HomeMy WebLinkAboutSPRADLEY BARR REDEVELOPMENT - PDP - PDP180010 - SUBMITTAL DOCUMENTS - ROUND 1 - DRAINAGE REPORTJuly 25, 2018
PRELIMINARY DRAINAGE AND
EROSION CONTROL REPORT FOR
DRAKE REDEVELOPMENT
Fort Collins, Colorado
Prepared for:
Brinkman Partners
3528 Precision Drive, Suite 100
Fort Collins, CO 80528
Prepared by:
301 N. Howes, Suite 100
Fort Collins, Colorado 80521
Phone: 970.221.4158 Fax: 970.221.4159
www.northernengineering.com
Project Number: 379-072
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.
July 25, 2018
City of Fort Collins
Stormwater Utility
700 Wood Street
Fort Collins, Colorado 80521
RE: Preliminary Drainage and Erosion Control Report for
DRAKE REDEVELOPMENT
Dear Staff:
Northern Engineering is pleased to submit this Preliminary Drainage and Erosion Control Report
for your review. This report accompanies the Project Development Plan submittal for the
proposed Drake Redevelopment 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
Drake Redevelopment
Preliminary 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 ....................................................................................................................... 5
III. DRAINAGE DESIGN CRITERIA ................................................................................... 5
A. Regulations........................................................................................................................................ 5
B. Four Step Process .............................................................................................................................. 5
C. Development Criteria Reference and Constraints ............................................................................ 6
D. Hydrological Criteria ......................................................................................................................... 6
E. Hydraulic Criteria .............................................................................................................................. 6
F. Modifications of Criteria ................................................................................................................... 7
IV. DRAINAGE FACILITY DESIGN .................................................................................... 7
A. General Concept ............................................................................................................................... 7
B. Specific Details .................................................................................................................................. 8
V. CONCLUSIONS ........................................................................................................ 8
A. Compliance with Standards .............................................................................................................. 8
B. Drainage Concept .............................................................................................................................. 8
APPENDICES:
APPENDIX A – Hydrologic Computations
APPENDIX B – LID Information and Computations
APPENDIX C – Erosion Control Report
APPENDIX D – Existing and Proposed Imperviousness
APPENDIX E – USDA Soils Information
LIST OF FIGURES:
Figure 1 – Aerial Photograph ................................................................................................ 2
Figure 2– Proposed Site Plan ................................................................................................ 3
Figure 3 – Existing Floodplains ............................................................................................. 4
MAP POCKET:
Proposed Drainage Exhibit
Drake Redevelopment
Preliminary Drainage Report 1
I. GENERAL LOCATION AND DESCRIPTION
A. Location
1. Vicinity Map
2. The project site is located in the northeast quarter of Section 26, Township 7 North,
Range 69 West of the 6th Principal Meridian, City of Fort Collins, County of Larimer,
State of Colorado.
3. The project site is located just southwest of the intersection of W. Drake Road and
South College Avenue.
4. The project site lies within the Spring Creek Basin. The historic outfall for the site is
the existing South College Avenue storm system. This outfall will be utilized by the
proposed project as the main point of discharge for the developed site. The proposed
site will not be increasing drainage area to the historic South College Avenue outfall
and will reduce overall site imperviousness. An exhibit documenting existing and
proposed imperviousness for the site has been included in the appendix for reference.
Typically, projects are required to detain the difference between the 100-year
developed inflow rate and the historic 2-year release rate. Based on discussions with
City of Fort Collins Stormwater Utility Staff, since the development of the site will
result in a reduction of overall imperviousness detention will not be required.
Drake Redevelopment
Preliminary Drainage Report 2
5. Water quality treatment will be provided in a proposed underground chamber system
and will treat site runoff prior to discharge into the existing South College Avenue
storm system.
6. No offsite flows enter the site as adjacent Rights of Way of Drake Road, Thunderbird
Drive, McClelland Drive, and College Avenue convey offsite flows away from the
project site.
