HomeMy WebLinkAboutSANCTUARY ON THE GREEN - PDP210018 - SUBMITTAL DOCUMENTS - ROUND 1 - DRAINAGE REPORT
November 3, 2021
PRELIMINARY DRAINAGE AND
EROSION CONTROL REPORT FOR
SANCTUARY ON THE GREEN
Fort Collins, Colorado
Prepared for:
C & A Companies
7991 Shaffer Parkway, Suite 200
Littleton, Colorado 80127
Prepared by:
301 N. Howes, Suite 100
Fort Collins, Colorado 80521
Phone: 970.221.4158 Fax: 970.221.4159
www.northernengineering.com
Project Number: 1536-001
This Drainage Report is consciously provided as a PDF.
Please consider the environment before printing this document in its entirety.
When a hard copy is absolutely necessary, we recommend double-sided printing.
November 3, 2021
City of Fort Collins
Stormwater Utility
700 Wood Street
Fort Collins, Colorado 80521
RE: Preliminary Drainage and Erosion Control Report for
SANCTUARY ON THE GREEN
Dear Staff:
Northern Engineering is pleased to submit this Preliminary Drainage and Erosion Control Report
for your review. This report accompanies the Project Development Plan submittal for the
proposed Sanctuary on the Green development.
This report has been prepared in accordance to Fort Collins Stormwater Criteria Manual (FCSCM),
and serves to document the stormwater impacts associated with the proposed project. We
understand that review by the City is to assure general compliance with standardized criteria
contained in the FCSCM.
If you should have any questions as you review this report, please feel free to contact us.
Sincerely,
NORTHERN ENGINEERING SERVICES, INC.
Aaron Cvar, PhD, PE
Senior Engineer
Sanctuary on the Green
Preliminary Drainage Report
TABLE OF CONTENTS
I. GENERAL LOCATION AND DESCRIPTION ................................................................... 1
A. Location ............................................................................................................................................. 1
B. Description of Property ..................................................................................................................... 3
C. Floodplain.......................................................................................................................................... 5
II. DRAINAGE BASINS AND SUB-BASINS ....................................................................... 6
A. Major Basin Description .................................................................................................................... 6
B. Sub-Basin Description ....................................................................................................................... 6
III. DRAINAGE DESIGN CRITERIA ................................................................................... 6
A. Regulations........................................................................................................................................ 6
B. Four Step Process .............................................................................................................................. 6
C. Development Criteria Reference and Constraints ............................................................................ 7
D. Hydrological Criteria ......................................................................................................................... 7
E. Hydraulic Criteria ............................................................................................................................ 10
F. Modifications of Criteria ................................................................................................................. 10
IV. DRAINAGE FACILITY DESIGN .................................................................................. 10
A. General Concept ............................................................................................................................. 10
B. Specific Details ................................................................................................................................ 11
V. CONCLUSIONS ...................................................................................................... 13
A. Compliance with Standards ............................................................................................................ 13
B. Drainage Concept ............................................................................................................................ 13
APPENDICES:
APPENDIX A – Hydrologic Computations, Offsite Drainage Exhibit
APPENDIX B – USDA Soils Information
APPENDIX C – Water Quality and LID Computations and Information
APPENDIX D – Detention Computations, SWMM Output
APPENDIX E – Erosion Control Report
Sanctuary on the Green
Preliminary Drainage Report
LIST OF FIGURES:
Figure 1 – Aerial Photograph ................................................................................................ 3
Figure 2– Proposed Site Plan ................................................................................................ 4
Figure 3 – Existing Floodplains ............................................................................................. 5
MAP POCKET:
Proposed Drainage Exhibit
Sanctuary on the Green
Preliminary Drainage Report 1
I. GENERAL LOCATION AND DESCRIPTION
A. Location
1. Vicinity Map
2. The project site is located in the northeast quarter of Section 9, Township 7 North,
Range 69 West of the 6th Principal Meridian, City of Fort Collins, County of Larimer,
State of Colorado.
3. The project site is located just northwest of the intersection of Taft Hill Road and
Laporte Avenue.
4. The New Mercer Canal traverses the site and receives a portion of historic flow from a
portion of the site. Additionally, the Larimer No. 2 Canal is located just to the east of
the site and receives historic flows from the site via an existing culvert under Taft Hill
Road. The proposed drainage plan routes developed flows under the New Mercer
Canal and directs all developed flows from the site into the Larimer No. 2. Initial
discussions have been held with the Larimer No. 2 Ditch Company to explain this
proposed concept and to get feedback from the ditch company. Based on our initial
discussions, the ditch company will accept developed runoff from the project site, as
long as water quality treatment and detention are provided. The ditch company has
Sanctuary on the Green
Preliminary Drainage Report 2
initially requested a peak 100-year detained release rate of no greater than 15 cfs
from the overall site, which is a little over half of the capacity of the existing 24-inch
culvert under Taft Hill Road. We will continue dialogue with the ditch company and
ensure ditch company review and approval of the proposed drainage plan and release
into the ditch.
5. The proposed site design will include both LID and Extended Detention water quality
treatment prior to stormwater discharge from the site. Water quality treatment
methods are described in further detail below.
6. Existing residential developments, Bellwether Farm, and Green Acres exist to the
north of the site; several estate lots exist to the south of the site.
7. Offsite flows enter the site from the west and south. These flows are generated by
basins which have been identified in the West Vine Basin Plan (Ref.6). Ultimately,
flows from these offsite basins will be conveyed through the site by a regional channel
running through the center of the site and then along the northern portion of the site.
8. Accommodation for the future regional channel has been made with the currently
proposed site plan, which provides large open space tracts running through the
central portion, and northern portions of the site. These open space tracts will be
used for detention in the interim period between now and when the regional channel
is completed. When the regional channel is in place, onsite detention will not be
necessary, as the regional channel will serve as the outfall for the project site and will
convey fully developed onsite flows.
9. As part of the future anticipated regional channel, a large box culvert will be put in
place with the proposed project. Just upstream of the box culvert, we are proposing
interim detention by means of partially blocking the box culvert with a concrete wall.
When the regional channel is completed in the future, the concrete wall will be
removed to allow full regional flow through the culvert.
Sanctuary on the Green
Preliminary Drainage Report 3
B. Description of Property
1. The overall development area is roughly 43 acres in size.
Figure 1 – Aerial Photograph
2. The subject property is currently composed of undeveloped land. Existing ground
slopes are mild to moderate (i.e., 1 - 6±%) through the interior of the property.
Historic drainage patterns direct flows generally from southwest to northeast and have
historically been conveyed into a culvert under Taft Hill Road. This has historically
conveyed site runoff into the Larimer No. 2 Ditch.
3. According to the United States Department of Agriculture (USDA) Natural Resources
Conservation Service (NRCS) Soil Survey website:
http://websoilsurvey.nrcs.usda.gov/app/WebSoilSurvey.aspx,
the site primarily consists of Nunn Clay Loam, which falls into Hydrologic Soil Group
C.
4. The proposed project site plan is composed of single family, duplexes, and multi-
family residential development. Associated site work, water, and sewer lines will be
constructed with the development. Onsite detention water quality treatment is
proposed and will consist of several features which are discussed in Section IV.
PROJECT
SITE
Sanctuary on the Green
Preliminary Drainage Report 4
N.T.S.
Figure 2– Proposed Site Plan
5. The New Mercer Canal crosses the site.
6. The proposed land use is single family, duplexes, and multi-family residential.
Sanctuary on the Green
Preliminary Drainage Report 5
C. Floodplain
1. The project site is not encroached by any FEMA jurisdictional flood zone; however,
the site is encroached by City designated West Vine Basin flood zones, as shown in
Figure 3, below.
2. Icon Engineering is conducting all floodplain modeling and will submit a floodplain
modeling report separately. Please refer to this study for all pertinent floodplain
modeling information.
Figure 3 –Area Floodplain Mapping
3. A Critical Facilities are not allowed in the floodplain.
4. Portions of the site are currently shown in the West Vine flood fringe.
5. A City CLOMR / LOMR process will be undertaken to remap the portions of the site
that are currently shown in floodway and flood fringe. Fill is proposed which will
move flood boundaries, and by going through the City CLOMR / LOMR process, we
will revise boundaries accordingly. Icon Engineering is conducting all floodplain
modeling and will submit a floodplain modeling report separately. Please refer to this
study for all pertinent floodplain modeling information.
6. Once the CLOMR is completed, no structures will be shown within floodway or flood
fringe areas.
7. The vertical datum utilized for site survey work is the City of Fort Collins Benchmark
#33-97 (Elevation=5088.19; NAVD 88). Icon Engineering is conducting all
floodplain modeling and will submit a floodplain modeling report separately. Please
PROJECT SITE
Sanctuary on the Green
Preliminary Drainage Report 6
refer to this study for all pertinent floodplain modeling information.
8. A floodplain use permit will be required for each site construction element (detention
ponds, bike paths, parking lots, utilities, etc.) in the floodplain.
9. Ultimately upon completion of construction, a LOMR will be submitted. Icon
Engineering is conducting all floodplain modeling and will submit a floodplain
modeling report separately. Icon will submit the LOMR at the end of the construction
phase of the project.
II. DRAINAGE BASINS AND SUB-BASINS
A. Major Basin Description
1. The project site lies within the West Vine Master Drainage Basin. Onsite detention is
required for the runoff volume difference between the 100-year developed inflow rate
and the historic 2-year rate.
2. The New Mercer Canal traverses the site and receives a portion of historic flow from a
portion of the site. Additionally, the Larimer No. 2 Canal is located just to the east of
the site and receives historic flows from the site via an existing culvert under Taft Hill
Road. The proposed drainage plan routes developed flows under the New Mercer
Canal, and directs all developed flows from the site into the Larimer No. 2. Initial
discussions have been held with the Larimer No. 2 Ditch Company to explain this
proposed concept and to get feedback from the ditch company. Based on our initial
discussions, the ditch company will accept developed runoff from the project site, as
long as water quality treatment and detention is provided. The ditch company has
initially requested a peak 100-year detained release rate of no greater than 15 cfs
from the overall site, which is a little over half of the capacity of the existing 24-inch
culvert under Taft Hill Road. We will continue dialogue with the ditch company and
ensure ditch company review and approval of the proposed drainage plan and release
into the ditch.
B. Sub-Basin Description
1. Historic drainage patterns direct flows generally from southwest to northeast, and
have historically been conveyed into the New Mercer Canal and the Larimer No. 2
Canal.
2. A more detailed description of the project drainage patterns is provided below.
III. DRAINAGE DESIGN CRITERIA
A. Regulations
There are no optional provisions outside of the FCSCM proposed with the proposed
project.
B. Four Step Process
The overall stormwater management strategy employed with the proposed project utilizes
the “Four Step Process” to minimize adverse impacts of urbanization on receiving waters.
The following is a description of how the proposed development has incorporated each
step.
Sanctuary on the Green
Preliminary Drainage Report 7
Step 1 – Employ Runoff Reduction Practices
Several techniques have been utilized with the proposed development to facilitate the
reduction of runoff peaks, volumes, and pollutant loads as the site is developed from the
current use by implementing multiple Low Impact Development (LID) strategies including:
Conserving existing amenities in the site including the existing vegetated areas.
Providing vegetated open areas throughout the site to reduce the overall impervious
area and to minimize directly connected impervious areas (MDCIA).
Routing flows, to the extent feasible, through vegetated swales to increase time of
concentration, promote infiltration and provide initial water quality.
Step 2 – Implement BMPs That Provide a Water Quality Capture Volume (WQCV) with
Slow Release
The efforts taken in Step 1 will facilitate the reduction of runoff; however, urban
development of this intensity will still generate stormwater runoff that will require
additional BMPs and water quality. The majority of stormwater runoff from the site will
ultimately be intercepted and treated using detention and LID treatment methods prior to
exiting the site.
Step 3 – Stabilize Drainageways
There are no major drainageways within the subject property. While this step may not
seem applicable to proposed development, the project indirectly helps achieve stabilized
drainageways nonetheless. By providing water quality treatment, where none previously
existed, sediment with erosion potential is removed from downstream drainageway
systems. Furthermore, this project will pay one-time stormwater development fees, as
well as ongoing monthly stormwater utility fees, both of which help achieve City-wide
drainageway stability.
Step 4 – Implement Site Specific and Other Source Control BMPs.
The proposed project will improve upon site specific source controls compared to historic
conditions:
The proposed development will provide LID and water quality treatment; thus,
eliminating sources of potential pollution previously left exposed to weathering and
runoff processes.
C. Development Criteria Reference and Constraints
The subject property is surrounded by currently developed properties. Thus, several
constraints have been identified during the course of this analysis that will impact the
proposed drainage system including:
Existing elevations along the property lines will generally be maintained.
As previously mentioned, overall drainage patterns of the existing site will be
maintained.
Elevations of existing downstream facilities that the subject property will release to
will be maintained.
D. Hydrological Criteria
1. The City of Fort Collins Rainfall Intensity-Duration-Frequency Curves, as depicted in
Figure 3.4-1 of the FCSCM, serve as the source for all hydrologic computations
associated with the proposed development. Tabulated data contained in Table 3.4-1
Sanctuary on the Green
Preliminary Drainage Report 8
has been utilized for Rational Method runoff calculations.
Figure 3.4-1 –Rainfall IDF Curve (City of Fort Collins Stormwater Criteria Manual, Ref.1)
Sanctuary on the Green
Preliminary Drainage Report 9
Table 3.4-1 –Rainfall IDF Curve (City of Fort Collins Stormwater Criteria Manual, Ref.1)
2. Three separate design storms have been utilized to address distinct drainage
Sanctuary on the Green
Preliminary Drainage Report 10
scenarios. A fourth design storm has also been computed for comparison purposes.
The first design storm considered is the 80th percentile rain event, which has been
employed to design the project’s water quality features. The second event analyzed is
the “Minor,” or “Initial” Storm, which has a 2-year recurrence interval. The third
event considered is the “Major Storm,” which has a 100-year recurrence interval.
The fourth storm computed, for comparison purposes only, is the 10-year event.
3. No other assumptions or calculation methods have been used with this development
that are not referenced by current City of Fort Collins criteria.
E. Hydraulic Criteria
1. As previously noted, the subject property maintains historic drainage patterns.
2. All drainage facilities proposed with the project are designed in accordance with
criteria outlined in the FCSCM and/or the Urban Drainage and Flood Control District
(UDFCD) Urban Storm Drainage Criteria Manual.
3. As stated above, the subject property is not located in a FEMA designated floodplain.
However, the project does lie within a City designated floodplain and floodway. The
proposed project does not propose to modify any natural drainageways.
F. Modifications of Criteria
1. The proposed development is not requesting any modifications to criteria at this time.
IV. DRAINAGE FACILITY DESIGN
A. General Concept
1. The main objectives of the project drainage design are to maintain existing drainage
patterns, and to ensure no adverse impacts to any adjacent properties.
2. LID treatment will be provided in the form of Rain Gardens and StormTech chamber
systems upstream of each detention pond, as discussed further below.
3. Drainage patterns anticipated for drainage basins shown in the Drainage Exhibit are
described below. Drainage basins have been defined for preliminary design purposes
and are subject to change at Final design; however, general drainage patterns and
concepts are not expected to be significantly altered.
Basins A1 – A8
Basins A1 through A8 consist of single family areas, duplex areas, and open space.
Drainage from these basins will be conveyed via street curb and gutter, as well as
alleyway sections to proposed storm sewer systems. Ultimately, storm systems will
direct developed runoff into Pond 1, which will provide water quality and detention
and of developed runoff. Pond 1 will discharge into Pond 2, through a controlled
outlet structure and pipe. Pre-treatment will also be provided by a proposed
underground chamber system as discussed in Section IV.B, below.
Basins B1 – B5
Basins B1 through B5 consist of multi-family areas, and open space. Drainage from
these basins will be conveyed via street curb and gutter, as well as alleyway sections
to proposed storm sewer systems. Ultimately, storm systems will direct developed
runoff into Pond 2, which will provide detention of developed runoff. Pond 2 will
discharge into Pond 3, through a controlled outlet structure and pipe which will
Sanctuary on the Green
Preliminary Drainage Report 11
convey flows underneath the New Mercer Canal. Pre-treatment will also be provided
by a proposed underground chamber system, and a raingarden, as discussed in
Section IV.B, below.
Basins C1 – C4, C8
Basins C1 through C4, and C8 consist of single family attached areas and open space.
Drainage from these basins will be conveyed via street curb and gutter, as well as
alleyway sections to proposed storm sewer systems. Ultimately, storm systems will
direct developed runoff into Pond 3, which will provide detention of developed runoff.
Pond 3 will discharge through a controlled outlet structure and pipe which will convey
flows underneath Taft Hill Road. This pipe discharges into a short reach of open
swale conveying flows east directly into the Larimer No. 2 Canal. Pre-treatment will
also be provided by a proposed underground chamber system as discussed in Section
IV.B, below.
Basins C5 – C7
Basins C5 through C8 consists of single family attached areas and open space.
Drainage from this basin will be conveyed via street curb and gutter, as well as
alleyway sections into Pond 5, which will provide detention of developed runoff. Water
quality for Basins C5 and C6 will be provided using raingardens. Pond 5 will
discharge into Pond 3 via a controlled outlet structure and pipe. Pre-treatment will be
provided by a series of raingardens, as discussed in Section IV.B, below.
Basins D1 – D4
Basins D1 through D4 consist of single family attached areas, and open space.
Drainage from these basins will be conveyed via street curb and gutter, as well as
alleyway sections to proposed storm sewer systems. Ultimately, storm systems will
direct developed runoff into Pond 4, which will provide detention of developed runoff.
Water quality for Basins D2, D3, D4, and D5 will be provided using raingardens.
Pond 4 will discharge directly into Pond 5. Pond 5 will discharge into Pond 3 via a
controlled outlet structure and pipe. Pre-treatment will also be provided by a series of
raingardens, as discussed in Section IV.B, below.
A full-size copy of the Drainage Exhibit can be found in the Map Pocket at the end of
this report.
