HomeMy WebLinkAboutPRECISION TECHNOLOGY - FDP200029 - - DRAINAGE REPORTFINAL DRAINAGE REPORT
19 OLD TOWN SQUARE #238 | FORT COLLINS, CO 80524 | 970-530-4044 | www.unitedcivil.com
P RECISION T ECHNOLOGY
Harmony Technology Park Fifth Filing Lot 2
Fort Collins, CO
Prepared for:
Precision Technology LLC
224 Canyon Avenue Unit 624
Fort Collins, CO 80521
Date:
December 9 th , 2020
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City of Fort Collins
Stormwater Utility
700 Wood Street
Fort Collins, Colorado 80521
RE: Precision Technology
Final Drainage Report
Fort Collins, Colorado
Project Number: U20015
Dear Staff:
United Civil Design Group, LLC. is pleased to submit this Final Drainage Report for the Precision Technology site in Fort Collins,
Colorado. In general, this report serves to document the stormwater impacts associated with the proposed improvements
related to the existing site.
We understand that review by the City of Fort Collins is to assure general compliance with standardized criteria contained in
the Fort Collins Stormwater Criteria Manual (FCSCM). This report was prepared in compliance with technical criteria set forth
in both the Urban Drainage and Flood Control District (UDFCD) Urban Storm Drainage Criteria Manual and the Fort Collins
Stormwater Criteria Manual.
If you should have any questions or comments as you review this report, please feel free to contact us at your convenience.
Sincerely,
United Civil Design Group, LLC
Nate Stroud, PE, LSIT
Professional Engineer II
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TABLE OF CONTENTS
I. General Location and Description ......................................................................................................................1
A. Location and Project Description ................................................................................................. 1
B. Description of Property ................................................................................................................ 2
C. Floodplains ................................................................................................................................... 2
II. Drainage Basins and Sub-Basins .........................................................................................................................2
A. Major Basin Description ............................................................................................................... 2
B. Sub-Basin Description .................................................................................................................. 3
III. Drainage Design Criteria ....................................................................................................................................3
A. Regulations ................................................................................................................................... 3
B. Directly Connected Impervious Area (DCIA) ................................................................................ 3
C. Hydrological Criteria ..................................................................................................................... 3
D. Hydraulic Criteria.......................................................................................................................... 4
E. Modifications of Criteria .............................................................................................................. 4
IV. Drainage Facility Design .....................................................................................................................................4
A. General Concept ........................................................................................................................... 4
B. Specific Details ............................................................................................................................. 4
V. Erosion Control ...................................................................................................................................................9
VI. Conclusions ........................................................................................................................................................9
A. Compliance with Standards ......................................................................................................... 9
B. Drainage Concept ......................................................................................................................... 9
C. Stormwater Quality .................................................................................................................... 10
VII. References ................................................................................................................................................... 11
APPENDICES
APPENDIX A – Hydrology Calculations
APPENDIX B – Hydraulic Calculations
B.1 – Low Impact Development Calculations
B.2 – Water Quality Calculations
B.3 – Orifice Calculations (Reserved for Final Submittal)
B.4 – Inlet Sizing Calculations (Reserved for Final Submittal)
B.5 – Storm Pipe Calculations (Reserved for Final Submittal)
B.6 – Curb Channel Calculations (Reserved for Final Submittal)
B.7 – Weir Calculation (Reserved for Final Submittal)
APPENDIX C – Referenced Materials
APPENDIX D – Drainage Exhibits
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I.GENERAL LOCATION AND DESCRIPTION
A.LOCATION AND PROJECT DESCRIPTION
The Precision Technology site (referred herein as “the site”) is the development of Lot 2, Harmony Technology Park Fifth
Filing, located in the northwest quarter of Section 4, Township 6 North, Range 68 West of the 6th P.M., City of Fort Collins,
Larimer County, Colorado. The property, consisting of approximately 4.65 acres, is located immediately north of Precision
Drive, approximately 350-feet east of Technology Parkway and currently exists as vacant land in Harmony Technology Park.
The proposed site improvements are limited to the 4.65 acres contained in Lot 2.
The property is bounded by Precision Drive to the south, recently developed commercial businesses to the east and west,
and an existing detention pond and park in the lot to the north. On site detention will not be provided with this site and was
previously included in the Harmony Technology Park Stormwater Plan. A majority of the stormwater on the site currently
drains southeast via sheet flow to existing drainage swales which is then collected by storm sewer infrastructure in Precision
Drive and ultimately conveyed to a regional detention pond (Pond 110) at the intersection of Lady Moon Drive and Rock
Creek Drive. There is also a small portion of the site that drains north via sheet flow to the existing Harmony Commons Pond
which combines ponds 101, 301, and 600 from the previously mentioned master plan. Refer to the appendix for more
information regarding the existing master plan and detention ponds.
The proposed development of the site consists of the construction of a new commercial building with a 106,700-sf footprint.
Associated with the building are proposed drive lanes, parking, utilities, and water quality features. On-site stormwater is
largely designed to discharge to the existing stormwater infrastructure in Precision Drive.
FIGURE 1:SITE VICINITY MAP
In general, this report serves to provide an analysis of the drainage impacts associated with the development of site as it
relates to existing and proposed drainage facilities on-site and to confirm that the development adheres to the requirements
set forth in the master drainage study for the subdivision.
Precision Dr Technology PkwyHarmony Rd Ziegler Rd
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B.DESCRIPTION OF PROPERTY
The project site currently exists as a vacant lot with native grasses and an existing imperviousness of approximately 2%. In
its existing (non-historic) condition, a minor portion of the site drains to the existing Harmony Commons Pond to the north
and a majority of the site drains to the southeast corner of the site to an existing drainage swale where it is collected by
existing storm sewer infrastructure and ultimately conveyed to another existing detention pond (Pond 110).
Below are summaries of key components of the site in its existing conditions.
Land Use - The site’s current land use is commercial.
Ground Cover - The site is currently covered with native grasses and weeds. The weed/grass cover is good (ie., heavy
or dense cover with nearly all ground surfaces protected by vegetation).
Existing Topography – Historically, the site slopes in two general directions: northerly and southeasterly. A majority
of the property drains to the southeast corner to existing storm sewer infrastructure located within Precision Drive,
and a minor portion of the property sheet flows to the north to the existing Harmony Commons Pond.
Grades – In general, the site is sloped southeasterly at approximately 0.5% to 2.0%; the southern portion of the site
is sloped northerly at approximately 0.5% to 2.0%. There is also a large drainage swale at the southeast corner with
slopes between 20% and 33%.
Soil Type - The USDA’s Web Soil Survey shows that the site consists of a “Type C” soil. The Web Soil Survey indicates
the site is comprised of Nunn Clay Loam (1 to 3% slopes). The on-site soils provide slow infiltration.
Utilities – Both wet and dry utilities are present in the Precision Drive right-of-way to the south of the site. Water,
storm, and sanitary mains are all present within Precision Drive while dry utilities including fiber, electric, and gas
are present in the south portion of the right-of-way of Precision Drive. There also appears to be gas and electric
lines near the southeast corner of the site in the adjacent property.
Drainage Features and Storm Sewer – Existing storm sewer is present at the southeast corner of the site as well as
within Precision Drive. Regional detention ponds also exist to the north and southeast which collect runoff from the
site.
C.FLOODPLAINS
The proposed development is not in a FEMA designated
or City Designated floodplain. According to the FEMA
Flood Insurance Rate Map Panel, the site is zoned as an
area outside of the 500-year floodplain. The FEMA FIRM
Map is included in the appendix.
II.DRAINAGE BASINS AND SUB-BASINS
A.MAJOR BASIN DESCRIPTION
The proposed development is located within the
McClellands Basin as delineated on the City of Fort Collins
Stormwater Basin Map. The site has also been previously
accounted for in the Harmony Technology Park Site
Master Plan Drainage Report as well as the Harmony
Technology Third Filing Drainage Study, and the proposed
development will be in conformance with both of these
studies. FIGURE 2:FLOODPLAIN MAP
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B.SUB-BASIN DESCRIPTION
The existing site is located within sub-basin 180 of the HTP Third Filing and SWMM Basin 100 and 601 of the HTP Site Master
Plan Drainage Report. The proposed site and project will be in conformance with both these reports. Improvements limited
to a storm sewer extension was also provided from the HTP Fourth Filing project to the east of the site.
In its developed condition, runoff from the site will largely be directed south and east to proposed bioretention ponds either
via overland flow to surface improvements or via proposed storm sewer. A portion of the site on the north and south sides
will drain to Precision Drive (south) and Harmony Commons Pond (north). Additionally, a minor portion of the site, largely
all pervious area, will continue to drain offsite to the west to existing bioretention ponds on the neighboring property.
III.DRAINAGE DESIGN CRITERIA
A.REGULATIONS
The design criteria for this study are directly from the City of Fort Collins Storm Drainage Design Criteria and Construction
Standards Manual and the Urban Storm Drainage Criteria Manuals Volumes 2, and 3 (referred to herein as USDCM).
B.DIRECTLY CONNECTED IMPERVIOUS AREA (DCIA)
With the adoption of the USDCM, the City has also adopted the “Four Step Process” that is recommended in Volume 3 of the
USDCM in selecting structural BMPs for the redeveloping urban areas. The following portions of this summary describe each
step and how it has been utilized for this project:
Step 1 – Employ Runoff Reduction Practices
The objective of this step is to reduce runoff peaks and volumes and to employ the technique of “minimizing directly
connected impervious areas” (MDCIA). This project accomplishes this by:
Routing the roof and pavement flows through a bioretention facility and vegetated swales to increase time of concentration,
promote infiltration and provide water quality.
Step 2 – Provide Water Quality Capture Volume (WQCV)
The objective of providing WQCV is to reduce the sediment load and other pollutants that exit the site. For this project WQCV
is provided within the existing regional ponds offsite. The site will, however, provide additional water quality to meet the
City’s Low Impact Development requirements through the use of onsite bioretention ponds.
