HomeMy WebLinkAboutWINDSONG AT ROCK CREEK - FDP - FDP160010 - SUBMITTAL DOCUMENTS - ROUND 1 - DRAINAGE REPORTFINAL DRAINAGE REPORT
FOR
WINDSONG AT ROCK CREEK
Prepared For:
VISTA POINTE DEVELOPMENT CO., LLC
C/O Lenity Architecture
3150 Kettle Court SE
Salem, Oregon 97301
March 1, 2016
Project No. 39727.00
Prepared By:
JR Engineering, LLC
2900 South College Avenue, Suite 3D
Fort Collins, CO 80525
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TABLE OF CONTENTS
Engineer’s Certification Block ........................................................................................................... iii
VICINITY MAP ................................................................................................................................... iv
GENERAL DESCRIPTION AND LOCATION ............................................................................................ 1
LOCATION ..................................................................................................................................... 1
DESCRIPTION OF PROPERTY .......................................................................................................... 1
FLOODPLAIN SUBMITTAL REQUIREMENTS ..................................................................................... 2
DRAINAGE BASINS AND SUB-BASINS ................................................................................................. 3
MAJOR BASINS AND SUB-BASINS ................................................................................................... 3
SUB-BASIN DESCRIPTION ............................................................................................................... 4
EXISTING OFFSITE DRAINAGE BASINS ............................................................................................ 4
EXISTING ONSITE DRAINAGE BASINS ............................................................................................. 5
PROPOSED SUB-BASINS DESCRIPTIONS ......................................................................................... 6
DRAINAGE DESIGN CRITERIA ........................................................................................................... 16
REGULATIONS ............................................................................................................................. 16
MINIMIZATION OF THE DCIA ....................................................................................................... 16
DEVELOPMENT CRITERIA REFERENCE AND CONSTRAINTS ........................................................... 16
HYDROLOGIC CRITERIA ................................................................................................................ 16
HYDRAULIC CRITERIA ................................................................................................................... 17
FLOODPLAIN REGULATIONS COMPLIANCE ................................................................................... 17
MODIFICATIONS OF CRITERA ....................................................................................................... 17
DRAINAGE FACILITY DESIGN ............................................................................................................ 18
GENERAL CONCEPT ..................................................................................................................... 18
WATER QUALITY/ DETENTION FACILITIES .................................................................................... 18
LOW IMPACT DEVELOPMENT ...................................................................................................... 19
CONCLUSIONS ................................................................................................................................. 21
COMPLIANCE WITH STANDARDS ................................................................................................. 21
DRAINAGE CONCEPT ................................................................................................................... 21
REFERENCES .................................................................................................................................... 22
APPENDIX
Appendix A – Figures
Appendix B – Hydrologic Calculations
Appendix C – Hydraulic Calculations
Appendix D – Water Quality/Detention Calculations
Appendix E – Maps
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Engineer’s Certification Block
I hereby certify that this Final Drainage Report for Windsong at Rock Creek was prepared by me (or
under my direct supervision) for JR Engineering, LLC and the owners thereof and meets or exceeds the
criteria of the City of Fort Collins Stormwater Design Standards.
Timothy J. Halopoff, PE
Registered Professional Engineer
State of Colorado No. 37953
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VICINITY MAP
Windsong at Rock Creek
Final Drainage Report
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GENERAL DESCRIPTION AND LOCATION
LOCATION
Windsong at Rock Creek is located in the southeast quarter of Section 4, Township 6 North, Range 68
West of the 6th Principal Meridian in the City of Fort Collins, Larimer County, Colorado. More
specifically, the Windsong site is a 3.334 acre property that is currently undeveloped and is being used
for agricultural purposes. The site is zoned HC, Harmony Corridor, and will support a memory care
facility and associated amenities once developed.
The Windsong at Rock Creek site is bounded on the south by Rock Creek Drive, on the west by
Ziegler Road, and on the north and east by unplatted land. Further to the east of the site lies
Technology Parkway, and further to the north of the site lies existing right-of-way for Precision Drive,
although the roadway has not been constructed between Technology Parkway and Ziegler Road.
Surrounding developments include Harvest Park west of Ziegler Road, Fossil Ridge High School south of
Rock Creek Drive, Harmony Technology Park Filing 3 east of Technology Parkway and
Brookfield/Morningside to the east of Filing 3, and Harmony Technology Park Filing 1 north of Precision
Drive.
The site is only encumbered by a 15-foot utility easement on the west side, paralleling Ziegler Road.
The site is located in the McClellands drainage basin and there are no major drainageways adjacent to
the site.
DESCRIPTION OF PROPERTY
The Windsong at Rock Creek site is 3.334 acres at the northeast corner of Ziegler Road and Rock
Creek Drive. The existing site generally slopes from the southwest to the northeast with slopes ranging
between 0.70% and 3.5%. The property is generally covered with sparse native grasses. The site
currently drains to the east. Runoff sheet flows off the east side of the property and a portion of the
runoff flows to the west after the berm along the far west of the property.
The Windsong site’s soils consist of loamy soil, predominately Nunn clay loam. Nunn clay loam belongs
to hydrologic soils Group C. Group C soils have 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
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moderately fine texture or fine texture. These soils have a slow rate of water transmission. The slopes
of the Nunn clay loam ranges from 0-3 percent. Supporting figures can be found in the Appendix, page
A-1.
An existing irrigation ditch is located on the west end of the site paralleling Ziegler Road. According to
the Main Street Health & Wellness Suites final plat by Edmonds Land Surveying, Inc., recorded May 22,
2015, this irrigation easement has been granted to the Poudre School District. This private irrigation
ditch, per the approved Main Street Health & Wellness Suites Final Drainage and Erosion Control
Report by Aspen Engineering, dated February 18, 2015, is being abandoned in place through the entire
Harmony Technology Park. As such, the irrigation ditch will be abandoned in place with the proposed
Windsong at Rock Creek Development.
The proposed use of the site is a memory care assisted living facility. The proposed concept includes
one main building with two patios, two internal courtyards, garden plaza with walkways, and parking lots
within the perimeter of the site. The proposed main building is 38,131 total square feet.
FLOODPLAIN SUBMITTAL REQUIREMENTS
The site is shown on FEMA FIRM panel 08069C0994F, dated December 19, 2006. The site lies within
Zone X, areas which are determined to be outside the 0.2% annual chance floodplain. The “City of Fort
Collins Floodplain Review Checklist for 50% Submittals” checklist is not applicable for this PDP Drainage
Report. The FIRM panel is included in Appendix A.
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DRAINAGE BASINS AND SUB-BASINS
MAJOR BASINS AND SUB-BASINS
The proposed Windsong Fort Collins site is located in the McClellands major basin. The McClellands
Basin encompasses approximately 3.4 square miles in southeast Fort Collins. The storm runoff from the
basin originates northeast of College Avenue and Harmony Road and drains southeast through the
Oakridge, Willow Springs, Stetson Creek and Harvest Park developments. A single major drainageway,
McClellands Creek, conveys flow from the upper end of the basin to the downstream discharge point
along the Fossil Creek Reservoir Inlet Ditch. The majority of the basin is either developed, or is being
developed, with residential and commercial land areas. There are no major drainageways located within
or immediately adjacent to the site.
The McClellands Basin was developed in accordance with its original master plan and storm drainage
criteria; therefore, many of the recommended improvements were completed. However, there are still
some localized flooding problems. The recommended plan of improvements includes pond enlargement,
spillway construction, and inlet additions. Once these improvements are completed, the existing facilities
would be up to current drainage standards. The “McClellands Creek Basin Selected Plan – Water
Quality Improvements Drainage Master Plan Update”, prepared by ICON Engineering, Inc., shows the
proposed water quality improvements which includes retrofitting the existing Miramont, Oak Ridge,
Willow Springs, Preston Jr. High, and the Harmony Crossing Ponds to accommodate the required water
quality volumes. As well, stream restoration and habitat improvements are proposed along the
McClellands Creek. The Drainage Master Plan update is currently underway and is to portray these
proposed improvements to the McClellands Basin.
The site is located at the east part of the basin outside the McClelland’s Creek Floodplain shown in the
“McClelland’s Creek Master Drainage Plan Update” by Icon Engineering. The site is located south of an
area with existing flood control and east of an area with both existing water quality and flood control.
The site itself is located in an area with neither flood control or water quality. Improvements identified
in the previous approved Drainage Reports include the design of five detention ponds within the
Oak/Cottonwood Farm development prepared by RBD, Inc. Engineering Consultants in May 1992 and
revised in March 1995 [2]. The construction of Lot 1, Lot 2, Boardwalk Crossing, Filing 2 located north
of West Harmony Road and west of South College Avenue has been designed to have the runoff be
routed to the system in Boardwalk Drive and was designed in 1996 by Stewart & Associated, Inc. [3].
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Regional Detention Pond 278 and 247 located west of Pleasant Valley Lake and east of Seneca Street
were designed by Sear-Brown Group in October 2000 [4]. Six detention ponds were designed for the
development north of Ketcher road and west of Strauss Cabin Road by Northern Engineering in
December 2010 [5].
SUB-BASIN DESCRIPTION
Windsong is governed by the City’s Reasonable Use policy, in which the proposed drainage basins will
need to follow the generally accepted principle of releasing the 100-year developed condition flow rate
at the same location and magnitude as the 2-year pre-development condition flow rate. There are offsite
areas that flow across the proposed development site. The existing drainage basins within the site flow
to the either East of the site or North of the site. Referring to the “Existing Drainage Plan”, included in
the Appendix, the following describes the existing condition drainage basins.
EXISTING OFFSITE DRAINAGE BASINS
The site has one existing offsite drainage sub-basin that flow onto the site. The existing offsite land use
is classified as farming/agricultural, but for the analysis, the land use will be assumed to have a 45%
imperviousness (for undefined land use) to be provide a conservative approximation of the offsite flows
entering the Windsong site. The conservative imperviousness will account for any changes or
fluctuations of the surface characteristics north of the site. In the ultimate condition, the offsite flows
will be collected and conveyed to a separate storm system within the respective developments and
these developed flows will no longer enter the Windsong site.
SUB-BASIN (OF1)
Sub-basin OF1 consists of 2.30 acres north of the site and is assumed to drain in a southeasterly
direction onto the subject property. Based on the surveyed surface characteristics north of the
site and the Google topography, the slopes are assumed to match the surveyed area north of
site and will continue to drain in the southeast direction. In the existing condition, runoff from
this portion of the farm field (assumed 2% impervious) is conveyed through the Windsong site.
In the future, the land north of the site is planned to be developed and the offsite runoff will be
directed away from the Windsong property. It is assumed that the slopes are consistent with
the slopes just north of the site, with a range from 0.5% to 1.0%.
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EXISTING ONSITE DRAINAGE BASINS
The site has three existing onsite drainage basins approximately delineated by a high point at the middle
and southern end of the site with sub-basin EX1 on the north half and EX2 on the southern half. Sub-
basin EX2 and sub-basin EX3 border the roadway. Sub-basin EX2 drains to the south and then east
along the curb. Sub-basin EX3 runoff drains to the west and then north along the curb.
SUB-BASIN (EX1)
Sub-basin EX1 consists of a 2.99 acre area of undeveloped farm land with native grasses covering
the majority of the ground and is assumed to be 2% impervious for historic flow analysis. Runoff
from the north farm land (Sub-basins OF1 and OF2) enters the site along the northern
boundary and joins on-site flows. Runoff generally flows southeasterly across basin EX-1, at
slopes ranging from 0.50% to 1.0%. There is an existing low point east of the site that causes
the onsite and offsite runoffs to converge in northern half of the basin and then drain east off
the site. The offsite runoff flows southeast, converges in the northern half, and then flows east
off the site. The sub-basin onsite runoff from the south flows northeast towards the same low
point outside the site.
Towards the southern end of the sub-basin, there is a ridge that directs runoff on the southern
end of the ridge to drain south towards the roadway. An existing berm along the northern
section of the roadway redirects a portion of the runoff back east off the site.
All flows within the sub-basin EX1 exit the site at the east boundary.
SUB-BASIN (EX2)
Sub-basin EX2 consists of a 0.17 acre area of undeveloped farm land with native grasses covering
the majority of the ground and is assumed to be 2% impervious for historic flow analysis. Sub-
basin EX2 borders the north side of the existing Rock Creek Drive roadway. Runoff that that
drains south of the ridge on the southern side of the site flows over the existing berm and into
the roadway curb. The curb then directs the flows to the east. Runoff north of the berm
generally flows southeasterly towards the roadway, at slopes ranging from 0.50% to 0.8%.
Across the berm the slopes range from 6.0%-10.0% and along the curb the slope is ranges from
0.40% to 1.30%.
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SUB-BASIN (EX3)
Sub-basin EX7 consists of a 0.19 acre area of undeveloped farm land with native grasses covering
the majority of the ground and is assumed to be 2% impervious for historic flow analysis. Sub-
basin EX7 borders the east side of the existing Ziegler Road roadway and west of the existing
concrete channel. The runoff drains west of the existing concrete channel and east of the
roadway curb. The stormwater converges to the bottom of the slope that lies in between the
curb and channel before being routed north of the site. The slope ranges from 0.05% to 7.0%.
Along the southwest side of the site and within the sub-basin, the runoff flows west towards the
existing Zeigler Drive roadway and then the curb directs the flows east. The slopes range from
2.5% to 3.0%. All flows within the sub-basin EX2 exit the site at the south end and flow east
along the existing roadway curb.
PROPOSED SUB-BASINS DESCRIPTIONS
No offsite flows will enter the site once it is developed, as concurrent development is expected to take
place for the filing north of the Windsong site. Offsite flows will be accounted for with onsite water
quality and detention in their respective filings.
SUB-BASIN A1
Sub-basin A1consists of 0.39 acres and is located at the northwest corner of the subject
property. Sheet flow from the northwest side of the proposed building and parking lot will
travel north to a parking lot curb. A perforated underdrain pipe will be placed approximately
one foot from the curb flow line and is to collect the runoff from the building and parking lot.
Once the runoff drains into the perforated pipe, it will route the runoff to the stormwater
system on the east side of the site. In situations in which the perforated pipe is at full capacity,
the flows will bypass the underdrain and will be routed to a concrete drain pad which will be set
at the low point in the curb. The runoff will outfall at the concrete pad and into the bio-swale
to the north which will then travel east to the FES. The flow will be piped and then routed east
and then south through the storm sewer to outfall into Detention Pond A. The east side of the
berm along the northwest corner of the site will direct the sheet flows to collect on the parking
lot and sheet flow towards the low point in the curb.
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The slope of the initial flow across the parking lot is ranges from 2.0 % to 2.10% and across the
pavers the slope is 0.75%. The longitudinal slope of the sidewalks ranges from 0.5% to 4.5%.
The imperviousness of the asphalt and pavers is set at 100% and the imperviousness of the
concrete curb and sidewalks/walkways is set at 90%. The imperviousness of the roof of the
building will be set at 90%. All areas outside the parking lot, building and sidewalks are assumed
to be lawn with an imperviousness set at 5%.
SUB-BASIN A2
Sub-basin A2 consists of 0.50 acres and is located at the northeast corner of the subject
property, adjacent to sub-basin A1. Sheet flow from the north-center and northeast side of the
proposed building and parking lot travels north to a parking lot curb. A perforated underdrain
pipe will be placed approximately one foot from the curb flow line for the full stretch of the
curb and is to collect the initial sheet flow from the building and parking lot. Once the runoff
drains into the perforated pipe, the stormwater will be routed to the stormwater system on the
east side of the site. In situations in which the perforated pipe is at full capacity, the flows will
bypass the underdrain and will be routed to a concrete drain pad which will be set at the low
point in the east corner of the curb. There will be two concrete pads along the curb, one to
the west of the trash enclosure and the second at the midpoint of the curb on the east side of
the trash enclosure. The runoff will outfall at the concrete pads and into the second bio-swale
to the north. The bio-swale beings at the first concrete drain pad and directs the flows east
through the swale and outfalls to the proposed grated manhole at the north east corner. The
flow will be piped through the storm sewer system to outfall into Detention Pond A. The west
side of the berm along the northeast corner of the site will direct the sheet flows to collect on
the parking lot or swale.
The slope of the initial flow across the parking lot is ranges from 1.90 % to 3.0% and across the
pavers the slope is 0.75%. The longitudinal slope of the sidewalks ranges from 0.5% to 7.5%.
The imperviousness of the asphalt and pavers is set at 100% and the imperviousness of the
concrete curb and sidewalks/walkways is set at 90%. The imperviousness of the roof of the
building will be set at 90%. All areas outside the parking lot, building and sidewalks are assumed
to be lawn with an imperviousness set at 5%.
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SUB-BASIN A3
Sub-basin A3 consists of 0.08 acres and is located on the east side of the subject property.
Runoff from this basin drains to the proposed sump inlet at DP3. Captured flows are piped to
the sand filter in basin A8 before being routed south to Detention Pond A before exiting the
site. The slope towards the sump inlet ranges from 5.0 % to 25.0%. All areas outside the
parking lot, building and sidewalks are assumed to be lawn with an imperviousness set at 5%.
SUB-BASIN A4
Sub-basin A4 consists of 0.18 acres and is located on the west side of the building within the
subject property. The basin consists of the building patio and the swale directing flow to the
north. Runoff from the west side of the building will flow from the roof and into the concrete
patio or grated manhole north of the patio. In the patio area, the runoff will enter the four
proposed grated manholes with the piped flows routed east. The swale west of the patio berm
collects the runoff from the berms on the east and west side of the swale and directs the flows
north to the proposed grated manhole outside of the patio. The piped flows will then travel
south and combine with the piped flows from within the patio. The piped flows travel west and
connect to the proposed storm sewer system on the west side of the building patio with a tee
fitting. The storm sewer system directs the runoff south to Detention Pond B before exiting
the site.
The slope of the initial flow across the concrete courtyard lot ranges from 1.00 % to 2.0%. The
imperviousness of the concrete is set at 90%. The imperviousness of the roof of the building
will be set at 90%. All areas outside the parking lot, building and sidewalks are assumed to be
lawn with an imperviousness set at 5%.
SUB-BASIN A5
Sub-basin A5 consists of 0.24 acres and encompasses the west-half of the building within the
subject property. Runoff from the west half of the building will flow from the roof and into the
concrete courtyard. The runoff will enter two proposed grated manholes with the piped flows
routed west. The runoff in sub-basin A5 combines with the piped flows from sub-basin A4. The
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piped flows travel west and connect to the proposed storm sewer system on the west side of
the building patio with a tee fitting. The storm sewer system directs the runoff south to
Detention Pond B before exiting the site.
The slope of the initial flow across the concrete courtyard lot ranges from 1.00 % to 2.0%. The
imperviousness of the concrete is set at 90%. The imperviousness of the roof of the building
will be set at 90%.
SUB-BASIN A6
Sub-basin A6 consists of 0.24 acres and encompasses the east-half of the building within the
subject property. Runoff from the east half of the building will flow from the roof and into the
concrete courtyard. The runoff will enter two proposed grated manholes with the piped flows
routed east. The piped flows travel east and connect to the proposed storm sewer system on
the east side of the building patio (sub-basin A8) with a tee fitting. The storm sewer system
directs the runoff south to Detention Pond A before exiting the site.
The slope of the initial flow across the concrete courtyard lot ranges from 1.00 % to 2.0%. The
imperviousness of the concrete is set at 90%. The imperviousness of the roof of the building
will be set at 90%.
