HomeMy WebLinkAbout001 Drainage Report
DRAINAGE REPORT
FOR
Intermountain Infrastructure Group, LLC
Bozeman, Montana
TD&H Engineering Project Number: S23-021-07
Prepared: December 17, 2024
TD&H ENGINEERING, INC.
303 East Second Avenue
Spokane, WA 99202
p.(509) 622-2888
f.(509) 622-2889
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The following report summary and calculations have been prepared for Intermountain
Infrastructure Group, LLC located at Red Wing Drive and is intended to provide analysis
consistent with the City of Bozeman Standards for Design and Construction.
STORM DRAIN SYSTEM
Project Description
The Intermountain Infrastructure Group proposed project is located within the SE 1/4
Section 36, Township 1 South, Range 5 East of the P.M.M., county of Gallatin in Bozeman,
Montana. The subject property parcel of land contains 9,168 square feet, 0.21 acres.
Proposed site improvements include gravel access driveway and fenced compound,
concrete generator pad, fiber hub equipment shelter, and drainage facilities.
The existing site currently consists of mostly undeveloped land with pasture/grassland
with a gravel access road along the west property line. In general, the site tends to slope
from the southwest property line to the northeast property line and has grades between
1% and 5%. Refer to the attachments for an existing site and drainage map.
Geotechnical Information
The on-site soils are assumed to be Blackdog-Quagle silt loams, 4 to 8 percent slopes
based on a soil map from the National Cooperative Soil Survey prepared by the
Natural Resources Conservation Service and obtained through the Web Soil Survey
(see attachment). The design proposes to use a soils infiltration rate of 1.0 in per
hour.
Groundwater monitoring has been initially estimated as more than 80 inches from the
proposed improvements elevation. The project will follow the industry guidance’s
three-foot minimum separation between bottom of proposed facility and the underlying
groundwater table.
No soils investigation has been conducted on site. Approximately 0.87 miles to the
northwest of the site, the Montana Department of Transportation Visitor Center has a
groundwater monitoring well. All data collected is entered into the Montana Bureau of
Mines and Geology (MBMG). Using this data, the recent measurement taken
9/10/2024 showed 6.55 feet of separation between ground and water level. Refer to
attachment for the Montana Bureau of Mines and Geology Ground Water Information
Center Hydrograph and Precipitation Graphs.
Methodology
The Rational Method was used to estimate the storm water runoff rate for both the
pre- and post-developed drainage basins. This method is an appropriate alternative
to the SCS method since the calculation P-2S is less than zero with the weighted
curve number. Refer to Appendix C for the storm water calculations. To calculate time
of concentration, the TR-55 method was used.
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Pre-Developed Conditions
The existing site has been delineated into a single drainage basin due to the site
topography, property boundary locations, and the runoff discharge location. For the
pre-development calculations, this basin was used to determine the existing runoff
volumes from the site. In general, approximately all the stormwater runoff will flow
towards the northeast. Refer to the attachments for a detailed basin map depicting
the basin delineation and the pre-development calculations.
Table 1: Pre-Development Basin Information
Pervious Conditions
Soil Type SF Acre Runoff Coefficient
Brush 26,232 0.60 0.25
Total Area 26,232 0.60 0.25
Post-Developed Conditions
The developed site includes two drainage basins as shown on the Post-Developed
Basin Map included in the attachments. One drainage basin (Basin A) contains all the
proposed site improvements to calculate the runoff volumes and flow rates that would
be stored and then discharged via the proposed bioretention basin. The other basin
will remain relatively untouched and will keep the natural drainage way. Table 2
summarizes the entire project site.
Table 2: Post-Developed Basin Information
Basin A
Soil Type SF Acre Runoff Coefficient
Roofs 432 0.01 0.90
Asphalt / Concrete 256 0.006 0.90
Gravel 2,640 0.06 0.50
Swale / Ditch 447 0.009 0.10
Total Area 3,775 0.09 0.53
Basin B
Soil Type SF Acre Runoff Coefficient
Open Space,
Undeveloped
22,483 0.52 0.25
Total Area 22,483 0.52 0.25
Basin A includes all the proposed site improvements consisting of the gravel access
driveway and fenced compound, concrete generator pad, fiber hub equipment shelter,
bioretention basin and the landscaped ditch. Runoff from the basin flows off the gravel
compound into the ditch which will flow toward the bioretention pond.
