HomeMy WebLinkAbout2620 W. ELIZABETH ST., SINGLE-FAMILY DETACHED - PDP - PDP160037 - SUBMITTAL DOCUMENTS - ROUND 2 - DRAINAGE REPORTPRELIMINARY DRAINAGE REPORT
Elizabeth Street Farms
Fort Collins, Colorado
Prepared for:
High Plains Builders, LLC
P.O. Box 2796
Gillette, Wyoming 82717
Phone: (307) 257-2352
Prepared by:
Galloway & Company, Inc.
3760 East 15th Street, Suite 202
Loveland, Colorado 80538
Phone: (970) 800-3300
Contact: Herman Feissner, PE
Original Preparation: November 2nd, 2016
Revised: July 12th, 2017
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TABLE OF CONTENTS
TABLE OF CONTENTS.......................................................................................................................... 1
I. CERTIFICATIONS .......................................................................................................................... 2
II. GENERAL LOCATION AND DESCRIPTION .................................................................................. 3
III. DRAINAGE BASINS AND SUB-BASINS ........................................................................................ 5
IV. DRAINAGE DESIGN CRITERIA ..................................................................................................... 5
V. DRAINAGE FACILITY DESIGN .................................................................................................... 10
VI. EROSION AND SEDIMENT CONTROL MEASURES ................................................................... 12
VII. CONCLUSIONS ............................................................................................................................ 13
VIII. REFERENCES .............................................................................................................................. 14
APPENDIX A - REFERENCE MATERIALS
VICINITY MAP
NRCS SOILS MAP
FEMA FIRMETTE
CITY OF FORT COLLINS FLOOD MAPPING
APPENDIX B - HYDROLOGY CALCULATIONS
EXISTING RUNOFF CALCULATIONS
PROPOSED RUNOFF CALCULATIONS
APPENDIX C - HYDRAULIC CALCULATIONS
SWALE CAPACITY CALCULATIONS
PRELIMINARY DETENTION POND SIZING
APPENDIX D – DRAINAGE MAPS
EXISTING CONDITION DRAINAGE MAP
DEVELOPED CONDITION DRAINAGE MAP
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I. CERTIFICATIONS
CERTIFICATION OF ENGINEER
“I hereby certify that this report for the final drainage design of Elizabeth Street Farms was
prepared by me (or under my direct supervision) in accordance with the provisions of the Fort
Collins Stormwater Criteria Manual for the owners thereof.”
______________________________________
Herman Feissner, PE
Registered Professional Engineer
State Of Colorado No. 38066
For and on behalf of Galloway & Company, Inc.
CERTIFICATION OF OWNER
“High Plains Builders, LLC hereby certifies that the drainage facilities for the Elizabeth Street
Farms be constructed according to the design presented in this report. We understand that the
City of Fort Collins does not and will not assume liability for drainage facilities designed and/or
certified by our engineer. We also understand that the City of Fort Collins relies on the
representation of others to establish that drainage facilities are designed and constructed in
compliance with City of Fort Collins guidelines, standards, or specifications. Review by the City
of Fort Collins can therefore in no way limit or diminish any liability, which we or any other party
may have with respect to the design or construction of such facilities.”
____________________________________
High Plains Builders, LLC
Attest:
___________________________________
(Name of Responsible Party)
__________________________________
Notary Public
__________________________________
Authorized Signature
STAMP AND SIGNATURE WITH APPROVAL OF FINAL DRAINAGE REPORT
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II. GENERAL LOCATION AND DESCRIPTION
LOCATION
Elizabeth Street Farms (hereafter referred to as “the site” or “project site”) is located at 2620
West Elizabeth Street. The site is bounded on north by single-family residential development
and Pear Street right-of-way (existing cul-de-sac); on the south by West Elizabeth Street; and
on the east and west by single-family residential. More specifically, the site is Tract A of West
Plum Street – a Planned Unit Development situate in the north half of Section 16, Township 7
north, Range 69 west of the 6th Principal Meridian, City of Fort Collins, County of Larimer, State
of Colorado. Refer to Appendix A for a vicinity map.
DESCRIPTION OF PROPERTY
The project site consists of ±2.56 acres. It is largely vacant and undeveloped. Previously the
site was used for agriculture. An existing two-story brick house, which the developer plans to
restore, is located in the southeast region of the site. An existing irrigation lateral, which is still
in use, crosses the site from west to east. The existing grades average between 0.50% and
1.00%. Locally steeper grades exist along the irrigation lateral and around the existing house.
The existing runoff flows from northwest to southeast. An existing swale along the north edge
of West Elizabeth Street captures existing runoff and conveys it east.
There are no major drainage ways passing through the project site.
According to the USDA NRCS Web Soil Survey, ‘Altvan-Satanta loams, 0 to 3 percent slopes’
covers roughly one-third of the project site. The remaining two-thirds of the site are ‘Altvan-
Satanta loams, 3 to 9 percent slopes’. These soils are associated with Hydrologic Soil Group
(HSG) ‘B’. HSG ‘B’ soils have a moderate infiltration rate when thoroughly wet. These consist
chiefly of moderately deep or deep, moderately well drained or well drained soils that have
moderately fine texture to moderately coarse texture. These soils have a moderate rate of
water transmission. Refer to Appendix A for additional soils information.
Hollingsworth Associates, Inc. conducted a subsurface study the project site. The results of the
preliminary geotechnical investigation are summarized in Subsurface Study for Ten Lots West
Elizabeth Subdivision Fort Collins, Colorado (Job No.: 16-469 | Dated: October 12, 2016). The
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subsurface conditions across the lots were quite uniform, as indicated by exploratory borings
B-1 through B-5, and consisted of 12 inches of topsoil, 2 to 11 feet of medium stiff to stiff
sandy clay, which occasionally graded into clayey sand, and 2 feet to 5 feet of firm to medium
hard, interlayered and integrated weathered claystone/sandstone overlaying hard to very hard
claystone for the depth drilled, 21 feet.
The site is situated east of the Pleasant Valley and Lake Canal. An operational west-to-east
irrigation lateral flows across the project site. According to the ditch rider, Ed Wendel, five
people currently receive water from the lateral.
Elizabeth Street Farms will develop in a single phase as single-family residential. The project
includes the development of eight (8) single-family lots, street improvements, wet and dry utility
infrastructure and landscaping. A single point of access will be provided to the project site from
Pear Street.
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III. DRAINAGE BASINS AND SUB-BASINS
MAJOR BASIN DESCRIPTION
The project site is located in the Canal Importation drainage basin. According to the City of
Fort Collins website (www.fcgov.com), this basin “spans nearly five square miles in west-central
Fort Collins. Three major irrigation canals traverse the basin from north to south and impact the
drainage in the basin. The canals can intercept runoff traveling through the basin and transport
it out of the basin, and they also spill runoff into the basin when their capacity is exceeded”.
