HomeMy WebLinkAboutDrainage Reports - 06/25/2018A CTION CIVIL ENGINEERING LL C
City of Ft Col�r'rr pr ed Plans
Approved By
Date
FINAL DRAINAGE REPORT
Fort Collins Jeep Dealership
Fort Collins, Colorado
Project #PDP170013
April, 2018
PREPARED FOR:
Commercial Building Services
7561 S. Grant Street, Suite A-4
Littleton, CO 80122
Contact: Steve Morel
(303) 730-3001
PREPARED BY. -
ACTION CIVIL ENGINEERING
11600 Whooping Crane Drive
Parker, CO, CO. 80134
(720) 260-0433
ACE Project No. 16-018
ITable of Contents
I. GENERAL LOCATION AND DESCRIPTION............................................................. 2
A. 'Site Location.................................................................................................................... 2
B. Description of Property.................................................................................................... 3
C. Floodplain Submittal Requirements................................................................................. 4
II. MAJOR DRAINAGE BASINS AND SUB -BASINS ...................................................... 4
A. Major Drainage Basins..................................................................................................... 4
B. Sub-basins........................................................................................................................ 4
III. DRAINAGE DESIGN CRITERIA.................................................................................. 6
A. Regulations.......................................................................................................................6
B. Directly Connected Impervious Area............................................................................... 6
I C. 'Development Criteria Reference and Constraints............................................................ 6
D. Hydrologic Criteria.......................................................................................................... 6
E. Hydraulic Criteria ............................................ :................................................................ 7
■ F. Floodplain Regulations Compliance................................................................................ 7
G. Modifications of Criteria.................................................................................................. 7
IV. DRAINAGE FACILITY DESIGN................................................................................... 7
IA. General Concept............................................................................................................... 7
B. Specific Details................................................................................................................ 8
V. CONCLUSIONS................................................................................................................ 8
' VI. REFERENCES...................................................................................................................8
Appendix A — Vicinity Map, Soils Map, Floodplain Checklist
Appendix B — Hydrologic Computations
Appendix C — Hydraulic Calculations
Action Civil Engineering LLC Page 1
I. GENERAL LOCATION AND DESCRIPTION
A. Site Location
' Fort Collins Jeep Dealership is located on a site currently containing 4.48 acres northwest of the
intersection of South Mason Street and West County Road 38 in the City of Fort Collins, Larimer
County, Colorado. The site lies in the Southeast 1/4 of Section 35, Township 7 North, Range 69
' West of the 5t' Principal Meridian. It is bounded on the north by an existing car dealership
(Pedersen Volvo), on the east by South Mason Street with existing commercial development
beyond, on the south by existing West.County Road 38, with existing educational development
' beyond, and on the west by existing bus road, with railroad with existing railway, greenbelt and
residential area beyond.
1 Action Civil Engineering LLC Page 2
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VICINITY MAP
NO SCALE
B. Description of Property
The existing site was built as a lumber yard, but has not been used for that purpose for some time.
Detention appears not to have been required for the site when it was built in 1974, as none is in
evidence.
Action Civil Engineering LLC Page 1
The current area of the project site is 4.48 acres. However, South Mason Street is slated for
"midtown" redevelopment, and an additional 0.13 acres of additional right-of-way is being
requested by the City of Fort Collins to expand South Mason Street.
' A lot to the west of the project site, separate from the project site but owned by the same owner,
is 0.87 acres, and contains of two structures and a parking lot consisting of soil and vegetation.
No development, staging, or storage of materials will occur on this lot as related to this project.
The main building of the site will remain (will be remodeled), with two areas of expansion, one
on the west side of the building, and one on the north. An outdoor lumber storage area on the east
side of the existing building will be removed, as well as a raised concrete loading dock on the west
side of the site and other concrete pad areas. The aging pavement on the site will be removed and
replaced. The proposed use is car dealership.