SUB-BASIN A7
Sub-basin A7 consists of 0.10 acres and is located on the east side of the building within the
subject property. The basin consists of only the building patio. Runoff from the east side of the
building will flow from the roof into the concrete patio and enter the four proposed grated
manholes with the piped flows routed east. The runoff in sub-basin A7 combines with the piped
flows from sub-basin A6. The piped flows travel east and connect to the proposed storm sewer
system on the east side of the building patio (sub-basin A8) with a tee fitting. The storm sewer
system directs the runoff south to Detention Pond A before exiting the site.
The slope of the initial flow across the concrete courtyard lot ranges from 1.00 % to 2.0%. The
imperviousness of the concrete is set at 90%. The imperviousness of the roof of the building
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will be set at 90%. All areas outside the parking lot, building and sidewalks are assumed to be
lawn with an imperviousness set at 5%.
SUB-BASIN A8
Sub-basin A8 consists of 0.19 acres and is located on the east side of the building and patio
within the subject property. Runoff from the southeast side of the building patio berm will be
routed to the proposed grated manhole at the southeast corner of the building. The ridge along
the east side of the sub-basin is set higher than the sidewalk, directing the runoff on the east
side of the ridge to flow to the private roadway. The runoff within the sub-basin outfall into the
grated manhole and the piped flows travel south to Detention Pond A prior to exiting the site.
The slope of the initial flow across the lawns range from 2.0 % to 25% and across the patio the
slope is ranges from 1.0% to 2.0%. The imperviousness of the concrete patio is set at 90% and
the imperviousness of the roof of the building will also be set at 90%. All areas outside the
building and patio are assumed to be lawn with an imperviousness set at 5%.
SUB-BASIN A9
Sub-basin A9 consists of 0.09 acres and is located on the south side of the building within the
subject property. The sub-basin includes a proposed grated manhole and swale. Runoff from
the building sheet falls into the swale and is routed west towards the proposed grated manhole.
The piped flows are routed south through the sub-basin A10 proposed grated manhole and A11
inlet prior to outfalling into Detention Pond A. The slope towards the grated manhole ranges
from 8.0 % to 20.0% with the swale slope at a 2.0%. All areas outside the parking lot, building
and sidewalks are assumed to be lawn with an imperviousness set at 5%.
SUB-BASIN A10
Sub-basin A10 consists of 0.02 acres and is located in the middle of the south parking lot within
the subject property. Runoff from the sidewalk to the west of the basin sheet falls to the
proposed grated manhole at the center of the sub-basin. The piped flows are routed east
through the sub-basin A11 proposed inlet prior to outfalling into Detention Pond A. The sub-
basin runoff is combined with sub-basin A10 piped flows. The slope towards the grated
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manhole ranges from 2.0 % to 15.0%. The imperviousness of the concrete patio is set at 90%
and all areas outside the parking lot, building and sidewalks are assumed to be lawn with an
imperviousness set at 5%.
SUB-BASIN A11
Sub-basin A11consists of 0.12 acres and is located north of the south property entrance of the
subject property. A ridge will stretch from the west side of the property entrance and north to
the sub-basin B5 curb, causing the parking lot to be broken up into two sub-basins. The two
sub-basins will be located on the east and west side of the parking lot, with sub-basin A11 on
the east side. The runoff from the property entrance travels northeast and the runoff on the
east side of the building entrance travels southeast to the inlet prior to outfalling into
Detention Pond A. The piped flows at the inlet will combine with runoff from sub-basins B1 to
B5 and A9 to A10.
The slope of the initial flow across the parking lot is ranges from 0.05 % to 2.8% and the slope
across the sidewalks/pathways ranges from 1.0% to 4.0%. The imperviousness of the asphalt is
set at 100% and the imperviousness of the concrete curb and sidewalks/walkways is set at 90%.
The imperviousness of the roof of the building will be set at 90%.
SUB-BASIN A12
Sub-basin A12 consists of 0.29 acres and is located at the southeast corner of the property and
consists of the Detention Pond A. The pond will collect runoff from sub-basins A1 to A11 and
B1 to B5 prior to exiting the site. In a major storm situation, the stormwater in the pond can
back up into WQ Pond B, which is tributary to Detention Pond A. The sub-basin itself includes
the pond and the parking lot to the north of the pond. A proposed concrete pad will be placed
at the low point in the curb, causing the runoff in the parking lot to sheet flow and drain into the
pond. At the east side of the pond, a water quality outlet structure with a restrictor plate is
proposed to outfall the stormwater to the existing storm sewer system to the east of the site.
The slope of the sheet flow across the parking lot ranges from 0.75 % to 2.0% and the slope
across the bottom of the pond is approximately 2.0%. The imperviousness of the asphalt is set
at 100% and the imperviousness of the concrete curb and sidewalks/walkways is set at 90%.
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The imperviousness of the roof of the building will be set at 90% and all areas outside the
parking lot, building and sidewalks are assumed to be lawn with an imperviousness set at 5%.
SUB-BASIN B1
Sub-basin B1 consists of 0.04 acres and is located at the southwest side of the building patio
within the subject property. The sub-basin consists of a proposed grated manhole and swale.
Runoff from the berm along the patio and the berm on the east side of the sidewalk, collects
into the swale and is routed to the proposed grated manhole. The manhole also collects the
runoff from building and the second berm east of the sidewalk. The piped flows outfall into
Detention Pond B where the runoff is then routed to the Detention Pond A. The slope of the
swale is approximately 2.0% and the slope from the building and berms ranges from 10.0 % to
20.0%. All areas outside the parking lot, building and sidewalks are assumed to be lawn with an
imperviousness set at 5%.
SUB-BASIN B2
Sub-basin B2 consists of 0.21 acres and is located at the southwest corner of the property and
consists of Detention Pond B. The pond is tributary to Detention Pond A and will outfall into
Pond A prior to exiting the site. In a major storm situation, the stormwater in the Pond A can
back up into Pond B and allows the ponds to be considered one detention pond. The sub-basin
itself includes the pond and the land on the north and east side of the berms. Within the pond
itself, there will be a proposed trickle channel connecting the two FES on the northwest and
southeast sides. The runoff within the basin will outfall into the Pond B trickle channel and will
combine with sub-basin B1 piped flows.
The slope of the bottom of the pond ranges from 2.0% to 5.0% and the slope of the trickle
channel is approximately 0.50%. The side slope of the pond is approximately 25%. The
imperviousness of the concrete sidewalks/walkways is set at 90% and all areas outside the
parking lot, building and sidewalks are assumed to be lawn with an imperviousness set at 5%.
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SUB-BASIN B3
Sub-basin B3 consists of 0.08 acres and is located on the south side of the building within the
subject property. The sub-basin includes a proposed grated manhole and swale. Runoff from
the building sheet falls into the swale and is routed east towards the proposed grated manhole.
The piped flows are routed south through the sub-basin B4 proposed inlet to the A11 proposed
inlet prior to outfalling into Detention Pond A. The slope towards the grated manhole ranges
from 4.0 % to 10.0% with the swale slope ranges from 2.0% to 3.0%. All areas outside the
parking lot, building and sidewalks are assumed to be lawn with an imperviousness set at 5%.
SUB-BASIN B4
Sub-basin B4 consists of 0.14 acres and is located north of the south property entrance of the
subject property. A ridge will stretch from the west side of the property entrance and north to
the sub-basin B5 curb, causing the parking lot to be broken up into two sub-basins. The two
sub-basins will be located on the east and west side of the parking lot, with sub-basin B4 on the
west side. The runoff from the property entrance travels northwest and the runoff on the west
side of the building entrance travels southwest to the inlet prior to outfalling into Detention
Pond A. The piped flows at the inlet will combine with runoff from sub-basins B1 to B3. The
Detention Pond B east ridge is set higher than the sidewalk, directing the runoff on the east side
of the ridge to flow to the parking lot.
The slope of the initial flow across the parking lot is ranges from 2.0 % to 3.0% and the slope
across the sidewalks/pathways ranges from 0.5% to 4.0%. The imperviousness of the asphalt is
set at 100% and the imperviousness of the concrete curb and sidewalks/walkways is set at 90%.
The imperviousness of the roof of the building will be set at 90%.
SUB-BASIN B5
Sub-basin B5 consists of 0.02 acres and is located in the middle of the south parking lot within
the subject property. The lawn within the basin sheet flows to the proposed grated manhole at
the center. The piped flows are routed east through the sub-basin A11 proposed inlet prior to
outfalling into Detention Pond A. The sub-basin runoff is combined with sub-basins B1 to B4
piped flows. The slope towards the grated manhole ranges from 1.0 % to 10.0%. All areas
Windsong at Rock Creek
Final Drainage Report
14
outside the parking lot, building and sidewalks are assumed to be lawn with an imperviousness
set at 5%.
SUB-BASIN C1
Sub-basin C1 consists of 0.06 acres and is located on the west side of the subject property. The
flows are routed offsite and will flow down to the existing curb along Ziegler Road. The existing
curb will then direct the runoff north of the site. The slope of the flow from the sidewalk is
approximately 2.0% and the slope down from the proposed berms is approximately 25%. The
imperviousness of the concrete sidewalks/walkways is set at 90% and all areas outside the
parking lot, building and sidewalks are assumed to be lawn with an imperviousness set at 5%.
SUB-BASIN C2
Sub-basin C2 consists of 0.13 acres and is located on the west side of the subject property. The
flows are routed offsite and will flow down to the existing curb along Ziegler Road. The existing
curb will then direct the runoff south of the site. The slope of the flow from the sidewalk is
approximately 2.0% and the slope down from the proposed berms is approximately 25%. The
runoff at the south entrance flows to the existing curb and is directed east. The imperviousness
of the concrete sidewalks/walkways is set at 90% and all areas outside the parking lot, building
and sidewalks are assumed to be lawn with an imperviousness set at 5%.
SUB-BASIN C3
Sub-basin C3 consists of 0.10 acres and is located on the south side of the subject property.
The flows are directed offsite and will flow down to the existing curb along Rock Creek Drive
roadway. The existing curb will then direct the runoff east of the site. The slope of the flow
from the sidewalk ranges from 2.0% to 8.50% and the slope down from the proposed berms is
approximately 25%. The runoff at the south entrance flows to the existing curb and is directed
east. The imperviousness of the concrete curb and sidewalks/walkways is set at 90% and all
areas outside the parking lot, building and sidewalks are assumed to be lawn with an
imperviousness set at 5%.
Windsong at Rock Creek
Final Drainage Report
15
SUB-BASIN C4
Sub-basin C4 consists of 0.09 acres and is located on the south side of the subject property.
The flows are directed offsite and will flow down to the existing curb along Rock Creek Drive
roadway. The existing curb will then direct the runoff east of the site. The slope of the flow
from the sidewalk is approximately 2.0%. The imperviousness of the asphalt is set at 100% and
the imperviousness of the concrete sidewalks/walkways is set at 90%. All areas outside the
parking lot, building and sidewalks are assumed to be lawn with an imperviousness set at 5%.
SUB-BASIN C5
Sub-basin C5 consists of 0.05 acres and is located on the south side of the subject property.
The flows are directed offsite and will flow down to the existing curb along Rock Creek Drive
roadway. The proposed private roadway creates sheet flow south of the high point and causes
the runoff to flow to the proposed concrete pan. The existing curb will then direct the runoff
east of the site. The slope of the flow from the sidewalk is approximately 2.0% and the slope of
the roadway is approximately 3.0%. The imperviousness of the asphalt is set at 100% and the
imperviousness of the concrete sidewalks/walkways is set at 90%. All areas outside the parking
lot, building and sidewalks are assumed to be lawn with an imperviousness set at 5%.
SUB-BASIN C6
Sub-basin C6 consists of 0.22 acres and is located on the east side of the subject property. The
sub-basin includes the private roadway. The runoff sheet flows east to the flow line and then is
routed to the sump inlet at the low point in the middle of the curb. The collected runoff is
piped east to the proposed sand filter before being piped to the Detention Pond A. The slope
of the roadway cross slope is approximately 2.0% with a longitudinal slope ranging from 0.5% to
2.0%. The cross slope of the sidewalk and lawns are approximately 2.0% and the slope from the
berm is approximately 25%. The imperviousness of the asphalt is set at 100% and the
imperviousness of the concrete sidewalks/walkways is set at 90%. All areas outside the parking
lot, building and sidewalks are assumed to be lawn with an imperviousness set at 5%.
Windsong at Rock Creek
Final Drainage Report
16
DRAINAGE DESIGN CRITERIA
REGULATIONS
This report was prepared to meet or exceed the City of Fort Collins stormwater criteria. The City of
Fort Collins Storm Drainage Design Criteria and Construction Manual (with all current 2011
Revisions)(FCSDDCCM) and the Urban Drainage Flood Control District’s (UDFCD) Drainage Criteria
Manual (USDCM) Volumes 1, 2 and 3 were referenced as guidelines for this design.
MINIMIZATION OF THE DCIA
Volume reduction is an important part of the Four Step Process and is fundamental to effective
stormwater management. Per City criteria, a minimum of 50 percent of new impervious surface area
must be treated by a Low-Impact Development (LID) best management practice (BMP). The proposed
LID BMPs will have the effect of slowing runoff through the site lot and increasing infiltration and rainfall
interception by encouraging infiltration and careful selection of vegetative cover. The improvements will
decrease the runoff coefficient from the site and are expected to have no adverse impact on the timing,
quantity, or quality of stormwater runoff. Site-specific LID BMPs are discussed in the following sections
of this report and an illustrative LID/Surface Map is provided in Appendix E.
DEVELOPMENT CRITERIA REFERENCE AND CONSTRAINTS
The master drainage report for the Windsong at Rock Creek site is the Final Drainage and Erosion Control
Study for Harmony Technology Park Site Master Plan, Fort Collins, Colorado, prepared by Stantec Consulting
Inc., and dated May 21, 2008.
HYDROLOGIC CRITERIA
The rational method was performed to calculate the peak runoff rates for each basin. Weighted percent
imperviousness and weighted runoff coefficients were calculated for each basin using USDCM Tables 6-4
and 6-5 based on Natural Resources Conservation Service (NRCS) Type C hydrologic soil classification
and surface characteristics of each basin. The time of concentration was calculated using USDCM
Equation 6-2 and the intensity was calculated using the corresponding storm rainfall depth and USDCM
Equation RA-3. The City of Fort Collins area has 2-year, 1-hour rainfall depth of 0.82 inches and a 100-
year, 1-hour rainfall depth of 2.86 inches. These depths do account for the 1997 adjusted rainfall depths.
Windsong at Rock Creek
Final Drainage Report
17
HYDRAULIC CRITERIA
This report demonstrates that the proposed stormwater detention concept is able to reduce the 100-
year developed condition flows to the 2-year historical release rates; thereby satisfying the City’s
Reasonable Use requirements. The Rational Formula-based Federal Aviation Administration (FAA)
method is used to size the detention pond in accordance with City criteria, as the tributary area is less
than 20 acres in size. The water quality capture volume is added to the minor and major detention
volumes. An overflow spillway is required at the 100-year water surface elevation, set to flow at no
more than six inches of depth at the peak pond inflow rate, and one foot of freeboard is provided from
the spillway crest to the top of pond.
The ultimate Windsong at Rock Creek storm drainage system will be designed to convey the minor and
major storm events through the property with the proposed inlets, storm sewer pipes, and swales for
the flows being calculated by this report. Per the requirements provided by the City of Fort Collins
Storm Drainage Design Criteria and Construction Manual, all inlets and storm pipes will be designed to
convey the 100-year storm flows. During the major storm event, the developed condition 100-year
storm, the accumulated water depth in the ponds will be held to a maximum level in the ponds of one-
foot below all building finished floor elevations. This drainage report demonstrates that the flow rate
released downstream is less than would historically be experienced, and that the effects of erosion and
sediment transport are lessened through increased infiltration the source.
FLOODPLAIN REGULATIONS COMPLIANCE
The Windsong at Rock Creek site is not located in a regulatory floodplain.
MODIFICATIONS OF CRITERIA
No modifications to City criteria are proposed herein. No variances from City criteria are sought with
this PDP Drainage Report.
Windsong at Rock Creek
Final Drainage Report
18
DRAINAGE FACILITY DESIGN
GENERAL CONCEPT
The proposed improvements to the Windsong site will result in developed condition runoff being
conveyed around the proposed building and to the east via storm sewer and surface flow. Low-impact
development best management practices are proposed to improve the quality of runoff and aid in
reducing peak flows. Specifically, permeable pavement systems are proposed for portions of the parking
lot and drive aisle, and grass lined bio-swales are on the north and west sides of the site to improve
water quality.
Runoff from the site is captured in inlets located in the parking lot and in open areas adjacent to the
building, as well as in the patio courtyard areas. Runoff is conveyed in storm sewers in south and
easterly directions to the proposed pond at the south end of the site. Secondly, surface overflow paths
have been provided, such that the 100-year storm flows remain at least one foot below the finished
floor elevation in a fully clogged inlet condition.
WATER QUALITY/ DETENTION FACILITIES
There currently exists no storm drain outfall that allows the site flows to reach the existing storm drain
system at Rock Creek Drive and Technology Parkway. Outfall concepts are currently being investigated
in collaboration with adjacent landowners, although a specific concept has not been advanced.
Therefore, an extended detention basin has been proposed in lieu of any regional detention located near
Rock Creek Drive and Technology Parkway. The onsite detention pond will provide water quality
treatment and storm peak attenuation, and will release at the 2-year historic discharge to a proposed
outfall pipe on the south end of the Harmony Park site. See Appendix C.
Water quality will be provided for the site through the use of LIDs. Detention will be provided for the
site through the proposed Detention Ponds A and B on the southern edge of the site. In a major storm
situation, the stormwater in the Pond A can back up into Pond B and allows the ponds to be considered
one detention pond. The proposed detention pond will detain the 100 year flows from the site and
release at the 2 year historic release rate to the southeast corner of the property. The 100 yr water
surface elevation and the overflow weir elevation for the pond is at 4920.54. The proposed pond also
has 1 foot of freeboard above this elevation.
Windsong at Rock Creek
Final Drainage Report
19
The most recent version of the UD-Detention software (Version 2.35, January 2015) was used to
determine the ultimate detention volume requirements. Per City of Fort Collins requirements, one-foot
of freeboard is provided in this detention configuration. Since 100% of the site that is tributary to the
ponds is treated by LID water quality is not need in the pond, but the water quality orifice plate will
remain a part the pond’s outlet structure in order to provide redundant water quality treatment. The
design capacity of the onsite pond is the 100-year runoff volume as determined by the FAA method in
accordance with City criteria for a site less than five acres. Although the pond will account for the 40-
hour release of the WQCV, the volume itself is captured upstream and the pond will meet the
detention volume requirement. See Table 1, below, for detention pond sizing and release rates.
Table1: Detention Pond Values
Storage Volume
Required (acre-
ft)
WQCV Volume Required
(acre-ft)
(provided in LIDs)
Storage Volume
Provided (acre-ft)
100-yr Max
Inflow Rate
(cfs)
100-yr Max
Release Rate
(cfs)
0.657 0.07 0.77 21.6 0.5
LOW IMPACT DEVELOPMENT
A minimum of 50 percent of new impervious surface area is treated by a Low-Impact Development
(LID) best management practice (BMP) in accordance with City criteria. The BMPs proposed for the
Windsong site include permeable interlocking concrete pavers, grass swales, and a sand filter for water
quality treatment. Of the total 2.06 acres of impervious area, 1.93 acres is treated by LIDs (93.6%).
Also, the minimum threshold of permeable pavers for new parking is met, with a total of 33.7% of new
parking placed on permeable pavers. An illustrative LID/ Surface Map is provided in Appendix E as well
as sizing of the LIDs/BMPs are provided in Appendix D.
