the crown of
Aspen St. to the parking area, which is surfaced with pervious pavers. The boulevard areas will
be paved with pervious pavers as well to collect flow from adjacent commercial areas. From
stations 0+00 to 3+28, Aspen St. has been crowned along the edge of the southern parking
areas rather than the center of the street. The surface flow from stations 3+28 to the end of
Aspen St. flows entirely north to the northern curb. Stormwater will infiltrate through the
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pervious pavers into base gravel below the pavers. Stormwater will then flow down through
the base gravel along the general Aspen St. grade to the east. Finally, stormwater is collected
at the eastern edge of the site in one of two drywells and infiltrated to the underlying gravel
layer there. The drywells will each be fitted with a 2-foot by 3-foot inlet casting to intercept
any inflow not infiltrated into the pavers. An eight-inch pipe laid flat between the two drywells
has been provided to allow flow to distribute between both drywells for optimum infiltration
rates.
Drainage patterns were analyzed in six different subbasins to determine peak flowrates
through various areas of the site. The overall area was analyzed to estimate the peak flowrate
to the drywell infiltration area and hydraulic conductivity through the paver base area.
2. Off-Site Runoff Considerations: Several off-site run-on areas totaling four acres to the south
has been considered in the analysis. This run-on enters the site from the southeastern curb
radius of Aspen St. from the N. 7th Ave run-on, or over the southern boulevard area from the
commercial properties from the south.
Additional run-on will occur from N. 5th Ave south of Aspen St., and enter the new storm
drain curb inlets directly to the drywells. If the drywells are at capacity, these inlets will
overflow out along N. 5th Ave to the north following historic runoff patterns. This run-on area
from N. 5th Ave was not considered in paver conveyance calculations since it will not flow to
any of the proposed pavers in Aspen St.
3. Proposed Drainage Improvements:
Stormwater Conveyance
The gravel base layers beneath the pavers act as conveyance for some of the site outflow. As
stormwater is collected at the pervious pavers and infiltrates down to the base storage layers,
it can also flow downhill as the street is graded towards the east. At the eastern boundary of
the site, flow from the gravel base layers is collected in two drywells. Flow into the drywells
will come from the underlying gravel base layer as well as two curb inlets on the east side of
N. 5th Ave. In events larger than the design storm, overflow will be directed from these inlets
and flow to the north along the double gutter between the east side of N. 5th Ave and the new
angled parking area, following historical drainage patterns.
Peak flow for the 10-year, 2-hour storm was calculated to be approximately 8.56 cfs for the
entire site. The conveyance facilities consist of approximately 11,825 square feet of gravel base
area under the pavers. The gravel base layer selected for this design is 18 inches thick with
approximately 40 percent porosity. The minimum base depth to provide volume per equation
4.5-1 of the Montana Post-Construction Stormwater BMP Design Guidance Manual is about
17 inches. The design base section provided meets this recommendation, and does not include
the leveling layer immediately below the pavers.
Gutter flow spread for the peak flow rate was analyzed assuming full flow in one gutter due
to the cross slope of the street. To meet the City of Bozeman maximum spread width of 9.5’,
it was calculated that most of the peak flowrate could be carried in the gutter while the
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remaining flowrate of 0.44 cfs would be carried through the paver base gravels. Given a
minimum base gravel cross section of 18 inches by ten feet wide, the average flow velocity
through the gravels at this flowrate was calculated to be 0.02 ft/s. The available flow velocity
through gravels is expected to be greater than 0.02 ft/s. Therefore, it was determined that the
selected paver depth is adequate to meet the City of Bozeman design guidelines. This base
section depth was also selected to match the street section depth, which ensures a similar level
of strength between both the pavers and the asphalt areas, as well as improving
constructability. If flows exceed the calculations provided, the curb and gutter will continue
to direct flow to the drywells or offsite while maintaining access through Aspen St.
Paver conveyance areas are hydraulically connected to the drywells by connecting the paver
base gravels to the drywell gravels. The paver base gravels across N. 5th Ave will be sloped at
the bottom to direct lower flows to the drywells. The profile drawings included with this report
show this slope in detail.
Stormwater Infiltration Facilities
As mentioned previously, stormwater detention and infiltration facilities were not required to
be designed to the design storm standard. Site constraints restricted design, such as the small
area of pervious pavers receiving flow from a relatively large offsite run-on area. No additional
impervious area or runoff will be created by this project. However, some storage volume and
infiltration area has been provided. Total storage volumes were calculated for this project but
ultimately not used as a basis for design. The total storage volume is the 10,573 cubic feet of
runoff minus the infiltrated amount of 3,120 cubic feet for the duration of the 10-year 2-hour
storm, equal to about 7,450 cubic feet. Void spaces in the paver base gravels were calculated
to be 7,095 cubic feet, but due to site slopes along Aspen St. this full volume will not act as
stormwater storage. A storage volume of 1,100 cubic feet has been provided in the drywells
and drywell gravels. Other gravel base layers were not considered in the calculation of the
stormwater storage area.
Gravel depths in the drywell areas appear to be about 6.5 to 10 feet below ground surface,
according to geotechnical investigations in the surrounding area. The drywell will be extended
below this depth. The geotechnical report indicates infiltration rates of 1.3 in/hr in the clay
layer and 3.5 in/hr in gravels. Therefore the paver base area will provide up to 0.41 cfs of
infiltration over the total area while the drywells will provide 0.02 cfs. Again due to site slopes,
infiltration rates are expected to be reduced along Aspen St. The full volume of the design
storm is expected to drain well within the maximum 48 hours recommended by the Montana
Post-Construction Stormwater BMP Design Guidance Manual.
4. Included Calculations: Peak flows have been included in Appendix B of this report.
C. SUMMARY
1. Relations to Off-Site Drainage Features: Runoff from the site will flow to the proposed
drywells at a rate equal to or lower than the rate for the predeveloped site condition, and either
infiltrate to the ground or continue along historic drainage patterns north along N. 5th Ave.
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2. Summary of Proposed Improvements: On-site storm drainage improvements include curb
and gutter, pervious pavers, curb inlets, and a drywell underground drainage system to collect
and infiltrate stormwater from the paver storage areas. No off-site improvements are
proposed.
3. Floodplain Impact: No floodplains will be impacted by this the proposed improvements.
4. State or Federal Regulations: No pertinent state or federal regulations apply to this site.
5. Compliance with Regulations and Standards: The storm improvements for the site have
been designed per the 2004 City of Bozeman Design Standards and Specifications, with the
exceptions noted previously.
References
City of Bozeman, City Engineering Division, 2004. Stormwater Management Manual, Bozeman,
Montana.
HDR and Montana Department of Environmental Quality, 2017. Montana Post-Construction
Stormwater BMP Design Guidance Manual. Retrieved from:
https://www.bozeman.net/home/showdocument?id=5325
Montana Department of Environmental Quality, 2017. Montana Standards for Subdivision Storm
Water Drainage, Circular DEQ-8, Montana.
Natural Resources Conservation Service, 1986. Urban Hydrology for Small Watersheds, TR-55
United States Department of Agriculture.
APPENDICES
A. Floodplain Map
B. Hydrology Calculations and Exhibits
Post-Development Drainage Basins (Exhibit A)
Post-Development Runoff Rates and Volumes (includes Post-Development Time of
Concentration Calculations)
Volume and Conveyance Calculations
Profile Drawings
C. NRCS Soils Information
D. Original Geotechnical Report
APPENDIX A: FLOODPLAIN MAP BOZEMAN URBAN RENEWAL DISTRICT: ASPEN STREET
18098.06
USGS The National Map: Orthoimagery. Data refreshed April, 2019.
