HomeMy WebLinkAboutTHE UNION ON ELIZABETH (FORMERLY 1208 W. ELIZABETH STREET) - FDP - FDP170024 - SUBMITTAL DOCUMENTS - ROUND 3 - DRAINAGE REPORTDecember 27, 2017
FINAL DRAINAGE AND
EROSION CONTROL REPORT FOR
UNION ON ELIZABETH
Fort Collins, Colorado
Prepared for:
Plum Owner Ft Collins CO LLC
999 South Shady Grove Road, Suite 600
Memphis, TN 38120
Prepared by:
301 N. Howes, Suite 100
Fort Collins, Colorado 80521
Phone: 970.221.4158 Fax: 970.221.4159
www.northernengineering.com
Project Number: 1252-005
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.
December 27, 2017
City of Fort Collins
Stormwater Utility
700 Wood Street
Fort Collins, Colorado 80521
RE: Final Drainage and Erosion Control Report for
UNION ON ELIZABETH
Dear Staff:
Northern Engineering is pleased to submit this Final Drainage and Erosion Control Report for your
review. This report accompanies the Final Plan submittal for the proposed “Union on Elizabeth”
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 Project Engineer
Union on Elizabeth
Final Drainage Report
TABLE OF CONTENTS
I. GENERAL LOCATION AND DESCRIPTION ................................................................... 1
A. Location ............................................................................................................................................. 1
B. Description of Property ..................................................................................................................... 2
C. Floodplain.......................................................................................................................................... 4
II. DRAINAGE BASINS AND SUB-BASINS ....................................................................... 6
A. Major Basin Description .................................................................................................................... 6
B. Sub-Basin Description ....................................................................................................................... 6
III. DRAINAGE DESIGN CRITERIA ................................................................................... 7
A. Regulations........................................................................................................................................ 7
B. Four Step Process .............................................................................................................................. 7
C. Development Criteria Reference and Constraints ............................................................................ 7
D. Hydrological Criteria ......................................................................................................................... 8
E. Hydraulic Criteria .............................................................................................................................. 8
F. Modifications of Criteria ................................................................................................................... 8
IV. DRAINAGE FACILITY DESIGN .................................................................................... 8
A. General Concept ............................................................................................................................... 8
B. Specific Details .................................................................................................................................. 9
V. CONCLUSIONS ...................................................................................................... 10
A. Compliance with Standards ............................................................................................................ 10
B. Drainage Concept ............................................................................................................................ 10
APPENDICES:
APPENDIX A – Hydrologic Computations, Historic Drainage Exhibit
APPENDIX B - USDA Soils Information
APPENDIX C – Hydraulic Computations
APPENDIX D – Water Quality Calculations, LID Information
APPENDIX E – Detention Calculations
APPENDIX F – Erosion Control Report
APPENDIX G – Current Effective FIRM Panel
Union on Elizabeth
Final Drainage Report
LIST OF FIGURES:
Figure 1 – Aerial Photograph ................................................................................................ 2
Figure 2– Proposed Site Plan ................................................................................................ 3
Figure 3 – Existing Floodplains ............................................................................................. 4
MAP POCKET:
Proposed Drainage Exhibit
Union on Elizabeth
Final 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 15, 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 west of the intersection of South Shields St. and West
Elizabeth Street.
4. The project site lies within the Old Town Master Drainage Basin. Per the Old Town
Master Drainage Plan, onsite detention is required. Onsite detention is required for the
runoff volume difference between the 100 year developed inflow rate and the 2 year
historic release rate.
5. LID water quality treatment as well as extended detention will be provided on site, as
described in further detail below.
Union on Elizabeth
Final Drainage Report 2
6. As this is an infill site, much of the area surrounding the site is fully developed.
7. Offsite flows enter the site from the north and west. We have accounted for these
offsite flows and will safely convey 100-year offsite flows through the site and
discharge flows into the adjacent W. Elizabeth Street Right of Way. Offsite flows will
be treated as a “pass-through” design and will not receive water quality treatment or
detention. We have defined two offsite basins as shown in the Historic Drainage
Exhibit provided in Appendix A. Further discussion of these basins and flow
quantities are provided below.
B. Description of Property
1. The development area is roughly 2.2 net acres.
Figure 1 – Aerial Photograph
2. The subject property is currently composed of existing buildings, and landscaped
areas. Existing ground slopes are mild to moderate (i.e., 1 - 3±%) through the
interior of the property. General topography slopes from northwest to southeast.
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 consists of Nunn Clay Loam, which falls into Hydrologic Soil Group C.
4. The proposed project site plan is composed of the development of a student housing
development and amenities. Associated site work, water, and sewer lines will be
constructed with the development. Onsite water quality treatment is proposed and
will consist of several features which are discussed in Section IV, below.
PROJECT SITE
Union on Elizabeth
Final Drainage Report 3
Figure 2– Proposed Site Plan
5. There are no known irrigation laterals crossing the site.
6. The proposed land use is mixed-use.
Union on Elizabeth
Final Drainage Report 4
C. Floodplain
1. The project site is not encroached by any FEMA 100-year floodplain, please see
Appendix G for a copy of FIRM Map Number 08069C0978G (Revised 5/2/2012).
However, the City-designated 100-year flood fringe of W. Elizabeth does encroach
along the southern border of the site. Additionally, the project site is affected by the
CSU Underpass CLOMR, which, at the direction of City Stormwater Staff, is to be
considered best available data. We have obtained the data from this CLOMR, and
have utilized the data for establishing base (100-year) flood elevations through the
site.
Figure 3 –Area Floodplain Mapping
2. A minimum of 18-inches of freeboard will be provided from base (100-year) flood
elevation (BFE) in adjacent Right of Way. This freeboard level will be applied to
either the design of finished floor elevations, or the minimum level of flood proofing
measures.
PROJECT SITE
Union on Elizabeth
Final Drainage Report 5
3. The base (100-year) flood elevation in the vicinity of the proposed west building is
5029.30, which is referenced to the NAVD 88 Datum. This flood elevation was
interpolated at the upstream (southwest) corner of the proposed west building.
Please see Table 1 and Figure 1, below.
4. The base (100-year) flood elevation in the vicinity of the proposed east building is
5028.80, which is referenced to the NAVD 88 Datum. This flood elevation was
interpolated at the upstream (southwest) corner of the proposed east building. Please
see Table 2 and Figure 1, below.
TABLE 1 – West Building Flood Summary Table
TABLE 2 – East Building Flood Summary Table
Union on Elizabeth
Final Drainage Report 6
FIGURE 1 – Foundation Detail
5. The vertical datum utilized for site survey work is the City of Fort Collins Benchmark
#20-97 (Elevation=5050.15; NAVD 88).
6. It is noted that some of the surrounding developments have used the NGVD 29
(unadjusted) datum. The conversion from NAVD 88 to NGVD 29 (unadjusted) datum
is -3.18-ft.
7. Foundation for the retail/residential structures will be a combination of slab on grade
and a basement foundation.
8. A floodplain use permit will be required for each structure and each site construction
element in the floodplain. The floodplain use permit for each building will be
approved at the time of building permit application.
9. Critical Facilities are not allowed in the floodplain. There will be no Critical Facilities
in the floodplain associated with this project.
10. An elevation certificate will be completed before the Certificate of Occupancy (C.O.) is
issued.
II. DRAINAGE BASINS AND SUB-BASINS
A. Major Basin Description
1. The project site lies within the Old Town Master Drainage Basin. Per the Old Town
Master Drainage Plan, onsite detention is required. Onsite detention is required for the
runoff volume difference between the 100-year developed inflow rate and the 2-year
historic release rate.
B. Sub-Basin Description
1. The subject property historically drains overland from the northwest to the southeast.
Runoff from the majority of the site has historically been collected in the adjacent W.
Elizabeth Street.
2. A more detailed description of the project drainage patterns is provided below.
Union on Elizabeth
Final Drainage Report 7
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.
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:
Paver System with StormTech Chambers
Sand Filter
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 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:
A portion of the site will be treated via a paver system with StormTech chambers,
providing filtration of suspended solids.
The upper level of the proposed parking garage will be treated via a sand filter
provided in the lower level of the structure.
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.
Union on Elizabeth
Final Drainage Report 8
Elevations of existing downstream facilities that the subject property will release to
will be maintained.
Existing flows from the north and west will need to be safely conveyed through the
proposed site.
D. Hydrological Criteria
1. The City of Fort Collins Rainfall Intensity-Duration-Frequency Curves, as depicted in
Figure RA-16 of the FCSCM, serve as the source for all hydrologic computations
associated with the proposed development. Tabulated data contained in Table RA-7
has been utilized for Rational Method runoff calculations.
2. The Rational Method has been employed to compute stormwater runoff utilizing
coefficients contained in Tables RO-11 and RO-12 of the FCSCM.
3. Three separate design storms have been utilized to address distinct drainage
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.
4. 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 City designated floodplain.
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 proposed paver system with StormTech
chambers, sand filter within the parking structure, as discussed further below.
3. Drainage patterns anticipated for drainage basins shown in the Drainage Exhibit are
described below.
Basin 1
Basin 1 is primarily composed of landscaped areas and an alleyway. This basin will
drain via alleyway curb and gutter into a curb chase, which will direct runoff into W.
Union on Elizabeth
Final Drainage Report 9
Elizabeth Street. Runoff from this basin will not be detained; therefore, the overall site
release rate will reduced to compensate for this undetained release.