Soils on the site, according to USDA National Soil Conservation website, consist of Nunn clay
loam- Hydrologic Soil Type C (94% of site) with a small area of Altvan-Satanta loams (6%) —
Hydrologic Soil Type B, in the northeast corner of the site. Fort Collins Jeep Dealership is located
outside the 100-year floodplain, according to FEMA FIRM map panel 08069C1000F (Map Panel
Not Printed.)
C. Floodplain Submittal Requirements
Fort Collins Jeep Dealership is located outside the 100-year floodplain, according to FEMA FIRM
' map panel 08069C 1000F (Map Panel Not Printed). See "City of Fort Collins Floodplain Review
Checklist 50% Development Review Submittals" in Appendix A.
II. MAJOR DRAINAGE BASINS AND SUB -BASINS
A. Major Drainage Basins
The site is located within the Mail Creek Basin, a basin of approximately 1,676 acres in southwest
Fort Collins. To the east of the site is College Avenue, which runs north -south and consists of
commercial development along the length. The remainder of the basin consists of mixed -use
residential development. The basin generally drains west to east to the confluence of Mail Creek
and Fossil Creek, and ultimately to Fossil Creek Reservoir. (City of Fort Collins 2017)
B. Sub -basins
The current drainage pattern consists of a large shallow swale within the west parking area of the
site, which directs runoff south to W. County Road 38 via an existing sidewalk chase. The east
side of the site slopes to the east from the east side of the main building, towards South Mason
Street via a drive entrance located near the south end of the South Mason Street frontage. Both
streets drain to the intersection of South County Road 38, and South Mason Street to an existing
10' Type R inlet located on the South Mason Street side of the intersection. This inlet will be
moved west approximately 7' to be in line with the proposed street widening of South Mason
Action Civil Engineering LLC Page 4
Street There is also a low area in the southwest corner of the site, with no apparent outlet.
Proposed Sub -basins
The proposed grading will follow a similar pattern. The entrance locations will both change. The
W. County Road 38 entrance will be reduced in width to accommodate a bus pullout proposed to
be built immediately west of the drive (eliminating traffic hazard from buses stopping in the lane
of this busy street.)
The South Mason Street entrance will be moved approximately 300 feet north to near the northeast
comer of the site. The runoff which previously drained to the entrance will be re-routed to South
' Mason Street with a small channel and chase section located near the southeast corner of the new
proposed parking lot.
A low area in the southwest corner of the site, with no apparent outlet, will be raised such that the
runoff can be directed to the sidewalk chase at the low point in the parking area east of the West
County Road 38 drive entrance.
Proposed Basin A (0.22 acres of pavement) sheet flows to a 2-foot wide concrete pan which directs
runoff to Bioretention Pond A.
Proposed Basin B (0.33 acres of pavement) sheet flows to a 2-foot wide concrete pan which directs
runoff to Bioretention Pond B.
Proposed Basin C (1.72 acres of pavement and roof) sheet flows to a 2-foot wide concrete pan
which directs runoff to Bioretention Pond C.
Proposed Basin D (0.15 acres of pavement) sheet flows to a 2-foot wide sidewalk chase which
' directs runoff to the north flowline of West Harmony Road. Runoff then flows east to the relocated
Type R inlet at the NW corner of West Harmony Road and South Mason Street.
' Proposed Basin E (0.39 acres of pavement and roof) sheet flows to a 2-foot wide sidewalk chase
which directs runoff to the west flowline of South Mason Street. Runoff the flows south to the
relocated Type R inlet at the NW corner of West Harmony Road and South Mason Street.
Proposed Basin F (0.42 acres of pavement and roof) sheet flows to a 2-foot wide sidewalk chase
which directs runoff to the west flowline of South Mason Street. Runoff the flows south to the
relocated Type R inlet at the NW corner of West Harmony Road and South Mason Street.
