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Project Development Plan (PDP)
Preliminary Drainage Report
For
Montava Subdivision Phase D
May 1, 2024
submitted to:
City of Fort Collins,
Colorado
748 Whalers Way
May 1, 2024
Mr. Wes Lamarque
City of Fort Collins
Development Review Engineer
700 Wood Street
Fort Collins, CO 80521
Re: Montava Subdivision Phase D
Final Design Drainage Report
Project No. 1230.0005.00
Dear Mr. Lamarque:
TST, Inc. Consulting Engineers (TST) is pleased to submit this Preliminary
Design Drainage Report for the Montava Subdivision Phase D project to the
City of Fort Collins (City) for review and approval.
The purpose of this drainage report is to evaluate the drainage conditions of the
above-referenced proposed Montava Subdivision Phase D project site. The Fort
Collins Stormwater Criteria Manual (referred to as FCSCM).
Please review the attached report and provide any questions or comments at your
earliest convenience. We appreciate the opportunity to be of continued service to
the city and look forward to receiving your comments and moving forward on this
important project.
Sincerely,
TST, INC. CONSULTING ENGINEERS
Bryston Anthony M. Gartner, E.I. Derek A. Patterson, P.E.
BAMG DAP
I hereby attest that this report for the preliminary drainage design for the Montava
Subdivision Phase D was prepared by me or under my direct supervision, in
accordance with the provisions of the Fort Collins Stormwater Criteria Manual. I
understand that the City of Fort Collins does not and will not assume liability for
drainage facilities designed by others.
______________________________
Derek A. Patterson
Registered Professional Engineer
State of Colorado No. 48898
748 Whalers Way
Suite 200
Fort Collins, CO 80525
970.226.0557 main
970.226.0204 fax
ideas@tstinc.com
www.tstinc.com
Table of Contents
Preliminary Design Drainage Report
Montava Subdivision Phase D
Page i
1.0 - GENERAL LOCATION AND DESCRIPTION ......................................................... 1
1.1 Project Location and Description ................................................................... 1
1.2 Description of Property ................................................................................... 2
2.0 - DRAINAGE BASINS AND SUB-BASINS .............................................................. 4
2.1 Major Basin Description .................................................................................. 4
2.2 Existing Conditions ......................................................................................... 4
2.3 Proposed Conditions ...................................................................................... 4
3.0 - DRAINAGE DESIGN CRITERIA ............................................................................ 9
3.1 Hydrological and Hydraulic Criteria ............................................................... 9
4.0 - CONCLUSIONS .................................................................................................... 11
5.0 - REFERENCES ...................................................................................................... 13
6.0 - APPENDICES ....................................................................................................... 14
List of Figures
1.1 Vicinity Map ..................................................................................................................... 2
Montava Subdivision Phase D Preliminary Drainage Report
Page 1
1.0 - General Location and Description
The purpose of this Preliminary Drainage Report is to present the drainage design for the
Montava Subdivision Phase D (Hereinafter referred to as the “Phase D”) project site to the
City of Fort Collins (hereinafter referred to as the “City”) for review and approval.
The design objectives for this drainage report are to present:
Hydrologic analysis of the proposed improvements and surrounding off-site areas to
determine the location and magnitude of the site’s storm runoff.
Hydrologic data used to design storm runoff collection and conveyance facilities.
Hydraulic analysis of proposed on-site and existing downstream storm infrastructure to
ensure sufficient conveyance of stormwater runoff to the proposed detention areas.
Detention analysis and design of the proposed stormwater detention areas.
Best Management Practices (BMPs) are used to prevent erosion and sedimentation
before, during, and after construction of the stormwater infrastructure.
Overall storm drainage plan that meets previously approved drainage plans and the
FCSCM.
The drainage system was designed using the Fort Collins Stormwater Criteria Manual
(collectively referred to as FCSCM).
1.1 Project Location and Description
The Phase D project site is located in Section 32, Township 8 North, Range 68 West of the 6th
Principal Meridian, within the City of Fort Collins, Larimer County, Colorado. The proposed site
is bounded on the north by farmland, Future Montava Subdivision phases, and Richards Lake
Road. On the east by farmland, N. Giddings Road, and Future Montava Subdivision phases. On
the south by farmland and Mountain Vista Drive. On the west by farmland, the Number 8 Outlet
Ditch, and Future Montava Subdivision phases. A vicinity map illustrating the project location is
provided in Figure 1.1.
Montava Subdivision Phase D Preliminary Drainage Report
Page 2
Figure 1.1: Vicinity Map
1.2 Description of Property
The Phase D project site contains approximately 58 acres and consisting of the Single-Family
and Open Space. Phase D is currently zoned as Mixed Density Neighborhood.
According to Flood Insurance Rate Map (FIRM) #08069C0982F eff. 12/19/2006 prepared by the
Federal Emergency Management Agency (FEMA), Phase D is located in unshaded Zone X.
Zone X indicates areas determined to be outside of 500-year or 0.2% annual chance floodplain,
meaning it is not designated as a special flood hazard zone. Copies of the FEMA maps that
apply to Phase D are included in Appendix B.
The types of soils found on the Montava Subdivision Phase D site consist of:
Aquepts, loamy (5).
Fort Collins loam (35) – 0 to 3 percent slopes.
Fort Collins loam (36) – 3 to 5 percent slopes.
Satanta loam (95) – 1 to 3 percent slopes.
Montava Subdivision Phase D Preliminary Drainage Report
Page 3
Satanta Variant clay loam (98) – 0 to 3 percent slopes.
The characteristics of the soil found on the project site include:
Slow to very slow infiltration rate when thoroughly wet.
Slow to very slow rate of water transmission.
Majority of the site has a wind erodibility rating of 5 and 6 (8 being the least susceptible)
These soils consist of the following hydrologic soil groups as defined in the United States
Department of Agriculture (USDA), Web Soil Survey:
Group C – 38.90%.
Group D – 61.10%.
The USDA web soil survey report is included in Appendix C.
The following reports were utilized in the drainage analysis and design of Phase D.
Montava Master Drainage Study Fort Collins, Colorado, prepared by Martin/Martin, Inc.,
dated January 23, 2019.
Hydrologic and hydraulic information was referenced from this report to analyze off-site
areas and conveyance links downstream from Phase D and site.
Montava Subdivision Phase D Preliminary Drainage Report
Page 4
2.0 - Drainage Basins and Sub-Basins
2.1 Major Basin Description
According to the FCSCM, Phase D is located within the Upper Cooper Slough Basin. The Upper
Cooper Slough Basin stormwater generally flows from north to south which is ultimately being
captured by the Larimer and Weld Canal. According to the Montava Master Drainage Study,
Phase D is primarily located in Basin D, Basin F, and Basin G1. Generally, Basin D, Basin F,
and Basin G1all drain from the northwest to the southeast and eventually end up in the Larimer
and Weld Canal.
2.2 Existing Conditions
The Phase D site is located in an undeveloped plot of land west of the Anheuser Busch
property. The current land is undeveloped and used for agricultural purposes. The land currently
consists of native grasses, bare ground, and crops. Phase D sheet flows southeast into an
inadvertent detention area which will overtop Mountain Vista Drive, in a larger storm event, and
eventually into the Larimer and Weld Canal through various existing drainage infrastructure. The
existing site does not have any existing ponds or drainage facilities. The site has an inadvertent
detention area near Giddings Road and Mountain Vista Drive. The major drainage way that is
being utilized for Phase D is the Larimer and Weld Canal.
2.3 Proposed Conditions
The proposed Phase D development generally maintains existing drainage patterns. Phase D is
located in three basins, outlined in the Montava Master Drainage Plan. Phase D is located in
Basin D, Basin F, and Basin G1. The portion of Phase D located in Basin D will generally flow
west and south into an irrigation/ storm pond (Pond D Montava Master Drainage Plan). The
portion of Phase D located in Basin F will generally flow southwest into a temporary storm
infrastructure swale that outfalls into Interim Pond 427. The portion in Basin F will eventually be
captured and detained by Pond F, constructed with Montava Subdivision Phase E. The portion
of Phase D located in Basin G1 will generally flow south and east into Interim Pond 427. This
portion of Phase D will eventually be detained in Pond 426 (southwest of the site).
The following basins were delineated for the Montava Subdivision Phase D site plan, using the
Montava Master Drainage Basins:
Basin D (D1-D13)- Basin D, within Phase D, is made up of mixed density single family lots,
streets, and open space. Basin D, within Phase D, is approximately 11.98 acres with a
composite imperviousness of approximately 64.3%. Basin D was subdivided into 13 subbasins
that have their own drainage patterns. Generally, the subbasins runoff starts from the single-
family development and drains into street or alleys and into storm lines via curb inlets or area
Montava Subdivision Phase D Preliminary Drainage Report
Page 5
inlets and into Pond D. Basin D water quality will be treated in Pond D and/or a rain garden
located in the center of the basin. Due to space constraints, we are proposing that the majority
of the water quality to be treated in Pond D. This is not a traditional LID, but we believe that
Pond D provides a higher degree of stormwater quality treatment than a standard stormwater
quality pond due to it being a wet pond that has additional volume below the detention . Another
proposed LID is a rain garden located in the center of the basin. Once the runoff has been
treated in the rain garden it will be conveyed into Pond D.
Basin F (F1- F26) – Basin F, within Phase D, is made of mixed density single family lots,
streets, future apartments, and open space. Basin F, within Phase D, is approximately 24.48
acres with a composite imperviousness of approximately 68.7%. Basin F was subdivided into 26
subbasins that have their own drainage patterns. Generally, the subbasins runoff starts in the
single-family lots and sheet flows into the street or alleys and into proposed storm lines via curb
inlets or area inlets that discharge into the interim swale that borders the southwest portion of
the site. In the master drainage plan this portion of Phase D will be detained in Pond F, not
being constructed with Phase D. Basin F will be treated in two different rain gardens and in the
future will be treated by underground water quality and, in the interim condition, in the interim
swale that discharges into Interim Pond 427. In the full build out, future condition, the rain
gardens will discharge into the future Pond F.
Basin G (G1-1 –10) – Basin G, within Phase D, is made of mixed density single family lots,
streets, future apartments, and open spaces. Basin G, within Phase D, is approximately 13.86
acres with a composite imperviousness of approximately 76.5%. Basin G was subdivided into
10 subbasins that have their own drainage patterns. Generally, the subdivision runoff starts in
the single-family lots and sheet flows into the streets or alleys and into proposed storm line via
curb inlet or area inlets that discharges into the interim swale that borders the southwest portion
of the site and into Interim Pond 427. In the master drainage plan Interim Pond 427 will be
turned into a conveyance channel to future pond 426. Basin G will have no proposed LID
treatment. The future apartment sites will have to provide their own LID treatment and is not
included in the LID calculations.
Future Basin (1-3) - Future Basin is approximately 25.23 acres with a composite
imperviousness of approximately 60.00%. Future Basins were subdivided into 3 subbasins that
have their own drainage patterns. Basin Future – 1 and Future – 2 will have future street,
proposed single-family lots, and a proposed drainage channel. The proposed drainage channel
will act as LID and will be an interim pond to attenuate future and offsite flows. Basin Future – 3
will have future streets, future single-family lots. Future -1 and Future -2 water quality will be
provided in the large interim drainage swale. Future-3 will have to provide their own LID
treatment and are not included in the LID calculations. In the interim conditions Future 1 and 2
will be detained and attenuated in the proposed drainage swale/ Interim Pond. Future -3 drains
directly into the Interim Pond 427.
School Site- Basin School is approximately 18.47 acres with a composite imperviousness is
Montava Subdivision Phase D Preliminary Drainage Report
Page 6
approximately 60%. Basin School is for the future school site and future amenities. Basin
School drains from the northwest of the basin to the southeast portion of the site where it is
collected by a proposed storm sewer of Phase D and routed to Pond D. Basin School will have
to provide their own LID treatment and was not included with the LID calculations.
Pond D Basin- Pond D Basin is approximately 7.48 acres with a composite imperviousness of
20.00%. Pond D Basin consists of proposed amenities and the entirety of pond D. All runoff
generated within Pond D Basin will sheet flow into the Pond. Pond D Basin water quality will be
treated in Pond D.
Pond 427 Basin- Pond 427 Basin is approximately 10.12 acres with a composite
imperviousness of 2.00%. Pond 427 Basin consists of an interim drainage channel and an
interim Pond. All runoff in this basin will sheet flow directly into the drainage channel or the
interim pond. This basin is treated within the interim drainage channel. Once treated in the
drainage swale the runoff will go into Pond 427.
Off-Site Basins
Offsite 1- Offsite 1 Basin is approximately 103.82 acres and will not have any improvements
within it. Offsite 1 contains all the undeveloped land that is north of Phase D between Giddings
Road, The number 8 ditch, and Richards Lake Road. All calculations that involve Offsite 1 will
be done with the interim undeveloped condition. In the future when this basin is developed each
separate phase will have a drainage report and ponds that will more closely match the master
drainage plan. The proposed condition will capture all the runoff from the north into the drainage
channel and run it as close to existing conditions and will outfall south of Mountain Vista drive.
Offsite 2- Offsite 2 Basin is approximately 70.35 acres and will not have any improvements
within it. Offsite 2 contains all the undeveloped land that is south of Phase D between Interim
Pond 427, Number 8 Ditch and Mountain Vista Drive. No calculations were made using runoff
from Offsite 2. Offsite 2 follows existing drainage patterns where runoff from the basin sheet
flows south into an spot near Mountain Vista Drive (inadvertent detention) and overtops the road
in large storm events. In the future when this basin is developed each phase will have a
drainage report and ponds that will attenuate the runoff as described in the master drainage
report.