Basin 2, 3
Basins 2 and 3 are composed primarily of rooftop and parking garage areas. These
basins will generally drain via internal piping systems within the proposed buildings.
Runoff from Basin 2 will be detained within the StormTech chamber system
underneath the proposed paver system. Runoff from Basin 3 will be detained and
also receive LID treatment within a concrete vault/sand filter, as discussed further
below. The proposed concrete vault in Basin 3 will release into a storm line system
which will outfall to the adjacent north curb and gutter of W. Elizabeth Street. The
paver subdrain system will also outfall to this storm line system and be conveyed to
the adjacent north curb and gutter of W. Elizabeth Street.
Basin 4
Basin 4 is composed of landscaped areas and an access drive. This basin will
generally drain via swale flow to a curb chase into W. Elizabeth Street. Runoff from
this basin will not be detained; therefore, the overall site release rate will reduced to
compensate for this undetained release.
Basins OS1 and OS2
Basin OS1 is composed of offsite drainage areas to the west of the site. These areas
are fully developed with portions of the basin consisting of multi-family development
and portions consisting of paved parking areas. An offsite basin exhibit has been
provided in Appendix A, as well as peak 100-year discharge calculations. Peak 100-
year discharge from this basin will be conveyed in a proposed alley section with pan,
and will be safely conveyed south along the site western boundary into the north curb
and gutter of W. Elizabeth Street.
Basin OS 2 consists of the recently developed “Scott Plaza” (Ref. 7). The offsite basin
exhibit provided in Appendix A shows the extents of this basin and peak 100-year
discharge calculations are also provided in this appendix section. Peak 100-year
discharge from this basin will be conveyed south as sheet flow across the proposed
paver system within Basin 2 and into the north curb and gutter of W. Elizabeth Street.
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. Two onsite detention facilities will be provided within the site. A chamber
detention system will be provided within the subgrade of the paver system
proposed within Drainage Basin 2. The paver system will serve as LID
treatment and provide filtration. The underlying StormTech chamber system
will provide detention. A concrete vault detention system will be provided
within the building envelope shown within Drainage Basin 3.
2. Based on calculations provided in Appendix E, the required detention volume
for the proposed concrete vault is 0.039 Ac-Ft, with a peak 100-year release
rate of 5.20 cfs.
3. Based on calculations provided in Appendix E, the required detention volume
for the proposed chamber system within the subgrade of the paver system is
Union on Elizabeth
Final Drainage Report 10
0.077 Ac-Ft, with a peak 100-year release rate of 0.75 cfs
4. Emergency overflow conveyance paths and calculations for both detention
facilities is provided in Appendix E.
5. A total combined release rate has been determined for the proposed detention
facilities has been set at 5.95 cfs. This release rate has been determined
based on the methodology utilized for previous projects in close proximity to
the current project (approved Final Drainage Report for “The Retreat at 1200
Plum”, Ref. 6; approved Final Drainage Report for “Scott Plaza”, Ref. 7). The
methodology accounts for impervious area that is allowed to be
“grandfathered”. There is 1.44 acres of impervious area within the
development site which drains to W. Elizabeth Street. A 100-year discharge
from this impervious area of 9.83 cfs has been calculated. There is 0.84
acres of pervious area within the development site which also drains to W.
Elizabeth Street. A 2-year discharge of 0.34 cfs has been calculated from this
pervious area. The sum of “grandfathered” impervious area discharge into W.
Elizabeth Street combined with 2-year pervious area discharge is 10.17 cfs,
which is considered as the allowable peak release rate for the site. We have
subtracted the 100-year undetained discharge computed from Basins 1, and 4
(4.22 cfs total) for an allowable release rate of 10.17-4.22=5.95 cfs.
6. LID features within the site include a paver system in Basin 2, and a sand
filter in Basin 3. Please refer to Appendix C for an LID Exhibit and all
pertinent calculations and information. As shown in Appendix C, the proposed
LID treatment design exceeds the 75% treatment requirement.
7. Stormwater facility Standard Operating Procedures (SOP) will be provided by
the City of Fort Collins in the Development Agreement.
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 Old
Town Master Drainage Basin.
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 Old Town Master Drainage Basin.
Union on Elizabeth
Final Drainage Report 11
References
1. Fort Collins Stormwater Criteria Manual, City of Fort Collins, Colorado, as adopted by Ordinance No.
174, 2011, and referenced in Section 26-500 (c) of the City of Fort Collins Municipal Code.
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.
4. Downtown River District (DTRD) Final Design Report, Ayres Associates, February 2012.
5. Urban Storm Drainage Criteria Manual, Volumes 1-3, Urban Drainage and Flood Control
District, Wright-McLaughlin Engineers, Denver, Colorado.
6. Final Drainage and Erosion Control Report for The Retreat at 1200 Plum, Northern
Engineering, April 22, 2009.
7. Final Drainage and Erosion Control Report for Scott Plaza, Northern Engineering, June
10, 2014.
APPENDIX A
Hydrologic Computations, Historic Drainage Exhibit
CHARACTER OF SURFACE:
Runoff
Coefficient
Percentage
Impervious Project: 1252-005
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.
1 8411 0.19 0.00 0.13 0.00 0.00 0.07 0.71 0.71 1.00 59.1%
2 27151 0.62 0.00 0.00 0.38 0.13 0.11 0.73 0.73 0.92 63.8%
3 45112 1.04 0.00 0.00 1.04 0.00 0.00 0.95 0.95 1.00 90.0%
4 16045 0.37 0.00 0.18 0.00 0.04 0.14 0.63 0.63 0.79 49.5%
OS1 128502 2.95 2.28 0.07 0.51 0.16 -0.07 0.92 0.92 1.00 97.2%
OS2 9583 0.22 0.00 0.19 0.00 0.00 0.03 0.85 0.85 1.00 77.7%
Historic Site
(Pervious Area) 34761 0.80 0.00 0.00 0.00 0.00 0.80 0.25 0.25 0.31 0.0%
Historic Site
Overland Flow, Time of Concentration:
Project: 1252-005
Calculations By:
Date:
Gutter/Swale Flow, Time of Concentration:
Tt = L / 60V
Tc = T
i + Tt
(Equation RO-2)
Velocity (Gutter Flow), V = 20·S
½
Velocity (Swale Flow), V = 15·S
½
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)
Rational Method Equation: Project: 1252-005
Calculations By:
Date:
From Section 3.2.1 of the CFCSDDC
Rainfall Intensity:
1 1 0.19 8 8 8 0.71 0.71 1.00 2.40 4.10 8.59 0.33 0.56 1.66
2 2 0.62 9 9 9 0.73 0.73 0.92 2.30 3.93 8.21 1.05 1.80 4.69
3 3 1.04 5 5 5 0.95 0.95 1.00 2.85 4.87 9.95 2.80 4.79 10.30
4 4 0.37 12 12 11 0.63 0.63 0.79 2.05 3.50 7.42 0.47 0.81 2.15
OS1 OS1 2.95 9 9 8 0.92 0.92 1.00 2.30 3.93 8.59 6.21 10.61 25.34
OS2 OS2 0.22 7 7 6 0.85 0.85 1.00 2.52 4.31 9.31 0.47 0.81 2.05
Historic Site
(Pervious
Area)
Historic Site
(Pervious Area) 0.80 16 16 15 0.25 0.25 0.31 1.81 3.08 6.62 0.36 0.61 1.65
Historic Site
(Impervious
Area)
Historic Site
(Impervious Area) 1.42 14 14 13 0.95 0.95 1.00 1.92 3.29 6.92 2.59 4.44 9.84
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
November 27, 2017
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)
OS1
H1
OS2
OS1
OS2
H1
ENGINEER ING HISTORIC DRAINAGE EXHIBIT
N O R T H E RN
08.01.17
D:\PROJECTS\1252-005\DWG\DRNG\1252-005_HIST_DRNG.DWG
( IN FEET )
1 inch = ft.
100 0 100 Feet
100
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
Natural Area, Colorado
Resources
Conservation
Service
August 14, 2017
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
74—Nunn clay loam, 1 to 3 percent slopes.................................................13
76—Nunn clay loam, wet, 1 to 3 percent slopes.........................................14
References............................................................................................................16
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
4491550 4491560 4491570 4491580 4491590 4491600 4491610 4491620 4491630 4491640 4491650
4491550 4491560 4491570 4491580 4491590 4491600 4491610 4491620 4491630 4491640 4491650
491630 491640 491650 491660 491670 491680 491690 491700 491710 491720 491730 491740 491750 491760 491770 491780 491790
491630 491640 491650 491660 491670 491680 491690 491700 491710 491720 491730 491740 491750 491760 491770 491780 491790
40° 34' 32'' N
105° 5' 56'' W
40° 34' 32'' N
105° 5' 48'' W
40° 34' 28'' N
105° 5' 56'' W
40° 34' 28'' N
105° 5' 48'' W
N
Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 13N WGS84
0 35 70 140 210
Feet
0 10 20 40 60
Meters
Map Scale: 1:771 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
Map Unit Legend
Larimer County Area, Colorado (CO644)
Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI
74 Nunn clay loam, 1 to 3 percent
slopes
2.2 91.9%
76 Nunn clay loam, wet, 1 to 3
percent slopes
0.2 8.1%
Totals for Area of Interest 2.4 100.0%
Map Unit Descriptions
The map units delineated on the detailed soil maps in a soil survey represent the
soils or miscellaneous areas in the survey area. The map unit descriptions, along
with the maps, can be used to determine the composition and properties of a unit.