SUB- BASIN DESCRIPTION
The project site generally conforms to the input parameters of SWMM subbasin 9 in the Canal
Importation drainage basin. SWMM subbasin 9 is 60% impervious. It generally drains to
Elizabeth Street and then east. The proposed site will be ±50% impervious. The runoff
ultimately drains into the Red Fox Meadows neighborhood natural area.
The project site is shown on FEMA Map Numbers 08069C0960F and 08069C0978G (refer to
Appendix A for FEMA Firmettes). Neither map shows the project impacted by an existing
floodplain/floodway. Refer to Appendix A for a copy of each Firmette and a copy of the City of
Fort Collins flood map.
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IV. DRAINAGE DESIGN CRITERIA
REGULATIONS
This preliminary drainage design presented herein was prepared in accordance with the Fort
Collins Amendments to the Urban Drainage and Flood Control District Criteria Manual (i.e.,
Urban Drainage and Flood Control District Urban Storm Drainage Criteria Manuals Volumes 1,
2 and 3 [Manual]). Together, the requirements are referred to as the Fort Collins Stormwater
Criteria Manual [FCSCM].
DIRECTLY CONNECTED IMPERVIOUS AREA (DCIA)
The project site is encumbered by several constraints; therefore, we developed a strategy for
implementing ‘The Four-Step Process’ for stormwater quality management to the Maximum
Extent Practicable (MEP). Each step is listed below along with a brief narrative describing the
implementation strategy.
Step 1 - Employ runoff reduction practices
The developed runoff from the A, B and C series of basins flow through vegetated swales
before entering the on-site detention facility. The UDFCD defines a Grass Swale as “Densely
vegetated drainage way with low-pitched side slopes that collects and slowly conveys runoff.
The design of the longitudinal slope and cross-section size forces the flow to be slow and
shallow, thereby facilitating sedimentation while limiting erosion.” The proposed vegetated
swales will have low longitudinal slopes of ±0.50%. It is designed to convey 2-year storm event
runoff in a slow (i.e., <1 ft/sec) and shallow manner (i.e., normal depth <1 foot). This design
encourages settling and infiltration.
Of the newly added impervious area, ±1.02 acres are tributary to vegetated swales. Impervious
areas have been disconnected to the Maximum Extent Practicable. (MEP)
Step 2 - Implement BMPs that provide a Water Quality Capture Volume (WQCV)
The proposed BMPs do not provide WQCV because of site constraints. Refer to
DEVELOPMENT CRITERIA REFERENCE AND CONSTRAINTS FOR a list.
Step 3 - Stabilize drainageways
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Planting within the vegetated swales will stabilize the drainage way and prevent erosion during
storm events exceeding the 2-year recurrence level.
Step 4 - Implement site specific and other source control BMPS
Site specific considerations such as material storage and other site operations are addressed
in the Stormwater Management Plan (SWMP).
DEVELOPMENT CRITERIA REFERENCE AND CONSTRAINTS
Several constraints drove the WQ/LID and detention pond design presented here.
· The outfall from the proposed on-site detention pond is the flowline of West Elizabeth
Street, elevation ±5107.41.
· The developer wants to keep the existing house; this constrains the grading design.
· The closest storm drain system is located more than one-half mile east along Elizabeth
Street.
· The site is generally flat. The existing grades average 0.50% to 1.00%. Locally steeper
grades exist around the structures and existing irrigation lateral.
· The project site is bounded by existing development.
· The existing soils are unsuitable for infiltrating stormwater runoff. The boring logs show
clay underlain by claystone/sandstone and claystone. Considering the expansive
nature of the subgrade soils, the subsurface study recommended that residences be
founded on drilled piers.
In summary, we considered alternative volume based LID strategies with underdrains but feel
they are infeasible because of the subsurface study results and site grading constraints.
HYDROLOGICAL CRITERIA
For urban catchments that are not complex and are generally 160 acres or less in size, it is
acceptable that the design storm runoff be analyzed using the Rational Method. The Rational
Method is often used when only the peak flow rate or total volume of runoff is needed (e.g.,
storm sewer sizing or simple detention basin sizing). The Rational Method was used to
estimate the peak flow at each design point. Routing calculations (i.e., time attenuation) that
aggregate the basins draining to a specific design point are include in the Rational Method
calculations in Appendix B.
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The Rational Method is based on the Rational Formula:
Q = CiA
Where:
Q = the maximum rate of runoff, cfs
C = a runoff coefficient that is the ratio between the runoff volume from an area and the
average rate of rainfall depth over a given duration for that area
i = average intensity of rainfall in inches per hour for a duration equal to the Time of
Concentration (Tc)
A = area, acres
The one-hour rainfall Intensity-Duration-Frequency tables for use with the Rational Method of
runoff analysis are provided in Table RA-7 and Table RA-8 (refer to Appendix B).
The 2-year and 100-year storm events serve as the basis for the drainage system design. The
2-year storm is considered the minor storm event. It has a fifty percent probability of
exceedance during any given year. The 100-year storm is considered the major storm event. It
has a one percent probability of exceedance during any given year.
The 2-year drainage system, at a minimum, must be designed to transport runoff from the 2-
year recurrence interval storm event with minimal disruption to the urban environment. The
100-year drainage system, as a minimum, must be designed to convey runoff from the 100-
year recurrence interval flood to minimize life hazards and health, damage to structures, and
interruption to traffic and services.
HYDRAULIC CRITERIA
Street Capacity Analysis
The street section generally drains from the crown, across the travel lane and into roadside
swales. The proposed street section is bounded by a 9” wide concrete ribbon along each side
of the asphalt.
Storm Drain and Swale Capacity Analysis
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The storm drain system is limited to short culverts and swales that convey runoff underneath
driveways and along the internal streets. The hydraulic analysis will be completed using
Bentley FlowMaster. Refer to Appendix C for general swale calculations.
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V. DRAINAGE FACILITY DESIGN
GENERAL CONCEPT
This preliminary design presents the design of a system for collecting and conveying
developed runoff from the proposed development at Elizabeth Street Farms on-site detention
pond.
The on-site developed runoff in each tributary begins as overland flow from the residential lot
areas (i.e., roof area, concrete hardscape and landscaping). This runoff then flows from the
lots to the swale sections along the backs and fronts of the lots. These swales drain into on-
site detention pond.
SPECIFIC DETAILS
On-Site Detention Pond
The proposed on-site detention pond was sized with the Modified FAA Method. The site
constraints limited the volume of the on-site detention pond to 9479 ft3. The proposed release
rate from the detention pond is 1.2 cfs. This exceeds the calculated 2-year release rate of ±0.6
cfs (combined release from basins EX4 and EX5). There does not appear to be any remaining
areas that can develop in SWMM subbasin 9, except for this site, and the site is located at the
far west end of the basin. Considering this, the proposed increase in release rate will have a
negligible effect on the basin during the 100-year storm event. The pond will discharge to the
flowline in West Elizabeth Street.