Windsong at Rock Creek
Final Drainage Report
20
Table2: LID Requirements
50% On-Site Treatment by LID Requirement
New Impervious Area 90,031 sq. ft.
Required Minimum Impervious Area to be Treated 45,015 sq. ft.
(=50% of new impervious area)
Area of Paver Section #1 1,190 sq. ft.
Run-on area for Paver Section #1 (8.1:1) 9,633 sq. ft.
Area of Paver Section #2 2,533 sq. ft.
Run-on area for Paver Section #2 (5.1:1) 12,983 sq. ft.
Area of Paver Section #3 7,322 sq. ft.
Run-on area for Paver Section #3 (1.1:1) 8,083 sq. ft.
Impervious Area Treated by LID Treatment Method #1 - Bio-swale #1 9,633 sq. ft.
Impervious Area Treated by LID Treatment Method #2 - Bio-swale #2 12,983 sq. ft.
Impervious Area Treated by LID Treatment Method #3- Sand Filter Pond C 34,555 sq. ft.
Impervious Area Treated by LID Treatment Method #4- Bio-swale #3 2,756 sq. ft.
Impervious Area Treated by LID Treatment Method #5- Bio-swale #4 2,564 sq. ft.
Impervious Area Treated by LID Treatment Method #6- Bio-swale #5 194 sq. ft.
Impervious Area Treated by LID Treatment Method #7- Bio-swale #6 527 sq. ft.
Impervious Area Treated by LID Treatment Method #8- Sand Filter Pond B 12891 sq. ft.
Total Impervious Area Treated 84,186 sq. ft.
Actual % of Porous Pavement Provided 93.5 %
25% Porous Pavement Requirement
New Pavement Area 32,774 sq. ft.
Required Minimum Area of Porous Pavement (=25% of new pavement area) 8,194 sq. ft.
Area of Paver Section #1 1,190 sq. ft.
Area of Paver Section #2 2,533 sq. ft.
Area of Paver Section #3 7,322 sq. ft.
Total Porous Pavement Area 11,045 sq. ft.
Actual % of Porous Pavement Provided 33.7 %
Windsong at Rock Creek
Final Drainage Report
21
CONCLUSIONS
COMPLIANCE WITH STANDARDS
The hydrologic and water quality calculations were performed using the required methods as outlined in
the City of Fort Collins Amendments to the Urban Drainage and Flood Control District Criteria
Manual. The proposed drainage improvements meet or exceed the City’s requirements. This Final
Drainage Report and the complimenting drainage plans and LID plans propose appropriate grading,
permanent landscaping, LID BMPs, and onsite facilities (e.g. storm sewer, inlets, retention/detention
facilities) that are shown in their preliminary configuration and will be designed in the Final Drainage
Report for Windsong at Rock Creek with supporting calculations. This report exhibits that both the
storm water systems meet or exceed the requirements set forth in the City of Fort Collins “Storm
Drainage Criteria Manual and Construction Standards” and addenda.
DRAINAGE CONCEPT
The proposed concept for the development of the Windsong at Rock Creek site involves surface flows
and piping of developed conditions flows to a proposed onsite detention pond. LID site enhancements
will treat the site runoff at the source before allowing the runoff to be conveyed to the proposed
detention pond. Offsite flows from the north will be conveyed through the site and directly released at
the, quality and rate as historically passed through the site. The existing conditions drainage patterns
are maintained in the proposed and future conditions. The proposed improvements will have no adverse
impacts on the flow rate, character, or quality of runoff leaving the site.
Windsong at Rock Creek
Final Drainage Report
22
REFERENCES
East Harmony Portion of McClellands Basin 100-Year Master Plan, Icon Inc., August 1999.
Final Drainage and Erosion Control Study for Harmony Technology Park Site Master Plan, Fort Collins,
Colorado; Stantec Consulting Inc., May 21, 2008.
Hydrologic Group Rating for Larimer County Area, Colorado; USDA-Natural Resources Conservation
Service, National Cooperative Soil Survey, July 21, 2010.
Storm Drainage Criteria Manual and Construction Standards; City of Fort Collins Storm Water Utility,
City of Fort Collins, Colorado, January 1997.
Urban Storm Drainage Criteria Manual (Volumes 1, 2, and 3); Urban Drainage and Flood Control
District, June 2001.
Windsong at Rock Creek
Final Drainage Report
APPENDIX A – FIGURES
;-2(732+ %8 63'/
'6))/ 7-8)
;-2(732+ %8
63'/ '6))/
7-8)
Windsong at Rock Creek
Final Drainage Report
APPENDIX B – HYDROLOGIC CALCULATIONS
Subdivision: 0 Project Name: Windsong
Location: Fort Collins Project No.:
Calculated By: BAB
Checked By: 0
Date: 2/23/16
FINAL
BASIN D.A. Hydrologic Impervious C2 L S
o t i
L t S
o K VEL. t t
COMP. t c TOTAL Urbanized t
c t c
ID (ac) Soils Group (%) (ft) (%) (min) (ft) (%) (ft/s) (min) (min) LENGTH (ft) (min) (min)
EX1 2.99 C 2% 0.10 300 0.7% 35.2 50 0.7% 7.0 0.6 1.4 36.6 350.0 23.3 23.3
EX2 0.17 C 2% 0.10 30 0.5% 12.4 146 0.5% 20.0 1.4 1.7 14.2 176.0 21.0 14.2
EX3 0.19 C 2% 0.10 17 2.4% 5.6 100 0.5% 20.0 1.4 1.2 6.8 117.0 19.9 6.8
OF1 2.30 C 2% 0.10 300 0.8% 33.7 100 0.8% 7.0 0.6 2.7 36.3 400.0 23.7 23.7
* C values based on Table RO-11
NOTES:
t c =t
i +t t
(Equation 6-2)
t i = (0.395*(1.1 - C
5)*(L)^0.5)/((So
)^0.33) (Equation 6-3)
t i = overland (initial) flow time (minutes) K
S = Average Slope along the overland flow path, ft/ft 2.5
t t =L/(60K*(S
o)^0.5 (Equation 6-4) 5
t t = channelized flow time (minutes) 7
S = waterway slope, ft/ft 10
V t = travel time velocity (ft/sec) = K*S
o^0.5 15
20
First Design Point Time of Concentration:
t c =(18-15*i )+L/(60*(24*i +12)*(S
o)^0.5) (Equation 6-5)
i = imperviousness (expressed as a decimal)
t c is lesser of Equation 6-2 and Equation 6-5.
For Urbanized basins a minimum t c of 5.0 minutes is required.
For non-urbanized basins a minimum t c of 10.0 minutes is required.
Paved areas and shallow paved swales
DATA (Ti) (T
t) (URBANIZED BASINS)
Table 6-2. NRCS Conveyance Factors, K
Type of Land Surface
Heavy Meadow
Tillage/field
Short pasture and lawns
Nearly bare ground
Grassed waterway
STANDARD FORM SF-2
TIME OF CONCENTRATION
39727.00
SUB-BASIN INITIAL/OVERLAND TRAVEL TIME tc CHECK
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Project Name: Windsong
Subdivision: 0 Project No.:
Location: Fort Collins Calculated By: BAB
Design Storm: Checked By: 0
Date:
TRAVEL TIME
STREET
Design Point
Basin ID
Area (Ac)
Runoff Coeff.
tc (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
1 OF1 2.30 0.10 23.7 0.23 1.47 0.3
EX1 2.99 0.10 23.3 0.30 1.49 0.4
2 EX2 0.17 0.10 14.2 0.02 1.91 0.03
3 EX3 0.19 0.10 6.8 0.02 2.55 0.05
23.3 0.34 1.49 0.5
DIRECT RUNOFF TOTAL RUNOFF STREET PIPE
STANDARD FORM SF-3
STORM DRAINAGE SYSTEM DESIGN
(RATIONAL METHOD PROCEDURE)
39727.00
2-Year
2/23/16
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Subdivision: 0 Project Name: Windsong
Location: Fort Collins Project No.:
Calculated By: BAB
Checked By: 0
Date: 2/23/16
A1 0.39 100% 0.13 32.7% 90% 0.04 9.3% 5% 0.13 1.7% 90% 0.09 20.9% 64.6%
A2 0.50 100% 0.21 42.1% 90% 0.06 10.5% 5% 0.14 1.4% 90% 0.09 17.1% 71.1%
A3 0.08 100% 0.04 45.1% 90% 0.02 20.3% 5% 0.03 1.6% 90% 0.00 0.0% 67.0%
A4 0.18 100% 0.00 0.0% 90% 0.06 27.5% 5% 0.07 1.8% 90% 0.06 29.9% 59.1%
A5 0.24 100% 0.00 0.0% 90% 0.06 20.5% 5% 0.00 0.0% 90% 0.19 69.5% 90.0%
A6 0.24 100% 0.00 0.0% 90% 0.06 20.5% 5% 0.00 0.0% 90% 0.19 69.5% 90.0%
A7 0.10 100% 0.00 0.0% 90% 0.04 39.2% 5% 0.00 0.0% 90% 0.06 50.8% 90.0%
A8 0.19 100% 0.00 0.0% 90% 0.00 0.0% 5% 0.19 4.9% 90% 0.00 1.9% 6.8%
A9 0.09 100% 0.00 4.1% 90% 0.00 2.9% 5% 0.02 1.0% 90% 0.06 64.5% 72.6%
A10 0.02 100% 0.00 20.9% 90% 0.00 15.2% 5% 0.01 3.1% 90% 0.00 0.0% 39.2%
A11 0.12 100% 0.05 42.9% 90% 0.03 23.9% 5% 0.01 0.6% 90% 0.02 16.8% 84.1%
A12 0.29 100% 0.11 36.4% 90% 0.03 8.0% 5% 0.16 2.7% 90% 0.00 0.0% 47.2%
B1 0.04 100% 0.00 0.0% 90% 0.00 0.0% 5% 0.04 4.5% 90% 0.00 9.2% 13.7%
B2 0.21 100% 0.00 0.0% 90% 0.02 8.3% 5% 0.19 4.5% 90% 0.00 0.0% 12.8%
B3 0.08 100% 0.00 0.0% 90% 0.00 0.0% 5% 0.02 1.5% 90% 0.06 63.6% 65.1%
B4 0.14 100% 0.04 26.8% 90% 0.04 24.7% 5% 0.03 1.0% 90% 0.04 22.9% 75.5%
B5 0.02 100% 0.00 14.6% 90% 0.00 1.4% 5% 0.02 4.2% 90% 0.00 0.0% 20.2%
C1 0.06 100% 0.00 0.0% 90% 0.01 20.7% 5% 0.04 3.8% 90% 0.00 0.0% 24.6%
C2 0.13 100% 0.00 0.0% 90% 0.03 22.6% 5% 0.10 3.7% 90% 0.00 0.0% 26.3%
C3 0.10 100% 0.00 0.0% 90% 0.03 29.7% 5% 0.06 3.3% 90% 0.00 0.0% 33.1%
C4 0.09 100% 0.00 0.0% 90% 0.02 17.7% 5% 0.07 4.0% 90% 0.00 0.0% 21.8%
C5 0.05 100% 0.01 33.1% 90% 0.02 46.4% 5% 0.01 0.8% 90% 0.00 0.0% 80.3%
C6 0.22 100% 0.15 68.3% 90% 0.06 25.6% 5% 0.01 0.2% 90% 0.00 0.0% 94.1%
TOTAL 3.57 60.3%
TOTAL
Pond A & B 3.16 63.9%
TOTAL Pond C
Basin A1-A3,A6-A8,C6 1.73 69.0%
COMPOSITE % IMPERVIOUS CALCULATIONS
Weighted
% Imp.
Basins Total
Weighted %
Basin ID Total Area (ac) % Imp. Area (ac) Imp.
Roofs
% Imp. Area (ac)
Weighted
% Imp.
Paved Roads Concrete Walks/Pavement
% Imp. Area (ac)
Weighted %
Imp.
Lawns
Weighted %
Imp.
% Imp. Area (ac)
39727.00
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Subdivision: 0 Project Name: Windsong
Location: Fort Collins Project No.:
Calculated By: BAB
Checked By: 0
Date: 2/23/16
A1 0.39 0.95 0.13 0.31 0.95 0.04 0.10 0.10 0.13 0.03 0.95 0.09 0.22 0.66
A2 0.50 0.95 0.21 0.40 0.95 0.06 0.11 0.10 0.14 0.03 0.95 0.09 0.18 0.72
A3 0.08 0.95 0.04 0.43 0.95 0.02 0.21 0.10 0.03 0.03 0.95 0.00 0.00 0.68
A4 0.18 0.95 0.00 0.00 0.95 0.06 0.29 0.10 0.07 0.04 0.95 0.06 0.32 0.64
A5 0.24 0.95 0.00 0.00 0.95 0.06 0.22 0.10 0.00 0.00 0.95 0.19 0.73 0.95
A6 0.24 0.95 0.00 0.00 0.95 0.06 0.22 0.10 0.00 0.00 0.95 0.19 0.73 0.95
A7 0.10 0.95 0.00 0.00 0.95 0.04 0.41 0.10 0.00 0.00 0.95 0.06 0.54 0.95
A8 0.19 0.95 0.00 0.00 0.95 0.00 0.00 0.10 0.19 0.10 0.95 0.00 0.02 0.12
A9 0.09 0.95 0.00 0.04 0.95 0.00 0.03 0.10 0.02 0.02 0.95 0.06 0.68 0.77
A10 0.02 0.95 0.00 0.20 0.95 0.00 0.16 0.10 0.01 0.06 0.95 0.00 0.00 0.42
A11 0.12 0.95 0.05 0.41 0.95 0.03 0.25 0.10 0.01 0.01 0.95 0.02 0.18 0.85
A12 0.29 0.95 0.11 0.35 0.95 0.03 0.08 0.10 0.16 0.05 0.95 0.00 0.00 0.49
B1 0.04 0.95 0.00 0.00 0.95 0.00 0.00 0.10 0.04 0.09 0.95 0.00 0.10 0.19
B2 0.21 0.95 0.00 0.00 0.95 0.02 0.09 0.10 0.19 0.09 0.95 0.00 0.00 0.18
B3 0.08 0.95 0.00 0.00 0.95 0.00 0.00 0.10 0.02 0.03 0.95 0.06 0.67 0.70
B4 0.14 0.95 0.04 0.25 0.95 0.04 0.26 0.10 0.03 0.02 0.95 0.04 0.24 0.78
B5 0.02 0.95 0.00 0.14 0.95 0.00 0.01 0.10 0.02 0.08 0.95 0.00 0.00 0.24
C1 0.06 0.95 0.00 0.00 0.95 0.01 0.22 0.10 0.04 0.08 0.95 0.00 0.00 0.30
C2 0.13 0.95 0.00 0.00 0.95 0.03 0.24 0.10 0.10 0.07 0.95 0.00 0.00 0.31
C3 0.10 0.95 0.00 0.00 0.95 0.03 0.31 0.10 0.06 0.07 0.95 0.00 0.00 0.38
C4 0.09 0.95 0.00 0.00 0.95 0.02 0.19 0.10 0.07 0.08 0.95 0.00 0.00 0.27
C5 0.05 0.95 0.01 0.31 0.95 0.02 0.49 0.10 0.01 0.02 0.95 0.00 0.00 0.82
C6 0.22 0.95 0.15 0.65 0.95 0.06 0.27 0.10 0.01 0.00 0.95 0.00 0.00 0.92
TOTAL 3.57 0.63
Area (ac)
Weighted
C2
Runoff
Coefficient
Area (ac)
Weighted
C2
Weighted
C2
Runoff
Coefficient
COMPOSITE % IMPERVIOUS CALCULATIONS
39727.00
Paved Roads Concrete Walks/Pavement Lawns Roofs
Basins Total
Weighted C2
Basin ID
Runoff
Coefficient
Total
Area (ac)
Area (ac)
Weighted
C2
Runoff
Coefficient
Area (ac)
X:\3970000.all\3972700\Excel\Drainage\3972700 Drainage_Calcs_v2.0.xlsm Page 1 of 1 2/16/2016
Subdivision: 0 Project Name: Windsong
Location: Fort Collins Project No.:
Calculated By: BAB
Checked By: 0
Date: 2/23/16
FINAL
BASIN D.A. Hydrologic Impervious C2
C100 L S
o t i
L t S
o K VEL. t t
COMP. t c TOTAL Urbanized t
c t c
ID (ac) Soils Group (%) (ft) (%) (min) (ft) (%) (ft/s) (min) (min) LENGTH (ft) (min) (min)
A1 0.39 C 65% 0.66 0.83 95 8.3% 3.8 74 0.6% 20.0 1.5 0.8 4.6 169.0 9.6 5.0
A2 0.50 C 71% 0.72 0.90 45 1.9% 3.7 148 0.5% 20.0 1.4 1.7 5.5 193.0 8.9 5.5
A3 0.08 C 67% 0.68 0.84 20 25.0% 1.2 25 0.5% 20.0 1.4 0.3 1.5 45.0 8.3 5.0
A4 0.18 C 59% 0.64 0.80 11 16.3% 1.1 152 1.6% 20.0 2.5 1.0 2.1 163.0 9.9 5.0
A5 0.24 C 90% 0.95 1.00 0 13.0% 0.0 117 0.5% 20.0 1.4 1.4 1.4 117.0 5.3 5.0
A6 0.24 C 90% 0.95 1.00 0 13.0% 0.0 121 0.5% 20.0 1.4 1.4 1.4 121.0 5.3 5.0
A7 0.10 C 90% 0.95 1.00 45 20.0% 0.7 75 1.0% 20.0 2.0 0.6 1.3 120.0 5.1 5.0
A8 0.19 C 7% 0.12 0.15 5 16.0% 1.6 3 1.0% 20.0 2.0 0.0 1.6 8.0 17.1 5.0
A9 0.09 C 73% 0.77 0.96 5 8.0% 0.7 65 2.0% 20.0 2.8 0.4 1.1 70.0 7.4 5.0
A10 0.02 C 39% 0.42 0.53 25 4.2% 3.8 0 1.0% 20.0 2.0 0.0 3.8 25.0 12.3 5.0
A11 0.12 C 84% 0.85 1.00 48 2.3% 2.4 38 0.5% 20.0 1.4 0.4 2.8 86.0 6.0 5.0
A12 0.29 C 47% 0.49 0.61 40 8.5% 3.5 17 2.3% 20.0 3.0 0.1 3.6 57.0 11.2 5.0
B1 0.04 C 14% 0.19 0.23 11 16.3% 2.2 62 2.0% 20.0 2.8 0.4 2.5 73.0 16.5 5.0
B2 0.21 C 13% 0.18 0.22 46 5.4% 6.5 90 1.2% 20.0 2.2 0.7 7.2 136.0 17.4 7.2
B3 0.08 C 65% 0.70 0.88 9 4.5% 1.3 81 2.8% 20.0 3.3 0.4 1.7 90.0 8.6 5.0
B4 0.14 C 75% 0.78 0.97 44 2.9% 2.7 28 2.3% 20.0 3.0 0.2 2.9 72.0 6.9 5.0
B5 0.02 C 20% 0.24 0.30 41 2.7% 7.2 0 1.0% 20.0 2.0 0.0 7.2 41.0 15.4 7.2
C1 0.06 C 25% 0.30 0.37 16 2.0% 4.6 0 2.0% 20.0 2.8 0.0 4.6 16.0 14.4 5.0
C2 0.13 C 26% 0.31 0.39 52 7.3% 5.3 0 2.0% 20.0 2.8 0.0 5.3 52.0 14.4 5.3
C3 0.10 C 33% 0.38 0.48 14 2.2% 3.7 60 0.5% 20.0 1.4 0.7 4.5 74.0 13.9 5.0
C4 0.09 C 22% 0.27 0.33 13 2.6% 4.0 0 0.5% 20.0 1.4 0.0 4.0 13.0 14.9 5.0
C5 0.05 C 80% 0.82 1.00 35 25.0% 1.0 30 2.0% 20.0 2.8 0.2 1.2 65.0 6.2 5.0
C6 0.22 C 94% 0.92 1.00 22 2.6% 1.1 0 0.5% 20.0 1.4 0.0 1.1 22.0 4.0 5.0
* C-value determined from composite C value and Table RO-11 and RO-12
NOTES:
t c =t
i +t t
(Equation 6-2)
t i = (0.395*(1.1 - C
5)*(L)^0.5)/((So
)^0.33) (Equation 6-3)
t i = overland (initial) flow time (minutes) K
S = Average Slope along the overland flow path, ft/ft 2.5
t t =L/(60K*(S
o)^0.5 (Equation 6-4) 5
t t = channelized flow time (minutes) 7
S = waterway slope, ft/ft 10
V t = travel time velocity (ft/sec) = K*S
o^0.5 15
20
First Design Point Time of Concentration:
t c =(18-15*i )+L/(60*(24*i +12)*(S
o)^0.5) (Equation 6-5)
i = imperviousness (expressed as a decimal)
t c is lesser of Equation 6-2 and Equation 6-5.