B. Specific Details
1. Five detention basins are proposed throughout the site, and will detain up to
the 100-year storm event. Ponds 1, 2, 4 and 5 route through to Pond 3
which will discharge into the Larimer No. 2 Canal. As shown on the Historic
Drainage Exhibit provided in Appendix A, the overall historic drainage area
from the site is 41.35 acres. Based on criteria for the West Vine Basin, an
allowable discharge rate of 0.35 cfs per acre translates to 14.47. Based on
initial discussions with the Larimer No. 2 Ditch Company, the ditch company
will accept developed runoff from the project site, as long as water quality
treatment and detention is provided. The ditch company has initially
requested a peak 100-year detained release rate of no greater than 15 cfs
from the overall site, which is a little over half of the capacity of the existing
Sanctuary on the Green
Preliminary Drainage Report 12
24-inch culvert under Taft Hill Road.
2. The proposed detention system will control overall site release at or below a
peak discharge rate of 15 cfs, as initially agreed to by the Larimer No. 2 Ditch
Company. Detention pond performance has been modeled in the computer
program EPA-SWMM.
3. Table 4 summarizes results of preliminary SWMM modeling. Please see
SWMM modeling output and detention design information provided in
Appendix D. As noted, the maximum allowable release rate from the overall
site is based on initial discussion with the Larimer No. 2 Ditch Company and
is subject to change, which could result in additional detention volume being
needed.
TABLE 4 – Pond Summary Table
4. Rain Gardens (designed as porous landscape detention (PLD) holding cells) are
proposed as the primary LID treatment method for the site. The PLD’s will provide
standard 12-hour porous landscape detention (PLD) treatment. Additionally,
StormTech chamber systems will be provided at locations shown on the Drainage
Exhibit, as a pre-treatment measure prior to discharge into detention systems.
Please see the LID summary table, LID computations, and the LID Exhibit provided in
Appendix C.
5. Water quality capture volume will be incorporated in the lower stage of some
of the ponds, providing 40-hour extended detention for a portion of the site.
Please see Water Quality computations provided in Appendix C for a summary
of water quality capture volume and ponds providing this component of
treatment.
6. Final design details, and construction documentation shall be provided to the
City of Fort Collins for review prior to Final Development Plan approval.
7. Stormwater facility Standard Operating Procedures (SOP) will be provided in
the Development Agreement.
Pond ID
100-Yr.
Detention
Vol. (Ac-Ft)
Water Quality
Capture Volume
(Ac-Ft)
Total
Req'd Vol.
(Ac-Ft)
Peak
Release
(cfs)
Pond 1 0.95 N/A 0.47 15.80
Pond 2 3.71 N/A 3.71 15.50
Pond 3 4.01 0.48 4.49 14.90
Pond 4 0.35 N/A 0.35 5.70
Pond 5 0.47 N/A 0.47 5.60
POND SUMMARY TABLE
Sanctuary on the Green
Preliminary Drainage Report 13
V. CONCLUSIONS
A. Compliance with Standards
1. The drainage design proposed with the proposed project complies with the City of Fort
Collins’ Stormwater Criteria Manual.
2. The drainage design proposed with this project complies with requirements for the
West Vine Basin Master Plan.
3. The drainage plan and stormwater management measures proposed with the
proposed development are compliant with all applicable State and Federal regulations
governing stormwater discharge.
B. Drainage Concept
1. The drainage design proposed with this project will effectively limit any potential
damage associated with its stormwater runoff by providing detention and water
quality mitigation features.
2. The drainage concept for the proposed development is consistent with requirements
for the West Vine Basin Master Plan.
Sanctuary on the Green
Preliminary Drainage Report 14
References
1. Fort Collins Stormwater Criteria Manual, City of Fort Collins, Colorado, December 2018.
2. Larimer County Urban Area Street Standards, Adopted January 2, 2001, Repealed and
Reenacted, Effective October 1, 2002, Repealed and Reenacted, Effective April 1, 2007.
3. Soils Resource Report for Larimer County Area, Colorado, Natural Resources Conservation
Service, United States Department of Agriculture
(https://websoilsurvey.sc.egov.usda.gov/App/ Data upload February 2019)
4. Urban Storm Drainage Criteria Manual, Volumes 1-3, Urban Drainage and Flood Control
District, Wright-McLaughlin Engineers, Denver, Colorado, Revised April 2008.
5. West Vine Basin MODSWMM Conversion and Hydrologic Update, Icon Engineering, Inc.,
Janu
APPENDIX A
Hydrologic Computations, Historic Drainage Exhibit
CHARACTER OF SURFACE: Runoff
Coefficient
Percentage
Impervious Project:1536-001
Streets, Parking Lots, Roofs, Alleys, and Drives:Calculations By:ATC
Asphalt ……....……………...……….....…...……………….…………………………………..0.95 100%Date:
Concrete …….......……………….….……….………………..….…………………………………0.95 90%
Gravel ……….…………………….….…………………………..………………………………..0.50 40%
Roofs …….…….………………..……………….…………………………………………….. 0.95 90%
Pavers…………………………...………………..……………………………………………..0.50 40%
Lawns and Landscaping
Sandy Soil ……..……………..……………….……………………………………………..0.15 0%
Clayey Soil ….….………….…….…………..……………………………………………….0.25 0%2-year Cf = 1.00 100-year Cf = 1.25
Basin ID Basin Area
(s.f.)
Basin Area
(ac)
Area of
Asphalt
(ac)
Area of
Concrete
(ac)
Area of
Roofs
(ac)
Area of
Pavers
(ac)
Area of
Lawn, Rain
Garden, or
Landscaping
(ac)
2-year
Composite
Runoff
Coefficient
10-year
Composite
Runoff
Coefficient
100-year
Composite
Runoff
Coefficient
Composite
% Imperv.
H1 1215324 27.90 0.00 0.00 0.00 0.00 27.90 0.25 0.25 0.31 0%
H2 585882 13.45 0.00 0.00 0.00 0.00 13.45 0.25 0.25 0.31 0%
HISTORIC % IMPERVIOUSNESS AND RUNOFF COEFFICIENT CALCULATIONS
Runoff Coefficients have been estimated for preliminary purposes and are taken from the City of Fort Collins Storm Drainage Design Criteria and Construction Standards, Table 3-3. % Impervious taken from UDFCD
USDCM, Volume I.
10-year Cf = 1.00
July 15, 2019
Overland Flow, Time of Concentration:
1536-001
Gutter/Swale Flow, Time of Concentration:
Tt = L / 60V
Tc = Ti + Tt (Equation RO-2)
Velocity (Gutter Flow), V = 20·S½
Velocity (Swale Flow), V = 15·S½
NOTE: C-value for overland flows over grassy surfaces; C = 0.25
Is Length
>500' ?
C*Cf
(2-yr
Cf=1.00)
C*Cf
(10-yr
Cf=1.00)
C*Cf
(100-yr
Cf=1.25)
Length,
L
(ft)
Slope,
S
(%)
Ti
2-yr
(min)
Ti
10-yr
(min)
Ti
100-yr
(min)
Length,
L
(ft)
Slope,
S
(%)
Velocity,
V
(ft/s)
Tt
(min)
Length,
L
(ft)
Slope,
S
(%)
Velocity,
V
(ft/s)
Tt
(min)
2-yr
Tc
(min)
10-yr
Tc
(min)
100-yr
Tc
(min)
H1 H1 No
0.25 0.25 0.31 265 1.10% 25.1 25.1 23.2 0 0.00% N/A 0.0 1270 0.90% 1.42 14.9 39.9 39.9 38.1
H2 H2 No
0.25 0.25 0.31 180 1.60% 18.2 18.2 16.9 0 0.00% N/A 0.0 710 1.20% 1.64 7.2 25.4 25.4 24.1
HISTORIC TIME OF CONCENTRATION COMPUTATIONS
Gutter Flow Swale Flow
Design
Point Basin
Overland Flow
ATC
July 15, 2019
Time of Concentration
(Equation RO-4)
()
3
1
*1.187.1
S
LCfCTi
-=
Rational Method Equation:Project:1536-001
Calculations By:
Date:
From Section 3.2.1 of the CFCSDDC
Rainfall Intensity:
H1 H1 27.90
40 40 38 0.25 0.25 0.31 1.08 1.85 3.87 7.53 12.87 33.74
H2 H2 13.45
25 25 24 0.25 0.25 0.31 1.43 2.44 5.09 4.81 8.20 21.39
Area, A
(acres)
Intensity,
i2
(in/hr)
100-yr
Tc
(min)
HISTORIC RUNOFF COMPUTATIONS
C100
Design
Point
Flow,
Q100
(cfs)
Flow,
Q2
(cfs)
10-yr
Tc
(min)
2-yr
Tc
(min)
C2
Flow,
Q10
(cfs)
Intensity,
i100
(in/hr)
Basin(s)
ATC
July 15, 2019
Intensity,
i10
(in/hr)
Rainfall Intensity taken from the City of Fort Collins Storm Drainage Design Criteria (CFCSDDC), Figure 3.1
C10
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E
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TTCELEC
CABL
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ITCHH1
H2H2H1NORTH( IN FEET )1 inch = ft.Feet0200200200400600HISTORIC DRAINAGE EXHIBITENGINEERNGIEHTRONRN02-13-19D:\PROJECTS\1536-001\DWG\DRNG\1536-001_HISTDRNG.DWG
CHARACTER OF SURFACE: Runoff
Coefficient
Percentage
Impervious Project:1536-001
Streets, Parking Lots, Roofs, Alleys, and Drives:Calculations By:CLU
Asphalt ……....……………...……….....…...……………….…………………………………..0.95 100%Date:
Concrete …….......……………….….……….………………..….…………………………………0.95 90%
Gravel ……….…………………….….…………………………..………………………………..0.50 40%
Roofs …….…….………………..……………….…………………………………………….. 0.95 90%
Pavers…………………………...………………..……………………………………………..0.50 40%
Lawns and Landscaping
Sandy Soil ……..……………..……………….……………………………………………..0.15 0%
Clayey Soil ….….………….…….…………..……………………………………………….0.25 0%2-year Cf = 1.00 100-year Cf = 1.25
Basin ID Basin Area
(s.f.)
Basin Area
(ac)
Area of
Asphalt
(ac)
Area of
Concrete
(ac)
Area of
Roofs
(ac)
Area of
Pavers
(ac)
Area of
Lawn, Rain
Garden, or
Landscaping
(ac)
2-year
Composite
Runoff
Coefficient
10-year
Composite
Runoff
Coefficient
100-year
Composite
Runoff
Coefficient
Composite
% Imperv.
A1 125453 2.88 0.00 0.00 0.00 0.00 2.88 0.25 0.25 0.31 0%
A2 38333 0.88 0.41 0.11 0.26 0.00 0.10 0.87 0.87 1.00 85%
A3 13504 0.31 0.15 0.04 0.09 0.00 0.03 0.87 0.87 1.00 85%
A4 38768 0.89 0.42 0.11 0.27 0.00 0.10 0.87 0.87 1.00 85%
A5 96268 2.21 1.04 0.27 0.66 0.00 0.24 0.87 0.87 1.00 85%
A6 41818 0.96 0.45 0.12 0.29 0.00 0.11 0.87 0.87 1.00 85%
A7 49223 1.13 0.53 0.14 0.34 0.00 0.12 0.87 0.87 1.00 85%
A8 22869 0.53 0.25 0.06 0.16 0.00 0.06 0.87 0.87 1.00 85%
B1 104980 2.41 0.00 0.00 0.00 0.00 2.41 0.25 0.25 0.31 0%
B2 134165 3.08 0.60 0.37 0.89 0.00 1.22 0.67 0.67 0.84 56%
B3 84942 1.95 0.92 0.23 0.59 0.00 0.21 0.87 0.87 1.00 85%
B4 46609 1.07 0.00 0.00 0.00 0.00 1.07 0.87 0.87 1.00 0%
B5 71438 1.64 0.77 0.20 0.49 0.00 0.18 0.87 0.87 1.00 85%
C1 158123 3.63 0.00 0.00 0.00 0.00 3.63 0.25 0.25 0.31 20%
C2 94961 2.18 1.02 0.26 0.65 0.00 0.24 0.87 0.87 1.00 85%
C3 47480 1.09 0.05 0.02 0.11 0.00 0.90 0.87 0.87 1.00 85%
C4 47480 1.09 0.51 0.13 0.33 0.00 0.12 0.87 0.87 1.00 85%
C5 101059 2.32 1.09 0.28 0.70 0.00 0.25 0.87 0.87 1.00 85%
C6 92478 2.12 1.00 0.25 0.64 0.00 0.23 0.87 0.87 1.00 85%
C7 95832 2.20 1.03 0.26 0.66 0.00 0.24 0.87 0.87 1.00 85%
C8 30492 0.70 0.33 0.08 0.21 0.00 0.08 0.87 0.87 1.00 85%
D1 101059 2.32 0.23 0.28 0.70 0.00 1.11 0.61 0.61 0.77 48%
D2 56628 1.30 0.61 0.16 0.39 0.00 0.14 0.87 0.87 1.00 85%
D3 73181 1.68 0.79 0.20 0.37 0.00 0.32 0.82 0.82 1.00 78%
D4 40511 0.93 0.44 0.11 0.28 0.00 0.10 0.87 0.87 1.00 85%
DEVELOPED % IMPERVIOUSNESS AND RUNOFF COEFFICIENT CALCULATIONS
Runoff Coefficients have been estimated for preliminary purposes and are taken from the City of Fort Collins Storm Drainage Design Criteria and Construction Standards, Table 3-3. % Impervious taken from UDFCD
USDCM, Volume I.
10-year Cf = 1.00
November 3, 2021
Overland Flow, Time of Concentration:
Project:1536-001
Calculations By:
Date:
Gutter/Swale Flow, Time of Concentration:
Tt = L / 60V
Tc = Ti + Tt (Equation RO-2)
Velocity (Gutter Flow), V = 20·S½
Velocity (Swale Flow), V = 15·S½
NOTE: C-value for overland flows over grassy surfaces; C = 0.25
Is Length
>500' ?