Step 3 – Stabilize Drainageways
The site is not adjacent or near a major drainageway.
Step 4 – Consider Need for Site Specific and Source Control BMPs
Site specific and source control BMPs are generally considered for large industrial and commercial sites. The development
of the site will include multiple site specific and source controls, including:
Dedicated maintenance personnel providing landscape maintenance and snow and ice management.
C.HYDROLOGICAL CRITERIA
City of Fort Collins Rainfall Intensity-Duration-Frequency Curves, provided by Figure RA-16 of the Fort Collins Stormwater
Criteria Manual, are utilized for all hydrologic computations related to the site in its existing/historic and proposed conditions.
Since this site is relatively small and does not have complex drainage basins, the peak flow rates for design points have been
calculated based on the Rational Method as described in the USDCM and the City of Fort Collins Stormwater Criteria Manual
(FCSCM) with storm duration set equal to the time of concentration for each sub-basin. This method was used to analyze the
developed runoff from the 10-year (minor) and the 100-year (major) storm events. The Rational Method is widely accepted
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for drainage design involving small drainage areas (less than 160 acres) and short time of concentrations. Runoff coefficients
are assumed based on impervious area and are given in the Appendices.
D.HYDRAULIC CRITERIA
The developed site will convey runoff to the proposed pond or underground treatment facility via swales, concrete channels,
and pipes. The City of Fort Collins Stormwater Criteria Manual (FCSCM) and USDCM are referenced for all hydraulic
calculations. In addition, the following computer programs are utilized:
Storm Sewer Extension for AutoCAD Civil3D
Hydraflow Express Extension for AutoCAD Civil3D
UD-Inlet by UDFCD
Drainage conveyance facility capacities proposed with the development project, including storm sewer, swales, and inlet
capacities, are designed in accordance with criteria outlined in the FCSCM and/or the Urban Drainage and Flood Control
District’s Urban Storm Drainage Criteria Manual (UDFCD).
E.MODIFICATIONS OF CRITERIA
No drainage variances or modifications of drainage criteria are proposed for this project.
IV.DRAINAGE FACILITY DESIGN
A.GENERAL CONCEPT
Developed runoff is designed to be conveyed in a safe and effective manner via swales, concrete channels, and storm sewer
systems/inlets. Stormwater is designed to be released to either the Harmony Commons Pond to the north or existing
stormwater infrastructure in Precision Drive to the south and ultimately to Pond 110. Onsite runoff from the improved site
will be conveyed to bioretention ponds at the northeast and southeast corners of the site. Additionally, a minor portion of
the site, largely all pervious area, will continue to drain offsite to the west to existing bioretention ponds on the neighboring
property.
B.SPECIFIC DETAILS
Hydrology
As previously stated, hydrology from the developed site is designed to comply with criteria set forth in the City of Fort Collins
Stormwater Criteria Manual. Referenced tables, charts, formulas, etc. are included in the appendices. The area, time of
concentration, and runoff of each proposed sub-basin is summarized in Appendix A. The following information outlines the
basin characteristics and drainage patterns for each basin.
On-site Basins
The following basins provide proposed drainage delineations for the site in its improved condition. Refer to Appendix A for
hydrology computations and Appendix B for calculations related to Water Quality, Low Impact Development, and other
hydraulic features.
Basin A
Sub-basins A1-A6 (see Drainage Plan attached) are generally located around eastern region of the site while sub-basins A1.1-
A1.6 represent the east and north roof areas of the proposed building. These basins consist of roofs, concrete and asphalt
paving and landscaping. Runoff within these basins is conveyed to the bioretention pond via downspouts, inlets, curb and
gutter, and storm sewer. Runoff conveyed to the bioretention pond is discharged to the existing storm sewer stub from the
property to the east which is conveyed to the storm sewer system within Precision Drive and ultimately south to regional
detention Pond 110 at the intersection of Lady Moon Drive and Rock Creek Drive.
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Basin B
Sub-basins B1 and B1.1-B1.6 are generally located on the south side of the site. These sub-basins consist primarily of roofing,
concrete walks, and landscaped area. Runoff within these basins is conveyed to Precision via sheet flow and storm sewer/roof
drains.
Basin C
Basin C1 consists primarily of landscaped area and concrete pavement. Due to grading constraints, runoff developed within
this basin drains off-site undetained via sheet flow and ultimately to the existing bioretention pond southwest of the site.
The impervious area from Basin C1 is only 1,079 square feet (sidewalk) and no negative impacts are foreseen from this small
amount of additional impervious area being drained to the existing rain garden at the southeast corner of the neighboring
property to the east.
Basin D
Basin D1 consists primarily of landscaped area concrete pavement. Due to grading constraints, runoff developed within this
basin drains off-site undetained to the west via sheet flow and ultimately to the existing bioretention pond northwest of the
site. The impervious area from Basin D1 is approximately 1,943 square feet, of which 1,400 square feet is existing and is
accounted for in the existing bioretention pond; therefore, the additional impervious area generated from Basin D1 is only
543 square feet. Due to the minor increase in impervious area, no negative impacts are foreseen for this additional
impervious area draining to the existing rain garden at the northeast corner of the neighboring property to the west.
Basin E
Sub-basins E1-E2 are generally located around the north end of the site. These sub-basins consist of concrete and asphalt
paving and landscaping. Runoff within these basins drains off-site undetained to the north via sheet flow and ultimately to
the existing Harmony Commons Pond.
Detention and Water Quality
Water Quality
Standard water quality is provided for this site in the offsite regional detention ponds, Harmony Common Ponds to the north
and Pond 110 to the south of the site. The development of this site will require less water quality than originally assumed as
per the Regional Detention Pond Comparison Chart on the following page. Additional water quality per the City’s Low Impact
Development requirements will be provided on site. See Low Impact Development section later in the report.
Detention
Stormwater Detention is provided for this site in the offsite regional detention ponds, Harmony Common Ponds to the north
and Pond 110 to the south of the site. The development of this site will result in an increase of impervious area headed south
to Pond 110 but a small amount of detention will be provided on site in the bioretention to offset this area. The area draining
to the north to Harmony Commons pond has less impervious area than originally intended and will require less stormwater
detention than originally assumed, so no additional onsite detention is necessary for the north area.
The HTP Site Master Plan Drainage Report allows for a developed impervious value of up to 80% for the proposed site with
flow being released undetained from the site to Harmony Commons Pond (north) or Pond 110 (south). The HTP Site Master
Plan Drainage Report had accounted for approximately 0.78 acres of area from the proposed site draining to the north to
Harmony Commons Pond and 3.90 acres of area of the proposed site draining to the south to Pond 110. In its developed
condition, 4.36 acres of the site will drain to the south and 0.49 acres of the site will drain to the north. Although more area
and more impervious area will be draining to the south now, flow from the site will be constricted by the proposed outlet
structure which will detain stormwater and help offset the additional impervious area going to Pond 110 as well as pipe
capacities downstream of the site. Below is a comparison of the areas and imperviousness for the existing and proposed
basins.
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Regional Detention Pond Comparison Chart:
Pond Previously
Planned
Area (sf)
Proposed
Area (sf)
Master Plan
Proposed
Imperviousness
(%)
Developed
Imperviousness
(%)
Master Plan
Proposed Impervious
Area (Assumes 80%
Imperviousness)
Proposed
Impervious
Area (sf)
Harmony
Commons
(north)
34,035 21,358 80% 55.1% 27,228 11,567
Pond 110
(south)
169,668 189,796 80% 72.7% 135,734 137,981
The 100-year runoff from the HTP Site Master Plan Drainage Report for the developed site going to Pond 110 to the south
was calculated to be 9.05 cfs/acre. This is based on the 32.9 acres with a flow of 297.7 cfs for SWMM Basin 100 of the HTP
Site Master Plan Drainage Report. This correlates to a previously accounted release rate from the site of 35.25 cfs (3.90 acres
* 9.05 cfs/acre). The proposed 100-year flows from the site draining to the south (Basins A, B, and C) are currently at 28.45
cfs and below the previously accounted for release rate in the HTP Master Plan Report. This also does not consider that Basin
A flows will be reduced to 12 cfs in the 100-year storm through a restrictor plate in the outlet structure. With this restriction
included, the flows from the site in the 100-year event from the site draining to Pond 110 will be 16.45 cfs.
The 100-year runoff from the HTP Site Master Plan Drainage Report for the developed site going to the Harmony Commons
pond to the north was calculated to be 9.08 cfs/acre. This is based on the 29.0 acres with a flow of 263.44 cfs for SWMM
Basin 600 going to Pond 301 in the HTP Site Master Plan Drainage Report. This correlates to a previously accounted release
rate from the site of 7.08 cfs (0.78 acres * 9.08 cfs/acre). The proposed 100-year flows from the site draining to the north
(Basins D and E) are currently at 3.88 cfs and below the previously accounted for release rate in the HTP Master Plan Report.
Refer to the existing drainage exhibit in the appendix for more information on these areas and how the existing basin line
associates with the proposed site.
Low Impact Development (LID)
In December of 2015, Fort Collins City Council adopted the revised Low Impact Development (LID) policy and criteria which
requires developments within City limits to meet certain enhanced stormwater treatment requirements in addition to more
standard treatment techniques. The proposed development will be required to meet the newly adopted LID criteria which
requires the following:
-Treat no less than 75% of any newly added impervious area using one or a combination of LID techniques.
-Treat no less than 50% of any newly added impervious area using one or a combination of LID techniques when at
least 25% of any newly added pavement is provided with permeable pavement.
The following measures are implemented with this proposed development:
I.Bioretention
Bioretention is designed to remove sediment and pollution from stormwater runoff via infiltration through an
engineered sand media. This slows the conveyance rate of storm water runoff, reduces runoff and provides a flow
path across a vegetated surface. A bioretention pond is proposed with the site improvements and will be utilized to
convey and treat stormwater prior to release to Precision Drive.