For Urbanized basins a minimum t c of 5.0 minutes is required.
Project Name: Windsong
Subdivision: 0 Project No.:
Location: Fort Collins Calculated By: BAB
Design Storm: Checked By: 0
Date:
TRAVEL TIME
STREET
Design Point
Basin ID
Area (Ac)
Runoff Coeff.
tc (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
Curb cut and bio-swale flow to DP2
1 A1 0.39 0.66 5.0 0.26 2.78 0.7
Curb cut bio-swale flow capture at DP2
2 A2 0.50 0.72 5.5 0.36 2.71 1.0 5.5 0.62 2.71 1.7 1.7 0.5 21 108 3.3 0.5 piped to DP8 Pond C
2'x2' curb sump inlet
3a C6 0.22 0.92 5.0 0.21 2.78 0.6 0.6 0.5 12 26 2.6 0.2 piped to DP3
2'x2' curb sump inlet
3 A3 0.08 0.68 5.0 0.06 2.78 0.2 5.2 0.27 2.76 0.7 0.7 0.5 12 10 2.7 0.1 piped to DP8 Pond C
area sump inlets
6 A6 0.24 0.95 5.0 0.23 2.78 0.6 0.6 0.5 12 120 2.6 0.8 piped to DP7
area sump inlets
7 A7 0.10 0.95 5.0 0.09 2.78 0.3 5.8 0.32 2.67 0.9 0.9 0.5 12 15 2.8 0.1 piped to DP8 Pond C
Sand Filter/ Pond C
8 A8 0.19 0.12 5.0 0.02 2.78 0.1 6.0 1.23 2.64 3.2 3.2 0.5 21 110 4.0 0.5 piped to DP12 Pond A
area sump inlets
5 A5 0.24 0.95 5.0 0.23 2.78 0.6 0.6 0.5 12 120 2.6 0.8 piped to DP4
area sump inlets
4 A4 0.18 0.64 5.0 0.12 2.78 0.3 5.8 0.35 2.67 0.9 0.9 0.5 12 75 2.9 0.4 piped to DP13
area sump inlets
13 B1 0.04 0.19 5.0 0.01 2.78 0.0 6.2 0.36 2.62 0.9 0.9 0.5 12 50 2.9 0.3 piped to DP14 Pond B
WQ Detention Pond B
14 B2 0.21 0.18 7.2 0.04 2.50 0.1 7.2 0.40 2.50 1.0 1.0 0.5 12 10 3.0 0.1 piped to inlet at DP16
area sump inlets
15 B3 0.08 0.70 5.0 0.06 2.78 0.2 0.2 0.5 12 60 1.7 0.6 piped to inlet at DP16
2'x2' curb sump inlet
16 B4 0.14 0.78 5.0 0.11 2.78 0.3 7.2 0.57 2.50 1.4 1.4 0.5 12 40 3.3 0.2 piped to DP17
area sump inlets
17 B5 0.02 0.24 7.2 0.00 2.50 0.0 7.4 0.57 2.47 1.4 1.4 0.5 12 50 3.3 0.3 piped to DP11
area sump inlets
9 A9 0.09 0.77 5.0 0.07 2.78 0.2 0.2 0.5 12 50 1.9 0.4 piped to DP10
area sump inlets
10 A10 0.02 0.42 5.0 0.01 2.78 0.0 5.4 0.08 2.72 0.2 0.2 0.5 12 24 2.0 0.2 piped to DP11
STANDARD FORM SF-3
STORM DRAINAGE SYSTEM DESIGN
(RATIONAL METHOD PROCEDURE)
Project Name: Windsong
Subdivision: 0 Project No.:
Location: Fort Collins Calculated By: BAB
Design Storm: Checked By: 0
Date:
TRAVEL TIME
STREET
Design Point
Basin ID
Area (Ac)
Runoff Coeff.
tc (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
Curb cut and bio-swale flow to DP2
1 A1 0.39 0.83 5.0 0.32 9.70 3.1
Curb cut bio-swale flow capture at DP2
2 A2 0.50 0.90 5.5 0.45 9.46 4.3 5.5 0.77 9.46 7.3 7.3 0.5 21 108 5.0 0.4 piped to DP8 Pond C
2'x2' curb sump inlet
3a C6 0.22 1.00 5.0 0.22 9.70 2.1 2.1 0.5 12 26 3.6 0.1 piped to DP3
2'x2' curb sump inlet
3 A3 0.08 0.84 5.0 0.07 9.70 0.7 5.1 0.29 9.64 2.8 2.8 0.5 12 10 3.6 0.0 piped to DP8 Pond C
area sump inlets
6 A6 0.24 1.00 5.0 0.24 9.70 2.3 2.3 0.5 12 120 3.6 0.6 piped to DP7
area sump inlets
7 A7 0.10 1.00 5.0 0.10 9.70 1.0 5.6 0.34 9.43 3.2 3.2 0.5 12 15 4.1 0.1 piped to DP8 Pond C
Sand Filter/ Pond C
8 A8 0.19 0.15 5.0 0.03 9.70 0.3 5.8 1.43 9.29 13.3 13.3 0.5 21 110 5.5 0.3 piped to DP12 Pond A
area sump inlets
5 A5 0.24 1.00 5.0 0.24 9.70 2.3 2.3 0.5 12 120 3.6 0.6 piped to DP4
area sump inlets
4 A4 0.18 0.80 5.0 0.15 9.70 1.5 5.6 0.39 9.43 3.7 3.7 0.5 12 75 4.7 0.3 piped to DP13
area sump inlets
13 B1 0.04 0.23 5.0 0.01 9.70 0.1 5.8 0.40 9.30 3.7 3.7 0.5 12 50 4.7 0.2 piped to DP14 Pond B
WQ Detention Pond B
14 B2 0.21 0.22 7.2 0.05 8.73 0.4 7.2 0.45 8.73 3.9 3.9 0.5 12 10 5.0 0.0 piped to inlet at DP16
area sump inlets
15 B3 0.08 0.88 5.0 0.07 9.70 0.7 0.7 0.5 12 60 2.7 0.4 piped to inlet at DP16
2'x2' curb sump inlet
16 B4 0.14 0.97 5.0 0.14 9.70 1.4 7.2 0.66 8.72 5.8 5.8 0.5 12 40 7.3 0.1 piped to DP17
area sump inlets
17 B5 0.02 0.30 7.2 0.01 8.72 0.1 7.3 0.67 8.68 5.8 5.8 0.5 12 50 7.4 0.1 piped to DP11
area sump inlets
Windsong at Rock Creek
Final Drainage Report
APPENDIX C – HYDRAULIC CALCULATIONS
Project:
Inlet ID:
Gutter Geometry (Enter data in the blue cells)
Maximum Allowable Width for Spread Behind Curb TBACK
= 23.0 ft
Side Slope Behind Curb (leave blank for no conveyance credit behind curb) SBACK
= 0.250 ft/ft
Manning's Roughness Behind Curb (typically between 0.012 and 0.020) nBACK
= 0.013
Height of Curb at Gutter Flow Line HCURB
= 6.00 inches
Distance from Curb Face to Street Crown TCROWN
= 33.0 ft
Gutter Width W = 2.00 ft
Street Transverse Slope SX
= 0.040 ft/ft
Gutter Cross Slope (typically 2 inches over 24 inches or 0.083 ft/ft) SW
= 0.083 ft/ft
Street Longitudinal Slope - Enter 0 for sump condition SO
= 0.000 ft/ft
Manning's Roughness for Street Section (typically between 0.012 and 0.020) nSTREET
= 0.016
Minor Storm Major Storm
Max. Allowable Spread for Minor & Major Storm TMAX
= 18.0 18.0 ft
Max. Allowable Depth at Gutter Flowline for Minor & Major Storm dMAX
= 6.0 6.0 inches
Allow Flow Depth at Street Crown (leave blank for no) check = yes
MINOR STORM Allowable Capacity is based on Depth Criterion Minor Storm Major Storm
MAJOR STORM Allowable Capacity is based on Depth Criterion Qallow
= SUMP SUMP cfs
Major storm max. allowable capacity GOOD - greater than flow given on sheet 'Q-Peak'
ALLOWABLE CAPACITY FOR ONE-HALF OF STREET (Minor & Major Storm)
DIBC Drainage Improvements
5' Type R Sump Inlet DP3a
(Based on Regulated Criteria for Maximum Allowable Flow Depth and Spread)
Minor storm max. allowable capacity GOOD - greater than flow given on sheet 'Q-Peak'
Sump Inlet DP3a.xlsm, Q-Allow 2/16/2016, 2:08 PM
Project =
Inlet ID =
Design Information (Input) MINOR MAJOR
Type of Inlet Inlet Type =
Local Depression (additional to continuous gutter depression 'a' from 'Q-Allow') alocal
= 3.00 3.00 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) = N/A N/A feet
Width of a Unit Grate Wo
= N/A N/A feet
Area Opening Ratio for a Grate (typical values 0.15-0.90) Aratio
= N/A N/A
Clogging Factor for a Single Grate (typical value 0.50 - 0.70) Cf
(G) = N/A N/A
Grate Weir Coefficient (typical value 2.15 - 3.60) Cw
(G) = N/A N/A
Grate Orifice Coefficient (typical value 0.60 - 0.80) Co
(G) = N/A N/A
Curb Opening Information MINOR MAJOR
Length of a Unit Curb Opening Lo
(C) = 5.00 5.00 feet
Height of Vertical Curb Opening in Inches Hvert
= 6.00 6.00 inches
Height of Curb Orifice Throat in Inches Hthroat
= 6.00 6.00 inches
Angle of Throat (see USDCM Figure ST-5) Theta = 63.40 63.40 degrees
Side Width for Depression Pan (typically the gutter width of 2 feet) Wp
= 2.00 2.00 feet
Clogging Factor for a Single Curb Opening (typical value 0.10) Cf
(C) = 0.10 0.10
Curb Opening Weir Coefficient (typical value 2.3-3.6) Cw
(C) = 3.60 3.60
Curb Opening Orifice Coefficient (typical value 0.60 - 0.70) Co
(C) = 0.67 0.67
MINOR MAJOR
Total Inlet Interception Capacity (assumes clogged condition) Qa
= 5.4 5.4 cfs
Inlet Capacity IS GOOD for Minor and Major Storms (>Q PEAK) Q PEAK REQUIRED
= 0.6 2.1 cfs
INLET IN A SUMP OR SAG LOCATION
DIBC Drainage Improvements
5' Type R Sump Inlet DP3a
CDOT Type R Curb Opening
H-Vert
H-Curb
W
Lo (C)
Lo (G)
Wo
WP
Override Depths
Sump Inlet DP3a.xlsm, Inlet In Sump 2/16/2016, 2:09 PM
Project:
Inlet ID:
Gutter Geometry (Enter data in the blue cells)
Maximum Allowable Width for Spread Behind Curb TBACK
= 23.0 ft
Side Slope Behind Curb (leave blank for no conveyance credit behind curb) SBACK
= 0.250 ft/ft
Manning's Roughness Behind Curb (typically between 0.012 and 0.020) nBACK
= 0.013
Height of Curb at Gutter Flow Line HCURB
= 6.00 inches
Distance from Curb Face to Street Crown TCROWN
= 33.0 ft
Gutter Width W = 2.00 ft
Street Transverse Slope SX
= 0.040 ft/ft
Gutter Cross Slope (typically 2 inches over 24 inches or 0.083 ft/ft) SW
= 0.083 ft/ft
Street Longitudinal Slope - Enter 0 for sump condition SO
= 0.000 ft/ft
Manning's Roughness for Street Section (typically between 0.012 and 0.020) nSTREET
= 0.016
Minor Storm Major Storm
Max. Allowable Spread for Minor & Major Storm TMAX
= 18.0 18.0 ft
Max. Allowable Depth at Gutter Flowline for Minor & Major Storm dMAX
= 6.0 6.0 inches
Allow Flow Depth at Street Crown (leave blank for no) check = yes
MINOR STORM Allowable Capacity is based on Depth Criterion Minor Storm Major Storm
MAJOR STORM Allowable Capacity is based on Depth Criterion Qallow
= SUMP SUMP cfs
Major storm max. allowable capacity GOOD - greater than flow given on sheet 'Q-Peak'
ALLOWABLE CAPACITY FOR ONE-HALF OF STREET (Minor & Major Storm)
DIBC Drainage Improvements
5' Type R Sump Inlet DP3
(Based on Regulated Criteria for Maximum Allowable Flow Depth and Spread)
Minor storm max. allowable capacity GOOD - greater than flow given on sheet 'Q-Peak'
Sump Inlet DP3.xlsm, Q-Allow 2/16/2016, 2:10 PM
Project =
Inlet ID =
Design Information (Input) MINOR MAJOR
Type of Inlet Inlet Type =
Local Depression (additional to continuous gutter depression 'a' from 'Q-Allow') alocal
= 3.00 3.00 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) = N/A N/A feet
Width of a Unit Grate Wo
= N/A N/A feet
Area Opening Ratio for a Grate (typical values 0.15-0.90) Aratio
= N/A N/A
Clogging Factor for a Single Grate (typical value 0.50 - 0.70) Cf
(G) = N/A N/A
Grate Weir Coefficient (typical value 2.15 - 3.60) Cw
(G) = N/A N/A
Grate Orifice Coefficient (typical value 0.60 - 0.80) Co
(G) = N/A N/A
Curb Opening Information MINOR MAJOR
Length of a Unit Curb Opening Lo
(C) = 5.00 5.00 feet
Height of Vertical Curb Opening in Inches Hvert
= 6.00 6.00 inches
Height of Curb Orifice Throat in Inches Hthroat
= 6.00 6.00 inches
Angle of Throat (see USDCM Figure ST-5) Theta = 63.40 63.40 degrees
Side Width for Depression Pan (typically the gutter width of 2 feet) Wp
= 2.00 2.00 feet
Clogging Factor for a Single Curb Opening (typical value 0.10) Cf
(C) = 0.10 0.10
Curb Opening Weir Coefficient (typical value 2.3-3.6) Cw
(C) = 3.60 3.60
Curb Opening Orifice Coefficient (typical value 0.60 - 0.70) Co
(C) = 0.67 0.67
MINOR MAJOR
Total Inlet Interception Capacity (assumes clogged condition) Qa
= 5.4 5.4 cfs
Inlet Capacity IS GOOD for Minor and Major Storms (>Q PEAK) Q PEAK REQUIRED
= 0.2 0.7 cfs
INLET IN A SUMP OR SAG LOCATION
DIBC Drainage Improvements
5' Type R Sump Inlet DP3
CDOT Type R Curb Opening
H-Vert
H-Curb
W
Lo (C)
Lo (G)
Wo
WP
Override Depths
Sump Inlet DP3.xlsm, Inlet In Sump 2/16/2016, 2:10 PM
Project:
Inlet ID:
Gutter Geometry (Enter data in the blue cells)
Maximum Allowable Width for Spread Behind Curb TBACK
= 23.0 ft
Side Slope Behind Curb (leave blank for no conveyance credit behind curb) SBACK
= 0.250 ft/ft
Manning's Roughness Behind Curb (typically between 0.012 and 0.020) nBACK
= 0.013
Height of Curb at Gutter Flow Line HCURB
= 6.00 inches
Distance from Curb Face to Street Crown TCROWN
= 33.0 ft
Gutter Width W = 2.00 ft
Street Transverse Slope SX
= 0.040 ft/ft
Gutter Cross Slope (typically 2 inches over 24 inches or 0.083 ft/ft) SW
= 0.083 ft/ft
Street Longitudinal Slope - Enter 0 for sump condition SO
= 0.000 ft/ft
Manning's Roughness for Street Section (typically between 0.012 and 0.020) nSTREET
= 0.016
Minor Storm Major Storm
Max. Allowable Spread for Minor & Major Storm TMAX
= 18.0 18.0 ft
Max. Allowable Depth at Gutter Flowline for Minor & Major Storm dMAX
= 6.0 6.0 inches
Allow Flow Depth at Street Crown (leave blank for no) check = yes
MINOR STORM Allowable Capacity is based on Depth Criterion Minor Storm Major Storm
MAJOR STORM Allowable Capacity is based on Depth Criterion Qallow
= SUMP SUMP cfs
Major storm max. allowable capacity GOOD - greater than flow given on sheet 'Q-Peak'