National Flood Hazard Layer FIRMette
0 500 1,000 1,500 2,000250Feet
Ü111°3'0.60"W 45°41'27.71"N 111°2'23.15"W 45°41'2.57"N
SEE FIS REPORT FOR DETAILED LEGEND AND INDEX MAP FOR FIRM PANEL LAYOUT
SPECIAL FLOODHAZARD AREAS
Without Base Flood Elevation (BFE)Zone A, V, A99With BFE or Depth Zone AE, AO, AH, VE, AR
Regulatory Floodway
0.2% Annual Chance Flood Hazard, Areasof 1% annual chance flood with averagedepth less than one foot or with drainageareas of less than one square mile Zone X
Future Conditions 1% AnnualChance Flood Hazard Zone XArea with Reduced Flood Risk due toLevee. See Notes.Zone XArea with Flood Risk due to LeveeZone D
NO SCREEN Area of Minimal Flood Hazard Zone X
Area of Undetermined Flood Hazard Zone D
Channel, Culvert, or Storm SewerLevee, Dike, or Floodwall
Cross Sections with 1% Annual Chance17.5 Water Surface ElevationCoastal Transect
Coastal Transect BaselineProfile BaselineHydrographic Feature
Base Flood Elevation Line (BFE)
Effective LOMRs
Limit of StudyJurisdiction Boundary
Digital Data Available
No Digital Data Available
Unmapped
This map complies with FEMA's standards for the use of digital flood maps if it is not void as described below. The basemap shown complies with FEMA's basemap accuracy standards
The flood hazard information is derived directly from theauthoritative NFHL web services provided by FEMA. This mapwas exported on 1/6/2020 at 2:23:54 PM and does notreflect changes or amendments subsequent to this date andtime. The NFHL and effective information may change orbecome superseded by new data over time.
This map image is void if the one or more of the following mapelements do not appear: basemap imagery, flood zone labels,legend, scale bar, map creation date, community identifiers,FIRM panel number, and FIRM effective date. Map images forunmapped and unmodernized areas cannot be used forregulatory purposes.
Legend
OTHER AREAS OFFLOOD HAZARD
OTHER AREAS
GENERALSTRUCTURES
OTHERFEATURES
MAP PANELS
8
1:6,000
B 20.2
The pin displayed on the map is an approximate point selected by the user and does not represent an authoritative property location.
APPENDIX B: HYDROLOGY CALCULATIONS AND EXHIBITS BOZEMAN URBAN RENEWAL DISTRICT: ASPEN STREET
18098.06
1.15 ac.2.22 ac.0.62 ac.
0.05 ac.
0.31 ac.
0.08 ac.
Project: Aspen Street
Project #: 18098.06
Date: 1/6/2020
Design Storm Frequency =10 years
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)
19478 0.45 0.9 1 0.90 0.90 0.4024
174122 4.00 0.8 1 0.80 0.80 3.1978
193600 4.4444 3.6003
SCjAj
SAj
Where Cj is the adjusted runoff coefficient for surface type j Cwd x Cf x SAj =3.60
and Aj is the area of surface type j
Flow Type Slope Length (ft)
Roughness
Coefficent
Hydraulic
Radius (ft)Velocity (ft/s)Time
(min)
Sheet 0.030 ft/ft 60 0.013 N/A N/A 0.95
Channel 0.013 ft/ft 710 0.013 0.1 2.82 4.20
Sheet 0.020 ft/ft 30 0.013 N/A N/A 1.29
Gutter Flow 0.024 ft/ft 498 0.013 0.1 3.83 2.17
Total Travel Time = 8.6 minutes
Rainfall Rainfall Peak Flow
Duration, t Intensity, i
= Cwd x SAj x i
(min) (in/hr)(ft3/s)
1 9.16 32.98
5 3.22 11.59
10 2.05 7.38
15 1.58 5.67
20 1.31 4.71
25 1.13 4.07
30 1.00 3.62
35 0.91 3.27
40 0.83 3.00
45 0.77 2.78
50 0.72 2.59
55 0.68 2.44
60 0.64 2.30
75 0.55 1.99
90 0.49 1.77
105 0.44 1.60
120 0.41 1.47
150 0.35 1.27
180 0.31 1.13
360 0.20 0.72
720 0.13 0.46
1440 0.08 0.29
10,572.52 ft3 8.56 (ft3/s)
Streets
RATIONAL METHOD FOR RUNOFF CALCULATIONS
Overall Watershed
Surface Type
Commercial Downtown
Totals
Weighted Runoff Coefficient, Cwd == 0.8101 0.81
Runoff Volume Discharge Volume Site Detention
= Cwd x SAj x i x t = d x t = Runoff Volume - Discharge Volume
Cwd x Cf =
(ft3) (ft
3) (ft
3)
1979.09 0.00 1979.09
3476.20 0.00 3476.20
4430.63 0.00 4430.63
5106.19 0.00 5106.19
5647.10 0.00 5647.10
6105.82 0.00 6105.82
6508.15 0.00 6508.15
6868.93 0.00 6868.93
7197.57 0.00 7197.57
7500.49 0.00 7500.49
7782.24 0.00 7782.24
8046.22 0.00 8046.22
8295.03 0.00 8295.03
8968.85 0.00 8968.85
9559.83 0.00 9559.83
10089.77 0.00 10089.77
10572.52 0.00 10572.52
11431.34 0.00 11431.34
12184.58 0.00 12184.58
25228.53 0.00 25228.53
15529.98 0.00 15529.98
19793.91 0.00 19793.91
Project: Aspen Street
Project #: 18098.06
Date: 1/6/2020
Design Storm Frequency =10 years
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)
50145.5 1.15 0.8 1 0.80 0.80 0.9209
50145.5 1.1512 0.9209
SCjAj
SAj
Where Cj is the adjusted runoff coefficient for surface type j Cwd x Cf x SAj =0.92
and Aj is the area of surface type j
Flow Type Slope Length (ft)
Roughness
Coefficent
Hydraulic
Radius (ft)Velocity (ft/s)Time
(min)
Sheet 0.03 ft/ft 60 0.013 N/A N/A 1.44
Channel 0.013 ft/ft 710 0.013 0.1 2.82 4.20
Total Travel Time = 5.6 minutes
Rainfall Rainfall Peak Flow
Duration, t Intensity, i
= Cwd x SAj x i
(min) (in/hr)(ft3/s)
1 9.16 8.44
5 3.22 2.96
10 2.05 1.89
15 1.58 1.45
20 1.31 1.20
25 1.13 1.04
30 1.00 0.92
35 0.91 0.84
40 0.83 0.77
45 0.77 0.71
50 0.72 0.66
55 0.68 0.62
60 0.64 0.59
75 0.55 0.51
90 0.49 0.45
105 0.44 0.41
120 0.41 0.38
150 0.35 0.32
180 0.31 0.29
360 0.20 0.18
720 0.13 0.12
1440 0.08 0.07
2,704.44 ft3 2.83 (ft3/s)
5063.26 0.00 5063.26
6453.43 0.00 6453.43
