HomeMy WebLinkAboutTHE UNION ON ELIZABETH (FORMERLY 1208 W. ELIZABETH STREET) - PDP/FDP - FDP170024 - SUBMITTAL DOCUMENTS - ROUND 1 - DRAINAGE REPORTAugust 16, 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.
August 16, 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 ....................................................................... 4
A. Major Basin Description .................................................................................................................... 4
B. Sub-Basin Description ....................................................................................................................... 4
III. DRAINAGE DESIGN CRITERIA ................................................................................... 5
A. Regulations........................................................................................................................................ 5
B. Four Step Process .............................................................................................................................. 5
C. Development Criteria Reference and Constraints ............................................................................ 5
D. Hydrological Criteria ......................................................................................................................... 6
E. Hydraulic Criteria .............................................................................................................................. 6
F. Modifications of Criteria ................................................................................................................... 6
IV. DRAINAGE FACILITY DESIGN .................................................................................... 6
A. General Concept ............................................................................................................................... 6
B. Specific Details .................................................................................................................................. 7
V. CONCLUSIONS ........................................................................................................ 8
A. Compliance with Standards .............................................................................................................. 8
B. Drainage Concept .............................................................................................................................. 8
APPENDICES:
APPENDIX A – Hydrologic Computations, Historic Drainage Exhibit
APPENDIX B - USDA Soils Information
APPENDIX C – Hydraulic Computations
APPENDIX D – Water Quality Calculations, LID Information Detention Calculations
APPENDIX E – Detention Calculations
APPENDIX F – Erosion Control Report
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. We will be providing water quality treatment for the remainder of the 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 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 City designated or FEMA 100-year
floodplain.
Figure 3 –Area Floodplain Mapping
II. DRAINAGE BASINS AND SUB-BASINS
A. Major Basin Description
1. The 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
Elizabeth Street.
2. A more detailed description of the project drainage patterns is provided below.
PROJECT SITE
Union on Elizabeth
Final Drainage Report 5
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:
Conserving existing amenities in the site.
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:
The proposed development will provide LID 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.
Union on Elizabeth
Final Drainage Report 6
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 sand filter, as discussed further below.
3. Drainage patterns anticipated for drainage basins shown in the Drainage Exhibit are
described below.
Basins 1 and 5
Basin 1 is primarily composed of landscaped areas and will generally drain via swale
flow into a curb chase, which will direct runoff into Elizabeth Street. Basin 5 is also
primarily composed of landscaped areas and will generally drain via sheet into
Elizabeth Street. Runoff from these basins will not be detained; therefore, the overall
site release rate will reduced to compensate for this undetained release.
Union on Elizabeth
Final Drainage Report 7
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 these basins will be detained and receive LID treatment within a proposed
paver system and concrete vault/sand filter, as discussed further below. The proposed
concrete vault in Basin 3 will release into the subdrain system within the proposed
paver system in Basin 2. This subrain system will outfall to the adjacent north curb
and gutter of Elizabeth Street.
Basin 4
Basin 4 is composed of landscaped areas and an access drive. This basin will
generally drain via swale flow into a bioswale and a raingarden and receive LID
treatment, as discussed further below. A portion of the basin will drain via a curb
chase into Elizabeth Street. The remainder of the basin will drain directly into the
north curb and gutter of Elizabeth Street. Runoff from this basin will not be detained;
therefore, the overall site release rate will reduced to compensate for this undetained
release.
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 subgrade
detention system will be provided within the subgrade of the paver system
proposed within Drainage Basin 2, and a concrete vault detention system will
be provided within the building envelope shown within Drainage Basin 3.
2. LID features within the site include a paver system in Basin 2, a sand filter in
Basin 3, and a bioswale and raingarden in Basin 4.
3. Standard water quality treatment (Extended Detention) is required for 50% of
the site. Extended Detention will be provided within the proposed paver
system subgrade and the concrete vault.