C*Cf
(2-yr
Cf=1.00)
C*Cf
(10-yr
Cf=1.00)
C*Cf
(100-yr
Cf=1.25)
Length,
L
(ft)
Slope,
S
(%)
Ti
2-yr
(min)
Ti
10-yr
(min)
Ti
100-yr
(min)
Length,
L
(ft)
Slope,
S
(%)
Velocity,
V
(ft/s)
Tt
(min)
Length,
L
(ft)
Slope,
S
(%)
Velocity,
V
(ft/s)
Tt
(min)Tc Check
2-yr
Tc
(min)
10-yr
Tc
(min)
100-yr
Tc
(min)
A1 A1 No
0.25 0.25 0.31 82 2.00% 11.4 11.4 10.6 0 0.00% N/A N/A 0 0.00% N/A N/A 10.5 10.5 10.5 10.5
A2 A2 No
0.25 0.25 0.31 15 2.00% 4.9 4.9 4.5 320 1.60% 2.53 2.1 0 0.00% N/A N/A 11.9 7.0 7.0 6.6
A3 A3 No
0.25 0.25 0.31 18 2.00% 5.4 5.4 5.0 180 2.10% 2.90 1.0 0 0.00% N/A N/A 11.1 6.4 6.4 6.0
A4 A4 No
0.25 0.25 0.31 48 2.00% 8.7 8.7 8.1 0 0.50% N/A N/A 0 0.00% N/A N/A 10.3 8.7 8.7 8.1
A5 A5 No
0.25 0.25 0.31 70 2.00% 10.6 10.6 9.8 260 1.80% 2.68 1.6 0 0.00%N/A N/A 11.8 11.8 11.8 11.4
A6 A6 No
0.25 0.25 0.31 55 2.00% 9.4 9.4 8.7 210 1.10% 2.10 1.7 0 0.00% N/A N/A 11.5 11.0 11.0 10.3
A7 A7 No
0.25 0.25 0.31 30 2.00% 6.9 6.9 6.4 420 0.60% 1.55 4.5 0 0.00% N/A N/A 12.5 11.4 11.4 10.9
A8 A8 No
0.25 0.25 0.31 45 2.00% 8.5 8.5 7.8 315 0.50% 1.41 3.7 0 0.00% N/A N/A 12.0 12.0 12.0 11.6
B1 B1 No
0.25 0.25 0.31 0 2.00% N/A N/A N/A 0 0.50% N/A N/A 750 0.50% 1.06 11.8 10.0 10.0 10.0 10.0
B2 B2 No
0.25 0.25 0.31 80 2.00% 11.3 11.3 10.5 350 1.00% 2.00 2.9 0 0.00% N/A N/A 12.4 12.4 12.4 12.4
B3 B3 No
0.25 0.25 0.31 28 2.00% 6.7 6.7 6.2 450 0.50% 1.41 5.3 0 0.00% N/A N/A 12.7 12.0 12.0 11.5
B4 B4 No
0.25 0.25 0.31 55 2.00% 9.4 9.4 8.7 0 0.00% N/A N/A 250 0.50% 1.06 3.9 10.3 10.3 10.3 10.3
B5 B5 No
0.25 0.25 0.31 67 2.00% 10.3 10.3 9.6 207 0.60% 1.55 2.2 0 0.00%N/A N/A 11.5 11.5 11.5 11.5
C1 C1 No
0.25 0.25 0.31 80 2.00% 11.3 11.3 10.5 0 0.00% N/A N/A 0 0.00% N/A N/A 10.4 10.4 10.4 10.4
C2 C2 No
0.25 0.25 0.31 72 2.00% 10.7 10.7 9.9 570 1.10% 2.10 4.5 0 0.00%N/A N/A 13.6 13.6 13.6 13.6
C3 C3 No
0.25 0.25 0.31 115 2.00% 13.5 13.5 12.5 260 0.80% 1.79 2.4 0 0.00% N/A N/A 12.1 12.1 12.1 12.1
C4 C4 No
0.25 0.25 0.31 15 2.00% 4.9 4.9 4.5 0 0.00% N/A N/A 0 0.00% N/A N/A 10.1 5.0 5.0 5.0
C5 C5 No
0.25 0.25 0.31 20 2.00% 5.6 5.6 5.2 0 0.00% N/A N/A 0 0.00% N/A N/A 10.1 5.6 5.6 5.2
C6 C6 No
0.25 0.25 0.31 21 2.00% 5.8 5.8 5.4 0 0.00% N/A N/A 0 0.00% N/A N/A 10.1 5.8 5.8 5.4
C7 C7 No
0.25 0.25 0.31 100 2.00% 12.6 12.6 11.7 0 0.00% N/A N/A 0 0.00% N/A N/A 10.6 10.6 10.6 10.6
C8 C8 No
0.25 0.25 0.31 23 2.00% 6.1 6.1 5.6 0 0.00% N/A N/A 0 0.00% N/A N/A 10.1 6.1 6.1 5.6
D1 D1 No
0.25 0.25 0.31 0 2.00% N/A N/A N/A 0 0.00% N/A N/A 520 0.50% 1.06 8.2 10.0 8.2 8.2 8.2
D2 D2 No
0.25 0.25 0.31 0 2.00% N/A N/A N/A 900 0.50% 1.41 10.6 0 0.00% N/A N/A 15.0 10.6 10.6 10.6
D3 D3 No
0.25 0.25 0.31 65 2.00% 10.2 10.2 9.4 250 0.50% 1.41 2.9 0 0.00%N/A N/A 11.8 11.8 11.8 11.8
D4 D4 No
0.25 0.25 0.31 25 2.00% 6.3 6.3 5.8 250 0.50% 1.41 2.9 0 0.00% N/A N/A 11.5 9.3 9.3 8.8
DEVELOPED TIME OF CONCENTRATION COMPUTATIONS
Gutter Flow Swale Flow
Design
Point Basin
Overland Flow
CLU
November 3, 2021
Time of Concentration
(Equation RO-4)
()
31
*1.187.1
S
LCfCTi
-=
Rational Method Equation:Project:1536-001
Calculations By:
Date:
From Section 3.2.1 of the CFCSDDC
Rainfall Intensity:
A1 A1 2.88
10 10 10 0.25 0.25 0.31 2.21 3.78 7.72 1.59 2.72 6.95 0.80
A2 A2 0.88
7 7 7 0.87 0.87 1.00 2.60 4.44 9.06 1.99 3.41 7.97 1.00
A3 A3 0.31
6 6 6 0.87 0.87 1.00 2.67 4.56 9.63 0.72 1.23 2.99 0.36
A4 A4 0.89
9 9 8 0.87 0.87 1.00 2.35 4.02 8.38 1.83 3.12 7.46 0.91
A5 A5 2.21
12 12 11 0.87 0.87 1.00 2.09 3.57 7.42 4.03 6.88 16.40 2.02
A6 A6 0.96
11 11 10 0.87 0.87 1.00 2.13 3.63 7.72 1.79 3.04 7.41 0.89
A7 A7 1.13
11 11 11 0.87 0.87 1.00 2.13 3.63 7.57 2.10 3.58 8.55 1.05
A8 A8 0.53
12 12 12 0.87 0.87 1.00 2.05 3.50 7.29 0.94 1.60 3.83 0.47
B1 B1 2.41
10 10 10 0.25 0.25 0.31 2.21 3.78 7.72 1.33 2.28 5.81 0.67
B2 B2 3.08
12 12 12 0.67 0.67 0.84 2.05 3.50 7.16 4.24 7.24 18.52 2.12
B3 B3 1.95
12 12 11 0.87 0.87 1.00 2.09 3.57 7.42 3.56 6.07 14.47 1.78
B4 B4 1.07
10 10 10 0.87 0.87 1.00 2.21 3.78 7.72 2.06 3.52 8.26 1.03
B5 B5 1.64
12 12 12 0.87 0.87 1.00 2.09 3.57 7.29 2.99 5.10 11.96 1.50
C1 C1 3.63
10 10 10 0.25 0.25 0.31 2.21 3.78 7.72 2.01 3.43 8.76 1.00
C2 C2 2.18
14 14 14 0.87 0.87 1.00 1.95 3.34 6.82 3.71 6.36 14.86 1.86
C3 C3 1.09
12 12 12 0.87 0.87 1.00 2.05 3.50 7.16 1.94 3.32 7.80 0.97
C4 C4 1.09 5 5 5 0.87 0.87 1.00 2.85 4.87 9.95 2.71 4.63 10.85 1.36
C5 C5 2.32 6 6 5 0.87 0.87 1.00 2.76 4.72 9.95 5.59 9.55 23.08 2.80
C6 C6 2.12 6 6 5 0.87 0.87 1.00 2.76 4.72 9.95 5.12 8.74 21.12 2.56
C7 C7 2.20 11 11 11 0.87 0.87 1.00 2.17 3.71 7.57 4.17 7.12 16.65 2.08
C8 C8 0.70 6 6 6 0.87 0.87 1.00 2.67 4.56 9.63 1.63 2.78 6.74 0.81
D1 D1 2.32 8 8 8 0.61 0.61 0.77 2.40 4.10 8.38 3.42 5.84 14.92 1.71
D2 D2 1.30 11 11 11 0.87 0.87 1.00 2.17 3.71 7.57 2.46 4.21 9.84 1.23
D3 D3 1.68 12 12 12 0.82 0.82 1.00 2.09 3.57 7.29 2.87 4.90 12.25 1.44
D4 D4 0.93 9 9 9 0.87 0.87 1.00 2.30 3.93 8.21 1.87 3.19 7.63 0.93
WQ Flow
(cfs)
DEVELOPED RUNOFF COMPUTATIONS
C100
Design
Point
Flow,
Q100
(cfs)
Flow,
Q2
(cfs)
10-yr
Tc
(min)
2-yr
Tc
(min)
C2
Flow,
Q10
(cfs)
Intensity,
i100
(in/hr)
Basin(s)
CLU
November 3, 2021
Intensity,
i10
(in/hr)
Rainfall Intensity taken from the City of Fort Collins Storm Drainage Design Criteria (CFCSDDC), Figure 3.1
C10
Area, A
(acres)
Intensity,
i2
(in/hr)
100-yr
Tc
(min)
()()()AiCCQf=
FORT COLLINS STORMWATER CRITERIA MANUAL Hydrology Standards (Ch. 5)
3.0 Rational Method
3.2 Runoff Coefficients
Page 4
3.2 Runoff Coefficients
Runoff coefficients used for the Rational Method are determined based on either overall land use or
surface type across the drainage area. For Overall Drainage Plan (ODP) submittals, when surface types
may not yet be known, land use shall be used to estimate flow rates and volumes. Table 3.2-1 lists the
runoff coefficients for common types of land uses in the City.
Table 3.2-1. Zoning Classification - Runoff Coefficients
Land Use Runoff Coefficient (C)
Residential
Urban Estate 0.30
Low Density 0.55
Medium Density 0.65
High Density 0.85
Commercial
Commercial 0.85
Industrial 0.95
Undeveloped
Open Lands, Transition 0.20
Greenbelts, Agriculture 0.20
Reference: For further guidance regarding zoning classifications, refer to the Land Use
Code, Article 4.
For a Project Development Plan (PDP) or Final Plan (FP) submittals, runoff coefficients must be based on
the proposed land surface types. Since the actual runoff coefficients may be different from those
specified in Table 3.2-1, Table 3.2-2 lists coefficients for the specific types of land surfaces.
FORT COLLINS STORMWATER CRITERIA MANUAL Hydrology Standards (Ch. 5)
3.0 Rational Method
3.2 Runoff Coefficients
Page 5
Table 3.2-2. Surface Type - Runoff Coefficients
Surface Type Runoff Coefficients
Hardscape or Hard Surface
Asphalt, Concrete 0.95
Rooftop 0.95
Recycled Asphalt 0.80
Gravel 0.50
Pavers 0.50
Landscape or Pervious Surface
Lawns, Sandy Soil, Flat Slope < 2% 0.10
Lawns, Sandy Soil, Avg Slope 2-7% 0.15
Lawns, Sandy Soil, Steep Slope >7% 0.20
Lawns, Clayey Soil, Flat Slope < 2% 0.20
Lawns, Clayey Soil, Avg Slope 2-7% 0.25
Lawns, Clayey Soil, Steep Slope >7% 0.35
3.2.1 Composite Runoff Coefficients
Drainage sub-basins are frequently composed of land that has multiple surface types or zoning
classifications. In such cases a composite runoff coefficient must be calculated for any given drainage
sub-basin.
The composite runoff coefficient is obtained using the following formula:
( )
t
n
i
ii
A
xAC
C
∑
==1 Equation 5-2
Where: C = Composite Runoff Coefficient
Ci = Runoff Coefficient for Specific Area (Ai), dimensionless
Ai = Area of Surface with Runoff Coefficient of Ci, acres or square feet
n = Number of different surfaces to be considered
At = Total Area over which C is applicable, acres or square feet
3.2.2 Runoff Coefficient Frequency Adjustment Factor
The runoff coefficients provided in Table 3.2-1 and Table 3.2-2 are appropriate for use with the 2-year
storm event. For any analysis of storms with higher intensities, an adjustment of the runoff coefficient is
required due to the lessening amount of infiltration, depression retention, evapotranspiration and other
losses that have a proportionally smaller effect on high-intensity storm runoff. This adjustment is
FORT COLLINS STORMWATER CRITERIA MANUAL Hydrology Standards (Ch. 5)
3.0 Rational Method
3.3 Time of Concentration
Page 6
applied to the composite runoff coefficient. These frequency adjustment factors, Cf, are found in Table
3.2-3.
Table 3.2-3. Frequency Adjustment Factors
Storm Return Period
(years)
Frequency Adjustment
Factor (Cf)
2, 5, 10 1.00
25 1.10
50 1.20
100 1.25
3.3 Time of Concentration
3.3.1 Overall Equation
The next step to approximate runoff using the Rational Method is to estimate the Time of
Concentration, Tc, or the time for water to flow from the most remote part of the drainage sub-basin to
the design point under consideration.
The Time of Concentration is represented by the following equation:
𝐓𝐓𝐜𝐜=𝐓𝐓𝐢𝐢+𝐓𝐓𝐭𝐭 Equation 5-3
Where: Tc = Total Time of Concentration, minutes
Ti = Initial or Overland Flow Time of Concentration, minutes
Tt = Channelized Flow in Swale, Gutter or Pipe, minutes
3.3.2 Overland Flow Time
Overland flow, Ti, can be determined by the following equation:
𝐓𝐓𝐢𝐢=𝟏𝟏.𝟖𝟖𝟖𝟖(𝟏𝟏.𝟏𝟏−𝐂𝐂𝐂𝐂𝐂𝐂𝐟𝐟)√𝐋𝐋√𝐒𝐒𝟑𝟑 Equation 3.3-2
Where: C = Runoff Coefficient, dimensionless
Cf = Frequency Adjustment Factor, dimensionless
L = Length of Overland Flow, feet
S = Slope, percent
CXCF
PRODUCT OF CXCF
CANNOT EXCEED THE
VALUE OF 1
OVERLAND FLOW LENGTH
L=200’ MAX IN DEVELOPED AREAS
L=500’ MAX IN UNDEVELOPED
AREAS
FORT COLLINS STORMWATER CRITERIA MANUAL Hydrology Standards (Ch. 5)
3.0 Rational Method
3.4 Intensity-Duration-Frequency Curves for Rational Method
Page 7
3.3.3 Channelized Flow Time
Travel time in a swale, gutter or storm pipe is considered “channelized” or “concentrated” flow and can
be estimated using the Manning’s Equation:
𝐕𝐕= 𝟏𝟏.𝟒𝟒𝟒𝟒𝐧𝐧 𝐑𝐑𝟐𝟐/𝟑𝟑𝐒𝐒𝟏𝟏/𝟐𝟐 Equation 5-4
Where: V = Velocity, feet/second
n = Roughness Coefficient, dimensionless
R = Hydraulic Radius, feet (Hydraulic Radius = area / wetted perimeter, feet)
S = Longitudinal Slope, feet/feet
And:
𝐓𝐓𝐭𝐭=𝐋𝐋𝐕𝐕𝐂𝐂𝐕𝐕𝐕𝐕 Equation 5-5
3.3.4 Total Time of Concentration
A minimum Tc of 5 minutes is required. The maximum Tc
allowed for the most upstream design point shall be
calculated using the following equation:
𝐓𝐓𝐜𝐜=𝐋𝐋𝟏𝟏𝟖𝟖𝐕𝐕+𝟏𝟏𝐕𝐕 Equation 3.3-5
The Total Time of Concentration, Tc, is the lesser of the
values of Tc calculated using Tc = Ti + Tt or the equation
listed above.
3.4 Intensity-Duration-Frequency Curves for Rational Method
The two-hour rainfall Intensity-Duration-Frequency curves for use with the Rational Method is provided
in Table 3.4-1 and Figure 3.4-1.
TC
• A MINIMUM TC OF 5
MINUTES IS REQUIRED IN
ALL CASES.
• A MAXIMUM TC OF 5
MINUTES IS TYPICAL FOR
SMALLER, URBAN PROJECTS.
FORT COLLINS STORMWATER CRITERIA MANUAL Hydrology Standards (Ch. 5)
3.0 Rational Method
3.4 Intensity-Duration-Frequency Curves for Rational Method
Page 8
Table 3.4-1. IDF Table for Rational Method
Duration
(min)
Intensity
2-year
(in/hr)
Intensity
10-year
(in/hr)
Intensity
100-year
(in/hr)
Duration
(min)
Intensity
2-year
(in/hr)
Intensity
10-year
(in/hr)
Intensity
100-year
(in/hr)
5 2.85 4.87 9.95
39 1.09 1.86 3.8
6 2.67 4.56 9.31
40 1.07 1.83 3.74
7 2.52 4.31 8.80
41 1.05 1.80 3.68
8 2.40 4.10 8.38
42 1.04 1.77 3.62
9 2.30 3.93 8.03
43 1.02 1.74 3.56
10 2.21 3.78 7.72
44 1.01 1.72 3.51
11 2.13 3.63 7.42
45 0.99 1.69 3.46
12 2.05 3.50 7.16
46 0.98 1.67 3.41
13 1.98 3.39 6.92
47 0.96 1.64 3.36
14 1.92 3.29 6.71
48 0.95 1.62 3.31
15 1.87 3.19 6.52
49 0.94 1.6 3.27
16 1.81 3.08 6.30
50 0.92 1.58 3.23
17 1.75 2.99 6.10
51 0.91 1.56 3.18
18 1.70 2.90 5.92
52 0.9 1.54 3.14
19 1.65 2.82 5.75
53 0.89 1.52 3.10
20 1.61 2.74 5.60
54 0.88 1.50 3.07
21 1.56 2.67 5.46
55 0.87 1.48 3.03
22 1.53 2.61 5.32
56 0.86 1.47 2.99
23 1.49 2.55 5.20
57 0.85 1.45 2.96
24 1.46 2.49 5.09
58 0.84 1.43 2.92
25 1.43 2.44 4.98
59 0.83 1.42 2.89
26 1.4 2.39 4.87
60 0.82 1.4 2.86
27 1.37 2.34 4.78
65 0.78 1.32 2.71
28 1.34 2.29 4.69
70 0.73 1.25 2.59
29 1.32 2.25 4.60
75 0.70 1.19 2.48
30 1.30 2.21 4.52
80 0.66 1.14 2.38
31 1.27 2.16 4.42
85 0.64 1.09 2.29
32 1.24 2.12 4.33
90 0.61 1.05 2.21
33 1.22 2.08 4.24
95 0.58 1.01 2.13
34 1.19 2.04 4.16
100 0.56 0.97 2.06
35 1.17 2.00 4.08
105 0.54 0.94 2.00
36 1.15 1.96 4.01
110 0.52 0.91 1.94
37 1.16 1.93 3.93
115 0.51 0.88 1.88
38 1.11 1.89 3.87
120 0.49 0.86 1.84
FORT COLLINS STORMWATER CRITERIA MANUAL Hydrology Standards (Ch. 5)
3.0 Rational Method
3.4 Intensity-Duration-Frequency Curves for Rational Method
Page 9
Figure 3.4-1. Rainfall IDF Curve – Fort Collins
APPENDIX B
USDA Soils Information
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
February 1, 2019
Preface
Soil surveys contain information that affects land use planning in survey areas.
They highlight soil limitations that affect various land uses and provide information
about the properties of the soils in the survey areas. Soil surveys are designed for
many different users, including farmers, ranchers, foresters, agronomists, urban
planners, community officials, engineers, developers, builders, and home buyers.
Also, conservationists, teachers, students, and specialists in recreation, waste
disposal, and pollution control can use the surveys to help them understand,
protect, or enhance the environment.
Various land use regulations of Federal, State, and local governments may impose
special restrictions on land use or land treatment. Soil surveys identify soil
properties that are used in making various land use or land treatment decisions.
The information is intended to help the land users identify and reduce the effects of
soil limitations on various land uses. The landowner or user is responsible for
identifying and complying with existing laws and regulations.
Although soil survey information can be used for general farm, local, and wider area
planning, onsite investigation is needed to supplement this information in some
cases. Examples include soil quality assessments (http://www.nrcs.usda.gov/wps/
portal/nrcs/main/soils/health/) and certain conservation and engineering
applications. For more detailed information, contact your local USDA Service Center
(https://offices.sc.egov.usda.gov/locator/app?agency=nrcs) or your NRCS State Soil
Scientist (http://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/contactus/?
cid=nrcs142p2_053951).
Great differences in soil properties can occur within short distances. Some soils are
seasonally wet or subject to flooding. Some are too unstable to be used as a
foundation for buildings or roads. Clayey or wet soils are poorly suited to use as
septic tank absorption fields. A high water table makes a soil poorly suited to
basements or underground installations.
The National Cooperative Soil Survey is a joint effort of the United States
Department of Agriculture and other Federal agencies, State agencies including the
Agricultural Experiment Stations, and local agencies. The Natural Resources
Conservation Service (NRCS) has leadership for the Federal part of the National
Cooperative Soil Survey.