The bioretention basin has a pond bottom surface area of 140 square feet (SF) and a
1-foot treatment depth. The bioretention basin has an additional 6-inch freeboard with
a 6-inch overflow spillway located on the east side.
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Analysis Summary
Overall, the proposed development and stormwater facilities will capture, store, and
treat all new development run-off generated. The amount of run-off generated and
departing the site will be less than the current conditions and is in areas that are left
undeveloped. A comparison of the Pre-Development to Post-Developed Runoff rates
for the entire site is shown in Table 3. Refer to the attachments for the storm water
calculations.
Table 3: Pre-Development vs. Post-Developed Runoff Flow Rates
Storm Event Pre-Development Post-Developed Net Difference
2-Year Peak Flow 0.04 0.04 0
10-Year Peak Flow 0.06 0.07 0.01
25-Year Peak Flow 0.07 0.08 0.01
100-Year Peak Flow 0.09 0.11 0.02
Water Quality Treatment BMPs
Water quality treatment for the project will be achieved through the bioretention basin.
Required runoff treatment volumes and flowrates for the project were determined
using the Montana Post-Construction Storm Water BMP Design Manual and are
included in the attachments. The bioretention basin is a full infiltration system and
designed to store 100% of the calculated runoff reduction volume of 133 CF. The
bioretention basin meets the requirements for separation between the groundwater
and the limiting layer. The separation is at a minimum 5-feet below the disturbed area.
Down Gradient
Down-gradient drainage features, properties, and structures were evaluated within a
¼ mile of the project site. Any excess stormwater that could potentially leave the site
would not adversely impact or damage any down gradient properties or structures.
No down gradient drainage features will be impacted by the post-developed runoff.
Runoff leaving the site will be released at approximately the same rate as pre-
developed conditions due to the capacity and performance of the bioretention basin.
If the bioretention basin was to overflow, the runoff will spill to the northwest with basin
B drainage flow patterns.
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Storage
Bioretention Basin calculations were performed for the proposed project and were
determined to be adequate at conveying the 25- year storm event. The following table
shows the required and provided bioretention basin area. According to the analysis,
the bioretention basin can provide enough storage without overflowing for a 25-year
24-hour storm event. Refer to the attachments for additional calculations.
Table 4: Bioretention Storage Analysis - 25 Year Storm
Treatment
Depth (FT)
Provided
Pond Bottom
Area (SF)
Provided
Storage Area
(CF)
Required
Storage
Area (CF)
1.0 140 282.50 215.31
Operations and Maintenance
The stormwater system described above will function with relatively little oversight.
The proposed stormwater facilities will be operated and maintained by the property
owner. Routine maintenance includes inspections of the facilities, removing any
debris or vegetation impeding stormwater flow, and cleaning debris out of bioretention
basin and ditch.
S23-021-07
BASIN CHARACTERISTICS - CURVE NUMBER
Weighted
Curve Number
(sf) (acre) (sf) (sf) (sf) (sf) (sf)"CN" (1)
Pre A 26,232 0.60 0 0 0 0 26,232 48
Totals 26,232 0.60 0 0 0 0 26,232 48
Post A 26,232 0.60 432 256 2,640 421 22,483 53
Totals 26,232 0.60 432 256 2,640 421 22,483 53
NOTES:
(1)Group B Soils Runoff Curve Numbers
98 Paved parking lots, roofs, driveways, etc.
85 Gravel
61 Open Space, Grass
48 Brush; Good - >75% Ground Cover
(2)All remaining undisturbed area
S 8.781561
Recurrence
Interval 2-yr 10-yr 25-yr 100-yr
24-Hour
Precipitation
Depth (inches)1.18 1.7 1.96 2.34
P-2S -16.38 -15.86 -15.60 -15.22
*Use Rational Method to size flow control since P-2S<0
Roofs
Concrete &
Pavement Gravel
Swale /
Ditch
Brush,
Fair
Total Basin
Basin Area
S23-021-07
BASIN CHARACTERISTICS - RATIONAL METHOD
Weighted 2-Year 10-Year 25-Year 100-Year
Average Peak Flow Peak Flow Peak Flow Peak Flow
(sf) (acre) (sf) (sf) (sf) (sf) (sf)"C" (1)(cfs) (2)(cfs) (2)(cfs) (2)(cfs) (2)
Pre A 26,232 0.60 0 0 0 0 26,232 0.25 0.04 0.06 0.07 0.09
Totals 26,232 0.60 0 0 0 0 26,232 0.25 0.04 0.06 0.07 0.09
Post A 3,775 0.09 432 256 2,640 447 0 0.53 0.01 0.02 0.02 0.03
Onsite Basin A Total 3,775 0.09 432 256 2,640 447 0 0.53 0.01 0.02 0.02 0.03
Post B 22,483 0.52 0 0 0 0 22,483 0.25 0.03 0.05 0.06 0.08
Offsite Basin B Total 22,483 0.52 0 0 0 0 22,483 0.25 0.03 0.05 0.06 0.08
Total Impervious Area: 3,328 sf
1st 1/2 Inch from Impervious Area:139 cf
Slope (%) Distance (ft) n t1 (min)Slope (%) Distance (ft) n t2 (min)Velocity (fps) Distance (ft)
t3 (min)
Tc(4) Total
(min)
Post BASINA 0.01 110 0.011 2.15 0.00 260 0 0.00 0.00 0.00 0.00 2.15
Post BASINB 0.00 0 0.011 0.00 0.02 260 0.13 30.91 0.00 0.00 0.00 30.91
Notes:
(1)Runoff Coefficients, "C":
0.90 Paved parking lots, roofs, driveways, etc.
0.50 Gravel
0.25 Pasture/Undeveloped, Good Condition
0.15 Pasture/Undeveloped, Mowed
0.10 Open Space, Landscaped
(2)Rational Method Calculations, Q=C x I x A
Based on MDT's Appendix A - Rainfall Depths & Intensities (Bozeman Gallatin FLD)
Freq Tc I (in/hr)
2-yr 2 hr 0.240
10-yr 2 hr 0.410
25-yr 2 hr 0.490
100-yr 2 hr 0.610
(3)Time of Concentration Equations:
Sheet Flow: Shallow/Gutter Flow: Open Channel / Pipe Flow
(4)Minimum Time of Concentration is 5 minutes.
Basin Area
Overland Flow Range (natural) Pipe Flow
TIME OF CONCENTRATION(2)
Total Basin
Roofs
Concrete &
Pavement Gravel
Swale /
Ditch
Open
Space
= Input
= Equation
Runoff Reduction Volume (RRV)
RRV = PRvA/12
P Water quality rainfall depth (0.5 inches) 0.5 Inches
Rv Runoff Coefficient (Rv=0.05 + 0.9(I)) 0.84
I Percent impervious cover draining to facility, converted to decimal form 0.88
A Site drainage area in acres 0.09 Acres (Improved Area Only)
RRV =0.0030 Acre-ft 133 CF
Runoff Treatment Volume (RTV)
RTV = RRV - Vi,e,c
Vi,e,c Volume of water infiltrated, evapotranspired, or captured for reuse onsite -0.0004 Acre-ft
RTV = 0.0000 Acre-ft
Runoff Treatment Flowrate (RTF)
Peak discharge from exhibit 4-i or 4-ii
1000
CN
99.27
P Water quality rainfall depth (0.5 inches) ` 0.5 Inches
Q RRV*12/A 0.42 Inches
Ia = 0.01
P 0.5 Inches 0.5
Ia/P 0.03
qu Peak discharge from exhibit 4-i or 4-ii 500 cfs/mi^2/inch
RTF = quAQ
qu Unit Peak Discharge 500 cfs/mi^2/inch
A Drainage Area (mi^2) 0.0001 mi^2
Q Runoff Depth ` 0.42 inches
RTF= 0.03 CFS
S23-021-07 - Water Quality Design
Ia = 0.2*( -10)
CN =1000
10+5P+10Q-10(Q^2+1.25QP)^.5
Bioretention Basin Calculations
Surface Ponding Area
SPv = Minimum Surface Ponding Volume = 0.5-inch Rainfall Event 139 CF