ALLOWABLE CAPACITY FOR ONE-HALF OF STREET (Minor & Major Storm)
DIBC Drainage Improvements
5' Type R Sump Inlet DP11
(Based on Regulated Criteria for Maximum Allowable Flow Depth and Spread)
Minor storm max. allowable capacity GOOD - greater than flow given on sheet 'Q-Peak'
Sump Inlet DP11.xlsm, Q-Allow 2/16/2016, 2:12 PM
Project =
Inlet ID =
Design Information (Input) MINOR MAJOR
Type of Inlet Inlet Type =
Local Depression (additional to continuous gutter depression 'a' from 'Q-Allow') alocal
= 3.00 3.00 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) = N/A N/A feet
Width of a Unit Grate Wo
= N/A N/A feet
Area Opening Ratio for a Grate (typical values 0.15-0.90) Aratio
= N/A N/A
Clogging Factor for a Single Grate (typical value 0.50 - 0.70) Cf
(G) = N/A N/A
Grate Weir Coefficient (typical value 2.15 - 3.60) Cw
(G) = N/A N/A
Grate Orifice Coefficient (typical value 0.60 - 0.80) Co
(G) = N/A N/A
Curb Opening Information MINOR MAJOR
Length of a Unit Curb Opening Lo
(C) = 5.00 5.00 feet
Height of Vertical Curb Opening in Inches Hvert
= 6.00 6.00 inches
Height of Curb Orifice Throat in Inches Hthroat
= 6.00 6.00 inches
Angle of Throat (see USDCM Figure ST-5) Theta = 63.40 63.40 degrees
Side Width for Depression Pan (typically the gutter width of 2 feet) Wp
= 2.00 2.00 feet
Clogging Factor for a Single Curb Opening (typical value 0.10) Cf
(C) = 0.10 0.10
Curb Opening Weir Coefficient (typical value 2.3-3.6) Cw
(C) = 3.60 3.60
Curb Opening Orifice Coefficient (typical value 0.60 - 0.70) Co
(C) = 0.67 0.67
MINOR MAJOR
Total Inlet Interception Capacity (assumes clogged condition) Qa
= 5.4 5.4 cfs
Inlet Capacity IS GOOD for Minor and Major Storms (>Q PEAK) Q PEAK REQUIRED
= 0.3 1.2 cfs
INLET IN A SUMP OR SAG LOCATION
DIBC Drainage Improvements
5' Type R Sump Inlet DP11
CDOT Type R Curb Opening
H-Vert
H-Curb
W
Lo (C)
Lo (G)
Wo
WP
Override Depths
Sump Inlet DP11.xlsm, Inlet In Sump 2/16/2016, 2:12 PM
Project:
Inlet ID:
Gutter Geometry (Enter data in the blue cells)
Maximum Allowable Width for Spread Behind Curb TBACK
= 23.0 ft
Side Slope Behind Curb (leave blank for no conveyance credit behind curb) SBACK
= 0.250 ft/ft
Manning's Roughness Behind Curb (typically between 0.012 and 0.020) nBACK
= 0.013
Height of Curb at Gutter Flow Line HCURB
= 6.00 inches
Distance from Curb Face to Street Crown TCROWN
= 33.0 ft
Gutter Width W = 2.00 ft
Street Transverse Slope SX
= 0.040 ft/ft
Gutter Cross Slope (typically 2 inches over 24 inches or 0.083 ft/ft) SW
= 0.083 ft/ft
Street Longitudinal Slope - Enter 0 for sump condition SO
= 0.000 ft/ft
Manning's Roughness for Street Section (typically between 0.012 and 0.020) nSTREET
= 0.016
Minor Storm Major Storm
Max. Allowable Spread for Minor & Major Storm TMAX
= 18.0 18.0 ft
Max. Allowable Depth at Gutter Flowline for Minor & Major Storm dMAX
= 6.0 6.0 inches
Allow Flow Depth at Street Crown (leave blank for no) check = yes
MINOR STORM Allowable Capacity is based on Depth Criterion Minor Storm Major Storm
MAJOR STORM Allowable Capacity is based on Depth Criterion Qallow
= SUMP SUMP cfs
Major storm max. allowable capacity GOOD - greater than flow given on sheet 'Q-Peak'
ALLOWABLE CAPACITY FOR ONE-HALF OF STREET (Minor & Major Storm)
DIBC Drainage Improvements
5' Type R Sump Inlet DP16
(Based on Regulated Criteria for Maximum Allowable Flow Depth and Spread)
Minor storm max. allowable capacity GOOD - greater than flow given on sheet 'Q-Peak'
Sump Inlet DP16.xlsm, Q-Allow 2/16/2016, 2:13 PM
Project =
Inlet ID =
Design Information (Input) MINOR MAJOR
Type of Inlet Inlet Type =
Local Depression (additional to continuous gutter depression 'a' from 'Q-Allow') alocal
= 3.00 3.00 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) = N/A N/A feet
Width of a Unit Grate Wo
= N/A N/A feet
Area Opening Ratio for a Grate (typical values 0.15-0.90) Aratio
= N/A N/A
Clogging Factor for a Single Grate (typical value 0.50 - 0.70) Cf
(G) = N/A N/A
Grate Weir Coefficient (typical value 2.15 - 3.60) Cw
(G) = N/A N/A
Grate Orifice Coefficient (typical value 0.60 - 0.80) Co
(G) = N/A N/A
Curb Opening Information MINOR MAJOR
Length of a Unit Curb Opening Lo
(C) = 5.00 5.00 feet
Height of Vertical Curb Opening in Inches Hvert
= 6.00 6.00 inches
Height of Curb Orifice Throat in Inches Hthroat
= 6.00 6.00 inches
Angle of Throat (see USDCM Figure ST-5) Theta = 63.40 63.40 degrees
Side Width for Depression Pan (typically the gutter width of 2 feet) Wp
= 2.00 2.00 feet
Clogging Factor for a Single Curb Opening (typical value 0.10) Cf
(C) = 0.10 0.10
Curb Opening Weir Coefficient (typical value 2.3-3.6) Cw
(C) = 3.60 3.60
Curb Opening Orifice Coefficient (typical value 0.60 - 0.70) Co
(C) = 0.67 0.67
MINOR MAJOR
Total Inlet Interception Capacity (assumes clogged condition) Qa
= 5.4 5.4 cfs
Inlet Capacity IS GOOD for Minor and Major Storms (>Q PEAK) Q PEAK REQUIRED
= 0.3 1.4 cfs
INLET IN A SUMP OR SAG LOCATION
DIBC Drainage Improvements
5' Type R Sump Inlet DP16
CDOT Type R Curb Opening
H-Vert
H-Curb
W
Lo (C)
Lo (G)
Wo
WP
Override Depths
Sump Inlet DP16.xlsm, Inlet In Sump 2/16/2016, 2:13 PM
Plan View North East
CO-12
CO-11
CO-6
CO-5
CO-4
CO-1
O-3 FES 3-1
O-2 FES 2-1
O-1a FES 1-3
DP3 INLET 3-2
DP3A INLET 3-3
INLET 2A-3
INLET 2A-4
INLET 2A-1
INLET 2A-2
INLET 2-3
DP6 INLET 2-4
DP2 INLET 1-4
DP1 INLET 1-5
DP5 INLET 10A-2
DP7 MH 2-2
27 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA Page 1 of 1
+1-203-755-1666
2/10/2016
Bentley StormCAD V8i (SELECTseries 3)
3972700StormCAD.stsw Bentley Systems, Inc. Haestad Methods Solution Center [08.11.03.84]
Plan View South East
CO-18
CO-17
CO-16
CO-15
CO-14
CO-12
CO-11
CO-6
CO-5
CO-4
O-6 FES 6-1
O-3 FES 3-1
O-2 FES 2-1
O-1 FES 1-1
O-5 EX. INLET 5-1
DP8 PON C OUTLET FES 1-2
DP3 INLET 3-2
DP3A INLET 3-3
INLET 2A-1
INLET 2A-2
INLET 2-3
POND A OTLET 5-6
DP12 INLET 6-2
DP7 MH 2-2
MH 5-5 MH 5-4
MH 5-3
MH 5-2
27 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA Page 1 of 1
+1-203-755-1666
2/10/2016
Bentley StormCAD V8i (SELECTseries 3)
3972700StormCAD.stsw Bentley Systems, Inc. Haestad Methods Solution Center [08.11.03.84]
Plan View South West
CO-25
CO-24
CO-22
CO-21
CO-13
CO-5
CO-4
CO-35
CO-34
O-10 FES 10-1
O-4 FES 4-1
O-6 FES 6-1
INLET 2A-4
INLET 2A-2
INLET 2-3
DP6 INLET 2-4
DP13 INLET 10-2
INLET 10-3
INLET 10-4
INLET 10-6
INLET 10-7
INLET 10-8
DP4 INLET 10A-1
DP5 INLET 10A-2
DP17 INLET 8-1
POND B OUTLET 8-3
DP16 INLET 8-2
DP15 INLET 9-1
DP11 INLET 4-2
DP10 INLET 7-1
DP9 INLET 7-2
DP12 INLET 6-2
MH 10-5
DP7 MH 2-2
27 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA Page 1 of 1
+1-203-755-1666
2/10/2016
Bentley StormCAD V8i (SELECTseries 3)
3972700StormCAD.stsw Bentley Systems, Inc. Haestad Methods Solution Center [08.11.03.84]
2Yr Results
J-loss
Coeff
N-value
Pipe
Velocity
Down
(ft/s)
Velocity
Up
(ft/s)
Velocity
Avg
(ft/s)
EGL
Down
(ft)
EGL Up
(ft)
HGL Down
(ft)
HGL Up
(ft)
Invert
Down
(ft)
Invert Up
(ft)
Line
Slope
(ft/ft)
Line
Length
(ft)
Line
Size
(in)
Capacity
(Design)
(cfs)
Flow
(cfs)
Label
CO-1 0.70 2.93 12.0 177.8 0.004 4,917.85 4,917.14 4,918.20 4,917.75 4,918.33 4,917.78 3.06 2.87 1.38 0.010 1.500
CO-2 1.70 8.60 18.0 108.5 0.004 4,917.14 4,916.71 4,917.63 4,917.16 4,917.81 4,917.39 3.79 3.39 3.79 0.010 0.700
CO-3 3.20 14.65 21.0 110.8 0.005 4,915.68 4,915.12 4,916.33 4,915.68 4,916.57 4,916.04 4.87 3.94 4.87 0.010 0.500
CO-4 0.30 3.26 12.0 50.4 0.005 4,919.60 4,919.35 4,919.83 4,919.56 4,919.90 4,919.66 2.59 2.26 2.59 0.010 1.500
CO-5 0.60 3.27 12.0 66.3 0.005 4,919.15 4,918.82 4,919.47 4,919.17 4,919.59 4,919.26 3.17 2.75 2.49 0.010 0.700
CO-6 0.90 3.23 12.0 22.6 0.005 4,918.62 4,918.51 4,919.02 4,918.87 4,919.17 4,919.06 3.52 3.09 3.52 0.010 1.000
CO-7 0.10 3.27 12.0 22.1 0.005 4,919.23 4,919.12 4,919.36 4,919.24 4,919.40 4,919.29 1.88 1.69 1.88 0.010 1.500
CO-8 0.10 3.21 12.0 20.9 0.005 4,918.92 4,918.82 4,919.17 4,919.17 4,919.17 4,919.17 1.85 0.67 0.41 0.010 0.700
CO-9 0.10 3.23 12.0 30.9 0.005 4,919.29 4,919.14 4,919.42 4,919.26 4,919.46 4,919.31 1.86 1.69 1.86 0.010 1.500
CO-10 0.10 3.27 12.0 24.1 0.005 4,918.94 4,918.82 4,919.16 4,919.17 4,919.17 4,919.17 1.88 0.76 0.41 0.010 0.700
CO-11 0.60 3.26 12.0 28.3 0.005 4,916.39 4,916.25 4,916.71 4,916.54 4,916.83 4,916.70 3.16 2.75 3.16 0.010 1.500
CO-12 0.70 3.18 12.0 16.9 0.005 4,916.05 4,915.97 4,916.40 4,916.29 4,916.53 4,916.45 3.25 2.87 3.24 0.010 0.700
CO-13 1.80 5.87 15.0 12.3 0.005 4,916.50 4,916.44 4,917.03 4,916.93 4,917.24 4,917.18 4.21 3.61 4.08 0.010 0.500
CO-14 0.50 9.78 18.0 164.9 0.009 4,914.96 4,913.53 4,915.22 4,913.76 4,915.31 4,913.89 2.90 2.41 2.90 0.013 0.500
CO-15 0.50 9.68 18.0 317.6 0.009 4,913.33 4,910.63 4,913.59 4,910.86 4,913.68 4,910.99 2.88 2.41 2.88 0.013 0.150
CO-16 0.50 9.69 18.0 301.8 0.009 4,910.43 4,907.86 4,910.69 4,908.09 4,910.78 4,908.22 2.88 2.41 2.88 0.013 0.150
CO-17 0.50 9.51 18.0 11.0 0.008 4,907.66 4,907.57 4,907.92 4,907.80 4,908.01 4,907.93 2.85 2.41 2.85 0.013 0.450
100Yr Results
J-loss
Coeff
N-value
Pipe
Velocity
Down
(ft/s)
Velocity
Up
(ft/s)
Velocity
Avg
(ft/s)
EGL
Down
(ft)
EGL Up
(ft)
HGL Down
(ft)
HGL Up
(ft)
Invert
Down
(ft)
Invert Up
(ft)
Line
Slope
(ft/ft)
Line
Length
(ft)
Line
Size
(in)
Capacity
(Design)
(cfs)
Flow
(cfs)
Label
CO-1 3.10 2.93 12.0 177.8 0.004 4,917.85 4,917.14 4,919.32 4,918.53 4,919.56 4,918.77 3.95 3.95 3.95 0.010 1.500
CO-2 7.30 8.60 18.0 108.5 0.004 4,917.14 4,916.71 4,918.20 4,917.76 4,918.66 4,918.23 5.46 5.46 5.54 0.010 0.700
CO-3 13.30 14.65 21.0 110.8 0.005 4,915.68 4,915.12 4,917.04 4,916.43 4,917.72 4,917.17 6.90 6.64 6.90 0.010 0.500
CO-4 1.20 3.26 12.0 50.4 0.005 4,919.60 4,919.35 4,920.06 4,920.00 4,920.24 4,920.08 3.84 3.38 2.20 0.010 1.500
CO-5 2.30 3.27 12.0 66.3 0.005 4,919.15 4,918.82 4,919.82 4,919.77 4,920.08 4,919.91 4.50 4.10 2.98 0.010 0.700
CO-6 3.20 3.23 12.0 22.6 0.005 4,918.62 4,918.51 4,919.43 4,919.28 4,919.77 4,919.66 4.69 4.72 4.95 0.010 1.000
CO-7 0.25 3.27 12.0 22.1 0.005 4,919.23 4,919.12 4,919.78 4,919.78 4,919.78 4,919.78 2.46 0.57 0.46 0.010 1.500
CO-8 0.50 3.21 12.0 20.9 0.005 4,918.92 4,918.82 4,919.77 4,919.77 4,919.78 4,919.78 2.97 0.70 0.65 0.010 0.700
CO-9 0.25 3.23 12.0 30.9 0.005 4,919.29 4,919.14 4,919.78 4,919.78 4,919.78 4,919.78 2.44 0.66 0.47 0.010 1.500
CO-10 0.50 3.27 12.0 24.1 0.005 4,918.94 4,918.82 4,919.77 4,919.77 4,919.78 4,919.78 3.01 0.72 0.65 0.010 0.700
CO-11 2.10 3.26 12.0 28.3 0.005 4,916.39 4,916.25 4,917.01 4,917.01 4,917.27 4,917.17 4.40 4.11 3.30 0.010 1.500
CO-12 2.80 3.18 12.0 16.9 0.005 4,916.05 4,915.97 4,916.78 4,916.69 4,917.10 4,917.02 4.57 4.57 4.64 0.010 0.700
CO-13 7.70 5.87 15.0 12.3 0.005 4,916.50 4,916.44 4,917.71 4,917.54 4,918.33 4,918.24 6.27 6.33 6.73 0.010 0.500
CO-14 0.50 9.78 18.0 164.9 0.009 4,914.96 4,913.53 4,915.22 4,913.76 4,915.31 4,913.89 2.90 2.41 2.90 0.013 0.500
CO-15 0.50 9.68 18.0 317.6 0.009 4,913.33 4,910.63 4,913.59 4,910.86 4,913.68 4,910.99 2.88 2.41 2.88 0.013 0.150
CO-16 0.50 9.69 18.0 301.8 0.009 4,910.43 4,907.86 4,910.69 4,908.09 4,910.78 4,908.22 2.88 2.41 2.88 0.013 0.150
CO-17 0.50 9.51 18.0 11.0 0.008 4,907.66 4,907.57 4,907.92 4,907.80 4,908.01 4,907.93 2.85 2.41 2.85 0.013 0.450
Windsong at Rock Creek
Final Drainage Report
APPENDIX D – WATER QUALITY/DETENTION CALCULATIONS
Subdivision: 0 Project Name: Windsong
Location: Fort Collins Project No.: 39727.00
Calculated By: BAB
Checked By: 0
Date: 2/23/16
Basin
Area
(ac) % Imp.