A map unit delineation on a soil map represents an area dominated by one or more
major kinds of soil or miscellaneous areas. A map unit is identified and named
according to the taxonomic classification of the dominant soils. Within a taxonomic
class there are precisely defined limits for the properties of the soils. On the
landscape, however, the soils are natural phenomena, and they have the
characteristic variability of all natural phenomena. Thus, the range of some
observed properties may extend beyond the limits defined for a taxonomic class.
Areas of soils of a single taxonomic class rarely, if ever, can be mapped without
including areas of other taxonomic classes. Consequently, every map unit is made
up of the soils or miscellaneous areas for which it is named and some minor
components that belong to taxonomic classes other than those of the major soils.
Most minor soils have properties similar to those of the dominant soil or soils in the
map unit, and thus they do not affect use and management. These are called
noncontrasting, or similar, components. They may or may not be mentioned in a
particular map unit description. Other minor components, however, have properties
and behavioral characteristics divergent enough to affect use or to require different
management. These are called contrasting, or dissimilar, components. They
generally are in small areas and could not be mapped separately because of the
scale used. Some small areas of strongly contrasting soils or miscellaneous areas
are identified by a special symbol on the maps. If included in the database for a
given area, the contrasting minor components are identified in the map unit
descriptions along with some characteristics of each. A few areas of minor
components may not have been observed, and consequently they are not
mentioned in the descriptions, especially where the pattern was so complex that it
was impractical to make enough observations to identify all the soils and
miscellaneous areas on the landscape.
The presence of minor components in a map unit in no way diminishes the
usefulness or accuracy of the data. The objective of mapping is not to delineate
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
Custom Soil Resource Report
11
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
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.
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
Custom Soil Resource Report
13
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
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:
Custom Soil Resource Report
14
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)
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
Custom Soil Resource Report
15
References
American Association of State Highway and Transportation Officials (AASHTO).
2004. Standard specifications for transportation materials and methods of sampling
and testing. 24th edition.
American Society for Testing and Materials (ASTM). 2005. Standard classification of
soils for engineering purposes. ASTM Standard D2487-00.
Cowardin, L.M., V. Carter, F.C. Golet, and E.T. LaRoe. 1979. Classification of
wetlands and deep-water habitats of the United States. U.S. Fish and Wildlife
Service FWS/OBS-79/31.
Federal Register. July 13, 1994. Changes in hydric soils of the United States.
Federal Register. September 18, 2002. Hydric soils of the United States.
Hurt, G.W., and L.M. Vasilas, editors. Version 6.0, 2006. Field indicators of hydric
soils in the United States.
National Research Council. 1995. Wetlands: Characteristics and boundaries.
Soil Survey Division Staff. 1993. Soil survey manual. Soil Conservation Service.
U.S. Department of Agriculture Handbook 18. http://www.nrcs.usda.gov/wps/portal/
nrcs/detail/national/soils/?cid=nrcs142p2_054262
Soil Survey Staff. 1999. Soil taxonomy: A basic system of soil classification for
making and interpreting soil surveys. 2nd edition. Natural Resources Conservation
Service, U.S. Department of Agriculture Handbook 436. http://
www.nrcs.usda.gov/wps/portal/nrcs/detail/national/soils/?cid=nrcs142p2_053577
Soil Survey Staff. 2010. Keys to soil taxonomy. 11th edition. U.S. Department of
Agriculture, Natural Resources Conservation Service. http://
www.nrcs.usda.gov/wps/portal/nrcs/detail/national/soils/?cid=nrcs142p2_053580
Tiner, R.W., Jr. 1985. Wetlands of Delaware. U.S. Fish and Wildlife Service and
Delaware Department of Natural Resources and Environmental Control, Wetlands
Section.
United States Army Corps of Engineers, Environmental Laboratory. 1987. Corps of
Engineers wetlands delineation manual. Waterways Experiment Station Technical
Report Y-87-1.
United States Department of Agriculture, Natural Resources Conservation Service.
National forestry manual. http://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/
home/?cid=nrcs142p2_053374
United States Department of Agriculture, Natural Resources Conservation Service.
National range and pasture handbook. http://www.nrcs.usda.gov/wps/portal/nrcs/
detail/national/landuse/rangepasture/?cid=stelprdb1043084
16
United States Department of Agriculture, Natural Resources Conservation Service.
National soil survey handbook, title 430-VI. http://www.nrcs.usda.gov/wps/portal/
nrcs/detail/soils/scientists/?cid=nrcs142p2_054242
United States Department of Agriculture, Natural Resources Conservation Service.
2006. Land resource regions and major land resource areas of the United States,
the Caribbean, and the Pacific Basin. U.S. Department of Agriculture Handbook
296. http://www.nrcs.usda.gov/wps/portal/nrcs/detail/national/soils/?
cid=nrcs142p2_053624
United States Department of Agriculture, Soil Conservation Service. 1961. Land
capability classification. U.S. Department of Agriculture Handbook 210. http://
www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/nrcs142p2_052290.pdf
Custom Soil Resource Report
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APPENDIX C
Water Quality Computations, LID Information
Vault ID
Total
Required
WQ Volume
(cf)
InFlow,
WQ
(cfs)
Chamber
Type
Individual
Isolation
Chamber
Release
Rate
a
(cfs)
Individual
Isolation
Chamber
Volume
b
(cfs)
Individual
Installed
Isolation
Chamber
Volume
c
(cfs)
Mimimum
No. of
Chambers
d
Minimum
Release
Rate
(cfs)
e
Required
Isolation
Chamber
Volume by
FAA Method
(cf)
Provided
Number of
Isolation
Chambers
Provided
Isolation
Chamber
Release
Rate
e
(cfs)
Provided
Isolation
Chamber
Volume
Chamber Dimensions SC-160LP SC-310 SC-740
Width (in) 25 34.00 51.00
Length (in) 85.4 85.40 85.40
Height (in) 12 16.00 30.00
Floor Area (sf) 14.83 20.16 30.25
Chamber Volume (cf) 6.85 14.70 45.90
Chamber/Aggregate Volume (cf) 15.00 31.00 74.90
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-160LP SC-310 SC-740
Flow Rate/chamber (cfs) 0.011562 0.015724 0.023586
StormTech Chamber Data
Chamber Flow Rate Conversion (gpm/sf to cfs)
Chamber Flow Rate
D:\Projects\1252-005\Drainage\LID\1252-005_Vault Summary.xlsx
CHARACTER OF SURFACE:
Runoff
Coefficient
Percentage
Impervious Project: Union on Elizabeth
Streets, Parking Lots, Roofs, Alleys, and Drives: Calculations By: A. Reese
Asphalt ……....……………...……….....…...……………….………………………………….0.95 . 100% Date:
Concrete …….......……………….….……….………………..….………………………………… 0.95 90%
Gravel ……….…………………….….…………………………..……………………………….0.50 . 40%
Roofs …….…….………………..……………….…………………………………………….0.95 . 90%
Pavers…………………………...………………..…………………………………………….0.40 . 22%
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
(ac)
Area of
Asphalt
(ac)
Area of
Concrete
(ac)
Area of
Roofs
(ac)
Area of
Gravel
(ac)
Area of
Pavers (ac)
Area of
Lawns and
Landscaping
(ac)
2-year
Composite
Runoff
Coefficient
10-year
Composite
Runoff
Coefficient
100-year
Composite
Runoff
Coefficient
Composite
% Imperv.