Proposed Basin G (0.56 acres of pavement and roof) sheet flows to a 2-foot wide sidewalk chase
which directs runoff to the north flowline of West Harmony Road. Runoff then flows east to the
relocated Type R inlet at the NW corner of West Harmony Road and South Mason Street.
' Existin¢ Off -site Sub -basins
Existing Basin H (0.08 acres of soil and vegetation) is within the lot to the west of the site. The
sub -basin is ungraded, and runoff sheet flows to the northeast and offsite toward the railroad track.
No development will occur within Basin H as a part of this project.
Action Civil Engineering LLC Page 5
Existing Basin I (0.49 acres of soil and vegetation) is within the lot to the west of the site. The sub -
basin is ungraded, and runoff sheet flows to the east and southeast offsite, and eventually to a low
point adjacent to the railroad track. Most runoff is collected by a channel to the east of the basin
' and flows south to the low point. The remainder of runoff flows directly to the low point. No
development will occur within Basin I as a part of this project.
' Existing Basin J (0.09 acres of soil and vegetation) is within the lot to the west of the site. The sub -
basin is ungraded, and runoff sheet slows to the south offsite, to West Harmony Road, and
eventually to the 10' Type R inlet at the intersection of West Harmony Road and South Mason St.
' No development will occur within Basin J as a part of this project.
' III. DRAINAGE DESIGN CRITERIA
' A. Regulations
The design of the proposed stormwater management system was done in compliance with Fort
Collins Amendments to the Urban Drainage and Flood Control District, Urban Storm Drainage
Criteria Manual Volumes 1, 2 and 3. (UDFCD 2017)
When improvements are proposed to an existing developed site and there is an increase in
impervious area greater than 1000 square feet, onsite detention is required. The existing site
impervious area is 158,473 square feet and the proposed impervious area is 159,188 resulting in a
net increase in impervious area of 715 square feet therefore detention is not required. Low Impact
Development (LID) requirements are required on all redeveloped property. 75% of all newly added
or modified impervious are must be treated by LID techniques. There is 122,865 square feet of
redeveloped area onsite and 75% of this area is 92,149 square feet or 2.12 acres. This area will be
treated with three onsite Rain Gardens aka Bioretention Ponds. The Bioretention Ponds will drain
to the 10' Type R Inlet at the SE corner of the site via a common 6" HPDE outfall pipe.
B. Directly Connected Impervious Area
The existing site will be redeveloped with a minimum increase in Directly Connected Impervious
Area. The increase in impervious area is 715 square feet, a 0.45% increase.
C. Development Criteria Reference and Constraints
The existing site has no stormwater management infrastructure, and drains undetained off --site.
The proposed stormwater management improvements meet Low Impact Development
requirements and will improve water quality and impact.
D. Hydrologic Criteria
' Action Civil Engineering LLC Page 6
I
Design rainfall values from "Table RA-8 — City of Forst Collins Rainfall Intensity -Duration -
Frequency Table for Use with the Rational Method" were used for the design rainfall. (Fort Collins
2016)
The Rational Method was used to determine peak runoff from sub -basins A, B, and C, for which
the methodology and tables as presented in the Urban Storm Drainage Criteria Manual were used
to determine Rational "C" coefficients, and time of concentrations. Calculations can be found in
' Appendix B of this report.
' E. Hydraulic Criteria
The UDFCD spreadsheet titled "UD-Detention" (Version 3.07, February 2017) was used to
' calculate both the required water quality capture volume for the three rain gardens and the
geometry of the rain gardens. In accordance with LID requirements, Water Quality will be
provided for 75% of the redeveloped area, 2.12 acres. The Water Quality Volume is calculated on
' a per basin basis. The calculations can be found in Appendix C of this report.
Autodesk Hydroflow Express was used to calculate the sizing of the rain garden underdrain. The
tcalculation can be found in Appendix C of this report.