A1 0.39 64.6%
A2 0.50 71.1%
A3 0.08 67.0%
A4 0.18 59.1%
A5 0.24 90.0%
A6 0.24 90.0%
A7 0.10 90.0%
A8 0.19 6.8%
A9 0.09 72.6%
A10 0.02 39.2%
A11 0.12 84.1%
A12 0.29 47.2%
B1 0.04 13.7%
B2 0.21 12.8%
B3 0.08 65.1%
B4 0.14 75.5%
B5 0.02 20.2%
C6 0.22 94.1%
Total 3.16 63.9%
WQCV Drain Time (hr): 40
Coefficient, a (Table 3-2): 1.0
WQCV (in): 0.25
WQCV (ac-ft): 0.07
Detention Pond Tributary Areas
WQ Detention/ Basins Treated by LID
X:\3970000.all\3972700\Excel\Drainage\3972700 Drainage_Calcs_v2.0.xlsm Page 1 of 1 2/16/2016
Project:
Basin ID:
Design Information (Input): Design Information (Input):
Catchment Drainage Imperviousness Ia = 63.90 percent Catchment Drainage Imperviousness I
a = 63.90 percent
Catchment Drainage Area A = 3.160 acres Catchment Drainage Area A = 3.160 acres
Predevelopment NRCS Soil Group Type = C A, B, C, or D Predevelopment NRCS Soil Group Type = C A, B, C, or D
Return Period for Detention Control T = 2 years (2, 5, 10, 25, 50, or 100) Return Period for Detention Control T = 100 years (2, 5, 10, 25, 50, or 100)
Time of Concentration of Watershed Tc = 4 minutes Time of Concentration of Watershed Tc = 4 minutes
Allowable Unit Release Rate q = 0.158 cfs/acre Allowable Unit Release Rate q = 0.158 cfs/acre
One-hour Precipitation P1 = 0.82 inches One-hour Precipitation P
1 = 2.86 inches
Design Rainfall IDF Formula i = C1* P1
/(C2+Tc
)^C3 Design Rainfall IDF Formula i = C1
* P1/(C2
+Tc)^C3
Coefficient One C1 = 28.50 Coefficient One C
1 = 28.50
Coefficient Two C2 = 10 Coefficient Two C
2 = 10
Coefficient Three C3 = 0.786 Coefficient Three C
3 = 0.786
Determination of Average Outflow from the Basin (Calculated): Determination of Average Outflow from the Basin (Calculated):
Runoff Coefficient C = 0.44 Runoff Coefficient C = 0.65
Inflow Peak Runoff Qp-in = 4.19 cfs Inflow Peak Runoff Qp-in = 21.60 cfs
Allowable Peak Outflow Rate Qp-out = 0.50 cfs Allowable Peak Outflow Rate Qp-out = 0.50 cfs
Mod. FAA Minor Storage Volume = 3,300 cubic feet Mod. FAA Major Storage Volume = 28,633 cubic feet
Mod. FAA Minor Storage Volume = 0.076 acre-ft Mod. FAA Major Storage Volume = 0.657 acre-ft
5 <- Enter Rainfall Duration Incremental Increase Value Here (e.g. 5 for 5-Minutes)
Rainfall Rainfall Inflow Adjustment Average Outflow Storage Rainfall Rainfall Inflow Adjustment Average Outflow Storage
Duration Intensity Volume Factor Outflow Volume Volume Duration Intensity Volume Factor Outflow Volume Volume
minutes inches / hr acre-feet "m" cfs acre-feet acre-feet minutes inches / hr acre-feet "m" cfs acre-feet acre-feet
(input) (output) (output) (output) (output) (output) (output) (input) (output) (output) (output) (output) (output) (output)
0 0.00 0.000 0.00 0.00 0.000 0.000 0 0.00 0.000 0.00 0.00 0.000 0.000
5 2.78 0.027 0.85 0.43 0.003 0.024 5 9.70 0.137 0.85 0.43 0.003 0.134
10 2.22 0.042 0.68 0.34 0.005 0.038 10 7.74 0.219 0.68 0.34 0.005 0.214
15 1.86 0.053 0.62 0.31 0.006 0.047 15 6.49 0.276 0.62 0.31 0.006 0.269
20 1.61 0.062 0.59 0.29 0.008 0.054 20 5.63 0.318 0.59 0.29 0.008 0.310
25 1.43 0.068 0.57 0.28 0.010 0.059 25 4.98 0.353 0.57 0.28 0.010 0.343
30 1.29 0.074 0.56 0.28 0.012 0.062 30 4.49 0.381 0.56 0.28 0.012 0.369
35 1.17 0.079 0.55 0.27 0.013 0.065 35 4.09 0.405 0.55 0.27 0.013 0.392
40 1.08 0.083 0.54 0.27 0.015 0.068 40 3.77 0.426 0.54 0.27 0.015 0.411
45 1.00 0.086 0.54 0.27 0.017 0.070 45 3.49 0.445 0.54 0.27 0.017 0.428
50 0.94 0.090 0.54 0.27 0.018 0.071 50 3.26 0.462 0.54 0.27 0.018 0.443
55 0.88 0.093 0.53 0.27 0.020 0.072 55 3.06 0.477 0.53 0.27 0.020 0.457
60 0.83 0.095 0.53 0.26 0.022 0.073 60 2.89 0.491 0.53 0.26 0.022 0.469
65 0.78 0.098 0.53 0.26 0.024 0.074 65 2.74 0.503 0.53 0.26 0.024 0.480
70 0.75 0.100 0.53 0.26 0.025 0.075 70 2.60 0.515 0.53 0.26 0.025 0.490
75 0.71 0.102 0.52 0.26 0.027 0.075 75 2.48 0.527 0.52 0.26 0.027 0.500
80 0.68 0.104 0.52 0.26 0.029 0.075 80 2.37 0.537 0.52 0.26 0.029 0.508
85 0.65 0.106 0.52 0.26 0.030 0.076 85 2.27 0.547 0.52 0.26 0.030 0.516
90 0.63 0.108 0.52 0.26 0.032 0.076 90 2.18 0.556 0.52 0.26 0.032 0.524
95 0.60 0.110 0.52 0.26 0.034 0.076 95 2.10 0.565 0.52 0.26 0.034 0.531
100 0.58 0.111 0.52 0.26 0.036 0.076 100 2.03 0.573 0.52 0.26 0.036 0.538
105 0.56 0.113 0.52 0.26 0.037 0.075 105 1.96 0.581 0.52 0.26 0.037 0.544
110 0.54 0.114 0.52 0.26 0.039 0.075 110 1.89 0.589 0.52 0.26 0.039 0.550
115 0.53 0.116 0.52 0.26 0.041 0.075 115 1.83 0.596 0.52 0.26 0.041 0.555
120 0.51 0.117 0.51 0.26 0.042 0.075 120 1.78 0.603 0.51 0.26 0.042 0.561
125 0.49 0.118 0.51 0.26 0.044 0.074 125 1.72 0.610 0.51 0.26 0.044 0.566
Project:
Basin ID:
DETENTION VOLUME BY THE MODIFIED FAA METHOD
Windsong at Rock Creek
Pond A/B
UDFCD DETENTION BASIN VOLUME ESTIMATING WORKBOOK Version 2.35, Released January 2015
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0 50 100 150 200 250 300 350
Volume (acre-feet)
Duration (Minutes)
Inflow and Outflow Volumes vs. Rainfall Duration
Minor Storm Inflow Volume Minor Storm Outflow Volume Minor Storm Storage Volume Major Storm Inflow Volume Major Storm Outflow Volume Major Storm Storage Volume
UD-Detention - Pond A.xls, Modified FAA 2/16/2016, 2:40 PM
Project:
Basin ID:
WQCV Design Volume (Input):
Catchment Imperviousness, Ia = 64.0 percent
Catchment Area, A = 3.16 acres Diameter of holes, D = 0.583 inches
Depth at WQCV outlet above lowest perforation, H = 2.00 feet Number of holes per row, N = 1
Vertical distance between rows, h = 4.00 inches OR
Number of rows, NL = 6.00
Orifice discharge coefficient, Co = 0.62 Height of slot, H = inches
Slope of Basin Trickle Channel, S = 0.005 ft / ft Width of slot, W = inches
Time to Drain the Pond = 40 hours
Watershed Design Information (Input): 2
Percent Soil Type A = %
Percent Soil Type B = %
Percent Soil Type C/D = 100 %
Outlet Design Information (Output):
Water Quality Capture Volume, WQCV = 0.250 watershed inches
Water Quality Capture Volume (WQCV) = 0.07 acre-feet 0.00
Design Volume (WQCV / 12 * Area * 1.2) Vol = 0.07 acre-feet
Outlet area per row, Ao = 0.21 square inches
Total opening area at each row based on user-input above, Ao = 0.27 square inches
Total opening area at each row based on user-input above, Ao = 0.002 square feet
3
Row 1 Row 2 Row 3 Row 4 Row 5 Row 6 Row 7 Row 8 Row 9 Row 10 Row 11 Row 12 Row 13 Row 14 Row 15 Row 16 Row 17 Row 18 Row 19 Row 20 Row 21 Row 22 Row 23 Row 23 6
4918.00 4918.33 4918.67 4919.00 4919.33 4919.67 Flow
4915.00 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.00
4915.50 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.00
4916.00 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.00
4916.50 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.00
4917.01 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.00
4917.07 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.00
4917.50 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.00
4918.00 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.00
4918.50 0.0065 0.0038 0.0000 0.0000 0.0000 0.0000 0.01
4919.00 0.0092 0.0076 0.0053 0.0000 0.0000 0.0000 0.02
4919.50 0.0113 0.0100 0.0084 0.0065 0.0038 0.0000 0.04
4920.00 0.0131 0.0119 0.0107 0.0092 0.0076 0.0053 0.06
4920.54 0.0147 0.0137 0.0126 0.0115 0.0102 0.0086 0.07
4921.00 0.0160 0.0151 0.0141 0.0131 0.0119 0.0107 0.08
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#N/A
Worksheet Protected
Project:
Basin ID:
STAGE-DISCHARGE SIZING OF THE WATER QUALITY CAPTURE VOLUME (WQCV) OUTLET
Windsong at Rock Creek
Pond A
4914.00
4915.00
4916.00
4917.00
4918.00
4919.00
4920.00
4921.00
0.00 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08
Stage (feet, elev.)
Discharge (cfs)
STAGE-DISCHARGE CURVE FOR THE WQCV OUTLET STRUCTURE
UD-Detention - Pond A.xls, WQCV 2/16/2016, 3:18 PM
Project:
Basin ID:
X
1
#1 Vertical #2 Vertical
Sizing the Restrictor Plate for Circular Vertical Orifices or Pipes (Input) Orifice Orifice
Water Surface Elevation at Design Depth Elev: WS = 4,920.54 feet
Pipe/Vertical Orifice Entrance Invert Elevation Elev: Invert = 4,915.00 feet
Required Peak Flow through Orifice at Design Depth Q = 0.50 cfs
Pipe/Vertical Orifice Diameter (inches) Dia = 18.0 inches
Orifice Coefficient Co = 0.63
Full-flow Capacity (Calculated)
Full-flow area Af = 1.77 sq ft
Half Central Angle in Radians Theta = 3.14 rad
Full-flow capacity Qf = 19.4 cfs
Percent of Design Flow = 3886%
Calculation of Orifice Flow Condition
Half Central Angle (0<Theta<3.1416) Theta = 0.49 rad
Flow area Ao = 0.04 sq ft
Top width of Orifice (inches) To = 8.50 inches
Height from Invert of Orifice to Bottom of Plate (feet) Yo = 0.09 feet
Elevation of Bottom of Plate Elev Plate Bottom Edge = 4,915.09 feet
Resultant Peak Flow Through Orifice at Design Depth Qo = 0.5 cfs
Width of Equivalent Rectangular Vertical Orifice Equivalent Width = 0.44 feet
Centroid Elevation of Equivalent Rectangular Vertical Orifice Equiv. Centroid El. = 4,915.05 feet
Windsong at Rock Creek
Pond A
RESTRICTOR PLATE SIZING FOR CIRCULAR VERTICAL ORIFICES
UD-Detention - Pond A.xls, Restrictor Plate 2/16/2016, 3:07 PM
Project:
Basin ID:
Design Information (Input): #1 Horiz. #2 Horiz. #1 Vert. #2 Vert.
Circular Opening: Diameter in Inches Dia. = inches
OR
Rectangular Opening: Width in Feet W = 2.92 0.44 ft.
Length (Height for Vertical) L or H = 2.92 0.09 ft.
Percentage of Open Area After Trash Rack Reduction % open = 65 100 %
Orifice Coefficient Co = 0.63 0.63
Weir Coefficient Cw = 3.00
Orifice Elevation (Bottom for Vertical) Eo = 4917.01 4,915.00 ft.
Calculation of Collection Capacity:
Net Opening Area (after Trash Rack Reduction) Ao = 5.54 0.04 sq. ft.
OPTIONAL: User-Overide Net Opening Area Ao = sq. ft.
Perimeter as Weir Length Lw = 9.64 ft.
OPTIONAL: User-Overide Weir Length Lw = ft.
Top Elevation of Vertical Orifice Opening, Top = 4915.09 ft.
Center Elevation of Vertical Orifice Opening, Cen = 4915.05 ft.
Horizontal Orifices Vertical Orifices
Labels Water WQCV #1 Horiz. #1 Horiz. #2 Horiz. #2 Horiz. #1 Vert. #2 Vert. Total Target Volumes
for WQCV, Minor, Surface Plate/Riser Weir Orifice Weir Orifice Collection Collection Collection for WQCV, Minor,
& Major Storage Elevation Flow Flow Flow Flow Flow Capacity Capacity Capacity & Major Storage
W.S. Elevations ft cfs cfs cfs cfs cfs cfs cfs cfs Volumes
(input) (linked) (User-linked) (output) (output) (output) (output) (output) (output) (output) (link for goal seek)
4915.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
4915.50 0.00 0.00 0.00 0.00 0.00 0.14 0.00 0.00
4916.00 0.00 0.00 0.00 0.00 0.00 0.20 0.00 0.00
4916.50 0.00 0.00 0.00 0.00 0.00 0.24 0.00 0.00
WQCV 4917.01 0.00 0.00 0.00 0.00 0.00 0.28 0.00 0.00
2 YR 4917.07 0.00 0.42 6.81 0.00 0.00 0.29 0.00 0.29
4917.50 0.00 9.92 19.46 0.00 0.00 0.31 0.00 0.31
4918.00 0.00 28.48 27.66 0.00 0.00 0.34 0.00 0.34
4918.50 0.01 52.58 33.93 0.00 0.00 0.37 0.00 0.37
4919.00 0.02 81.15 39.21 0.00 0.00 0.40 0.00 0.40
4919.50 0.04 113.58 43.86 0.00 0.00 0.42 0.00 0.42
4920.00 0.06 149.46 48.07 0.00 0.00 0.45 0.00 0.45
100 YR 4920.54 0.07 191.73 52.23 0.00 0.00 0.47 0.00 0.47
4921.00 0.08 230.40 55.52 0.00 0.00 0.49 0.00 0.49
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Project:
Basin ID:
Windsong at Rock Creek
Pond A/B
STAGE-DISCHARGE SIZING OF THE WEIRS AND ORIFICES (INLET CONTROL)
4915.27
4916.27
4917.27
4918.27
4919.27
4920.27
4921.27
4922.27
0 0.1 0.2 0.3 0.4 0.5 0.6
Stage (feet, elev.)
Discharge (cfs)
STAGE-DISCHARGE CURVE FOR THE OUTLET STRUCTURE
UD-Detention - Pond A.xls, Outlet 2/16/2016, 3:18 PM
Project:
Basin ID:
75.96
4.00000
Design Information (input):
Bottom Length of Weir L = 19.50 feet
Angle of Side Slope Weir Angle = 75.96 degrees
Elev. for Weir Crest EL. Crest = 4,920.54 feet
Coef. for Rectangular Weir Cw = 3.33
Coef. for Trapezoidal Weir Ct = 2.60
Calculation of Spillway Capacity (output):
Water Rect. Triangle Total Total
Surface Weir Weir Spillway Pond
Elevation Flowrate Flowrate Release Release
ft. cfs cfs cfs cfs
(linked) (output) (output) (output) (output)
4915.00 0.00 0.00 0.00 0.00
4915.50 0.00 0.00 0.00 0.00
4916.00 0.00 0.00 0.00 0.00
4916.50 0.00 0.00 0.00 0.00
4917.01 0.00 0.00 0.00 0.00
4917.07 0.00 0.00 0.00 0.00
4917.50 0.00 0.00 0.00 0.00
4918.00 0.00 0.00 0.00 0.00
4918.50 0.00 0.00 0.00 0.00
4919.00 0.00 0.00 0.00 0.00
4919.50 0.00 0.00 0.00 0.00
4920.00 0.00 0.00 0.00 0.00
4920.54 0.00 0.00 0.00 0.00
4921.00 20.26 1.49 21.75 21.75
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Project:
Basin ID:
STAGE-DISCHARGE SIZING OF THE SPILLWAY
Windsong at Rock Creek
Pond A
0 0.2 0.4 0.6 0.8 1
4915.27
4916.27
4917.27
4918.27
4919.27
4920.27
4921.27
4922.27
0 5 10 15 20 25
Storage (Acre-Feet)
Stage (feet, elev.)
Pond Discharge (cfs)
STAGE-STORAGE-DISCHARGE CURVES FOR THE POND
TOTAL DISCHARGE SPILLWAY DISCHARGE POND STORAGE
UD-Detention - Pond A.xls, Spillway 2/16/2016, 3:19 PM
Subdivision: 0 Project Name: Windsong
Location: Fort Collins Project No.: 39727.00
By: BAB
Volume=1/3 x Depth x (A+B+(A*B)^0.5) Checked By: 0
A - Upper Surface Date: 2/23/16
B - Lower Surface
Pond A & B Volume
Stage Stage Elevation Stage Surface Area Stage Volume Cumulative Volume Cumulative Volume
(square feet) (cubic feet) (cubic feet) (acre feet)
0.00 4915.00 7 0 0 0.00
1.00 4916.00 1,671 595 595 0.01
2.00 4917.00 3,291 2,435 3,030 0.07
3.00 4918.00 5,523 4,359 7,389 0.17
4.00 4919.00 8,044 6,744 14,133 0.32
5.00 4920.00 9,507 8,765 22,898 0.53
6.00 4921.00 11,808 10,637 33,535 0.77
Volume (acre feet) Volume Water Surface Elevation
Water Quality 0.07 4917.01
2-Year Detention 0.076 4917.07
100-Year Detention 0.657 4920.54
POND VOLUME CALCULATIONS
X:\3970000.all\3972700\Excel\Drainage\3972700 Drainage_Calcs_v2.0.xlsm Page 1 of 2 2/16/2016
Subdivision: 0 Project Name: Windsong
Location: Fort Collins Project No. 39727.00
By: BAB
Checked By: 0
Date: 2/23/16
POND VOLUME CALCULATIONS
4914.00
4915.00
4916.00
4917.00
4918.00
4919.00
4920.00
4921.00
4922.00
0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90
Elevation (ft)
Pond Volume (ac-ft)
Pond Stage-Storage
X:\3970000.all\3972700\Excel\Drainage\3972700 Drainage_Calcs_v2.0.xlsm Page 2 of 2 2/16/2016
Sheet 1 of 1
Designer:
Company:
Date:
Project:
Location:
1. Design Discharge for 2-Year Return Period Q2 = 0.70 cfs
2. Hydraulic Residence Time
A) : Length of Grass Swale LS = 56.0 ft
B) Calculated Residence Time (based on design velocity below) THR= 1.5 minutes
3. Longitudinal Slope (vertical distance per unit horizontal)
A) Available Slope (based on site constraints) Savail = 0.005 ft / ft
B) Design Slope SD = 0.005 ft / ft
4. Swale Geometry
A) Channel Side Slopes (Z = 4 min., horiz. distance per unit vertical) Z = 4.00 ft / ft
B) Bottom Width of Swale (enter 0 for triangular section) WB = 0.00 ft
5. Vegetation
A) Type of Planting (seed vs. sod, affects vegetal retardance factor)
6. Design Velocity (0.187 ft / s maximum for desirable 5-minute residence time) V2 = 0.62 ft / s
7. Design Flow Depth (1 foot maximum) D2 = 0.53 ft
A) Flow Area A2 = 1.1 sq ft
B) Top Width of Swale WT = 4.2 ft
C) Froude Number (0.50 maximum) F = 0.21
D) Hydraulic Radius RH = 0.26
E) Velocity-Hydraulic Radius Product for Vegetal Retardance VR = 0.16
F) Manning's n (based on SCS vegetal retardance curve E for seeded grass) n = 0.068
G) Cumulative Height of Grade Control Structures Required HD = 0.00 ft
AN UNDERDRAIN IS
8. Underdrain REQUIRED IF THE
(Is an underdrain necessary?) DESIGN SLOPE < 2.0%
9. Soil Preparation
(Describe soil amendment)
10. Irrigation
Notes:
Design Procedure Form: Grass Swale (GS)
JR Engineering
February 18, 2016
Windsong
Bio-swale #1
Choose One
Temporary Permanent
Choose One
Grass From Seed Grass From Sod
Choose One
YES NO
3972700 UD-BMP_v3.03 Bio-Swale.xlsm, GS 2/18/2016, 9:50 AM
Sheet 1 of 1
Designer:
Company:
Date:
Project:
Location:
1. Design Discharge for 2-Year Return Period Q2 = 1.00 cfs
2. Hydraulic Residence Time
A) : Length of Grass Swale LS = 138.0 ft
B) Calculated Residence Time (based on design velocity below) THR= 3.1 minutes
3. Longitudinal Slope (vertical distance per unit horizontal)