In the future Phase D will only be receiving runoff from the school site. All other basins will be
following the master drainage plan and will have their own drainage reports that shows
conformance with the master drainage plan.
2.4 Low Impact Development (LID)
Per City of Fort Collins criteria, Low Impact Development (LID) features are proposed to treat
50% of the newly developed Single-Family, and 75% of the newly developed Multi-family within
Phase D.
Montava Subdivision Phase D Preliminary Drainage Report
Page 7
Three LID systems are being proposed for Phase D, Rain Gardens, and Wet Pond. One LID
system will be used in the future for Phase D, Underground detention chambers (StormTech
Chambers). The percentage of newly developed areas treated by these systems is included in
Appendix B.
The proposed LID systems, water quality, and detention facilities will be located in tracts owned
and maintained by the Montava Metropolitan District.
2.5 MDCIA “Four Step Process”
Step 1 – Employee Runoff Reduction Practices
Montava Phase D provides LID treatment for 50% of the single-family development and 75% of
the multifamily development, through various systems (Raingardens, Wet Ponds, and future
Underground detention chambers). The LID systems have been placed throughout the site to
minimize directly connected impervious areas.
Step 2 – Implement BMPs That Provide a WQCV with Slow Release
The remaining Single-Family and Multi-family development throughout the site not being treated
by the LID described is being treated through traditional water quality control volume extended
drainage basins designed to release the water quality event within a minimum if 40 hours.
Step 3 – Stabilize Streams
Portions of Phase D will be spilling into a temporary swale that will connect Pond D with Interim
Pond 427. Phase D will be spilling into a couple of ponds that will reduce the sediment load to
the downstream open irrigation channel.
Step 4 – Implement Site Specific and Other Source Control BMPs
1. The following practices suggested by City of Fort Collins Criteria will be implemented
throughout the design and construction process:
2. Being a single-family development, trash receptacles will be dispersed throughout the
neighborhood and likely be enclosed containers that minimize concentrated and polluted
runoff from entering the storm sewer system or receiving drainageways prior to being
treated.
3. Phase D of Montava Subdivision does not include a dog park, but any future dog parks
shall be located in areas away from detention basins and educational opportunities to
reinforce pick-up practices for dog owners shall be employed.
4. Phase D of Montava Subdivision does not include any community gardens, but future
community gardens shall be located in areas that are outside of the detention basins to
Montava Subdivision Phase D Preliminary Drainage Report
Page 8
prevent chemical and sediment loading.
5. Construction Best Management Practices (BMPs) will be employed to located material
storage away from drainage facilities.
2.6 Variance Requests
No drainage variances are being requested at this time.
Montava Subdivision Phase D Preliminary Drainage Report
Page 9
3.0 - Drainage Design Criteria
The drainage design presented in this report has been developed in accordance with the
guidelines established by the FCSCM dated December 2018.
Storm system infrastructure including pipes, culverts, inlets, and drainage swales will be sized to
convey the 100-year storm event. In areas of concern, storm system infrastructure will sized to
handle the 100-year and any additional bypass flow from upstream infrastructure.
3.1 Hydrological and Hydraulic Criteria
Design Rainfall & Runoff Calculation Method
The hydrology of the project site for developed conditions will be evaluated based on the 2-, 10-
and 100-year storm frequencies as dictated within the FCSCM manual. The Rational Method
was used to determine peak runoff rates for each developed basin. Peak storm runoff values
will be used to size on-site drainage facilities including storm culverts, sewers, inlets and
channels for the initial and major design storms as specified in the FCSCM criteria and
standards. Within the criteria and standards, the initial design storm was established as the 2-
year minor storm event and the 100-year storm as the major event.
Inlet Design
All inlets within the project area will be designed to collect and convey the 2-year developed
runoff. In areas where flooding is a concern, inlets were upsized to convey as much of the 100-
year developed runoff as possible. As stated in FCSCM, Inlet Functions, Types and Appropriate
Applications, the standard inlets for use on City of Loveland streets are:
Inlet Type Permitted Use
Curb Opening Inlet Type R All street types with 6 inches of vertical curb
Type 13 Inlet with Valley Grate All alleys with reverse crown
Storm Sewer and Culvert Design
As stated in the FCSCM, the Manning’s roughness coefficient (n) for all storm sewer pipe
capacity calculations shall be 0.013 regardless of pipe material.
The storm sewers and culverts in the project area will be designed in accordance with the
criteria and standards of the FCSCM using a minimum pipe diameter of 15 inches. Where
applicable, storm sewers will be sized to convey the 100-year developed runoff to the existing
detention ponds. Peak runoff for storm sewer design was calculated using the Rational Method
Montava Subdivision Phase D Preliminary Drainage Report
Page 10
per the FCSCM. All storm sewers will be sized using the Urban Drainage program, UD-Sewer
2009 Version 1.4.0. All culverts will be sized using the Federal Highway Administration (FHA)
Program, HY-8 Version 7.30. For storm and culvert capacity calculations refer to Appendix G.
Street Capacity
The criteria and standards set forth in the FCSCM will be used to check street capacity for both
the minor (2-year) and major (100-year) storm events. The FCSCM requires that stormwater
overtopping curbs should not occur during the minor storms and the flow spread must meet the
following guidelines for each street designation:
Local, Alley – flow may spread to crown of road.
Collector (without median) - flow spread must leave a minimum of 6 feet (6’) wide
clear travel lane on each side of the centerline.
Arterial (with median) – flow spread must leave a minimum of 12 feet (12’) wide travel
lane in both directions of travel.
Additionally, the following allowable street flow depths were used for the drainage design:
Local, Alley – Minor Storm 0.50-ft depth at gutter, Major Storm 0.50-ft depth at crown
and 1.0-ft at gutter (most restrictive will apply)
Collector - Minor Storm 0.50-ft depth at gutter, Major Storm 0.50-ft depth at crown and
1.0-ft at gutter (most restrictive will apply)
Arterial (without median) - Minor Storm 0.50-ft depth at gutter, Major Storm 0.50-ft
depth at crown and 1.0-ft at gutter (most restrictive will apply)
Arterial (with median) - Minor Storm 0.50-ft depth at gutter, Major Storm not to exceed
bottom of gutter at median and 1.0-ft at gutter (most restrictive will apply)
Swale Design
As defined in Chapter 9 of the Fort Collins Stormwater Criteria Manual, open channels are
utilized to preserve, enhance, and restore stream corridors, used in the design of constructed
channels and swales by use of natural concepts.
Per the FCSCM criteria and standards, all open channels must be designed to carry the major
(100-year) storm runoff. The swales will be sized to either contain the 100-year developed peak
runoff plus 1 foot of freeboard or 133 percent of the 100-year developed peak runoff.
Drainage swales were designed to be grass-lined, triangular channels with 4:1 side-slopes.
Erosion potential in the swales will be analyzed to determine if additional protective measures
are needed within the project area based on Froude number calculations.
Montava Subdivision Phase D Preliminary Drainage Report
Page 11
Detention Discharge and Storage Calculation
Montava Phase D drains to three separate Detention/ Water Quality ponds. Pond D, Interim
Pond, and Interim Detention Pond 427.
Pond D is located in Pond D Basin and captures the runoff from Basin D, School Basin, and
Pond D Basin. This pond discharges into a swale that runs on the southwest border of the and
into Interim Pond 427. Pond D was sized with the SWMM model that was prepared with the
Montava Master Drainage Plan. In the master drainage plan the 100-year volume required is 9
ac-ft. An emergency spillway will be designed with this pond to spill south down the
embankment over Timberline Road and into a proposed interim channel/ future storm line. Pond
D is proposed to be an LID wet pond which will handle LID credits for Basin D. An interim Pond
is being proposed in the large swale that is north of the site. This pond was designed to handle
future basins as much offsite runoff as possible, the remaining offsite runoff will be bypass flow.
This interim pond will also act as LID for the road connection to Giddings and future basins. This
interim pond will discharge south into a proposed swale that flows to Interim Pond 427. Interim
Pond 427 was sized using a SWMM model that was prepared for the stormwater infrastructure
set that was submitted with Phase E. In the stormwater infrastructure set the 100-year volume
required the pond was designed for the entire surrounding area that includes Phase D, 18.7 ac-
ft. Interim Pond 427 will outfall to the east of Giddings Road and then south under Mountain
Vista Drive into an agricultural field and eventually into the L&W Canal.
Erosion and Sediment Control
Montava Phase D has been designed to be in compliance with the City of Fort Collins Erosion
Control Criteria and all Erosion Control Materials will be provided with the Final Drainage
Report. Erosion and sedimentation occurring on-site during construction will be controlled by the
use of temporary Best Management Practices (BMPs – i.e., silt fence, gravel inlet filters, vehicle
tracking control pads, and straw wattle barriers). A separate Stormwater Management Plan has
been provided with the PDR Submittal.
Montava Subdivision Phase D Preliminary Drainage Report
Page 12
4.0 - Conclusions
This preliminary drainage report has been prepared in accordance with the City of Fort Collins
Stormwater Criteria Manual for a Project Development Plan (PDP) submittal. The PDP plans
have also been prepared to be in compliance with the city’s current drainage criteria.
Phase D has been designed to safely and effectively capture, convey, and attenuate stormwater
runoff in accordance with the FCSCM, Fort Collins Stormwater Criteria Manual, and Montava
Master Drainage Study. 50% of the newly single-family development and 75% of the newly
developed multifamily development will be connected to a LID system, which will treat storms
before the traditional water quality and detention ponds. The traditional water quality and
detention ponds will treat the remaining development of the site. The proposed drainage
infrastructure will attenuate the flow prior to entering the downstream properties/ infrastructure.
Additionally, areas of future development adjacent to the project area will have to been analyzed
to ensure that adequate facilities will accommodate future development.
Montava Subdivision Phase D Preliminary Drainage Report
Page 13
5.0 - References
1. Fort Collins Stormwater Criteria Manual, as adopted by the city of Fort Collins, as
referenced in Section 26-500 of the Code of the City of Fort Collins, December 2018.