1 0.19 0.00 0.13 0.00 0.00 0.00 0.07 0.71 0.71 0.89 59%
2 0.62 0.00 0.00 0.38 0.00 0.13 0.11 0.71 0.71 0.89 60%
3 1.04 0.00 0.00 1.04 0.00 0.00 0.00 0.95 0.95 1.00 90%
4 0.37 0.00 0.18 0.00 0.00 0.04 0.14 0.62 0.62 0.77 47%
Total 2.22 0.00 0.31 1.42 0.00 0.17 0.32 0.81 0.81 1.00 72%
DEVELOPED COMPOSITE % IMPERVIOUSNESS AND RUNOFF COEFFICIENT CALCULATIONS (LID TREATMENT)
Runoff Coefficients 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 1, 2017
Overland Flow, Time of Concentration:
Project: Union on Elizabeth
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)
2-yr
Tc
Rational Method Equation: Project: Union on Elizabeth
Calculations By:
Date:
From Section 3.2.1 of the CFCSDDC
Rainfall Intensity:
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)
Flow,
WQ
(cfs)
1 1 0.19 8 8 8 0.71 0.71 0.89 2.40 4.10 8.59 0.3 0.6 1.5 0.16
2 2 0.62 9 9 9 0.71 0.71 0.89 2.30 3.93 8.21 1.0 1.7 4.6 0.51
3 3 1.04 5 5 5 0.95 0.95 1.00 2.85 4.87 9.95 2.8 4.8 10.3 1.40
4 4 0.37 12 12 11 0.62 0.62 0.77 2.05 3.50 7.42 0.5 0.8 2.1 0.23
DEVELOPED RUNOFF COMPUTATIONS
A. Reese
November 1, 2017
Rainfall Intensity taken from the City of Fort Collins Storm Drainage Design Criteria (CFCSDDC), Figure 3.1
Q = C f ( C )( i )( A )
Union on Elizabeth
Fort Collins, Colorado
A. Reese Date: November 1, 2017
Pond No.: Vault 1
2
WQ
0.89
Area (A)= 0.62 acres Quantity Detention 176 ft
3
Max Release Rate = 0.32 cfs
Time Time
Ft.Collins
WQ
Intensity
Q100
Inflow
(Runoff)
Volume
Outflow
(Release) Volume
Storage
Detention
Volume
(mins) (secs) (in/hr) (cfs) (ft
3
) (ft
3
) (ft
3
)
5 300 1.43 0.8 236 96 140
10 600 1.11 0.6 366 192 174
15 900 0.94 0.5 464 288 176
20 1200 0.81 0.4 533 384 149
25 1500 0.72 0.4 592 480 112
30 1800 0.65 0.4 646 576 70
35 2100 0.59 0.3 678 672 6
40 2400 0.54 0.3 709 768 -59
45 2700 0.50 0.3 737 864 -127
50 3000 0.46 0.3 761 960 -199
55 3300 0.44 0.2 792 1056 -264
60 3600 0.41 0.2 814 1152 -338
65 3900 0.39 0.2 829 1248 -419
70 4200 0.37 0.2 846 1344 -498
75 4500 0.35 0.2 857 1440 -583
80 4800 0.33 0.2 874 1536 -662
85 5100 0.32 0.2 886 1632 -746
90 5400 0.31 0.2 909 1728 -819
95 5700 0.29 0.2 912 1824 -912
100 6000 0.28 0.2 927 1920 -993
105 6300 0.27 0.1 939 2016 -1077
110 6600 0.26 0.1 947 2112 -1165
115 6900 0.3 0.1 971 2208 -1237
120 7200 0.25 0.1 973 2304 -1331
Vault Volume Calculation | FAA Method
Project:
Project Location:
Calculations By:
Input Variables Results
Design Point
Sheet 1 of 2
Designer:
Company:
Date:
Project:
Location:
1. Basin Storage Volume
A) Effective Imperviousness of Tributary Area, Ia Ia = 90.0 %
(100% if all paved and roofed areas upstream of sand filter)
B) Tributary Area's Imperviousness Ratio (i = Ia/100) i = 0.900
C) Water Quality Capture Volume (WQCV) Based on 12-hour Drain Time WQCV = 0.36 watershed inches
WQCV= 0.9 * (0.91* i3 - 1.19 * i2 + 0.78 * i)
D) Contributing Watershed Area (including sand filter area) Area = 45,112 sq ft
E) Water Quality Capture Volume (WQCV) Design Volume VWQCV = 1,358 cu ft
VWQCV = 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 = cu ft
(Only if a different WQCV Design Volume is desired)
2. Basin Geometry
A) WQCV Depth DWQCV = 1.9 ft
B) Sand Filter Side Slopes (Horizontal distance per unit vertical, Z = 0.00 ft / ft
4:1 or flatter preferred). Use "0" if sand filter has vertical walls.
C) Mimimum Filter Area (Flat Surface Area) AMin = 302 sq ft
D) Actual Filter Area AActual = 975 sq ft
E) Volume Provided VT = 1466 cu ft
3. Filter Material
4. Underdrain System
A) Are underdrains provided?
B) Underdrain system orifice diameter for 12 hour drain time
i) Distance From Lowest Elevation of the Storage y = 1.8 ft
Volume to the Center of the Orifice
ii) Volume to Drain in 12 Hours Vol12 = 1,358 cu ft
iii) Orifice Diameter, 3/8" Minimum DO = 13 / 16 in
Union on Elizabeth
Fort Collins, CO
Design Procedure Form: Sand Filter (SF)
A. Reese
Northern Engineering
November 1, 2017
Choose One
Choose One
18" CDOT Class C Filter Material
Other (Explain):
YES
NO
Sand Filter_UD-BMP_v3.03.xlsm, SF 10/31/2017, 10:50 AM
WATER QUALITY CAPTURE VOLUME DESIGN CALCULATIONS
40-Hour Extended Detention (Concrete Vault)
Project: 1252-005
By: ATC
Date: 11/27/17
REQUIRED STORAGE & OUTLET WORKS:
BASIN AREA = 1.040 <-- INPUT from impervious calcs
BASIN IMPERVIOUSNESS PERCENT = 90.00 <-- INPUT from impervious calcs
BASIN IMPERVIOUSNESS RATIO = 0.9000 <-- CALCULATED
WQCV (watershed inches) = 0.401 <-- CALCULATED from USDCM Vol.3, Figure 3-2
WQCV (ac-ft) = 0.042 <-- CALCULATED from USDCM Vol.3, EQ 3-3
WQ Depth (ft) = 3.000 <-- INPUT from stage-storage table
AREA REQUIRED PER ROW, a (in2) = 0.127 <-- CALCULATED from Figure EDB-3
CIRCULAR PERFORATION SIZING:
dia (in) = 3/8 <-- INPUT from Figure 5
n = 9 <-- INPUT from Figure 5
t (in) = 1/4 <-- INPUT from Figure 5
number of rows = 1 <-- CALCULATED from WQ Depth and row spacing
APPENDIX D
Hydraulic Calculations
Channel Report
Hydraflow Express Extension for Autodesk® AutoCAD® Civil 3D® by Autodesk, Inc. Tuesday, Nov 28 2017
Sidewalk Cullvert-Basin 1 Outfall
Rectangular
Bottom Width (ft) = 2.00
Total Depth (ft) = 0.47
Invert Elev (ft) = 100.00
Slope (%) = 2.00
N-Value = 0.013
Calculations
Compute by: Known Q
Known Q (cfs) = 1.66
Highlighted
Depth (ft) = 0.18
Q (cfs) = 1.660
Area (sqft) = 0.36
Velocity (ft/s) = 4.61
Wetted Perim (ft) = 2.36
Crit Depth, Yc (ft) = 0.28
Top Width (ft) = 2.00
EGL (ft) = 0.51
0 .5 1 1.5 2 2.5 3
Elev (ft) Depth (ft)
Section
99.75 -0.25
100.00 0.00
100.25 0.25
100.50 0.50
100.75 0.75
101.00 1.00
Reach (ft)
Channel Report
Hydraflow Express Extension for Autodesk® AutoCAD® Civil 3D® by Autodesk, Inc. Tuesday, Nov 28 2017
Sidewalk Cullvert-Conc.Vault Outfall
Rectangular
Bottom Width (ft) = 2.00
Total Depth (ft) = 0.47
Invert Elev (ft) = 100.00
Slope (%) = 2.00
N-Value = 0.013
Calculations
Compute by: Known Q
Known Q (cfs) = 5.95
Highlighted
Depth (ft) = 0.42
Q (cfs) = 5.950
Area (sqft) = 0.84
Velocity (ft/s) = 7.08
Wetted Perim (ft) = 2.84
Crit Depth, Yc (ft) = 0.47
Top Width (ft) = 2.00
EGL (ft) = 1.20
0 .5 1 1.5 2 2.5 3
Elev (ft) Depth (ft)
Section
99.75 -0.25
100.00 0.00
100.25 0.25
100.50 0.50
100.75 0.75
101.00 1.00
Reach (ft)
Channel Report
Hydraflow Express Extension for Autodesk® AutoCAD® Civil 3D® by Autodesk, Inc. Monday, Nov 27 2017
<Name>
User-defined
Invert Elev (ft) = 28.90
Slope (%) = 0.50
N-Value = 0.018
Calculations
Compute by: Known Q
Known Q (cfs) = 27.92
(Sta, El, n)-(Sta, El, n)...