B. Description of Property
1. The development area is roughly 7.08 net acres.
Figure 1 – Aerial Photograph
2. The subject property is currently an existing car dealership. The ground cover
generally consists paved surfaces, rooftops and minimal landscaped area. Existing
ground slopes are mild to moderate (i.e., 1 - 3±%) through the interior of the
property. General topography slopes from west to east.
Drake Redevelopment
Preliminary Drainage Report 3
3. According to the United States Department of Agriculture (USDA) Natural Resources
Conservation Service (NRCS) Soil Survey website:
http://websoilsurvey.nrcs.usda.gov/app/WebSoilSurvey.aspx, the site primarily consists
of Nunn Clay loam, which falls into Hydrologic Soil Group C.
4. The proposed project is a redevelopment of the existing car dealership, and will
consist of a hotel, commercial buildings and multifamily residential buildings.
Associated drives and parking areas, water and sewer lines will be constructed with
the development.
Figure 2– Proposed Site Plan
5. The proposed land use is mixed-use.
Drake Redevelopment
Preliminary Drainage Report 4
C. Floodplain
1. The project site is not encroached by any City designated or FEMA designated 100-
year floodplain.
Figure 3 –Area Floodplain Mapping
II. DRAINAGE BASINS AND SUB-BASINS
A. Major Basin Description
1. The historic outfall for the site is the existing South College Avenue storm system.
This outfall will be utilized by the proposed project as the main point of discharge for
the developed site. The proposed site will not be increasing drainage area to the
historic South College Avenue outfall and will reduce overall site imperviousness. An
exhibit documenting existing and proposed imperviousness for the site has been
included in the appendix for reference. Typically, projects are required to detain the
difference between the 100-year developed inflow rate and the historic 2-year release
rate. Based on discussions with City of Fort Collins Stormwater Utility Staff, since the
development of the site will result in a reduction of overall imperviousness detention
will not be required.
Drake Redevelopment
Preliminary Drainage Report 5
B. Sub-Basin Description
1. The subject property historically drains overland from west to east. Historically, the
development site sheet flows into the adjacent Drake Road, Thunderbird Drive,
McClelland Drive, and College Avenue rights-of-way. Ultimately, all runoff from the
historic site is directed into the existing College Avenue storm line system. The
existing site provides no detention or water quality treatment of existing storm runoff
prior to entering the College Avenue storm line system.
2. The proposed site will generally maintain historic drainage patterns, with all
developed runoff being directed into the existing College Avenue storm line system.
However, the proposed site will reduce overall site imperviousness, and will provide
water quality treatment in an onsite underground chamber system. A more detailed
description of the project drainage patterns is provided below.
III. DRAINAGE DESIGN CRITERIA
A. Regulations
There are no optional provisions outside of the FCSCM proposed with the proposed
project.
B. Four Step Process
The overall stormwater management strategy employed with the proposed project utilizes
the “Four Step Process” to minimize adverse impacts of urbanization on receiving waters.
The following is a description of how the proposed development has incorporated each
step.
Step 1 – Employ Runoff Reduction Practices
Several techniques have been utilized with the proposed development to facilitate the
reduction of runoff peaks, volumes, and pollutant loads as the site is developed from the
current use by implementing multiple Low Impact Development (LID) strategies including:
Conserving existing amenities in the site including the existing vegetated areas.
Providing vegetated open areas throughout the site to reduce the overall impervious
area and to minimize directly connected impervious areas (MDCIA).
Routing flows, to the extent feasible, through vegetated swales to increase time of
concentration, promote infiltration and provide initial water quality.
Step 2 – Implement BMPs That Provide a Water Quality Capture Volume (WQCV) with
Slow Release
The efforts taken in Step 1 will facilitate the reduction of runoff; however, urban
development of this intensity will still generate stormwater runoff that will require
additional BMPs and water quality. The majority of stormwater runoff from the site will
ultimately be intercepted and treated using detention and LID treatment methods prior to
exiting the site.