' F. Floodplain Regulations Compliance
Fort Collins Jeep Dealership is located outside the 100-year floodplain, according to FEMA FIRM
' map panel 08069CI000F (Map Panel Not Printed). See "City of Fort Collins Floodplain Review
Checklist 50% Development Review Submittals" in Appendix A.
G. Modifications of Criteria
No modifications of the criteria are proposed.
' IV. DRAINAGE FACILITY DESIGN
' A. General Concept
The general. drainage concept is to capture 75% of the redeveloped impervious area and treat it by
LID techniques via rain gardens. Sub -basins A, B, and C have been designed to total this area.
Runoff will drain to these three rain gardens, where it will be treated. Treated water will discharge
via a 6" HPDE storm pipe to the existing storm sewer at West County Road 38 and South Mason
Street.
Sub -basins D, E, F, and G will not be detained or treated and will drain off -site.
No development will occur within Sub -basins H, I, and J as a part of this project.
Action Civil Engineering LLC Page 7
B. Specific Details
Surface runoff from sub -basins A, B, and C will sheet flow over pavement to concrete pans, then
collect in rain garden bioretention BMPs. The rain gardens are individually sized to the water
quality capture volume (WQCV) of their associated basins.
The three rain garden bioretention BMPs will be constructed with an impermeable liner on the
' bottom, a 4" slotted PVC under -drain pipe embedded in a 6" thick layer of CDOT Class B filter
material, and an 18" layer of filter media on top. The 4" under -drain will have 4" cleanouts to
provide maintenance access. A concrete outlet structure will have inlet(s) to receive discharge from
' the under -drain pipe(s) to receive discharge from the WQCV and an inlet grate to receive discharge
in excess of the WQCV. A 6" HDPE outlet pipe will discharge from the outlet structure to a
proposed 10' Type R Inlet at the intersection of West County Road 38 and South Mason Street.
The storm water will then discharge to the existing storm sewer via a proposed manhole
constructed on the existing storm sewer.
' In accordance with the LID techniques pertinent to the site, only the WQCV must be detained and
treated, and only for 75% of the total redeveloped area. Runoff in excess of the WQCV will pond
and discharge into the outlet structure inlet grate. If the ponding capacity is exceeded, the runoff
' discharge off -site to West County Road 38.
Sub -basins D, E, F, and G will not be detained or treated and will drain off -site. These areas do
' not require detention or treatment, as the LID requirement is satisfied by the rain garden
bioretention BMPs for sub -basins A, B, and C. Sub -basins D and G will discharge to West County
Road 38 via a curb cut. Sub -basins E and F will discharge to South Mason Street via the driveway
' at the northeast corner of the site.
' No development will occur within Sub -basins H, I, and J as a part of this project. The sub -basins
will continue to drain as per the existing conditions.
' V. CONCLUSIONS
' The stormwater management system for the site has been designed in compliance to the Fort
Collins Amendments to the Urban Storm Drainage Criteria Manual Volumes 1, 2, and 3. Low
Impact Development (LID) requirements were followed to determine BMP requirements.
The development of the site will increase the impervious area of the site from 158,473 square feet
to 159,188 square feet, an increase of 715 square feet. The stormwater management system will
capture and treat stormwater in accordance with the above criteria, and overall will improve the
water quality of stormwater and reduce the discharge off -site into the roadway.
VI. REFERENCES
City of Fort Collins, 2017. Mail Creek. Retrieved July 17, 2017, from
https://www. fcgov. com/utilities/what-we-do/stormwater/drainage-basins/mail-creek-
Action Civil Engineering LLC Page 8
' basin
2. Urban Drainage and Flood Control District (UDFCD). 2017. Drainage Criteria Manual,
Volumes 1, 2, & 3, Urban Drainage and Flood Control District.
3. City of Fort Collins, 2016. Fort Collins Amendments to the Urban Drinage and Flood
Control District Criteria Manual.