Information about soils is updated periodically. Updated information is available
through the NRCS Web Soil Survey, the site for official soil survey information.
The U.S. Department of Agriculture (USDA) prohibits discrimination in all its
programs and activities on the basis of race, color, national origin, age, disability,
and where applicable, sex, marital status, familial status, parental status, religion,
sexual orientation, genetic information, political beliefs, reprisal, or because all or a
part of an individual's income is derived from any public assistance program. (Not
all prohibited bases apply to all programs.) Persons with disabilities who require
2
alternative means for communication of program information (Braille, large print,
audiotape, etc.) should contact USDA's TARGET Center at (202) 720-2600 (voice
and TDD). To file a complaint of discrimination, write to USDA, Director, Office of
Civil Rights, 1400 Independence Avenue, S.W., Washington, D.C. 20250-9410 or
call (800) 795-3272 (voice) or (202) 720-6382 (TDD). USDA is an equal opportunity
provider and employer.
3
Contents
Preface....................................................................................................................2
How Soil Surveys Are Made..................................................................................5
Soil Map..................................................................................................................8
Soil Map................................................................................................................9
Legend................................................................................................................10
Map Unit Legend................................................................................................11
Map Unit Descriptions.........................................................................................11
Larimer County Area, Colorado......................................................................13
4—Altvan-Satanta loams, 3 to 9 percent slopes.........................................13
36—Fort Collins loam, 3 to 5 percent slopes..............................................15
63—Longmont clay, 0 to 3 percent slopes..................................................16
74—Nunn clay loam, 1 to 3 percent slopes.................................................17
76—Nunn clay loam, wet, 1 to 3 percent slopes.........................................19
105—Table Mountain loam, 0 to 1 percent slopes......................................20
References............................................................................................................22
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
449310044932004493300449340044935004493600449310044932004493300449340044935004493600489400 489500 489600 489700 489800 489900 490000 490100 490200 490300
489400 489500 489600 489700 489800 489900 490000 490100 490200 490300
40° 35' 38'' N 105° 7' 31'' W40° 35' 38'' N105° 6' 50'' W40° 35' 18'' N
105° 7' 31'' W40° 35' 18'' N
105° 6' 50'' WN
Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 13N WGS84
0 200 400 800 1200
Feet
0 50 100 200 300
Meters
Map Scale: 1:4,400 if printed on A landscape (11" x 8.5") sheet.
Soil Map may not be valid at this scale.
MAP LEGEND MAP INFORMATION
Area of Interest (AOI)
Area of Interest (AOI)
Soils
Soil Map Unit Polygons
Soil Map Unit Lines
Soil Map Unit Points
Special Point Features
Blowout
Borrow Pit
Clay Spot
Closed Depression
Gravel Pit
Gravelly Spot
Landfill
Lava Flow
Marsh or swamp
Mine or Quarry
Miscellaneous Water
Perennial Water
Rock Outcrop
Saline Spot
Sandy Spot
Severely Eroded Spot
Sinkhole
Slide or Slip
Sodic Spot
Spoil Area
Stony Spot
Very Stony Spot
Wet Spot
Other
Special Line Features
Water Features
Streams and Canals
Transportation
Rails
Interstate Highways
US Routes
Major Roads
Local Roads
Background
Aerial Photography
The soil surveys that comprise your AOI were mapped at
1:24,000.
Warning: Soil Map may not be valid at this scale.
Enlargement of maps beyond the scale of mapping can cause
misunderstanding of the detail of mapping and accuracy of soil
line placement. The maps do not show the small areas of
contrasting soils that could have been shown at a more detailed
scale.
Please rely on the bar scale on each map sheet for map
measurements.
Source of Map: Natural Resources Conservation Service
Web Soil Survey URL:
Coordinate System: Web Mercator (EPSG:3857)
Maps from the Web Soil Survey are based on the Web Mercator
projection, which preserves direction and shape but distorts
distance and area. A projection that preserves area, such as the
Albers equal-area conic projection, should be used if more
accurate calculations of distance or area are required.
This product is generated from the USDA-NRCS certified data as
of the version date(s) listed below.
Soil Survey Area: Larimer County Area, Colorado
Survey Area Data: Version 13, Sep 10, 2018
Soil map units are labeled (as space allows) for map scales
1:50,000 or larger.
Date(s) aerial images were photographed: Sep 20, 2015—Oct
21, 2017
The orthophoto or other base map on which the soil lines were
compiled and digitized probably differs from the background
imagery displayed on these maps. As a result, some minor
shifting of map unit boundaries may be evident.
Custom Soil Resource Report
10
Map Unit Legend
Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI
4 Altvan-Satanta loams, 3 to 9
percent slopes
8.7 14.8%
36 Fort Collins loam, 3 to 5 percent
slopes
2.7 4.5%
63 Longmont clay, 0 to 3 percent
slopes
3.9 6.7%
74 Nunn clay loam, 1 to 3 percent
slopes
4.3 7.2%
76 Nunn clay loam, wet, 1 to 3
percent slopes
36.0 60.9%
105 Table Mountain loam, 0 to 1
percent slopes
3.5 6.0%
Totals for Area of Interest 59.2 100.0%
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
Custom Soil Resource Report
11
was impractical to make enough observations to identify all the soils and
miscellaneous areas on the landscape.
The presence of minor components in a map unit in no way diminishes the
usefulness or accuracy of the data. The objective of mapping is not to delineate
pure taxonomic classes but rather to separate the landscape into landforms or
landform segments that have similar use and management requirements. The
delineation of such segments on the map provides sufficient information for the
development of resource plans. If intensive use of small areas is planned, however,
onsite investigation is needed to define and locate the soils and miscellaneous
areas.
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.
Custom Soil Resource Report
12
Larimer County Area, Colorado
4—Altvan-Satanta loams, 3 to 9 percent slopes
Map Unit Setting
National map unit symbol: jpwf
Elevation: 5,200 to 6,200 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: Farmland of statewide importance
Map Unit Composition
Altvan and similar soils: 55 percent
Satanta and similar soils: 35 percent
Minor components: 10 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
Description of Altvan
Setting
Landform: Fans, benches, terraces
Landform position (three-dimensional): Base slope, side slope, tread
Down-slope shape: Linear
Across-slope shape: Linear
Parent material: Mixed alluvium
Typical profile
H1 - 0 to 9 inches: loam
H2 - 9 to 16 inches: clay loam, loam, sandy clay loam
H2 - 9 to 16 inches: loam, fine sandy loam, silt loam
H2 - 9 to 16 inches: gravelly sand, gravelly coarse sand, coarse sand
H3 - 16 to 31 inches:
H3 - 16 to 31 inches:
H3 - 16 to 31 inches:
H4 - 31 to 60 inches:
H4 - 31 to 60 inches:
H4 - 31 to 60 inches:
Properties and qualities
Slope: 6 to 9 percent
Depth to restrictive feature: More than 80 inches
Natural drainage class: Well drained
Runoff class: Medium
Capacity of the most limiting layer to transmit water (Ksat): Moderately high to
high (0.60 to 2.00 in/hr)
Depth to water table: More than 80 inches
Frequency of flooding: None
Frequency of ponding: None
Calcium carbonate, maximum in profile: 10 percent
Available water storage in profile: Very high (about 13.7 inches)
Interpretive groups
Land capability classification (irrigated): 4e
Land capability classification (nonirrigated): 4e
Custom Soil Resource Report
13
Hydrologic Soil Group: B
Hydric soil rating: No
Description of Satanta
Setting
Landform: Terraces, structural benches
Landform position (three-dimensional): Side slope, tread
Down-slope shape: Linear
Across-slope shape: Linear
Parent material: Mixed alluvium and/or eolian deposits
Typical profile
H1 - 0 to 9 inches: loam
H2 - 9 to 14 inches: loam, clay loam, sandy clay loam
H2 - 9 to 14 inches: loam, clay loam, fine sandy loam
H2 - 9 to 14 inches:
H3 - 14 to 60 inches:
H3 - 14 to 60 inches:
H3 - 14 to 60 inches:
Properties and qualities
Slope: 3 to 6 percent
Depth to restrictive feature: More than 80 inches
Natural drainage class: Well drained
Runoff class: Medium
Capacity of the most limiting layer to transmit water (Ksat): Moderately high to
high (0.60 to 2.00 in/hr)
Depth to water table: More than 80 inches
Frequency of flooding: None
Frequency of ponding: None
Calcium carbonate, maximum in profile: 10 percent
Available water storage in profile: Very high (about 27.4 inches)
Interpretive groups
Land capability classification (irrigated): 2e
Land capability classification (nonirrigated): 3e
Hydrologic Soil Group: B
Hydric soil rating: No
Minor Components
Nunn
Percent of map unit: 6 percent
Hydric soil rating: No
Larimer
Percent of map unit: 4 percent
Hydric soil rating: No
Custom Soil Resource Report
14
36—Fort Collins loam, 3 to 5 percent slopes
Map Unit Setting
National map unit symbol: jpw9
Elevation: 4,800 to 5,500 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: 90 percent
Minor components: 10 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
Description of Fort Collins
Setting
Landform: Fans, terraces
Landform position (three-dimensional): Base slope, riser
Down-slope shape: Linear
Across-slope shape: Linear
Parent material: Alluvium
Typical profile
H1 - 0 to 9 inches: loam
H2 - 9 to 20 inches: loam, clay loam
H2 - 9 to 20 inches: loam, silt loam, fine sandy loam
H3 - 20 to 60 inches:
H3 - 20 to 60 inches:
H3 - 20 to 60 inches:
Properties and qualities
Slope: 3 to 5 percent
Depth to restrictive feature: More than 80 inches
Natural drainage class: Well drained
Runoff class: Low
Capacity of the most limiting layer to transmit water (Ksat): Moderately high to
high (0.60 to 2.00 in/hr)
Depth to water table: More than 80 inches
Frequency of flooding: None
Frequency of ponding: None
Calcium carbonate, maximum in profile: 15 percent
Salinity, maximum in profile: Nonsaline to very slightly saline (0.0 to 2.0
mmhos/cm)
Available water storage in profile: Very high (about 25.5 inches)
Interpretive groups
Land capability classification (irrigated): 3e
Custom Soil Resource Report
15
Land capability classification (nonirrigated): 3e
Hydrologic Soil Group: B
Ecological site: Loamy Plains (R067XY002CO)
Hydric soil rating: No
Minor Components
Ascalon
Percent of map unit: 5 percent
Hydric soil rating: No
Kim
Percent of map unit: 3 percent
Hydric soil rating: No
Stoneham
Percent of map unit: 2 percent
Hydric soil rating: No
63—Longmont clay, 0 to 3 percent slopes
Map Unit Setting
National map unit symbol: jpx8
Elevation: 4,800 to 5,800 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 and reclaimed of excess salts
and sodium
Map Unit Composition
Longmont and similar soils: 85 percent
Minor components: 15 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
Description of Longmont
Setting
Landform: Flood plains, valleys
Landform position (three-dimensional): Base slope, tread
Down-slope shape: Linear
Across-slope shape: Linear
Parent material: Clayey alluvium derived from shale
Typical profile
H1 - 0 to 60 inches: clay
Properties and qualities
Slope: 0 to 3 percent
Depth to restrictive feature: More than 80 inches
Natural drainage class: Poorly drained
Runoff class: High
Custom Soil Resource Report
16
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 30 inches
Frequency of flooding: Occasional
Frequency of ponding: None
Calcium carbonate, maximum in profile: 15 percent
Gypsum, maximum in profile: 5 percent
Salinity, maximum in profile: Slightly saline to strongly saline (4.0 to 16.0
mmhos/cm)
Sodium adsorption ratio, maximum in profile: 20.0
Available water storage in profile: Moderate (about 8.4 inches)
Interpretive groups
Land capability classification (irrigated): None specified
Land capability classification (nonirrigated): 6w
Hydrologic Soil Group: D
Ecological site: Salt Meadow (R067BY035CO)
Hydric soil rating: No
Minor Components
Aquolls
Percent of map unit: 5 percent
Landform: Swales
Hydric soil rating: Yes
Dacono
Percent of map unit: 5 percent
Hydric soil rating: No
Heldt
Percent of map unit: 5 percent
Hydric soil rating: No
74—Nunn clay loam, 1 to 3 percent slopes
Map Unit Setting
National map unit symbol: 2tlpl
Elevation: 3,900 to 5,840 feet
Mean annual precipitation: 13 to 17 inches
Mean annual air temperature: 50 to 54 degrees F
Frost-free period: 135 to 160 days
Farmland classification: Prime farmland if irrigated
Map Unit Composition
Nunn and similar soils: 85 percent
Minor components: 15 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
Custom Soil Resource Report
17
Description of Nunn
Setting
Landform: Terraces
Landform position (three-dimensional): Tread
Down-slope shape: Linear
Across-slope shape: Linear
Parent material: Pleistocene aged alluvium and/or eolian deposits
Typical profile
Ap - 0 to 9 inches: clay loam
Bt - 9 to 13 inches: clay loam
Btk - 13 to 25 inches: clay loam
Bk1 - 25 to 38 inches: clay loam
Bk2 - 38 to 80 inches: clay loam
Properties and qualities
Slope: 1 to 3 percent
Depth to restrictive feature: More than 80 inches
Natural drainage class: Well drained
Runoff class: Medium
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: More than 80 inches
Frequency of flooding: None
Frequency of ponding: None
Calcium carbonate, maximum in profile: 7 percent
Salinity, maximum in profile: Nonsaline to very slightly saline (0.1 to 2.0
mmhos/cm)
Sodium adsorption ratio, maximum in profile: 0.5
Available water storage in profile: High (about 9.9 inches)
Interpretive groups
Land capability classification (irrigated): 2e
Land capability classification (nonirrigated): 3e
Hydrologic Soil Group: C
Ecological site: Clayey Plains (R067BY042CO)
Hydric soil rating: No
Minor Components
Heldt
Percent of map unit: 10 percent
Landform: Terraces
Landform position (three-dimensional): Tread
Down-slope shape: Linear
Across-slope shape: Linear
Ecological site: Clayey Plains (R067BY042CO)
Hydric soil rating: No
Satanta
Percent of map unit: 5 percent
Landform: Terraces
Landform position (three-dimensional): Tread
Down-slope shape: Linear
Across-slope shape: Linear
Custom Soil Resource Report
18
Ecological site: Loamy Plains (R067BY002CO)
Hydric soil rating: No
76—Nunn clay loam, wet, 1 to 3 percent slopes
Map Unit Setting
National map unit symbol: jpxq
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
Nunn, wet, and similar soils: 90 percent
Minor components: 10 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
Description of Nunn, Wet
Setting
Landform: Alluvial fans, stream terraces
Landform position (three-dimensional): Base slope, tread
Down-slope shape: Linear
Across-slope shape: Linear
Parent material: Alluvium
Typical profile
H1 - 0 to 10 inches: clay loam
H2 - 10 to 47 inches: clay loam, clay
H2 - 10 to 47 inches: clay loam, loam, gravelly sandy loam
H3 - 47 to 60 inches:
H3 - 47 to 60 inches:
H3 - 47 to 60 inches:
Properties and qualities
Slope: 1 to 3 percent
Depth to restrictive feature: More than 80 inches
Natural drainage class: Somewhat poorly drained
Runoff class: Medium
Capacity of the most limiting layer to transmit water (Ksat): Moderately low to
moderately high (0.06 to 0.60 in/hr)
Depth to water table: About 24 to 36 inches
Frequency of flooding: Rare
Frequency of ponding: None
Calcium carbonate, maximum in profile: 10 percent
Salinity, maximum in profile: Nonsaline to very slightly saline (0.0 to 2.0
mmhos/cm)
Available water storage in profile: Very high (about 19.8 inches)
Custom Soil Resource Report
19
Interpretive groups
Land capability classification (irrigated): 2w
Land capability classification (nonirrigated): 3s
Hydrologic Soil Group: C
Hydric soil rating: No
Minor Components
Heldt
Percent of map unit: 6 percent
Hydric soil rating: No
Dacono
Percent of map unit: 3 percent
Hydric soil rating: No
Mollic halaquepts
Percent of map unit: 1 percent
Landform: Swales
Hydric soil rating: Yes
105—Table Mountain loam, 0 to 1 percent slopes
Map Unit Setting
National map unit symbol: jpty
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
Table mountain and similar soils: 85 percent
Minor components: 15 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
Description of Table Mountain
Setting
Landform: Flood plains, stream terraces
Landform position (three-dimensional): Tread
Down-slope shape: Linear
Across-slope shape: Linear
Parent material: Alluvium
Typical profile
H1 - 0 to 36 inches: loam
H2 - 36 to 60 inches: loam, clay loam, silt loam
H2 - 36 to 60 inches:
H2 - 36 to 60 inches:
Custom Soil Resource Report
20
Properties and qualities
Slope: 0 to 1 percent
Depth to restrictive feature: More than 80 inches
Natural drainage class: Well drained
Runoff class: Low
Capacity of the most limiting layer to transmit water (Ksat): Moderately high to
high (0.60 to 2.00 in/hr)
Depth to water table: More than 80 inches
Frequency of flooding: None
Frequency of ponding: None
Calcium carbonate, maximum in profile: 15 percent
Salinity, maximum in profile: Nonsaline to very slightly saline (0.0 to 2.0
mmhos/cm)
Sodium adsorption ratio, maximum in profile: 5.0
Available water storage in profile: Very high (about 18.0 inches)
Interpretive groups
Land capability classification (irrigated): 1
Land capability classification (nonirrigated): 3c
Hydrologic Soil Group: B
Ecological site: Overflow (R049XY036CO)
Hydric soil rating: No
Minor Components
Caruso
Percent of map unit: 7 percent
Hydric soil rating: No
Fluvaquentic haplustolls
Percent of map unit: 4 percent
Landform: Terraces
Hydric soil rating: Yes
Paoli
Percent of map unit: 4 percent
Hydric soil rating: No
Custom Soil Resource Report
21
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
22
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
23
APPENDIX C
Water Quality Calculations, LID Information
ST STSTST ST
ST
ST
ST
ST
STSTV.P.