Step 3 – Stabilize Drainageways
There are no major drainageways within the subject property. While this step may not
seem applicable to proposed development, the project indirectly helps achieve stabilized
drainageways nonetheless. By providing water quality treatment, where none previously
existed, sediment with erosion potential is removed from downstream drainageway
systems. Furthermore, this project will pay one-time stormwater development fees, as
Drake Redevelopment
Preliminary Drainage Report 6
well as ongoing monthly stormwater utility fees, both of which help achieve City-wide
drainageway stability.
Step 4 – Implement Site Specific and Other Source Control BMPs.
The proposed project will improve upon site specific source controls compared to historic
conditions:
The proposed development will provide LID and water quality treatment; thus,
eliminating sources of potential pollution previously left exposed to weathering and
runoff processes.
C. Development Criteria Reference and Constraints
The subject property is surrounded by currently developed properties. Thus, several
constraints have been identified during the course of this analysis that will impact the
proposed drainage system including:
Existing elevations along the property lines will generally be maintained.
As previously mentioned, overall drainage patterns of the existing site will be
maintained.
Elevations of existing downstream facilities that the subject property will release to
will be maintained.
D. Hydrological Criteria
1. The City of Fort Collins Rainfall Intensity-Duration-Frequency Curves, as depicted in
Figure 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.
Drake Redevelopment
Preliminary Drainage Report 7
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. A list of tables and figures used within this report can be found in the Table of
Contents at the front of the document. The tables and figures are located within the
sections to which the content best applies.
3. The drainage patterns anticipated for proposed drainage basins are described below.
Basin 1
Basin 1 consists of the northern and eastern portions of the project site that drain
directly into the adjacent Drake Road and College Avenue rights-of-way. Basin 1 is
composed of landscaped areas that cannot be graded to drain inward towards the
project site. This basin also includes a portion of the access drive into the site from
Drake Road, which for grading purposes was necessary to drain to Drake Road.
Basin 2
Basin 2 consists of the western portion of the project site that drains directly into the
adjacent McClelland Drive Right of Way. Basin 2 is composed of landscaped areas
that cannot be graded to drain inward towards the project site. This basin also
includes a portion of the access drive into the site from McClelland Drive, which for
grading purposes was necessary to drain to McClelland Drive.
Basin 3
Basin 3 consists of the southern portion of the project site that drains directly into the
adjacent Thunderbird Drive Right of Way. Basin 3 is composed of landscaped areas
that cannot be graded to drain inward towards the project site. This basin also
includes a portion of the access drive into the site from Thunderbird Drive, which for
grading purposes was necessary to drain to Thunderbird Drive.
Basin 4 - 10
Basin 4 through 10 consist of landscaped areas, rooftop areas, drives and parking
areas. In general, runoff from these basins will be directed via sheet flow, pans, and
curb and gutter into onsite storm inlets and storm lines. The onsite storm line system
will direct all developed runoff into a series of underground chambers, which will
provide all required water quality treatment for the site as described below. The
underground chamber system will outfall to the existing College Avenue storm system,
also described further below.
A full-size copy of the Drainage Exhibit can be found in the Map Pocket at the end of
this report.
Drake Redevelopment
Preliminary Drainage Report 8
B. Specific Details
1. LID treatment of the majority of developed onsite runoff involving an
underground chamber system will be provided. An interior storm line system
has been designed to capture developed onsite storm runoff and convey runoff
into the chamber system. In storm events which exceed the water quality
design event, excess runoff will bypass the chamber system and be conveyed
into the existing College Avenue storm system. As noted above, a portion of
the site could not be graded to drain into the proposed chamber system.
2. It is noted that the existing College Avenue storm system is currently
undersized for the full 100-year storm event. The design of proposed onsite
storm pipes has been done anticipating future improvements to the College
Avenue storm system and assume that the full 100-year storm will be
adequately conveyed within this system. As such, all onsite storm lines are
designed to convey the full 100-year storm event to the existing College
Avenue storm system.