( 0.00, 29.75)-(6.00, 29.20, 0.016)-(24.50, 29.00, 0.016)-(25.50, 28.90, 0.016)-(26.00, 29.30, 0.016)-(34.00, 30.00, 0.035)
Highlighted
Depth (ft) = 0.63
Q (cfs) = 27.92
Area (sqft) = 9.65
Velocity (ft/s) = 2.89
Wetted Perim (ft) = 26.40
Crit Depth, Yc (ft) = 0.59
Top Width (ft) = 26.23
EGL (ft) = 0.76
-5 0 5 10 15 20 25 30 35 40
Elev (ft) Depth (ft)
Section
28.00 -0.90
28.50 -0.40
29.00 0.10
29.50 0.60
30.00 1.10
30.50 1.60
31.00 2.10
Sta (ft)
Hydraflow Plan View
Project File: Storm_Outfall.stm No. Lines: 4 10-24-2017
Hydraflow Storm Sewers 2005
Hydraulic Grade Line Computations Page 1
Line Size Q Downstream Len Upstream Check JL Minor
coeff loss
Invert HGL Depth Area Vel Vel EGL Sf Invert HGL Depth Area Vel Vel EGL Sf Ave Enrgy
elev elev head elev elev elev head elev Sf loss
(in) (cfs) (ft) (ft) (ft) (sqft) (ft/s) (ft) (ft) (%) (ft) (ft) (ft) (ft) (sqft) (ft/s) (ft) (ft) (%) (%) (ft) (K) (ft)
1 15 7.40 5028.30 5029.39 1.09 1.13 6.54 0.66 5030.05 1.200 28.8 5028.36 5029.85 1.25 1.23 6.03 0.57 5030.41 1.313 1.257 0.362 0.69 0.39
2 15 7.40 5028.36 5030.24 1.25 1.23 6.03 0.57 5030.80 1.314 25.6 5028.41 5030.57 1.25 1.23 6.03 0.57 5031.14 1.313 1.314 0.336 1.00 0.57
3 15 5.20 5028.41 5031.43 1.25 1.23 4.24 0.28 5031.70 0.649 74.6 5028.56 5031.91 1.25 1.23 4.24 0.28 5032.19 0.648 0.649 0.484 1.00 0.28
4 15 5.20 5028.56 5032.19 1.25 1.23 4.24 0.28 5032.47 0.649 4.2 5028.57 5032.22 1.25 1.23 4.24 0.28 5032.50 0.648 0.649 0.027 1.00 0.28
Project File: Storm_Outfall.stm Number of lines: 4 Run Date: 10-24-2017
Hydraflow Storm Sewers 2005
APPENDIX E
Detention Calculations
ATC
Pond No : Concrete Vault
3
100-yr
1.00
Area (A)= 1.04 acres 1697 ft3
Max Release Rate = 5.20 cfs 0.039 ac-ft
Time Time
100-yr
Intensity
Q100
Inflow
(Runoff)
Volume
Outflow
(Release)
Volume
Storage
Detention
Volume
(mins) (secs) (in/hr) (cfs) (ft3) (ft3) (ft3)
5 300 9.950 10.35 3104 1560.0 1544.4
10 600 7.720 8.03 4817 3120.0 1697.3
15 900 6.520 6.78 6103 4680.0 1422.7
20 1200 5.600 5.82 6989 6240.0 748.8
25 1500 4.980 5.18 7769 7800.0 -31.2
30 1800 4.520 4.70 8461 9360.0 -898.6
35 2100 4.080 4.24 8911 10920.0 -2009.3
40 2400 3.740 3.89 9335 12480.0 -3145.0
45 2700 3.460 3.60 9716 14040.0 -4324.3
50 3000 3.230 3.36 10078 15600.0 -5522.4
55 3300 3.030 3.15 10399 17160.0 -6761.0
60 3600 2.860 2.97 10708 18720.0 -8012.2
65 3900 2.720 2.83 11032 20280.0 -9247.7
70 4200 2.590 2.69 11313 21840.0 -10526.9
75 4500 2.480 2.58 11606 23400.0 -11793.6
80 4800 2.380 2.48 11881 24960.0 -13079.0
85 5100 2.290 2.38 12146 26520.0 -14373.8
90 5400 2.210 2.30 12411 28080.0 -15668.6
95 5700 2.130 2.22 12627 29640.0 -17013.4
100 6000 2.060 2.14 12854 31200.0 -18345.6
105 6300 2.000 2.08 13104 32760.0 -19656.0
110 6600 1.940 2.02 13316 34320.0 -21003.8
115 6900 1.890 1.97 13563 35880.0 -22317.4
120 7200 1.840 1.91 13778 37440.0 -23662.1
DETENTION POND CALCULATION; FAA METHOD
Project Number : 1252-005
Date : 11-27-17
Project Location : Fort Collins
Developed "C" =
1.35
Calculations By:
Input Variables Results
Design Point
Design Storm Required Detention Volume
OUTLET RATING CURVE
Concrete Vault Detention Orifice
Project: 1252-005
Date: 10/15/2017
By: ATC
100-YR ORIFICE RATING
Orifice Dia (in) 9.50
Orifice Area (sf) 0.4922
Orifice invert (ft) 0.00
Orifice Coefficient 0.65
Outlet
Orifice Area Stage release
(SF) (FT) (CFS)
0.4922 0.00 0.00
0.4922 0.25 1.28
0.4922 0.50 1.82
0.4922 0.75 2.22
0.4922 1.00 2.57
0.4922 1.25 2.87
0.4922 1.50 3.14
0.4922 1.75 3.40
0.4922 2.00 3.63
0.4922 2.25 3.85
0.4922 2.50 4.06
0.4922 2.75 4.26
0.4922 3.00 4.45
0.4922 3.25 4.63
0.4922 3.50 4.80
0.4922 3.75 4.97
0.4922 4.00 5.14
ATC
Pond No : Paver Subgrade (Chamber System)
2
100-yr
0.92
Area (A)= 0.62 acres 3320 ft3
Max Release Rate = 0.75 cfs 0.076 ac-ft
Time Time
100-yr
Intensity
Q100
Inflow
(Runoff)
Volume
Outflow
(Release)
Volume
Storage
Detention
Volume
(mins) (secs) (in/hr) (cfs) (ft3) (ft3) (ft3)
5 300 9.950 5.68 1703 225.0 1477.6
10 600 7.720 4.40 2642 450.0 2192.1
15 900 6.520 3.72 3347 675.0 2672.1
20 1200 5.600 3.19 3833 900.0 2933.1
25 1500 4.980 2.84 4261 1125.0 3135.9
30 1800 4.520 2.58 4641 1350.0 3290.8
35 2100 4.080 2.33 4887 1575.0 3312.2
40 2400 3.740 2.13 5120 1800.0 3319.9
45 2700 3.460 1.97 5329 2025.0 3303.7
50 3000 3.230 1.84 5527 2250.0 3277.2
55 3300 3.030 1.73 5703 2475.0 3228.4
60 3600 2.860 1.63 5873 2700.0 3172.8
65 3900 2.720 1.55 6051 2925.0 3125.8
70 4200 2.590 1.48 6205 3150.0 3054.8
75 4500 2.480 1.41 6366 3375.0 2990.7
80 4800 2.380 1.36 6516 3600.0 2916.2
85 5100 2.290 1.31 6662 3825.0 2836.7
90 5400 2.210 1.26 6807 4050.0 2757.2
95 5700 2.130 1.21 6925 4275.0 2650.2
100 6000 2.060 1.18 7050 4500.0 2550.1
105 6300 2.000 1.14 7187 4725.0 2462.0
110 6600 1.940 1.11 7303 4950.0 2353.4
115 6900 1.890 1.08 7439 5175.0 2263.6
120 7200 1.840 1.05 7557 5400.0 2156.7
DETENTION POND CALCULATION; FAA METHOD
Project Number : 1252-005
Date : 11-27-17
1.35
Design Point
Design Storm Required Detention Volume
Developed "C" =
Project Location : Fort Collins
Input Variables Results
Calculations By:
OUTLET RATING CURVE
Pavers Subgrade Detention Orifice
Project: 1252-005
Date: 10/15/2017
By: ATC
100-YR ORIFICE RATING
Orifice Dia (in) 4.25
Orifice Area (sf) 0.0985
Orifice invert (ft) 0.00
Orifice Coefficient 0.65
Outlet
Orifice Area Stage release
(SF) (FT) (CFS)
0.0985 0.00 0.00
0.0985 0.25 0.26
0.0985 0.50 0.36
0.0985 0.75 0.45
0.0985 1.00 0.51
0.0985 1.25 0.57
0.0985 1.50 0.63
0.0985 1.75 0.68
0.0985 2.00 0.73
Channel Report
Hydraflow Express Extension for Autodesk® AutoCAD® Civil 3D® by Autodesk, Inc. Monday, Nov 27 2017
<Name>
Rectangular
Bottom Width (ft) = 30.70
Total Depth (ft) = 0.50
Invert Elev (ft) = 29.50
Slope (%) = 0.20
N-Value = 0.016
Calculations
Compute by: Known Q
Known Q (cfs) = 17.04
Highlighted
Depth (ft) = 0.31
Q (cfs) = 17.04
Area (sqft) = 9.52
Velocity (ft/s) = 1.79
Wetted Perim (ft) = 31.32
Crit Depth, Yc (ft) = 0.22
Top Width (ft) = 30.70
EGL (ft) = 0.36
0 5 10 15 20 25 30 35 40 45
Elev (ft) Depth (ft)
Section
29.00 -0.50
29.50 0.00
30.00 0.50
30.50 1.00
31.00 1.50
Reach (ft)
Sharp-Crested Weir:
Project: 1252-005
By: ATC
Date: 10/31/17
Governing Equations:
Q=3.3LH 1.5
* where Q is flow rate in CFS
* where L is the crest length of the weir (FT)
* where H is the height of flow over the crest (FT)
Input Parameters:
Length (L)= 29.50 FT
Crest Elevation = 5034.10 FT
Depth vs. Flow:
Depth Above
Crest (ft)
Elevation
(ft)
Flow
(cfs)
0.00 5034.10 0.00
0.10 5034.20 3.08
0.20 5034.30 8.71
0.22 5034.32 10.32 Q100
0.40 5034.50 24.63
0.50 5034.60 34.42
Q100 = 10.3 CFS (Max inflow from Basin 3)
This equation can be used to derive the stage-discharge relationship for a sharp crested weir where the depth of flow is small
compared to the length of weir. Reference 1) Hydrologic Analysis and Design, Richard H McCuen, Prentice Hall, 1989.
Pg.549.
Stormwater Facility Name:
Facility Location & Jurisdiction:
User (Input) Watershed Characteristics User Defined User Defined User Defined User Defined
Watershed Slope = 0.015 ft/ft Stage [ft] Area [ft^2] Stage [ft] Discharge [cfs]
Watershed Length-to-Width Ratio = 1.10 L:W 0.00 0 0.00 0.00
Watershed Area = 0.97 acres 2.00 1,205 2.00 3.60
Watershed Imperviousness = 90.0% percent 3.00 1,206 3.00 4.50
Percentage Hydrologic Soil Group A = percent 4.00 1,207 4.00 5.20
Percentage Hydrologic Soil Group B = percent
Percentage Hydrologic Soil Groups C/D = 100.0% percent
User Input: Detention Basin Characteristics
WQCV Design Drain Time = 40.00 hours
After completing and printing this worksheet to a pdf, go to:
https://maperture.digitaldataservices.com/gvh/?viewer=cswdif,
create a new stormwater facility, and
attach the pdf of this worksheet to that record.