4. A total combined release rate has been determined for the proposed detention
facilities has been set at 7.22 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 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 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 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, 4, and 5 (2.95
cfs total) for an allowable release rate of 7.22 cfs.
5. Stormwater facility Standard Operating Procedures (SOP) will be provided by
the City of Fort Collins in the Development Agreement.
Union on Elizabeth
Final Drainage Report 8
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
Poudre River 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 Basin.
Union on Elizabeth
Final Drainage Report 9
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 Scot 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…………………………...………………..…………………………………………….. 0.40 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
(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 13026 0.30 0.00 0.03 0.00 0.01 0.25 0.33 0.33 0.41 9.0%
2 22216 0.51 0.00 0.00 0.30 0.16 0.05 0.71 0.71 0.89 52.9%
3 45387 1.04 0.00 0.00 0.75 0.00 0.29 0.75 0.75 0.94 64.8%
4 15314 0.35 0.13 0.00 0.00 0.00 0.22 0.51 0.51 0.64 37.0%
5 762 0.017 0.00 0.00 0.00 0.00 0.02 0.25 0.25 0.31 0.0%
OS1 135036 3.10 2.28 0.07 0.51 0.16 0.08 0.88 0.88 1.00 90.4%
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) 96704 0.84 0.00 0.00 0.00 0.00 0.84 0.25 0.25 0.31 0.0%
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 0.30 8 8 8 0.33 0.33 0.41 2.40 4.10 8.59 0.24 0.40 1.05
2 2 0.51 9 9 9 0.71 0.71 0.89 2.30 3.93 8.21 0.83 1.42 3.71
3 3 1.04 5 5 5 0.75 0.75 0.94 2.85 4.87 9.95 2.24 3.83 9.77
4 4 0.35 9 9 9 0.51 0.51 0.64 2.30 3.93 8.21 0.41 0.70 1.83
5 5 0.02 5 5 5 0.25 0.25 0.31 2.85 4.87 9.95 0.01 0.02 0.05
OS1 OS1 3.10 9 9 8 0.88 0.88 1.00 2.30 3.93 8.59 6.30 10.76 26.63
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) 0.84 20 20 18 0.25 0.25 0.31 1.63 2.78 5.92 0.34 0.58 1.55
Historic Site
(Impervious
Area)
Historic Site
(Impervious Area) 1.44 21 21 19 0.95 0.95 1.19 1.59 2.71 5.75 2.17 3.70 9.83
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)
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
Runoff Chapter 6
6-8 Urban Drainage and Flood Control District January 2016
Urban Storm Drainage Criteria Manual Volume 1
Table 6-3. Recommended percentage imperviousness values
Land Use or Percentage Imperviousness
Surface Characteristics (%)
Business:
Downtown Areas 95
Suburban Areas 75
Residential:
Single-family
2.5 acres or larger 12
0.75 – 2.5 acres 20
0.25 – 0.75 acres 30
0.25 acres or less 45
Apartments 75
Industrial:
Light areas 80
Heavy areas 90
Parks, cemeteries 10
Playgrounds 25
Schools 55
Railroad yard areas 50
Undeveloped Areas:
Historic flow analysis 2
Greenbelts, agricultural 2
Off-site flow analysis (when land use not
defined) 45
Streets:
Paved 100
Gravel (packed) 40
Drive and walks 90
Roofs 90
Lawns, sandy soil 2
Lawns, clayey soil 2
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
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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
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References
American Association of State Highway and Transportation Officials (AASHTO).
2004. Standard specifications for transportation materials and methods of sampling
and testing. 24th edition.
American Society for Testing and Materials (ASTM). 2005. Standard classification of
soils for engineering purposes. ASTM Standard D2487-00.
Cowardin, L.M., V. Carter, F.C. Golet, and E.T. LaRoe. 1979. Classification of
wetlands and deep-water habitats of the United States. U.S. Fish and Wildlife
Service FWS/OBS-79/31.