3. Please see preliminary LID information and Water Quality Capture Volume
(Extended Detention) computations provided in the Appendix.
4. Final design details, and construction documentation shall be provided to the
City of Fort Collins for review prior to Final Development Plan approval.
5. 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 Spring
Creek 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 water quality mitigation
features.
2. The drainage concept for the proposed development is consistent with requirements
for the Spring Creek Basin.
Drake Redevelopment
Preliminary 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. Urban Storm Drainage Criteria Manual, Volumes 1-3, Urban Drainage and Flood Control
District, Wright-McLaughlin Engineers, Denver, Colorado, Revised April 2008.
APPENDIX A
HYDROLOGIC COMPUTATIONS
CHARACTER OF SURFACE:
Runoff
Coefficient
Percentage
Impervious Project: Drake Redevelopment
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 1.01 0.09 0.38 0.00 0.00 0.00 0.55 0.57 0.57 0.71 42%
2 0.56 0.02 0.24 0.00 0.00 0.00 0.31 0.57 0.57 0.71 42%
3 0.23 0.01 0.07 0.00 0.00 0.00 0.14 0.52 0.52 0.65 36%
4 0.29 0.07 0.04 0.00 0.00 0.02 0.16 0.52 0.52 0.66 38%
5 1.88 0.81 0.03 0.94 0.00 0.00 0.10 0.91 0.91 1.00 89%
6 0.81 0.22 0.26 0.22 0.00 0.00 0.10 0.86 0.86 1.00 82%
7 0.77 0.22 0.23 0.20 0.00 0.02 0.09 0.85 0.85 1.00 80%
8 0.63 0.07 0.20 0.32 0.00 0.01 0.03 0.91 0.91 1.00 86%
9 0.46 0.14 0.04 0.00 0.00 0.00 0.28 0.52 0.52 0.65 38%
10 0.45 0.23 0.10 0.05 0.00 0.00 0.07 0.84 0.84 1.00 81%
Overland Flow, Time of Concentration:
Project: Drake Redevelopment
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: Drake Redevelopment
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 1.01 8 8 8 0.57 0.57 0.71 2.40 4.10 8.59 1.4 2.4 6.2 0.70
2 2 0.56 10 10 9 0.57 0.57 0.71 2.26 3.86 8.03 0.7 1.2 3.2 0.36
3 3 0.23 5 5 5 0.52 0.52 0.65 2.85 4.87 9.95 0.3 0.6 1.5 0.17
4 4 0.29 5 5 5 0.52 0.52 0.66 2.85 4.87 9.95 0.4 0.7 1.9 0.22
5 5 1.88 5 5 5 0.91 0.91 1.00 2.85 4.87 9.95 4.9 8.4 18.7 2.44
6 6 0.81 5 5 5 0.86 0.86 1.00 2.85 4.87 9.95 2.0 3.4 8.0 0.99
7 7 0.77 5 5 5 0.85 0.85 1.00 2.85 4.87 9.95 1.9 3.2 7.6 0.93
8 8 0.63 5 5 5 0.91 0.91 1.00 2.85 4.87 9.95 1.6 2.8 6.2 0.81
9 9 0.46 5 5 5 0.52 0.52 0.65 2.85 4.87 9.95 0.7 1.2 3.0 0.34
10 10 0.45 5 5 5 0.84 0.84 1.00 2.85 4.87 9.95 1.1 1.8 4.4 0.53
DEVELOPED RUNOFF COMPUTATIONS
A. Reese
July 25, 2018
Rainfall Intensity taken from the City of Fort Collins Storm Drainage Design Criteria (CFCSDDC), Figure 3.1
Q C f C i A
APPENDIX B
WATER LID INFORMATION AND COMPUTATIONS
T
X
C
D
D
D
D
D
ST
D
TF
TF
TF
TF
TF
DRAKE REDEVELOPMENT
SHEET NO:
D:\PROJECTS\379-072\DWG\DRNG\379-072_LID.DWG
301 N. Howes Street, Suite 100
Fort Collins, Colorado 80521
ENGINEER ING
N O R T H E RN
PHONE: 970.221.4158
www.northernengineering.com
DRAWING REFERENCE:
LID TREATMENT EXHIBIT A. Reese
1 in = 60 ft
July 25, 2018 LID-1
DRAWN BY:
SCALE:
ISSUED:
( IN FEET )
0
1 INCH = 60 FEET
60 60
LEGEND
UNTREATED AREA
STORMTECH CHAMBER AREA