A Basins
These basins comprise approximately 1.84 acres. The developed runoff from the roof areas
will flow overland through landscaping and into vegetated swales along the private internal
streets. Flow in the swales will drain into the on-site detention pond.
B Basin
This basin includes private street improvements and portions of two lots. It will drain to Pear
Street undetained. The proposed flows should have a negligible impact on the existing
drainage system in this area.
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OS1 Basin
This basin includes future West Elizabeth Street right-of-way and existing West Elizabeth
Street improvements. The runoff will continue to flow east along Elizabeth Street.
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VI. EROSION AND SEDIMENT CONTROL MEASURES
A General Permit for Stormwater Discharge Associated with Construction Activities issued by
the Colorado Department of Public Health and Environment (CDPHE), Water Quality Control
Division (WQCD), will be acquired for the site. A Stormwater Management Plan (SWMP) will
be prepared and is presented under separate cover. It will identify the Best Management
Practices (BMPs) which, when implemented, will meet the requirements of the General Permit.
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VII. CONCLUSIONS
COMPLIANCE WITH STANDARDS
The design presented in this preliminary drainage report for Elizabeth Street Farms has been
prepared in accordance with the design standards and guidelines presented in the Fort Collins
Stormwater Criteria Manual.
VARIANCES
No variances are being requested with the proposed improvements described herein.
DRAINAGE CONCEPT
The proposed Elizabeth Street Farms storm drainage improvements should provide adequate
protection for the developed site. The proposed drainage design for the site should not
negatively impact the existing downstream storm drainage system.
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VII. REFERENCES
1. Fort Collins Stormwater Criteria Manual (Addendum to the Urban Storm Drainage
Criteria Manuals Volumes 1, 2 and 3), prepared by City of Fort Collins.
2. Urban Drainage and Flood Control District, Drainage Criteria Manual Volumes 1 and 2,
prepared by Wright-McLaughlin Engineers, dated June 2001 (revised April 2008), and
the Volume 3, prepared by Wright-McLaughlin Engineers, dated September 1992 and
revised November 2010.
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APPENDIX A
REFERENCE MATERIAL
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VICINITY MAP
Vicinity Map
Not to Scale
West Elizabeth Street
Rocky Road
Project Site
Overland Trail
Timber Lane
Pearl Street
Orchard Place
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NRCS SOILS MAP
Hydrologic Soil Group—Larimer County Area, Colorado
(2620 West Elizabeth Street)
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
10/25/2016
Page 1 of 4
4491570 4491580 4491590 4491600 4491610 4491620 4491630 4491640 4491650 4491660 4491670
4491570 4491580 4491590 4491600 4491610 4491620 4491630 4491640 4491650 4491660 4491670
489340 489350 489360 489370 489380 489390 489400 489410 489420 489430 489440 489450 489460 489470 489480 489490
489340 489350 489360 489370 489380 489390 489400 489410 489420 489430 489440 489450 489460 489470 489480 489490
40° 34' 32'' N
105° 7' 33'' W
40° 34' 32'' N
105° 7' 26'' W
40° 34' 29'' N
105° 7' 33'' W
40° 34' 29'' N
105° 7' 26'' W
N
Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 13N WGS84
0 35 70 140 210
Feet
0 10 20 40 60
Meters
Map Scale: 1:765 if printed on A landscape (11" x 8.5") sheet.
Warning: Soil Map may not be valid at this scale.
MAP LEGEND MAP INFORMATION
Area of Interest (AOI)
Area of Interest (AOI)
Soils
Soil Rating Polygons
A
A/D
B
B/D
C
C/D
D
Not rated or not available
Soil Rating Lines
A
A/D
B
B/D
C
C/D
D
Not rated or not available
Soil Rating Points
A
A/D
B
B/D
C
C/D
D
Not rated or not available
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: http://websoilsurvey.nrcs.usda.gov
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
Hydrologic Soil Group
Hydrologic Soil Group— Summary by Map Unit — Larimer County Area, Colorado (CO644)
Map unit symbol Map unit name Rating Acres in AOI Percent of AOI
3 Altvan-Satanta loams, 0
to 3 percent slopes
B 0.8 31.6%
4 Altvan-Satanta loams, 3
to 9 percent slopes
B 1.7 68.4%
Totals for Area of Interest 2.6 100.0%
Description
Hydrologic soil groups are based on estimates of runoff potential. Soils are
assigned to one of four groups according to the rate of water infiltration when the
soils are not protected by vegetation, are thoroughly wet, and receive precipitation
from long-duration storms.
The soils in the United States are assigned to four groups (A, B, C, and D) and
three dual classes (A/D, B/D, and C/D). The groups are defined as follows:
Group A. Soils having a high infiltration rate (low runoff potential) when thoroughly
wet. These consist mainly of deep, well drained to excessively drained sands or
gravelly sands. These soils have a high rate of water transmission.
Group B. Soils having a moderate infiltration rate when thoroughly wet. These
consist chiefly of moderately deep or deep, moderately well drained or well drained
soils that have moderately fine texture to moderately coarse texture. These soils
have a moderate rate of water transmission.
Group C. Soils having a slow infiltration rate when thoroughly wet. These consist
chiefly of soils having a layer that impedes the downward movement of water or
soils of moderately fine texture or fine texture. These soils have a slow rate of water
transmission.
Group D. Soils having a very slow infiltration rate (high runoff potential) when
thoroughly wet. These consist chiefly of clays that have a high shrink-swell
potential, soils that have a high water table, soils that have a claypan or clay layer
at or near the surface, and soils that are shallow over nearly impervious material.
These soils have a very slow rate of water transmission.
If a soil is assigned to a dual hydrologic group (A/D, B/D, or C/D), the first letter is
for drained areas and the second is for undrained areas. Only the soils that in their
natural condition are in group D are assigned to dual classes.
Rating Options
Aggregation Method: Dominant Condition
Hydrologic Soil Group—Larimer County Area, Colorado 2620 West Elizabeth Street
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
10/25/2016
Page 3 of 4
Component Percent Cutoff: None Specified
Tie-break Rule: Higher
Hydrologic Soil Group—Larimer County Area, Colorado 2620 West Elizabeth Street
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
10/25/2016
Page 4 of 4
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FEMA FIRMETTE
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CITY OF FORT COLLINS FLOOD
MAPPING
1,128
188.0
2620 West Elizabeth Street
Fort Collins, Colorado
This map is a user generated static output from the City of Fort Collins FCMaps
Internet mapping site and is for reference only. Data layers that appear on this
map may or may not be accurate, current, or otherwise reliable.