2. City of Fort Collins Cooper Slough Alternatives Analysis Update, prepared by Fort
Collins Department of Utilities, prepared by ICON Engineering Inc., October 2017
3. Montava Planned Unit Development Master Drainage Study, by Martin/Martin Inc., dated
January 23, 2019
Montava Subdivision Phase D Preliminary Drainage Report
Page 14
6.0 - Appendices
The following appendices are attached to and made part of this final drainage design report:
APPENDIX A HYDROLOGIC ANALYSIS
APPENDIX B LOW IMPACT DEVELOPMENT (LID) CALCULATIONS
APPENDIX C FEMA FLOOD INSURANCE RATE MAP
APPENDIX D USDA HYDROLOGIC SOIL GROUP MAP
APPENDIX E DRAINAGE PLANS
APPENDIX F DETENTION DESIGN
Appendix A
HYDOLOGIC ANALYSIS
MONTAVA SUBDIVISION PHASE D Preliminary Drainage Report
City of Fort Collins
IDF Curves
Duration 2-yr 10-yr 100-yr
5 2.85 4.87 9.95
6 2.67 4.56 9.31
7 2.52 4.31 8.80
8 2.40 4.10 8.38
9 2.30 3.93 8.03
10 2.21 3.78 7.72
11 2.13 3.63 7.42
12 2.05 3.50 7.16
13 1.98 3.39 6.92
14 1.92 3.29 6.71
15 1.87 3.19 6.52
16 1.81 3.08 6.30
17 1.75 2.99 6.10
18 1.70 2.90 5.92
19 1.65 2.82 5.75
20 1.61 2.74 5.60
21 1.56 2.67 5.46
22 1.53 2.61 5.32
23 1.49 2.55 5.20
24 1.46 2.49 5.09
25 1.43 2.44 4.98
26 1.40 2.39 4.87
27 1.37 2.34 4.78
28 1.34 2.29 4.69
29 1.32 2.25 4.60
30 1.30 2.21 4.52
31 1.27 2.16 4.42
32 1.24 2.12 4.33
33 1.22 2.08 4.24
34 1.19 2.04 4.16
35 1.17 2.00 4.08
36 1.15 1.96 4.01
37 1.13 1.93 3.93
38 1.11 1.89 3.87
39 1.09 1.86 3.80
40 1.07 1.83 3.74
41 1.05 1.80 3.68
42 1.04 1.77 3.62
43 1.02 1.74 3.56
44 1.01 1.72 3.51
45 0.99 1.69 3.46
46 0.98 1.67 3.41
47 0.96 1.64 3.36
48 0.95 1.62 3.31
49 0.94 1.60 3.27
50 0.92 1.58 3.23
51 0.91 1.56 3.18
52 0.90 1.54 3.14
53 0.89 1.52 3.10
54 0.88 1.50 3.07
55 0.87 1.48 3.03
56 0.86 1.47 2.99
57 0.85 1.45 2.96
58 0.84 1.43 2.92
59 0.83 1.42 2.89
60 0.82 1.40 2.86
From the City of Fort Collins Storm Drainage Design Criteria and Construction Standards
MONTAVA SUBDIVISION PHASE D Preliminary Drainage Report
From the Town of Timnath Design Criteria Manual and Construction Specifications
y = 2.5665e-0.021x
R² = 0.9519
y = 26.332x-0.53
R² = 0.9831
0.00
2.00
4.00
6.00
8.00
10.00
12.00
0 10 20 30 40 50 60 70
Ra
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I
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i
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Storm Duration (min)
City of Fort Collins IDF Curves
2-yr
10-yr
100-yr
Expon. (2-yr)
Power (100-yr)
MONTAVA SUBDIVISON PHASE D Preliminary Drainage Report
City of Fort Collins
Rational Method Runoff Coefficients
High Density 0.85 70
Lawn, Clayey, <2% Slope 0.20 2
Lawn, Clayey, >7% Slope 0.35 2
Lawn, Clayey, 2-7% Slope 0.25 2
Lawn, Sandy, <2% Slope 0.10 2
Lawn, Sandy, >7% Slope 0.20 2
Lawn, Sandy, 2-7% Slope 0.15 2
Low Denisty 0.55 30
Medium Density 0.65 50
Open Lands, Transition 0.20 20
Roofs 0.95 90
Streets: Gravel 0.50 40
Streets: Paved 0.95 90
Streets: Permeable Pavers 0.30 40
Urban Estate 0.30 30
From Table 3-3 of the City of Fort Collins, Stormwater Criteria Manual
Runoff
Coefficient Impervious
MONTAVA SUBDIVISION PHASE D Preliminary Drainage Report
Composite
C2 C2 C10 C100
Medium Density 0.00 0.65 50
Streets: Paved 0.77 0.95 90
Lawn, Clayey, >7% Slope 0.00 0.35 2
Medium Density 0.63 0.65 50
Streets: Paved 0.92 0.95 90
Lawn, Sandy, >7% Slope 0.00 0.20 2
Medium Density 1.02 0.65 50
Streets: Paved 0.36 0.95 90
Lawn, Clayey, >7% Slope 0.00 0.35 2
Medium Density 0.00 0.65 50
Streets: Paved 0.20 0.95 90
Lawn, Sandy, >7% Slope 0.00 0.20 2
Medium Density 0.00 0.65 50
Streets: Paved 0.20 0.95 90
Lawn, Sandy, >7% Slope 0.00 0.20 2
Medium Density 0.49 0.65 50
Streets: Paved 0.59 0.95 90
Lawn, Sandy, >7% Slope 0.00 0.20 2
Medium Density 1.38 0.65 50
Streets: Paved 0.65 0.95 90
Lawn, Clayey, >7% Slope 0.08 0.35 2
Medium Density 0.49 0.65 50
Streets: Paved 0.33 0.95 90
Lawn, Clayey, >7% Slope 0.78 0.35 2
Medium Density 0.36 0.65 50
Streets: Paved 0.14 0.95 90
Lawn, Clayey, >7% Slope 0.00 0.35 2
Medium Density 0.37 0.65 50
Streets: Paved 0.68 0.95 90
Lawn, Clayey, >7% Slope 0.00 0.35 2
Medium Density 0.00 0.65 50
Streets: Paved 0.35 0.95 90
Lawn, Clayey, >7% Slope 0.00 0.35 2
Medium Density 0.13 0.65 50
Streets: Paved 0.46 0.95 90
Lawn, Clayey, >7% Slope 0.00 0.35 2
Medium Density 0.17 0.65 50
Streets: Paved 0.44 0.95 90
Lawn, Clayey, >7% Slope 0.00 0.35 2
BASIN D TOTAL 11.98 66.9% 0.78 0.78 0.78 0.93
Medium Density 0.00 0.65 50
Streets: Paved 0.10 0.95 90
Lawn, Clayey, >7% Slope 0.00 0.35 2
Medium Density 0.00 0.65 50
Streets: Paved 0.19 0.95 90
Lawn, Clayey, >7% Slope 0.00 0.35 2
Medium Density 0.00 0.65 50
Streets: Paved 0.06 0.95 90
Lawn, Clayey, >7% Slope 0.00 0.35 2
Medium Density 0.09 0.65 50
Streets: Paved 0.07 0.95 90
Lawn, Clayey, >7% Slope 0.00 0.35 2
Medium Density 1.30 0.65 50
Streets: Paved 0.72 0.95 90
Lawn, Clayey, >7% Slope 0.23 0.35 2
Medium Density 1.31 0.65 50
Streets: Paved 0.83 0.95 90
Lawn, Clayey, >7% Slope 0.00 0.35 2
Medium Density 1.39 0.65 50
Streets: Paved 0.64 0.95 90
Lawn, Clayey, >7% Slope 0.08 0.35 2
Medium Density 0.93 0.65 50
Streets: Paved 1.82 0.95 90
Lawn, Clayey, >7% Slope 0.63 0.35 2
Medium Density 0.56 0.65 50
Streets: Paved 0.20 0.95 90
Lawn, Clayey, >7% Slope 0.00 0.35 2
Medium Density 0.78 0.65 50
Streets: Paved 0.35 0.95 90
Lawn, Clayey, >7% Slope 0.00 0.35 2
Medium Density 0.00 0.65 50
Streets: Paved 0.34 0.95 90
Lawn, Clayey, >7% Slope 0.00 0.35 2
Medium Density 0.45 0.65 50
Streets: Paved 0.45 0.95 90
Lawn, Clayey, >7% Slope 0.00 0.35 2
Medium Density 0.83 0.65 50
Streets: Paved 0.68 0.95 90
Lawn, Clayey, >7% Slope 0.00 0.35 2
Medium Density 0.55 0.65 50
Streets: Paved 0.28 0.95 90
Lawn, Clayey, >7% Slope 0.00 0.35 2
Medium Density 0.75 0.65 50
Streets: Paved 0.39 0.95 90
Lawn, Clayey, >7% Slope 0.00 0.35 2
Medium Density 0.00 0.65 50
Streets: Paved 0.22 0.95 90
Lawn, Clayey, >7% Slope 0.00 0.35 2
Medium Density 0.05 0.65 50
Streets: Paved 0.32 0.95 90
Lawn, Clayey, >7% Slope 0.00 0.35 2
Medium Density 0.74 0.65 50
Streets: Paved 1.00 0.95 90
Lawn, Clayey, >7% Slope 0.00 0.35 2
Medium Density 0.32 0.65 50
Streets: Paved 0.07 0.95 90
Lawn, Clayey, >7% Slope 0.33 0.35 2
Medium Density 0.37 0.65 50
Streets: Paved 0.14 0.95 90
Lawn, Clayey, >7% Slope 0.00 0.35 2
Medium Density 0.66 0.65 50
Streets: Paved 0.09 0.95 90
Lawn, Clayey, >7% Slope 0.41 0.35 2
Medium Density 1.26 0.65 50
Streets: Paved 0.56 0.95 90
Lawn, Clayey, >7% Slope 0.00 0.35 2
Medium Density 0.00 0.65 50
Streets: Paved 0.09 0.95 90
Lawn, Clayey, >7% Slope 0.00 0.35 2
Medium Density 0.00 0.65 50
Streets: Paved 0.06 0.95 90
Lawn, Clayey, >7% Slope 0.00 0.35 2
Medium Density 0.10 0.65 50
Streets: Paved 0.30 0.95 90
Lawn, Clayey, >7% Slope 0.00 0.35 2
Medium Density 0.10 0.65 50
Streets: Paved 0.30 0.95 90
Lawn, Clayey, >7% Slope 0.00 0.35 2
BASIN F TOTAL 24.48 68.7% 0.81 0.81 0.81 0.93
F-25 0.40 80.0% 0.88 0.88 0.88
2.11 60.1% 0.73 0.73
0.74 0.74
1.00
0.40 80.0% 0.88 0.88 0.88 1.00
F-23 0.09
0.51 61.1%
F-24 0.06
F-26
0.95
1.00
F-11 0.34 90.0% 0.95
0.88 0.88 0.88
1.00
0.91
1.00
0.20 90.0% 0.95 0.95
0.95
0.91
1.00
0.73
0.56
0.73
0.71
0.73
0.950.95
0.56 0.56
0.73
0.73 0.73
1.00
0.85 0.85 1.000.85
0.91
D-6 1.07 71.9%
D-11 0.35 90.0%
D-8 1.60 34.7%
D-7 2.11
D-9 0.50 60.9%
76.1%
81.2%
D-1
0.95 0.95
0.81
90.0%
D-2 1.55 73.7% 0.83 0.83
D-4 0.20
D-3 1.38
0.81
0.95
60.4% 0.73 0.73
0.83
0.77
60.5%
0.73
0.95
0.81
D-5
0.82
Onsite Basin Composite Runoff Coefficients
Basin/ Sub-Basin Area (ac) Attribute
90.0%
Attribute
Area (ac)
Composite Runoff CoefficientsRunoff
Coefficient, C Percent ImperviousImpervious
0.95 0.95 1.00
D-12 0.59
0.95
0.95 1.00
0.74 0.93
F-7
D-10 1.05
0.95
D-13 0.87 0.87
1.00
0.95
0.95 1.00
F-1 0.10 90.0%
90.0% 0.95 0.95
F-3
0.92
F-2 0.19
0.54 0.54
F-5
90.0% 0.95 0.95
63.4% 0.75 0.75
0.73 0.73
90.0% 0.95 0.95
0.95
62.3% 0.740.74
0.82 0.82
31.9%
0.95
0.75 0.94
0.73 0.91
0.87 1.00
0.73
1.00
0.94
1.00
1.00
0.54 0.68
1.00
0.95
0.73 0.91
0.80
0.74 0.93
1.00
1.00
0.61
1.51 68.1% 0.79 0.79
0.95
0.95
0.95
78.9%
90.0% 0.95
0.80 0.80
0.06
2.25 57.9% 0.72
F-4 0.16 68.0% 0.79 0.79 0.79 0.98
F-6 2.14 65.6% 0.77 0.77 0.77 0.96
0.72 0.890.72
F-8 3.38 62.6% 0.76 0.76 0.76 0.94
0.73 0.7360.4%
0.71
F-22 1.82
F-17 0.37
0.98
1.00
1.00
84.2% 0.91 0.91 0.91
0.79
F-16 0.95 0.95
0.75 0.75 0.75
0.83F-14
F-13
F-9 0.76
F-10 1.13 62.5%
F-21 1.16 36.1% 0.57 0.57 0.57
F-20
F-12 0.90 70.2%
F-15 1.14 63.8%
0.22 90.0%
F-18 1.74 73.0%
F-19 0.71
MONTAVA SUBDIVISION PHASE D Preliminary Drainage Report
MONTAVA SUBDIVISION PHASE D Preliminary Drainage Report
Medium Density 0.61 0.65 50
Streets: Paved 1.96 0.95 90
Lawn, Clayey, >7% Slope 0.00 0.35 2
Medium Density 0.71 0.65 50
Streets: Paved 1.28 0.95 90
Lawn, Clayey, >7% Slope 0.00 0.35 2
Medium Density 0.00 0.65 50
Streets: Paved 0.38 0.95 90
Lawn, Clayey, >7% Slope 0.00 0.35 2
Medium Density 0.00 0.65 50
Streets: Paved 1.70 0.95 90
Lawn, Clayey, >7% Slope 0.00 0.35 2
Medium Density 0.90 0.65 50
Streets: Paved 1.23 0.95 90
Lawn, Clayey, >7% Slope 0.00 0.35 2
Medium Density 0.43 0.65 50
Streets: Paved 0.14 0.95 90
Lawn, Clayey, >7% Slope 0.00 0.35 2
Medium Density 0.74 0.65 50
Streets: Paved 0.65 0.95 90
Lawn, Clayey, >7% Slope 0.19 0.35 2
Medium Density 0.87 0.65 50