STORMTECH ISOLATOR ROW
TREATMENT AREA
DRAKE REDEVELOPMENT ON-SITE LID TREATMENT
Project Summary
Total Impervious Area 230,699 sf
Target Treatment Percentage 75%
Minimum Area to be Treated by LID measures 173,024.27 sf
Chamber Isolator Rows
Total Chaamber Treatment Area 210,907 sf
Total Treatment Area 210,907 sf
Percent Total Project Area Treated 91.4%
Vault ID
Total
Required
WQ Volume
(cf)
InFlow,
WQ
(cfs)
Chamber
Type
Individual
Chamber
Release
Rate
a
(cfs)
Individual
Chamber
Volume
b
(cfs)
Individual
Installed
Chamber
Volume
c
(cfs)
Mimimum
No. of
Chambers
d
Minimum
Release
Rate
(cfs)
e
Required
Chamber
Volume by
FAA Method
(cf)
Provided
Number of
Chambers
Provided
Release
Rate
e
(cfs)
Provided
Chamber
Volume
f
(cf)
Total
Installed
Chamber
Volume
g
(cf)
Drake Station
Fort Collins, Colorado
A. Reese Date: July 25, 2018
Pond No.: Overall
1
WQ
1.00
Area (A)= 5.28 acres Quantity Detention 2299 ft3
Max Release Rate = 2.38 cfs
Time Time
Ft.Collins
WQ
Intensity
Q100
Inflow
(Runoff)
Volume
Outflow
(Release) Volume
Storage
Detention
Volume
(mins) (secs) (in/hr) (cfs) (ft3) (ft3) (ft3)
5 300 1.43 7.5 2257 715 1543
10 600 1.11 5.8 3501 1429 2071
15 900 0.94 4.9 4443 2144 2299
20 1200 0.81 4.3 5100 2859 2242
25 1500 0.72 3.8 5663 3573 2090
30 1800 0.65 3.4 6178 4288 1890
35 2100 0.59 3.1 6486 5003 1484
40 2400 0.54 2.8 6780 5717 1062
45 2700 0.50 2.6 7057 6432 625
50 3000 0.46 2.4 7286 7146 140
55 3300 0.44 2.3 7579 7861 -282
60 3600 0.41 2.2 7793 8576 -783
65 3900 0.39 2.0 7928 9290 -1363
70 4200 0.37 1.9 8094 10005 -1911
75 4500 0.35 1.8 8197 10720 -2523
80 4800 0.33 1.7 8364 11434 -3071
85 5100 0.32 1.7 8482 12149 -3667
90 5400 0.31 1.6 8696 12864 -4168
95 5700 0.29 1.5 8728 13578 -4851
100 6000 0.28 1.5 8870 14293 -5423
105 6300 0.27 1.4 8981 15008 -6026
110 6600 0.26 1.4 9060 15722 -6662
115 6900 0.3 1.3 9290 16437 -7147
120 7200 0.25 1.3 9314 17152 -7838
Input Variables Results
Design Point
Design Storm Required Detention Volume
Developed "C" =
Chamber Volume Calculation | FAA Method
Project:
Project Location:
Calculations By:
D:\Projects\379-072\Drainage\LID\379-072_LID_Chambers.xlsm\
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\379-072\Drainage\LID\379-072_LID_Chambers.xlsm
WATER QUALITY DESIGN CALCULATIONS
STORMTECH CHAMBER SYSTEM
Project: Drake Redevelopment
By: A. Reese
Date: July 25, 2018
REQUIRED STORAGE & OUTLET WORKS:
BASIN AREA = 5.28 <-- INPUT from impervious calcs
BASIN IMPERVIOUSNESS PERCENT = 78.5 <-- INPUT from impervious calcs
BASIN IMPERVIOUSNESS RATIO = 0.78 <-- CALCULATED
WQCV (watershed inches) = 0.319 <-- CALCULATED from Figure EDB-2
WQCV (ac-ft) = 0.168 <-- CALCULATED from UDFCD DCM V.3 Section 6.5
WQCV (cu-ft) = 7332 <-- CALCULATED from UDFCD DCM V.3 Section 6.5
APPENDIX C
EROSION CONTROL REPORT
Drake Redevelopment
EROSION CONTROL REPORT
A comprehensive Erosion and Sediment Control Plan (along with associated details) will be 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 Plans will contain 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 BMP’S.