V.P.FE
SB M
D
FES
V.P.V.P.V.P.V.P.V.P.
V.P.
CONTROLIRR
CONTROLIRRCONTROLIRR
CONTROLIRR
CONTROLIRR
CONTROLIRR CONTROLIRR
CONTROLIRR
CONTROLIRR CONTROLIRR
CONTROLIRR
CONTROLIRR
CONTROLIRR
TESTSTA
V.P.
CONTROLIRRCONTROLIRR
CONTROLIRR
V.P.
V.P.V.P.
V.P.
MW
MW
MW
F ESFES
MW
TH
TH
TSALPOLYND
D DONOTPOLLTEUCTILEIRONRAINSTOWATERWAYSUTSALPOLYNDDDONOTPOLLTEUCTILEIRONRAINSTOWATERWAYSU
TSALPOLYNDDDONOTPOLLTEUCTILEIRONRAINSTOWATERWAYS
U
TSALPOLYND
D D
ONOTPOLLTEUCTILEIRONRAINSTOWATERWAYSU
TSALPOLYNDDDONOTPOLLTEUCTILEIRONRAINSTOWATERWAYSU
TSALPOLYND
D D
ONOTPOLLTEUCTILEIRONRAINSTOWATERWAYSU
TSALPOLYNDDDONOTPOLLTEUCTILEIRONRAINSTOWATERWAYSU
TSALPOLYND
D D
ONOTPOLLTEUCTILEIRONRAINSTOWATERWAYSU
TSALPOLYND
DDONOTPOLLTEUCTILEIRONRAINSTOWATERWAYSU
TSALPOLYND
DDONOTPOLLTEUCTILEIRONRAINSTOWATERWAYSU
TSALPOLYND
DD
ONOTPOLLTEUCTILEIRONRAINSTOWATERWAYSU TSALPOLYND
DDONOTPOLLTEUCTILEIRONRAINSTOWATERWAYSU
TSALPOLYND
DDONOTPOLLTEUCTILEIRONRAINSTOWATERWAYSU
TSALPOLYNDDDONOTPOLLTEUCTILEIRONRAINSTOWATERWAYSU
TSALPOLYND
D DONOTPOLLTEUCTILEIRONRAINSTOWATERWAYSU
TSALPOLYND
D DONOTPOLLTEUCTILEIRONRAINSTOWATERWAYSU EEEEEEEEEE
EEEE
EEE
EE
EEE
SBSBSB
SB
SBSB SB
SB
SB
SB
SB
SB
SBSB
SBEE EEEEEEEEEEEEEEEEEEEEEEEEEEE
E EEEE
EEE EEEE
EEEEE
EEE
TSALPOLYND
D DONOTPOLLTEUCTILEIRONRAINSTOWATERWAYSU
TSALPOLYND
DDONOTPOLLTEUCTILEIRONRAINSTOWATERWAYSU
TSALPOLYND
D D
ONOTPOLLTEUCTILEIRONRAINSTOWATERWAYSU
TSALPOLYND
DDONOTPOLLTEUCTILEIRONRAINSTOWATERWAYSU
TSALPOLYND
D DONOTPOLLTEUCTILEIRONRAINSTOWATERWAYSU
TSALPOLYNDDDONOTPOLLTEUCTILEIRONRAINSTOWATERWAYS
U
NYLOPLAST
DO NOT POLLUTE DRAINS TO WATERWAYS
E
E
EETSALPOLYND
D D
ONOTPOLLTEUCTILEIRONRAINSTOWATERWAYSU
TSALPOLYNDDDONOTPOLLTEUCTILEIRONRAINSTOWATERWAYSU
STORMTECH
CHAMBERS A6
STORMTECH
CHAMBERS B3
5' GRAVEL
BIORETENTION
DETENTION
POND 3
DETENTION
POND 2
DETENTION
POND 1
DETENTION
POND 4
DETENTION
POND 5
STORM TECH
CHAMBERS C2
RAIN GARDEN D5
RAIN
GARDEN B2
RAIN
GARDEN B5
RAIN
GARDEN C5
RAIN
GARDEN B4
1.13 ac.
A-7
0.89 ac.
A-4
3.08 ac.
B-2
1.09 ac.
C-4
3.63 ac.
C-1
0.52 ac.
A-8
2.88 ac.
A-1
1.07 ac.
B-4
2.21 ac.
A-5
0.31 ac.
A-3
2.41 ac.
B-1
1.95 ac.
B-3
0.93 ac.
D-4
2.18 ac.
C-2
2.32 ac.
C-5
2.20 ac.
C-72.32 ac.
D-1
1.30 ac.
D-2
1.68 ac.
D-3
0.96 ac.
A-6
0.88 ac.
A-2
1.09 ac.
C-3
2.12 ac.
C-6
1.64 ac.
B-5
0.70 ac.
C-8
STORMTECH
CHAMBERS A5
5' GRAVEL
BIORETENTION
5' GRAVEL
BIORETENTION
RAIN
GARDEN C6
RAIN
GARDEN D3
( IN FEET )
1 inch = ft.
Feet0120120
120
240 360
E N G I N E E R N GI
EHTRON R N PRELIMINARY LID EXHIBIT
NOVEMBER 3, 2021 FORT COLLINS, CO
SANCTUARY ON THE GREEN
LID Summary per Basin
Basin ID Area Percent
Impervious LID ID Treatment Type Required
Volume (ft3)
Total Impervious
Area (ft2)Sq. Ft.Acres
A-1 125,652 2.88 0%n/a n/a 0 0
A-2 38,332 0.88 85%n/a n/a 0 32,582
A-3 13,504 0.31 85%n/a n/a 0 11,478
A-4 38,618 0.89 85%n/a n/a 0 32,825
A-5 96,267 2.21 85%LID A5 Storm Tech 2,789 81,827
A-6 41,817 0.96 85%LID A6 Storm Tech 1,211 35,544
A-7 49,222 1.13 85%n/a n/a 0 41,839
A-8 22,651 0.52 85%n/a n/a 0 19,253
B-1 105,093 2.41 0%n/a n/a 0 0
B-2 134,165 3.08 85%LID B2 Rain Garden 3,887 114,040
B-3 84,918 1.95 85%LID B3 Storm Tech 2,460 72,180
B-4 40,380 0.93 0%LID B4 Storm Tech 2,460 0
B-5 73,190 1.68 85%LID B5 Rain Garden 2,120 62,212
C-1 158,122 3.63 20%n/a n/a 0 31,624
C-2 94,960 2.18 85%LID C2 Storm Tech 5,501 80,716
C-3 47,480 1.09 85%LID C2 Storm Tech 5,501 40,358
C-4 47,480 1.09 85%LID C2 Storm Tech 5,501 40,358
C-5 101,059 2.32 85%LID C5 Rain Garden 2,927 85,900
C-6 92,347 2.12 85%LID C7 Rain Garden 2,675 78,495
C-7 95,832 2.20 85%n/a n/a 0 81,457
C-8 30,492 0.70 85%LID C8 Gravel Bioretention 883 25,918
D-1 100,956 2.32 48%n/a n/a 0 48,459
D-2 56,634 1.30 85%LID D2 Rain Garden 1,639 48,139
D-3 73,190 1.68 85%LID D3 Rain Garden 2,120 62,212
D-4 40,380 0.93 85%LID D4 Rain Garden 1,170 34,323
Total 1,802,741 41.39 42,844 1,161,741
LID ID
Area Weighted %
Impervious Subbasin ID Treatment Type Volume per UD-BMP
(ft3)
Vol. w/20% Increase
per Fort Collins
Manual (ft3)
Impervious Area
(ft2)
Sq. Ft.Acres
LID A5 96,267 2.21 85%A5 Storm Tech 2,324 2,789 81,827
LID A6 41,817 0.96 85%A6 Storm Tech 1,009 1,211 35,544
LID B2 134,165 3.08 85%B2 Rain Garden 3,239 3,887 114,040
LID B3 84,918 1.95 85%B3 Storm Tech 2,050 2,460 72,180
LID B5 73,190 1.68 85%B5 Rain Garden 1,767 2,120 62,212
LID C2 189,920 4.36 85%C2,3,4 Storm Tech 4,584 5,501 161,432
LID C5 101,059 2.32 85%C5 Rain Garden 2,439 2,927 85,900
LID C6 92,347 2.12 85%C6 Rain Garden 2,229 2,675 78,495
LID C8 30,492 0.70 85%C8 Gravel Bioretention 736 883 25,918
LID D2 56,634 1.30 85%D2 Rain Garden 1,366 1,639 48,139
LID D3 73,190 1.68 85%D3 Rain Garden 1,767 2,120 62,212
LID D4 40,380 0.93 85%D4 Rain Garden 975 1,170 34,323
Total 877,732 20.15 29,382 862,223
LID Site Summary
Total Site Area 1,802,741 ft2
Total Impervious Area 1,161,741 ft2
Total Impervious Area without LID Treatment 299,519 ft2
A1, A2, A3, A4, A5, A7, A8, B1, C1, C7, D1
Total Net Proposed Impervious Area 862,223 ft2
50% Requried Minium Area to be Treated 580,871 ft2
75% Requried Minium Area to be Treated 871,306
Total Treated Area 862,223 ft2
Percent Impervious Treated by LID 74%
Project Number:Project:
Project Location:
Calculations By:Date:
Sq. Ft. Acres
A-1 125,652 2.88 0% n/a n/a 0 0
A-2 38,332 0.88 85% n/a n/a 0 32,582
A-3 13,504 0.31 85% n/a n/a 0 11,478
A-4 38,618 0.89 85% n/a n/a 0 32,825
A-5 96,267 2.21 85% LID A5 Storm Tech 2,789 81,827
A-6 41,817 0.96 85% LID A6 Storm Tech 1,211 35,544
A-7 49,222 1.13 85% n/a n/a 0 41,839
A-8 22,651 0.52 85% n/a n/a 0 19,253
B-1 105,093 2.41 0% n/a n/a 0 0
B-2 134,165 3.08 85% LID B2 Rain Garden 3,887 114,040
B-3 84,918 1.95 85% LID B3 Storm Tech 2,460 72,180
B-4 40,380 0.93 0% LID B4 Storm Tech 2,460 0
B-5 73,190 1.68 85% LID B5 Rain Garden 2,120 62,212
C-1 158,122 3.63 20% n/a n/a 0 31,624
C-2 94,960 2.18 85% LID C2 Storm Tech 5,501 80,716
C-3 47,480 1.09 85% LID C2 Storm Tech 5,501 40,358
C-4 47,480 1.09 85% LID C2 Storm Tech 5,501 40,358
C-5 101,059 2.32 85% LID C5 Rain Garden 2,927 85,900
C-6 92,347 2.12 85% LID C7 Rain Garden 2,675 78,495
C-7 95,832 2.20 85% n/a n/a 0 81,457
C-8 30,492 0.70 85% LID C8 Gravel Bioretention 883 25,918
D-1 100,956 2.32 48% n/a n/a 0 48,459
D-2 56,634 1.30 85% LID D2 Rain Garden 1,639 48,139
D-3 73,190 1.68 85% LID D3 Rain Garden 2,120 62,212
D-4 40,380 0.93 85% LID D4 Rain Garden 1,170 34,323
Total 1,802,741 41.39 42,844 1,161,741
Project Number:Project:
Project Location:
Calculations By:Date:
Sq. Ft. Acres
LID A5 96,267 2.21 85% A5 Storm Tech 2,324 2,789 81,827
LID A6 41,817 0.96 85% A6 Storm Tech 1,009 1,211 35,544
LID B2 134,165 3.08 85% B2 Rain Garden 3,239 3,887 114,040
LID B3 84,918 1.95 85% B3 Storm Tech 2,050 2,460 72,180
LID B5 73,190 1.68 85% B5 Rain Garden 1,767 2,120 62,212
LID C2 189,920 4.36 85% C2,3,4 Storm Tech 4,584 5,501 161,432
LID C5 101,059 2.32 85% C5 Rain Garden 2,439 2,927 85,900
LID C6 92,347 2.12 85% C6 Rain Garden 2,229 2,675 78,495
LID C8 30,492 0.70 85% C8 Gravel Bioretention 736 883 25,918
LID D2 56,634 1.30 85% D2 Rain Garden 1,366 1,639 48,139
LID D3 73,190 1.68 85% D3 Rain Garden 1,767 2,120 62,212
LID D4 40,380 0.93 85% D4 Rain Garden 975 1,170 34,323
Total 877,732 20.15 29,382 862,223
1,802,741 ft2
1,161,741 ft2
299,519 ft2
862,223 ft2
580,871 ft2
871,306 ft3
862,223 ft2
74%
Total Net Proposed Impervious Area
50% Requried Minium Area to be Treated
Total Treated Area
Percent Impervious Treated by LID
A1, A2, A3, A4, A5, A7, A8, B1, C1, C7, D1
75% Requried Minium Area to be Treated
LID Site Summary
Total Site Area
Total Impervious Area
Total Impervious Area without LID Treatment
Impervious
Area (ft2)
Subbasin
ID Treatment TypeLID ID Volume per
UD-BMP (ft3)
Vol. w/20%
Increase per
Fort Collins
Manual (ft3)
Area Weighted %
Impervious
1536-001 Sanctuary on the Green
Fort Collins, Colorado
C. Ungerman 11/3/2021
LID Summary
LID Summary per LID Structure
LID Summary
AreaBasin ID Treatment TypePercent
Impervious LID ID
Sanctuary on the Green
11/3/2021
1536-001
Fort Collins, Colorado
C. Ungerman
Total
Impervious
Area (ft2)
Required
Volume (ft3)
LID Summary per Basin
Sheet 1 of 2
Designer:
Company:
Date:
Project:
Location:
1. Basin Storage Volume
A) Effective Imperviousness of Tributary Area, Ia Ia =85.0 %
(100% if all paved and roofed areas upstream of rain garden)
B) Tributary Area's Imperviousness Ratio (i = Ia/100)i = 0.850
C) Water Quality Capture Volume (WQCV) for a 12-hour Drain Time WQCV = 0.29 watershed inches
(WQCV= 0.8 * (0.91* i3 - 1.19 * i2 + 0.78 * i)
D) Contributing Watershed Area (including rain garden area) Area = 134,165 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 = in
Average Runoff Producing Storm
G) For Watersheds Outside of the Denver Region, VWQCV OTHER =cu ft
Water Quality Capture Volume (WQCV) Design Volume
H) User Input of Water Quality Capture Volume (WQCV) Design Volume VWQCV USER =3,887 cu ft
(Only if a different WQCV Design Volume is desired)
2. Basin Geometry
A) WQCV Depth (12-inch maximum)DWQCV =12 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 =2281 sq ft
D) Actual Flat Surface Area AActual =sq ft
E) Area at Design Depth (Top Surface Area)ATop =sq ft
F) Rain Garden Total Volume VT=cu ft
(VT= ((ATop + AActual) / 2) * Depth)
3. Growing Media
4. Underdrain System
A) Are underdrains provided?1
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)
C. Ungerman
Northern Engineering
November 3, 2021
Sanctuary West
LID B2
UD-BMP (Version 3.07, March 2018)
Choose One
Choose One
18" Rain Garden Growing Media
Other (Explain):
YES
NO
UD-BMP_v3.07_LID-B2, RG 11/3/2021, 10:59 AM
Sheet 2 of 2
Designer:
Company:
Date:
Project:
Location:
5. Impermeable Geomembrane Liner and Geotextile Separator Fabric
A) Is an impermeable liner provided due to proximity
of structures or groundwater contamination?
6. Inlet / Outlet Control
A) Inlet Control
7. Vegetation
8. Irrigation
A) Will the rain garden be irrigated?
Notes:
Design Procedure Form: Rain Garden (RG)
C. Ungerman
Northern Engineering
November 3, 2021
Sanctuary West
LID B2
Choose One
Choose One
Choose One
Sheet Flow- No Energy Dissipation Required
Concentrated Flow- Energy Dissipation Provided
Plantings
Seed (Plan for frequent weed control)
Sand Grown or Other High Infiltration Sod
Choose One
YES
NO
YES
NO
UD-BMP_v3.07_LID-B2, RG 11/3/2021, 10:59 AM
Sheet 1 of 2
Designer:
Company:
Date:
Project:
Location:
1. Basin Storage Volume
A) Effective Imperviousness of Tributary Area, Ia Ia =85.0 %
(100% if all paved and roofed areas upstream of rain garden)
B) Tributary Area's Imperviousness Ratio (i = Ia/100)i = 0.850
C) Water Quality Capture Volume (WQCV) for a 12-hour Drain Time WQCV = 0.29 watershed inches
(WQCV= 0.8 * (0.91* i3 - 1.19 * i2 + 0.78 * i)
D) Contributing Watershed Area (including rain garden area) Area = 73,190 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 = in
Average Runoff Producing Storm
G) For Watersheds Outside of the Denver Region, VWQCV OTHER =cu ft
Water Quality Capture Volume (WQCV) Design Volume
H) User Input of Water Quality Capture Volume (WQCV) Design Volume VWQCV USER =2,120 cu ft
(Only if a different WQCV Design Volume is desired)
2. Basin Geometry
A) WQCV Depth (12-inch maximum)DWQCV =12 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 =1244 sq ft
D) Actual Flat Surface Area AActual =sq ft
E) Area at Design Depth (Top Surface Area)ATop =sq ft
F) Rain Garden Total Volume VT=cu ft
(VT= ((ATop + AActual) / 2) * Depth)
3. Growing Media
4. Underdrain System
A) Are underdrains provided?1
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)
C. Ungerman
Northern Engineering
November 3, 2021
Sanctuary West
LID B5
UD-BMP (Version 3.07, March 2018)
Choose One
Choose One
18" Rain Garden Growing Media
Other (Explain):
YES
NO
UD-BMP_v3.07_LID-B5, RG 11/3/2021, 10:58 AM
Sheet 2 of 2
Designer:
Company:
Date:
Project:
Location:
5. Impermeable Geomembrane Liner and Geotextile Separator Fabric
A) Is an impermeable liner provided due to proximity
of structures or groundwater contamination?