Federal Register. July 13, 1994. Changes in hydric soils of the United States.
Federal Register. September 18, 2002. Hydric soils of the United States.
Hurt, G.W., and L.M. Vasilas, editors. Version 6.0, 2006. Field indicators of hydric
soils in the United States.
National Research Council. 1995. Wetlands: Characteristics and boundaries.
Soil Survey Division Staff. 1993. Soil survey manual. Soil Conservation Service.
U.S. Department of Agriculture Handbook 18. http://www.nrcs.usda.gov/wps/portal/
nrcs/detail/national/soils/?cid=nrcs142p2_054262
Soil Survey Staff. 1999. Soil taxonomy: A basic system of soil classification for
making and interpreting soil surveys. 2nd edition. Natural Resources Conservation
Service, U.S. Department of Agriculture Handbook 436. http://
www.nrcs.usda.gov/wps/portal/nrcs/detail/national/soils/?cid=nrcs142p2_053577
Soil Survey Staff. 2010. Keys to soil taxonomy. 11th edition. U.S. Department of
Agriculture, Natural Resources Conservation Service. http://
www.nrcs.usda.gov/wps/portal/nrcs/detail/national/soils/?cid=nrcs142p2_053580
Tiner, R.W., Jr. 1985. Wetlands of Delaware. U.S. Fish and Wildlife Service and
Delaware Department of Natural Resources and Environmental Control, Wetlands
Section.
United States Army Corps of Engineers, Environmental Laboratory. 1987. Corps of
Engineers wetlands delineation manual. Waterways Experiment Station Technical
Report Y-87-1.
United States Department of Agriculture, Natural Resources Conservation Service.
National forestry manual. http://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/
home/?cid=nrcs142p2_053374
United States Department of Agriculture, Natural Resources Conservation Service.
National range and pasture handbook. http://www.nrcs.usda.gov/wps/portal/nrcs/
detail/national/landuse/rangepasture/?cid=stelprdb1043084
16
United States Department of Agriculture, Natural Resources Conservation Service.
National soil survey handbook, title 430-VI. http://www.nrcs.usda.gov/wps/portal/
nrcs/detail/soils/scientists/?cid=nrcs142p2_054242
United States Department of Agriculture, Natural Resources Conservation Service.
2006. Land resource regions and major land resource areas of the United States,
the Caribbean, and the Pacific Basin. U.S. Department of Agriculture Handbook
296. http://www.nrcs.usda.gov/wps/portal/nrcs/detail/national/soils/?
cid=nrcs142p2_053624
United States Department of Agriculture, Soil Conservation Service. 1961. Land
capability classification. U.S. Department of Agriculture Handbook 210. http://
www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/nrcs142p2_052290.pdf
Custom Soil Resource Report
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APPENDIX C
Water Quality Computations, LID Information
WATER QUALITY CAPTURE VOLUME DESIGN CALCULATIONS
40-Hour Extended Detention (Paver Subgrade)
Project: 1252-005
By: ATC
Date: 8/1/17
REQUIRED STORAGE & OUTLET WORKS:
BASIN AREA = 0.510 <-- INPUT from impervious calcs
BASIN IMPERVIOUSNESS PERCENT = 52.90 <-- INPUT from impervious calcs
BASIN IMPERVIOUSNESS RATIO = 0.5290 <-- CALCULATED
WQCV (watershed inches) = 0.214 <-- CALCULATED from USDCM Vol.3, Figure 3-2
WQCV (ac-ft) = 0.011 <-- CALCULATED from USDCM Vol.3, EQ 3-3
WQ Depth (ft) = 3.000 <-- INPUT from stage-storage table
AREA REQUIRED PER ROW, a (in2) = 0.040 <-- CALCULATED from Figure EDB-3
CIRCULAR PERFORATION SIZING:
dia (in) = 1/4 <-- INPUT from Figure 5
n = 3 <-- INPUT from Figure 5
t (in) = 1/4 <-- INPUT from Figure 5
number of rows = 1 <-- CALCULATED from WQ Depth and row spacing
WATER QUALITY CAPTURE VOLUME DESIGN CALCULATIONS
40-Hour Extended Detention (Concrete Vault)
Project: 1252-005
By: ATC
Date: 8/1/17
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 = 3 <-- INPUT from Figure 5
t (in) = 1/4 <-- INPUT from Figure 5
number of rows = 1 <-- CALCULATED from WQ Depth and row spacing
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.