APPENDIX D
EXISTING AND PROPOSED IMPERVIOUSNESS
T
T T
AC
T
X
C
DRAKE ROAD
McCLELLAND DRIVE
COLLEGE AVENUE
THUNDERBIRD DRIVE
T
X
C
DRAKE ROAD
McCLELLAND DRIVE
COLLEGE AVENUE
THUNDERBIRD DRIVE
ROOFTOP
ASPHALT
SURFACE
AREA (SF) % IMPERV.
44,282
251,788
2,015
100%
100%
0% 0
TOTALS
EXISTING
44,282
10,524
DRAKE REDEVELOPMENT
FORT COLLINS
COLORADO
301 N. Howes Street, Suite 100
Fort Collins, Colorado 80521
ENGINEER ING
N O R T H E RN
PHONE: 970.221.4158
www.northernengineering.com
DESCRIPTION
EXISTING VS. PROPOSED
IMPERVIOUS AREA
DRAWN BY
B. RUCH
DATE
JULY 25, 2018
PROJECT
374-072 SK-C1
SCALE DRAWING
1"=100'
CONCRETE
LANDSCAPE
IMPERV.
AREA (SF)
10,524
100%
308,609 TOTAL= 306,594
ROOFTOP
CONCRETE
APPENDIX E
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
July 24, 2018
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
73—Nunn clay loam, 0 to 1 percent slopes.................................................13
References............................................................................................................15
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
4488910 4488940 4488970 4489000 4489030 4489060 4489090
4488910 4488940 4488970 4489000 4489030 4489060 4489090
493200 493230 493260 493290 493320 493350 493380 493410 493440 493470 493500
493200 493230 493260 493290 493320 493350 493380 493410 493440 493470 493500
40° 33' 9'' N
105° 4' 49'' W
40° 33' 9'' N
105° 4' 35'' W
40° 33' 2'' N
105° 4' 49'' W
40° 33' 2'' N
105° 4' 35'' W
N
Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 13N WGS84
0 50 100 200 300
Feet
0 20 40 80 120
Meters
Map Scale: 1:1,480 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
Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI
73 Nunn clay loam, 0 to 1 percent
slopes
8.4 100.0%
Totals for Area of Interest 8.4 100.0%
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
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.