Action Civil Engineering LLC Page 9
Appendix A — Vicinity Map, Soils Map, Floodplain Checklist
I
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VICINITY MAP
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Natural Resources Web Soil Survey
Conservation Service National Cooperative Soil Survey
4P,70 4MM
40° 31'31'N
40'31'WN
490310
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1 /12/2017
Page 1 of 4
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Hydrologic Soil Group—Larimer County Area, Colorado
Hydrologic Soil Group
Hydrologic Soil Group— Summary by Map Unit — Larimer County Area, Colorado (CO644)
Map unit symbol
Map unit name
Rating
Acres in AOI
Percent of AOI
4
Altvan-Satanta loams, 3
to 9 percent slopes
B
0.2
5.0%
74
Nunn clay loam, 1 to 3
percent slopes
C
4.4
92.1 %
75
Nunn clay loam, 3 to 5
percent slopes
C
0.1
2.8%
Totals for Area of Interest
4.7
100.0%
Description .
Hydrologic soil groups are based on estimates of runoff potential. Soils are
assigned to one of four groups according to the rate of water infiltration when the
soils are not protected by vegetation, are thoroughly wet, and receive
precipitation from long -duration storms.
The soils in the United States are assigned to four groups (A, B, C, and D) and
three dual classes (A/D, B/D, and VD). The groups are defined as follows:
Group A. Soils having a high infiltration rate (low runoff potential) when
thoroughly wet. These consist mainly of deep, well drained to excessively
drained sands or gravelly sands. These soils have a high rate of water
transmission.
Group B. Soils having a moderate infiltration rate when thoroughly wet. These
consist chiefly of moderately deep or deep, moderately well drained or well
drained soils that have moderately fine texture to moderately coarse texture.
These soils have a moderate rate of water transmission.
Group C. Soils having a slow infiltration rate when thoroughly wet. These consist
chiefly of soils having a layer that impedes the downward movement of water or
soils of moderately fine texture or fine texture. These soils have a slow rate of
water transmission.
Group D. Soils having a very slow infiltration rate (high runoff potential) when
thoroughly wet. These consist chiefly of clays that have a high shrink -swell
potential, soils that have a high water table, soils that have a claypan or clay
layer at or near the surface, and soils that are shallow over nearly impervious
material. These soils have a very slow rate of water transmission.
If a soil is assigned to a dual hydrologic group (A/D, B/D, or C/D), the first letter is
for drained areas and the second is for. undrained areas. Only the soils that in
their natural condition are in group D are assigned to dual classes.
USDA Natural Resources Web Soil Survey 1/12/2017
211111111111111 Conservation Service National Cooperative Soil Survey Page 3 of 4
Hydrologic Soil Group—Larimer County Area, Colorado
Rating Options
Aggregation Method: Dominant Condition
Component Percent Cutoff.- None Specified
Tie -break Rule: Higher
USDA Natural Resources Web Soil Survey 1/12/2017
Conservation Service National Cooperative Soil Survey Page 4 of 4
City of Fort Collins Floodplain Review Checklist
50 % Development Review Submittals
Instructions: Complete this checklist by marking all boxes that have been adequately
completed. Put an "NA" next to any items that are not applicable to this particular
submittal. Any boxes that are left blank and do not have an "NA" marked next to them
are considered incomplete.
Date of Review: Reviewer's Name:
Plat Map
❑ The following required items are on the plat:
❑ 100-year floodplain boundary
❑ City
❑ FEMA
❑ Floodway boundary
❑ City
❑ FEMA
❑ The benchmark number and elevation of benchmark
❑ These items match the FIRM. (FEMA Basin)
❑ These items match the Master Plan. (City Basin)
❑ The benchmark number and elevation match with those published in the City of Fort
Collins benchmark system.