6. Inlet / Outlet Control
A) Inlet Control
7. Vegetation
8. Irrigation
A) Will the rain garden be irrigated?
Notes:
Design Procedure Form: Rain Garden (RG)
C. Ungerman
Northern Engineering
November 3, 2021
Sanctuary West
LID B5
Choose One
Choose One
Choose One
Sheet Flow- No Energy Dissipation Required
Concentrated Flow- Energy Dissipation Provided
Plantings
Seed (Plan for frequent weed control)
Sand Grown or Other High Infiltration Sod
Choose One
YES
NO
YES
NO
UD-BMP_v3.07_LID-B5, RG 11/3/2021, 10:58 AM
Sheet 1 of 2
Designer:
Company:
Date:
Project:
Location:
1. Basin Storage Volume
A) Effective Imperviousness of Tributary Area, Ia Ia =85.0 %
(100% if all paved and roofed areas upstream of rain garden)
B) Tributary Area's Imperviousness Ratio (i = Ia/100)i = 0.850
C) Water Quality Capture Volume (WQCV) for a 12-hour Drain Time WQCV = 0.29 watershed inches
(WQCV= 0.8 * (0.91* i3 - 1.19 * i2 + 0.78 * i)
D) Contributing Watershed Area (including rain garden area) Area = 101,059 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 = in
Average Runoff Producing Storm
G) For Watersheds Outside of the Denver Region, VWQCV OTHER =cu ft
Water Quality Capture Volume (WQCV) Design Volume
H) User Input of Water Quality Capture Volume (WQCV) Design Volume VWQCV USER =2,927 cu ft
(Only if a different WQCV Design Volume is desired)
2. Basin Geometry
A) WQCV Depth (12-inch maximum)DWQCV =12 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 =1718 sq ft
D) Actual Flat Surface Area AActual =sq ft
E) Area at Design Depth (Top Surface Area)ATop =sq ft
F) Rain Garden Total Volume VT=cu ft
(VT= ((ATop + AActual) / 2) * Depth)
3. Growing Media
4. Underdrain System
A) Are underdrains provided?1
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)
C. Ungerman
Northern Engineering
November 3, 2021
Sanctuary West
LID C5
UD-BMP (Version 3.07, March 2018)
Choose One
Choose One
18" Rain Garden Growing Media
Other (Explain):
YES
NO
UD-BMP_v3.07_LID-C5, RG 11/3/2021, 11:02 AM
Sheet 2 of 2
Designer:
Company:
Date:
Project:
Location:
5. Impermeable Geomembrane Liner and Geotextile Separator Fabric
A) Is an impermeable liner provided due to proximity
of structures or groundwater contamination?
6. Inlet / Outlet Control
A) Inlet Control
7. Vegetation
8. Irrigation
A) Will the rain garden be irrigated?
Notes:
Design Procedure Form: Rain Garden (RG)
C. Ungerman
Northern Engineering
November 3, 2021
Sanctuary West
LID C5
Choose One
Choose One
Choose One
Sheet Flow- No Energy Dissipation Required
Concentrated Flow- Energy Dissipation Provided
Plantings
Seed (Plan for frequent weed control)
Sand Grown or Other High Infiltration Sod
Choose One
YES
NO
YES
NO
UD-BMP_v3.07_LID-C5, RG 11/3/2021, 11:02 AM
Sheet 1 of 2
Designer:
Company:
Date:
Project:
Location:
1. Basin Storage Volume
A) Effective Imperviousness of Tributary Area, Ia Ia =85.0 %
(100% if all paved and roofed areas upstream of rain garden)
B) Tributary Area's Imperviousness Ratio (i = Ia/100)i = 0.850
C) Water Quality Capture Volume (WQCV) for a 12-hour Drain Time WQCV = 0.29 watershed inches
(WQCV= 0.8 * (0.91* i3 - 1.19 * i2 + 0.78 * i)
D) Contributing Watershed Area (including rain garden area) Area = 92,347 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 = in
Average Runoff Producing Storm
G) For Watersheds Outside of the Denver Region, VWQCV OTHER =cu ft
Water Quality Capture Volume (WQCV) Design Volume
H) User Input of Water Quality Capture Volume (WQCV) Design Volume VWQCV USER =2,675 cu ft
(Only if a different WQCV Design Volume is desired)
2. Basin Geometry
A) WQCV Depth (12-inch maximum)DWQCV =12 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 =1570 sq ft
D) Actual Flat Surface Area AActual =sq ft
E) Area at Design Depth (Top Surface Area)ATop =sq ft
F) Rain Garden Total Volume VT=cu ft
(VT= ((ATop + AActual) / 2) * Depth)
3. Growing Media
4. Underdrain System
A) Are underdrains provided?1
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)
C. Ungerman
Northern Engineering
November 3, 2021
Sanctuary West
LID C6
UD-BMP (Version 3.07, March 2018)
Choose One
Choose One
18" Rain Garden Growing Media
Other (Explain):
YES
NO
UD-BMP_v3.07_LID-C6, RG 11/3/2021, 11:04 AM
Sheet 2 of 2
Designer:
Company:
Date:
Project:
Location:
5. Impermeable Geomembrane Liner and Geotextile Separator Fabric
A) Is an impermeable liner provided due to proximity
of structures or groundwater contamination?
6. Inlet / Outlet Control
A) Inlet Control
7. Vegetation
8. Irrigation
A) Will the rain garden be irrigated?
Notes:
Design Procedure Form: Rain Garden (RG)
C. Ungerman
Northern Engineering
November 3, 2021
Sanctuary West
LID C6
Choose One
Choose One
Choose One
Sheet Flow- No Energy Dissipation Required
Concentrated Flow- Energy Dissipation Provided
Plantings
Seed (Plan for frequent weed control)
Sand Grown or Other High Infiltration Sod
Choose One
YES
NO
YES
NO
UD-BMP_v3.07_LID-C6, RG 11/3/2021, 11:04 AM
Project Title Date:
Project Number Calcs By:
Client
Basins
0.8
WQCV = Watershed inches of Runoff (inches)85%
a = Runoff Volume Reduction (constant)
i = Total imperviousness Ratio (i = Iwq/100)0.290 in
A =2.21 ac
V = 0.0533 ac-ft
V = Water Quality Design Volume (ac-ft)
WQCV = Water Quality Capture Volume (inches)
A = Watershed Area (acres)
2324 cu. ft.
Drain Time
a =
i =
WQCV =
Figure EDB-2 - Water Quality Capture Volume (WQCV), 80th Percentile Runoff Event
Sanctuary on the Green November 3, 2021
1536-001 M. Ruebel
Basin A5
0.231
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0.45
0.5
00.10.20.30.40.50.60.70.80.91WQCV (watershed inches)Total Imperviousness Ratio (i = Iwq/100)
Water Quality Capture Volume
6 hr
12 hr
24 hr
40 hr
()iii78.019.10.91aWQCV 23 +-=
()iii78.019.10.91aWQCV 23 +-=
AV*
12
WQCV
=
12 hr
Project Title Date:
Project Number Calcs By:
Client
Basins
0.8
WQCV = Watershed inches of Runoff (inches)85%
a = Runoff Volume Reduction (constant)
i = Total imperviousness Ratio (i = Iwq/100)0.290 in
A =0.96 ac
V = 0.0232 ac-ft
V = Water Quality Design Volume (ac-ft)
WQCV = Water Quality Capture Volume (inches)
A = Watershed Area (acres)
1009 cu. ft.
Drain Time
a =
i =
WQCV =
Figure EDB-2 - Water Quality Capture Volume (WQCV), 80th Percentile Runoff Event
Sanctuary on the Green November 3, 2021
1536-001 M. Ruebel
Basin A6
0.231
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0.45
0.5
00.10.20.30.40.50.60.70.80.91WQCV (watershed inches)Total Imperviousness Ratio (i = Iwq/100)
Water Quality Capture Volume
6 hr
12 hr
24 hr
40 hr
()iii78.019.10.91aWQCV 23 +-=
()iii78.019.10.91aWQCV 23 +-=
AV*
12
WQCV
=
12 hr
Project Title Date:
Project Number Calcs By:
Client
Basins
0.8
WQCV = Watershed inches of Runoff (inches)85%
a = Runoff Volume Reduction (constant)
i = Total imperviousness Ratio (i = Iwq/100)0.290 in
A =1.95 ac
V = 0.0471 ac-ft
V = Water Quality Design Volume (ac-ft)
WQCV = Water Quality Capture Volume (inches)
A = Watershed Area (acres)
2050 cu. ft.
Drain Time
a =
i =
WQCV =
Figure EDB-2 - Water Quality Capture Volume (WQCV), 80th Percentile Runoff Event
Sanctuary on the Green November 3, 2021
1536-001 M. Ruebel
Basin B3
0.231
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0.45
0.5
00.10.20.30.40.50.60.70.80.91WQCV (watershed inches)Total Imperviousness Ratio (i = Iwq/100)
Water Quality Capture Volume
6 hr
12 hr
24 hr
40 hr
()iii78.019.10.91aWQCV 23 +-=
()iii78.019.10.91aWQCV 23 +-=
AV*
12
WQCV
=
12 hr
Project Title Date:
Project Number Calcs By:
Client
Basins
0.8
WQCV = Watershed inches of Runoff (inches)85%
a = Runoff Volume Reduction (constant)
i = Total imperviousness Ratio (i = Iwq/100)0.290 in
A =4.36 ac
V = 0.1052 ac-ft
V = Water Quality Design Volume (ac-ft)
WQCV = Water Quality Capture Volume (inches)
A = Watershed Area (acres)
4584 cu. ft.
Drain Time
a =
i =
WQCV =
Figure EDB-2 - Water Quality Capture Volume (WQCV), 80th Percentile Runoff Event
Sanctuary on the Green November 3, 2021
1536-001 M. Ruebel
Basin C2
0.231
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0.45
0.5
00.10.20.30.40.50.60.70.80.91WQCV (watershed inches)Total Imperviousness Ratio (i = Iwq/100)
Water Quality Capture Volume
6 hr
12 hr
24 hr
40 hr
()iii78.019.10.91aWQCV 23 +-=
()iii78.019.10.91aWQCV 23 +-=
AV*
12
WQCV
=
12 hr
Pond No :
Basin A5
WQ
0.87
12.00 min 1736 ft3
2.21 acres 0.04 ac-ft
Max Release Rate =0.51 cfs
Time (min)
Ft Collins
WQ
Intensity
(in/hr)
Inflow
Volume
(ft3)
Outflow
Adjustment
Factor
Qav
(cfs)
Outflow Volume
(ft3)
Storage Volume
(ft3)
5 1.425 822 1.00 0.51 153 669
10 1.105 1275 1.00 0.51 306 969
15 0.935 1618 0.90 0.46 413 1205
20 0.805 1857 0.80 0.41 490 1368
25 0.715 2062 0.74 0.38 566 1496
30 0.650 2250 0.70 0.36 643 1607
35 0.585 2362 0.67 0.34 719 1643
40 0.535 2469 0.65 0.33 796 1673
45 0.495 2570 0.63 0.32 872 1698
50 0.460 2653 0.62 0.32 949 1705
55 0.435 2760 0.61 0.31 1025 1735
60 0.410 2838 0.60 0.31 1102 1736
65 0.385 2887 0.59 0.30 1178 1709
70 0.365 2947 0.59 0.30 1255 1693
75 0.345 2985 0.58 0.30 1331 1654
80 0.330 3046 0.58 0.29 1408 1638
85 0.315 3089 0.57 0.29 1484 1605
90 0.305 3167 0.57 0.29 1561 1606
95 0.290 3178 0.56 0.29 1637 1541
100 0.280 3230 0.56 0.29 1714 1517
105 0.270 3271 0.56 0.28 1790 1480
110 0.260 3299 0.55 0.28 1867 1433
115 0.255 3383 0.55 0.28 1943 1440
120 0.245 3392 0.55 0.28 2020 1372
*Note: Using the method described in Urban Storm Drainage Criteria Manual Volume 2.
A =
Tc =
Project Location :
Design Point
C =
Design Storm
DETENTION POND CALCULATION; MODIFIED FAA METHOD w/ Ft Collins IDF
Input Variables Results
Required Detention Volume
Fort Collins, Colorado
1536-001
Sanctuary
Project Number :
Project Name :
Chambers A5
Page 5 of 11
1536-001 Chamber Summary_MCR
Pond No :
Basin A6
WQ
0.87
11.00 min 744 ft3
0.96 acres 0.02 ac-ft
Max Release Rate =0.23 cfs
Time (min)
Ft Collins
WQ
Intensity
(in/hr)
Inflow
Volume
(ft3)
Outflow
Adjustment
Factor
Qav
(cfs)
Outflow Volume
(ft3)
Storage Volume
(ft3)
5 1.425 357 1.00 0.23 69 288
10 1.105 554 1.00 0.23 138 416
15 0.935 703 0.87 0.20 179 523
20 0.805 807 0.78 0.18 214 593
25 0.715 896 0.72 0.17 248 647
30 0.650 977 0.68 0.16 283 694
35 0.585 1026 0.66 0.15 317 709
40 0.535 1072 0.64 0.15 352 720
45 0.495 1116 0.62 0.14 386 730
50 0.460 1153 0.61 0.14 421 732
55 0.435 1199 0.60 0.14 455 744
60 0.410 1233 0.59 0.14 490 743
65 0.385 1254 0.58 0.13 524 730
70 0.365 1280 0.58 0.13 559 721
75 0.345 1297 0.57 0.13 593 703
80 0.330 1323 0.57 0.13 628 695
85 0.315 1342 0.56 0.13 662 679
90 0.305 1376 0.56 0.13 697 679
95 0.290 1381 0.56 0.13 731 649
100 0.280 1403 0.56 0.13 766 637
105 0.270 1421 0.55 0.13 800 620
110 0.260 1433 0.55 0.13 835 598
115 0.255 1470 0.55 0.13 869 600
120 0.245 1473 0.55 0.13 904 569
*Note: Using the method described in Urban Storm Drainage Criteria Manual Volume 2.
C =
Tc =
A =
Chambers A6
Input Variables Results
Design Point
Design Storm Required Detention Volume
Project Location : Fort Collins, Colorado
DETENTION POND CALCULATION; MODIFIED FAA METHOD w/ Ft Collins IDF
Project Number : 1536-001
Project Name : Sanctuary
Page 6 of 11
1536-001 Chamber Summary_MCR
Pond No :
Basin B3
WQ
0.87
12.00 min 1002 ft3
1.95 acres 0.02 ac-ft
Max Release Rate =0.78 cfs
Time (min)
Ft Collins
WQ
Intensity
(in/hr)
Inflow
Volume
(ft3)
Outflow
Adjustment
Factor
Qav
(cfs)
Outflow Volume
(ft3)
Storage Volume
(ft3)
5 1.425 725 1.00 0.78 234 491
10 1.105 1125 1.00 0.78 468 657
15 0.935 1428 0.90 0.70 632 796
20 0.805 1639 0.80 0.62 749 890
25 0.715 1819 0.74 0.58 866 954
30 0.650 1985 0.70 0.55 983 1002
35 0.585 2084 0.67 0.52 1100 984
40 0.535 2178 0.65 0.51 1217 962
45 0.495 2267 0.63 0.49 1334 934
50 0.460 2341 0.62 0.48 1451 890
55 0.435 2435 0.61 0.48 1568 868
60 0.410 2504 0.60 0.47 1685 819
65 0.385 2547 0.59 0.46 1802 745
70 0.365 2601 0.59 0.46 1919 682
75 0.345 2634 0.58 0.45 2036 598
80 0.330 2687 0.58 0.45 2153 534
85 0.315 2725 0.57 0.45 2270 456
90 0.305 2794 0.57 0.44 2387 407
95 0.290 2804 0.56 0.44 2504 301
100 0.280 2850 0.56 0.44 2621 229
105 0.270 2886 0.56 0.43 2738 148
110 0.260 2911 0.55 0.43 2855 56
115 0.255 2985 0.55 0.43 2972 13
120 0.245 2993 0.55 0.43 3089 -96
*Note: Using the method described in Urban Storm Drainage Criteria Manual Volume 2.
C =
Tc =
A =
Chambers B3
Input Variables Results
Design Point
Design Storm Required Detention Volume
Project Location : Fort Collins, Colorado
DETENTION POND CALCULATION; MODIFIED FAA METHOD w/ Ft Collins IDF
Project Number : 1536-001
Project Name : Sanctuary
Page 7 of 11
1536-001 Chamber Summary_MCR
Pond No :
Basin C2
WQ
0.87
15.00 min 2925 ft3
4.36 acres 0.07 ac-ft
Max Release Rate =1.20 cfs
Time (min)
Ft Collins
WQ
Intensity
(in/hr)
Inflow
Volume
(ft3)
Outflow
Adjustment
Factor
Qav
(cfs)
Outflow Volume
(ft3)
Storage Volume
(ft3)
5 1.425 1622 1.00 1.20 360 1262
10 1.105 2515 1.00 1.20 720 1795
15 0.935 3192 1.00 1.20 1080 2112
20 0.805 3664 0.88 1.05 1260 2404
25 0.715 4068 0.80 0.96 1440 2628
30 0.650 4438 0.75 0.90 1620 2818
35 0.585 4660 0.71 0.86 1800 2860
40 0.535 4870 0.69 0.83 1980 2890
45 0.495 5070 0.67 0.80 2160 2910
50 0.460 5235 0.65 0.78 2340 2895
55 0.435 5445 0.64 0.76 2520 2925
60 0.410 5599 0.63 0.75 2700 2899
65 0.385 5695 0.62 0.74 2880 2815
70 0.365 5815 0.61 0.73 3060 2755
75 0.345 5889 0.60 0.72 3240 2649
80 0.330 6008 0.59 0.71 3420 2588
85 0.315 6094 0.59 0.71 3600 2494
90 0.305 6247 0.58 0.70 3780 2467
95 0.290 6270 0.58 0.69 3960 2310
100 0.280 6373 0.58 0.69 4140 2233
105 0.270 6452 0.57 0.69 4320 2132
110 0.260 6509 0.57 0.68 4500 2009
115 0.255 6674 0.57 0.68 4680 1994
120 0.245 6691 0.56 0.68 4860 1831
*Note: Using the method described in Urban Storm Drainage Criteria Manual Volume 2.