Routed Hydrograph Results
Design Storm Return Period = WQCV 2 Year 5 Year 10 Year 25 Year 50 Year 100 Year
Two-Hour Rainfall Depth = 0.53 0.98 1.36 1.71 2.31 2.91 3.67 in
Calculated Runoff Volume = 0.032 0.071 0.102 0.131 0.182 0.233 0.300 acre-ft
OPTIONAL Override Runoff Volume = acre-ft
Inflow Hydrograph Volume = 0.032 0.070 0.101 0.131 0.182 0.233 0.299 acre-ft
Time to Drain 97% of Inflow Volume = 1 1 1 1 1 1 1 hours
Time to Drain 99% of Inflow Volume = 1 1 1 1 1 1 1 hours
Maximum Ponding Depth = 0.45 0.90 1.24 1.53 1.99 2.57 3.41 ft
Maximum Ponded Area = 0.006 0.012 0.017 0.021 0.027 0.028 0.028 acres
Maximum Volume Stored = 0.001 0.006 0.011 0.016 0.027 0.043 0.066 acre-ft
Stormwater Detention and Infiltration Design Data Sheet
Project #:1252-005
Concrete Vault Detention
Workbook Protected Worksheet Protected
Stormwater Detention and Infiltration Design CRS Spdsht-ConcVault.xlsm, Design Data 10/24/2017, 2:51 PM
Doing_Clear_Formatting Yes =
CountA= 1
0 1 2 3
#N/A
#N/A
0 1 2 3
#N/A
#N/A
Check Data Set 1 Check Data Set 1
Stormwater Detention and Infiltration Design Data Sheet
Area
Discharge
0
1
2
3
4
5
6
7
8
9
0.1 1 10
FLOW [cfs]
TIME [hr]
100YR IN
100YR OUT
50YR IN
50YR OUT
25YR IN
25YR OUT
10YR IN
10YR OUT
5YR IN
5YR OUT
2YR IN
2YR OUT
WQCV IN
WQCV OUT
0
0.5
1
1.5
2
2.5
3
3.5
4
0.1 1 10 100
PONDING DEPTH [ft]
DRAIN TIME [hr]
100YR
50YR
25YR
10YR
5YR
2YR
WQCV
Stormwater Detention and Infiltration Design CRS Spdsht-ConcVault.xlsm, Design Data 10/24/2017, 2:51 PM
Stormwater Facility Name:
Facility Location & Jurisdiction:
User (Input) Watershed Characteristics User Defined User Defined User Defined User Defined
Watershed Slope = 0.008 ft/ft Stage [ft] Area [ft^2] Stage [ft] Discharge [cfs]
Watershed Length-to-Width Ratio = 2.80 L:W 0.00 0 0.00 0.00
Watershed Area = 0.61 acres 0.75 5,136 0.75 0.45
Watershed Imperviousness = 64.9% percent 1.50 5,137 1.50 0.63
Percentage Hydrologic Soil Group A = 0.0% percent 2.00 5,138 2.00 0.73
Percentage Hydrologic Soil Group B = 0.0% percent
Percentage Hydrologic Soil Groups C/D = 100.0% percent
User Input: Detention Basin Characteristics
WQCV Design Drain Time = 12.00 hours
After completing and printing this worksheet to a pdf, go to:
https://maperture.digitaldataservices.com/gvh/?viewer=cswdif,
create a new stormwater facility, and
attach the pdf of this worksheet to that record.
Routed Hydrograph Results
Design Storm Return Period = WQCV 2 Year 5 Year 10 Year 25 Year 50 Year 100 Year
Two-Hour Rainfall Depth = 0.53 0.98 1.36 1.71 2.31 2.91 3.67 in
Calculated Runoff Volume = 0.010 0.031 0.049 0.066 0.097 0.127 0.167 acre-ft
OPTIONAL Override Runoff Volume = acre-ft
Inflow Hydrograph Volume = 0.010 0.031 0.049 0.066 0.097 0.127 0.167 acre-ft
Time to Drain 97% of Inflow Volume = 2 2 3 3 4 4 5 hours
Time to Drain 99% of Inflow Volume = 2 3 3 3 4 5 5 hours
Maximum Ponding Depth = 0.18 0.40 0.53 0.65 0.83 1.01 1.28 ft
Maximum Ponded Area = 0.028 0.062 0.083 0.102 0.118 0.118 0.118 acres
Maximum Volume Stored = 0.002 0.012 0.022 0.033 0.053 0.075 0.106 acre-ft
Stormwater Detention and Infiltration Design Data Sheet
Project #:1252-005
Paver Detention (Chamber System)
Workbook Protected Worksheet Protected
Stormwater Detention and Infiltration Design CRS Spdsht-Pavers.xlsm, Design Data 11/28/2017, 1:30 PM
Doing_Clear_Formatting Yes =
CountA= 1
0 1 2 3
#N/A
#N/A
0 1 2 3
#N/A
#N/A
Check Data Set 1 Check Data Set 1
Stormwater Detention and Infiltration Design Data Sheet
Area
Discharge
0
0.5
1
1.5
2
2.5
3
3.5
0.1 1 10
FLOW [cfs]
TIME [hr]
100YR IN
100YR OUT
50YR IN
50YR OUT
25YR IN
25YR OUT
10YR IN
10YR OUT
5YR IN
5YR OUT
2YR IN
2YR OUT
WQCV IN
WQCV OUT
0
0.2
0.4
0.6
0.8
1
1.2
1.4
0.1 1 10 100
PONDING DEPTH [ft]
DRAIN TIME [hr]
100YR
50YR
25YR
10YR
5YR
2YR
WQCV
Stormwater Detention and Infiltration Design CRS Spdsht-Pavers.xlsm, Design Data 11/28/2017, 1:30 PM
APPENDIX F
Erosion Control Report
Union on Elizabeth
Final Erosion Control Report
EROSION CONTROL REPORT
A comprehensive Erosion and Sediment Control Plan (along with associated details) has been
included with the final construction drawings. It should be noted, however, that any such Erosion
and Sediment Control Plan serves only as a general guide to the Contractor. Staging and/or phasing
of the BMPs depicted, and additional or different BMPs from those included may be necessary
during construction, or as required by the authorities having jurisdiction.
It shall be the responsibility of the Contractor to ensure erosion control measures are properly
maintained and followed. The Erosion and Sediment Control Plan is intended to be a living
document, constantly adapting to site conditions and needs. The Contractor shall update the
location of BMPs as they are installed, removed or modified in conjunction with construction
activities. It is imperative to appropriately reflect the current site conditions at all times.
The Erosion and Sediment Control Plan shall address both temporary measures to be implemented
during construction, as well as permanent erosion control protection. Best Management Practices
from the Volume 3, Chapter 7 – Construction BMPs will be utilized. Measures may include, but are
not limited to, silt fencing along the disturbed perimeter, gutter protection in the adjacent roadways
and inlet protection at existing and proposed storm inlets. Vehicle tracking control pads, spill
containment and clean-up procedures, designated concrete washout areas, dumpsters, and job site
restrooms shall also be provided by the Contractor.
Grading and Erosion Control Notes can be found on the Utility Plans. The Final Plan set contains a
full-size Erosion Control sheet as well as a separate sheet dedicated to Erosion Control Details. In
addition to this report and the referenced plan sheets, the Contractor shall be aware of, and adhere
to, the applicable requirements outlined in the Development Agreement for the development. Also,
the Site Contractor for this project will be required to secure a Stormwater Construction General
Permit from the Colorado Department of Public Health and Environment (CDPHE), Water Quality
Control Division – Stormwater Program, prior to any earth disturbance activities. Prior to securing
said permit, the Site Contractor shall develop a comprehensive StormWater Management Plan
(SWMP) pursuant to CDPHE requirements and guidelines. The SWMP will further describe and
document the ongoing activities, inspections, and maintenance of construction BMPs.
APPENDIX G
Current Effective FIRM Panel
MAP POCKET
Drainage Exhibit
DS
DS
DS
DS
DS
DS
FDC
TF
TF TF
TF
VAULT
F.O.
FO
T
T
CABLE
X X
X
X
X
X X
X X
X X X X X
X
t
t
X X X X
T
T T
T T
T T T
T
T
D
X
TF
X
SD
UD UD UD UD UD UD UD UD
SD
UD UD UD UD UD UD UD UD
1
2
3
4
LOT 3, CAMPUS WEST
SHOPPING CENTER
COLLINS CAMPUS
WEST LLC
1110 W ELIZABETH ST
LOT 1, CAMPUS WEST
SHOPPING CENTER
NCIC LLC
1232 W ELIZABETH ST
TOWN SQUARE
CONDOMINIUMS
LOKAL FORT
COLLINS CO LLC
1201 W PLUM ST
CAMBRIDGE HOUSE LOFTS
X
TF
X
W W W W W W W
VAULT
F.O.