3116.80 0.00 3116.80
3972.55 0.00 3972.55
2704.44 0.00 2704.44
2924.12 0.00 2924.12
2445.39 0.00 2445.39
2580.95 0.00 2580.95
2121.86 0.00 2121.86
2294.22 0.00 2294.22
1990.69 0.00 1990.69
2058.21 0.00 2058.21
1841.13 0.00 1841.13
1918.62 0.00 1918.62
1664.78 0.00 1664.78
1757.06 0.00 1757.06
1444.52 0.00 1444.52
1561.86 0.00 1561.86
1133.35 0.00 1133.35
1306.16 0.00 1306.16
506.25 0.00 506.25
889.21 0.00 889.21
= Cwd x SAj x i x t = d x t = Runoff Volume - Discharge Volume
(ft3) (ft
3) (ft
3)
= 0.8000 Cwd x Cf =0.80
Runoff Volume Discharge Volume Site Detention
Weighted Runoff Coefficient, Cwd =
Totals
Commercial Downtown
RATIONAL METHOD FOR RUNOFF CALCULATIONS
Watershed A
Surface Type
Project: Aspen Street
Project #: 18098.06
Date: 1/6/2020
Design Storm Frequency =10 years
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)
96909.2 2.22 0.8 1 0.80 0.80 1.7798
96909.2 2.2247 1.7798
SCjAj
SAj
Where Cj is the adjusted runoff coefficient for surface type j Cwd x Cf x SAj =1.78
and Aj is the area of surface type j
Flow Type Slope Length (ft)
Roughness
Coefficent
Hydraulic
Radius (ft)Velocity (ft/s)Time
(min)
Sheet 0.039 ft/ft 95 0.013 N/A N/A 1.76
Shallow 1.1 % 305 N/A N/A 2.13 2.39
Channel 0.028 ft/ft 85 0.013 0.1 4.13 0.34
Total Travel Time = 4.5 minutes
Rainfall Rainfall Peak Flow
Duration, t Intensity, i
= Cwd x SAj x i
(min) (in/hr)(ft3/s)
1 9.16 16.31
5 3.22 5.73
10 2.05 3.65
15 1.58 2.80
20 1.31 2.33
25 1.13 2.01
30 1.00 1.79
35 0.91 1.62
40 0.83 1.48
45 0.77 1.37
50 0.72 1.28
55 0.68 1.21
60 0.64 1.14
75 0.55 0.99
90 0.49 0.88
105 0.44 0.79
120 0.41 0.73
150 0.35 0.63
180 0.31 0.56
360 0.20 0.36
720 0.13 0.23
1440 0.08 0.14
5,226.49 ft3 7.09 (ft3/s)
12471.64 0.00 12471.64
7677.19 0.00 7677.19
9785.05 0.00 9785.05
5651.04 0.00 5651.04
6023.40 0.00 6023.40
4987.84 0.00 4987.84
5226.49 0.00 5226.49
4433.72 0.00 4433.72
4725.87 0.00 4725.87
3977.62 0.00 3977.62
4100.62 0.00 4100.62
3707.84 0.00 3707.84
3847.12 0.00 3847.12
3395.63 0.00 3395.63
3558.10 0.00 3558.10
3018.39 0.00 3018.39
3217.28 0.00 3217.28
2524.23 0.00 2524.23
2791.63 0.00 2791.63
1718.45 0.00 1718.45
2190.26 0.00 2190.26
(ft3) (ft
3) (ft
3)
978.36 0.00 978.36
0.80
Runoff Volume Discharge Volume Site Detention
= Cwd x SAj x i x t = d x t = Runoff Volume - Discharge Volume
Cwd x Cf =
Totals
Weighted Runoff Coefficient, Cwd == 0.8000
Commercial Downtown
RATIONAL METHOD FOR RUNOFF CALCULATIONS
Watershed B
Surface Type
Project: Aspen Street
Project #: 18098.06
Date: 1/6/2020
Design Storm Frequency =10 years
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)
27067.5 0.62 0.8 1 0.80 0.80 0.4971
27067.5 0.6214 0.4971
SCjAj
SAj
Where Cj is the adjusted runoff coefficient for surface type j Cwd x Cf x SAj =0.50
and Aj is the area of surface type j
Flow Type Slope Length (ft)
Roughness
Coefficent
Hydraulic
Radius (ft)Velocity (ft/s)Time
(min)
Sheet 0.032 ft/ft 80 0.02 N/A N/A 2.18
Shallow 5 % 175 N/A N/A 4.54 0.64
Channel 0.03 ft/ft 25 0.013 0.1 4.28 0.10
Total Travel Time = 2.9 minutes
Rainfall Rainfall Peak Flow
Duration, t Intensity, i
= Cwd x SAj x i
(min) (in/hr)(ft3/s)
1 9.16 4.55
5 3.22 1.60
10 2.05 1.02
15 1.58 0.78
20 1.31 0.65
25 1.13 0.56
30 1.00 0.50
35 0.91 0.45
40 0.83 0.41
45 0.77 0.38
50 0.72 0.36
55 0.68 0.34
60 0.64 0.32
75 0.55 0.28
90 0.49 0.24
105 0.44 0.22
120 0.41 0.20
150 0.35 0.18
180 0.31 0.16
360 0.20 0.10
720 0.13 0.06
1440 0.08 0.04
1,459.80 ft3 3.14 (ft3/s)
3483.43 0.00 3483.43
2144.30 0.00 2144.30
2733.04 0.00 2733.04
1578.38 0.00 1578.38
1682.38 0.00 1682.38
1393.14 0.00 1393.14
1459.80 0.00 1459.80
1238.37 0.00 1238.37
1319.97 0.00 1319.97
1110.98 0.00 1110.98
1145.34 0.00 1145.34
1035.63 0.00 1035.63
1074.53 0.00 1074.53
948.43 0.00 948.43
993.80 0.00 993.80
843.06 0.00 843.06
898.61 0.00 898.61
705.04 0.00 705.04
779.72 0.00 779.72
479.98 0.00 479.98
611.76 0.00 611.76
(ft3) (ft
3) (ft
3)
273.26 0.00 273.26
0.80
Runoff Volume Discharge Volume Site Detention
= Cwd x SAj x i x t = d x t = Runoff Volume - Discharge Volume
Cwd x Cf =
Totals
Weighted Runoff Coefficient, Cwd == 0.8000
Commercial Downtown
RATIONAL METHOD FOR RUNOFF CALCULATIONS
Watershed C
Surface Type
Project: Aspen Street
Project #: 18098.06
Date: 1/6/2020
Design Storm Frequency =10 years
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)
2114.5 0.05 0.9 1 0.90 0.90 0.0437
2114.5 0.0485 0.0437
SCjAj
SAj
Where Cj is the adjusted runoff coefficient for surface type j Cwd x Cf x SAj =0.04
and Aj is the area of surface type j
Flow Type Slope Length (ft)
Roughness
Coefficent
Hydraulic
Radius (ft)Velocity (ft/s)Time
(min)
Sheet 0.015 ft/ft 20 0.013 N/A N/A 0.60
Channel 0.092 ft/ft 160 0.013 0.1 7.49 0.36
Total Travel Time = 1.0 minute
Rainfall Rainfall Peak Flow
Duration, t Intensity, i
= Cwd x SAj x i
(min) (in/hr)(ft3/s)
1 9.16 0.40
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 0.02
180 0.31 0.01
360 0.20 0.01
720 0.13 0.01
1440 0.08 0.00
128.29 ft3 0.40 (ft3/s)
306.14 0.00 306.14
188.45 0.00 188.45
240.19 0.00 240.19
138.72 0.00 138.72
147.86 0.00 147.86
122.44 0.00 122.44
128.29 0.00 128.29
108.83 0.00 108.83
116.01 0.00 116.01
97.64 0.00 97.64