Streets: Paved 1.19 0.95 90
Lawn, Clayey, >7% Slope 0.00 0.35 2
Medium Density 0.00 0.65 50
Streets: Paved 0.14 0.95 90
Lawn, Clayey, >7% Slope 0.00 0.35 2
Medium Density 0.00 0.65 50
Streets: Paved 0.75 0.95 90
Lawn, Clayey, >7% Slope 0.00 0.35 2
BASIN G1 TOTAL 13.86 76.5% 0.85 0.85 0.85 0.99
Medium Density 0.00 0.65 50
Streets: Paved 0.56 0.95 90
Lawn, Clayey, >7% Slope 0.00 0.35 2
Medium Density 0.00 0.65 50
Streets: Paved 0.54 0.95 90
Lawn, Clayey, >7% Slope 0.00 0.35 2
BASIN C2 TOTAL 1.10 90.0% 0.95 0.95 0.95 1.00
Medium Density 0.00 0.65 50
Streets: Paved 0.85 0.95 90
Lawn, Clayey, >7% Slope 1.11 0.35 2
Medium Density 0.00 0.65 50
Streets: Paved 0.60 0.95 90
Lawn, Clayey, >7% Slope 0.79 0.35 2
GIDDINGS TOTAL 3.35 40.1% 0.61 0.61 0.61 0.76
Medium Density 0.97 0.65 50
Streets: Paved 3.15 0.95 90
Lawn, Clayey, >7% Slope 2.41 0.35 2
Medium Density 5.00 0.65 50
Streets: Paved 4.19 0.95 90
Lawn, Clayey, >7% Slope 2.00 0.35 2
Medium Density 4.00 0.65 50
Streets: Paved 3.51 0.95 90
Lawn, Clayey, >7% Slope 0.00 0.35 2
FUTURE BASINS TOTAL 25.23 58.8% 0.73 0.73 0.73 0.91
Medium Density 0.00 0.65 50
Streets: Paved 10.97 0.95 90
Lawn, Clayey, >7% Slope 7.50 0.35 2
Medium Density 0.00 0.65 50
Streets: Paved 1.48 0.95 90
Lawn, Clayey, >7% Slope 6.00 0.35 2
Medium Density 0.00 0.65 50
Streets: Paved 0.00 0.95 90
Lawn, Clayey, >7% Slope 10.12 0.35 2
POND / SCHOOL TOTAL 36.07 32.4% 0.56 0.56 0.56 0.70
Open Lands, Transition 103.82 0.20 20
Open Lands, Transition 70.35 0.20 20
OFFSITE TOTAL 174.17 20.0% 0.20 0.20 0.20 0.25
0.47
0.68 0.68 0.68
0.79
FUTURE-2 56.4% 0.71
0.590.47
0.44
0.92
1.00
0.95
0.25
73.1%
1.00
2.0% 0.35 0.35 0.35
51.6%
68.7%
0.95 0.95 1.00
40.1% 0.61 0.61 0.61 0.76
20.0%
0.71 0.71 0.89
6.53
11.19
FUTURE-1
1.00
0.82 1.00
0.91
0.74 0.74
0.82 0.82 0.82 1.00
90.0% 0.95 0.95
73.1% 0.82 0.82
60.1% 0.73 0.73
G1-1
G1-3
POND D 7.48 19.4% 0.47
1.0080.4%2.57
0.38
SCHOOL
G1-6
GIDDINGS-1 1.96
0.88 0.88 0.88
90.0% 0.95 0.95 0.95
0.73
60.8%G1-7 1.57
2.06
0.14
0.74
G1-2 1.99
G1-5
0.84 0.84
0.20
OFFSITE 2 70.35 20.0% 0.20
0.57
90.0% 0.95 0.95 0.95
75.6% 0.84
0.790.79FUTURE-3
0.85
0.99
0.25
POND 427
0.200.20
OFFSITE 1 103.82
10.12
0.20 0.20
GIDDINGS-2 1.39
G1-10 0.75 90.0% 0.95 0.95 0.95
G1-9
C2-2
18.47 54.3% 0.71 0.71
1.70
2.13
1.00
40.0% 0.61 0.61 0.61 0.76
0.54 90.0% 0.95
1.0090.0%
1.00
0.71 0.88
7.51
G1-4
C2-1 0.56 0.95 0.95 0.95
G1-8
MONTAVA SUBDIVISION PHASE D PRELIMINARY Drainage Report
Overland Flow Average Channelized Channel Channel Channelized
Length, D Overland Slope Tov Tov Tov Flow Length Slope Velocity Time (Tt)
(ft) (%) 2-year 10-year 100-year (ft) (%) (ft/s) (min) 2-year 10-year 100-year
D-1 0.95 0.95 1.00 20 2 1 1 1 844 0.5 1.4 10.0 11 11 11
D-2 0.83 0.83 1.00 60 2 3 3 1 890 0.5 1.4 10.6 14 14 12
D-3 0.73 0.73 0.91 65 2 4 4 2 345 0.5 1.4 4.1 8 8 6
D-4 0.95 0.95 1.00 20 2 1 1 1 180 0.5 1.4 2.1 5 5 5
D-5 0.95 0.95 1.00 20 2 1 1 1 170 0.5 1.4 2.0 5 5 5
D-6 0.81 0.81 1.00 20 2 2 2 1 350 0.5 1.4 4.2 6 6 5
D-7 0.73 0.73 0.91 60 2 4 4 2 740 0.5 1.4 8.8 13 13 11
D-8 0.56 0.56 0.71 60 2 6 6 5 356 0.5 1.4 4.2 10 10 9
D-9 0.73 0.73 0.91 60 2 4 4 2 155 0.5 1.4 1.8 6 6 5
D-10 0.85 0.85 1.00 60 2 3 3 1 520 0.5 1.4 6.2 9 9 7
D-11 0.95 0.95 1.00 20 2 1 1 1 375 0.5 1.4 4.5 5 5 5
D-12 0.88 0.88 1.00 20 2 1 1 1 400 0.5 1.4 4.8 6 6 6
D-13 0.87 0.87 1.00 60 2 3 3 1 320 0.5 1.4 3.8 7 7 5
F-1 0.95 0.95 1.00 15 2 1 1 1 105 0.5 1.4 1.3 5 5 5
F-2 0.95 0.95 1.00 15 2 1 1 1 250 0.5 1.4 3.0 5 5 5
F-3 0.95 0.95 1.00 15 2 1 1 1 65 0.5 1.4 0.8 5 5 5
F-4 0.79 0.79 0.98 30 2 3 3 1 65 0.5 1.4 0.8 5 5 5
F-5 0.72 0.72 0.89 60 2 4 4 2 583 0.5 1.4 6.9 11 11 9
F-6 0.77 0.77 0.96 60 2 4 4 2 775 0.5 1.4 9.2 13 13 11
F-7 0.73 0.73 0.91 60 2 4 4 2 645 0.5 1.4 7.7 12 12 10
F-8 0.76 0.76 0.94 60 2 4 4 2 835 0.5 1.4 9.9 14 14 12
F-9 0.73 0.73 0.91 60 2 4 4 2 290 0.5 1.4 3.5 7 7 5
F-10 0.74 0.74 0.93 120 2 6 6 3 140 0.5 1.4 1.7 8 8 5
F-11 0.95 0.95 1.00 20 2 1 1 1 845 0.5 1.4 10.1 11 11 11
F-12 0.80 0.80 1.00 120 2 5 5 2 200 0.5 1.4 2.4 7 7 5
F-13 0.79 0.79 0.98 60 2 4 4 1 1020 0.5 1.4 12.1 16 16 13
F-14 0.75 0.75 0.94 60 2 4 4 2 425 0.5 1.4 5.1 9 9 7
F-15 0.75 0.75 0.94 60 2 4 4 2 445 0.5 1.4 5.3 9 9 7
F-16 0.95 0.95 1.00 20 2 1 1 1 305 0.5 1.4 3.6 5 5 5
F-17 0.91 0.91 1.00 20 2 1 1 1 300 0.5 1.4 3.6 5 5 5
F-18 0.82 0.82 1.00 300 2 7 7 3 150 0.5 1.4 1.8 9 9 5
F-19 0.54 0.54 0.68 60 2 6 6 5 200 0.5 1.4 2.4 8 8 7
F-20 0.73 0.73 0.92 60 2 4 4 2 215 0.5 1.4 2.6 7 7 5
F-21 0.57 0.57 0.71 60 2 6 6 4 385 0.5 1.4 4.6 11 11 9
F-22 0.74 0.74 0.93 60 2 4 4 2 695 0.5 1.4 8.3 12 12 10
F-23 0.95 0.95 1.00 20 2 1 1 1 95 0.5 1.4 1.1 5 5 5
F-24 0.95 0.95 1.00 20 2 1 1 1 95 0.5 1.4 1.1 5 5 5
F-25 0.88 0.88 1.00 60 2 3 3 1 225 0.5 1.4 2.7 6 6 5
F-26 0.88 0.88 1.00 60 2 3 3 1 225 0.5 1.4 2.7 6 6 5
G1-1 0.88 0.88 1.00 60 2 3 3 1 815 0.5 1.4 9.7 13 13 11
G1-2 0.84 0.84 1.00 60 2 3 3 1 815 0.5 1.4 9.7 13 13 11
G1-3 0.95 0.95 1.00 20 2 1 1 1 410 0.5 1.4 4.9 6 6 6
G1-4 0.95 0.95 1.00 20 2 1 1 1 560 0.5 1.4 6.7 8 8 8
G1-5 0.82 0.82 1.00 150 2 5 5 2 50 0.5 1.4 0.6 6 6 5
G1-6 0.73 0.73 0.91 60 2 4 4 2 215 0.5 1.4 2.6 7 7 5
G1-7 0.74 0.74 0.92 60 2 4 4 2 415 0.5 1.4 4.9 9 9 7
G1-8 0.82 0.82 1.00 200 2 6 6 2 50 0.5 1.4 0.6 7 7 5
G1-9 0.95 0.95 1.00 20 2 1 1 1 95 0.5 1.4 1.1 5 5 5
G1-10 0.95 0.95 1.00 220 2 3 3 2 325 0.5 1.4 3.9 7 7 6
C2-1 0.95 0.95 1.00 20 2 1 1 1 595 0.5 1.4 7.1 8 8 8
C2-2 0.95 0.95 1.00 20 2 1 1 1 595 0.5 1.4 7.1 8 8 8
GIDDINGS-1 0.95 0.95 1.00 20 2 1 1 1 1675 0.5 1.4 19.9 21 21 21
GIDDINGS-2 0.61 0.61 0.76 20 2 3 3 2 1150 0.5 1.4 13.7 17 17 16
FUTURE-1 0.68 0.68 0.85 150 2 8 8 4 1065 0.5 1.4 12.7 21 21 17
FUTURE-2 0.71 0.71 0.89 400 2 12 12 6 1435 0.5 1.4 17.1 29 29 23
FUTURE-3 0.79 0.79 0.99 400 2 9 9 3 565 0.5 1.4 6.7 16 16 10
SCHOOL 0.71 0.71 0.88 150 2 7 7 4 1000 0.5 1.4 11.9 19 19 16
POND D 0.47 0.47 0.59 150 2 11 11 9 150 0.5 1.4 1.8 13 13 11
POND 427 0.35 0.35 0.44 20 2 5 5 4 2750 0.5 1.4 32.7 38 38 37
Basin Time of Concentration
Frequency Adj. Runoff Coefficients (C*Cf)
C2 C10 C100
Overland Travel Time Time of Concentration
Tc = Tov + Tt (min)Basin
MONTAVA SUBDIVISION PHASE D Preliminary Drainage Report
2 - year 10 - year 100 - year 2 - year 10 - year 100 - year 2 - Year 10 - Year 100 - Year 2 - Year 10 - Year 100 - Year
D-1 0.77 0.95 0.95 1.00 11 11 11 2.13 3.63 7.42 1.56 2.66 5.71
D-2 1.55 0.83 0.83 1.00 14 14 12 1.92 3.29 7.16 2.46 4.22 11.10
D-3 1.38 0.73 0.73 0.91 8 8 6 2.40 4.10 9.31 2.41 4.12 11.70
D-4 0.20 0.95 0.95 1.00 5 5 5 2.85 4.87 9.95 0.54 0.93 1.99
D-5 0.20 0.95 0.95 1.00 5 5 5 2.85 4.87 9.95 0.54 0.93 1.99
D-6 1.07 0.81 0.81 1.00 6 6 5 2.67 4.56 9.95 2.33 3.97 10.65
D-7 2.11 0.73 0.73 0.91 13 13 11 1.98 3.39 7.42 3.05 5.23 14.31
D-8 1.60 0.56 0.56 0.71 10 10 9 2.21 3.78 8.03 2.00 3.41 9.07
D-9 0.50 0.73 0.73 0.91 6 6 5 2.67 4.56 9.95 0.98 1.67 4.55
D-10 1.05 0.85 0.85 1.00 9 9 7 2.30 3.93 8.80 2.04 3.49 9.24
D-11 0.35 0.95 0.95 1.00 5 5 5 2.85 4.87 9.95 0.95 1.62 3.48
D-12 0.59 0.88 0.88 1.00 6 6 6 2.67 4.56 9.31 1.39 2.38 5.49
D-13 0.61 0.87 0.87 1.00 7 7 5 2.52 4.31 9.95 1.33 2.28 6.07
F-1 0.10 0.95 0.95 1.00 5 5 5 2.85 4.87 9.95 0.27 0.46 1.00
F-2 0.19 0.95 0.95 1.00 5 5 5 2.85 4.87 9.95 0.51 0.88 1.89
F-3 0.06 0.95 0.95 1.00 5 5 5 2.85 4.87 9.95 0.16 0.28 0.60
F-4 0.16 0.79 0.79 0.98 5 5 5 2.85 4.87 9.95 0.36 0.61 1.56
F-5 2.25 0.72 0.72 0.89 11 11 9 2.13 3.63 8.03 3.43 5.84 16.16
F-6 2.14 0.77 0.77 0.96 13 13 11 1.98 3.39 7.42 3.25 5.56 15.22
F-7 2.11 0.73 0.73 0.91 12 12 10 2.05 3.50 7.72 3.15 5.38 14.83
F-8 3.38 0.76 0.76 0.94 14 14 12 1.92 3.29 7.16 4.90 8.40 22.85
F-9 0.76 0.73 0.73 0.91 7 7 5 2.52 4.31 9.95 1.39 2.38 6.88
F-10 1.13 0.74 0.74 0.93 8 8 5 2.40 4.10 9.95 2.02 3.45 10.46
F-11 0.34 0.95 0.95 1.00 11 11 11 2.13 3.63 7.42 0.69 1.17 2.52
F-12 0.90 0.80 0.80 1.00 7 7 5 2.52 4.31 9.95 1.82 3.11 8.96
F-13 1.51 0.79 0.79 0.98 16 16 13 1.81 3.08 6.92 2.15 3.65 10.26
F-14 0.83 0.75 0.75 0.94 9 9 7 2.30 3.93 8.80 1.43 2.45 6.86
F-15 1.14 0.75 0.75 0.94 9 9 7 2.30 3.93 8.80 1.98 3.38 9.45
F-16 0.22 0.95 0.95 1.00 5 5 5 2.85 4.87 9.95 0.60 1.02 2.19
F-17 0.37 0.91 0.91 1.00 5 5 5 2.85 4.87 9.95 0.96 1.63 3.68
F-18 1.74 0.82 0.82 1.00 9 9 5 2.30 3.93 9.95 3.29 5.62 17.31
F-19 0.71 0.54 0.54 0.68 8 8 7 2.40 4.10 8.80 0.92 1.58 4.23
F-20 0.51 0.73 0.73 0.92 7 7 5 2.52 4.31 9.95 0.94 1.61 4.65
F-21 1.16 0.57 0.57 0.71 11 11 9 2.13 3.63 8.03 1.40 2.39 6.60
F-22 1.82 0.74 0.74 0.93 12 12 10 2.05 3.50 7.72 2.77 4.73 13.03
F-23 0.09 0.95 0.95 1.00 5 5 5 2.85 4.87 9.95 0.24 0.42 0.90
F-24 0.06 0.95 0.95 1.00 5 5 5 2.85 4.87 9.95 0.16 0.28 0.60
F-25 0.40 0.88 0.88 1.00 6 6 5 2.67 4.56 9.95 0.93 1.60 3.98
F-26 0.40 0.88 0.88 1.00 6 6 5 2.67 4.56 9.95 0.93 1.60 3.98
G1-1 2.57 0.88 0.88 1.00 13 13 11 1.98 3.39 7.42 4.47 7.65 19.07
G1-2 1.99 0.84 0.84 1.00 13 13 11 1.98 3.39 7.42 3.32 5.68 14.77
G1-3 0.38 0.95 0.95 1.00 6 6 6 2.67 4.56 9.31 0.96 1.65 3.54
G1-4 1.70 0.95 0.95 1.00 8 8 8 2.40 4.10 8.38 3.88 6.62 14.25
G1-5 2.13 0.82 0.82 1.00 6 6 5 2.67 4.56 9.95 4.68 8.00 21.19
G1-6 0.57 0.73 0.73 0.91 7 7 5 2.52 4.31 9.95 1.04 1.78 5.15
G1-7 1.57 0.74 0.74 0.92 9 9 7 2.30 3.93 8.80 2.66 4.55 12.74
G1-8 2.06 0.82 0.82 1.00 7 7 5 2.52 4.31 9.95 4.27 7.31 20.50
G1-9 0.14 0.95 0.95 1.00 5 5 5 2.85 4.87 9.95 0.38 0.65 1.39