Custom Soil Resource Report
11
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
73—Nunn clay loam, 0 to 1 percent slopes
Map Unit Setting
National map unit symbol: 2tlng
Elevation: 4,100 to 5,700 feet
Mean annual precipitation: 14 to 15 inches
Mean annual air temperature: 48 to 52 degrees F
Frost-free period: 135 to 152 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 6 inches: clay loam
Bt1 - 6 to 10 inches: clay loam
Bt2 - 10 to 26 inches: clay loam
Btk - 26 to 31 inches: clay loam
Bk1 - 31 to 47 inches: loam
Bk2 - 47 to 80 inches: loam
Properties and qualities
Slope: 0 to 1 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 (0.1 to 1.0 mmhos/cm)
Sodium adsorption ratio, maximum in profile: 0.5
Available water storage in profile: High (about 9.1 inches)
Interpretive groups
Land capability classification (irrigated): 3e
Land capability classification (nonirrigated): 4e
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
Wages
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
Custom Soil Resource Report
14
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
15
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
16
MAP POCKET
DRAINAGE EXHIBITS
LID
T
X
C
D
D
D
D
D
ST ST
D
TF
TF
TF
TF
TF
CHAMBER WQ AREA
REQUIRED VOLUME: 7,332 CF
PROVIDED VOLUME: 7,565 CF
3
0.23 ac
2
0.56 ac
1
1.01 ac
7
0.77 ac
6
0.81 ac
5
1.88 ac
9
0.46 ac
2 1
3
8
10
6
5
4
10
0.45 ac
4
0.29 ac
8
0.63 ac
7
9
PROPOSED
STORM DRAIN
PROPOSED
INLET
CONNECT TO
EXISTING
STORM DRAIN
CONNECT TO
EXISTING
STORM DRAIN
PROPOSED
INLET
PROPOSED
INLET
PROPOSED
INLET
PROPOSED
INLET
PROPOSED
INLET
PROPOSED
INLET
PROPOSED
STORM DRAIN
ENCHANTE ENTERPRISES LLC
2631 S COLLEGE AVE
PLUTUS HOLDINGS LLC
2633 S COLLEGE AV.
DRAKE ROAD
(ROW VARIES)
McCLELLAND DRIVE
(37' ROW)
COLLEGE AVENUE
(ROW VARIES)
THUNDERBIRD DRIVE
(60' ROW)
PROPOSED
INLET
No. Revisions:
By: Date:
REVIEWED BY:
N. Haws
DESIGNED BY:
DRAWN BY:
SCALE:
DATE:
07/25/18
PROJECT:
379-072
Sheet
DRAKE REDEVELOPMENT
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
07/25/18
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
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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
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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"=30'
21
NORTH
( IN FEET )
1 inch = ft.
30 0 30 Feet
30
60 90
FOR DRAINAGE REVIEW ONLY
NOT FOR CONSTRUCTION
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 PRELIMINARY DRAINAGE REPORT FOR DRAKE REDEVELOPMENT,
DATED JULY 25, 2018 FOR ADDITIONAL INFORMATION.
BASIN
DESIGNATION
AREA BASIN (AC)
BENCHMARK
FOR DRAINAGE REVIEW ONLY
NOT FOR CONSTRUCTION
C
0.60 ac
LID SUMMARY:
RUNOFF TABLE:
PROJECT DATUM: NAVD88
CITY OF FORT COLLINS BENCHMARK 21-92
NORTHWEST CORNER OF WEST DRAKE RD. AND RESEARCH BLVD., ON A POWER TOWER
BASE.
ELEV.= 5042.84
CITY OF FORT COLLINS BENCHMARK 14-97
APPROXIMATELY 100 FEET WEST OF THE INTERSECTION OF CENTRE AVE. AND RESEARCH
BLVD.,ON THE WEST END OF THE SOUTH HEADWALL ON CENTRE AVE.
ELEV.= 5051.76
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 - 3.17'
BASIS OF BEARINGS
THE BASIS OF BEARINGS IS THE NORTH LINE OF THE NORTHEAST QUARTER, SECTION
26-7-69, AS BEARING N 89°30' W.
DRAKE REDEVELOPMENT ON-SITE LID TREATMENT
Project Summary
Total Impervious Area 230,699 sf
Target Treatment Percentage 75%
Minimum Area to be Treated by LID measures 173,024.27 sf
Chamber Isolator Rows
Total Chaamber Treatment Area 210,907 sf
Total Treatment Area 210,907 sf
Percent Total Project Area Treated 91.4%
Basin ID
Basin Area
(s.f.)