100.66 0.00 100.66
91.02 0.00 91.02
94.43 0.00 94.43
83.35 0.00 83.35
87.34 0.00 87.34
74.09 0.00 74.09
78.97 0.00 78.97
61.96 0.00 61.96
68.53 0.00 68.53
42.18 0.00 42.18
53.76 0.00 53.76
(ft3) (ft
3) (ft
3)
24.02 0.00 24.02
0.90
Runoff Volume Discharge Volume Site Detention
= Cwd x SAj x i x t = d x t = Runoff Volume - Discharge Volume
Cwd x Cf =
Totals
Weighted Runoff Coefficient, Cwd == 0.9000
Streets
RATIONAL METHOD FOR RUNOFF CALCULATIONS
Watershed D
Surface Type
Project: Aspen Street
Project #: 18098.06
Date: 1/6/2020
Design Storm Frequency =10 years
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)
13865.5 0.32 0.9 1 0.90 0.90 0.2865
13865.5 0.3183 0.2865
SCjAj
SAj
Where Cj is the adjusted runoff coefficient for surface type j Cwd x Cf x SAj =0.29
and Aj is the area of surface type j
Flow Type Slope Length (ft)
Roughness
Coefficent
Hydraulic
Radius (ft)Velocity (ft/s)Time
(min)
Sheet 0.02 ft/ft 30 0.013 N/A N/A 1.07
Channel 0.0233 ft/ft 460 0.013 0.1 3.77 2.03
Total Travel Time = 3.1 minutes
Rainfall Rainfall Peak Flow
Duration, t Intensity, i
= Cwd x SAj x i
(min) (in/hr)(ft3/s)
1 9.16 2.62
5 3.22 0.92
10 2.05 0.59
15 1.58 0.45
20 1.31 0.37
25 1.13 0.32
30 1.00 0.29
35 0.91 0.26
40 0.83 0.24
45 0.77 0.22
50 0.72 0.21
55 0.68 0.19
60 0.64 0.18
75 0.55 0.16
90 0.49 0.14
105 0.44 0.13
120 0.41 0.12
150 0.35 0.10
180 0.31 0.09
360 0.20 0.06
720 0.13 0.04
1440 0.08 0.02
841.27 ft3 1.73 (ft3/s)
2007.46 0.00 2007.46
1235.74 0.00 1235.74
1575.02 0.00 1575.02
909.60 0.00 909.60
969.54 0.00 969.54
802.85 0.00 802.85
841.27 0.00 841.27
713.66 0.00 713.66
760.68 0.00 760.68
640.25 0.00 640.25
660.04 0.00 660.04
596.82 0.00 596.82
619.24 0.00 619.24
546.57 0.00 546.57
572.72 0.00 572.72
485.85 0.00 485.85
517.86 0.00 517.86
406.30 0.00 406.30
449.35 0.00 449.35
276.60 0.00 276.60
352.55 0.00 352.55
(ft3) (ft
3) (ft
3)
157.48 0.00 157.48
0.90
Runoff Volume Discharge Volume Site Detention
= Cwd x SAj x i x t = d x t = Runoff Volume - Discharge Volume
Cwd x Cf =
Totals
Weighted Runoff Coefficient, Cwd == 0.9000
Streets
RATIONAL METHOD FOR RUNOFF CALCULATIONS
Watershed E
Surface Type
Project: Aspen Street
Project #: 18098.06
Date: 1/6/2020
Design Storm Frequency =10 years
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)
3498 0.08 0.9 1 0.90 0.90 0.0723
3498 0.0803 0.0723
SCjAj
SAj
Where Cj is the adjusted runoff coefficient for surface type j Cwd x Cf x SAj =0.07
and Aj is the area of surface type j
Flow Type Slope Length (ft)
Roughness
Coefficent
Hydraulic
Radius (ft)Velocity (ft/s)Time
(min)
Sheet 0.015 ft/ft 12 0.013 N/A N/A 0.68
Channel 0.0329 ft/ft 261 0.013 0.1 4.48 0.97
Total Travel Time = 1.6 minutes
Rainfall Rainfall Peak Flow
Duration, t Intensity, i
= Cwd x SAj x i
(min) (in/hr)(ft3/s)
1 9.16 0.66
5 3.22 0.23
10 2.05 0.15
15 1.58 0.11
20 1.31 0.09
25 1.13 0.08
30 1.00 0.07
35 0.91 0.07
40 0.83 0.06
45 0.77 0.06
50 0.72 0.05
55 0.68 0.05
60 0.64 0.05
75 0.55 0.04
90 0.49 0.04
105 0.44 0.03
120 0.41 0.03
150 0.35 0.03
180 0.31 0.02
360 0.20 0.01
720 0.13 0.01
1440 0.08 0.01
212.24 ft3 0.59 (ft3/s)
506.44 0.00 506.44
311.75 0.00 311.75
397.35 0.00 397.35
229.48 0.00 229.48
244.60 0.00 244.60
202.54 0.00 202.54
212.24 0.00 212.24
180.04 0.00 180.04
191.91 0.00 191.91
161.52 0.00 161.52
166.52 0.00 166.52
150.57 0.00 150.57
156.22 0.00 156.22
137.89 0.00 137.89
144.49 0.00 144.49
122.57 0.00 122.57
130.65 0.00 130.65
102.50 0.00 102.50
113.36 0.00 113.36
69.78 0.00 69.78
88.94 0.00 88.94
(ft3) (ft
3) (ft
3)
39.73 0.00 39.73
0.90
Runoff Volume Discharge Volume Site Detention
= Cwd x SAj x i x t = d x t = Runoff Volume - Discharge Volume
Cwd x Cf =
Totals
Weighted Runoff Coefficient, Cwd == 0.9000
Streets
RATIONAL METHOD FOR RUNOFF CALCULATIONS
Watershed F
Surface Type
Basin
Paver Area
(ft2)
Base Area
(ft2)
Base Volume
(ft3)
Runoff Volume
(ft3)
Infiltration
(ft3/s)Gutter Depth and Spread
A 131.0 239.0 143.4 2,704.4 0.0 Ku 0.56
B 2,233.6 2,645.0 1,587.0 5,226.5 0.1 n 0.016
C 2,185.4 2,627.5 1,576.5 1,459.8 0.1 Q 8.56 cfs
D 652.0 652.0 391.2 128.3 0.0 Sx (Cross Slope)3.0%
E 3,500.6 4,453.0 2,671.8 841.3 0.2 SL (Gutter Slope)3.5%
F 1,127.8 1,208.5 725.1 212.2 0.0 Width of Flow (Spread) (ft) 9.9 ft
Total 9,830 11,825 7,095 10,573 0.4 Max. Allowed Flow Spread (ft) 9.5 ft
Flow Depth (in) 3.6 in
Storage Layer Depth 1.5 ft Max. Allowed Flow Depth (in) 5.85 in
Storage Layer Porosity 40%Street Width 36 ft
Clay Infiltration Rate 1.5 in/hr Street Width Remaining 26.1 ft
Gravel Infiltration Rate 3.5 in/hr
Gravel Base Volume 7,095 ft3
Drywell Volume 144.9 ft3
Drywell Gravel Volume 955.0 ft3
Infiltrated Volume 3,121 ft3 *during 2-hour storm
Runoff Volume 10,573 ft3 *during 2-hour storm
Required Volume 7,452 ft3
Provided Volume 8,195 ft3
Conveyance Flow Calculations
Average flow velocity 0.02 ft/s
P 0.5 in Total flow 0.44 cfs
Ai 4.44 ac Min. flow width 10 ft
Rvi 0.78 Area provided 15.00 ft2
I 0.81
Ap 0.23 ac*
n 40%Gravel Infiltration 0.02 cfs
DAL 17.0 in
Recommended Minimum Aggregate Reservoir Depth
*Note that the paver surface area was used for the numerator Ap while the paver base gravel
area was used for the denominator Ap.