FO
T
T
CABLE
CTV
T
E
E
E E E
E E E
t
t
T
T T
T T
T T T
T
T
D
DS
DS
DS
DS
DS
DS
FDC
TF
TF
TF
TF
SD
UD UD UD UD UD UD UD UD
SD
UD UD UD UD UD UD UD UD
5028 (NAVD88)
5029 (NAVD88)
1227
1319
1538
1411
1059
FFE=30.90
FFE=30.90
FFE=30.90
FFE=30.90
FFE=31.40
FFE=32.90
FFE=32.90 FFE=32.90
FFE=30.93
FFE=31.40
FFE=31.40
LOT 3, CAMPUS WEST
SHOPPING CENTER
COLLINS CAMPUS
WEST LLC
1110 W ELIZABETH ST
LOT 1, CAMPUS WEST
SHOPPING CENTER
NCIC LLC
1232 W ELIZABETH ST
TOWN SQUARE
CONDOMINIUMS
LOKAL
FORT COLLINS CO LLC
1201 W PLUM ST
CAMBRIDGE HOUSE LOFTS
BRIDGE-CAMBRIDGE LP
1113 W PLUM ST
LOT 1, SOUTH SHIELDS
SUBDIVISION
825 S SHIELDS LLC
825 S SHIELDS ST
WEST ELIZABETH STREET
(80' ROW)
INTERPOLATED CSL
5029.30 (NAVD88)
FFE=30.90
1172
INTERPOLATED CSL
5028.80 (NAVD88)
5027 (NAVD88)
FFE=32.90
FFE=31.40
32.70
EXISTING 100-YR
FLOODPLAIN
(PER CSU CLOMR)
EXISTING 100-YR FLOODWAY
(PER CSU CLOMR)
EXISTING 100-YR FLOODWAY
(PER CSU CLOMR)
EXISTING 100-YR
FLOODPLAIN
(PER CSU CLOMR)
NORTHERN ENGINEERING
PROJECT NO. 1252-006
DATE: APRIL 2017
PLS GROUP
PROJECT NO. 16066.002
DATE: MAY 2017
City Engineer Date
Date
Date
Date
Date
Stormwater Utility
Parks & Recreation
Traffic Engineer Date
APPROVED:
CHECKED BY:
CHECKED BY:
CHECKED BY:
CHECKED BY:
CHECKED BY:
Water & Wastewater Utility
City of Fort Collins, Colorado
UTILITY PLAN APPROVAL
Environmental Planner
C800
FLOODPLAIN EXHIBIT
A. Reese
B. Ruch
1"=20'
FOR DRAINAGE REVIEW ONLY
NOT FOR CONSTRUCTION
NORTH
( IN FEET )
1 inch = ft.
20 0 20 Feet
20
40 60
No. Revisions:
By: Date:
REVIEWED BY:
N. Haws
DESIGNED BY:
DRAWN BY:
SCALE:
DATE:
DEC. 27, 2017
PROJECT:
1252-005
Sheet
UNION ON ELIZABETH
These drawings are
instruments of service
provided by Northern
Engineering Services, Inc.
and are not to be used for
any type of construction
unless signed and sealed by
a Professional Engineer in
the employ of Northern
Engineering Services, Inc.
NOT FOR CONSTRUCTION
REVIEW SET
12/27/17
E N G I N E E R I N G
N O R T H E RN
FORT COLLINS: 301 North Howes Street, Suite 100, 80521
GREELEY: 820 8th Street, 80631
970.221.4158
northernengineering.com
19 of 19
LEGEND:
PROPOSED CONTOUR
EXISTING STORM SEWER
PROPOSED STORM SEWER
PROPOSED SWALE
EXISTING CONTOUR
PROPOSED CURB & GUTTER
PROPOSED STORM INLET
PROPOSED CONCRETE
CROSS PAN (TYP.)
PEDESTRIAN ACCESS RAMPS
PROPERTY BOUNDARY
CROSS-SECTION (CSU CLOMR) XS#: 2446
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 CITY-REGULATED OLD TOWN 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 THE CITY OF
FORT COLLINS VERTICAL CONTROL DATUM (NAVD 88).
4. ANY ITEMS LOCATED IN THE FLOODWAY THAT CAN FLOAT (E.G., PICNIC TABLES, BIKE RACKS, ETC.)
MUST BE ANCHORED.
5. A FLOODPLAIN USE PERMIT SHALL BE REQUIRED FOR EACH SITE CONSTRUCTION ELEMENT IN THE
FLOODPLAIN, INCLUDING BUILDING. THE FLOODPLAIN USE PERMIT FOR THE BUILDING WILL BE
APPROVED AT THE TIME OF BUILDING PERMIT APPLICATION.
6. 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.
7. REFER TO THE FINAL DRAINAGE REPORT FOR UNION ON ELIZABETH, DATED DECEMBER 27, 2017
FOR ADDITIONAL INFORMATION.
8. A FLOODPLAIN USE PERMIT AND NO RISE CERTIFICATION IS REQUIRED PRIOR TO PERFORMING ANY
WORK WITHIN THE FLOODWAY (I.E., CURB CUT REMOVAL, LANDSCAPING).
9. A POST-CONSTRUCTION ELEVATION CERTIFICATE MUST BE APPROVED BEFORE A CERTIFICATE OF
OCCUPANCY WILL BE ISSUED.
10. ALL HVAC EQUIPMENT IS TO BE PLACED AT OR ABOVE THE REGULATORY FLOOD PROTECTION
ELEVATION.
11. HORIZONTAL CONTROL: CITY OF FORT COLLINS GROUND MASTER CONTROL.
FIELD SURVEY BY:
BENCHMARKS:
5013
PROJECT DATUM: NAVD88
CITY OF FORT COLLINS BENCHMARK 20-97
AT THE SOUTHWEST CORNER OF WEST ELIZABETH AND CONSTITUTION AVE. ON A
CONCRETE TRAFFIC SIGNAL BASE.
ELEV.=5050.15
CITY OF FORT COLLINS BENCHMARK 19-97
AT THE SOUTHEAST CORNER OF WEST ELIZABETH AND SHIELDS ST., ON A CONCRETE
TRAFFIC SIGNAL BASE.
ELEV.=5025.74
PLEASE NOTE: THIS PLAN SET IS USING NAVD88 FOR A VERTICAL DATUM. SURROUNDING
DEVELOPMENTS HAVE USED NGVD29 UNADJUSTED FOR THEIR VERTICAL DATUMS.
IF NGVD29 UNADJUSTED DATUM IS REQUIRED FOR ANY PURPOSE, THE FOLLOWING
EQUATION SHOULD BE USED:
NGVD29 UNADJUSTED = NAVD88 - 3.18'
BASIS OF BEARINGS
THE BASIS OF BEARINGS IS THE SOUTH LINE OF LOT 3 AS BEARING NORTH 89°09'38" WEST.
MINIMUM FINISHED FLOOR ELEVATION
(FFE) = C (FFE VARIES, SEE PLAN)
BASE FLOOD ELEVATION
(BFE) = A
MINIMUM HVAC EQUIPMENT
ELEVATION = B
BASE FLOOD ELEVATION
(BFE) = A
18"
MIN.
HVAC
UNIT
DETAIL
NTS
SLAB-ON-GRADE
MIXED-USE BUILDING
SUMMARY - WEST
BUILDING
ELEV. DESIGNATION
PROJECT ELEV.
(NAVD 88)
A 5029.30 FT
B 5030.80 FT
C 5030.80 FT
REGULATORY FLOOD
PROTECTION
ELEVATION
5030.80 FT
BASE FLOOD ELEVATION (CSU CLOMR)
ELEVATION NGVD 88 5000
MIXED-USE BUILDING
SUMMARY - EAST
BUILDING
ELEV. DESIGNATION
PROJECT ELEV.
(NAVD 88)
A 5028.80 FT
B 5030.30 FT
C 5030.30 FT
REGULATORY FLOOD
PROTECTION
ELEVATION
5030.30 FT
EXISTING 100-YR FLOODPLAIN
(PER CSU CLOMR)
EXISTING 100-YR FLOODWAY
(PER CSU CLOMR)
BRIDGE-CAMBRIDGE LP
1113 W PLUM ST
LOT 1, SOUTH SHIELDS
SUBDIVISION
825 S SHIELDS LLC
825 S SHIELDS ST
WEST ELIZABETH STREET
(80' ROW)
OS1
OS2
VAULT AREA
SAND FILTER AREA
1
0.19
2
0.62 3
1.04
4
0.37
OS1
2.95
OS2
0.22
PROPOSED 2'
SIDEWALK CULVERT
PROPOSED 2'
SIDEWALK CULVERT EXISTING 2'
SIDEWALK CHASE
PROPOSED
TRENCH DRAIN
PROPOSED
OUTLET STRUCTURE
PROPOSED 2'
CONCRETE PAN
EXISTING 24" RCP STORM DRAIN
SEE DRAINAGE REPORT FOR
HISTORIC DRAINAGE EXHIBIT
SHOWING OFFSITE BASIN DELINEATION
SEE DRAINAGE REPORT FOR
HISTORIC DRAINAGE EXHIBIT
SHOWING OFFSITE BASIN DELINEATION
PROPOSED 4'
CONCRETE PAN
PROPOSED
TRENCH DRAIN
PROPOSED
STORM DRAIN
PROPOSED
STORM DRAIN
PROPOSED 4'
CONCRETE PAN
PROPOSED 2'
CONCRETE PAN
PROPOSED 2'
CURB CUT
PROPOSED 2'
SIDEWALK CHASE
PROPOSED 2'
SIDEWALK CHASE
PROPOSED
TRENCH DRAIN
PROPOSED
TRENCH DRAIN
PROPOSED 2'
CURB CUT
TIE TO EXISTING
PAN FLOWLINE
PROPOSED 2'
CONCRETE PAN
EXISTING 100-YR
FLOODPLAIN
(PER CSU CLOMR)
EXISTING 100-YR
FLOODWAY
(PER CSU
CLOMR)
EXISTING 100-YR
FLOODPLAIN
(PER CSU CLOMR)
EXISTING 100-YR
FLOODPLAIN
(PER CSU CLOMR)
CALL 2 BUSINESS DAYS IN ADVANCE BEFORE YOU
DIG, GRADE, OR EXCAVATE FOR THE MARKING OF
UNDERGROUND MEMBER UTILITIES.