dp = Design ponding depth 1 FT
SAp = SPv/dp 139 SF
Provided Pond Bottom Area (SF) 140 SF
Provided Pond Storage Area (SF) 320 SF
Provided Pond Storage Area (CF) 230 CF
Filter Bed
Af = Surface Area of Filter Bed (SF) = Pond Bottom Area 140 SF
Vwq = Runoff Treatment Volume (CF) = RRV 133 CF
df = Filter Bed Depth (ft) 1.5 FT (18 inches minimum)
k = coefficient of permeability of filter media (ft/day) 0.5 ft/day
hf = average height of water above filter bed (ft) 0.95 ft
tf = design filter bed drain time (days)
tf = Vwq * df 1.16 days
k*(hf + df)*Af
Bioretention Soil Media - Storage Volume
BSMv = Bioretention soil media storage volume (CF) 52.5 CF
SAb = Bottom surface area of BSM and Aggregate Layer (SF) 140 SF
dbsm = Depth of bioretention soil = df 1.5 FT
nbsm = Effective porosity of BSM 0.25
Underdrain Aggregate Layer Storage
ALv = Aggregate Layer Storage Volume (CF) 0 CF
SAb = Bottom surface area of BSM and Aggregate Layer (SF) 140 SF
dAL = Depth of Aggregate Layer (ft) 0 FT
nAL = Effective porosity of AL 0.4
Bioretention Area Total Storage Volume
Dv = SPv+BSMv + Alv 282.5 CF
100-Year Drawdown Time for Bioretention Basin
Infiltration Only as Vstorm is less than Pond Volume
Qp = 0.03 cfs
Tc = 5.00 min
V = 1.34*Qp*t 11 CF
Depth = 1.0 Inches
Infiltration =1.00 in/hr 1.0 hr
Total Basin Volume for Emergency Overflow
Pond Bottom Area 140 SF
Pond Top Area 221 SF
Pond Depth 1 FT
Pond Overflow Volume 180.5 CF
Drywell Volume 0 CF
Total Storage Volume without Overflowing 180.5 CF
Storage Required
Tc Time inc. Q dev. V in V outhrsec(cfs)(cu. Ft.) (cu. Ft.)
2 YR 2 7200 0.24 0.01 105.46 0 105.46 282.5
10 YR 2 7200 0.41 0.02 180.16 0 180.16 282.5
25 YR 2 7200 0.49 0.02 215.31 0 215.31 282.5
100 YR 2 7200 0.61 0.03 268.04 0 268.04 282.5
Intensity
(in./hr.)
Storage
Required
Storage
Provided
Hydrology 9B-6
Hydraulics Manual January 2022
Station
Information
Storm
Duration
Depth at Selected Recurrence Intervals (inches) Intensity at Selected Recurrence Intervals (inches/hour)
2-yr 5-yr 10-yr 25-yr 50-yr 100-yr 2-yr 5-yr 10-yr 25-yr 50-yr 100-yr
Boulder 5-min 0.17 0.24 0.29 0.35 0.40 0.44 2.05 2.92 3.49 4.22 4.76 5.29 COOP: 241008 10-min 0.25 0.36 0.43 0.51 0.58 0.65 1.50 2.13 2.56 3.09 3.48 3.87
Elev: 4,882 ft 15-min 0.30 0.43 0.52 0.63 0.71 0.79 1.22 1.73 2.07 2.50 2.82 3.14
Modified POR: 58 20-min 0.32 0.46 0.55 0.67 0.75 0.84 0.97 1.39 1.66 2.01 2.26 2.52
Type: 2nd Order 25-min 0.35 0.49 0.59 0.71 0.80 0.89 0.83 1.18 1.41 1.71 1.93 2.14
30-min 0.37 0.52 0.62 0.75 0.85 0.95 0.73 1.04 1.25 1.51 1.70 1.89
35-min 0.38 0.54 0.64 0.77 0.87 0.97 0.65 0.92 1.10 1.33 1.50 1.67
40-min 0.39 0.55 0.66 0.79 0.90 1.00 0.58 0.82 0.99 1.19 1.34 1.50
45-min 0.40 0.56 0.67 0.81 0.92 1.02 0.53 0.75 0.90 1.09 1.22 1.36
50-min 0.40 0.57 0.69 0.83 0.93 1.04 0.48 0.69 0.82 0.99 1.12 1.25
55-min 0.41 0.58 0.70 0.84 0.95 1.06 0.45 0.64 0.76 0.92 1.04 1.15
1-hr 0.42 0.59 0.71 0.86 0.97 1.08 0.42 0.59 0.71 0.86 0.97 1.08
2-hr 0.51 0.70 0.83 1.00 1.12 1.24 0.25 0.35 0.42 0.50 0.56 0.62
3-hr 0.56 0.77 0.91 1.08 1.21 1.34 0.19 0.26 0.30 0.36 0.40 0.45
6-hr 0.71 0.92 1.06 1.23 1.36 1.49 0.12 0.15 0.18 0.21 0.23 0.25
12-hr 0.88 1.13 1.30 1.52 1.68 1.83 0.07 0.09 0.11 0.13 0.14 0.15