Bioretention Pond
Sub-basins A1-A6 and A1.1-A1.6, with 121,393-sf of proposed impervious area, are designed to be conveyed to the
bioretention pond located at the southeast corner of the site. The proposed impervious area treated through this
bioretention pond includes proposed concrete and asphalt paving and roof areas in Basin A. Approximately 3,458-
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cf of volume in the bioretention pond, with up to one foot of depth, is designed specifically for water quality. This
volume slightly exceeds the required WQCV for Basin A (3,058-cf). Ponding above the initial one foot of depth will
be conveyed through an outlet structure to existing downstream storm sewer infrastructure. Additionally, an orifice
plat will be installed on the outlet structure to restrict flows from the site to 12 cfs in the 100-year event and allow
an additional 0.93 feet of ponding above the bioretention volume area.
The bioretention pond noted above treats approximately 75% of the proposed impervious area of the site. Refer to
Appendix B for calculations. Below is a summary of the bioretention pond:
Bottom of
Pond Elevation
Bioretention
WSEL
Bioretention
Volume Required
(cf)
Bioretention Volume
Provided
(cf)
Bioretention
Pond
4908.00 4909.00 3,058 3,458
Outlet Structure
A type C inlet will be used as an outlet structure at the southern end of the bioretention pond. Additionally, an orifice plate
will be provided on the existing 24” storm pipe to restrict site flows in the 100-year even to 12 cfs. By reducing flows from
the proposed site, pipe capacity for the overall system was improved and more capacity is provided for the Lot 1 of Harmony
Technology Park Fourth Filing property north of the Brinkman Construction property. In the 100-year event, the orifice plate
will restrict flows and allow 0.93 feet of ponding above the bioretention area and utilize the 8,5,32 cubic feet of volume
provided in the proposed pond area up to an elevation of 4909.93 feet with top of pond elevation being 4910.45 feet.
In the 100-year event, all stormwater will be conveyed through the outlet structure up to an elevation 4909.93 feet. Because
of this, no formal emergency overflow/spillway has been designed. However, there is a small area in the southern berm of
the pond that sits at an elevation of 4910.45 feet which is 0.52 feet below top of pond that will allow for water to spill south
which will only be utilized during an emergency situation. This water will pond between the property line and northern edge
of walk adjacent to Precision Drive before spilling over the walk and into Precision Drive to the east of the site.
By reducing flows from the Precision Technology site with the outlet structure and orifice plate, this provides additional
capacity in the storm sewer system downstream of the proposed site. This allows Lot 1 of Harmony Technology Park Fourth
Filing to discharge approximately 15 cfs to the existing storm sewer stub located on the south side of that lot.
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Drainage Summary
A basin summary table is included below:
Proposed Basins
Basin Area %I C2 C100 Q2 Q100
(acre) (cfs) (cfs)
A1 0.24 2% 0.25 0.31 0.16 0.71
A2 0.10 85% 0.85 1.00 0.25 1.04
A3 0.16 86% 0.86 1.00 0.40 1.62
A4 0.10 90% 0.95 1.00 0.28 1.01
A5 0.08 2% 0.25 0.31 0.05 0.23
A6 0.52 83% 0.84 1.00 1.15 5.14
A1.1 0.10 90% 0.95 1.00 0.27 1.00
A1.2 0.06 90% 0.95 1.00 0.16 0.58
A1.3 0.47 90% 0.95 1.00 1.26 4.63
A1.4 0.45 90% 0.95 1.00 1.21 4.43
A1.5 0.46 90%0.95 1.00 1.23 4.53
A1.6 0.50 90% 0.95 1.00 1.34 4.93
A Total 3.24 80% 0.85 1.00 5.16 21.10
B1 0.57 29%0.46 0.58 0.52 2.37
B1.1 0.08 90% 0.95 1.00 0.21 0.78
B1.2 0.15 90% 0.95 1.00 0.40 1.47
B1.3 0.10 90% 0.95 1.00 0.28 1.01
B1.4 0.06 90% 0.95 1.00 0.15 0.57
B1.5 0.06 90% 0.95 1.00 0.17 0.63
B Total 1.02 56% 0.68 0.84 1.74 6.82
C1 0.10 24% 0.42 0.53 0.12 0.53
D1 0.10 40% 0.55 0.69 0.16 0.71
E1 0.09 2% 0.25 0.31 0.06 0.28
E2 0.30 77% 0.78 0.98 0.66 2.88
E Total 0.39 59% 0.66 0.82 0.73 3.17
Proposed Total 4.85 71% 0.78 0.98 7.90 32.32
In its improved condition, the total site imperviousness is approximately 71% and well below the assumed 80% in the HTP
Site Master Plan Drainage Report; therefore, the site drainage is in compliance with the HTP Site Master Plan Drainage Report.
Standard Operating Procedures (SOPs)
In order for physical stormwater Best Management Practices (BMPs) to be effective, proper maintenance is essential.
Maintenance includes both routinely scheduled activities, as well as non-routine repairs that may be required after large
storms, or as a result of other unforeseen problems. Standard Operating Procedures should clearly identify BMP maintenance
responsibility. BMP maintenance is typically the responsibility of the entity owning the BMP.
Identifying who is responsible for maintenance of BMPs and ensuring that an adequate budget is allocated for maintenance
is critical to the long-term success of BMPs. Maintenance responsibility may be assigned either publicly or privately. For this
project, the privately owned BMPs including grass swales and the bioretention pond, are to be maintained by the property
owner.
Storm Sewers
There are multiple storm sewer networks proposed with the site improvements. Related to conveyance of runoff to the
bioretention pond, multiple roof drain systems are interconnected to storm sewer infrastructure which outfalls to the
bioretention pond. Additional roof drains on the south side of the site are interconnected as well but outfall to existing storm
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sewer within Precision Drive. All storm sewers will be private and are sized to accommodate the flows from the 100-year
storm event. Hydraulic computations of these systems are provided in the appendix.
Inlets
There are multiple inlets proposed with the site improvements, including Nyloplast (or similar) drain inlets, a Type C Inlet
used as the outlet structure and several combination inlets. The combination Inlets are designed in a sump condition to
capture runoff produced in Basins A2, A3, and A6. Other on-site drain inlets are designed in a sump condition and are designed
to convey runoff produced within smaller interior basins to the proposed storm sewer and bioretention ponds. The Type C
inlet will be used as an outlet structure for the proposed bioretention pond and will convey 100-yr storm events from the
pond to downstream storm sewer infrastructure. All inlets on the site are sized to provide adequate capacity and convey the
100-year storm event. Hydraulic computations of these systems will be provided with the initial final compliance submittal.
V.EROSION CONTROL
A separate Erosion Control Report / Storm Water Management Plan (SWMP) will be prepared for the site in accordance with
the Stormwater Discharge Permit for Colorado Department of Public Health and Environment as the site will disturb an area
greater than 1-acre. The Erosion Control Report will be completed during the Final Compliance phase of the project and will
include more detailed information on the sediment and erosion control items for this project. It is intended that the proposed
improvements will comply with Erosion Control Criteria per the FCSCM, and all Erosion Control Materials will be provided
with the Final Drainage Report. At a minimum, the following temporary BMP’s will be installed and maintained to control
on-site erosion and prevent sediment from traveling off-site during construction:
Silt Fence – a woven synthetic fabric that filters runoff. The silt fence is a temporary barrier that is placed at the base
of a disturbed area.
Vehicle Tracking Control – a stabilized stone pad located at points of ingress and egress on a construction site. The
stone pad is designed to reduce the amount of mud transported onto public roads by construction traffic.
Riprap – Riprap will be used downstream of all storm sewer outfalls to control erosion of the receiving channels.
Inlet Protection – acts as a sediment filter. It is a temporary BMP and requires proper installation and maintenance
to ensure their performance.
Straw Wattles – wattles act as a sediment filter in swales around inlets. They are a temporary BMP and require
proper installation and maintenance to ensure their performance.
The contractor shall store all construction materials and equipment and shall provide maintenance and fueling of equipment
in confined areas on-site from which runoff will be contained and filtered. Temporary Best Management Practices (BMP’s)
will be inspected by the contractor at a minimum of once every two weeks and after each significant storm event.
VI.CONCLUSIONS
A.COMPLIANCE WITH STANDARDS
Storm drainage calculations have followed the guidelines provided by the Urban Storm Drainage Criteria Manuals Volumes
1, 2 and 3 and the City of Fort Collins Stormwater Criteria Manual.
B.DRAINAGE CONCEPT
The drainage system has been designed to convey the runoff to the designated design points and the existing public
infrastructure and regional detention ponds in an effective, safe manner. No negative impacts are anticipated to the City of
Fort Collins Master Drainage Plan, to the HTP Site Master Plan, or to downstream properties or infrastructure due to the
proposed improvements.
F INAL D RAINAGE R EPORT
P RECISION T ECHNOLOGY
F ORT C OLLINS ,CO
10 U20015_Drainage Report
C.STORMWATER QUALITY
Multiple long-term stormwater quality measures have been selected for the site that will provide treatment of stormwater
prior it to being discharged from the site. For this site this includes a bioretention pond and offsite regional detention ponds
that include stormwater quality.
F INAL D RAINAGE R EPORT
P RECISION T ECHNOLOGY
F ORT C OLLINS ,CO
11 U20015_Drainage Report
VII.REFERENCES
1.City of Fort Collins Stormwater Criteria Manual, City of Fort Collins, Colorado, November 2017.
2.Urban Storm Drainage Criteria Manual Volume 1 and 2, Urban Drainage and Flood Control District, Denver, Colorado,
June 2001, Revised April 2008.