C =
Tc =
A =
Chambers C2
Input Variables Results
Design Point
Design Storm Required Detention Volume
Project Location : Fort Collins, Colorado
DETENTION POND CALCULATION; MODIFIED FAA METHOD w/ Ft Collins IDF
Project Number : 1536-001
Project Name : Sanctuary
Page 8 of 11
1536-001 Chamber Summary_MCR
Vault IDTotal RequiredWQ Volume(cf)Flow,WQ(cfs)ChamberTypeChamber Release Ratea(cfs)ChamberVolumeb(cf)Installed Camber w/ Aggregatec(cf)Mimimum No. of ChambersdTotal Release Ratee(cfs)Required Storage Volume by FAA Method(cf)Mimimum No. of ChambersfProvided ChambersProvided Release Storage Provided within the Chambersg(cf)Total Installed System Volumeh(cf)StormTech Chamber A5 2789 0.02 MC-4500 0.028 106.50 162.60 18 0.51 1736 17 18 0.51 1917 2927StormTech Chamber A6 1211 0.01 MC-4500 0.028 106.50 162.60 8 0.23 744 7 8 0.23 852 1301StormTech Chamber B3 2460 0.02 SC-740 0.024 45.90 74.90 33 0.78 1002 22 33 0.78 1515 2472StormTech Chamber C2 5501 0.04 MC-3500 0.038 109.90 175.00 32 1.20 2925 27 32 1.20 3517 5600*20% Added per FC requirementsSC-740a. Release rate per chamber, limited by flow through geotextile with accumulated sediment.b. Volume within chamber only, not accounting for void spaces in surrounding aggregate.c. Volume includes chamber and void spaces (40%) in surrounding aggregate, per chamber unit.d. Number of chambers required to provide full WQCV within total installed system, including aggregate.e. Release rate per chamber times number of chambers.f. Number of chambers required to provide required FAA storage volume stored within the chamber only (no aggregate storage).g. Volume provided in chambers only (no aggregate storage). This number must meet or exceed the required FAA storage volume.h. System volume includes total number of chambers, plus surrounding aggregate. This number must meet or exceed the required WQCV.Chamber Configuration SummaryD:\Projects\1536-001\Drainage\LID\1536-001 Chamber Summary_MCR
Chamber Dimensions SC-160 SC-310 SC-740 MC-3500 MC-4500
Width (in) 34.0 34.0 51.0 77.0 100.0
Length (in)85.4 85.4 85.4 90.0 52.0
Height (in)16.0 16.0 30.0 45.0 60.0
Floor Area (sf)20.2 20.2 30.2 48.1 36.1
Chamber Volume (cf)6.9 14.7 45.9 109.9 106.5
Chamber/Aggregate Volume (cf)29.3 29.3 74.9 175.0 162.6
Flow Rate* 0.35 gpm/sf
1 cf =7.48052 gal
1 gallon =0.133681 cf
1 GPM = 0.002228 cfs
*Flow rate based on 1/2 of Nov 07 QMAX in Figure 17 of UNH Testing Report
SC-160 SC-310 SC-740 MC-3500 MC-4500
Flow Rate/chamber (cfs)0.015724 0.015724 0.023586 0.037528 0.028159
end caps have a volume of 108.7 cu. ft.
StormTech Chamber Data
Chamber Flow Rate
Chamber Flow Rate Conversion (gpm/sf to cfs)
end caps have a volume of 45.1 cu. ft.
D:\Projects\1536-001\Drainage\LID\1536-001 Chamber Summary_MCR
Project: 1536-001
By: ATC
Date: 3/24/21
Pond ID
100-Yr.
Detention Vol.
(Ac-Ft)
Water Quality
Capture Volume (Ac-
Ft)
Total Req'd
Vol. (Ac-Ft)
Peak
Release
(cfs)
Pond 1 0.95 N/A 0.47 15.80
Pond 2 3.71 N/A 3.71 15.50
Pond 3 4.01 0.48 4.49 14.90
Pond 4 0.35 N/A 0.35 5.70
Pond 5 0.47 N/A 0.47 5.60
POND SUMMARY TABLE
Pond Stage-Storage Curve
Pond: 1
Project: 1536-001
By: ATC
Date: 09/20/2020
Stage
(FT)
Contour Area
(SF)
Volume
(CU.FT.)
Volume
(AC-FT)
5,063.800 38.72 0.00 0.00
5,064.000 175.77 19.80 0.00
5,064.200 348.35 71.24 0.00
5,064.400 567.70 161.95 0.00
5,064.600 820.49 300.00 0.01
5,064.800 1,097.81 491.16 0.01
5,065.000 1,485.88 748.55 0.02
5,065.200 1,889.18 1085.25 0.02
5,065.400 2,312.57 1504.71 0.03
5,065.600 2,837.21 2018.79 0.05
5,065.800 3,588.94 2659.94 0.06
5,066.000 4,425.00 3459.87 0.08
5,066.200 5,287.46 4429.84 0.10
5,066.400 6,344.11 5591.40 0.13
5,066.600 7,403.16 6964.76 0.16
5,066.800 8,477.96 8551.66 0.20
5,067.000 9,940.41 10391.56 0.24
5,067.200 11,239.08 12508.18 0.29
5,067.400 12,708.86 14901.47 0.34
5,067.600 14,175.65 17588.58 0.40
5,067.800 15,708.17 20575.65 0.47
5,068.000 17,606.53 23905.32 0.55
5,068.200 19,484.29 27612.82 0.63
5,068.200 11.01 27612.82 0.63
5,068.400 21,164.56 29056.71 0.67
5,068.600 22,752.61 33447.47 0.77
5,068.800 24,352.79 38157.10 0.88
5,069.000 25,963.16 43187.84 0.99
5,069.200 27,579.88 48541.33 1.11
5,069.400 29,215.12 54220.04 1.24
Pond Stage-Storage Curve
Pond: 2
Project: 1536-001
By: ATC
Date: 3/23/21
Stage
(FT)
Contour Area
(SF)
Volume
(CU.FT.)
Volume
(AC-FT)
5054.20 294.01 0.00 0.00
5054.40 1090.97 130.09 0.00
5054.60 1998.65 434.51 0.01
5054.80 2972.65 928.43 0.02
5055.00 4011.85 1624.28 0.04
5055.20 5121.04 2535.32 0.06
5055.40 6301.95 3675.58 0.08
5055.60 7555.21 5059.40 0.12
5055.80 8881.13 6701.25 0.15
5056.00 10283.08 8615.96 0.20
5056.20 11768.14 10819.41 0.25
5056.40 13343.53 13328.93 0.31
5056.60 15008.31 16162.48 0.37
5056.80 16751.27 19336.85 0.44
5057.00 18564.58 22866.88 0.52
5057.20 20450.01 26766.82 0.61
5057.40 22419.70 31052.28 0.71
5057.60 24506.51 35743.36 0.82
5057.80 27047.91 40896.71 0.94
5058.00 28496.11 46450.48 1.07
5058.20 29938.73 52293.37 1.20
5058.40 31379.04 58424.58 1.34
5058.60 32816.91 64843.64 1.49
5058.80 34252.26 71550.05 1.64
5059.00 35684.92 78543.28 1.80
5059.20 37114.94 85822.79 1.97
5059.40 38542.06 93388.05 2.14
5059.60 39966.26 101238.45 2.32
5059.80 41389.10 109373.57 2.51
5060.00 42816.84 117793.76 2.70
5060.2 44249.73 126500.02 2.90
5060.4 45687.65 135493.38 3.11
5060.6 47130.46 144774.81 3.32
5060.8 48578.25 154345.32 3.54
5061 50030.86 164205.87 3.77
5061.2 51488.14 174357.43 4.00
5061.4 52950.27 184800.93 4.24
5061.6 54416.92 195537.31 4.49
5061.8 55869.57 206565.64 4.74
Pond Stage-Storage Curve
Pond: 3
Project: 1536-001
By: ATC
Date: 3/23/21
Stage
(FT)
Contour Area
(SF)
Volume
(CU.FT.)
Volume
(AC-FT)
5,048.20 495.29 0.00 0.00
5,048.40 1729.71 210.04 0.00
5,048.60 3574.38 729.41 0.02
5,048.80 5970.19 1673.68 0.04
5,049.00 8509.79 3114.20 0.07
5,049.20 11031.66 5062.90 0.12
5,049.40 13542.10 7515.99 0.17
5,049.60 16046.52 10471.31 0.24
5,049.80 18549.79 13927.92 0.32
5,050.00 21056.76 17885.93 0.41
5,050.20 23566.68 22345.92 0.51
5,050.40 26077.90 27308.26 0.63
5,050.60 28594.27 32773.54 0.75
5,050.80 31026.08 38733.92 0.89
5,051.00 33232.17 45158.48 1.04
5,051.20 35365.29 52017.12 1.19
5,051.40 37521.02 59304.69 1.36
5,051.60 39686.60 67024.44 1.54
5,051.80 42151.80 75207.04 1.73
5,052.00 45209.71 83941.41 1.93
5,052.20 48997.93 93359.63 2.14
5,052.40 53561.54 103612.20 2.38
5,052.60 58545.04 114819.16 2.64
5,052.80 63716.83 127041.70 2.92
5,053.00 68682.66 140278.54 3.22
5,053.20 72882.04 154432.94 3.55
5,053.40 75629.58 169283.25 3.89
5,053.60 77963.05 184641.92 4.24
5,053.80 80317.76 200469.42 4.60
5,054.00 82779.44 216778.52 4.98
Pond Stage-Storage Curve
Pond: 4
Project: 1536-001
By: ATC
Date: 09/20/2020
Stage
(FT)
Contour Area
(SF)
Volume
(CU.FT.)
Volume
(AC-FT)
5,059.800 163.55 0.00 0.00
5,060.000 831.59 90.93 0.00
5,060.200 1,546.62 325.08 0.01
5,060.400 2,422.91 718.77 0.02
5,060.600 3,283.58 1287.24 0.03
5,060.800 4,276.40 2041.06 0.05
5,061.000 5,325.59 2999.34 0.07
5,061.200 6,434.43 4173.60 0.10
5,061.400 7,594.77 5574.91 0.13
5,061.600 8,428.25 7176.49 0.16
5,061.800 8,972.03 8916.24 0.20
5,062.000 9,514.00 10764.58 0.25
5,062.200 10,054.33 12721.16 0.29
5,062.400 10,593.31 14785.69 0.34
5,062.600 11,131.10 16957.91 0.39
5,062.800 11,668.18 19237.62 0.44
5,063.000 12,204.55 21624.70 0.50
5,063.200 12,741.59 24119.12 0.55
5,063.400 13,280.18 26721.11 0.61
5,063.600 13,821.72 29431.12 0.68
5,063.800 14,366.00 32249.71 0.74
5,064.000 14,912.76 35177.42 0.81
5,064.200 15,462.09 38214.74 0.88
5,064.400 16,014.44 41362.23 0.95
Pond Stage-Storage Curve
Pond: 5
Project: 1536-001
By: ATC
Date: 3/23/21
Stage
(FT)
Contour Area
(SF)
Volume
(CU.FT.)
Volume
(AC-FT)
5052.80 20.82 0.00 0.00
5053.00 1078.36 18.87 83.27
5053.20 4007.78 90.31 560.94
5053.40 9087.72 246.05 1836.30
5053.60 15754.99 512.36 4290.20
5053.80 22110.38 913.99 8058.83
5054.00 28475.79 1472.42 13104.04
5054.20 35380.33 2203.41 19477.17
5054.40 42474.13 3120.29 27251.82
5054.60 49113.97 4234.90 36402.60
5054.80 55422.65 5556.76 46849.91
EPA STORM WATER MANAGEMENT MODEL - VERSION 5.1 (Build 5.1.014)
--------------------------------------------------------------
*********************************************************
NOTE: The summary statistics displayed in this report are
based on results found at every computational time step,
not just on results from each reporting time step.
*********************************************************
****************
Analysis Options
****************
Flow Units ............... CFS
Process Models:
Rainfall/Runoff ........ YES
RDII ................... NO
Snowmelt ............... NO
Groundwater ............ NO
Flow Routing ........... YES
Ponding Allowed ........ NO
Water Quality .......... NO
Infiltration Method ...... HORTON
Flow Routing Method ...... KINWAVE
Starting Date ............ 11/21/2012 00:00:00
Ending Date .............. 11/22/2012 06:00:00
Antecedent Dry Days ...... 0.0
Report Time Step ......... 00:15:00
Wet Time Step ............ 00:05:00
Dry Time Step ............ 01:00:00
Routing Time Step ........ 30.00 sec
************************** Volume Depth
Runoff Quantity Continuity acre-feet inches
************************** --------- -------
Total Precipitation ...... 12.928 3.669
Evaporation Loss ......... 0.000 0.000
Infiltration Loss ........ 2.821 0.801
Surface Runoff ........... 9.997 2.837
SWMM 5 Page 1
Final Storage ............ 0.179 0.051
Continuity Error (%) ..... -0.537
************************** Volume Volume
Flow Routing Continuity acre-feet 10^6 gal
************************** --------- ---------
Dry Weather Inflow ....... 0.000 0.000
Wet Weather Inflow ....... 9.997 3.258
Groundwater Inflow ....... 0.000 0.000
RDII Inflow .............. 0.000 0.000
External Inflow .......... 0.000 0.000
External Outflow ......... 9.991 3.256
Flooding Loss ............ 0.000 0.000
Evaporation Loss ......... 0.000 0.000
Exfiltration Loss ........ 0.000 0.000
Initial Stored Volume .... 0.000 0.000
Final Stored Volume ...... 0.000 0.000
Continuity Error (%) ..... 0.055
********************************
Highest Flow Instability Indexes
********************************
Link P_2_Out (6)
Link P_1_Out (4)
Link P_4_Out (2)
*************************
Routing Time Step Summary
*************************
Minimum Time Step : 30.00 sec
Average Time Step : 30.00 sec
Maximum Time Step : 30.00 sec
Percent in Steady State : 0.00
Average Iterations per Step : 1.00
Percent Not Converging : 0.00
***************************
SWMM 5 Page 2
Subcatchment Runoff Summary
***************************
------------------------------------------------------------------------------------------------------------------------------
Total Total Total Total Imperv Perv Total Total Peak Runoff
Precip Runon Evap Infil Runoff Runoff Runoff Runoff Runoff Coeff
Subcatchment in in in in in in in 10^6 gal CFS
------------------------------------------------------------------------------------------------------------------------------
1 3.67 0.00 0.00 0.80 1.80 1.04 2.83 0.76 60.97 0.773
2 3.67 0.00 0.00 0.65 2.16 0.82 2.98 1.08 87.10 0.812
4 3.67 0.00 0.00 0.71 1.98 0.94 2.92 0.28 23.53 0.796
3 3.67 0.00 0.00 0.88 1.69 1.07 2.76 0.80 61.39 0.752
5 3.67 0.00 0.00 1.09 1.15 1.41 2.56 0.34 24.41 0.698
******************
Node Depth Summary
******************
---------------------------------------------------------------------------------
Average Maximum Maximum Time of Max Reported
Depth Depth HGL Occurrence Max Depth
Node Type Feet Feet Feet days hr:min Feet
---------------------------------------------------------------------------------
outfall OUTFALL 0.00 0.00 100.00 0 00:00 0.00
P_1 STORAGE 0.27 4.07 110.07 0 01:03 4.06
P_2 STORAGE 0.74 5.09 109.09 0 02:17 5.08
P_3 STORAGE 1.11 4.18 106.18 0 04:07 4.18
P_4 STORAGE 0.14 2.46 108.46 0 01:01 2.46
P_5 STORAGE 0.25 3.10 107.10 0 01:14 3.10
*******************
Node Inflow Summary
*******************
-------------------------------------------------------------------------------------------------
Maximum Maximum Lateral Total Flow
Lateral Total Time of Max Inflow Inflow Balance
Inflow Inflow Occurrence Volume Volume Error
Node Type CFS CFS days hr:min 10^6 gal 10^6 gal Percent
SWMM 5 Page 3
-------------------------------------------------------------------------------------------------
outfall OUTFALL 0.00 14.90 0 02:27 0 3.26 0.000
P_1 STORAGE 60.97 60.97 0 00:40 0.757 0.757 0.037
P_2 STORAGE 87.10 101.37 0 00:40 1.08 2.12 0.017
P_3 STORAGE 61.39 74.21 0 00:40 0.801 3.26 0.026
P_4 STORAGE 23.53 23.53 0 00:40 0.283 0.283 0.047
P_5 STORAGE 24.41 24.41 0 00:40 0.335 0.335 0.050
*********************
Node Flooding Summary
*********************
No nodes were flooded.
**********************
Storage Volume Summary
**********************
--------------------------------------------------------------------------------------------------
Average Avg Evap Exfil Maximum Max Time of Max Maximum
Volume Pcnt Pcnt Pcnt Volume Pcnt Occurrence Outflow
Storage Unit 1000 ft3 Full Loss Loss 1000 ft3 Full days hr:min CFS
--------------------------------------------------------------------------------------------------
P_1 2.078 1 0 0 41.472 17 0 01:03 15.00
P_2 18.187 3 0 0 161.615 26 0 02:17 15.50
P_3 37.688 4 0 0 174.972 17 0 04:06 14.90
P_4 0.683 0 0 0 15.104 6 0 01:01 5.69
P_5 1.258 1 0 0 20.340 9 0 01:13 5.64
***********************
Outfall Loading Summary
***********************
-----------------------------------------------------------
Flow Avg Max Total
Freq Flow Flow Volume
Outfall Node Pcnt CFS CFS 10^6 gal
-----------------------------------------------------------
SWMM 5 Page 4
outfall 50.03 8.06 14.90 3.256
-----------------------------------------------------------
System 50.03 8.06 14.90 3.256
********************
Link Flow Summary
********************
-----------------------------------------------------------------------------
Maximum Time of Max Maximum Max/ Max/
|Flow| Occurrence |Veloc| Full Full
Link Type CFS days hr:min ft/sec Flow Depth
-----------------------------------------------------------------------------
P_1_Out DUMMY 15.00 0 00:54
P_2_Out DUMMY 15.50 0 01:01
P_3_Out DUMMY 14.90 0 02:27
P_4_Out DUMMY 5.69 0 01:01
P_5_Out DUMMY 5.64 0 01:14
*************************
Conduit Surcharge Summary
*************************
No conduits were surcharged.