24-hr 1.07 1.37 1.57 1.82 2.01 2.20 0.045 0.057 0.065 0.076 0.084 0.091
Bozeman Airport 5-min 0.17 0.26 0.32 0.40 0.45 0.51 2.08 3.16 3.87 4.76 5.43 6.09 COOP: 240622 10-min 0.25 0.38 0.47 0.58 0.66 0.74 1.53 2.31 2.83 3.48 3.97 4.45
Elev: 4,459 ft 15-min 0.31 0.47 0.57 0.71 0.81 0.90 1.24 1.87 2.29 2.83 3.22 3.61
Modified POR: 40 20-min 0.33 0.50 0.61 0.75 0.86 0.96 0.99 1.50 1.84 2.26 2.58 2.89
Type: 2nd Order 25-min 0.35 0.53 0.65 0.80 0.92 1.03 0.84 1.28 1.56 1.93 2.20 2.46
30-min 0.37 0.56 0.69 0.85 0.97 1.09 0.75 1.13 1.38 1.70 1.94 2.18
35-min 0.38 0.58 0.71 0.87 1.00 1.12 0.66 0.99 1.22 1.50 1.71 1.92
40-min 0.39 0.59 0.73 0.90 1.02 1.15 0.59 0.89 1.09 1.35 1.53 1.72
45-min 0.40 0.61 0.75 0.92 1.05 1.18 0.54 0.81 1.00 1.23 1.40 1.57
50-min 0.41 0.62 0.76 0.94 1.07 1.20 0.49 0.74 0.91 1.12 1.28 1.44
55-min 0.42 0.63 0.77 0.95 1.08 1.22 0.45 0.69 0.84 1.04 1.18 1.33
1-hr 0.42 0.64 0.79 0.97 1.10 1.24 0.42 0.64 0.79 0.97 1.10 1.24
2-hr 0.49 0.68 0.81 0.98 1.10 1.22 0.24 0.34 0.41 0.49 0.55 0.61
3-hr 0.56 0.74 0.86 1.01 1.12 1.23 0.19 0.25 0.29 0.34 0.37 0.41
6-hr 0.71 0.88 0.99 1.14 1.24 1.35 0.12 0.15 0.17 0.19 0.21 0.22
12-hr 0.91 1.12 1.26 1.43 1.56 1.69 0.08 0.09 0.10 0.12 0.13 0.14
24-hr 1.18 1.49 1.70 1.96 2.15 2.34 0.049 0.062 0.071 0.082 0.090 0.098
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
October 24, 2024
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 (Bozeman, MT - IIG)..............................................................................9
Legend................................................................................................................10
Map Unit Legend (Bozeman, MT - IIG)...............................................................11
Map Unit Descriptions (Bozeman, MT - IIG).......................................................11
Gallatin County Area, Montana.......................................................................13
450C—Blackdog-Quagle silt loams, 4 to 8 percent slopes.........................13
References............................................................................................................16
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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
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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
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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 (Bozeman, MT - IIG)50614405061450506146050614705061480506149050615005061510506152050615305061440506145050614605061470506148050614905061500506151050615205061530496230 496240 496250 496260 496270 496280 496290 496300
496230 496240 496250 496260 496270 496280 496290 496300
45° 42' 26'' N 111° 2' 54'' W45° 42' 26'' N111° 2' 50'' W45° 42' 23'' N
111° 2' 54'' W45° 42' 23'' N
111° 2' 50'' WN
Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 12N WGS84
0 20 40 80 120
Feet
0 5 10 20 30
Meters
Map Scale: 1:498 if printed on A portrait (8.5" x 11") 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 28, Aug 22, 2024
Soil map units are labeled (as space allows) for map scales
1:50,000 or larger.