G1-10 0.75 0.95 0.95 1.00 7 7 6 2.52 4.31 9.31 1.80 3.07 6.98
C2-1 0.56 0.95 0.95 1.00 8 8 8 2.40 4.10 8.38 1.28 2.18 4.69
C2-2 0.54 0.95 0.95 1.00 8 8 8 2.40 4.10 8.38 1.23 2.10 4.53
GIDDINGS-1 1.96 0.95 0.95 1.00 21 21 21 1.56 2.67 5.46 2.90 4.97 10.70
GIDDINGS-2 1.39 0.61 0.61 0.76 17 17 16 1.75 2.99 6.30 1.48 2.53 6.67
FUTURE-1 6.53 0.68 0.68 0.85 21 21 17 1.56 2.67 6.10 6.97 11.93 34.06
FUTURE-2 11.19 0.71 0.71 0.89 29 29 23 1.32 2.25 5.20 10.47 17.84 51.55
FUTURE-3 7.51 0.79 0.79 0.99 16 16 10 1.81 3.08 7.72 10.74 18.28 57.27
SCHOOL 18.47 0.71 0.71 0.88 19 19 16 1.65 2.82 6.30 21.53 36.79 102.74
POND D 7.48 0.47 0.47 0.59 13 13 11 1.98 3.39 7.42 6.94 11.89 32.52
POND 427 10.12 0.35 0.35 0.44 38 38 37 1.11 1.89 3.93 3.93 6.69 17.40
Basin Peak Discharge
Rainfall Intensity (in/hr) Peak Discharge (cfs)Basin Basin Area
(ac)
Frequency Adj. Runoff Coefficients Time of Concentration, Tc (min)
MONTAVA SUBDIVISION PHASE D Preliminary Drainage Report
PROPOSED
IMPERVIOUSNESS
EXISTING
IMPERVIOUSNESS
D-1 90% 30%
D-2 74% 30%
D-3 60% 30%
D-4 90% 30%
D-5 90% 30%
D-6 72% 30%
D-7 61% 30%
D-8 35% 30%
D-9 61% 30%
D-10 76% 30%
D-11 90% 30%
D-12 81% 30%
D-13 79%30%
F-1 90% 30%
F-2 90% 30%
F-3 90% 30%
F-4 68% 30%
F-5 58% 30%
F-6 66% 30%
F-7 60% 30%
F-8 63% 30%
F-9 60% 30%
F-10 63% 30%
F-11 90% 30%
F-12 70% 30%
F-13 68% 30%
F-14 63% 30%
F-15 64% 30%
F-16 90% 30%
F-17 84% 30%
F-18 73% 30%
F-19 32% 30%
F-20 61% 30%
F-21 36% 30%
F-22 62% 30%
F-23 90% 30%
F-24 90% 30%
F-25 80% 30%
F-26 80%30%
G1-1 80% 30%
G1-2 76% 30%
G1-3 90% 30%
G1-4 90% 30%
G1-5 73% 30%
G1-6 60% 30%
G1-7 61% 30%
G1-8 73% 30%
G1-9 90% 30%
G1-10 90%30%
C2-1 90% 30%
C2-2 90%30%
GIDDINGS-1 40% 40%
GIDDINGS-2 40%40%
FUTURE-1 52% 30%
FUTURE-2 56% 30%
FUTURE-3 69%30%
SCHOOL 54%30%
POND D 19%30%
POND 427 2%30%
Appendix B
LOW IMPACT DEVELOPMENT
(LID) CALCULATIONS
Sheet 1 of 2
Designer:
Company:
Date:
Project:
Location:
1. Basin Storage Volume
A) Effective Imperviousness of Tributary Area, Ia Ia =57.8 %
(100% if all paved and roofed areas upstream of rain garden)
B) Tributary Area's Imperviousness Ratio (i = Ia/100)i = 0.578
C) Water Quality Capture Volume (WQCV) for a 12-hour Drain Time WQCV = 0.18 watershed inches
(WQCV= 0.8 * (0.91* i3 - 1.19 * i2 + 0.78 * i)
D) Contributing Watershed Area (including rain garden area) Area = 307,687 sq ft
E) Water Quality Capture Volume (WQCV) Design Volume VWQCV =cu ft
Vol = (WQCV / 12) * Area
F) For Watersheds Outside of the Denver Region, Depth of d6 =0.60 in
Average Runoff Producing Storm
G) For Watersheds Outside of the Denver Region, VWQCV OTHER =6,557 cu ft
Water Quality Capture Volume (WQCV) Design Volume
H) User Input of Water Quality Capture Volume (WQCV) Design Volume VWQCV USER =cu ft
(Only if a different WQCV Design Volume is desired)
2. Basin Geometry
A) WQCV Depth (12-inch maximum)DWQCV =10 in
B) Rain Garden Side Slopes (Z = 4 min., horiz. dist per unit vertical) Z = 4.00 ft / ft
(Use "0" if rain garden has vertical walls)
C) Mimimum Flat Surface Area AMin =3559 sq ft
D) Actual Flat Surface Area AActual =6931 sq ft
E) Area at Design Depth (Top Surface Area)ATop =9068 sq ft
F) Rain Garden Total Volume VT=6,666 cu ft
(VT= ((ATop + AActual) / 2) * Depth)
3. Growing Media
4. Underdrain System
A) Are underdrains provided?
B) Underdrain system orifice diameter for 12 hour drain time
i) Distance From Lowest Elevation of the Storage y =ft
Volume to the Center of the Orifice
ii) Volume to Drain in 12 Hours Vol12 =cu ft
iii) Orifice Diameter, 3/8" Minimum DO = in
Design Procedure Form: Rain Garden (RG)
BAMG
TST INC.
April 30, 2024
MONTAVA PHASE D
FORT COLLINS CO
UD-BMP (Version 3.07, March 2018)
Choose One
Choose One
18" Rain Garden Growing Media
Other (Explain):
YES
NO
UD-BMP_BASIN D LID 1.xlsm, RG 4/30/2024, 11:08 AM
LID-2
Sheet 1 of 2
Designer:
Company:
Date:
Project:
Location:
1. Basin Storage Volume
A) Effective Imperviousness of Tributary Area, Ia Ia =63.5 %
(100% if all paved and roofed areas upstream of rain garden)
B) Tributary Area's Imperviousness Ratio (i = Ia/100)i = 0.635
C) Water Quality Capture Volume (WQCV) for a 12-hour Drain Time WQCV = 0.20 watershed inches
(WQCV= 0.8 * (0.91* i3 - 1.19 * i2 + 0.78 * i)
D) Contributing Watershed Area (including rain garden area) Area = 254,289 sq ft
E) Water Quality Capture Volume (WQCV) Design Volume VWQCV =cu ft
Vol = (WQCV / 12) * Area
F) For Watersheds Outside of the Denver Region, Depth of d6 =0.60 in
Average Runoff Producing Storm
G) For Watersheds Outside of the Denver Region, VWQCV OTHER =5,881 cu ft
Water Quality Capture Volume (WQCV) Design Volume
H) User Input of Water Quality Capture Volume (WQCV) Design Volume VWQCV USER =cu ft
(Only if a different WQCV Design Volume is desired)
2. Basin Geometry
A) WQCV Depth (12-inch maximum)DWQCV =10 in
B) Rain Garden Side Slopes (Z = 4 min., horiz. dist per unit vertical) Z = 4.00 ft / ft
(Use "0" if rain garden has vertical walls)
C) Mimimum Flat Surface Area AMin =3232 sq ft
D) Actual Flat Surface Area AActual =6134 sq ft
E) Area at Design Depth (Top Surface Area)ATop =8867 sq ft
F) Rain Garden Total Volume VT=6,250 cu ft
(VT= ((ATop + AActual) / 2) * Depth)
3. Growing Media
4. Underdrain System
A) Are underdrains provided?
B) Underdrain system orifice diameter for 12 hour drain time
i) Distance From Lowest Elevation of the Storage y =ft
Volume to the Center of the Orifice
ii) Volume to Drain in 12 Hours Vol12 =cu ft
iii) Orifice Diameter, 3/8" Minimum DO = in
Design Procedure Form: Rain Garden (RG)
BAMG
TST INC.
April 30, 2024
MONTAVA SUBDIVISION PHASE D
FORT COLLINS, CO
UD-BMP (Version 3.07, March 2018)
Choose One
Choose One
18" Rain Garden Growing Media
Other (Explain):
YES
NO
UD-BMP_BASIN F LID 1.xlsm, RG 4/30/2024, 11:37 AM
LID-3
Sheet 1 of 2
Designer:
Company:
Date:
Project:
Location:
1. Basin Storage Volume
A) Effective Imperviousness of Tributary Area, Ia Ia =53.4 %
(100% if all paved and roofed areas upstream of rain garden)
B) Tributary Area's Imperviousness Ratio (i = Ia/100)i = 0.534
C) Water Quality Capture Volume (WQCV) for a 12-hour Drain Time WQCV = 0.17 watershed inches
(WQCV= 0.8 * (0.91* i3 - 1.19 * i2 + 0.78 * i)
D) Contributing Watershed Area (including rain garden area) Area = 408,157 sq ft
E) Water Quality Capture Volume (WQCV) Design Volume VWQCV =cu ft
Vol = (WQCV / 12) * Area
F) For Watersheds Outside of the Denver Region, Depth of d6 =0.60 in
Average Runoff Producing Storm
G) For Watersheds Outside of the Denver Region, VWQCV OTHER =8,192 cu ft
Water Quality Capture Volume (WQCV) Design Volume
H) User Input of Water Quality Capture Volume (WQCV) Design Volume VWQCV USER =cu ft
(Only if a different WQCV Design Volume is desired)
2. Basin Geometry
A) WQCV Depth (12-inch maximum)DWQCV =10 in
B) Rain Garden Side Slopes (Z = 4 min., horiz. dist per unit vertical) Z = 4.00 ft / ft
(Use "0" if rain garden has vertical walls)
C) Mimimum Flat Surface Area AMin =4359 sq ft
D) Actual Flat Surface Area AActual =7577 sq ft
E) Area at Design Depth (Top Surface Area)ATop =13668 sq ft
F) Rain Garden Total Volume VT=8,852 cu ft
(VT= ((ATop + AActual) / 2) * Depth)
3. Growing Media
4. Underdrain System
A) Are underdrains provided?
B) Underdrain system orifice diameter for 12 hour drain time
i) Distance From Lowest Elevation of the Storage y =ft
Volume to the Center of the Orifice
ii) Volume to Drain in 12 Hours Vol12 =cu ft
iii) Orifice Diameter, 3/8" Minimum DO = in
Design Procedure Form: Rain Garden (RG)
BAMG
TST INC.
April 30, 2024
MONTAVA SUBDIVISION PHASE D
FORT COLLINS, CO
UD-BMP (Version 3.07, March 2018)
Choose One
Choose One
18" Rain Garden Growing Media
Other (Explain):
YES
NO
UD-BMP_BASIN F LID 3.xlsm, RG 4/30/2024, 11:43 AM
LID-4
Sheet 1 of 2
Designer:
Company:
Date:
Project:
Location:
1. Basin Storage Volume
A) Effective Imperviousness of Tributary Area, Ia Ia =57.2 %
(100% if all paved and roofed areas upstream of rain garden)
B) Tributary Area's Imperviousness Ratio (i = Ia/100)i = 0.572
C) Water Quality Capture Volume (WQCV) for a 12-hour Drain Time WQCV = 0.18 watershed inches
(WQCV= 0.8 * (0.91* i3 - 1.19 * i2 + 0.78 * i)
D) Contributing Watershed Area (including rain garden area) Area = 304,235 sq ft
E) Water Quality Capture Volume (WQCV) Design Volume VWQCV =cu ft
Vol = (WQCV / 12) * Area
F) For Watersheds Outside of the Denver Region, Depth of d6 =0.60 in
Average Runoff Producing Storm
G) For Watersheds Outside of the Denver Region, VWQCV OTHER =6,424 cu ft
Water Quality Capture Volume (WQCV) Design Volume
H) User Input of Water Quality Capture Volume (WQCV) Design Volume VWQCV USER =cu ft
(Only if a different WQCV Design Volume is desired)
2. Basin Geometry
A) WQCV Depth (12-inch maximum)DWQCV =10 in
B) Rain Garden Side Slopes (Z = 4 min., horiz. dist per unit vertical) Z = 4.00 ft / ft
(Use "0" if rain garden has vertical walls)
C) Mimimum Flat Surface Area AMin =3478 sq ft
D) Actual Flat Surface Area AActual =6697 sq ft
E) Area at Design Depth (Top Surface Area)ATop =9457 sq ft
F) Rain Garden Total Volume VT=6,731 cu ft
(VT= ((ATop + AActual) / 2) * Depth)
3. Growing Media
4. Underdrain System
A) Are underdrains provided?