CALL UTILITY NOTIFICATION CENTER OF
COLORADO
Know what'sbelow.
Call before you dig.
R
City Engineer Date
Date
Date
Date
Date
Stormwater Utility
Parks & Recreation
Traffic Engineer Date
APPROVED:
CHECKED BY:
CHECKED BY:
CHECKED BY:
CHECKED BY:
CHECKED BY:
Water & Wastewater Utility
City of Fort Collins, Colorado
UTILITY PLAN APPROVAL
Environmental Planner
C700
DRAINAGE EXHIBIT
A. Reese
B. Ruch
1"=20'
NORTH
( IN FEET )
1 inch = ft.
20 0 20 Feet
20
40 60
No. Revisions:
By: Date:
REVIEWED BY:
N. Haws
DESIGNED BY:
DRAWN BY:
SCALE:
DATE:
DEC. 27, 2017
PROJECT:
1252-005
Sheet
UNION ON ELIZABETH
These drawings are
instruments of service
provided by Northern
Engineering Services, Inc.
and are not to be used for
any type of construction
unless signed and sealed by
a Professional Engineer in
the employ of Northern
Engineering Services, Inc.
NOT FOR CONSTRUCTION
REVIEW SET
12/27/17
E N G I N E E R I N G
N O R T H E RN
FORT COLLINS: 301 North Howes Street, Suite 100, 80521
GREELEY: 820 8th Street, 80631
970.221.4158
northernengineering.com
18 of 19
LEGEND:
4953
PROPOSED CONTOUR
PROPOSED STORM SEWER
PROPOSED SWALE
EXISTING CONTOUR
PROPOSED CURB & GUTTER
PROPERTY BOUNDARY
PROPOSED INLET
DESIGN POINT A
FLOW ARROW
DRAINAGE BASIN LABEL
DRAINAGE BASIN BOUNDARY
PROPOSED SWALE SECTION
1 1
NOTES:
1. REFER TO THE FINAL DRAINAGE REPORT FOR UNION ON ELIZABETH, DATED DECEMBER 27, 2017 FOR
ADDITIONAL INFORMATION.
BASIN
DESIGNATION
AREA BASIN (AC)
BENCHMARK
FOR DRAINAGE REVIEW ONLY
NOT FOR CONSTRUCTION
C
0.60 ac
PROJECT DATUM: NAVD88
CITY OF FORT COLLINS BENCHMARK 20-97
AT THE SOUTHWEST CORNER OF WEST ELIZABETH AND CONSTITUTION AVE. ON A CONCRETE TRAFFIC
SIGNAL BASE.
ELEV.=5050.15
CITY OF FORT COLLINS BENCHMARK 19-97
AT THE SOUTHEAST CORNER OF WEST ELIZABETH AND SHIELDS ST., ON A CONCRETE TRAFFIC SIGNAL
BASE.
ELEV.=5025.74
PLEASE NOTE: THIS PLAN SET IS USING NAVD88 FOR A VERTICAL DATUM. SURROUNDING DEVELOPMENTS
HAVE USED NGVD29 UNADJUSTED FOR THEIR VERTICAL DATUMS.
IF NGVD29 UNADJUSTED DATUM IS REQUIRED FOR ANY PURPOSE, THE FOLLOWING EQUATION SHOULD BE
USED:
NGVD29 UNADJUSTED = NAVD88 - 3.18'
BASIS OF BEARINGS
THE BASIS OF BEARINGS IS THE SOUTH LINE OF LOT 3 AS BEARING NORTH 89°09'38" WEST.
DRAINAGE SUMMARY TABLE
DESIGN
POINT
BASIN
ID
TOTAL
AREA
(acres)
C2 C100
2-yr
Tc
(min)
100-yr
Tc
(min)
Q2
(cfs)
Q100
(cfs)
1 1 0.19 0.71 1.00 8.4 7.9 0.33 1.66
2 2 0.62 0.73 0.92 9.3 8.8 1.05 4.69
3 3 1.04 0.95 1.00 5.0 5.0 2.80 10.30
4 4 0.37 0.63 0.79 12.1 11.4 0.47 2.15
Design Storm Required Detention Volume
Developed "C" =
D:\Projects\1252-005\Drainage\LID\1252-005_FAA_Vault 1.xlsm\
(min)
10-yr
Tc
(min)
100-yr
Tc
(min)
1 1 No 0.25 0.25 0.31 22 2.00% 5.9 5.9 5.5 207 0.50% 1.41 2.4 0 n/a N/A N/A 8 8 8
2 2 No 0.25 0.25 0.31 35 2.00% 7.5 7.5 6.9 160 0.50% 1.41 1.9 0 n/a N/A N/A 9 9 9
3 3 No 0.90 0.90 1.00 55 0.50% 3.5 3.5 1.7 50 0.50% 1.41 0.6 0 n/a N/A N/A 5 5 5
4 4 No 0.25 0.25 0.31 43 1.30% 9.6 9.6 8.8 215 0.50% 1.41 2.5 0 n/a N/A N/A 12 12 11
DEVELOPED TIME OF CONCENTRATION COMPUTATIONS
Gutter Flow Swale Flow
Design
Point
Basin
Overland Flow
A. Reese
November 1, 2017
Time of Concentration
(Equation RO-4)
( )
3
1
1 . 87 1 . 1 *
S
Ti C Cf L
-
=
f
(cf)
Total
Installed
Chamber
Volume
g
(cf)
1 N/A 0.51 SC-160LP 0.012 6.85 15.00 N/A N/A 176 28 0.32 192 N/A
a. 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. Volume provided in chambers only (no aggregate storage). This number must meet or exceed the required FAA storage volume.
g. System volume includes total number of chambers, plus surrounding aggregate. This number must meet or exceed the required WQCV.
Vault Configuration Summary
Note: "Chamber Volume" refers to the open volume within the vaults. "Installed Chamber Volume" refers to the total volume provided, including the surrounding aggregates.
D:\Projects\1252-005\Drainage\LID\1252-005_Vault Summary.xlsx
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 11, Sep 23, 2016
Soil map units are labeled (as space allows) for map scales
1:50,000 or larger.
Date(s) aerial images were photographed: Mar 20, 2015—Oct
15, 2016
The orthophoto or other base map on which the soil lines were
compiled and digitized probably differs from the background
imagery displayed on these maps. As a result, some minor
shifting of map unit boundaries may be evident.
Custom Soil Resource Report
10
Q C f C i A
Tt
(min)
2-yr
Tc
(min)
10-yr
Tc
(min)
100-yr
Tc
(min)
1 1 No 0.25 0.25 0.31 22 2.00% 5.9 5.9 5.5 207 0.50% 1.41 2.4 0 0.00% N/A N/A 8 8 8
2 2 No 0.25 0.25 0.31 35 2.00% 7.5 7.5 6.9 160 0.50% 1.41 1.9 0 0.00% N/A N/A 9 9 9
3 3 No 0.90 0.90 1.00 55 0.50% 3.5 3.5 1.7 50 0.50% 1.41 0.6 0 0.00% N/A N/A 5 5 5
4 4 No 0.25 0.25 0.31 43 1.30% 9.6 9.6 8.8 215 0.50% 1.41 2.5 0 0.00% N/A N/A 12 12 11
OS1 OS1 No 0.90 0.90 1.00 95 1.20% 3.4 3.4 1.7 460 0.40% 1.26 6.1 0 0.00% N/A N/A 9 9 8
OS2 OS2 No 0.90 0.90 1.00 40 2.00% 1.9 1.9 0.9 435 0.50% 1.41 5.1 0 0.00% N/A N/A 7 7 6
Historic Site
(Pervious
Area)
Historic Site
(Pervious
Area) No 0.25 0.25 0.31 89 0.80% 16.2 16.2 15.0 0 0.00% N/A N/A 0 0.00% N/A N/A 16 16 15
Historic Site
(Impervious
Area)
Historic Site
(Impervious
Area) No 0.25 0.25 0.31 65 1.10% 12.4 12.4 11.5 167 0.60% 1.55 1.8 0 0.00% N/A N/A 14 14 13
TIME OF CONCENTRATION COMPUTATIONS
Gutter Flow Swale Flow
Design
Point
Basin
Overland Flow
ATC
November 27, 2017
Time of Concentration
(Equation RO-4)
3
1
1 . 87 1 . 1 *
S
C Cf L
Ti
(Impervious Area) 61958 1.42 0.65 0.29 0.48 0.00 0.00 0.95 0.95 1.00 94.4%
COMPOSITE % IMPERVIOUSNESS AND RUNOFF COEFFICIENT CALCULATIONS
Runoff Coefficients 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 27, 2017