Volume and Conveyance Calculations
NORTH VERT. : 1" = 5'
HORIZ. : 1" = 30'
PROFILE
PLAN : 1" = 30'
SCALE
30 15 0
SCALE:1" = 30'
30 60 PRELIMINARY - FOR REVIEWFILE:PROJECT NO:CAD:QUALITY ASSURANCE:DRAWING HISTORYDATE DESCRIPTIONTASK ORDER #MID20-001ASPEN STREET - STREET & STORM DRAIN PLAN AND PROFILEASPEN ST & 5TH AVE IMPROVEMENTSBOZEMAN URBAN RENEWAL DISTRICTBOZEMAN, MONTANAC5.1 -18098_06_PNP_PROD.DWGCMK----------------18098.06
NORTH VERT. : 1" = 5'
HORIZ. : 1" = 30'
PROFILE
PLAN : 1" = 30'
SCALE
30 15 0
SCALE:1" = 30'
30 60 PRELIMINARY - FOR REVIEWFILE:PROJECT NO:CAD:QUALITY ASSURANCE:DRAWING HISTORYDATE DESCRIPTIONTASK ORDER #MID20-0015TH AVENUE - STREET & STORM DRAIN PLAN AND PROFILEASPEN ST & 5TH AVE IMPROVEMENTSBOZEMAN URBAN RENEWAL DISTRICTBOZEMAN, MONTANAC5.2 -18098_06_PNP_PROD.DWGCMK----------------18098.06
APPENDIX C: NRCS SOILS INFORMATION BOZEMAN URBAN RENEWAL DISTRICT: ASPEN STREET
18098.06
United States
Department of
Agriculture
A product of the National
Cooperative Soil Survey,
a joint effort of the United
States Department of
Agriculture and other
Federal agencies, State
agencies including the
Agricultural Experiment
Stations, and local
participants
Custom Soil Resource
Report for
Gallatin County
Area, MontanaNatural
Resources
Conservation
Service
November 21, 2019
Preface
Soil surveys contain information that affects land use planning in survey areas.
They highlight soil limitations that affect various land uses and provide information
about the properties of the soils in the survey areas. Soil surveys are designed for
many different users, including farmers, ranchers, foresters, agronomists, urban
planners, community officials, engineers, developers, builders, and home buyers.
Also, conservationists, teachers, students, and specialists in recreation, waste
disposal, and pollution control can use the surveys to help them understand,
protect, or enhance the environment.
Various land use regulations of Federal, State, and local governments may impose
special restrictions on land use or land treatment. Soil surveys identify soil
properties that are used in making various land use or land treatment decisions.
The information is intended to help the land users identify and reduce the effects of
soil limitations on various land uses. The landowner or user is responsible for
identifying and complying with existing laws and regulations.
Although soil survey information can be used for general farm, local, and wider area
planning, onsite investigation is needed to supplement this information in some
cases. Examples include soil quality assessments (http://www.nrcs.usda.gov/wps/
portal/nrcs/main/soils/health/) and certain conservation and engineering
applications. For more detailed information, contact your local USDA Service Center
(https://offices.sc.egov.usda.gov/locator/app?agency=nrcs) or your NRCS State Soil
Scientist (http://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/contactus/?
cid=nrcs142p2_053951).
Great differences in soil properties can occur within short distances. Some soils are
seasonally wet or subject to flooding. Some are too unstable to be used as a
foundation for buildings or roads. Clayey or wet soils are poorly suited to use as
septic tank absorption fields. A high water table makes a soil poorly suited to
basements or underground installations.
The National Cooperative Soil Survey is a joint effort of the United States
Department of Agriculture and other Federal agencies, State agencies including the
Agricultural Experiment Stations, and local agencies. The Natural Resources
Conservation Service (NRCS) has leadership for the Federal part of the National
Cooperative Soil Survey.
Information about soils is updated periodically. Updated information is available
through the NRCS Web Soil Survey, the site for official soil survey information.
The U.S. Department of Agriculture (USDA) prohibits discrimination in all its
programs and activities on the basis of race, color, national origin, age, disability,
and where applicable, sex, marital status, familial status, parental status, religion,
sexual orientation, genetic information, political beliefs, reprisal, or because all or a
part of an individual's income is derived from any public assistance program. (Not
all prohibited bases apply to all programs.) Persons with disabilities who require
2
alternative means for communication of program information (Braille, large print,
audiotape, etc.) should contact USDA's TARGET Center at (202) 720-2600 (voice
and TDD). To file a complaint of discrimination, write to USDA, Director, Office of
Civil Rights, 1400 Independence Avenue, S.W., Washington, D.C. 20250-9410 or
call (800) 795-3272 (voice) or (202) 720-6382 (TDD). USDA is an equal opportunity
provider and employer.
3
Contents
Preface....................................................................................................................2
How Soil Surveys Are Made..................................................................................5
Soil Map..................................................................................................................8
Soil Map................................................................................................................9
Legend................................................................................................................10
Map Unit Legend................................................................................................11
Map Unit Descriptions.........................................................................................11
Gallatin County Area, Montana.......................................................................13
50B—Blackdog silt loam, 0 to 4 percent slopes..........................................13
450C—Blackdog-Quagle silt loams, 4 to 8 percent slopes.........................14
457A—Turner loam, moderately wet, 0 to 2 percent slopes.......................16
UL—Urban land...........................................................................................18
References............................................................................................................19
4
How Soil Surveys Are Made
Soil surveys are made to provide information about the soils and miscellaneous
areas in a specific area. They include a description of the soils and miscellaneous
areas and their location on the landscape and tables that show soil properties and
limitations affecting various uses. Soil scientists observed the steepness, length,
and shape of the slopes; the general pattern of drainage; the kinds of crops and
native plants; and the kinds of bedrock. They observed and described many soil
profiles. A soil profile is the sequence of natural layers, or horizons, in a soil. The
profile extends from the surface down into the unconsolidated material in which the
soil formed or from the surface down to bedrock. The unconsolidated material is
devoid of roots and other living organisms and has not been changed by other
biological activity.
Currently, soils are mapped according to the boundaries of major land resource
areas (MLRAs). MLRAs are geographically associated land resource units that
share common characteristics related to physiography, geology, climate, water
resources, soils, biological resources, and land uses (USDA, 2006). Soil survey
areas typically consist of parts of one or more MLRA.
The soils and miscellaneous areas in a survey area occur in an orderly pattern that
is related to the geology, landforms, relief, climate, and natural vegetation of the
area. Each kind of soil and miscellaneous area is associated with a particular kind
of landform or with a segment of the landform. By observing the soils and
miscellaneous areas in the survey area and relating their position to specific
segments of the landform, a soil scientist develops a concept, or model, of how they
were formed. Thus, during mapping, this model enables the soil scientist to predict
with a considerable degree of accuracy the kind of soil or miscellaneous area at a
specific location on the landscape.
Commonly, individual soils on the landscape merge into one another as their
characteristics gradually change. To construct an accurate soil map, however, soil
scientists must determine the boundaries between the soils. They can observe only
a limited number of soil profiles. Nevertheless, these observations, supplemented
by an understanding of the soil-vegetation-landscape relationship, are sufficient to
verify predictions of the kinds of soil in an area and to determine the boundaries.