RG1 0.20 0.08 0.00 0.00 0.00 0.00 0.12 0.53 0.53 0.66 40%
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
August 16, 2017
Sheet 1 of 2
Designer:
Company:
Date:
Project:
Location:
1. Basin Storage Volume
A) Effective Imperviousness of Tributary Area, Ia Ia = 40.0 %
(100% if all paved and roofed areas upstream of rain garden)
B) Tributary Area's Imperviousness Ratio (i = Ia/100) i = 0.400
C) Water Quality Capture Volume (WQCV) for a 12-hour Drain Time WQCV = 0.14 watershed inches
(WQCV= 0.8 * (0.91* i3 - 1.19 * i2 + 0.78 * i)
D) Contributing Watershed Area (including rain garden area) Area = 8,609 sq ft
E) Water Quality Capture Volume (WQCV) Design Volume VWQCV = 103 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 = cu ft
(Only if a different WQCV Design Volume is desired)
2. Basin Geometry
A) WQCV Depth (12-inch maximum) DWQCV = 4 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 = 69 sq ft
D) Actual Flat Surface Area AActual = 346 sq ft
E) Area at Design Depth (Top Surface Area) ATop = 346 sq ft
F) Rain Garden Total Volume VT= 115 cu ft
(VT= ((ATop + AActual) / 2) * Depth)
3. Growing Media
4. Underdrain System
A) Are underdrains provided?
B) Underdrain system orifice diameter for 12 hour drain time
i) Distance From Lowest Elevation of the Storage y = N/A ft
Volume to the Center of the Orifice
ii) Volume to Drain in 12 Hours Vol12 = N/A cu ft
iii) Orifice Diameter, 3/8" Minimum DO = N/A in
Design Procedure Form: Rain Garden (RG)
A. Reese
Northern Engineering
August 16, 2017
Union on Elizabeth
Rain Garden 1 (Landscape island on east side of project)
Choose One
Choose One
18" Rain Garden Growing Media
Other (Explain):
YES
NO
RG01_UD-BMP_v3.03.xlsm, RG 8/15/2017, 2:24 PM
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
NO SPRINKLER HEADS ON FLAT SURFACE
A) Will the rain garden be irrigated?
Notes:
Design Procedure Form: Rain Garden (RG)
A. Reese
Northern Engineering
August 16, 2017
Union on Elizabeth
Rain Garden 1 (Landscape island on east side of project)
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
RG01_UD-BMP_v3.03.xlsm, RG 8/15/2017, 2:24 PM
APPENDIX D
Hydraulic Calculations
Channel Report
Hydraflow Express Extension for Autodesk® AutoCAD® Civil 3D® by Autodesk, Inc. Tuesday, Aug 15 2017
West Side Conveyance
User-defined
Invert Elev (ft) = 29.08
Slope (%) = 0.50
N-Value = 0.015
Calculations
Compute by: Known Depth
Known Depth (ft) = 0.95
(Sta, El, n)-(Sta, El, n)...