3.Final Drainage and Erosion Control Study for Harmony Technology Park Site Master Plan, Stantec, Fort Collins,
Colorado, May 2008.
4.Final Drainage and Erosion Control Study for Harmony Technology Park Third Filing, Stantec, Fort Collins, Colorado,
May 2008.
5.Final Drainage and Erosion Control Report for Harmony Technology Park Fourth Filing, Aspen Engineering, Fort Collins,
Colorado, January 2014.
6.Natural Resources Conservation Service Web Soil Survey at: websoilsurvey.nrcs.usda.gov/app
7.Preliminary Flood Insurance Rate Map, FEMA, Panel 0994F, https://hazards.fema.gov/femaportal/
8.Stormwater Discharges Associated with Construction Activity, Stormwater Management Plan Preparation Guides, State
of Colorado, www.colorado.com
A PPENDIX A
H YDROLOGY C ALCULATIONS
RUNOFF COEFFICIENTS AND % IMPERVIOUS
Precision Technology, Fort Collins, CO
Existing Basins
Basin Design Pt.Composite
Total Total Roof (1)Asphalt Concrete(1)Gravel(1)Lawns(3)Imperviousness C2 C100
acres sf %I = 90%%I = 100%%I = 90%%I =40%%I=2%
C=0.95 C=0.95 C=0.95 C=0.50 C=0.25
sf sf sf sf sf (%I)
A1 A1 0.24 10,667 ----10,667 2.0%0.25 0.31
A2 A2 0.10 4,567 -3,534 398 -636 85.5%0.85 1.00
A3 A3 0.16 7,110 -5,306 881 -923 86.0%0.86 1.00
A4 A4 0.10 4,433 904 -3,528 --90.0%0.95 1.00
A5 A5 0.08 3,674 ----3,674 2.0%0.25 0.31
A6 A6 0.52 22,482 -15,739 3,071 -3,672 82.6%0.84 1.00
A1.1 A1.1 0.10 4,390 4,390 ----90.0%0.95 1.00
A1.2 A1.2 0.06 2,529 2,529 ----90.0%0.95 1.00
A1.3 A1.3 0.47 20,260 20,260 ----90.0%0.95 1.00
A1.4 A1.4 0.45 19,409 19,409 ----90.0%0.95 1.00
A1.5 A1.5 0.46 19,853 19,853 ----90.0%0.95 1.00
A1.6 A1.6 0.50 21,591 21,591 ----90.0%0.95 1.00
A Total A Total 3.24 140,966 88,937 24,578 7,878 -19,572 79.5%0.85 1.00
B1 B1 0.57 24,966 -1,837 5,709 -17,420 29.3%0.46 0.58
B1.1 B1.1 0.08 3,399 3,399 ----90.0%0.95 1.00
B1.2 B1.2 0.15 6,420 6,420 ----90.0%0.95 1.00
B1.3 B1.3 0.10 4,429 4,429 ----90.0%0.95 1.00
B1.4 B1.4 0.06 2,484 2,484 ----90.0%0.95 1.00
B1.5 B1.5 0.06 2,755 2,755 ----90.0%0.95 1.00
B Total B Total 1.02 44,453 19,487 1,837 5,709 -17,420 55.9%0.68 0.84
C1 C1 0.10 4,377 --1,079 -3,298 23.7%0.42 0.53
D1 D1 0.10 4,486 --1,943 -2,543 40.1%0.55 0.69
E1 E1 0.09 3,962 ----3,962 2.0%0.25 0.31
E2 E2 0.30 12,910 -9,818 --3,092 76.5%0.78 0.98
E Total E Total 0.39 16,872 -9,818 --7,054 59.0%0.66 0.82
4.85 211,153 108,424 36,233 16,610 -49,887 70.9%0.78 0.98
Notes:
(1) Recommended % Imperviousness Values per Table 4.1-3 Surface Type - Percent Impervious in Fort Collins Stormwater Criteria Manual
(2) Runoff C is based Table 3.2-2. Surface Type - Runoff Coefficients and Table 3.2-3. Frequency Adjustment Factors in Fort Collins Stormwater Manual
(3) Runoff C for Lawns based off of Lawns, Clayey Soil, Avg Slope 2-7%
Proposed Total
Proposed Basins
Areas Composite Runoff Coefficients (2)
Date: 12/8/2020 C:\United Civil Dropbox\Projects\U20015 - PRCS Precision Tech II\Reports\Drainage\Calculations\U20015-Drain Calcs
2-YEAR TIME OF CONCENTRATION
Precision Technology, Fort Collins, CO
Existing Basins
Basin Design Pt.Area
C(1)Length Slope ti
(2)Length Slope Cv Velocity (3)tt
(4)Check tc?Total Length tc
(5)
acres ft %min ft %fps min min Urban?ft min min
A1 A1 0.24 0.25 22 5.0%4.2 149 0.5%20 1.4 1.8 6.0 Yes 171 11 6.0
A2 A2 0.10 0.85 41 2.0%2.3 118 3.0%20 3.5 0.6 2.8 Yes 159 11 5.0
A3 A3 0.16 0.86 24 2.0%1.7 147 2.0%20 2.8 0.9 2.6 Yes 171 11 5.0
A4 A4 0.10 0.95 37 5.0%1.0 50 0.5%20 1.4 0.6 1.6 Yes 87 10 5.0
A5 A5 0.08 0.25 25 2.0%6.1 150 2.0%15 2.1 1.2 7.3 Yes 175 11 7.3
A6 A6 0.52 0.84 60 2.0%2.9 297 0.5%20 1.4 3.5 6.4 Yes 357 12 6.4
A1.1 A1.1 0.10 0.95 68 2.1%1.7 1 33.0%20 11.5 0.0 1.7 Yes 69 10 5.0
A1.2 A1.2 0.06 0.95 66 2.1%1.7 1 33.0%20 11.5 0.0 1.7 Yes 67 10 5.0
A1.3 A1.3 0.47 0.95 156 2.1%2.6 1 33.0%20 11.5 0.0 2.6 Yes 157 11 5.0
A1.4 A1.4 0.45 0.95 146 2.1%2.6 1 33.0%20 11.5 0.0 2.6 Yes 147 11 5.0
A1.5 A1.5 0.46 0.95 138 2.1%2.5 1 33.0%20 11.5 0.0 2.5 Yes 139 11 5.0
A1.6 A1.6 0.50 0.95 128 2.1%2.4 1 33.0%20 11.5 0.0 2.4 Yes 129 11 5.0
A Routed A Routed 3.24 0.85 128 2.1%4.0 832 0.5%15 1.1 13.1 17.0 Yes 960 15 15.3
B1 B1 0.57 0.46 68 2.0%7.6 557 0.7%20 1.7 5.5 13.1 Yes 625 13 13.1
B1.1 B1.1 0.08 0.95 75 2.1%1.8 1 33.0%20 11.5 0.0 1.8 Yes 76 10 5.0
B1.2 B1.2 0.15 0.95 100 2.1%2.1 1 33.0%20 11.5 0.0 2.1 Yes 101 11 5.0
B1.3 B1.3 0.10 0.95 106 2.1%2.2 1 33.0%20 11.5 0.0 2.2 Yes 107 11 5.0
B1.4 B1.4 0.06 0.95 61 2.1%1.7 1 33.0%20 11.5 0.0 1.7 Yes 62 10 5.0
B1.5 B1.5 0.06 0.95 46 2.1%1.4 1 33.0%20 11.5 0.0 1.4 Yes 47 10 5.0
B Total B Total 1.02 0.68 -------
C1 C1 0.10 0.42 7 5.0%1.9 100 0.5%20 1.4 1.2 3.1 Yes 107 11 5.0
D1 D1 0.10 0.55 7 5.0%1.5 150 1.0%20 2.0 1.3 2.8 Yes 157 11 5.0
E1 E1 0.09 0.25 8 25.0%1.5 1 2.0%15 2.1 0.0 1.5 Yes 9 10 5.0
E2 E2 0.30 0.78 6 5.0%0.8 188 0.5%20 1.4 2.2 3.0 Yes 194 11 5.0
E Total E Total 0.39 0.66 -------
Notes:
(1) C=Cx*Cf
(2)ti = [1.87(1.1-CxCf)L1/2]/S1/3, S= slope in %, L=length of overland flow (300' max)
(3)V=CvS0.5, S=watercourse slope in ft/ft, UDFCD Equation RO-4
(4)tt=L/(V*60 sec/min)
(5)tc check (for urban or developed areas only) = total length/180 + 10
(6)min tc = 5 min
Proposed Basins
Travel/Channelized Time of Flow (tt)
ti+tt
tc Check for Urbanized Basins
Final tc
(6)
Date: 12/8/2020 C:\United Civil Dropbox\Projects\U20015 - PRCS Precision Tech II\Reports\Drainage\Calculations\U20015-Drain Calcs
100-YEAR TIME OF CONCENTRATION
Precision Technology, Fort Collins, CO
Existing Basins
Basin Design Pt.Area
C(1)Length Slope ti
(2)Length Slope Cv Velocity (3)tt
(4)Check tc?Total Length tc
(5)
acres ft %min ft %fps min min Urban?ft min min
A1 A1 0.24 0.31 22 5.0%3.9 149 0.5%20 1.4 1.8 5.7 Yes 171 11 5.7
A2 A2 0.10 1.00 41 2.0%0.9 118 3.0%20 3.5 0.6 1.5 Yes 159 11 5.0
A3 A3 0.16 1.00 24 2.0%0.7 147 2.0%20 2.8 0.9 1.6 Yes 171 11 5.0
A4 A4 0.10 1.00 37 5.0%0.6 50 0.5%20 1.4 0.6 1.2 Yes 87 10 5.0