B) Underdrain system orifice diameter for 12 hour drain time
i) Distance From Lowest Elevation of the Storage y =ft
Volume to the Center of the Orifice
ii) Volume to Drain in 12 Hours Vol12 =cu ft
iii) Orifice Diameter, 3/8" Minimum DO = in
Design Procedure Form: Rain Garden (RG)
BAMG
TST INC
April 30, 2024
MONTAVA PHASE D
FORT COLLINS, CO
UD-BMP (Version 3.07, March 2018)
Choose One
Choose One
18" Rain Garden Growing Media
Other (Explain):
YES
NO
UD-BMP_BASIN F LID 2.xlsm, RG 4/30/2024, 11:10 AM
LID-5
Sheet 1 of 2
Designer:
Company:
Date:
Project:
Location:
1. Basin Storage Volume
A) Effective Imperviousness of Tributary Area, Ia Ia =46.0 %
(100% if all paved and roofed areas upstream of rain garden)
B) Tributary Area's Imperviousness Ratio (i = Ia/100)i = 0.460
C) Water Quality Capture Volume (WQCV) for a 12-hour Drain Time WQCV = 0.16 watershed inches
(WQCV= 0.8 * (0.91* i3 - 1.19 * i2 + 0.78 * i)
D) Contributing Watershed Area (including rain garden area) Area = 202,990 sq ft
E) Water Quality Capture Volume (WQCV) Design Volume VWQCV =cu ft
Vol = (WQCV / 12) * Area
F) For Watersheds Outside of the Denver Region, Depth of d6 =0.60 in
Average Runoff Producing Storm
G) For Watersheds Outside of the Denver Region, VWQCV OTHER =3,693 cu ft
Water Quality Capture Volume (WQCV) Design Volume
H) User Input of Water Quality Capture Volume (WQCV) Design Volume VWQCV USER =cu ft
(Only if a different WQCV Design Volume is desired)
2. Basin Geometry
A) WQCV Depth (12-inch maximum)DWQCV =10 in
B) Rain Garden Side Slopes (Z = 4 min., horiz. dist per unit vertical) Z = 4.00 ft / ft
(Use "0" if rain garden has vertical walls)
C) Mimimum Flat Surface Area AMin =1868 sq ft
D) Actual Flat Surface Area AActual =4768 sq ft
E) Area at Design Depth (Top Surface Area)ATop =7515 sq ft
F) Rain Garden Total Volume VT=5,118 cu ft
(VT= ((ATop + AActual) / 2) * Depth)
3. Growing Media
4. Underdrain System
A) Are underdrains provided?
B) Underdrain system orifice diameter for 12 hour drain time
i) Distance From Lowest Elevation of the Storage y =ft
Volume to the Center of the Orifice
ii) Volume to Drain in 12 Hours Vol12 =cu ft
iii) Orifice Diameter, 3/8" Minimum DO = in
Design Procedure Form: Rain Garden (RG)
BAMG
TST INC.
April 30, 2024
MONTAVA SUBDIVISION PHASE D
FORT COLLINS, CO
UD-BMP (Version 3.07, March 2018)
Choose One
Choose One
18" Rain Garden Growing Media
Other (Explain):
YES
NO
UD-BMP_BASIN F LID 4.xlsm, RG 4/30/2024, 11:46 AM
LID-6
Appendix C
FEMA FLOOD INSURANCE
RATE MAP
National Flood Hazard Layer FIRMette
0 500 1,000 1,500 2,000250
Feet
Ü
SEE FIS REPORT FOR DETAILED LEGEND AND INDEX MAP FOR FIRM PANEL LAYOUT
SPECIAL FLOOD
HAZARD AREAS
Without Base Flood Elevation (BFE)
Zone A, V, A99
With BFE or DepthZone AE, AO, AH, VE, AR
Regulatory Floodway
0.2% Annual Chance Flood Hazard, Areas
of 1% annual chance flood with average
depth less than one foot or with drainage
areas of less than one square mileZone X
Future Conditions 1% Annual
Chance Flood HazardZone X
Area with Reduced Flood Risk due to
Levee. See Notes.Zone X
Area with Flood Risk due to LeveeZone D
NO SCREEN Area of Minimal Flood Hazard Zone X
Area of Undetermined Flood HazardZone D
Channel, Culvert, or Storm Sewer
Levee, Dike, or Floodwall
Cross Sections with 1% Annual Chance
17.5 Water Surface Elevation
Coastal Transect
Coastal Transect Baseline
Profile Baseline
Hydrographic Feature
Base Flood Elevation Line (BFE)
Effective LOMRs
Limit of Study
Jurisdiction 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 the
authoritative NFHL web services provided by FEMA. This map
was exported on 4/4/2024 at 12:17 PM and does not
reflect changes or amendments subsequent to this date and
time. The NFHL and effective information may change or
become superseded by new data over time.
This map image is void if the one or more of the following map
elements 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 for
unmapped and unmodernized areas cannot be used for
regulatory purposes.
Legend
OTHER AREAS OF
FLOOD HAZARD
OTHER AREAS
GENERAL
STRUCTURES
OTHER
FEATURES
MAP PANELS
8
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.
1:6,000
105°1'42"W 40°37'4"N
105°1'5"W 40°36'37"N
Basemap Imagery Source: USGS National Map 2023
Appendix D
USDA HYDROLOGIC SOIL
GROUP MAP
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
Larimer County
Area, ColoradoNatural
Resources
Conservation
Service
April 4, 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................................................................................................................9
Legend................................................................................................................10
Map Unit Legend................................................................................................11
Map Unit Descriptions.........................................................................................11
Larimer County Area, Colorado......................................................................13
5—Aquepts, loamy......................................................................................13
35—Fort Collins loam, 0 to 3 percent slopes..............................................14
36—Fort Collins loam, 3 to 5 percent slopes..............................................15
95—Satanta loam, 1 to 3 percent slopes....................................................17
98—Satanta Variant clay loam, 0 to 3 percent slopes.................................18
Soil Information for All Uses...............................................................................20
Soil Properties and Qualities..............................................................................20
Soil Qualities and Features.............................................................................20
Hydrologic Soil Group.................................................................................20
References............................................................................................................25
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
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497600 497700 497800 497900 498000 498100 498200 498300 498400
497600 497700 497800 497900 498000 498100 498200 498300 498400
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Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 13N WGS84
0 250 500 1000 1500
Feet
0 50 100 200 300
Meters
Map Scale: 1:5,540 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: Larimer County Area, Colorado
Survey Area Data: Version 18, Aug 24, 2023
Soil map units are labeled (as space allows) for map scales
1:50,000 or larger.
Date(s) aerial images were photographed: Jul 2, 2021—Aug 25,
2021
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
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Map Unit Legend
Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI
5 Aquepts, loamy 0.5 0.5%
35 Fort Collins loam, 0 to 3 percent
slopes
33.0 33.5%
36 Fort Collins loam, 3 to 5 percent
slopes
2.3 2.4%
95 Satanta loam, 1 to 3 percent
slopes
3.0 3.0%
98 Satanta Variant clay loam, 0 to
3 percent slopes
59.9 60.7%
Totals for Area of Interest 98.7 100.0%
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.
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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.
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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12
Larimer County Area, Colorado
5—Aquepts, loamy
Map Unit Setting
National map unit symbol: jpws
Elevation: 4,500 to 6,700 feet
Mean annual precipitation: 12 to 18 inches
Mean annual air temperature: 39 to 50 degrees F
Frost-free period: 80 to 140 days
Farmland classification: Not prime farmland
Map Unit Composition
Aquepts and similar soils:80 percent
Minor components:20 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
Description of Aquepts
Setting
Landform:Depressions, draws, stream terraces
Landform position (three-dimensional):Base slope, tread, dip
Down-slope shape:Linear
Across-slope shape:Linear
Parent material:Loamy alluvium
Typical profile
H1 - 0 to 60 inches: variable
Properties and qualities
Slope:0 to 3 percent
Depth to restrictive feature:More than 80 inches
Drainage class:Very poorly drained
Runoff class: Negligible
Capacity of the most limiting layer to transmit water (Ksat):Moderately high to very
high (0.60 to 99.90 in/hr)
Depth to water table:About 6 to 18 inches
Frequency of flooding:Rare
Frequency of ponding:None
Interpretive groups
Land capability classification (irrigated): 5w
Land capability classification (nonirrigated): 3w
Hydrologic Soil Group: A/D
Ecological site: R067BY038CO - Wet Meadow
Hydric soil rating: Yes
Minor Components
Nunn
Percent of map unit:5 percent
Ecological site:R067BY002CO - Loamy Plains
Hydric soil rating: No
Kim
Percent of map unit:5 percent
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Ecological site:R067BY002CO - Loamy Plains
Hydric soil rating: No
Stoneham
Percent of map unit:5 percent
Ecological site:R067BY002CO - Loamy Plains
Hydric soil rating: No
Fort collins
Percent of map unit:5 percent
Ecological site:R067BY002CO - Loamy Plains
Hydric soil rating: No
35—Fort Collins loam, 0 to 3 percent slopes
Map Unit Setting
National map unit symbol: 2tlnc
Elevation: 4,020 to 6,730 feet
Mean annual precipitation: 14 to 16 inches
Mean annual air temperature: 46 to 48 degrees F
Frost-free period: 135 to 160 days
Farmland classification: Prime farmland if irrigated
Map Unit Composition
Fort collins and similar soils:85 percent
Minor components:15 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
Description of Fort Collins
Setting
Landform:Interfluves, stream terraces
Landform position (three-dimensional):Interfluve, tread
Down-slope shape:Linear
Across-slope shape:Linear
Parent material:Pleistocene or older alluvium and/or eolian deposits
Typical profile
Ap - 0 to 4 inches: loam
Bt1 - 4 to 9 inches: clay loam
Bt2 - 9 to 16 inches: clay loam
Bk1 - 16 to 29 inches: loam
Bk2 - 29 to 80 inches: loam
Properties and qualities
Slope:0 to 3 percent
Depth to restrictive feature:More than 80 inches
Drainage class:Well drained
Runoff class: Low
Capacity of the most limiting layer to transmit water (Ksat):Moderately high to high
(0.20 to 2.00 in/hr)
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Depth to water table:More than 80 inches
Frequency of flooding:None
Frequency of ponding:None
Calcium carbonate, maximum content:12 percent
Maximum salinity:Nonsaline to very slightly saline (0.1 to 2.0 mmhos/cm)
Available water supply, 0 to 60 inches: High (about 9.1 inches)
Interpretive groups
Land capability classification (irrigated): 3e
Land capability classification (nonirrigated): 3e
Hydrologic Soil Group: C
Ecological site: R067BY002CO - Loamy Plains
Hydric soil rating: No
Minor Components
Nunn
Percent of map unit:10 percent
Landform:Stream terraces
Landform position (three-dimensional):Tread
Down-slope shape:Linear
Across-slope shape:Linear
Ecological site:R067BY002CO - Loamy Plains
Hydric soil rating: No
Vona
Percent of map unit:5 percent
Landform:Interfluves
Landform position (three-dimensional):Interfluve, side slope
Down-slope shape:Linear
Across-slope shape:Linear
Ecological site:R067BY024CO - Sandy Plains
Hydric soil rating: No
36—Fort Collins loam, 3 to 5 percent slopes
Map Unit Setting
National map unit symbol: 2yqpg
Elevation: 4,800 to 5,900 feet
Mean annual precipitation: 13 to 15 inches
Mean annual air temperature: 48 to 50 degrees F
Frost-free period: 135 to 150 days
Farmland classification: Prime farmland if irrigated
Map Unit Composition
Fort collins and similar soils:80 percent
Minor components:20 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
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Description of Fort Collins
Setting
Landform:Alluvial fans, terraces
Landform position (three-dimensional):Tread
Down-slope shape:Linear, convex
Across-slope shape:Linear
Parent material:Pleistocene or older alluvium and/or eolian deposits
Typical profile
Ap - 0 to 5 inches: loam
Bt1 - 5 to 8 inches: clay loam
Bt2 - 8 to 18 inches: clay loam
Bk1 - 18 to 24 inches: loam
Bk2 - 24 to 80 inches: loam
Properties and qualities
Slope:3 to 5 percent
Depth to restrictive feature:More than 80 inches
Drainage class:Well drained
Runoff class: Low
Capacity of the most limiting layer to transmit water (Ksat):Moderately high to high
(0.20 to 2.00 in/hr)
Depth to water table:More than 80 inches
Frequency of flooding:None
Frequency of ponding:None
Calcium carbonate, maximum content:12 percent
Maximum salinity:Nonsaline to very slightly saline (0.1 to 2.0 mmhos/cm)
Available water supply, 0 to 60 inches: High (about 9.1 inches)
Interpretive groups
Land capability classification (irrigated): 4e
Land capability classification (nonirrigated): 4e
Hydrologic Soil Group: C
Ecological site: R067BY002CO - Loamy Plains
Hydric soil rating: No
Minor Components
Table mountain