A) Available Slope (based on site constraints) Savail = 0.005 ft / ft
B) Design Slope SD = 0.005 ft / ft
4. Swale Geometry
A) Channel Side Slopes (Z = 4 min., horiz. distance per unit vertical) Z = 4.00 ft / ft
B) Bottom Width of Swale (enter 0 for triangular section) WB = 0.00 ft
5. Vegetation
A) Type of Planting (seed vs. sod, affects vegetal retardance factor)
6. Design Velocity (0.46 ft / s maximum for desirable 5-minute residence time) V2 = 0.74 ft / s
7. Design Flow Depth (1 foot maximum) D2 = 0.58 ft
A) Flow Area A2 = 1.3 sq ft
B) Top Width of Swale WT = 4.6 ft
C) Froude Number (0.50 maximum) F = 0.24
D) Hydraulic Radius RH = 0.28
E) Velocity-Hydraulic Radius Product for Vegetal Retardance VR = 0.21
F) Manning's n (based on SCS vegetal retardance curve E for seeded grass) n = 0.062
G) Cumulative Height of Grade Control Structures Required HD = 0.00 ft
AN UNDERDRAIN IS
8. Underdrain REQUIRED IF THE
(Is an underdrain necessary?) DESIGN SLOPE < 2.0%
9. Soil Preparation
(Describe soil amendment)
10. Irrigation
Notes:
Design Procedure Form: Grass Swale (GS)
JR Engineering
February 18, 2016
Windsong
Bio-swale #2
Choose One
Temporary Permanent
Choose One
Grass From Seed Grass From Sod
Choose One
YES NO
3972700 UD-BMP_v3.03 Bio-Swale #2.xlsm, GS 2/18/2016, 9:52 AM
Sheet 1 of 1
Designer:
Company:
Date:
Project:
Location:
1. Design Discharge for 2-Year Return Period Q2 = 0.20 cfs
2. Hydraulic Residence Time
A) : Length of Grass Swale LS = 63.0 ft
B) Calculated Residence Time (based on design velocity below) THR= 2.6 minutes
3. Longitudinal Slope (vertical distance per unit horizontal)
A) Available Slope (based on site constraints) Savail = 0.005 ft / ft
B) Design Slope SD = 0.005 ft / ft
4. Swale Geometry
A) Channel Side Slopes (Z = 4 min., horiz. distance per unit vertical) Z = 4.00 ft / ft
B) Bottom Width of Swale (enter 0 for triangular section) WB = 0.00 ft
5. Vegetation
A) Type of Planting (seed vs. sod, affects vegetal retardance factor)
6. Design Velocity (0.21 ft / s maximum for desirable 5-minute residence time) V2 = 0.41 ft / s
7. Design Flow Depth (1 foot maximum) D2 = 0.35 ft
A) Flow Area A2 = 0.5 sq ft
B) Top Width of Swale WT = 2.8 ft
C) Froude Number (0.50 maximum) F = 0.17
D) Hydraulic Radius RH = 0.17
E) Velocity-Hydraulic Radius Product for Vegetal Retardance VR = 0.07
F) Manning's n (based on SCS vegetal retardance curve E for seeded grass) n = 0.080
G) Cumulative Height of Grade Control Structures Required HD = 0.00 ft
AN UNDERDRAIN IS
8. Underdrain REQUIRED IF THE
(Is an underdrain necessary?) DESIGN SLOPE < 2.0%
9. Soil Preparation
(Describe soil amendment)
10. Irrigation
Notes:
Design Procedure Form: Grass Swale (GS)
JR Engineering
February 18, 2016
Windsong
Bio-swale #3
Choose One
Temporary Permanent
Choose One
Grass From Seed Grass From Sod
Choose One
YES NO
3972700 UD-BMP_v3.03 Bio-Swale #3.xlsm, GS 2/18/2016, 9:59 AM
Sheet 1 of 1
Designer:
Company:
Date:
Project:
Location:
1. Design Discharge for 2-Year Return Period Q2 = 0.20 cfs
2. Hydraulic Residence Time
A) : Length of Grass Swale LS = 70.0 ft
B) Calculated Residence Time (based on design velocity below) THR= 2.9 minutes
3. Longitudinal Slope (vertical distance per unit horizontal)
A) Available Slope (based on site constraints) Savail = 0.005 ft / ft
B) Design Slope SD = 0.005 ft / ft
4. Swale Geometry
A) Channel Side Slopes (Z = 4 min., horiz. distance per unit vertical) Z = 4.00 ft / ft
B) Bottom Width of Swale (enter 0 for triangular section) WB = 0.00 ft
5. Vegetation
A) Type of Planting (seed vs. sod, affects vegetal retardance factor)
6. Design Velocity (0.233 ft / s maximum for desirable 5-minute residence time) V2 = 0.41 ft / s
7. Design Flow Depth (1 foot maximum) D2 = 0.35 ft
A) Flow Area A2 = 0.5 sq ft
B) Top Width of Swale WT = 2.8 ft
C) Froude Number (0.50 maximum) F = 0.17
D) Hydraulic Radius RH = 0.17
E) Velocity-Hydraulic Radius Product for Vegetal Retardance VR = 0.07
F) Manning's n (based on SCS vegetal retardance curve E for seeded grass) n = 0.080
G) Cumulative Height of Grade Control Structures Required HD = 0.00 ft
AN UNDERDRAIN IS
8. Underdrain REQUIRED IF THE
(Is an underdrain necessary?) DESIGN SLOPE < 2.0%
9. Soil Preparation
(Describe soil amendment)
10. Irrigation
Notes:
Design Procedure Form: Grass Swale (GS)
JR Engineering
February 18, 2016
Windsong
Bio-swale #4
Choose One
Temporary Permanent
Choose One
Grass From Seed Grass From Sod
Choose One
YES NO
3972700 UD-BMP_v3.03 Bio-Swale #4.xlsm, GS 2/18/2016, 10:02 AM
Sheet 1 of 1
Designer:
Company:
Date:
Project:
Location:
1. Design Discharge for 2-Year Return Period Q2 = 0.03 cfs
2. Hydraulic Residence Time
A) : Length of Grass Swale LS = 50.0 ft
B) Calculated Residence Time (based on design velocity below) THR= 3.2 minutes
3. Longitudinal Slope (vertical distance per unit horizontal)
A) Available Slope (based on site constraints) Savail = 0.005 ft / ft
B) Design Slope SD = 0.005 ft / ft
4. Swale Geometry
A) Channel Side Slopes (Z = 4 min., horiz. distance per unit vertical) Z = 4.00 ft / ft
B) Bottom Width of Swale (enter 0 for triangular section) WB = 0.00 ft
5. Vegetation
A) Type of Planting (seed vs. sod, affects vegetal retardance factor)
6. Design Velocity (0.167 ft / s maximum for desirable 5-minute residence time) V2 = 0.26 ft / s
7. Design Flow Depth (1 foot maximum) D2 = 0.17 ft
A) Flow Area A2 = 0.1 sq ft
B) Top Width of Swale WT = 1.4 ft
C) Froude Number (0.50 maximum) F = 0.16
D) Hydraulic Radius RH = 0.08
E) Velocity-Hydraulic Radius Product for Vegetal Retardance VR = 0.02
F) Manning's n (based on SCS vegetal retardance curve E for seeded grass) n = 0.080
G) Cumulative Height of Grade Control Structures Required HD = 0.00 ft
AN UNDERDRAIN IS
8. Underdrain REQUIRED IF THE
(Is an underdrain necessary?) DESIGN SLOPE < 2.0%
9. Soil Preparation
(Describe soil amendment)
10. Irrigation
Notes:
Design Procedure Form: Grass Swale (GS)
JR Engineering
February 18, 2016
Windsong
Bio-swale #5
Choose One
Temporary Permanent
Choose One
Grass From Seed Grass From Sod
Choose One
YES NO
3972700 UD-BMP_v3.03 Bio-Swale #5.xlsm, GS 2/18/2016, 10:03 AM
Sheet 1 of 1
Designer:
Company:
Date:
Project:
Location:
1. Design Discharge for 2-Year Return Period Q2 = 0.30 cfs
2. Hydraulic Residence Time
A) : Length of Grass Swale LS = 80.0 ft
B) Calculated Residence Time (based on design velocity below) THR= 3.0 minutes
3. Longitudinal Slope (vertical distance per unit horizontal)
A) Available Slope (based on site constraints) Savail = 0.005 ft / ft
B) Design Slope SD = 0.005 ft / ft
4. Swale Geometry
A) Channel Side Slopes (Z = 4 min., horiz. distance per unit vertical) Z = 4.00 ft / ft
B) Bottom Width of Swale (enter 0 for triangular section) WB = 0.00 ft
5. Vegetation
A) Type of Planting (seed vs. sod, affects vegetal retardance factor)
6. Design Velocity (0.267 ft / s maximum for desirable 5-minute residence time) V2 = 0.45 ft / s
7. Design Flow Depth (1 foot maximum) D2 = 0.41 ft
A) Flow Area A2 = 0.7 sq ft
B) Top Width of Swale WT = 3.3 ft
C) Froude Number (0.50 maximum) F = 0.17
D) Hydraulic Radius RH = 0.20
E) Velocity-Hydraulic Radius Product for Vegetal Retardance VR = 0.09
F) Manning's n (based on SCS vegetal retardance curve E for seeded grass) n = 0.080
G) Cumulative Height of Grade Control Structures Required HD = 0.00 ft
AN UNDERDRAIN IS
8. Underdrain REQUIRED IF THE
(Is an underdrain necessary?) DESIGN SLOPE < 2.0%
9. Soil Preparation
(Describe soil amendment)
10. Irrigation
Notes:
Design Procedure Form: Grass Swale (GS)
JR Engineering
February 18, 2016
Windsong
Bio-swale #6
Choose One
Temporary Permanent
Choose One
Grass From Seed Grass From Sod
Choose One
YES NO
3972700 UD-BMP_v3.03 Bio-Swale #6.xlsm, GS 2/18/2016, 10:04 AM
Sheet 1 of 2
Designer:
Company:
Date:
Project:
Location:
1. Basin Storage Volume
A) Effective Imperviousness of Tributary Area, Ia Ia = 69.0 %
(100% if all paved and roofed areas upstream of sand filter)
B) Tributary Area's Imperviousness Ratio (i = Ia/100) i = 0.690
C) Water Quality Capture Volume (WQCV) Based on 12-hour Drain Time WQCV = 0.24 watershed inches
WQCV= 0.9 * (0.91* i3 - 1.19 * i2 + 0.78 * i)
D) Contributing Watershed Area (including sand filter area) Area = 75,359 sq ft
E) Water Quality Capture Volume (WQCV) Design Volume VWQCV = 1,529 cu ft
VWQCV = WQCV / 12 * Area
F) For Watersheds Outside of the Denver Region, Depth of d6 = 0.43 in
Average Runoff Producing Storm
G) For Watersheds Outside of the Denver Region, VWQCV OTHER = 1,529 cu ft
Water Quality Capture Volume (WQCV) Design Volume
H) User Input of Water Quality Capture Volume (WQCV) Design Volume VWQCV USER = cu ft
(Only if a different WQCV Design Volume is desired)
2. Basin Geometry
A) WQCV Depth DWQCV = 3.00 ft
B) Sand Filter Side Slopes (Horizontal distance per unit vertical, Z = 4.00 ft / ft
4:1 or flatter preferred). Use "0" if sand filter has vertical walls.
C) Mimimum Filter Area (Flat Surface Area) AMin = 340 sq ft
D) Actual Filter Area AActual = 350 sq ft
E) Volume Provided VT = 4614 cu ft
3. Filter Material
4. Underdrain System
A) Are underdrains provided?
B) Underdrain system orifice diameter for 12 hour drain time
i) Distance From Lowest Elevation of the Storage y = 2.0 ft
Volume to the Center of the Orifice
ii) Volume to Drain in 12 Hours Vol12 = 1,529 cu ft
iii) Orifice Diameter, 3/8" Minimum DO = 7 / 8 in
Windsong Fort Collins
Pond C
Design Procedure Form: Sand Filter (SF)
JR Engineering
February 18, 2016
Choose One
Choose One
18" CDOT Class C Filter Material
Other (Explain):
YES
NO
3972700 UD-BMP_v3.03 Pond C Sand Filter.xlsm, SF 2/18/2016, 9:32 AM
Sheet 2 of 2
Designer:
Company:
Date:
Project:
Location:
5. Impermeable Geomembrane Liner and Geotextile Separator Fabric
A) Is an impermeable liner provided due to proximity
of structures or groundwater contamination?
6-7. Inlet / Outlet Works
A) Describe the type of energy dissipation at inlet points and means of
conveying flows in excess of the WQCV through the outlet
Notes:
Design Procedure Form: Sand Filter (SF)
JR Engineering
February 18, 2016
Windsong Fort Collins
Pond C
Choose One
YES NO
3972700 UD-BMP_v3.03 Pond C Sand Filter.xlsm, SF 2/18/2016, 9:32 AM
Sheet 1 of 2
Designer:
Company:
Date:
Project:
Location:
1. Basin Storage Volume
A) Effective Imperviousness of Tributary Area, Ia Ia = 56.7 %
(100% if all paved and roofed areas upstream of sand filter)
B) Tributary Area's Imperviousness Ratio (i = Ia/100) i = 0.567
C) Water Quality Capture Volume (WQCV) Based on 12-hour Drain Time WQCV = 0.20 watershed inches
WQCV= 0.9 * (0.91* i3 - 1.19 * i2 + 0.78 * i)
D) Contributing Watershed Area (including sand filter area) Area = 40,511 sq ft
E) Water Quality Capture Volume (WQCV) Design Volume VWQCV = 685 cu ft
VWQCV = WQCV / 12 * Area
F) For Watersheds Outside of the Denver Region, Depth of d6 = 0.43 in
Average Runoff Producing Storm
G) For Watersheds Outside of the Denver Region, VWQCV OTHER = 685 cu ft
Water Quality Capture Volume (WQCV) Design Volume
H) User Input of Water Quality Capture Volume (WQCV) Design Volume VWQCV USER = cu ft
(Only if a different WQCV Design Volume is desired)
2. Basin Geometry
A) WQCV Depth DWQCV = 3.00 ft
B) Sand Filter Side Slopes (Horizontal distance per unit vertical, Z = 4.00 ft / ft
4:1 or flatter preferred). Use "0" if sand filter has vertical walls.
C) Mimimum Filter Area (Flat Surface Area) AMin = 152 sq ft
D) Actual Filter Area AActual = 1050 sq ft
E) Volume Provided VT = 10508 cu ft
3. Filter Material
4. Underdrain System
A) Are underdrains provided?
B) Underdrain system orifice diameter for 12 hour drain time
i) Distance From Lowest Elevation of the Storage y = 2.0 ft
Volume to the Center of the Orifice
ii) Volume to Drain in 12 Hours Vol12 = 685 cu ft
iii) Orifice Diameter, 3/8" Minimum DO = 9 / 16 in
Windsong Fort Collins
Pond B
Design Procedure Form: Sand Filter (SF)
JR Engineering
February 18, 2016
Choose One
Choose One
18" CDOT Class C Filter Material
Other (Explain):
YES
NO
3972700 UD-BMP_v3.03 Pond B Sand Filter.xlsm, SF 2/18/2016, 9:39 AM
Sheet 2 of 2
Designer:
Company:
Date:
Project:
Location:
5. Impermeable Geomembrane Liner and Geotextile Separator Fabric
A) Is an impermeable liner provided due to proximity
of structures or groundwater contamination?
6-7. Inlet / Outlet Works
A) Describe the type of energy dissipation at inlet points and means of
conveying flows in excess of the WQCV through the outlet
Notes:
Design Procedure Form: Sand Filter (SF)
JR Engineering
February 18, 2016
Windsong Fort Collins
Pond B
Choose One
YES NO
3972700 UD-BMP_v3.03 Pond B Sand Filter.xlsm, SF 2/18/2016, 9:39 AM
Windsong at Rock Creek
Final Drainage Report
APPENDIX E – MAPS
City of Fort Collins, Colorado
UTILITY PLAN APPROVAL
CityDate Engineer
WaterDate & Wastewater Utility
StormwaterDate Utility
ParksDate & Recreation
TrafficDate Engineer Date
EnvironmentalDate Planner
Date
Tributary Area Percent tc Q
2
Sub-basin (acres) Impervious C2 (min) (cfs)
EX1 2.99 2% 0.10 23.3 0.4
EX2 0.17 2% 0.10 14.2 0.0
EX3 0.19 2% 0.10 6.8 0.0
OF1 2.30 2% 0.10 23.7 0.3
Existing BASIN SUMMARY TABLE
City of Fort Collins, Colorado
UTILITY PLAN APPROVAL
CityDate Engineer
WaterDate & Wastewater Utility
StormwaterDate Utility
ParksDate & Recreation
TrafficDate Engineer Date
EnvironmentalDate Planner
Date
Tributary Area Percent tc Q2 Q100
Sub-basin (acres) Impervious C2 C100 (min) (cfs) (cfs)
A1 0.39 65% 0.66 0.83 5.0 0.7 3.1
A2 0.50 71% 0.72 0.90 5.5 1.0 4.2
A3 0.08 67% 0.68 0.84 5.0 0.2 0.7
A4 0.18 59% 0.64 0.80 5.0 0.3 1.4
A5 0.24 90% 0.95 1.00 5.0 0.6 2.3
A6 0.24 90% 0.95 1.00 5.0 0.6 2.3
A7 0.10 90% 0.95 1.00 5.0 0.3 1.0
A8 0.19 7% 0.12 0.15 5.0 0.1 0.3
A9 0.09 73% 0.77 0.96 5.0 0.2 0.8
A10 0.02 39% 0.42 0.53 5.0 0.0 0.1
A11 0.12 84% 0.85 1.00 5.0 0.3 1.1
A12 0.29 47% 0.49 0.61 5.0 0.4 1.7
B1 0.04 14% 0.19 0.23 5.0 0.0 0.1
B2 0.21 13% 0.18 0.22 7.2 0.1 0.4
B3 0.08 65% 0.70 0.88 5.0 0.2 0.7
B4 0.14 75% 0.78 0.97 5.0 0.3 1.4
B5 0.02 20% 0.24 0.30 7.2 0.0 0.1
C1 0.06 25% 0.30 0.37 5.0 0.0 0.2
C2 0.13 26% 0.31 0.39 5.3 0.1 0.5
C3 0.10 33% 0.38 0.48 5.0 0.1 0.4
C4 0.09 22% 0.27 0.33 5.0 0.1 0.3
C5 0.05 80% 0.82 1.00 5.0 0.1 0.4
C6 0.22 94% 0.92 1.00 5.0 0.6 2.2
BASIN SUMMARY TABLE
DETENTION
POND B
DETENTION
POND A
POND C
City of Fort Collins, Colorado
UTILITY PLAN APPROVAL
CityDate Engineer
WaterDate & Wastewater Utility
StormwaterDate Utility
ParksDate & Recreation
TrafficDate Engineer Date
EnvironmentalDate Planner
Date
WINDSONG AT ROCK CREEK
IMPERVIOUS AREA TREATMENT PLAN AREA DESCRIPTION AREA (SF) % OF TOTAL
NEW IMPERVIOUS AREA TREATED BY LID 72,780 81%
PICP AREA 11,406 13%
TOTAL TREATED AREA 84,186 94%
NEW IMPERVIOUS AREA NOT TREATED BY
LID 5,845 6%
TOTAL IMPERVIOUS AREA 90,031 100%
IMPERVIOUS AREA TREATMENT RATIO
City of Fort Collins, Colorado
UTILITY PLAN APPROVAL
CityDate Engineer
WaterDate & Wastewater Utility
StormwaterDate Utility
ParksDate & Recreation
TrafficDate Engineer Date
EnvironmentalDate Planner
Date
New Impervious Area 90,031 sq. ft.
Required Minimum Impervious Area to be Treated 45,015 sq. ft.
(=50% of new impervious area)
Area of Paver Section #1 1,190 sq. ft.
Run-on area for Paver Section #1 (3.7:1) 9,633 sq. ft.
Area of Paver Section #2 2,533 sq. ft.
Run-on area for Paver Section #2 (2.9:1) 12,983 sq. ft.
Area of Paver Section #3 7,322 sq. ft.
Run-on area for Paver Section #3 (1.1:1) 8,083 sq. ft.
Impervious Area Treated by LID Treatment Method #1 - Bio-swale #1 9,633 sq. ft.
Impervious Area Treated by LID Treatment Method #2 - Bio-swale #2 12,983 sq. ft.
Impervious Area Treated by LID Treatment Method #3- Sand Filter Pond C 34,555 sq. ft.
Impervious Area Treated by LID Treatment Method #4- Bio-swale #3 2,756 sq. ft.
Impervious Area Treated by LID Treatment Method #5- Bio-swale #4 2,564 sq. ft.
Impervious Area Treated by LID Treatment Method #6- Bio-swale #5 194 sq. ft.
Impervious Area Treated by LID Treatment Method #7- Bio-swale #6 527 sq. ft.
Impervious Area Treated by LID Treatment Method #8- Sand Filter Pond B 12891 sq. ft.
Total Impervious Area Treated 84,186 sq. ft.