A5 A5 0.08 0.31 25 2.0%5.7 150 2.0%15 2.1 1.2 6.8 Yes 175 11 6.8
A6 A6 0.52 1.00 60 2.0%1.1 297 0.5%20 1.4 3.5 4.6 Yes 357 12 5.0
A1.1 A1.1 0.10 1.00 68 2.1%1.2 1 33.0%20 11.5 0.0 1.2 Yes 69 10 5.0
A1.2 A1.2 0.06 1.00 66 2.1%1.1 1 33.0%20 11.5 0.0 1.1 Yes 67 10 5.0
A1.3 A1.3 0.47 1.00 156 2.1%1.8 1 33.0%20 11.5 0.0 1.8 Yes 157 11 5.0
A1.4 A1.4 0.45 1.00 146 2.1%1.7 1 33.0%20 11.5 0.0 1.7 Yes 147 11 5.0
A1.5 A1.5 0.46 1.00 138 2.1%1.7 1 33.0%20 11.5 0.0 1.7 Yes 139 11 5.0
A1.6 A1.6 0.50 1.00 128 2.1%1.6 1 33.0%20 11.5 0.0 1.6 Yes 129 11 5.0
A Routed A Routed 3.24 1.00 128 2.1%1.6 832 0.5%15 1.1 13.1 14.7 Yes 960 15 14.7
B1 B1 0.57 0.58 68 2.0%6.2 557 0.7%20 1.7 5.5 11.7 Yes 625 13 11.7
B1.1 B1.1 0.08 1.00 75 2.1%1.2 1 33.0%20 11.5 0.0 1.2 Yes 76 10 5.0
B1.2 B1.2 0.15 1.00 100 2.1%1.4 1 33.0%20 11.5 0.0 1.4 Yes 101 11 5.0
B1.3 B1.3 0.10 1.00 106 2.1%1.5 1 33.0%20 11.5 0.0 1.5 Yes 107 11 5.0
B1.4 B1.4 0.06 1.00 61 2.1%1.1 1 33.0%20 11.5 0.0 1.1 Yes 62 10 5.0
B1.5 B1.5 0.06 1.00 46 2.1%1.0 1 33.0%20 11.5 0.0 1.0 Yes 47 10 5.0
B Total B Total 1.02 0.84 0 0.0%-0 0.0%0 ------
C1 C1 0.10 0.53 7 5.0%1.6 100 0.5%20 1.4 1.2 2.8 Yes 107 11 5.0
D1 D1 0.10 0.69 7 5.0%1.1 150 1.0%20 2.0 1.3 2.4 Yes 157 11 5.0
E1 E1 0.09 0.31 8 25.0%1.4 1 2.0%15 2.1 0.0 1.4 Yes 9 10 5.0
E2 E2 0.30 0.98 6 5.0%0.3 188 0.5%20 1.4 2.2 2.5 Yes 194 11 5.0
E Total E Total 0.39 0.82 -------
Notes:
(1) C=Cx*Cf
(2)ti = [1.87(1.1-CxCf)L1/2]/S1/3, S= slope in %, L=length of overland flow (300' max)
(3)V=CvS0.5, S=watercourse slope in ft/ft, UDFCD Equation RO-4
(4)tt=L/(V*60 sec/min)
(5)tc check (for urban or developed areas only) = total length/180 + 10
(6)min tc = 5 min
Proposed Basins
Travel/Channelized Time of Flow (tt)
ti+tt
tc Check for Urbanized Basins
Final tc
(6)
Date: 12/8/2020 C:\United Civil Dropbox\Projects\U20015 - PRCS Precision Tech II\Reports\Drainage\Calculations\U20015-Drain Calcs
RATIONAL METHOD PEAK RUNOFF
Precision Technology, Fort Collins, CO
Existing Basins
Basin Design Pt.Area 2-Year 100-Year
acre tc tc C2 C100 I2 I100 Q2 Q100
min min in/hr in/hr cfs cfs
A1 A1 0.24 6 6 0.25 0.31 2.67 9.31 0.16 0.71
A2 A2 0.10 5 5 0.85 1.00 2.85 9.95 0.25 1.04
A3 A3 0.16 5 5 0.86 1.00 2.85 9.95 0.40 1.62
A4 A4 0.10 5 5 0.95 1.00 2.85 9.95 0.28 1.01
A5 A5 0.08 7 7 0.25 0.31 2.52 8.80 0.05 0.23
A6 A6 0.52 6 5 0.84 1.00 2.67 9.95 1.15 5.14
A1.1 A1.1 0.10 5 5 0.95 1.00 2.85 9.95 0.27 1.00
A1.2 A1.2 0.06 5 5 0.95 1.00 2.85 9.95 0.16 0.58
A1.3 A1.3 0.47 5 5 0.95 1.00 2.85 9.95 1.26 4.63
A1.4 A1.4 0.45 5 5 0.95 1.00 2.85 9.95 1.21 4.43
A1.5 A1.5 0.46 5 5 0.95 1.00 2.85 9.95 1.23 4.53
A1.6 A1.6 0.50 5 5 0.95 1.00 2.85 9.95 1.34 4.93
A Routed A Routed 3.24 15 15 0.85 1.00 1.87 6.52 5.16 21.10
B1 B1 0.57 13 12 0.46 0.58 1.98 7.16 0.52 2.37
B1.1 B1.1 0.08 5 5 0.95 1.00 2.85 9.95 0.21 0.78
B1.2 B1.2 0.15 5 5 0.95 1.00 2.85 9.95 0.40 1.47
B1.3 B1.3 0.10 5 5 0.95 1.00 2.85 9.95 0.28 1.01
B1.4 B1.4 0.06 5 5 0.95 1.00 2.85 9.95 0.15 0.57
B1.5 B1.5 0.06 5 5 0.95 1.00 2.85 9.95 0.17 0.63
B Total B Total 1.02 --0.68 0.84 --1.74 6.82
C1 C1 0.10 5 5 0.42 0.53 2.85 9.95 0.12 0.53
D1 D1 0.10 5 5 0.55 0.69 2.85 9.95 0.16 0.71
E1 E1 0.09 5 5 0.25 0.31 2.85 9.95 0.06 0.28
E2 E2 0.30 5 5 0.78 0.98 2.85 9.95 0.66 2.88
E Total E Total 0.39 --0.66 0.82 --0.73 3.17
7.90 32.32Totals
Proposed Basins
Runoff Coefficients Rainfall Intensity Peak Discharge
Date: 12/8/2020 C:\United Civil Dropbox\Projects\U20015 - PRCS Precision Tech II\Reports\Drainage\Calculations\U20015-Drain Calcs
A PPENDIX B
H YDRAULIC C ALCULATIONS
LOW IMPACT DEVELOPMENT SUMMARY
Precision Technology, Fort Collins, CO
Basin Proposed
Impervious Area
LID Treatment Area Treated % of Site Treated
(sf)(sf)(%)
A1 213 Bioretention Pond A 213 0%
A2 3,904 Bioretention Pond A 3,904 3%
A3 6,117 Bioretention Pond A 6,117 4%
A4 3,990 Bioretention Pond A 3,990 3%
A5 73 Bioretention Pond A 73 0%
A6 18,576 Bioretention Pond A 18,576 12%
A1.1 3,951 Bioretention Pond A 3,951 3%
A1.2 2,276 Bioretention Pond A 2,276 2%
A1.3 18,234 Bioretention Pond A 18,234 12%
A1.4 17,468 Bioretention Pond A 17,468 12%
A1.5 17,868 Bioretention Pond A 17,868 12%
A1.6 19,432 Bioretention Pond A 19,432 13%
A Total 112,103 Bioretention Pond A 112,103 75%
B1 7,323 None -0%
B1.1 3,059 None -0%
B1.2 5,778 None -0%
B1.3 3,986 None -0%
B1.4 2,236 None -0%
B1.5 2,480 None -0%
B Total 24,862 None -0%
C1 1,037 None -0%
D1 1,800 None -0%
E1 79 None -0%
E2 9,880 None -0%
E Total 9,959 None -0%
Total Site 149,761 112,103 75%
Low Impact Development (LID) Treated Areas
Date: 12/8/2020 C:\United Civil Dropbox\Projects\U20015 - PRCS Precision Tech II\Reports\Drainage\Calculations\U20015-Drain Calcs
WATER QUALITY - LOW IMPACT DEVELOPMENT
Precision Technology, Fort Collins, CO
Required Onsite Water Quality Capture Volume for LID
Basin Area Area Imperviousness Watershed WQCV*
(Extended Detention)
(sf)(acres)(%)(inches)(cf)
Basin A - Bioretention Pond
A1 10,667 0.245 2%0.01 11
A2 4,567 0.105 85%0.29 111
A3 7,110 0.163 86%0.30 175
A4 4,433 0.102 90%0.32 119
E2 12,910 0.296 77%0.25 265
A1.1 4,390 0.101 90%0.32 118
A1.2 2,529 0.058 90%0.32 68
A1.3 20,260 0.465 90%0.32 542
A1.4 19,409 0.446 90%0.32 519
A1.5 19,853 0.456 90%0.32 531
A1.6 21,591 0.496 90%0.32 578
A Total 140,966 3.236 80%0.26 3,058
Total WQ Provided onsite in Bioretention Pond 3,058
* Based on 12 hr storage forunderground detention
Date: 12/8/2020 C:\United Civil Dropbox\Projects\U20015 - PRCS Precision Tech II\Reports\Drainage\Calculations\U20015-Drain Calcs
DETENTION POND VOLUME (FAA Method)
Precision Technology, Fort Collins, CO
POND ID:Bioretention Pond
100 Year Storm Into Detention Facility
Area =140,966 square feet
Area =3.24 acres
C 100 = 1.00
Release Rate Out of Pond
Q OUT = 12.00 cfs
Unit Flow =3.71 cfs/acre
Notes:
1. Release Rate controlled by orifice plate in outlet structure.
2. Flowrate out of bioretention pond determined from allowable ponding volume in bioretention pond.
3. Pond is designed to provide WQ for all "A" Basins.
Detention Volume Calculations
Rainfall Rainfall Inflow Rate Inflow Volume Adjustment
Factor
Average Outflow Volume Required
Duration (T)Intensity (I)Qin= ∑C100*Area*I Vi=(Qin*T*60)Factor Outflow Rate Vo=Qav*T *60 Storage Volume
m= 0.5(1 + Tc/T) Qav = m*Qout Vs=Vi-Vo
min in/hr cfs ft 3 cfs ft 3 ft 3
5 9.95 32.2 9,660 1.00 12.00 3,600 6,060
10 7.72 25.0 14,990 1.00 12.00 7,200 7,790
15 6.52 21.1 18,990 1.00 12.00 10,800 8,190
20 5.60 18.1 21,747 1.00 12.00 14,400 7,347
25 4.98 16.1 24,174 1.00 12.00 18,000 6,174
30 4.52 14.6 26,329 1.00 12.00 21,600 4,729
35 4.08 13.2 27,727 1.00 12.00 25,200 2,527
40 3.74 12.1 29,047 1.00 12.00 28,800 247
45 3.46 11.2 30,232 1.00 12.00 32,400 -2,168
50 3.23 10.5 31,358 1.00 12.00 36,000 -4,642
55 3.03 9.8 32,358 1.00 12.00 39,600 -7,242
60 2.86 9.3 33,319 1.00 12.00 43,200 -9,881
70 2.59 8.4 35,203 1.00 12.00 50,400 -15,197
80 2.38 7.7 36,969 1.00 12.00 57,600 -20,631
90 2.21 7.2 38,620 1.00 12.00 64,800 -26,180
100 2.06 6.7 39,998 1.00 12.00 72,000 -32,002
110 1.94 6.3 41,435 1.00 12.00 79,200 -37,765
120 1.84 6.0 42,872 1.00 12.00 86,400 -43,528
Required Detention Volume
V 100 = 8,190 cubic feet
V 100 = 0.19 acre-ft
Date: 12/8/2020 C:\United Civil Dropbox\Projects\U20015 - PRCS Precision Tech II\Reports\Drainage\Calculations\U20015-Drain Calcs
DETENTION POND STORAGE AND ORIFICE CALCULATIONS
Precision Technology, Fort Collins, CO
POND ID:Bioretention Pond
Stage Storage Calculations
Elevation Area (sf)Depth (ft)
Incremental
Volume (cf)Volume total (cf)
Volume total (ac-
ft)
4,908.00 2,453.94 0.00 0 0 0.00
4,908.25 2,956.67 0.25 675 675 0.02
4,908.50 3,459.45 0.25 801 1,477 0.03
4,908.75 3,964.54 0.25 927 2,404 0.06
4,909.00 4,473.81 0.25 1,054 3,458 0.08
4,909.25 4,989.18 0.25 1,182 4,640 0.11
4,909.50 5,511.70 0.25 1,312 5,952 0.14
4,909.75 6,041.86 0.25 1,444 7,396 0.17
4,910.00 6,579.95 0.25 1,577 8,973 0.21
4,910.25 7,090.41 0.25 1,708 10,682 0.25
4,910.50 7,599.63 0.25 1,836 12,518 0.29
Detention Pond Storage & Water Quality
Detention Volume Required =8,190 ft3
0.19 ac-ft
Elev81 - Elev80 (VolRequired-Vol80)+Elev80
Vol81 - Vo80
Required W.S. Elevation = 4909.88 ft
Provided W.S. Elevation = 4909.93 ft
Detention Volume Provided =8,532 ft3
0.20 ac-ft
100-year Depth D = 6.09 ft
Top-of-Berm = 4910.45 ft
Freeboard = 0.52 ft
Orifice Opening and Water Quality Plate
Orifice Flow Rate, Q = CoAo(2gHo)0.5 cfs
Area of orifice Ao, ft2 = Q
Co(2gHo)0.5
C o = 0.65
Q = Q out of pond = 12.00 cfs
gravitational acceleration g = 32.2 ft/sec2
diam = 1.116 ft
Effective head on orifice H o = D-1/2diam =5.53 ft
Area of orifice A o = 0.98 ft2
Area of orifice A o = 140.85 in2
100-Year Orifice Diameter = 13.39 13 3/8 inches
100-Year Detention Volume and Elevations
W.S. Elevation, ft =
100-Year Orifice Calculation
Date: 12/8/2020 C:\United Civil Dropbox\Projects\U20015 - PRCS Precision Tech II\Reports\Drainage\Calculations\U20015-Drain Calcs
IINLET CAPACITY
Precision Technology, Fort Collins, CO
INLET ID:Pond Outlet Structure
Governing Equations:
Inlet capacity equation at low flows (weir calculation):
Where:
P = 2(L + W)
H = depth of water above the flowline
Inlet capacity equation at higher flows (orifice calculation):
Where:
A = open area of the inlet grate
H = depth of water above the centroid of the cross-sectional area (A)
Input Parameters:
Grate:Type C
Wier Perimeter:8.9
Open Area of Grate (ft2):9.4 Q100 = 12.00 cfs
Grate Centroid Elevation (ft):4909.00
Allowable Capacity:50%
Depth vs. Flow:
Depth Elevation Shallow Orifice Actual
Above Inlet Weir Flow Flow Flow
(ft)(ft)(cfs)(cfs)(cfs)
0.00 4909.00 0.00 0.00 0.00 <---- 10-Year Flow
0.05 4909.05 0.15 5.62 0.15
0.10 4909.10 0.42 7.95 0.42
0.15 4909.15 0.78 9.74 0.78
0.20 4909.20 1.20 11.25 1.20
0.25 4909.25 1.68 12.58 1.68
0.30 4909.30 2.20 13.78 2.20
0.35 4909.35 2.78 14.88 2.78
0.40 4909.40 3.39 15.91 3.39
0.45 4909.45 4.05 16.87 4.05
0.50 4909.50 4.74 17.78 4.74
0.55 4909.55 5.47 18.65 5.47
0.60 4909.60 6.23 19.48 6.23
0.65 4909.65 7.03 20.28 7.03
0.70 4909.70 7.85 21.04 7.85
0.75 4909.75 8.71 21.78 8.71
0.80 4909.80 9.60 22.50 9.60
0.85 4909.85 10.51 23.19 10.51
0.93 4909.93 12.00 24.24 12.00 <----100-Year Flow
0.95 4909.95 12.42 24.51 12.42
1.00 4910.00 13.41 25.15 13.41
5.10.3 HPQ
5.0)2(67.0 gHAQ
Calculations by: NKS
Date: 12/8/2020 C:\United Civil Dropbox\Projects\U20015 - PRCS Precision Tech II\Reports\Drainage\Calculations\U20015-Drain Calcs
Design Information (Input)MINOR MAJOR
Type of Inlet Type =
Local Depression (additional to continuous gutter depression 'a' from above)alocal =2.00 2.00 inches
Number of Unit Inlets (Grate or Curb Opening)No =1 1
Water Depth at Flowline (outside of local depression)Ponding Depth =5.7 5.7 inches
Grate Information MINOR MAJOR
Length of a Unit Grate Lo (G) =3.00 3.00 feet
Warning 5 Width of a Unit Grate Wo =1.73 1.73 feet
Area Opening Ratio for a Grate (typical values 0.15-0.90)Aratio =0.43 0.43
Clogging Factor for a Single Grate (typical value 0.50 - 0.70)Cf (G) =0.50 0.50
Grate Weir Coefficient (typical value 2.15 - 3.60)Cw (G) =3.30 3.30
Grate Orifice Coefficient (typical value 0.60 - 0.80)Co (G) =0.60 0.60
Curb Opening Information MINOR MAJOR
Length of a Unit Curb Opening Lo (C) =3.00 3.00 feet
Height of Vertical Curb Opening in Inches Hvert =6.50 6.50 inches
Height of Curb Orifice Throat in Inches Hthroat =5.25 5.25 inches
Angle of Throat (see USDCM Figure ST-5)Theta =0.00 0.00 degrees
Side Width for Depression Pan (typically the gutter width of 2 feet)Wp =1.00 1.00 feet
Clogging Factor for a Single Curb Opening (typical value 0.10)Cf (C) =0.10 0.10
Curb Opening Weir Coefficient (typical value 2.3-3.7)Cw (C) =3.70 3.70
Curb Opening Orifice Coefficient (typical value 0.60 - 0.70)Co (C) =0.66 0.66
Low Head Performance Reduction (Calculated)MINOR MAJOR
Depth for Grate Midwidth dGrate =0.430 0.430 ft
Depth for Curb Opening Weir Equation dCurb =0.40 0.40 ft
Combination Inlet Performance Reduction Factor for Long Inlets RFCombination =0.90 0.90
Curb Opening Performance Reduction Factor for Long Inlets RFCurb =1.00 1.00
Grated Inlet Performance Reduction Factor for Long Inlets RFGrate =0.90 0.90
MINOR MAJOR
Total Inlet Interception Capacity (assumes clogged condition)Qa =3.3 3.3 cfs
Inlet Capacity IS GOOD for Minor and Major Storms(>Q PEAK)Q PEAK REQUIRED =0.3 1.0 cfs
Warning 5: The width of unit is greater than the gutter width.