City of Fort Collins - GIS
143.0
1:
WGS_1984_Web_Mercator_Auxiliary_Sphere
0 71.50 143.0 Feet
Notes
Legend
857
FEMA Floodplain
FEMA High Risk - Floodway
FEMA High Risk - 100 Year
FEMA Moderate Risk - 100 / 500 Year
FEMA Map Panel
City Floodplains
City High Risk - Floodway
City High Risk - 100 Year
City Moderate Risk - 100 Year
City Limits
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APPENDIX B
HYDROLOGY CALCULATIONS
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EXISTING RUNOFF CALCULATIONS
Subdivision: Elizabeth Street Farms Project Name: 2620 West Elizabeth Street
Location: CO, Fort Collins Project No.:
Calculated By: H. Feissner
Checked By: H. Feissner
INPUT User Input Date: 11/1/16
INPUT User Input Single-Family Alley-Loaded SF Duplex/AttachedMulti-Family
95% 5% 62.5% 70% 75% 80%
EX1 0.05 50 0.00 0 20 0.05 20 95 0.00 0 0.20
EX2 0.10 50 0.00 0 20 0.0998235 20 95 0.00 0 0.20
EX3 0.18 50 0.00 0 20 0.1802596 20 95 0.00 0 0.20
EX4 0.76 50 0.05 3 20 0.6972378 18 95 0.01 1 0.23
EX5 1.26 50 0.00 0 20 1.2228005 19 95 0.04 3 0.22
Σ Basins 2.35
COMPOSITE RUNOFF COEFFICIENTS
Area (ac) Area
Weighted
Gravel (e.g., driveway) Undeveloped, Heavy Soil: Flat <2%
Area Weighted Runoff
Coefficient Area (ac)
HPB01.01
Area
Weighted
C2
Basin ID Total Area (ac) Runoff
Coefficient Area (ac)
Existing Roof and Concrete (e.g., slab)
Runoff
Coefficient
Page 1 of 1 11/1/2016
Subdivision: Elizabeth Street Farms Project Name: 2620 West Elizabeth Street
Location: CO, Fort Collins Project No.:
Calculated By: H. Feissner
Checked By: H. Feissner
Date: 11/1/16
1 2 3 4 5 6 7 8 9 10 13 14 16 17 18 19 20 21 22 23 24
BASIN D.A. Hydrologic C2 C
5 C100
U.S. D.S. L Calculated S Ti | 2-Year T
i | 100-Year L Calculated Cv
VEL. Tt COMP. T
c | 2-Year COMP. Tc | 100-Year
TOTAL Urbanized Tc T
c | 2-Year Tc | 100-Year
ID (AC) Soils Group Cf=1.00 C
f=1.00 Cf
=1.25 (FT) Slope, % (%) (MIN) (MIN) (FT) Slope, % (FPS) (MIN) (MIN) (MIN) LENGTH(FT) (MIN) (MIN) (MIN)
EX1 0.05 C 0.20 0.20 0.25 12.26 10.94 10 13.20 2.00 2.3 2.1 0 0.00 15 0.0 0.0 2.3 2.1 10 10.1 5.0 5.0
EX2 0.10 C 0.20 0.20 0.25 9.14 7.84 50 2.60 2.00 8.7 8.2 0 0.00 15 0.0 0.0 8.7 8.2 50 10.3 8.7 8.2
EX3 0.18 C 0.20 0.20 0.25 12.19 10.83 10 13.60 2.00 2.2 2.1 0 0.00 15 0.0 0.0 2.2 2.1 10 10.1 5.0 5.0
EX4 0.76 C 0.23 0.23 0.29 11.30 7.84 304 1.14 2.00 27.1 25.3 0 0.00 15 0.0 0.0 27.1 25.3 304 11.7 27.1 25.3
EX5 1.26 C 0.22 0.22 0.28 12.56 9.14 342 1.00 2.00 30.4 28.5 0 0.00 15 0.0 0.0 30.4 28.5 342 11.9 30.4 28.5
NOTES:
Ti = (1.87*(1.1 - CC
f)*(L)^0.5)/((S)^0.33), S in % Cv
Tt=L/60V (Velocity From Fig. 501) 2.5
Velocity V=Cv*S^0.5, S in ft/ft 5
Tc Check = 10+L/180 7
For Urbanized basins a minimum Tc of 5.0 minutes is required. 10
For non-urbanized basins a minimum Tc of 10.0 minutes is required 15
20
FG Elevations
Paved Areas and Shallow Paved Swales
DATA
Type of Land Surface
Heavy Meadow
Tillage/Field
Short Pasture and Lawns
Nearly Bare Ground
Grassed Waterway
INITIAL/OVERLAND FINAL
(Ti)
TRAVEL TIME
(Tt) (URBANIZED BASINS)
STANDARD FORM SF-2
TIME OF CONCENTRATION
SUB-BASIN Tc CHECK
HPB01.01
Page 1 of 1 11/1/2016
Project Name: 2620 West Elizabeth Street
Subdivision: Elizabeth Street Farms Project No.: HPB01.01
Location: CO, Fort Collins Calculated By: H. Feissner
Design Storm: Checked By: H. Feissner
Date:
TRAVEL TIME
STREET
Design Point
Basin ID
Area (Ac)
Runoff Coeff. | C 2
Tc | 2-Year (min)
C*A (Ac)
I (in/hr)
Q (cfs)
Tc (min)
C*A (Ac)
I (in/hr)
Q (cfs)
Slope (%)
Street Flow (cfs)
Design Flow (cfs)
Slope (%)
Pipe Size (inches)
Length (ft)
Velocity (fps)
Tt (min)
REMARKS
EX1 EX1 0.05 0.20 5.0 0.01 2.86 0.0
EX2 EX2 0.10 0.20 8.7 0.02 2.39 0.0
EX3 EX3 0.18 0.20 5.0 0.04 2.86 0.1
EX4 EX4 0.76 0.23 27.1 0.18 1.36 0.2
EX5 EX5 1.26 0.22 30.4 0.28 1.27 0.4
DIRECT RUNOFF TOTAL RUNOFF STREET PIPE
STANDARD FORM SF-3
STORM DRAINAGE SYSTEM DESIGN
(RATIONAL METHOD PROCEDURE)
2-Year
11/1/16
Page 1 of 1 11/1/2016
STANDARD FORM SF-3
STORM DRAINAGE SYSTEM DESIGN
(RATIONAL METHOD PROCEDURE)
Project Name: 2620 West Elizabeth Street
Subdivision: Elizabeth Street Farms Project No.: HPB01.01
Location: CO, Fort Collins Calculated By: H. Feissner
Design Storm: Checked By: H. Feissner
Date:
TRAVEL TIME
STREET
Design Point
Basin ID
Area (Ac)
Runoff Coeff. | C 100
Tc | 100-Year (min)
C*A (Ac)
I (in/hr)
Q (cfs)
Tc (min)
C*A (Ac)
I (in/hr)
Q (cfs)
Slope (%)
Street Flow (cfs)
Design Flow (cfs)
Slope (%)
Pipe Size (inches)
Length (ft)
Velocity (fps)
Tt (min)
REMARKS
EX1 EX1 0.05 0.25 5.0 0.01 9.98 0.1
EX2 EX2 0.10 0.25 8.2 0.02 8.52 0.2
EX3 EX3 0.18 0.25 5.0 0.05 9.98 0.4
EX4 EX4 0.76 0.29 25.3 0.22 4.93 1.1
EX5 EX5 1.26 0.28 28.5 0.35 4.59 1.6
100-Year
DIRECT RUNOFF TOTAL RUNOFF STREET
11/1/16
PIPE
Page 1 of 1 11/1/2016
`
PROPOSED RUNOFF
CALCULATIONS
41
Table RO-11
Rational Method Runoff Coefficients for Composite Analysis
Character of Surface Runoff Coefficient
Streets, Parking Lots,
Drives:
Asphalt 0.95
Concrete 0.95
Gravel 0.5
Roofs 0.95
Recycled Asphalt 0.8
Lawns, Sandy Soil:
Flat <2% 0.1
Average 2 to 7% 0.15
Steep >7% 0.2
Lawns, Heavy Soil:
Flat <2% 0.2
Average 2 to 7% 0.25
Steep >7% 0.35
(4) A new Section 2.9 is added, to read as follows:
2.9 Composite Runoff Coefficient
Drainage sub-basins are frequently composed of land that has multiple surfaces or zoning
classifications. In such cases a composite runoff coefficient must be calculated for any
given drainage sub-basin.