Soil scientists recorded the characteristics of the soil profiles that they studied. They
noted soil color, texture, size and shape of soil aggregates, kind and amount of rock
fragments, distribution of plant roots, reaction, and other features that enable them
to identify soils. After describing the soils in the survey area and determining their
properties, the soil scientists assigned the soils to taxonomic classes (units).
Taxonomic classes are concepts. Each taxonomic class has a set of soil
characteristics with precisely defined limits. The classes are used as a basis for
comparison to classify soils systematically. Soil taxonomy, the system of taxonomic
classification used in the United States, is based mainly on the kind and character
of soil properties and the arrangement of horizons within the profile. After the soil
5
scientists classified and named the soils in the survey area, they compared the
individual soils with similar soils in the same taxonomic class in other areas so that
they could confirm data and assemble additional data based on experience and
research.
The objective of soil mapping is not to delineate pure map unit components; the
objective is to separate the landscape into landforms or landform segments that
have similar use and management requirements. Each map unit is defined by a
unique combination of soil components and/or miscellaneous areas in predictable
proportions. Some components may be highly contrasting to the other components
of the map unit. The presence of minor components in a map unit in no way
diminishes the usefulness or accuracy of the data. The delineation of such
landforms and landform segments on the map provides sufficient information for the
development of resource plans. If intensive use of small areas is planned, onsite
investigation is needed to define and locate the soils and miscellaneous areas.
Soil scientists make many field observations in the process of producing a soil map.
The frequency of observation is dependent upon several factors, including scale of
mapping, intensity of mapping, design of map units, complexity of the landscape,
and experience of the soil scientist. Observations are made to test and refine the
soil-landscape model and predictions and to verify the classification of the soils at
specific locations. Once the soil-landscape model is refined, a significantly smaller
number of measurements of individual soil properties are made and recorded.
These measurements may include field measurements, such as those for color,
depth to bedrock, and texture, and laboratory measurements, such as those for
content of sand, silt, clay, salt, and other components. Properties of each soil
typically vary from one point to another across the landscape.
Observations for map unit components are aggregated to develop ranges of
characteristics for the components. The aggregated values are presented. Direct
measurements do not exist for every property presented for every map unit
component. Values for some properties are estimated from combinations of other
properties.
While a soil survey is in progress, samples of some of the soils in the area generally
are collected for laboratory analyses and for engineering tests. Soil scientists
interpret the data from these analyses and tests as well as the field-observed
characteristics and the soil properties to determine the expected behavior of the
soils under different uses. Interpretations for all of the soils are field tested through
observation of the soils in different uses and under different levels of management.
Some interpretations are modified to fit local conditions, and some new
interpretations are developed to meet local needs. Data are assembled from other
sources, such as research information, production records, and field experience of
specialists. For example, data on crop yields under defined levels of management
are assembled from farm records and from field or plot experiments on the same
kinds of soil.
Predictions about soil behavior are based not only on soil properties but also on
such variables as climate and biological activity. Soil conditions are predictable over
long periods of time, but they are not predictable from year to year. For example,
soil scientists can predict with a fairly high degree of accuracy that a given soil will
have a high water table within certain depths in most years, but they cannot predict
that a high water table will always be at a specific level in the soil on a specific date.
After soil scientists located and identified the significant natural bodies of soil in the
survey area, they drew the boundaries of these bodies on aerial photographs and
Custom Soil Resource Report
6
identified each as a specific map unit. Aerial photographs show trees, buildings,
fields, roads, and rivers, all of which help in locating boundaries accurately.
Custom Soil Resource Report
7
Soil Map
The soil map section includes the soil map for the defined area of interest, a list of
soil map units on the map and extent of each map unit, and cartographic symbols
displayed on the map. Also presented are various metadata about data used to
produce the map, and a description of each soil map unit.
8
9
Custom Soil Resource Report
Soil Map
50590905059150505921050592705059330505939050594505059090505915050592105059270505933050593905059450496200 496260 496320 496380 496440 496500 496560 496620 496680 496740 496800
496200 496260 496320 496380 496440 496500 496560 496620 496680 496740 496800
45° 41' 19'' N 111° 2' 55'' W45° 41' 19'' N111° 2' 27'' W45° 41' 6'' N
111° 2' 55'' W45° 41' 6'' N
111° 2' 27'' WN
Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 12N WGS84
0 100 200 400 600
Feet
0 40 80 160 240
Meters
Map Scale: 1:2,780 if printed on A landscape (11" x 8.5") sheet.
Soil Map may not be valid at this scale.
MAP LEGEND MAP INFORMATION
Area of Interest (AOI)
Area of Interest (AOI)
Soils
Soil Map Unit Polygons
Soil Map Unit Lines
Soil Map Unit Points
Special Point Features
Blowout
Borrow Pit
Clay Spot
Closed Depression
Gravel Pit
Gravelly Spot
Landfill
Lava Flow
Marsh or swamp
Mine or Quarry
Miscellaneous Water
Perennial Water
Rock Outcrop
Saline Spot
Sandy Spot
Severely Eroded Spot
Sinkhole
Slide or Slip
Sodic Spot
Spoil Area
Stony Spot
Very Stony Spot
Wet Spot
Other
Special Line Features
Water Features
Streams and Canals
Transportation
Rails
Interstate Highways
US Routes
Major Roads
Local Roads
Background
Aerial Photography
The soil surveys that comprise your AOI were mapped at
1:24,000.
Warning: Soil Map may not be valid at this scale.
Enlargement of maps beyond the scale of mapping can cause
misunderstanding of the detail of mapping and accuracy of soil
line placement. The maps do not show the small areas of
contrasting soils that could have been shown at a more detailed
scale.
Please rely on the bar scale on each map sheet for map
measurements.
Source of Map: Natural Resources Conservation Service
Web Soil Survey URL:
Coordinate System: Web Mercator (EPSG:3857)
Maps from the Web Soil Survey are based on the Web Mercator
projection, which preserves direction and shape but distorts
distance and area. A projection that preserves area, such as the
Albers equal-area conic projection, should be used if more
accurate calculations of distance or area are required.
This product is generated from the USDA-NRCS certified data as
of the version date(s) listed below.
Soil Survey Area: Gallatin County Area, Montana
Survey Area Data: Version 23, Sep 16, 2019
Soil map units are labeled (as space allows) for map scales
1:50,000 or larger.
Date(s) aerial images were photographed: Aug 3, 2009—Sep 1,
2016
The orthophoto or other base map on which the soil lines were
compiled and digitized probably differs from the background
imagery displayed on these maps. As a result, some minor
shifting of map unit boundaries may be evident.
Custom Soil Resource Report
10
Map Unit Legend
Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI
50B Blackdog silt loam, 0 to 4
percent slopes
18.2 60.1%
450C Blackdog-Quagle silt loams, 4
to 8 percent slopes
6.2 20.4%
457A Turner loam, moderately wet, 0
to 2 percent slopes
5.7 18.8%
UL Urban land 0.2 0.7%
Totals for Area of Interest 30.4 100.0%
Map Unit Descriptions
The map units delineated on the detailed soil maps in a soil survey represent the
soils or miscellaneous areas in the survey area. The map unit descriptions, along
with the maps, can be used to determine the composition and properties of a unit.
A map unit delineation on a soil map represents an area dominated by one or more
major kinds of soil or miscellaneous areas. A map unit is identified and named
according to the taxonomic classification of the dominant soils. Within a taxonomic
class there are precisely defined limits for the properties of the soils. On the
landscape, however, the soils are natural phenomena, and they have the
characteristic variability of all natural phenomena. Thus, the range of some
observed properties may extend beyond the limits defined for a taxonomic class.