CDOT/Denver 13 Combination
INLET IN A SUMP OR SAG LOCATION
Version 4.06 Released August 2018
H-VertH-Curb
W
Lo (C)
Lo (G)
Wo
WP
CDOT/Denver 13 Combination
Override Depths
UD-Inlet_v4.06, Inlet A1 (Basin A2)12/8/2020, 6:19 PM
INLET A1 (BASIN A2)
Design Information (Input)MINOR MAJOR
Type of Inlet Type =
Local Depression (additional to continuous gutter depression 'a' from above)alocal =2.00 2.00 inches
Number of Unit Inlets (Grate or Curb Opening)No =1 1
Water Depth at Flowline (outside of local depression)Ponding Depth =6.0 6.0 inches
Grate Information MINOR MAJOR
Length of a Unit Grate Lo (G) =3.00 3.00 feet
Warning 5 Width of a Unit Grate Wo =1.73 1.73 feet
Area Opening Ratio for a Grate (typical values 0.15-0.90)Aratio =0.43 0.43
Clogging Factor for a Single Grate (typical value 0.50 - 0.70)Cf (G) =0.50 0.50
Grate Weir Coefficient (typical value 2.15 - 3.60)Cw (G) =3.30 3.30
Grate Orifice Coefficient (typical value 0.60 - 0.80)Co (G) =0.60 0.60
Curb Opening Information MINOR MAJOR
Length of a Unit Curb Opening Lo (C) =3.00 3.00 feet
Height of Vertical Curb Opening in Inches Hvert =6.50 6.50 inches
Height of Curb Orifice Throat in Inches Hthroat =5.25 5.25 inches
Angle of Throat (see USDCM Figure ST-5)Theta =0.00 0.00 degrees
Side Width for Depression Pan (typically the gutter width of 2 feet)Wp =1.00 1.00 feet
Clogging Factor for a Single Curb Opening (typical value 0.10)Cf (C) =0.10 0.10
Curb Opening Weir Coefficient (typical value 2.3-3.7)Cw (C) =3.70 3.70
Curb Opening Orifice Coefficient (typical value 0.60 - 0.70)Co (C) =0.66 0.66
Low Head Performance Reduction (Calculated)MINOR MAJOR
Depth for Grate Midwidth dGrate =0.451 0.451 ft
Depth for Curb Opening Weir Equation dCurb =0.42 0.42 ft
Combination Inlet Performance Reduction Factor for Long Inlets RFCombination =0.94 0.94
Curb Opening Performance Reduction Factor for Long Inlets RFCurb =1.00 1.00
Grated Inlet Performance Reduction Factor for Long Inlets RFGrate =0.94 0.94
MINOR MAJOR
Total Inlet Interception Capacity (assumes clogged condition)Qa =3.7 3.7 cfs
Inlet Capacity IS GOOD for Minor and Major Storms(>Q PEAK)Q PEAK REQUIRED =0.4 1.6 cfs
Warning 5: The width of unit is greater than the gutter width.
CDOT/Denver 13 Combination
INLET IN A SUMP OR SAG LOCATION
Version 4.06 Released August 2018
H-VertH-Curb
W
Lo (C)
Lo (G)
Wo
WP
CDOT/Denver 13 Combination
Override Depths
UD-Inlet_v4.06, Inlet B1 (Basin A3)12/8/2020, 6:19 PM
INLET B1 (BASIN A3)
Design Information (Input)MINOR MAJOR
Type of Inlet Type =
Local Depression (additional to continuous gutter depression 'a' from above)alocal =2.00 2.00 inches
Number of Unit Inlets (Grate or Curb Opening)No =2 2
Water Depth at Flowline (outside of local depression)Ponding Depth =6.0 6.0 inches
Grate Information MINOR MAJOR
Length of a Unit Grate Lo (G) =3.00 3.00 feet
Warning 5 Width of a Unit Grate Wo =1.73 1.73 feet
Area Opening Ratio for a Grate (typical values 0.15-0.90)Aratio =0.43 0.43
Clogging Factor for a Single Grate (typical value 0.50 - 0.70)Cf (G) =0.50 0.50
Grate Weir Coefficient (typical value 2.15 - 3.60)Cw (G) =3.30 3.30
Grate Orifice Coefficient (typical value 0.60 - 0.80)Co (G) =0.60 0.60
Curb Opening Information MINOR MAJOR
Length of a Unit Curb Opening Lo (C) =3.00 3.00 feet
Height of Vertical Curb Opening in Inches Hvert =6.50 6.50 inches
Height of Curb Orifice Throat in Inches Hthroat =5.25 5.25 inches
Angle of Throat (see USDCM Figure ST-5)Theta =0.00 0.00 degrees
Side Width for Depression Pan (typically the gutter width of 2 feet)Wp =1.00 1.00 feet
Clogging Factor for a Single Curb Opening (typical value 0.10)Cf (C) =0.10 0.10
Curb Opening Weir Coefficient (typical value 2.3-3.7)Cw (C) =3.70 3.70
Curb Opening Orifice Coefficient (typical value 0.60 - 0.70)Co (C) =0.66 0.66
Low Head Performance Reduction (Calculated)MINOR MAJOR
Depth for Grate Midwidth dGrate =0.451 0.451 ft
Depth for Curb Opening Weir Equation dCurb =0.42 0.42 ft
Combination Inlet Performance Reduction Factor for Long Inlets RFCombination =0.71 0.71
Curb Opening Performance Reduction Factor for Long Inlets RFCurb =1.00 1.00
Grated Inlet Performance Reduction Factor for Long Inlets RFGrate =0.71 0.71
MINOR MAJOR
Total Inlet Interception Capacity (assumes clogged condition)Qa =5.6 5.6 cfs
Inlet Capacity IS GOOD for Minor and Major Storms(>Q PEAK)Q PEAK REQUIRED =1.2 5.1 cfs
Warning 5: The width of unit is greater than the gutter width.
CDOT/Denver 13 Combination
INLET IN A SUMP OR SAG LOCATION
Version 4.06 Released August 2018
H-VertH-Curb
W
Lo (C)
Lo (G)
Wo
WP
CDOT/Denver 13 Combination
Override Depths
UD-Inlet_v4.06, Inlet C2-1(E) (Basin A6)12/8/2020, 6:19 PM
INLET C21(E) (BASIN A6)
A PPENDIX C
R EFERENCED M ATERIALS
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United States
Department of
Agriculture
A product of the National
Cooperative Soil Survey,
a joint effort of the United
States Department of
Agriculture and other
Federal agencies, State
agencies including the
Agricultural Experiment
Stations, and local
participants
Custom Soil Resource
Report for
Larimer County
Area, Colorado
Precision Tech II
Natural
Resources
Conservation
Service
August 4, 2020
9
Custom Soil Resource Report
Soil Map
4485220448524044852604485280448530044853204485340448536044852204485240448526044852804485300448532044853404485360498770 498790 498810 498830 498850 498870 498890 498910 498930 498950 498970 498990
498770 498790 498810 498830 498850 498870 498890 498910 498930 498950 498970 498990
40° 31' 8'' N 105° 0' 52'' W40° 31' 8'' N105° 0' 42'' W40° 31' 3'' N
105° 0' 52'' W40° 31' 3'' N
105° 0' 42'' WN
Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 13N WGS84
0 50 100 200 300
Feet
0 15 30 60 90
Meters
Map Scale: 1:1,090 if printed on A landscape (11" x 8.5") sheet.
Soil Map may not be valid at this scale.
MAP LEGEND MAP INFORMATION
Area of Interest (AOI)
Area of Interest (AOI)
Soils
Soil Map Unit Polygons
Soil Map Unit Lines
Soil Map Unit Points
Special Point Features
Blowout
Borrow Pit
Clay Spot
Closed Depression
Gravel Pit
Gravelly Spot
Landfill
Lava Flow
Marsh or swamp
Mine or Quarry
Miscellaneous Water
Perennial Water
Rock Outcrop
Saline Spot
Sandy Spot
Severely Eroded Spot
Sinkhole
Slide or Slip
Sodic Spot
Spoil Area
Stony Spot
Very Stony Spot
Wet Spot
Other
Special Line Features
Water Features
Streams and Canals
Transportation
Rails
Interstate Highways
US Routes
Major Roads
Local Roads
Background
Aerial Photography
The soil surveys that comprise your AOI were mapped at
1:24,000.
Warning: Soil Map may not be valid at this scale.
Enlargement of maps beyond the scale of mapping can cause
misunderstanding of the detail of mapping and accuracy of soil
line placement. The maps do not show the small areas of
contrasting soils that could have been shown at a more detailed
scale.
Please rely on the bar scale on each map sheet for map
measurements.
Source of Map: Natural Resources Conservation Service
Web Soil Survey URL:
Coordinate System: Web Mercator (EPSG:3857)
Maps from the Web Soil Survey are based on the Web Mercator
projection, which preserves direction and shape but distorts
distance and area. A projection that preserves area, such as the
Albers equal-area conic projection, should be used if more
accurate calculations of distance or area are required.
This product is generated from the USDA-NRCS certified data as
of the version date(s) listed below.
Soil Survey Area: Larimer County Area, Colorado
Survey Area Data: Version 15, Jun 9, 2020
Soil map units are labeled (as space allows) for map scales
1:50,000 or larger.
Date(s) aerial images were photographed: Aug 11, 2018—Aug
12, 2018
The orthophoto or other base map on which the soil lines were
compiled and digitized probably differs from the background
imagery displayed on these maps. As a result, some minor
shifting of map unit boundaries may be evident.