The composite runoff coefficient is obtained using the following formula:
( )
t
n
i
i i
A
C A
C
∑
= = 1
*
(RO-8)
Where: C = Composite Runoff Coefficient
Ci = Runoff Coefficient for Specific Area (Ai)
Ai = Area of Surface with Runoff Coefficient of Ci, acres or feet2
n = Number of different surfaces to be considered
At = Total Area over which C is applicable, acres or feet2
(5) A new Section 2.10 is added, to read as follows:
42
2.10 Runoff Coefficient Adjustment for Infrequent Storms
The runoff coefficients provided in tables RO-10 and RO-11 are appropriate for use with
the 2-year storm event. For storms with higher intensities, an adjustment of the runoff
coefficient is required due to the lessening amount of infiltration, depression retention,
evapo-transpiration and other losses that have a proportionally smaller effect on storm
runoff. This adjustment is applied to the composite runoff coefficient.
These frequency adjustment factors are found in Table RO-12.
Table RO-12
Rational Method Runoff Coefficients for Composite Analysis
Storm Return Period
(years)
Frequency Factor
Cf
2 to 10
11 to 25
26 to 50
51 to 100
1.00
1.10
1.20
1.25
Note: The product of C times Cf cannot exceed the value of 1, in the cases where it does a value of
1 must be used
(6) Section 3.1 is deleted in its entirety.
(7) Section 3.2 is deleted in its entirety.
(8) Section 3.3 is deleted in its entirety.
(9) A new Section 4.3 is added, to read as follows:
4.3 Computer Modeling Practices
(a) For circumstances requiring computer modeling, the design storm hydrographs must
be determined using the Stormwater Management Model (SWMM). Basin and
conveyance element parameters must be computed based on the physical characteristics
of the site.
(b) Refer to the SWMM Users’ Manual for appropriate modeling methodology, practices
and development. The Users’ Manual can be found on the Environmental Protection
Agency (EPA) website (http://www.epa.gov/ednnrmrl/models/swmm/index.htm).
(c) It is the responsibility of the design engineer to verify that all of the models used in
the design meet all current City criteria and regulations.
4.3.1 Surface Storage, Resistance Factors, and Infiltration
Table RO-13 provides values for surface storage for pervious and impervious surfaces
and the infiltration rates to be used with SWMM. Table RO-13 also lists the appropriate
infiltration decay rate, zero detention depth and resistance factors, or Manning’s “n”
values, for pervious and impervious surfaces to be used for SWMM modeling in the city
of Fort Collins.
Subdivision: Elizabeth Street Farms Project Name: 2620 West Elizabeth Street
Location: CO, Fort Collins Project No.:
Calculated By: H. Feissner
Checked By: H. Feissner
INPUT User Input Date: 7/11/17
INPUT User Input Single-Family Alley-Loaded SF Duplex/AttachedMulti-Family
95% 5% 60% 70% 75% 80%
A1 0.22 95 0.00 0 20 0.00 0 60 0.22 60 0.60
A2 0.39 95 0.12 29 20 0.03 1 60 0.25 38 0.68
A3 0.61 95 0.18 28 20 0.03 1 60 0.41 40 0.68
A4 0.32 95 0.00 0 20 0.06 4 60 0.26 49 0.53
A5 0.29 95 0.04 12 20 0.25 17 60 0.00 0 0.30
B1 0.28 95 0.08 26 20 0.01 1 60 0.19 41 0.68
OS1 0.44 95 0.35 76 20 0.09 4 60 0.00 0 0.80
Σ Basins 2.56
ΣDetention Pond Tributary Area 1.84
COMPOSITE RUNOFF COEFFICIENTS
Area (ac) Area
Weighted
Asphalt + Concrete Walks Lawns, Heavy Soil: Flat <2%
Area Weighted Runoff
Coefficient Area (ac)
HPB01.01
Area
Weighted
C2
Basin ID Total Area (ac) Runoff
Coefficient Area (ac)
Lots (e.g., Single-Family, Alley Loaded)
Runoff
Coefficient
Page 1 of 1 7/11/2017
Subdivision: Elizabeth Street Farms Project Name: 2620 West Elizabeth Street
Location: CO, Fort Collins Project No.:
Calculated By: H. Feissner
Checked By: H. Feissner
Date: 7/11/17
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
BASIN D.A. Hydrologic C2 C5 C100 L S Ti | 2-Year Ti | 100-Year U.S. D.S. L Calculated S Cv VEL. Tt COMP. Tc | 2-Year COMP. Tc | 100-Year TOTAL Urbanized Tc Tc | 2-Year Tc | 100-Year
ID (AC) Soils Group Cf=1.00 Cf=1.00 Cf=1.25 (FT) (%) (MIN) (MIN) (FT) Slope, % (%) (FPS) (MIN) (MIN) (MIN) LENGTH(FT) (MIN) (MIN) (MIN)
A1 0.22 C 0.60 0.60 0.75 50 2.00 5.2 3.7 9.87 8.90 158 0.61 0.00 15 1.2 2.2 7.5 5.9 208 11.2 7.5 5.9
A2 0.39 C 0.68 0.68 0.85 63 2.00 5.0 3.0 10.09 8.79 195 0.67 0.00 15 1.2 2.7 7.6 5.6 258 11.4 7.6 5.6