Areas of soils of a single taxonomic class rarely, if ever, can be mapped without
including areas of other taxonomic classes. Consequently, every map unit is made
up of the soils or miscellaneous areas for which it is named and some minor
components that belong to taxonomic classes other than those of the major soils.
Most minor soils have properties similar to those of the dominant soil or soils in the
map unit, and thus they do not affect use and management. These are called
noncontrasting, or similar, components. They may or may not be mentioned in a
particular map unit description. Other minor components, however, have properties
and behavioral characteristics divergent enough to affect use or to require different
management. These are called contrasting, or dissimilar, components. They
generally are in small areas and could not be mapped separately because of the
scale used. Some small areas of strongly contrasting soils or miscellaneous areas
are identified by a special symbol on the maps. If included in the database for a
given area, the contrasting minor components are identified in the map unit
descriptions along with some characteristics of each. A few areas of minor
components may not have been observed, and consequently they are not
mentioned in the descriptions, especially where the pattern was so complex that it
was impractical to make enough observations to identify all the soils and
miscellaneous areas on the landscape.
The presence of minor components in a map unit in no way diminishes the
usefulness or accuracy of the data. The objective of mapping is not to delineate
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pure taxonomic classes but rather to separate the landscape into landforms or
landform segments that have similar use and management requirements. The
delineation of such segments on the map provides sufficient information for the
development of resource plans. If intensive use of small areas is planned, however,
onsite investigation is needed to define and locate the soils and miscellaneous
areas.
An identifying symbol precedes the map unit name in the map unit descriptions.
Each description includes general facts about the unit and gives important soil
properties and qualities.
Soils that have profiles that are almost alike make up a soil series. Except for
differences in texture of the surface layer, all the soils of a series have major
horizons that are similar in composition, thickness, and arrangement.
Soils of one series can differ in texture of the surface layer, slope, stoniness,
salinity, degree of erosion, and other characteristics that affect their use. On the
basis of such differences, a soil series is divided into soil phases. Most of the areas
shown on the detailed soil maps are phases of soil series. The name of a soil phase
commonly indicates a feature that affects use or management. For example, Alpha
silt loam, 0 to 2 percent slopes, is a phase of the Alpha series.
Some map units are made up of two or more major soils or miscellaneous areas.
These map units are complexes, associations, or undifferentiated groups.
A complex consists of two or more soils or miscellaneous areas in such an intricate
pattern or in such small areas that they cannot be shown separately on the maps.
The pattern and proportion of the soils or miscellaneous areas are somewhat similar
in all areas. Alpha-Beta complex, 0 to 6 percent slopes, is an example.
An association is made up of two or more geographically associated soils or
miscellaneous areas that are shown as one unit on the maps. Because of present
or anticipated uses of the map units in the survey area, it was not considered
practical or necessary to map the soils or miscellaneous areas separately. The
pattern and relative proportion of the soils or miscellaneous areas are somewhat
similar. Alpha-Beta association, 0 to 2 percent slopes, is an example.
An undifferentiated group is made up of two or more soils or miscellaneous areas
that could be mapped individually but are mapped as one unit because similar
interpretations can be made for use and management. The pattern and proportion
of the soils or miscellaneous areas in a mapped area are not uniform. An area can
be made up of only one of the major soils or miscellaneous areas, or it can be made
up of all of them. Alpha and Beta soils, 0 to 2 percent slopes, is an example.
Some surveys include miscellaneous areas. Such areas have little or no soil
material and support little or no vegetation. Rock outcrop is an example.
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Gallatin County Area, Montana
50B—Blackdog silt loam, 0 to 4 percent slopes
Map Unit Setting
National map unit symbol: 56vq
Elevation: 4,350 to 5,500 feet
Mean annual precipitation: 15 to 19 inches
Mean annual air temperature: 37 to 43 degrees F
Frost-free period: 90 to 110 days
Farmland classification: All areas are prime farmland
Map Unit Composition
Blackdog and similar soils: 90 percent
Minor components: 10 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
Description of Blackdog
Setting
Landform: Stream terraces
Down-slope shape: Linear
Across-slope shape: Linear
Parent material: Calcareous loess
Typical profile
A - 0 to 10 inches: silt loam
Bt - 10 to 19 inches: silty clay loam
Bk - 19 to 60 inches: silt loam
Properties and qualities
Slope: 0 to 4 percent
Depth to restrictive feature: More than 80 inches
Natural drainage class: Well drained
Capacity of the most limiting layer to transmit water (Ksat): Moderately high (0.20
to 0.57 in/hr)
Depth to water table: More than 80 inches
Frequency of flooding: None
Frequency of ponding: None
Calcium carbonate, maximum in profile: 30 percent
Available water storage in profile: High (about 10.9 inches)
Interpretive groups
Land capability classification (irrigated): 3e
Land capability classification (nonirrigated): 3e
Hydrologic Soil Group: C
Ecological site: Silty (Si) 15-19" p.z. (R044XS355MT), Upland Grassland
(R044BP818MT)
Hydric soil rating: No
Minor Components
Meagher
Percent of map unit: 4 percent
Landform: Alluvial fans, stream terraces
Down-slope shape: Linear
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Across-slope shape: Linear
Ecological site: Silty (Si) 15-19" p.z. (R044XS355MT)
Hydric soil rating: No
Bowery
Percent of map unit: 3 percent
Landform: Stream terraces, alluvial fans
Down-slope shape: Linear
Across-slope shape: Linear
Ecological site: Silty (Si) 15-19" p.z. (R044XS355MT)
Hydric soil rating: No
Quagle
Percent of map unit: 3 percent
Landform: Stream terraces
Down-slope shape: Linear
Across-slope shape: Linear
Ecological site: Limy (Ly) 15-19" p.z. (R044XS357MT)
Hydric soil rating: No
450C—Blackdog-Quagle silt loams, 4 to 8 percent slopes
Map Unit Setting
National map unit symbol: 56sw
Elevation: 4,400 to 5,500 feet
Mean annual precipitation: 15 to 19 inches
Mean annual air temperature: 39 to 45 degrees F
Frost-free period: 90 to 110 days
Farmland classification: Farmland of statewide importance
Map Unit Composition
Blackdog and similar soils: 60 percent
Quagle and similar soils: 30 percent
Minor components: 10 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
Description of Blackdog
Setting
Landform: Stream terraces
Down-slope shape: Linear
Across-slope shape: Linear
Parent material: Calcareous loess
Typical profile
A - 0 to 10 inches: silt loam
Bt - 10 to 19 inches: silty clay loam
Bk - 19 to 60 inches: silt loam
Properties and qualities
Slope: 4 to 8 percent
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Depth to restrictive feature: More than 80 inches
Natural drainage class: Well drained
Capacity of the most limiting layer to transmit water (Ksat): Moderately high (0.20
to 0.57 in/hr)
Depth to water table: More than 80 inches
Frequency of flooding: None