( 0.00, 31.00)-(5.00, 29.92, 0.012)-(25.00, 29.82, 0.012)-(29.00, 29.08, 0.020)-(31.00, 29.08, 0.020)-(36.50, 31.00, 0.020)
Highlighted
Depth (ft) = 0.95
Q (cfs) = 27.92
Area (sqft) = 8.74
Velocity (ft/s) = 3.19
Wetted Perim (ft) = 29.47
Crit Depth, Yc (ft) = 0.96
Top Width (ft) = 29.23
EGL (ft) = 1.11
-5 0 5 10 15 20 25 30 35 40 45
Elev (ft) Depth (ft)
Section
28.50 -0.58
29.00 -0.08
29.50 0.42
30.00 0.92
30.50 1.42
31.00 1.92
31.50 2.42
32.00 2.92
Sta (ft)
Hydraflow Plan View
Project File: Storm_Outfall.stm No. Lines: 3 08-15-2017
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 8 1.60 5028.15 5028.74 0.59 0.33 4.89 0.37 5029.11 1.569 8.0 5028.15 5028.92 0.67 0.35 4.58 0.33 5029.25 1.755 1.662 0.133 0.78 0.25
2 8 1.60 5028.15 5029.17 0.67 0.35 4.58 0.33 5029.50 1.756 37.9 5028.15 5029.84 0.67 0.35 4.58 0.33 5030.17 1.755 1.756 0.665 0.78 0.25
3 8 1.60 5028.15 5030.09 0.67 0.35 4.58 0.33 5030.42 1.756 12.0 5028.15 5030.31 0.67 0.35 4.58 0.33 5030.63 1.755 1.756 0.211 1.00 0.33
Project File: Storm_Outfall.stm Number of lines: 3 Run Date: 08-15-2017
Hydraflow Storm Sewers 2005
APPENDIX E
Detention Calculations
ATC
Pond No : Concrete Vault
3
100-yr
0.94
Area (A)= 1.04 acres 8631 ft3
Max Release Rate = 0.60 cfs 0.198 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 9.73 2918 180.0 2738.1
10 600 7.720 7.55 4528 360.0 4168.2
15 900 6.520 6.37 5737 540.0 5196.6
20 1200 5.600 5.47 6569 720.0 5849.5
25 1500 4.980 4.87 7303 900.0 6402.7
30 1800 4.520 4.42 7954 1080.0 6873.8
35 2100 4.080 3.99 8376 1260.0 7116.1
40 2400 3.740 3.66 8775 1440.0 7334.9
45 2700 3.460 3.38 9133 1620.0 7512.7
50 3000 3.230 3.16 9473 1800.0 7672.9
55 3300 3.030 2.96 9775 1980.0 7795.0
60 3600 2.860 2.80 10065 2160.0 7905.4
65 3900 2.720 2.66 10370 2340.0 8030.4
70 4200 2.590 2.53 10634 2520.0 8114.3
75 4500 2.480 2.42 10910 2700.0 8210.0
80 4800 2.380 2.33 11168 2880.0 8288.1
85 5100 2.290 2.24 11417 3060.0 8357.4
90 5400 2.210 2.16 11667 3240.0 8426.7
95 5700 2.130 2.08 11869 3420.0 8449.0
100 6000 2.060 2.01 12083 3600.0 8483.1
105 6300 2.000 1.96 12318 3780.0 8537.8
110 6600 1.940 1.90 12517 3960.0 8557.2
115 6900 1.890 1.85 12749 4140.0 8608.9
120 7200 1.840 1.80 12951 4320.0 8631.2
Developed "C" =
1.35
Calculations By:
Input Variables Results
Design Point