A3 0.61 C 0.68 0.68 0.85 102 2.00 6.2 3.7 10.29 9.14 226 0.51 0.00 15 1.1 3.5 9.8 7.2 328 11.8 9.8 7.2
A4 0.32 C 0.53 0.53 0.66 52 2.00 6.1 4.7 11.04 9.54 249 0.60 0.00 15 1.2 3.6 9.7 8.3 301 11.7 9.7 8.3
A5 0.29 C 0.30 0.30 0.37 35 2.00 7.0 6.4 7.90 7.60 59 0.51 0.00 15 1.1 0.9 8.0 7.3 94 10.5 8.0 7.3
B1 0.28 C 0.68 0.68 0.85 130 2.00 7.1 4.2 50.00 50.00 0 0.00 20 0.0 0.0 7.1 4.2 130 10.7 7.1 5.0
OS1 0.44 C 0.80 0.80 1.00 28 2.00 2.4 0.8 11.44 7.53 392 1.00 0.00 20 2.0 3.3 5.6 4.1 420 12.3 5.6 5.0
NOTES:
Ti = (1.87*(1.1 - CCf)*(L)^0.5)/((S)^0.33), S in % Cv
Tt=L/60V (Velocity From Fig. 501) 2.5
Velocity V=Cv*S^0.5, S in ft/ft 5
Tc Check = 10+L/180 7
For Urbanized basins a minimum Tc of 5.0 minutes is required. 10
For non-urbanized basins a minimum Tc of 10.0 minutes is required 15
Paved Areas and Shallow Paved Swales 20
DATA
Type of Land Surface
Heavy Meadow
Tillage/Field
Short Pasture and Lawns
Nearly Bare Ground
Grassed Waterway
INITIAL/OVERLAND FINAL
(Ti)
Hide TRAVEL TIME
FG Elevations (Tt) (URBANIZED BASINS)
STANDARD FORM SF-2
TIME OF CONCENTRATION
SUB-BASIN Tc CHECK
HPB01.01
Page 1 of 1 7/11/2017
36
RAINFALL INTENSITY-DURATION-FREQUENCY CURVE
0.00
1.00
2.00
3.00
4.00
5.00
6.00
7.00
8.00
9.00
10.00
0.00 10.00 20.00 30.00 40.00 50.00 60.00
STORM DURATION (minutes)
RAINFALL INTENSITY (inches/hour)
2-Year Storm 10-Year Storm 100-Year Storm
Figure RA-16 City of Fort Collins Rainfall Intensity-Duration-Frequency Curves
(13) Section 5.0 is deleted in its entirety.
(14) Section 6.0 is deleted in its entirety.
(15) Section 7.0 is deleted in its entirety.
(16) Section 7.1 is deleted in its entirety.
(17) Section 7.2 is deleted in its entirety.
(18) Section 7.3 is deleted in its entirety.
(19) Section 8.0 is deleted in its entirety.
(20) Table RA-1 is deleted in its entirety.
Project Name: 2620 West Elizabeth Street
Subdivision: Elizabeth Street Farms Project No.: HPB01.01
Location: CO, Fort Collins Calculated By: H. Feissner
Design Storm: Checked By: H. Feissner
Date:
TRAVEL TIME
STREET
Design Point
Basin ID
Area (Ac)
Runoff Coeff. | C 2
Tc | 2-Year (min)
C*A (Ac)
I (in/hr)
Q (cfs)
Tc (min)
C*A (Ac)
I (in/hr)
Q (cfs)
Slope (%)
Street Flow (cfs)
Design Flow (cfs)
Slope (%)
Pipe Size (inches)
Length (ft)
Velocity (fps)
Tt (min)
REMARKS
A1 A1 0.22 0.60 7.5 0.13 2.52 0.3 Lot runoff drains to a rear lot vegetated swale
A2 A2 0.39 0.68 7.6 0.27 2.51 0.7 Lot and private street runoff drains to a vegetated swale
A3 A3 0.61 0.68 9.8 0.42 2.28 1.0 Lot and private street runoff drains to a vegetated swale
A4 A4 0.32 0.53 9.7 0.17 2.29 0.4 Lot runoff drains to a rear lot vegetated swale
A5 A5 0.29 0.30 8.0 0.09 2.47 0.2 On-stie detention pond
B1 B1 0.28 0.68 7.1 0.19 2.57 0.5 Runoff drains to Pear Street (existing)
OS1 OS1 0.44 0.80 5.6 0.35 2.77 1.0 Right-of-Way runoff drains to West Elizabeth Street C&G
DIRECT RUNOFF TOTAL RUNOFF STREET PIPE
STANDARD FORM SF-3
STORM DRAINAGE SYSTEM DESIGN
(RATIONAL METHOD PROCEDURE)
2-Year
7/11/17
Page 1 of 1 7/11/2017
STANDARD FORM SF-3
STORM DRAINAGE SYSTEM DESIGN
(RATIONAL METHOD PROCEDURE)
Project Name: 2620 West Elizabeth Street
Subdivision: Elizabeth Street Farms Project No.: HPB01.01
Location: CO, Fort Collins Calculated By: H. Feissner
Design Storm: Checked By: H. Feissner
Date:
TRAVEL TIME
STREET
Design Point
Basin ID
Area (Ac)
Runoff Coeff. | C 100
Tc | 100-Year (min)
C*A (Ac)
I (in/hr)
Q (cfs)
Tc (min)
C*A (Ac)
I (in/hr)
Q (cfs)
Slope (%)
Street Flow (cfs)
Design Flow (cfs)
Slope (%)
Pipe Size (inches)
Length (ft)
Velocity (fps)
Tt (min)
REMARKS
A1 A1 0.22 0.75 5.9 0.17 9.51 1.6 Lot runoff drains to a rear lot vegetated swale
A2 A2 0.39 0.85 5.6 0.34 9.66 3.2 Lot and private street runoff drains to a vegetated swale
A3 A3 0.61 0.85 7.2 0.53 8.92 4.7 Lot and private street runoff drains to a vegetated swale
A4 A4 0.32 0.66 8.3 0.21 8.49 1.8 Lot runoff drains to a rear lot vegetated swale
A5 A5 0.29 0.37 7.3 0.11 8.87 0.9 On-stie detention pond
B1 B1 0.28 0.85 5.0 0.24 9.98 2.4 Runoff drains to Pear Street (existing )
OS1 OS1 0.44 1.00 5.0 0.44 9.98 4.4 Right-of-Way runoff drains to West Elizabeth Street C&G
100-Year
DIRECT RUNOFF TOTAL RUNOFF STREET
7/11/17
PIPE
Page 1 of 1 7/11/2017
`
APPENDIX C
HYDRAULIC CALCULATIONS
`
SWALE CAPACITY CALCULATIONS
Project Description
Friction Method Manning Formula
Solve For Discharge
Input Data