Analysis begun on: Wed Mar 24 10:13:19 2021
Analysis ended on: Wed Mar 24 10:13:19 2021
Total elapsed time: < 1 sec
SWMM 5 Page 5
Link P_1_Out Flow (CFS)
Elapsed Time (hours)
35302520151050Flow (CFS)16.0
14.0
12.0
10.0
8.0
6.0
4.0
2.0
0.0
SWMM 5 Page 1
Node P_1 Volume (ft3)
Elapsed Time (hours)
302520151050Volume (ft3)45000.0
40000.0
35000.0
30000.0
25000.0
20000.0
15000.0
10000.0
5000.0
0.0
SWMM 5 Page 1
Elapsed Time (hours)
35302520151050Flow (CFS)16.0
14.0
12.0
10.0
8.0
6.0
4.0
2.0
0.0
Link P_2_Out Flow (CFS)
SWMM 5 Page 1
Elapsed Time (hours)
35302520151050Volume (ft3)180000.0
160000.0
140000.0
120000.0
100000.0
80000.0
60000.0
40000.0
20000.0
0.0
Node P_2 Volume (ft3)
SWMM 5 Page 1
Elapsed Time (hours)
35302520151050Flow (CFS)16.0
14.0
12.0
10.0
8.0
6.0
4.0
2.0
0.0
Link P_3_Out Flow (CFS)
SWMM 5 Page 1
Elapsed Time (hours)
35302520151050Volume (ft3)180000.0
160000.0
140000.0
120000.0
100000.0
80000.0
60000.0
40000.0
20000.0
0.0
Node P_3 Volume (ft3)
SWMM 5 Page 1
Link P_4_Out Flow (CFS)
Elapsed Time (hours)
35302520151050Flow (CFS)6.0
5.0
4.0
3.0
2.0
1.0
0.0
SWMM 5 Page 1
Node P_4 Volume (ft3)
Elapsed Time (hours)
35302520151050Volume (ft3)16000.0
14000.0
12000.0
10000.0
8000.0
6000.0
4000.0
2000.0
0.0
SWMM 5 Page 1
Elapsed Time (hours)
35302520151050Flow (CFS)6.0
5.0
4.0
3.0
2.0
1.0
0.0
Link P_5_Out Flow (CFS)
SWMM 5 Page 1
Elapsed Time (hours)
35302520151050Volume (ft3)25000.0
20000.0
15000.0
10000.0
5000.0
0.0
Node P_5 Volume (ft3)
SWMM 5 Page 1
APPENDIX E
Erosion Control Report
MAP POCKET
TSALPOLYND
D D
ONOTPOLLTEUCTILEIRONRAINSTOWATERWAYSUTSALPOLYND
DDONOTPOLLTEUCTILEIRONRAINSTOWATERWAYS
U
TSALPOLYND
DD
ONOTPOLLTEUCTILEIRONRAINSTOWATERWAYSU
TSALPOLYND
DDONOTPOLLTEUCTILEIRONRAINSTOWATERWAYSU
TSALPOLYND
DD
ONOTPOLLTEUCTILEIRONRAINSTOWATERWAYSU
TSALPOLYND
D DONOTPOLLTEUCTILEIRONRAINSTOWATERWAYSU
TSALPOLYNDDDONOTPOLLTEUCTILEIRONRAINSTOWATERWAYS
U
TSALPOLYND
DDONOTPOLLTEUCTILEIRONRAINSTOWATERWAYSU
TSALPOLYND
DDONOTPOLLTEUCTILEIRONRAINSTOWATERWAYS
U
TSALPOLYNDDDONOTPOLLTEUCTILEIRONRAINSTOWATERWAYS
U
TSALPOLYND
DDONOTPOLLTEUCTILEIRONRAINSTOWATERWAYSU TSALPOLYNDDDONOTPOLLTEUCTILEIRONRAINSTOWATERWAYSU
TSALPOLYND
DDONOTPOLLTEUCTILEIRONRAINSTOWATERWAYSU
TSALPOLYND
DD
ONOTPOLLTEUCTILEIRONRAINSTOWATERWAYSU
TSALPOLYNDDDONOTPOLLTEUCTILEIRONRAINSTOWATERWAYS
U
TSALPOLYNDDDONOTPOLLTEUCTILEIRONRAINSTOWATERWAYS
U EEEEEEEEEE
EEEE
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ONOTPOLLTEUCTILEIRONRAINSTOWATERWAYSU
TSALPOLYND
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NYLOPLAST
DO NOT POLLUTE DRAINS TO WATERWAYS
E
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XXXWWVAULTELEC
OWNER
KIRK WILSON
W CHERRY STREET
OWNER
KIRK & DEBRA WILSON
320 N SUNSET STREET
OWNER
KIRK WILSON
310 N SUNSET STREET
OWNER
FRANK ERNSET
242 N SUNSET STREET
OWNER
KIRI SAFTLER
230 N SUNSET STREET
OWNER
POUDRE R-1
SCHOOL DISTRICT
2444 LAPORTE AVE
OWNER
POUDRE R-1
SCHOOL DISTRICT
2444 LAPORTE AVE
OWNER
FORREST SCHRUPP
2318 LAPORTE AVE
OWNER
CALVARY BAPTIST TEMPLE
2420 LAPORTE AVENUE
OWNERRICHARD & DIXIELOYD2316 LAPORTEAVENUEOWNERSYDNE ARCHAMBAULT2314 LAPORTE AVENUEOWNERCURTIS LYONSLAPORTE AVENUEOWNERALEX OZOLS2224 LAPORTE AVENUEOWNERDANNY ROGERS2214 LAPORTE AVENUEOWNERROBERT JONES2218 LAPORTE AVENUEOWNER
PATRICK ST.
CLAIR
2216 LAPORTE
AVENUE
OWNER
KURT VATTANO
OWNER
WILLIAM GREYBAR
413 N TAFT HILL ROAD
OWNER
ANDREA GABEL
420 N IMPALA DR.
OWNER
CITY OF FORT COLLINS
OWNER
FAITH REALTY
OWNER
MIRANDA SPINDEL
330 N TAFT HILL ROAD
OWNER
LAPORT OUTREACH
MINISTRIES INC.
220 N TAFT HILL ROAD
OWNER
CITY OF FORT COLLINS
OWNER
7-ELEVEN
200 N TAFT HILL ROAD
OWNER
CITY OF FORT COLLINS
OWNER
POUDRE R-1
SCHOOL DISTRICT
2444 LAPORTE AVE
OWNER
POUDRE R-1
SCHOOL DISTRICT
2444 LAPORTE AVE
GREEN ACRES
SUBDIVISION
GREEN ACRES
SUBDIVISION
BELLWETHER FARM
SUBDIVISION
PROPOSED STORMTECH
MC 4500 DETENTION
CHAMBERS A6
PROPOSED STORMTECH
SC-740 DETENTION
CHAMBERS B3
DETENTION
POND 3
DETENTION
POND 2
DETENTION / WQ
POND 1
DETENTION
POND 4
DETENTION / WQ
POND 5
RAIN GARDEN D5
RAIN
GARDEN D3
RAIN
GARDEN B2
RAIN
GARDEN D3
RAIN
GARDEN C5
RAIN
GARDEN C6
PROPOSED STORMTECH
MC 4500 DETENTION
CHAMBERS C2
RAIN
GARDEN D4N IMPALA DRIVEIRISH DRIVEWEBB AVENUEPENNSYLVANIA STREETLAPORTE AVENUE
LAPORTE AVENUE N TAFT HILL ROADN TAFT HILL ROADLAPORTE AVENUE
S IMPALA DRIVEBRIARWOOD ROADACCESS DRIVEN
E
W
M
E
R
C
E
R
D
I
T
C
H
NEW MERCER
D
ITCH
NEW
M
E
R
C
E
R
D
I
T
C
H
NEW
M
E
R
C
E
R
DI
T
C
H
STREET A
STREET C
STREET B1.13 ac.
A-7
0.89 ac.
A-4
3.08 ac.
B-2
1.09 ac.
C-4
3.63 ac.
C-1
0.52 ac.
A-8
2.88 ac.
A-1
1.07 ac.
B-4
2.21 ac.
A-5
0.31 ac.
A-3
2.41 ac.
B-1
1.95 ac.
B-3
0.93 ac.
D-4
2.18 ac.
C-2
2.32 ac.
C-5
2.20 ac.
C-72.32 ac.
D-1
1.30 ac.
D-2
1.68 ac.
D-3
0.96 ac.
A-6
0.88 ac.
A-2
1.09 ac.
C-3
1.64 ac.
B-5
0.70 ac.
C-8
GRAVEL
BIORETENTION
100-YR
FLOODWAY
100-YR
FLOODPLAIN
100-YR
FLOODWAY
100-YR
FLOODPLAIN
100-YR
FLOODWAY
100-YR
FLOODPLAIN
100-YR
FLOODPLAIN
GRAVEL
BIORETENTION
2.12 ac.
C-6
B M
KEYMAP
LAPORTE AVE.TAFT HILL RD.SheetSANCTUARY ON THE GREENSThese drawings areinstruments of serviceprovided by NorthernEngineering Services, Inc.and are not to be used forany type of constructionunless signed and sealed bya Professional Engineer inthe employ of NorthernEngineering Services, Inc.NOT FOR CONSTRUCTIONREVIEW SETENGINEERNGIEHTRONRNFORT COLLINS: 301 North Howes Street, Suite 100, 80521GREELEY: 820 8th Street, 80631970.221.4158northernengineering.comof 30
NORTH
C6.00DRAINAGE EXHIBIT29
( IN FEET )
1 inch = ft.
Feet0120120
120
240 360
CALL UTILITY NOTIFICATION CENTER OF
COLORADO
Know what's below.
before you dig.Call
R
LEGEND:
5013
PROPOSED CONTOUR 93
EXISTING CONTOUR
PROPERTY BOUNDARY
EXISTING STORM SEWER
1.THE SIZE, TYPE AND LOCATION OF ALL KNOWN UNDERGROUND UTILITIES ARE
APPROXIMATE WHEN SHOWN ON THESE DRAWINGS. IT SHALL BE THE
RESPONSIBILITY OF THE CONTRACTOR TO VERIFY THE EXISTENCE OF ALL
UNDERGROUND UTILITIES IN THE AREA OF THE WORK. BEFORE COMMENCING
NEW CONSTRUCTION, THE CONTRACTOR SHALL BE RESPONSIBLE FOR LOCATING
ALL UNDERGROUND UTILITIES AND SHALL BE RESPONSIBLE FOR FOR ALL
UNKNOWN UNDERGROUND UTILITIES.
2.REFER TO THE"Preliminary Drainage Report for Sanctuary West dated March 24, 2021"
FOR ADDITIONAL INFORMATION.
NOTES:
FLOW PATH
DRAINAGE BASIN BUBBLE
A
DESIGN POINT A
BASIN BOUNDARY
PROPOSED STORM SEWER
FOR DRAINAGE REVIEW ONLY
NOT FOR CONSTRUCTION
FLOODPLAIN NOTES:
1.REFER TO THE PLAT FOR LOT AREAS, TRACT SIZES, EASEMENTS, LOT DIMENSIONS,
UTILITY EASEMENTS, OTHER EASEMENTS, AND OTHER SURVEY INFORMATION
2.THIS PROJECT IS LOCATED WITHIN A FEMA 100-YEAR FLOODWAY AND FLOOD
FRINGE AND MUST COMPLY WITH CHAPTER 10 OF THE CITY CODE.
3.ALL ELEVATIONS DEPICTED IN PLAN VIEW AND BENCHMARKS LISTED HEREON ARE
PER NAVD 88 DATUM.
4.ANY ITEMS LOCATED IN THE FLOODWAY THAT CAN FLOAT (E.G., PICNIC TABLES,
BIKE RACKS, ETC.) MUST BE ANCHORED.
5.THE LOWEST FLOOR AND THE FINISHED FLOOR FOR ANY BUILDING IN THE
FLOODPLAIN SHALL BE FLOODPROOFED UP TO THE REGULATORY FLOOD
PROTECTION ELEVATION.
6.A FLOODPLAIN USE PERMIT SHALL BE REQUIRED FOR EACH SITE CONSTRUCTION
ELEMENT IN THE FLOODPLAIN.
7.A FLOODPLAIN USE PERMIT AND NO RISE CERTIFICATION IS REQUIRED PRIOR TO
PERFORMING ANY WORK WITHIN THE FLOODWAY (I.E., CURB CUT REMOVAL,
LANDSCAPING).
8.NO STORAGE OF MATERIALS OR EQUIPMENT SHALL BE ALLOWED IN THE
FLOODWAY, WHETHER TEMPORARY (DURING CONSTRUCTION) OR PERMANENT.
LANDSCAPING SHALL ALSO MEET THE REQUIREMENTS FOR NO RISE IN THE
FLOODWAY.
9.REFER TO THE PRELIMINARY DRAINAGE REPORT FOR SANCTUARY WEST DATED
MARCH 24, 2021 FOR ADDITIONAL INFORMATION.
POND SUMMARY TABLE
Pond ID
100-Yr.
Detention
Vol. (Ac-Ft)
Water Quality
Capture Volume
(Ac-Ft)
Total Req'd
Vol. (Ac-Ft)
Peak
Release
(cfs)
Pond 1 0.95 N/A 0.47 15.80
Pond 2 3.71 N/A 3.71 15.50
Pond 3 4.01 0.48 4.49 14.90
Pond 4 0.35 N/A 0.35 5.70
Pond 5 0.47 N/A 0.47 5.60
Design
Point Basin(s)Area, A
(acres)
2-yr
Tc
(min)
10-yr
Tc
(min)
100-yr
Tc
(min)
C2 C10 C100
Intensity,
i2
(in/hr)
Intensity,
i10
(in/hr)
Intensity,
i100
(in/hr)
Flow,
Q2
(cfs)
Flow,
Q10
(cfs)
Flow,
Q100
(cfs)
WQ Flow
(cfs)
A1 A1 2.88 10 10 10 0.25 0.25 0.31 2.21 3.78 7.72 1.59 2.72 6.95 0.80
A2 A2 0.88 7 7 7 0.87 0.87 1.00 2.60 4.44 9.06 1.99 3.41 7.97 1.00
A3 A3 0.31 6 6 6 0.87 0.87 1.00 2.67 4.56 9.63 0.72 1.23 2.99 0.36
A4 A4 0.89 9 9 8 0.87 0.87 1.00 2.35 4.02 8.38 1.83 3.12 7.46 0.91
A5 A5 2.21 12 12 11 0.87 0.87 1.00 2.09 3.57 7.42 4.03 6.88 16.40 2.02
A6 A6 0.96 11 11 10 0.87 0.87 1.00 2.13 3.63 7.72 1.79 3.04 7.41 0.89
A7 A7 1.13 11 11 11 0.87 0.87 1.00 2.13 3.63 7.57 2.10 3.58 8.55 1.05
A8 A8 0.53 12 12 12 0.87 0.87 1.00 2.05 3.50 7.29 0.94 1.60 3.83 0.47
B1 B1 2.41 10 10 10 0.25 0.25 0.31 2.21 3.78 7.72 1.33 2.28 5.81 0.67
B2 B2 3.08 12 12 12 0.67 0.67 0.84 2.05 3.50 7.16 4.24 7.24 18.52 2.12
B3 B3 1.95 12 12 11 0.87 0.87 1.00 2.09 3.57 7.42 3.56 6.07 14.47 1.78
B4 B4 1.07 10 10 10 0.87 0.87 1.00 2.21 3.78 7.72 2.06 3.52 8.26 1.03
B5 B5 1.64 12 12 12 0.87 0.87 1.00 2.09 3.57 7.29 2.99 5.10 11.96 1.50
C1 C1 3.63 10 10 10 0.25 0.25 0.31 2.21 3.78 7.72 2.01 3.43 8.76 1.00
C2 C2 2.18 14 14 14 0.87 0.87 1.00 1.95 3.34 6.82 3.71 6.36 14.86 1.86
C3 C3 1.09 12 12 12 0.87 0.87 1.00 2.05 3.50 7.16 1.94 3.32 7.80 0.97
C4 C4 1.09 5 5 5 0.87 0.87 1.00 2.85 4.87 9.95 2.71 4.63 10.85 1.36
C5 C5 2.32 6 6 5 0.87 0.87 1.00 2.76 4.72 9.95 5.59 9.55 23.08 2.80
C6 C6 2.12 6 6 5 0.87 0.87 1.00 2.76 4.72 9.95 5.12 8.74 21.12 2.56
C7 C7 2.20 11 11 11 0.87 0.87 1.00 2.17 3.71 7.57 4.17 7.12 16.65 2.08
C8 C8 0.70 6 6 6 0.87 0.87 1.00 2.67 4.56 9.63 1.63 2.78 6.74 0.81
D1 D1 2.32 8 8 8 0.61 0.61 0.77 2.40 4.10 8.38 3.42 5.84 14.92 1.71
D2 D2 1.30 11 11 11 0.87 0.87 1.00 2.17 3.71 7.57 2.46 4.21 9.84 1.23
D3 D3 1.68 12 12 12 0.82 0.82 1.00 2.09 3.57 7.29 2.87 4.90 12.25 1.44
D4 D4 0.93 9 9 9 0.87 0.87 1.00 2.30 3.93 8.21 1.87 3.19 7.63 0.93