Actual % of Porous Pavement Provided 93.5 %
New Pavement Area 32,774 sq. ft.
Required Minimum Area of Porous Pavement (=25% of new pavement area) 8,194 sq. ft.
Area of Paver Section #1 1,190 sq. ft.
Area of Paver Section #2 2,533 sq. ft.
Area of Paver Section #3 7,322 sq. ft.
Total Porous Pavement Area 11,045 sq. ft.
Actual % of Porous Pavement Provided 33.7 %
50% On-Site Treatment by LID Requirement
25% Porous Pavement Requirement
STAGE-DISCHARGE SIZING OF THE SPILLWAY
Windsong at Rock Creek
Pond A
UD-Detention - Pond A.xls, Spillway 2/16/2016, 3:19 PM
#N/A #N/A #N/A #N/A #N/A #N/A 0.00 #N/A
#N/A #N/A #N/A #N/A #N/A #N/A 0.00 #N/A
#N/A #N/A #N/A #N/A #N/A #N/A 0.00 #N/A
#N/A #N/A #N/A #N/A #N/A #N/A 0.00 #N/A
#N/A #N/A #N/A #N/A #N/A #N/A 0.00 #N/A
#N/A #N/A #N/A #N/A #N/A #N/A 0.00 #N/A
#N/A #N/A #N/A #N/A #N/A #N/A 0.00 #N/A
#N/A #N/A #N/A #N/A #N/A #N/A 0.00 #N/A
Routing 3: Single Stage - Water flows through WQCV plate and #1 horizontal opening into #1 vertical opening. This flow will be applied to
culvert sheet (#2 vertical & horizontal openings is not used).
STAGE-DISCHARGE SIZING OF THE WEIRS AND ORIFICES (INLET CONTROL)
Windsong at Rock Creek
Pond A/B
Current Routing Order is #3
W.S. EL. WQ
W.S. EL. Minor
W.S. EL. Major
WQ
H1
H2
V1 V2
Routing Order #1 (Standard)
V1
W.S. EL. WQ
W.S. EL. Design Storm
WQ
H1
Routing Order #3 (Single Stage) Routing Order #4
V2
V1
H1
WQ
W.S. EL. Major
W.S. EL. Minor
W.S. EL. WQ
W.S. EL. Emergency Spillway
Emergency Overflow into Pipe- H2
V2
H1
WQ
W.S. EL. Major
W.S. EL. Minor
W.S. EL. WQ V1
Routing Order #2
UD-Detention - Pond A.xls, Outlet 2/16/2016, 3:18 PM
#N/A
#N/A
#N/A
#N/A
#N/A
#N/A
#N/A
#N/A
#N/A
Override
Area
Row 1
Override
Area
Row 2
Override
Area
Row 3
Override
Area
Row 4
Override
Area
Row 5
Override
Area
Row 6
Override
Area
Row 7
Override
Area
Row 8
Override
Area
Row 9
Override
Area
Row 10
Override
Area
Row 11
Override
Area
Row 12
Override
Area
Row 13
Override
Area
Row 14
Override
Area
Row 15
Override
Area
Row 16
Override
Area
Row 17
Override
Area
Row 18
Override
Area
Row 19
Override
Area
Row 20
Override
Area
Row 21
Override
Area
Row 22
Override
Area
Row 23
Override
Area
Row 24
Central Elevations of Rows of Holes in feet
Collection Capacity for Each Row of Holes in cfs
STAGE-DISCHARGE SIZING OF THE WATER QUALITY CAPTURE VOLUME (WQCV) OUTLET
Windsong at Rock Creek
Pond A
UD-Detention - Pond A.xls, WQCV 2/16/2016, 3:18 PM
130 0.48 0.120 0.51 0.26 0.046 0.074 130 1.68 0.617 0.51 0.26 0.046 0.571
135 0.47 0.121 0.51 0.26 0.048 0.073 135 1.63 0.623 0.51 0.26 0.048 0.575
140 0.46 0.122 0.51 0.26 0.049 0.073 140 1.59 0.629 0.51 0.26 0.049 0.580
145 0.44 0.123 0.51 0.26 0.051 0.072 145 1.55 0.635 0.51 0.26 0.051 0.584
150 0.43 0.124 0.51 0.26 0.053 0.072 150 1.51 0.641 0.51 0.26 0.053 0.588
155 0.42 0.125 0.51 0.26 0.055 0.071 155 1.47 0.646 0.51 0.26 0.055 0.592
160 0.41 0.126 0.51 0.26 0.056 0.070 160 1.44 0.651 0.51 0.26 0.056 0.595
165 0.40 0.127 0.51 0.25 0.058 0.069 165 1.41 0.657 0.51 0.25 0.058 0.599
170 0.39 0.128 0.51 0.25 0.060 0.069 170 1.38 0.662 0.51 0.25 0.060 0.602
175 0.39 0.129 0.51 0.25 0.061 0.068 175 1.35 0.667 0.51 0.25 0.061 0.605
180 0.38 0.130 0.51 0.25 0.063 0.067 180 1.32 0.672 0.51 0.25 0.063 0.608
185 0.37 0.131 0.51 0.25 0.065 0.066 185 1.29 0.676 0.51 0.25 0.065 0.611
190 0.36 0.132 0.51 0.25 0.067 0.066 190 1.27 0.681 0.51 0.25 0.067 0.614
195 0.36 0.133 0.51 0.25 0.068 0.065 195 1.24 0.685 0.51 0.25 0.068 0.617
200 0.35 0.134 0.51 0.25 0.070 0.064 200 1.22 0.690 0.51 0.25 0.070 0.620
205 0.34 0.135 0.51 0.25 0.072 0.063 205 1.20 0.694 0.51 0.25 0.072 0.622
210 0.34 0.135 0.51 0.25 0.073 0.062 210 1.18 0.698 0.51 0.25 0.073 0.625
215 0.33 0.136 0.51 0.25 0.075 0.061 215 1.15 0.702 0.51 0.25 0.075 0.627
220 0.33 0.137 0.51 0.25 0.077 0.060 220 1.13 0.706 0.51 0.25 0.077 0.629
225 0.32 0.138 0.51 0.25 0.079 0.059 225 1.12 0.710 0.51 0.25 0.079 0.632
230 0.31 0.139 0.51 0.25 0.080 0.058 230 1.10 0.714 0.51 0.25 0.080 0.634
235 0.31 0.139 0.51 0.25 0.082 0.057 235 1.08 0.718 0.51 0.25 0.082 0.636
240 0.30 0.140 0.51 0.25 0.084 0.056 240 1.06 0.722 0.51 0.25 0.084 0.638
245 0.30 0.141 0.51 0.25 0.085 0.055 245 1.05 0.725 0.51 0.25 0.085 0.640
250 0.30 0.141 0.51 0.25 0.087 0.054 250 1.03 0.729 0.51 0.25 0.087 0.642
255 0.29 0.142 0.51 0.25 0.089 0.053 255 1.02 0.732 0.51 0.25 0.089 0.643
260 0.29 0.143 0.51 0.25 0.091 0.052 260 1.00 0.736 0.51 0.25 0.091 0.645
265 0.28 0.143 0.51 0.25 0.092 0.051 265 0.99 0.739 0.51 0.25 0.092 0.647
270 0.28 0.144 0.51 0.25 0.094 0.050 270 0.97 0.743 0.51 0.25 0.094 0.649
275 0.27 0.145 0.51 0.25 0.096 0.049 275 0.96 0.746 0.51 0.25 0.096 0.650
280 0.27 0.145 0.51 0.25 0.097 0.048 280 0.95 0.749 0.51 0.25 0.097 0.652
285 0.27 0.146 0.51 0.25 0.099 0.047 285 0.93 0.752 0.51 0.25 0.099 0.653
290 0.26 0.147 0.51 0.25 0.101 0.046 290 0.92 0.756 0.51 0.25 0.101 0.655
295 0.26 0.147 0.51 0.25 0.103 0.045 295 0.91 0.759 0.51 0.25 0.103 0.656
300 0.26 0.148 0.51 0.25 0.104 0.043 300 0.90 0.762 0.51 0.25 0.104 0.657
Mod. FAA Minor Storage Volume (cubic ft.) = 3,300 Mod. FAA Major Storage Volume (cubic ft.) = 28,633
Mod. FAA Minor Storage Volume (acre-ft.) = 0.0758 Mod. FAA Major Storage Volume (acre-ft.) = 0.6573
DETENTION VOLUME BY THE MODIFIED FAA METHOD
Windsong at Rock Creek
Pond A/B
Determination of MAJOR Detention Volume Using Modified FAA Method
(For catchments less than 160 acres only. For larger catchments, use hydrograph routing method)
(NOTE: for catchments larger than 90 acres, CUHP hydrograph and routing are recommended)
UDFCD DETENTION BASIN VOLUME ESTIMATING WORKBOOK Version 2.35, Released January 2015
Determination of MINOR Detention Volume Using Modified FAA Method
UD-Detention - Pond A.xls, Modified FAA 2/16/2016, 2:40 PM
CO-18 0.50 74.94 42.0 9.0 0.006 4,905.57 4,905.52 4,905.78 4,905.72 4,905.85 4,905.80 2.21 2.13 2.21 0.013 0.450
CO-19 1.70 3.30 12.0 11.8 0.005 4,915.69 4,915.63 4,916.24 4,916.15 4,916.47 4,916.42 4.24 3.80 4.17 0.010 1.500
CO-20 0.90 3.26 12.0 50.3 0.005 4,918.52 4,918.27 4,918.92 4,918.63 4,919.07 4,918.82 3.55 3.09 3.55 0.010 1.500
CO-21 1.00 3.23 12.0 24.7 0.005 4,918.07 4,917.95 4,918.49 4,918.33 4,918.65 4,918.54 3.63 3.20 3.63 0.010 0.700
CO-22 3.90 3.17 12.0 14.9 0.005 4,917.57 4,917.50 4,920.38 4,920.28 4,920.77 4,920.66 4.97 4.97 4.97 0.010 1.500
CO-24 5.80 3.30 12.0 35.5 0.005 4,917.30 4,917.12 4,919.69 4,919.13 4,920.53 4,919.98 7.38 7.38 7.38 0.010 0.700
CO-25 5.80 3.29 12.0 43.6 0.005 4,916.92 4,916.70 4,918.71 4,918.02 4,919.55 4,918.87 7.38 7.38 7.38 0.010 0.500
CO-26 0.70 3.28 12.0 56.0 0.005 4,919.03 4,918.75 4,920.29 4,920.28 4,920.30 4,920.29 0.89 0.89 0.89 0.010 1.500
CO-27 0.03 3.21 12.0 20.9 0.005 4,919.83 4,919.73 4,920.65 4,920.65 4,920.65 4,920.65 1.22 0.04 0.03 0.010 1.500
CO-28 0.05 3.36 12.0 26.6 0.005 4,919.53 4,919.39 4,920.65 4,920.65 4,920.65 4,920.65 0.06 0.06 0.06 0.010 0.700
CO-29 0.08 3.25 12.0 16.3 0.005 4,919.19 4,919.11 4,920.65 4,920.65 4,920.65 4,920.65 0.10 0.10 0.10 0.010 0.500
CO-30 3.70 3.20 12.0 27.3 0.005 4,918.91 4,918.78 4,920.30 4,920.13 4,920.65 4,920.47 4.71 4.71 4.71 0.010 1.000
CO-31 3.70 3.28 12.0 27.9 0.005 4,918.58 4,918.44 4,919.61 4,919.43 4,919.95 4,919.78 4.71 4.71 4.72 0.010 1.500
CO-32 3.70 3.28 12.0 20.0 0.005 4,918.24 4,918.14 4,919.18 4,919.06 4,919.54 4,919.43 4.71 4.83 4.90 0.010 0.700
CO-33 3.70 3.29 12.0 51.5 0.005 4,917.94 4,917.68 4,918.88 4,918.50 4,919.24 4,918.95 4.71 4.84 5.37 0.010 0.500
CO-34 2.30 3.26 12.0 50.4 0.005 4,919.89 4,919.64 4,921.44 4,921.31 4,921.57 4,921.44 2.93 2.93 2.93 0.010 1.500
CO-35 3.70 3.27 12.0 66.3 0.005 4,919.44 4,919.11 4,921.07 4,920.65 4,921.41 4,920.99 4.71 4.71 4.71 0.010 0.700
27 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203- Page 1 of 1
755-1666
2/10/2016
Bentley StormCAD V8i (SELECTseries 3)
3972700StormCAD.stsw Bentley Systems, Inc. Haestad Methods Solution Center [08.11.03.84]
CO-18 0.50 74.94 42.0 9.0 0.006 4,905.57 4,905.52 4,905.78 4,905.72 4,905.85 4,905.80 2.21 2.13 2.21 0.013 0.450
CO-19 0.40 3.30 12.0 11.8 0.005 4,915.69 4,915.63 4,915.95 4,915.87 4,916.04 4,915.99 2.84 2.45 2.83 0.010 1.500
CO-20 0.20 3.26 12.0 50.3 0.005 4,918.52 4,918.27 4,918.70 4,918.44 4,918.77 4,918.52 2.30 2.02 2.30 0.010 1.500
CO-21 0.20 3.23 12.0 24.7 0.005 4,918.07 4,917.95 4,918.25 4,918.12 4,918.32 4,918.20 2.29 2.02 2.29 0.010 0.700
CO-22 1.00 3.17 12.0 14.9 0.005 4,917.57 4,917.50 4,917.99 4,917.94 4,918.15 4,918.08 3.58 3.20 3.02 0.010 1.500
CO-24 1.40 3.30 12.0 35.5 0.005 4,917.30 4,917.12 4,917.80 4,917.57 4,918.00 4,917.83 4.03 3.56 4.03 0.010 0.700
CO-25 1.40 3.29 12.0 43.6 0.005 4,916.92 4,916.70 4,917.42 4,917.16 4,917.62 4,917.41 4.02 3.56 4.02 0.010 0.500
CO-26 0.20 3.28 12.0 56.0 0.005 4,919.03 4,918.75 4,919.21 4,918.92 4,919.28 4,919.00 2.31 2.02 2.31 0.010 1.500
CO-27 0.01 3.21 12.0 20.9 0.005 4,919.83 4,919.73 4,919.87 4,919.77 4,919.88 4,919.78 0.92 0.92 0.94 0.010 1.500
CO-28 0.02 3.36 12.0 26.6 0.005 4,919.53 4,919.39 4,919.59 4,919.46 4,919.61 4,919.47 1.17 1.12 0.89 0.010 0.700
CO-29 0.03 3.25 12.0 16.3 0.005 4,919.19 4,919.11 4,919.46 4,919.46 4,919.46 4,919.46 1.30 0.18 0.12 0.010 0.500
CO-30 0.90 3.20 12.0 27.3 0.005 4,918.91 4,918.78 4,919.31 4,919.20 4,919.46 4,919.33 3.49 3.09 2.87 0.010 1.000
CO-31 0.90 3.28 12.0 27.9 0.005 4,918.58 4,918.44 4,918.98 4,918.80 4,919.13 4,919.00 3.56 3.09 3.56 0.010 1.500
CO-32 0.90 3.28 12.0 20.0 0.005 4,918.24 4,918.14 4,918.64 4,918.50 4,918.79 4,918.69 3.56 3.09 3.54 0.010 0.700
CO-33 0.90 3.29 12.0 51.5 0.005 4,917.94 4,917.68 4,918.34 4,918.04 4,918.49 4,918.24 3.57 3.09 3.57 0.010 0.500
CO-34 0.60 3.26 12.0 50.4 0.005 4,919.89 4,919.64 4,920.21 4,919.93 4,920.33 4,920.09 3.17 2.75 3.17 0.010 1.500
CO-35 0.90 3.27 12.0 66.3 0.005 4,919.44 4,919.11 4,919.84 4,919.47 4,919.99 4,919.67 3.55 3.09 3.55 0.010 0.700
27 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203- Page 1 of 1
755-1666
2/10/2016
Bentley StormCAD V8i (SELECTseries 3)
3972700StormCAD.stsw Bentley Systems, Inc. Haestad Methods Solution Center [08.11.03.84]
9 A9 0.09 0.96 5.0 0.09 9.70 0.9 0.9 0.5 12 50 2.9 0.3 piped to DP10
area sump inlets
10 A10 0.02 0.53 5.0 0.01 9.70 0.1 5.3 0.10 9.56 1.0 1.0 0.5 12 24 3.0 0.1 piped to DP11
2'x2' curb sump inlet
11 A11 0.12 1.00 5.0 0.12 9.70 1.2 7.4 0.89 8.64 7.7 7.7 0.5 15 12 6.3 0.0 piped to DP12 Pond A
WQ Detention Pond A
12 A12 0.29 0.61 5.0 0.18 9.70 1.7 7.4 2.50 8.62 21.6 piped to offsite MH
18 C1 0.06 0.37 5.0 0.02 9.70 0.2
0.6 0.5 594 1.5 6.4
19 C2 0.13 0.39 5.3 0.05 9.54 0.5
0.6 0.5 400 1.5 4.3 Runoff flows south to Rock Creek Drive
C3 0.10 0.48 5.0 0.05 9.70 0.5 than directed east
1.0 0.3 190 2.0 1.6 Runoff flows south to Rock Creek Drive
C4 0.09 0.33 5.0 0.03 9.70 0.3 than directed east
Street flow offsite
C5 0.05 1.00 5.0 0.05 9.70 0.5 11.7 0.18 7.26 1.3
Runoff flows to Ziegler Roand and North offsite
Runoff flows to Ziegler Roand andsouth to Rock
Creek Drive then directed east
39727.00
PIPE
100-Year
DIRECT RUNOFF TOTAL RUNOFF STREET
2/23/16
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2'x2' curb sump inlet
11 A11 0.12 0.85 5.0 0.10 2.78 0.3 7.7 0.75 2.45 1.8 1.8 0.5 15 12 3.5 0.1 piped to DP12 Pond A
WQ Detention Pond A
12 A12 0.29 0.49 5.0 0.14 2.78 0.4 7.7 2.12 2.44 5.2 piped to offsite MH
18 C1 0.06 0.30 5.0 0.02 2.78 0.1
0.6 0.1 594 1.5 6.4
19 C2 0.13 0.31 5.3 0.04 2.74 0.1
0.6 0.1 400 1.5 4.3 Runoff flows south to Rock Creek Drive
C3 0.10 0.38 5.0 0.04 2.78 0.1 than directed east
1.0 0.1 190 2.0 1.6 Runoff flows south to Rock Creek Drive
C4 0.09 0.27 5.0 0.02 2.78 0.1 than directed east
Street flow offsite
C5 0.05 0.82 5.0 0.04 2.78 0.1 11.7 0.14 2.08 0.3
Runoff flows to Ziegler Roand and North offsite
Runoff flows to Ziegler Roand andsouth to Rock
Creek Drive then directed east
DIRECT RUNOFF TOTAL RUNOFF STREET PIPE
2/23/16
STANDARD FORM SF-3
STORM DRAINAGE SYSTEM DESIGN
(RATIONAL METHOD PROCEDURE)
2-Year
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For non-urbanized basins a minimum t c of 10.0 minutes is required.
DATA (URBANIZED BASINS)
INITIAL/OVERLAND
(Ti)
TRAVEL TIME
(Tt)
STANDARD FORM SF-2
TIME OF CONCENTRATION
SUB-BASIN tc CHECK
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Table 6-2. NRCS Conveyance Factors, K
Nearly bare ground
Grassed waterway
Paved areas and shallow paved swales
Type of Land Surface
Heavy Meadow
Tillage/field
Short pasture and lawns
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