Roughness Coefficient 0.035
Channel Slope 0.005 ft/ft
Normal Depth 1.00 ft
Left Side Slope 4.00 ft/ft (H:V)
Right Side Slope 3.00 ft/ft (H:V)
Normal Depth (ft) Discharge (ft³/s) Velocity (ft/s) Flow Area (ft²) Wetted Perimeter (ft) Top Width (ft)
0.00 0.00 0.00 0.00
0.10 0.01 0.40 0.04 0.73 0.70
0.20 0.09 0.63 0.14 1.46 1.40
0.30 0.26 0.83 0.32 2.19 2.10
0.40 0.56 1.00 0.56 2.91 2.80
0.50 1.02 1.16 0.88 3.64 3.50
0.60 1.65 1.31 1.26 4.37 4.20
0.70 2.49 1.45 1.72 5.10 4.90
0.80 3.55 1.59 2.24 5.83 5.60
0.90 4.87 1.72 2.84 6.56 6.30
1.00 6.45 1.84 3.50 7.29 7.00
Vegetated Swale
11/1/2016 9:49:52 AM
Bentley Systems, Inc. Haestad Methods Solution BentleCyenter FlowMaster V8i (SELECTseries 1) [08.11.01.03]
27 Siemons Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 Page 1 of 1
`
PRELIMINARY DETENTION POND
SIZING
Project Number: HPB01.01 Date: 7/11/2017
Project Location: Fort Collins, Colorado
Calculations By: H. Feissner
Pond Description: Basin A5
User Input Cell: Blue Text
100-year 9590
0.73 0.22
1.84
1.2
minutes seconds in/hr cubic feet cubic feet cubic feet acre-feet
5 300 9.95 4009 360 3649 0.08
10 600 7.72 6222 720 5502 0.13
15 900 6.52 7882 1080 6802 0.16
20 1200 5.60 9026 1440 7586 0.17
25 1500 4.98 10034 1800 8234 0.19
30 1800 4.52 10928 2160 8768 0.20
35 2100 4.08 11509 2520 8989 0.21
40 2400 3.74 12057 2880 9177 0.21
45 2700 3.46 12548 3240 9308 0.21
50 3000 3.23 13016 3600 9416 0.22
55 3300 3.03 13431 3960 9471 0.22
60 3600 2.86 13830 4320 9510 0.22
65 3900 2.71 14196 4680 9516 0.22
70 4200 2.59 14611 5040 9571 0.22
75 4500 2.48 14990 5400 9590 0.22
80 4800 2.38 15345 5760 9585 0.22
85 5100 2.29 15687 6120 9567 0.22
90 5400 2.21 16030 6480 9550 0.22
95 5700 2.13 16308 6840 9468 0.22
100 6000 2.06 16602 7200 9402 0.22
105 6300 2.00 16924 7560 9364 0.21
110 6600 1.94 17198 7920 9278 0.21
115 6900 1.88 17424 8280 9144 0.21
120 7200 1.84 17795 8640 9155 0.21
Storage
Volume
Modified FAA Method- Storage Colume Calculations
Inputs | Tributary Area Output | Detention Volume
Storm
Duration Time
Rainfall
Intensity Inflow Volume
Catchment 'C':
Catchment Drainage Area, ac:
Return Period for Detention Control: Required Storage, cubic feet:
Required Storage, ac-ft:
Release Rate, cfs:
Average
Outflow
Storage
Volume
Project Number: HPB01.01
Project Location: Fort Collins, Colorado Date: 7/11/2017
Calculations By: H. Feissner
Pond Description: Basin A5
User Input Cell: Blue Text
Design Point: A1
Design Storm: WQCV
Required Volume: 0 ft3 5107.60 ft
Design Storm: 10-year
Required Volume: 0 ft3 5107.60 ft
Design Storm: 100-year
Required Volume: 9590 ft3 5109.60 ft
Contour
Elevation
Contour
Area Depth
Incremental
Volume
Cummulative
Volume
Incremental
Volume
Cummulative
Volume
Cummulative
Volume
ft ft2 ft ft3 ft3 ft3 ft3 ac-ft
5107.60 0 0 0 0 0 0 0.000
5107.80 153 0.20 15 15 11 11 0.000
5108.00 1242 0.20 139 155 122 133 0.003
5108.20 2697 0.20 394 549 385 517 0.012
5108.40 4577 0.20 727 1276 719 1236 0.028
5108.60 5734 0.20 1031 2307 1029 2265 0.052
5108.80 6485 0.20 1222 3529 1221 3486 0.080
5109.00 6967 0.20 1345 4874 1345 4831 0.111
5109.20 7465 0.20 1443 6317 1443 6274 0.144
5109.40 7975 0.20 1544 7861 1544 7818 0.179
5109.60 8634 0.20 1661 9522 1661 9479 0.218
Detention Pond Stage-Storage Calculations
Average End Area Method:
Required Volume Water Surface Elevation
Conic Volume Method:
5108
5108
5109
5109
5110
5110
0 1000 2000 3000 4000 5000 6000 7000 8000 9000
Contour Elevation, ft
Cummulative Volume, ft3
Stage - Storage | Site
`
APPENDIX D
DRAINAGE MAPS
PEAR STREET
WEST ELIZABETHSTREET
DRIVEWAY
PEAR STREET
WEST ELIZABETHSTREET
12''IRR
12''IRR
12''IRR 12''IRR
W
ATER
WELL
EX2
VALLEY HI
SUBDIVISION
BLOCK 4
WEST PLUM STREET-
A PLANNED UNIT
RHODES DEVELOPMENT
SUBDIVISION
WEST PLUM STREET-
A PLANNED UNIT
DEVELOPMENT
EX4
EX5
EX3
EX2
EX1
EX1
EX3
EX4
EX5
EXISTING IRRIGATION
LATERAL
EXISTING IRRIGATION
STRUCTURE
EXISTING IRRIGATION
STRUCTURE
EXISTING HOUSE
#
3760 E. 15th Street, Suite 202
Loveland, CO 80538
970.800.3300 O
www.gallowayUS.com
2016. Galloway & Company, Inc. All Rights Reserved
Date:
Drawn By:
Project No:
Checked By:
THESE PLANS ARE AN INSTRUMENT OF
SERVICE AND ARE THE PROPERTY OF
GALLOWAY, AND MAY NOT BE DUPLICATED,
DISCLOSED, OR REPRODUCED WITHOUT
THE WRITTEN CONSENT OF GALLOWAY.
COPYRIGHTS AND INFRINGEMENTS WILL
BE ENFORCED AND PROSECUTED.