Design Storm Required Detention Volume
DETENTION POND CALCULATION; FAA METHOD
Project Number : 1252-005
Date : 8-1-17
Project Location : Fort Collins
OUTLET RATING CURVE
Concrete Vault Detention Orifice
Project: 1252-005
Date: 8/1/2017
By: ATC
100-YR ORIFICE RATING
Orifice Dia (in) 3.50
Orifice Area (sf) 0.0668
Orifice invert (ft) 0.00
Orifice Coefficient 0.65
Outlet
Orifice Area Stage release
(SF) (FT) (CFS)
0.0668 0.00 0.00
0.0668 0.25 0.17
0.0668 0.50 0.25
0.0668 0.75 0.30
0.0668 1.00 0.35
0.0668 1.25 0.39
0.0668 1.50 0.43
0.0668 1.75 0.46
0.0668 2.00 0.49
0.0668 2.25 0.52
0.0668 2.50 0.55
ATC
Pond No : Paver Subgrade
2
100-yr
0.89
Area (A)= 0.51 acres 1893 ft3
Max Release Rate = 1.00 cfs 0.043 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 4.52 1355 300.0 1054.9
10 600 7.720 3.50 2102 600.0 1502.5
15 900 6.520 2.96 2663 900.0 1763.5
20 1200 5.600 2.54 3050 1200.0 1850.2
25 1500 4.980 2.26 3391 1500.0 1890.6
30 1800 4.520 2.05 3693 1800.0 1892.9
35 2100 4.080 1.85 3889 2100.0 1789.0
40 2400 3.740 1.70 4074 2400.0 1674.2
45 2700 3.460 1.57 4240 2700.0 1540.3
50 3000 3.230 1.47 4398 3000.0 1398.3
55 3300 3.030 1.38 4539 3300.0 1238.5
60 3600 2.860 1.30 4673 3600.0 1073.4
65 3900 2.720 1.23 4815 3900.0 915.0
70 4200 2.590 1.18 4938 4200.0 737.5
75 4500 2.480 1.13 5066 4500.0 565.5
80 4800 2.380 1.08 5185 4800.0 385.4
85 5100 2.290 1.04 5301 5100.0 201.1
90 5400 2.210 1.00 5417 5400.0 16.8
95 5700 2.130 0.97 5511 5700.0 -189.2
100 6000 2.060 0.94 5610 6000.0 -389.8
105 6300 2.000 0.91 5719 6300.0 -580.9
110 6600 1.940 0.88 5812 6600.0 -788.3
115 6900 1.890 0.86 5919 6900.0 -980.7
120 7200 1.840 0.84 6013 7200.0 -1186.7
DETENTION POND CALCULATION; FAA METHOD
Project Number : 1252-005
Date : 8-1-17
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: 8/1/2017
By: ATC
100-YR ORIFICE RATING
Orifice Dia (in) 5.70
Orifice Area (sf) 0.1772
Orifice invert (ft) 0.00
Orifice Coefficient 0.65
Outlet
Orifice Area Stage release
(SF) (FT) (CFS)
0.1772 0.00 0.00
0.1772 0.25 0.46
0.1772 0.50 0.65
0.1772 0.75 0.80
0.1772 1.00 0.92
0.1772 1.25 1.03
0.1772 1.50 1.13
0.1772 1.75 1.22
0.1772 2.00 1.31
0.1772 2.25 1.39
0.1772 2.50 1.46
0.1772 2.75 1.53
0.1772 3.00 1.60
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.
MAP POCKET
Drainage Exhibit
LS 23524
FDC
VAULT
F.O.