Percent of map unit:15 percent
Landform:Alluvial fans, stream terraces
Landform position (three-dimensional):Tread
Down-slope shape:Linear
Across-slope shape:Linear
Ecological site:R067BY036CO - Overflow
Hydric soil rating: No
Larim
Percent of map unit:5 percent
Landform:Alluvial fans
Down-slope shape:Linear
Across-slope shape:Linear
Ecological site:R067BY063CO - Gravel Breaks
Hydric soil rating: No
Custom Soil Resource Report
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95—Satanta loam, 1 to 3 percent slopes
Map Unit Setting
National map unit symbol: 2w5f3
Elevation: 3,650 to 5,350 feet
Mean annual precipitation: 12 to 18 inches
Mean annual air temperature: 46 to 54 degrees F
Frost-free period: 115 to 155 days
Farmland classification: Prime farmland if irrigated
Map Unit Composition
Satanta and similar soils:90 percent
Minor components:10 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
Description of Satanta
Setting
Landform:Paleoterraces
Landform position (two-dimensional):Backslope
Landform position (three-dimensional):Head slope
Down-slope shape:Linear
Across-slope shape:Linear
Parent material:Eolian sands
Typical profile
Ap - 0 to 9 inches: loam
Bt - 9 to 18 inches: clay loam
C - 18 to 79 inches: loam
Properties and qualities
Slope:1 to 3 percent
Depth to restrictive feature:More than 80 inches
Drainage class:Well drained
Runoff class: Low
Capacity of the most limiting layer to transmit water (Ksat):Moderately high (0.20
to 0.60 in/hr)
Depth to water table:More than 80 inches
Frequency of flooding:None
Frequency of ponding:None
Calcium carbonate, maximum content:10 percent
Maximum salinity:Nonsaline to very slightly saline (0.0 to 2.0 mmhos/cm)
Available water supply, 0 to 60 inches: Very high (about 12.2 inches)
Interpretive groups
Land capability classification (irrigated): 3e
Land capability classification (nonirrigated): 4c
Hydrologic Soil Group: C
Ecological site: R067BY002CO - Loamy Plains
Hydric soil rating: No
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Minor Components
Nunn
Percent of map unit:5 percent
Landform:Terraces
Landform position (three-dimensional):Tread
Down-slope shape:Linear
Across-slope shape:Linear
Ecological site:R067BY002CO - Loamy Plains
Hydric soil rating: No
Fort collins
Percent of map unit:5 percent
Landform:Alluvial fans
Landform position (two-dimensional):Backslope
Landform position (three-dimensional):Head slope
Down-slope shape:Linear
Across-slope shape:Linear
Ecological site:R067BY002CO - Loamy Plains
Hydric soil rating: No
98—Satanta Variant clay loam, 0 to 3 percent slopes
Map Unit Setting
National map unit symbol: jpyh
Elevation: 4,800 to 5,600 feet
Mean annual precipitation: 13 to 15 inches
Mean annual air temperature: 48 to 50 degrees F
Frost-free period: 135 to 150 days
Farmland classification: Prime farmland if irrigated
Map Unit Composition
Satanta variant and similar soils:90 percent
Minor components:10 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
Description of Satanta Variant
Setting
Landform:Terraces
Landform position (three-dimensional):Tread
Down-slope shape:Linear
Across-slope shape:Linear
Parent material:Alluvium
Typical profile
H1 - 0 to 9 inches: clay loam
H2 - 9 to 22 inches: clay loam
H3 - 22 to 60 inches: loam
Custom Soil Resource Report
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Properties and qualities
Slope:0 to 3 percent
Depth to restrictive feature:More than 80 inches
Drainage class:Somewhat poorly drained
Runoff class: High
Capacity of the most limiting layer to transmit water (Ksat):Moderately low to
moderately high (0.06 to 0.20 in/hr)
Depth to water table:About 24 to 48 inches
Frequency of flooding:Occasional
Frequency of ponding:None
Calcium carbonate, maximum content:15 percent
Gypsum, maximum content:10 percent
Maximum salinity:Very slightly saline to slightly saline (2.0 to 4.0 mmhos/cm)
Available water supply, 0 to 60 inches: Moderate (about 8.7 inches)
Interpretive groups
Land capability classification (irrigated): 2e
Land capability classification (nonirrigated): 4e
Hydrologic Soil Group: D
Ecological site: R067BY036CO - Overflow
Hydric soil rating: No
Minor Components
Nunn
Percent of map unit:5 percent
Ecological site:R067BY002CO - Loamy Plains
Hydric soil rating: No
Caruso
Percent of map unit:3 percent
Ecological site:R067BY036CO - Overflow
Hydric soil rating: No
Loveland
Percent of map unit:2 percent
Ecological site:R067BY036CO - Overflow
Hydric soil rating: No
Custom Soil Resource Report
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Soil Information for All Uses
Soil Properties and Qualities
The Soil Properties and Qualities section includes various soil properties and
qualities displayed as thematic maps with a summary table for the soil map units in
the selected area of interest. A single value or rating for each map unit is generated
by aggregating the interpretive ratings of individual map unit components. This
aggregation process is defined for each property or quality.
Soil Qualities and Features
Soil qualities are behavior and performance attributes that are not directly
measured, but are inferred from observations of dynamic conditions and from soil
properties. Example soil qualities include natural drainage, and frost action. Soil
features are attributes that are not directly part of the soil. Example soil features
include slope and depth to restrictive layer. These features can greatly impact the
use and management of the soil.
Hydrologic Soil Group
Hydrologic soil groups are based on estimates of runoff potential. Soils are
assigned to one of four groups according to the rate of water infiltration when the
soils are not protected by vegetation, are thoroughly wet, and receive precipitation
from long-duration storms.
The soils in the United States are assigned to four groups (A, B, C, and D) and
three dual classes (A/D, B/D, and C/D). The groups are defined as follows:
Group A. Soils having a high infiltration rate (low runoff potential) when thoroughly
wet. These consist mainly of deep, well drained to excessively drained sands or
gravelly sands. These soils have a high rate of water transmission.
Group B. Soils having a moderate infiltration rate when thoroughly wet. These
consist chiefly of moderately deep or deep, moderately well drained or well drained
soils that have moderately fine texture to moderately coarse texture. These soils
have a moderate rate of water transmission.
20
Group C. Soils having a slow infiltration rate when thoroughly wet. These consist
chiefly of soils having a layer that impedes the downward movement of water or
soils of moderately fine texture or fine texture. These soils have a slow rate of water
transmission.
Group D. Soils having a very slow infiltration rate (high runoff potential) when
thoroughly wet. These consist chiefly of clays that have a high shrink-swell
potential, soils that have a high water table, soils that have a claypan or clay layer at
or near the surface, and soils that are shallow over nearly impervious material.
These soils have a very slow rate of water transmission.
If a soil is assigned to a dual hydrologic group (A/D, B/D, or C/D), the first letter is
for drained areas and the second is for undrained areas. Only the soils that in their
natural condition are in group D are assigned to dual classes.
Custom Soil Resource Report
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22
Custom Soil Resource Report
Map—Hydrologic Soil Group
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W
N
Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 13N WGS84
0 250 500 1000 1500
Feet
0 50 100 200 300
Meters
Map Scale: 1:5,540 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 Rating Polygons
A
A/D
B
B/D
C
C/D
D
Not rated or not available
Soil Rating Lines
A
A/D
B
B/D
C
C/D
D
Not rated or not available
Soil Rating Points
A
A/D
B
B/D
C
C/D
D
Not rated or not available
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: Larimer County Area, Colorado
Survey Area Data: Version 18, Aug 24, 2023
Soil map units are labeled (as space allows) for map scales
1:50,000 or larger.
Date(s) aerial images were photographed: Jul 2, 2021—Aug 25,
2021
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
23
Table—Hydrologic Soil Group
Map unit symbol Map unit name Rating Acres in AOI Percent of AOI
5 Aquepts, loamy A/D 0.5 0.5%
35 Fort Collins loam, 0 to 3
percent slopes
C 33.0 33.5%
36 Fort Collins loam, 3 to 5
percent slopes
C 2.3 2.4%
95 Satanta loam, 1 to 3
percent slopes
C 3.0 3.0%
98 Satanta Variant clay
loam, 0 to 3 percent
slopes
D 59.9 60.7%
Totals for Area of Interest 98.7 100.0%
Rating Options—Hydrologic Soil Group
Aggregation Method: Dominant Condition
Component Percent Cutoff: None Specified
Tie-break Rule: Higher
Custom Soil Resource Report
24
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
25
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
26
Appendix E
DRAINAGE PLANS
Appendix F
DETENTION DESIGN
Project:
Basin ID:
Depth Increment = 1.00 ft
Watershed Information 4987 Top of Micropool -- 0.00 -- -- -- 173 0.004
Selected BMP Type =EDB 4988 -- 1.00 -- -- -- 8,162 0.187 4,168 0.096
Watershed Area = 68.02 acres 4989 -- 2.00 -- -- -- 35,772 0.821 26,134 0.600
Watershed Length = 3,367 ft 4990 -- 3.00 -- -- -- 75,228 1.727 81,634 1.874
Watershed Length to Centroid = 2,366 ft 4991 -- 4.00 -- -- -- 107,043 2.457 172,770 3.966
Watershed Slope = 0.050 ft/ft 4992 -- 5.00 -- -- -- 133,704 3.069 293,143 6.730
Watershed Imperviousness = 65.60% percent 4993 -- 6.00 -- -- -- 151,585 3.480 435,788 10.004
Percentage Hydrologic Soil Group A = 0.0% percent 4994 -- 7.00 -- -- -- 160,821 3.692 591,991 13.590
Percentage Hydrologic Soil Group B = 0.0% percent 4995 -- 8.00 -- -- -- 167,206 3.839 756,005 17.355
Percentage Hydrologic Soil Groups C/D = 100.0% percent -- -- -- --
Target WQCV Drain Time = 40.0 hours -- -- -- --
Location for 1-hr Rainfall Depths = Denver - Capitol Building -- -- -- --
-- -- -- --
-- -- -- --
Optional User Overrides -- -- -- --
Water Quality Capture Volume (WQCV) = 1.454 acre-feet acre-feet -- -- -- --
Excess Urban Runoff Volume (EURV) = 4.314 acre-feet acre-feet -- -- -- --
2-yr Runoff Volume (P1 = 0.83 in.) = 2.851 acre-feet inches -- -- -- --
5-yr Runoff Volume (P1 = 1.09 in.) = 4.096 acre-feet inches -- -- -- --
10-yr Runoff Volume (P1 = 1.33 in.) = 5.388 acre-feet inches -- -- -- --
25-yr Runoff Volume (P1 = 1.69 in.) = 7.652 acre-feet inches -- -- -- --
50-yr Runoff Volume (P1 = 1.99 in.) = 9.415 acre-feet inches -- -- -- --
100-yr Runoff Volume (P1 = 2.31 in.) = 11.458 acre-feet inches -- -- -- --
500-yr Runoff Volume (P1 = 3.14 in.) = 16.483 acre-feet inches -- -- -- --
Approximate 2-yr Detention Volume = 2.679 acre-feet ---- -- --
Approximate 5-yr Detention Volume = 3.966 acre-feet ---- -- --
Approximate 10-yr Detention Volume = 4.744 acre-feet -- -- -- --
Approximate 25-yr Detention Volume = 5.625 acre-feet -- -- -- --
Approximate 50-yr Detention Volume = 6.059 acre-feet -- -- -- --
Approximate 100-yr Detention Volume = 6.850 acre-feet -- -- -- --
-- -- -- --
Define Zones and Basin Geometry -- -- -- --
Select Zone 1 Storage Volume (Required) = acre-feet -- -- -- --
Select Zone 2 Storage Volume (Optional) = acre-feet -- -- -- --
Select Zone 3 Storage Volume (Optional) = acre-feet -- -- -- --
Total Detention Basin Volume = acre-feet -- -- -- --
Initial Surcharge Volume (ISV) = user ft 3 -- -- -- --
Initial Surcharge Depth (ISD) = user ft -- -- -- --
Total Available Detention Depth (Htotal) = user ft -- -- -- --
Depth of Trickle Channel (HTC) = user ft -- -- -- --
Slope of Trickle Channel (STC) = user ft/ft -- -- -- --
Slopes of Main Basin Sides (Smain) = user H:V -- -- -- --
Basin Length-to-Width Ratio (RL/W) = user -- -- -- --
-- -- -- --
Initial Surcharge Area (AISV) =user ft 2 -- -- -- --
Surcharge Volume Length (LISV) =user ft -- -- -- --
Surcharge Volume Width (WISV) =user ft -- -- -- --
Depth of Basin Floor (HFLOOR) =user ft -- -- -- --
Length of Basin Floor (LFLOOR) =user ft -- -- -- --
Width of Basin Floor (WFLOOR) =user ft -- -- -- --
Area of Basin Floor (AFLOOR) =user ft 2 -- -- -- --
Volume of Basin Floor (VFLOOR) =user ft 3 -- -- -- --
Depth of Main Basin (HMAIN) =user ft -- -- -- --
Length of Main Basin (LMAIN) =user ft -- -- -- --
Width of Main Basin (WMAIN) =user ft -- -- -- --
Area of Main Basin (AMAIN) =user ft 2 -- -- -- --
Volume of Main Basin (VMAIN) =user ft 3 -- -- -- --
Calculated Total Basin Volume (Vtotal) =user acre-feet -- -- -- --
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DETENTION BASIN STAGE-STORAGE TABLE BUILDER
Optional
Override
Area (ft 2)
Length
(ft)
Optional
Override
Stage (ft)
Stage
(ft)
Stage - Storage
Description
Area
(ft 2)
Width
(ft)
Montava Phase D
Pond 427
MHFD-Detention, Version 4.06 (July 2022)
Volume
(ft 3)
Volume
(ac-ft)
Area
(acre)
After providing required inputs above including 1-hour rainfall
depths, click 'Run CUHP' to generate runoff hydrographs using
the embedded Colorado Urban Hydrograph Procedure.