Custom Soil Resource Report
10
Map Unit Legend
Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI
74 Nunn clay loam, 1 to 3 percent
slopes
4.5 100.0%
Totals for Area of Interest 4.5 100.0%
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
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
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 content:7 percent
Maximum salinity:Nonsaline to very slightly saline (0.1 to 2.0 mmhos/cm)
Sodium adsorption ratio, maximum:0.5
Available water capacity:High (about 9.9 inches)
Interpretive groups
Land capability classification (irrigated): 2e
Land capability classification (nonirrigated): 3e
Hydrologic Soil Group: C
Ecological site: R067BY042CO - Clayey Plains
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:R067BY042CO - Clayey Plains
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:R067BY002CO - Loamy Plains
Hydric soil rating: No
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
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
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A PPENDIX D
D RAINAGE E XHIBITS
PREVIOUSLY ACCOUNTED FOR AREA IN HTP SITE MASTER PLAN
DRAINAGE REPORT FOR PRECISION TECHNOLOGY SITE
DRAINING NORTH TO HARMONY COMMONS POND = 0.78 ACRES
PREVIOUSLY ACCOUNTED FOR AREA IN HTP SITE MASTER PLAN
DRAINAGE REPORT FOR PRECISION TECHNOLOGY SITE
DRAINING SOUTH TO POND 110 = 3.90 ACRES
0'30'60'
SCALE: 1" = 30'
15'C:\UNITED CIVIL DROPBOX\PROJECTS\U20015 - PRCS PRECISION TECH II\CADD\IMAGES\DRAINAGE FIGURES\EX DRAINAGE EXHIBIT.DWGEX DRAINAGE EXHIBITPATH:DRAWING NAME:SHEET SIZE: 24x 36PRECISION TECHNOLOGY
EXISTING DRAINAGE CONVEYANCE AREAS EXHIBIT
DATE:August 26, 2020 PREPARED FOR:PRECISION TECHNOLOGY LLC JOB NUMBER:U20015 NOTE:THIS EXHIBIT WAS PREPARED FOR INFORMATION ONLY AND THE ENGINEER PREPARING THESE PLANS WILL NOT BE RESPONSIBLE FOR UNAUTHORIZED USE OF THEM.TIME:4:43:23 PM
1501 ACADEMY COURT, SUITE 203 FORT COLLINS, CO 80524
(970) 530-4044 WWW.UNITEDCIVIL.COM
SHEET OF1 1
UNITED CIVIL
Design Group LLC
NORTH
PROPOSED AREA FROM PRECISION TECHNOLOGY SITE
DRAINING SOUTH TO POND 110 = 4.24 ACRES
PROPOSED AREA FROM PRECISION TECHNOLOGY SITE
DRAINING NORTH TO HARMONY COMMONS POND = 0.43 ACRES
0'30'60'
SCALE: 1" = 30'
15'C:\UNITED CIVIL DROPBOX\PROJECTS\U20015 - PRCS PRECISION TECH II\CADD\IMAGES\DRAINAGE FIGURES\EX DRAINAGE EXHIBIT.DWGEX DRAINAGE EXHIBITPATH:DRAWING NAME:SHEET SIZE: 24x 36PRECISION TECHNOLOGY
PROPOSED DRAINAGE CONVEYANCE AREAS EXHIBIT
DATE:August 26, 2020 PREPARED FOR:PRECISION TECHNOLOGY LLC JOB NUMBER:U20015 NOTE:THIS EXHIBIT WAS PREPARED FOR INFORMATION ONLY AND THE ENGINEER PREPARING THESE PLANS WILL NOT BE RESPONSIBLE FOR UNAUTHORIZED USE OF THEM.TIME:4:43:23 PM
1501 ACADEMY COURT, SUITE 203 FORT COLLINS, CO 80524
(970) 530-4044 WWW.UNITEDCIVIL.COM
SHEET OF1 1
UNITED CIVIL
Design Group LLC
NORTH
RDRDRDRDRDRDRDRDRDOVFRDA1.60.500.951.00A1.50.460.951.00A1.40.450.951.00A1.30.470.951.00A1.20.060.951.00A1.10.100.951.00B1.10.080.951.00B1.20.150.951.00B1.30.100.951.00B1.40.060.951.00B1.50.060.951.00A40.100.951.00A30.160.861.00A20.100.851.00A10.240.250.31D10.100.550.69E10.090.250.31E20.300.780.98A60.520.841.00A50.080.250.31B10.570.460.58C10.100.420.53LOT 2HARMONY TECHNOLOGY PARKFIFTH FILINGLOT 1HARMONY TECHNOLOGY PARKFOURTH FILINGPORTION OF LOT 2HARMONY TECHNOLOGY PARKSECOND FILINGTRACT AHARMONY TECHNOLOGY PARKSIXTH FILINGLOT 1HARMONY TECHNOLOGY PARKFIFTH FILINGPRECISION DRIVEPROPOSED BUILDIINGFFE = 4916.50EXISTING STORM SEWERLOT LINELOT LINELOT LINELOT LINEPOND OUTLET STRUCTUREBIORETENTION POND A
DRAINAGE SWALE1.5' SPILL C&G1.5' CATCH C&G1.5' SPILL C&G1.5' CATCH C&GSTORM LINE B(SEE SHEET C3.10)STORM LINE C(SEE SHEET C3.11)1.5' SPILL C&G1.5' CATCH C&GCURB CUTSTORM LINE D(SEE SHEET C3.12)TRENCH DRAINSTORM LINE C2(SEE SHEET C3.10)EXISTING BIORETENTION POND9' UTILITY EASEMENT30' UTILITY & DRAINAGE EASEMENT45' UTILITY & DRAINAGEEASEMENTDRAINAGE EASEMENT24' EMERGENCY ACCESS EASEMENT24' EMERGENCY ACCESS EASEMENTDRAINAGE EASEMENTDRAINAGE EASEMENTCURB CUT64' ROW20' UTILITY EASEMENT24' EMERGENCY ACCESS EASEMENTDRAINAGE EASEMENTSTORM LINE A(SEE SHEET C3.10)STORM LINE E(SEE SHEET C3.12)PRECISION TECHNOLOGY LLC 12/09/2020U200151" = 30'1" = N/APRECISION TECHNOLOGY
NORTH
12/8/2020 2:49:18 PMC:\UNITED CIVIL DROPBOX\PROJECTS\U20015 - PRCS PRECISION TECH II\CADD\CP\C5.00 - DRAINAGE PLAN.DWGC5.00 - DRAINAGE PLAN SME NKS
C5.0024DRAINAGE PLAN030'60'SCALE: 1" = 30'15'PREPARED FOR:JOB NUMBERSHEET NUMBERSHEETSOFDATE SUBMITTED:VERTICAL:HORIZONTAL:SCALEPR
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PROJ. MGR:DRAWING NAME:PATH:DESIGNER:DATE:TIME:
The engineer preparing these plans will not be responsible for, or liable for, unauthorized
changes to or uses of these plans. All changes to the plans must be in writing and must
be approved by the preparer of these plans.
NO.BY DATE
CAUTIONREVISIONS:CIVIL ENGINEERING & CONSULTINGUNITED CIVILDesign Group19 OLD TOWN SQUARE #238FORT COLLINS, CO 80524(970) 530-4044www.unitedcivil.com13X.XXX.XXXX.XXBASIN DESIGNATIONBASIN AREA (ACRE)5 - YR RUNOFF COEFF.100 - YR RUNOFF COEFF.DESIGN POINTFLOW DIRECTIONDPD1LEGEND1.EXISTING UNDERGROUND AND OVERHEAD PUBLIC AND PRIVATEUTILITIES AS SHOWN ARE INDICATED ACCORDING TO THE BESTINFORMATION AVAILABLE TO THE ENGINEER.2.VEGETATIVE SWALES, BIOSWALES, AND THE BIORETENTION PONDSSHALL BE MAINTAINED BY THE PROPERTY OWNER AND FOLLOWAPPLICABLE STANDARD OPERATING PROCEDURES AS SHOWN INDEVELOPMENT AGREEMENT.3.SEE GRADING PLANS (SHEET C4.00) FOR MORE DETAIL ON PONDAND SITE GRADING.NOTESCHECKED BY:CHECKED BY:CHECKED BY:CHECKED BY:CHECKED BY:APPROVED:DRAINAGE SUMMARYPOND SUMMARYLOW IMPACT DEVELOPMENT TREATMENT SUMMARYBioretention PondLID WQCV REQUIRED3,058 CFLID WQCV PROVIDED3,458 CFBOTTOM OF POND ELEVATION4,908.00LID WQCV WATER SURFACE ELEVATION4,909.00100-YEAR WATER SURFACE ELEVATION4,910.00TOP OF POND ELEVATION4,910.64Proposed BasinsBasinArea%IC2C100Q2Q100(acre)(cfs)(cfs)A10.242%0.250.310.160.71A20.1085%0.851.000.251.04A30.1686%0.861.000.401.62A40.1090%0.951.000.281.01A50.082%0.250.310.050.23A60.5283%0.841.001.155.14A1.10.1090%0.951.000.271.00A1.20.0690%0.951.000.160.58A1.30.4790%0.951.001.264.63A1.40.4590%0.951.001.214.43A1.50.4690%0.951.001.234.53A1.60.5090%0.951.001.344.93A Total3.2480%0.851.005.1621.10B10.5729%0.460.580.522.37B1.10.0890%0.951.000.210.78B1.20.1590%0.951.000.401.47B1.30.1090%0.951.000.281.01B1.40.0690%0.951.000.150.57B1.50.0690%0.951.000.170.63B Total1.0256%0.680.841.746.82C10.1024%0.420.530.120.53D10.1032%0.550.690.140.63E10.092%0.250.310.060.28E20.3077%0.780.980.662.88E Total0.3959%0.660.820.733.17Proposed Total4.8571%0.780.987.9032.32BasinProposedImperviousArea (sf)LID TreatmentArea Treated(sf)% of SiteTreated (%)A1213Bioretention Pond2130%A23,904Bioretention Pond3,9043%A36,117Bioretention Pond6,1174%A43,990Bioretention Pond3,9903%A573Bioretention Pond730%A618,576Bioretention Pond18,57612%A1.13,951Bioretention Pond3,9513%A1.22,276Bioretention Pond2,2762%A1.318,234Bioretention Pond18,23412%A1.417,468Bioretention Pond17,46812%A1.517,868Bioretention Pond17,86812%A1.619,432Bioretention Pond19,43213%A Total112,103Bioretention Pond112,10375%B17,323None00%B1.13,059None00%B1.25,778None00%B1.33,986None00%B1.42,236None00%B1.52,480None00%B Total24,862None00%C11,037None00%D11,800None00%E179None00%E29,880None00%E Total9,959None00%Total Site149,411112,10375%