FO
T
T
CABLE
X X X
X
X
X X
X X
X
X
X
X X
X X
X
X X
T T
T
T T
T
T
T
T
T
X
TF
X
UD
UD
UD UD UD UD
UD UD UD UD UD
UD
CTV
CTV CTV CTV CTV
CTV CTV
CTV CTV CTV CTV CTV CTV
CTV
CTV CTV CTV CTV
CTV
CTV CTV
CTV
CTV
CTV
CTV
CTV
CTV
CTV CTV CTV
CTV
CTV
CTV
CTV CTV CTV
FO FO FO
FO
FO
FO FO FO
FO FO FO
FO FO
FO FO FO
FO FO
FO
FO
FO
FO
FO
FO
FO
FO
FO FO
FO
FO
FO
FO
FO
FO
FO
FO
UD UD
UD
UD UD
UD
UD
UD UD UD UD
UD UD UD UD UD
UD
CTV
CTV CTV CTV CTV
CTV CTV
CTV CTV CTV CTV CTV CTV
CTV
CTV CTV CTV CTV
CTV
CTV CTV
CTV
CTV
CTV
CTV
CTV
CTV
CTV CTV CTV
CTV
CTV
CTV
CTV CTV CTV
FO FO FO
FO
FO
FO FO FO
FO FO FO
FO FO
FO FO FO
FO FO
FO
FO
FO
FO
FO
FO
FO
FO
FO FO
FO
FO
FO
FO
FO
FO
FO
FO
UD UD
UD
UD UD
1
1 2
3 4
2
3
4
5
5
PROPOSED 2'
SIDEWALK CHASE PROPOSED 2'
SIDEWALK CHASE
EXISTING 2'
SIDEWALK CHASE
PROPOSED 8" HDPE
UNDERDRAIN
PROPOSED INLET PROPOSED
STORM DRAIN
PROPOSED
OUTLET STRUCTURE
VAULT
AREA
PROPOSED 2'
CONCRETE PAN
PROPOSED 2'
CONCRETE PAN
PROPOSED 4'
CONCRETE PAN
PROPOSED 2'
CURB CUT
PROPOSED 4'
CONCRETE PAN
PROPOSED 2'
CURB CUT
APPROXIMATE LOCATION
EXISTING 24" RCP STORM DRAIN
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)
OS1
OS1
OS2
OS2
SEE DRAINAGE REPORT FOR
HISTORIC DRAINAGE EXHIBIT
SHOWING OFFSITE BASIN DELINEATION
SEE DRAINAGE REPORT FOR
HISTORIC DRAINAGE EXHIBIT
SHOWING OFFSITE BASIN DELINEATION
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
C700
DRAINAGE EXHIBIT
NORTH
( IN FEET )
1 inch = ft.
20 0 20 Feet
20
40 60
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
ENGINEER ING
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
16 of 17
LEGEND:
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 AUGUST 16, 2017 FOR
ADDITIONAL INFORMATION.
BENCHMARK
FOR DRAINAGE REVIEW ONLY
NOT FOR CONSTRUCTION
C
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 NORTH LINE OF LOT 4 AS BEARING SOUTH 88°52'58" EAST.
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 0.30 0.33 0.41 8.4 7.9 0.2 1.1
2 2 0.51 0.71 0.89 9.3 8.8 0.8 3.7
3 3 1.04 0.75 0.94 5.0 5.0 2.2 9.8
4 4 0.35 0.51 0.64 9.2 8.7 0.4 1.8
5 5 0.017 0.25 0.31 5.0 5.0 0.012 0.054
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
August 1, 2017
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 28 2.00% 6.7 6.7 6.2 215 0.50% 1.41 2.5 0 0.00% N/A N/A 9 9 9
5 5 No 0.25 0.25 0.31 5 2.00% 2.8 2.8 2.6 0 0.00% N/A N/A 0 0.00% N/A N/A 5 5 5
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 0.31 130 0.80% 19.5 19.5 18.1 0 0.00% N/A N/A 0 0.00% N/A N/A 20 20 18
Historic Site
(Impervious
Area)
Historic Site
(Impervious
Area) No 0.25 0.25 0.31 95 0.60% 18.4 18.4 17.0 209 0.60% 1.55 2.2 0 0.00% N/A N/A 21 21 19
TIME OF CONCENTRATION COMPUTATIONS
Gutter Flow Swale Flow
Design
Point
Basin
Overland Flow
ATC
August 1, 2017
Time of Concentration
(Equation RO-4)
3
1
1 . 87 1 . 1 *
S
C Cf L
Ti
Historic Site
(Impervious Area) 218715 1.44 0.67 0.29 0.48 0.00 0.00 0.95 0.95 1.19 94.7%
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
August 1, 2017