COPYRIGHT
H:\High Plains Builders\CO, Fort Collins - HPB000001.01 - Elizabeth & Pear\CADD\Exhibit\HPB1.01_Exist-DR.dwg LAYOUT NAME: EXIST DATE: Jul 12, 2017 - 10:18am CAD OPERATOR: herman_feissner
LIST OF XREFS: [x-HPB1.01_EMap] [x-HPB1.01_ESite] [x-HPB1.01_ETopo] [x-HPB1.01_EUtil] [x-HPB1.01_Legend_DR-Exist]
NOT FOR CONSTRUCTION
07.12.2017
12''IRR
6''W 6''W
12''IRR 12''IRR
PEAR STREET
WEST ELIZABETH STREET
VALLEY HI
SUBDIVISION
BLOCK 4
WEST PLUM STREET-
A PLANNED UNIT
RHODES DEVELOPMENT
SUBDIVISION
WEST PLUM STREET-
A PLANNED UNIT
DEVELOPMENT
PEAR STREET
BARTLETT DRIVE
VEGETATED SWALE
VEGETATED SWALE
VEGETATED SWALE
QOFFSITE
:
Q2= 0.4 cfs
Q100= 1.7 cfs
PROPOSED HEADWALL
W/ORIFICE PLATE
QRELEASE: 1.2 cfs
PROPOSED CULVERT
PROPOSED CULVERT
PROPOSED
SIDEWALK CHASE
EXISTING HOUSE
(TO REMAIN)
PROPOSED
DETENTION POND
A1
A2
A5
A3
A4
A1
A3
A5
A4
B1
A2
OS1
VEGETATED SWALE
PROPOSED
EMERGENCY SPILLWAY
CREST ELEVATION: 5109.60
PROPOSED
DETENTION POND
#
3760 E. 15th Street, Suite 202
Loveland, CO 80538
970.800.3300 O
www.gallowayUS.com
2016. Galloway & Company, Inc. All Rights Reserved
Date:
Drawn By:
Project No:
Checked By:
THESE PLANS ARE AN INSTRUMENT OF
SERVICE AND ARE THE PROPERTY OF
GALLOWAY, AND MAY NOT BE DUPLICATED,
DISCLOSED, OR REPRODUCED WITHOUT
THE WRITTEN CONSENT OF GALLOWAY.
COPYRIGHTS AND INFRINGEMENTS WILL
BE ENFORCED AND PROSECUTED.
COPYRIGHT
H:\High Plains Builders\CO, Fort Collins - HPB000001.01 - Elizabeth & Pear\CADD\3-CD\HPB1.01_C9.0-DR.dwg LAYOUT NAME: C9.0 DATE: Jul 11, 2017 - 3:55pm CAD OPERATOR: herman_feissner
LIST OF XREFS: [x_HPB1.01_TB] [x-HPB1.01_PGrad] [x-HPB1.01_EMap] [x-HPB1.01_ESite] [x-HPB1.01_ETopo] [x-HPB1.01_EUtil] [x-HPB1.01_PBase] [x-HPB1.01_Legend_DR] [x-HPB1.01_PGrad-FHA]
NOT FOR CONSTRUCTION
07.12.2017
HIGH PLAINS BUILDERS, LLC
P.O. Box 2796
Gillette, WY 82717
307.257.2352
( IN FEET )
1 inch = ft.
30 0 30
30
60 90
CALL 2 BUSINESS DAYS IN ADVANCE BEFORE YOU
DIG, GRADE, OR EXCAVATE FOR THE MARKING OF
UNDERGROUND MEMBER UTILITIES.
CALL UTILITY NOTIFICATION CENTER OF
COLORADO
R
CityDate Engineer
Date
Date
Date
Date
Stormwater Utility
Parks & Recreation
Traffic Engineer
Date
APPROVED:
CHECKED BY:
CHECKED BY:
CHECKED BY:
CHECKED BY:
CHECKED BY:
Water & Wastewater Utility
City of Fort Collins, Colorado
UTILITY PLAN APPROVAL
Environmental Planner
1. VEGETATED SWALE
DETENTION POND WATER SURFACE ELEVATION: 5109.6
NOTES:
1
2 100-YEAR
DESIGN POINT
MAJOR BASIN BOUNDARY
SUB-BASIN BOUNDARY
OVERLAND FLOW DIRECTION
(I.E., LANDSCAPING)
B1
DRAINAGE SYMBOLS:
LEGEND:
DIRECT FLOW DIRECTION
(I.E., PAVEMENT, CURB AND
GUTTER, SWALE)
PROPOSED MAJOR CONTOUR
PROPOSED MINOR CONTOUR
EXISTING MAJOR CONTOUR
EXISTING MINOR CONTOUR
EXISTING STORM SEWER
PROPOSED STORM SEWER
PROPOSED STORM INLET
PROPOSED RIGHT-OF-WAY
FUTURE RIGHT-OF-WAY
PROPOSED LOTLINE
FUTURE LOTLINE
EASEMENT LINE
09
5009
5110
5110
DRAINAGE SUMMARY TABLE | DEVELOPED CONDITION
Tributary Area
C2 C
100
tc | 2-Year tc | 100-Year Q
2 Q100
Sub-basin (acres) (min) (min) (cfs) (cfs)
A1 0.22 0.60 0.75 7.5 5.9 0.3 1.6
A2 0.39 0.68 0.85 7.6 5.6 0.7 3.2
A3 0.61 0.68 0.85 9.8 7.2 1.0 4.7
A4 0.32 0.53 0.66 9.7 8.3 0.4 1.8
A5 0.29 0.30 0.37 8.0 7.3 0.2 0.9
B1 0.28 0.68 0.85 7.1 5.0 0.5 2.4
OS1 0.44 0.80 1.00 5.6 5.0 1.0 4.4
Detention Pond WQCV
100-Year
Volume
ac-ft
100-Year
WSEL
100-Year Release
Rate
cfs
A5 N/A 0.22 5109.6 1.2
DETENTION POND SUMMARY TABLE
HIGH PLAINS BUILDERS, LLC
P.O. Box 2796
Gillette, WY 82717
307.257.2352
( IN FEET )
1 inch = ft.
30 0 30
30
60 90
Tributary Area
C2 C
100
tc | 2-Year tc | 100-Year Q
2 Q100
Sub-basin (acres) (min) (min) (cfs) (cfs)
EX1 0.05 0.20 0.25 5.0 5.0 0.03 0.11
EX2 0.10 0.20 0.25 8.7 8.2 0.05 0.21
EX3 0.18 0.20 0.25 5.0 5.0 0.10 0.45
EX4 0.76 0.23 0.29 27.1 25.3 0.24 1.08
EX5 1.26 0.22 0.28 30.4 28.5 0.35 1.60
DRAINAGE SUMMARY TABLE | EXISTING CONDITION
4550
DESIGN POINT
MAJOR BASIN BOUNDARY
SUB-BASIN BOUNDARY
OVERLAND FLOW DIRECTION
(I.E., LANDSCAPING)
EX1
DRAINAGE SYMBOLS:
LEGEND:
DIRECT FLOW DIRECTION
(I.E., PAVEMENT, CURB AND
GUTTER, SWALE)
4552
EXISTING MAJOR CONTOUR
EXISTING MINOR CONTOUR
EXISTING STORM SEWER
EASEMENT LINE
Survey Area Data: Version 10, Sep 22, 2015
Soil map units are labeled (as space allows) for map scales 1:50,000
or larger.
Date(s) aerial images were photographed: Apr 22, 2011—Apr 28,
2011
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.
Hydrologic Soil Group—Larimer County Area, Colorado
(2620 West Elizabeth Street)
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
10/25/2016
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