ExampleZone Configuration (Retention Pond)
Pond 427.xlsm, Basin 4/30/2024, 12:12 PM
1 User Defined Stage-Area Booleans for Message
1 Equal Stage-Area Inputs Watershed L:W
1 CountA Watershed Lc:L
Watershed Slope
0 Calc_S_TC Booleans for CUHP
1 CUHP Inputs Complete
H_FLOOR 1 CUHP Results Calculated
L_FLOOR_OTHER
0.00 ISV 0.00 ISV
0.00 Floor #N/A #N/A
#N/A Zone 1 #N/A #N/A
0.00 Zone 2 #N/A #N/A
0.00 Zone 3 #N/A #N/A
DETENTION BASIN STAGE-STORAGE TABLE BUILDER
MHFD-Detention, Version 4.06 (July 2022)
0.000
4.340
8.680
13.020
17.360
0.000
0.960
1.920
2.880
3.840
0.00 2.00 4.00 6.00 8.00
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Area (acres)Volume (ac-ft)
0
41900
83800
125700
167600
0
5
10
15
20
0.00 2.00 4.00 6.00 8.00
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Stage (ft)
Length (ft)Width (ft)Area (sq.ft.)
Pond 427.xlsm, Basin 4/30/2024, 12:12 PM
Project:
Basin ID:
Depth Increment = 1.00 ft
Watershed Information 4999.75 Top of Micropool -- 0.00 -- -- -- 172,456 3.959
Selected BMP Type =EDB 5000 -- 0.25 -- -- -- 173,026 3.972 43,185 0.991
Watershed Area = acres 5001 -- 1.25 -- -- -- 180,032 4.133 219,714 5.044
Watershed Length = ft 5002 -- 2.25 -- -- -- 187,141 4.296 403,301 9.259
Watershed Length to Centroid = ft -- -- -- --
Watershed Slope = ft/ft -- -- -- --
Watershed Imperviousness = percent -- -- -- --
Percentage Hydrologic Soil Group A = percent -- -- -- --
Percentage Hydrologic Soil Group B = percent -- -- -- --
Percentage Hydrologic Soil Groups C/D = percent -- -- -- --
Target WQCV Drain Time = hours Drain Time Too Short -- -- -- --
Location for 1-hr Rainfall Depths = Denver - Capitol Building -- -- -- --
-- -- -- --
-- -- -- --
Optional User Overrides -- -- -- --
Water Quality Capture Volume (WQCV) = acre-feet acre-feet -- -- -- --
Excess Urban Runoff Volume (EURV) = acre-feet acre-feet -- -- -- --
2-yr Runoff Volume (P1 = 0.83 in.) = acre-feet inches -- -- -- --
5-yr Runoff Volume (P1 = 1.09 in.) = acre-feet inches -- -- -- --
10-yr Runoff Volume (P1 = 1.33 in.) = acre-feet inches -- -- -- --
25-yr Runoff Volume (P1 = 1.69 in.) = acre-feet inches -- -- -- --
50-yr Runoff Volume (P1 = 1.99 in.) = acre-feet inches -- -- -- --
100-yr Runoff Volume (P1 = 2.31 in.) = acre-feet inches -- -- -- --
500-yr Runoff Volume (P1 = 3.14 in.) = acre-feet inches -- -- -- --
Approximate 2-yr Detention Volume = acre-feet -- -- -- --
Approximate 5-yr Detention Volume = acre-feet -- -- -- --
Approximate 10-yr Detention Volume = acre-feet -- -- ----
Approximate 25-yr Detention Volume = acre-feet -- -- ----
Approximate 50-yr Detention Volume = acre-feet -- -- ----
Approximate 100-yr Detention Volume = acre-feet -- -- -- --
-- -- -- --
Define Zones and Basin Geometry -- -- -- --
Select Zone 1 Storage Volume (Required) = acre-feet -- -- -- --
Select Zone 2 Storage Volume (Optional) = acre-feet -- -- -- --
Select Zone 3 Storage Volume (Optional) = acre-feet -- -- -- --
Total Detention Basin Volume = acre-feet -- -- -- --
Initial Surcharge Volume (ISV) = user ft 3 -- -- -- --
Initial Surcharge Depth (ISD) = user ft -- -- -- --
Total Available Detention Depth (Htotal) = user ft -- -- -- --
Depth of Trickle Channel (HTC) = user ft -- -- -- --
Slope of Trickle Channel (STC) = user ft/ft -- -- -- --
Slopes of Main Basin Sides (Smain) = user H:V -- -- -- --
Basin Length-to-Width Ratio (RL/W) = user -- -- -- --
-- -- -- --
Initial Surcharge Area (AISV) =ft 2 -- -- -- --
Surcharge Volume Length (LISV) =ft -- -- -- --
Surcharge Volume Width (WISV) =ft -- -- -- --
Depth of Basin Floor (HFLOOR) =ft -- -- -- --
Length of Basin Floor (LFLOOR) =ft -- -- -- --
Width of Basin Floor (WFLOOR) =ft -- -- -- --
Area of Basin Floor (AFLOOR) =ft 2 -- -- -- --
Volume of Basin Floor (VFLOOR) =ft 3 -- -- -- --
Depth of Main Basin (HMAIN) =ft -- -- -- --
Length of Main Basin (LMAIN) =ft -- -- -- --
Width of Main Basin (WMAIN) =ft -- -- -- --
Area of Main Basin (AMAIN) =ft 2 -- -- -- --
Volume of Main Basin (VMAIN) =ft 3 -- -- -- --
Calculated Total Basin Volume (Vtotal) =acre-feet -- -- -- --
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--------
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--------
--------
--------
--------
--------
--------
--------
--------
--------
--------
--------
--------
--------
--------
--------
--------
--------
--------
After providing required inputs above including 1-hour rainfall
depths, click 'Run CUHP' to generate runoff hydrographs using
the embedded Colorado Urban Hydrograph Procedure.
Volume
(ft 3)
Volume
(ac-ft)
Area
(acre)
DETENTION BASIN STAGE-STORAGE TABLE BUILDER
Optional
Override
Area (ft 2)
Length
(ft)
Optional
Override
Stage (ft)
Stage
(ft)
Stage - Storage
Description
Area
(ft 2)
Width
(ft)
Montava Phase D
Pond 427
MHFD-Detention, Version 4.06 (July 2022)
ExampleZone Configuration (Retention Pond)
Pond D.xlsm, Basin 4/30/2024, 12:16 PM
1 User Defined Stage-Area Booleans for Message
1 Equal Stage-Area Inputs Watershed L:W
0 CountA Watershed Lc:L
Watershed Slope
0 Calc_S_TC Booleans for CUHP
0 CUHP Inputs Complete
H_FLOOR CUHP Results Calculated
L_FLOOR_OTHER
0.00 ISV 0.00 ISV
0.00 Floor #N/A #N/A
#N/A Zone 1 #N/A #N/A
0.00 Zone 2 #N/A #N/A
0.00 Zone 3 #N/A #N/A
DETENTION BASIN STAGE-STORAGE TABLE BUILDER
MHFD-Detention, Version 4.06 (July 2022)
0.000
2.315
4.630
6.945
9.260
0.000
1.075
2.150
3.225
4.300
0.00 1.00 2.00 3.00 4.00
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Stage (ft.)
Area (acres)Volume (ac-ft)
0
46800
93600
140400
187200
0
5
10
15
20
0.00 1.00 2.00 3.00 4.00
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Stage (ft)
Length (ft)Width (ft)Area (sq.ft.)
Pond D.xlsm, Basin 4/30/2024, 12:16 PM
Project:
Basin ID:
Depth Increment = 1.00 ft
Watershed Information 4995 Top of Micropool -- 0.00 -- -- -- 0 0.000
Selected BMP Type =EDB 4996 -- 1.00 -- -- -- 9,338 0.214 4,668 0.107
Watershed Area = 20.66 acres 4997 -- 2.00 -- -- -- 22,249 0.511 20,462 0.470
Watershed Length = 1,695 ft 4998 -- 3.00 -- -- -- 40,852 0.938 52,012 1.194
Watershed Length to Centroid = 976 ft 4999 -- 4.00 -- -- -- 56,939 1.307 100,908 2.317
Watershed Slope = 0.020 ft/ft 5000 -- 5.00 -- -- -- 69,899 1.605 164,327 3.772
Watershed Imperviousness = 51.60% percent -- -- -- --
Percentage Hydrologic Soil Group A = 0.0% percent -- ---- --
Percentage Hydrologic Soil Group B = 0.0% percent -- ---- --
Percentage Hydrologic Soil Groups C/D = 100.0% percent -- -- -- --
Target WQCV Drain Time = 40.0 hours -- -- -- --
Location for 1-hr Rainfall Depths = Denver - Capitol Building -- -- -- --
-- -- -- --
-- -- -- --
Optional User Overrides -- -- -- --
Water Quality Capture Volume (WQCV) = 0.363 acre-feet acre-feet -- -- -- --
Excess Urban Runoff Volume (EURV) = 1.011 acre-feet acre-feet -- -- -- --
2-yr Runoff Volume (P1 = 0.83 in.) = 0.664 acre-feet inches -- -- -- --
5-yr Runoff Volume (P1 = 1.09 in.) = 0.991 acre-feet inches -- -- -- --
10-yr Runoff Volume (P1 = 1.33 in.) = 1.359 acre-feet inches -- -- -- --
25-yr Runoff Volume (P1 = 1.69 in.) = 2.054 acre-feet inches -- -- -- --
50-yr Runoff Volume (P1 = 1.99 in.) = 2.579 acre-feet inches -- -- -- --
100-yr Runoff Volume (P1 = 2.31 in.) = 3.209 acre-feet inches -- -- -- --
500-yr Runoff Volume (P1 = 3.14 in.) = 4.719 acre-feet inches -- -- -- --
Approximate 2-yr Detention Volume = 0.620 acre-feet ---- -- --
Approximate 5-yr Detention Volume = 0.962 acre-feet ---- -- --
Approximate 10-yr Detention Volume = 1.147 acre-feet -- -- -- --
Approximate 25-yr Detention Volume = 1.377 acre-feet -- -- -- --
Approximate 50-yr Detention Volume = 1.492 acre-feet -- -- -- --
Approximate 100-yr Detention Volume = 1.751 acre-feet -- -- -- --
-- -- -- --
Define Zones and Basin Geometry -- -- -- --
Select Zone 1 Storage Volume (Required) = acre-feet -- -- -- --
Select Zone 2 Storage Volume (Optional) = acre-feet -- -- -- --
Select Zone 3 Storage Volume (Optional) = acre-feet -- -- -- --
Total Detention Basin Volume = acre-feet -- -- -- --
Initial Surcharge Volume (ISV) = user ft 3 -- -- -- --
Initial Surcharge Depth (ISD) = user ft -- -- -- --
Total Available Detention Depth (Htotal) = user ft -- -- -- --
Depth of Trickle Channel (HTC) = user ft -- -- -- --
Slope of Trickle Channel (STC) = user ft/ft -- -- -- --
Slopes of Main Basin Sides (Smain) = user H:V -- -- -- --
Basin Length-to-Width Ratio (RL/W) = user -- -- -- --
-- -- -- --
Initial Surcharge Area (AISV) =user ft 2 -- -- -- --
Surcharge Volume Length (LISV) =user ft -- -- -- --
Surcharge Volume Width (WISV) =user ft -- -- -- --
Depth of Basin Floor (HFLOOR) =user ft -- -- -- --
Length of Basin Floor (LFLOOR) =user ft -- -- -- --
Width of Basin Floor (WFLOOR) =user ft -- -- -- --
Area of Basin Floor (AFLOOR) =user ft 2 -- -- -- --
Volume of Basin Floor (VFLOOR) =user ft 3 -- -- -- --
Depth of Main Basin (HMAIN) =user ft -- -- -- --
Length of Main Basin (LMAIN) =user ft -- -- -- --
Width of Main Basin (WMAIN) =user ft -- -- -- --
Area of Main Basin (AMAIN) =user ft 2 -- -- -- --
Volume of Main Basin (VMAIN) =user ft 3 -- -- -- --
Calculated Total Basin Volume (Vtotal) =user acre-feet -- -- -- --
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DETENTION BASIN STAGE-STORAGE TABLE BUILDER
Optional
Override
Area (ft 2)
Length
(ft)
Optional
Override
Stage (ft)
Stage
(ft)
Stage - Storage
Description
Area
(ft 2)
Width
(ft)
Montava Phase D
INTERIM POND
MHFD-Detention, Version 4.06 (July 2022)
Volume
(ft 3)
Volume
(ac-ft)
Area
(acre)
After providing required inputs above including 1-hour rainfall
depths, click 'Run CUHP' to generate runoff hydrographs using
the embedded Colorado Urban Hydrograph Procedure.
ExampleZone Configuration (Retention Pond)
SWALE POND.xlsm, Basin 4/30/2024, 12:15 PM
1 User Defined Stage-Area Booleans for Message
1 Equal Stage-Area Inputs Watershed L:W
1 CountA Watershed Lc:L
Watershed Slope
0 Calc_S_TC Booleans for CUHP
1 CUHP Inputs Complete
H_FLOOR 1 CUHP Results Calculated
L_FLOOR_OTHER
0.00 ISV 0.00 ISV
0.00 Floor #N/A #N/A
#N/A Zone 1 #N/A #N/A
0.00 Zone 2 #N/A #N/A
0.00 Zone 3 #N/A #N/A
DETENTION BASIN STAGE-STORAGE TABLE BUILDER
MHFD-Detention, Version 4.06 (July 2022)
0.000
0.945
1.890
2.835
3.780
0.000
0.405
0.810
1.215
1.620
0.00 1.50 3.00 4.50 6.00
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Area (acres)Volume (ac-ft)
0
17500
35000
52500
70000
0
5
10
15
20
0.00 1.50 3.00 4.50 6.00
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SWALE POND.xlsm, Basin 4/30/2024, 12:15 PM