Frequency of ponding: None
Calcium carbonate, maximum in profile: 30 percent
Available water storage in profile: High (about 10.9 inches)
Interpretive groups
Land capability classification (irrigated): 3e
Land capability classification (nonirrigated): 3e
Hydrologic Soil Group: C
Ecological site: Silty (Si) 15-19" p.z. (R044XS355MT), Upland Grassland
(R044BP818MT)
Hydric soil rating: No
Description of Quagle
Setting
Landform: Stream terraces
Down-slope shape: Linear
Across-slope shape: Linear
Parent material: Silty calcareous loess
Typical profile
A - 0 to 6 inches: silt loam
Bw - 6 to 9 inches: silt loam
Bk - 9 to 60 inches: silt loam
Properties and qualities
Slope: 4 to 8 percent
Depth to restrictive feature: More than 80 inches
Natural drainage class: Well drained
Capacity of the most limiting layer to transmit water (Ksat): Moderately high to
high (0.57 to 1.98 in/hr)
Depth to water table: More than 80 inches
Frequency of flooding: None
Frequency of ponding: None
Calcium carbonate, maximum in profile: 35 percent
Salinity, maximum in profile: Nonsaline to very slightly saline (0.0 to 2.0
mmhos/cm)
Available water storage in profile: High (about 10.8 inches)
Interpretive groups
Land capability classification (irrigated): 4e
Land capability classification (nonirrigated): 4e
Hydrologic Soil Group: B
Ecological site: Limy (Ly) 15-19" p.z. (R044XS357MT), Upland Grassland
(R044BP818MT)
Hydric soil rating: No
Minor Components
Beanlake
Percent of map unit: 5 percent
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Landform: Alluvial fans, stream terraces
Down-slope shape: Linear
Across-slope shape: Linear
Ecological site: Limy (Ly) 15-19" p.z. (R044XS357MT)
Hydric soil rating: No
Bowery
Percent of map unit: 3 percent
Landform: Alluvial fans, stream terraces
Down-slope shape: Linear
Across-slope shape: Linear
Ecological site: Silty (Si) 15-19" p.z. (R044XS355MT)
Hydric soil rating: No
Anceney
Percent of map unit: 2 percent
Landform: Stream terraces
Down-slope shape: Linear
Across-slope shape: Linear
Ecological site: Silty-Droughty (SiDr) 15-19" p.z. (R044XS690MT)
Hydric soil rating: No
457A—Turner loam, moderately wet, 0 to 2 percent slopes
Map Unit Setting
National map unit symbol: 56tb
Elevation: 4,300 to 5,200 feet
Mean annual precipitation: 15 to 19 inches
Mean annual air temperature: 39 to 45 degrees F
Frost-free period: 90 to 110 days
Farmland classification: Prime farmland if irrigated
Map Unit Composition
Turner and similar soils: 85 percent
Minor components: 15 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
Description of Turner
Setting
Landform: Stream terraces
Down-slope shape: Linear
Across-slope shape: Linear
Parent material: Alluvium
Typical profile
A - 0 to 6 inches: loam
Bt - 6 to 12 inches: clay loam
Bk - 12 to 26 inches: clay loam
2C - 26 to 60 inches: very gravelly loamy sand
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Properties and qualities
Slope: 0 to 2 percent
Depth to restrictive feature: More than 80 inches
Natural drainage class: Well drained
Capacity of the most limiting layer to transmit water (Ksat): Moderately high to
high (0.57 to 1.98 in/hr)
Depth to water table: About 48 to 96 inches
Frequency of flooding: None
Frequency of ponding: None
Calcium carbonate, maximum in profile: 15 percent
Salinity, maximum in profile: Nonsaline to very slightly saline (0.0 to 2.0
mmhos/cm)
Available water storage in profile: Low (about 5.4 inches)
Interpretive groups
Land capability classification (irrigated): 3e
Land capability classification (nonirrigated): 3e
Hydrologic Soil Group: B
Ecological site: Silty (Si) 15-19" p.z. (R044XS355MT), Upland Grassland
(R044BP818MT)
Hydric soil rating: No
Minor Components
Turner
Percent of map unit: 5 percent
Landform: Stream terraces
Down-slope shape: Linear
Across-slope shape: Linear
Ecological site: Silty (Si) 15-19" p.z. (R044XS355MT)
Hydric soil rating: No
Beaverton
Percent of map unit: 5 percent
Landform: Stream terraces, alluvial fans
Down-slope shape: Linear
Across-slope shape: Linear
Ecological site: Shallow to Gravel (SwGr) 15-19" p.z. (R044XS354MT)
Hydric soil rating: No
Meadowcreek
Percent of map unit: 5 percent
Landform: Stream terraces
Down-slope shape: Linear
Across-slope shape: Linear
Ecological site: Subirrigated (Sb) 15-19" p.z. (R044XS359MT)
Hydric soil rating: No
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UL—Urban land
Map Unit Composition
Urban land: 100 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
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References
American Association of State Highway and Transportation Officials (AASHTO).
2004. Standard specifications for transportation materials and methods of sampling
and testing. 24th edition.
American Society for Testing and Materials (ASTM). 2005. Standard classification of
soils for engineering purposes. ASTM Standard D2487-00.
Cowardin, L.M., V. Carter, F.C. Golet, and E.T. LaRoe. 1979. Classification of
wetlands and deep-water habitats of the United States. U.S. Fish and Wildlife
Service FWS/OBS-79/31.
Federal Register. July 13, 1994. Changes in hydric soils of the United States.
Federal Register. September 18, 2002. Hydric soils of the United States.
Hurt, G.W., and L.M. Vasilas, editors. Version 6.0, 2006. Field indicators of hydric
soils in the United States.
National Research Council. 1995. Wetlands: Characteristics and boundaries.
Soil Survey Division Staff. 1993. Soil survey manual. Soil Conservation Service.
U.S. Department of Agriculture Handbook 18. http://www.nrcs.usda.gov/wps/portal/
nrcs/detail/national/soils/?cid=nrcs142p2_054262
Soil Survey Staff. 1999. Soil taxonomy: A basic system of soil classification for
making and interpreting soil surveys. 2nd edition. Natural Resources Conservation
Service, U.S. Department of Agriculture Handbook 436. http://
www.nrcs.usda.gov/wps/portal/nrcs/detail/national/soils/?cid=nrcs142p2_053577
Soil Survey Staff. 2010. Keys to soil taxonomy. 11th edition. U.S. Department of
Agriculture, Natural Resources Conservation Service. http://
www.nrcs.usda.gov/wps/portal/nrcs/detail/national/soils/?cid=nrcs142p2_053580
Tiner, R.W., Jr. 1985. Wetlands of Delaware. U.S. Fish and Wildlife Service and
Delaware Department of Natural Resources and Environmental Control, Wetlands
Section.
United States Army Corps of Engineers, Environmental Laboratory. 1987. Corps of
Engineers wetlands delineation manual. Waterways Experiment Station Technical
Report Y-87-1.
United States Department of Agriculture, Natural Resources Conservation Service.
National forestry manual. http://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/
home/?cid=nrcs142p2_053374
United States Department of Agriculture, Natural Resources Conservation Service.
National range and pasture handbook. http://www.nrcs.usda.gov/wps/portal/nrcs/
detail/national/landuse/rangepasture/?cid=stelprdb1043084
19
United States Department of Agriculture, Natural Resources Conservation Service.
National soil survey handbook, title 430-VI. http://www.nrcs.usda.gov/wps/portal/
nrcs/detail/soils/scientists/?cid=nrcs142p2_054242
United States Department of Agriculture, Natural Resources Conservation Service.
2006. Land resource regions and major land resource areas of the United States,
the Caribbean, and the Pacific Basin. U.S. Department of Agriculture Handbook
296. http://www.nrcs.usda.gov/wps/portal/nrcs/detail/national/soils/?
cid=nrcs142p2_053624
United States Department of Agriculture, Soil Conservation Service. 1961. Land
capability classification. U.S. Department of Agriculture Handbook 210. http://
www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/nrcs142p2_052290.pdf
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APPENDIX D: ORIGINAL GEOTECHNICAL REPORT BOZEMAN URBAN RENEWAL DISTRICT: ASPEN STREET
18098.06