Date(s) aerial images were photographed: Aug 18, 2022—Aug
29, 2022
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.
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Map Unit Legend (Bozeman, MT - IIG)
Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI
450C Blackdog-Quagle silt loams, 4
to 8 percent slopes
0.6 100.0%
Totals for Area of Interest 0.6 100.0%
Map Unit Descriptions (Bozeman, MT - IIG)
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
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.
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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
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
Depth to restrictive feature:More than 80 inches
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 content:30 percent
Available water supply, 0 to 60 inches: High (about 10.9 inches)
Interpretive groups
Land capability classification (irrigated): 3e
Land capability classification (nonirrigated): 3e
Hydrologic Soil Group: C
Ecological site: R044BB032MT - Loamy (Lo) LRU 01 Subset B
Hydric soil rating: No
Description of Quagle
Setting
Landform:Stream terraces
Down-slope shape:Linear
Across-slope shape:Linear
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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
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 content:35 percent
Maximum salinity:Nonsaline to very slightly saline (0.0 to 2.0 mmhos/cm)
Available water supply, 0 to 60 inches: High (about 10.8 inches)
Interpretive groups
Land capability classification (irrigated): 4e
Land capability classification (nonirrigated): 4e
Hydrologic Soil Group: B
Ecological site: R044BB030MT - Limy (Ly) LRU 01 Subset B
Hydric soil rating: No
Minor Components
Beanlake
Percent of map unit:5 percent
Landform:Alluvial fans, stream terraces
Down-slope shape:Linear
Across-slope shape:Linear
Ecological site:R044BB030MT - Limy (Ly) LRU 01 Subset B
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:R044BB032MT - Loamy (Lo) LRU 01 Subset B
Hydric soil rating: No
Anceney
Percent of map unit:2 percent
Landform:Stream terraces
Down-slope shape:Linear
Across-slope shape:Linear
Ecological site:R044BB036MT - Droughty (Dr) LRU 01 Subset B
Hydric soil rating: No
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Custom Soil Resource Report
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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
16
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
Custom Soil Resource Report
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1 OF 1PRE-DEVELOPED BASIN MAP BASIN A NPGIS AREA= 26,232 SFTOTAL AREA= 26,232 SFTc=260 LFSHEETDESIGNED BY:QUALITY CHECK:JOB NO.FIELDBOOKDRAWN BY:DATE:REV DATE REVISION NOT FORCONSTRUCTION
INTERMOUNTAIN INFRASTRUCTURE GROUP
BOZEMAN, MONTANA
S23-021-0712/17/2024LAMSNMDAPEngineering
303 EAST 2ND AVE. • SPOKANE, WASHINGTON 99202
509.622.2888 • tdhengineering.com AG NN PORONALE FESSIANTMOR
INEE
PERMIT SET - NOT FOR CONSTRUCTIONLEGENDMAJOR EXISTINGCONTOURMINOR EXISTINGCONTOURTIME OF CONCENTRATION (TOC)LEASE LOT AREA
1 OF 1POST-DEVELOPED BASIN MAPSHEET DESIGNED BY:QUALITY CHECK:JOB NO.FIELDBOOKDRAWN BY:DATE:REV DATE REVISION NOT FORCONSTRUCTION
INTERMOUNTAIN INFRASTRUCTURE GROUP
BOZEMAN, MONTANA
S23-021-0712/17/2024LAMSNMDAPEngineering
303 EAST 2ND AVE. • SPOKANE, WASHINGTON 99202
509.622.2888 • tdhengineering.com AG NN PORONALE FESSIANTMOR
INEE
PERMIT SET - NOT FOR CONSTRUCTIONBASIN B NPGIS AREA= 22,483 SFTOTAL AREA= 22,483 SFTc=260 LFLEGENDMAJOR EXISTINGCONTOURMINOR EXISTINGCONTOURTIME OF CONCENTRATION (TOC)LEASE LOT AREABASIN A ROOF AREA= 432 SFCONCRETE AREA= 256 SFGRAVEL AREA= 2640 SFSWALE/DITCH AREA = 447 SFTOTAL AREA= 3,775 SFTc=110 LF