Basin Area
(ac)
Composite
% Imperv.
Flow,
WQ
(cfs)
Flow,
Q2
(cfs)
Flow,
Q100
(cfs)
Treatment
Area
(sf)
1 1.01 5.28 0.42 0.70 1.39 6.23 20313.00
2 0.56 0.00 0.42 0.36 0.73 3.23 11256.00
3 0.23 0.00 0.36 0.17 0.34 1.49 3870.00
4 0.29 0.00 0.38 0.22 0.43 1.90 5565.41
5 1.88 0.00 0.89 2.44 4.89 18.71 77504.47
6 0.81 0.00 0.82 0.99 1.98 8.03 30754.42
7 0.77 0.00 0.80 0.93 1.86 7.63 29367.31
8 0.63 0.00 0.86 0.81 1.62 6.23 25969.36
9 0.46 0.00 0.38 0.34 0.69 3.00 7836.15
10 0.45 0.00 0.81 0.53 1.07 4.43 16430.24
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 12, Oct 10, 2017
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
ASPHALT
PAVERS
SURFACE
AREA (SF) % IMPERV.
IMPERV.
AREA (SF)
76,872
83,346
88,824
1,713
100%
100%
100%
40%
TOTALS 308,609 TOTAL= 249,728
76,872
686
251,788
83,346
88,824
LANDSCAPE 57,854 0% 0
PROPOSED
1 7332 6.3 SC-740 0.024 45.90 74.90 98 2.31 2299 101 2.38 4636 7565
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.
Chamber 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.
7/24/2018 D:\Projects\379-072\Drainage\LID\379-072_LID_Chambers.xlsm
(min)
10-yr
Tc
(min)
100-yr
Tc
(min)
1 1 No 0.25 0.25 0.31 36 4.72% 5.7 5.7 5.3 322 0.99% 1.99 2.7 0 n/a N/A N/A 8 8 8
2 2 No 0.25 0.25 0.31 35 3.43% 6.2 6.2 5.8 336 0.60% 1.54 3.6 0 n/a N/A N/A 10 10 9
3 3 No 0.90 0.90 1.00 41 2.68% 1.7 1.7 0.9 159 1.76% 2.65 1.0 0 n/a N/A N/A 5 5 5
4 4 No 0.90 0.90 1.00 61 2.13% 2.3 2.3 1.1 83 0.72% 1.70 0.8 0 n/a N/A N/A 5 5 5
5 5 No 0.90 0.90 1.00 222 2.61% 4.0 4.0 2.0 141 1.35% 2.32 1.0 0 n/a N/A N/A 5 5 5
6 6 No 0.90 0.90 1.00 88 2.05% 2.8 2.8 1.4 122 1.31% 2.29 0.9 0 n/a N/A N/A 5 5 5
7 7 No 0.90 0.90 1.00 76 1.58% 2.8 2.8 1.4 51 1.18% 2.17 0.4 0 n/a N/A N/A 5 5 5
8 8 No 0.90 0.90 1.00 41 2.20% 1.8 1.8 0.9 18 1.67% 2.58 0.1 0 n/a N/A N/A 5 5 5
9 9 No 0.90 0.90 1.00 49 1.02% 2.6 2.6 1.3 63 2.54% 3.19 0.3 0 n/a N/A N/A 5 5 5
10 10 No 0.90 0.90 1.00 77 1.69% 2.8 2.8 1.4 18 2.22% 2.98 0.1 0 n/a N/A N/A 5 5 5
DEVELOPED TIME OF CONCENTRATION COMPUTATIONS
Gutter Flow Swale Flow
Design
Point
Basin
Overland Flow
A. Reese
July 25, 2018
Time of Concentration
(Equation RO-4)
3
1
1 . 87 1 . 1 *
S
C Cf L
Ti
Total Onsite 5.28 1.76 0.90 1.74 0.00 0.05 0.84 0.83 0.83 1.00 78%
DEVELOPED 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
July 25, 2018