Site Plan
The following required items are on the site plan:
❑ 100-year floodplain boundary- FEMA and City
❑ 500-year floodplain boundary (if proposed structure is a "critical facility"
and a 500-year floodplain is mapped)
❑ Floodway boundary
❑ Erosion buffer zones
❑ Restriction related to use (i.e, critical facility or no residential use of lower
floor if floodproofed mixed -use structure)
Drainage and/or Grading Plan (or a separate Floodplain Sheet if it is too cluttered on
Drainage and Grading Plan)
The following required items are on the drainage and/or grading plan:
❑ 100-year floodplain boundary- FEMA and City
❑ 500-year floodplain boundary (if proposed structure is a "critical facility"
and a 500-year floodplain is mapped)
0 Floodway boundary
t❑ Erosion buffer zones
❑ Cross-section locations
' ❑ BFE lines
❑ Regulatory Flood Protection Elevation for individual lots or groups of lots
if structures are to be built in the floodplain.
❑ The floodplain and floodway boundaries are in the correct location and labeled
properly.
❑ The cross-section and BFE lines are in the correct location and labeled properly.
' ❑ Elevations are referred to the appropriate datum:
❑ FEMA basins — list in both NGVD 29 and NAVD 88
❑ City basins — list only in NGVD 29
' 0 Floodway regulations have been met.
❑ No fill in the floodway unless a hydraulic analysis shows "no -rise".
❑ No manufactured homes, except in an existing park, can be placed in the
floodway.
❑ No changing a nonconforming non-residential or mixed use structure to a
residential structure.
❑ Landscaping meets requirements for no encroachment in the floodway
without a hydraulic analysis to show "no -rise".
❑ No storage of materials or equipment.
❑ Critical facilities regulations have been met:
❑ 100 year— No life safety, emergency response, or hazardous material
critical facilities
' ❑ 500 year Poudre — No life safety or emergency response critical facilities
❑ Any items in the floodway that can float (Example: picnic tables, bike racks, etc.) are
noted as being anchored.
❑ Erosion Buffer Zone requirements have been met:
' ❑ Design of any allowed development minimizes disturbance to channel bed
and banks.
❑ No structures allowed.
❑ No additions to existing structures allowed.
❑ Any fencing is split -rail design and break -away, but cabled. Must be
oriented parallel to general flow direction.
' ❑ No detention or water quality ponds.
❑ No bike or pedestrian paths or trails except as required to cross streams or
waterways.
' 0 Road, bicycle and pedestrian bridges must span erosion buffer zone.
❑ No fill.
0 No outdoor storage of non-residential materials or equipment.
❑ No driveways or parking areas.
❑ No irrigated vegetation and non-native trees, grasses, or shrubs.
' ❑ No utilities except as necessary to cross streams or waterways.
❑ No grading or excavation except as required for permitted activities in
erosion buffer zone.
' ❑ No construction traffic except as required for permitted activities in
erosion buffer zone.
❑ Any construction in the erosion buffer zone shows that it will not impact
the channel stability. 1.
❑ Any necessary floodplain modeling has been submitted and approved. All modeling
' must follow the City's floodplain modeling guidelines.
' Special Poudre River Regulations
tions
0 Poudre River Floodway Regulations have been met.
' 0 No construction of new residential, non-residential or mixed -use
structures.
❑ No redevelopment of residential, non-residential or mixed -use structures.
' ❑ No additions to residential, non-residential or mixed -use structures.
❑ No fill unless hydraulic analysis shows "no -rise".
❑ Poudre River floodplain regulations have been met
❑ No construction of new residential or mixed -use structures
❑ No additions to residential structures
' ❑ No additions to mixed -use structures if there is an expansion in the
residential -use area of the structure.
❑ No floatable materials on non-residential sites
' Information Related to Structures in the Floodplain
' ❑ The regulatory flood protection elevation shown on the plans is at least 2 ft above the
BFE for the Poudre River and at least 18" above the BFE for new development and
redevelopment, 6" above the BFE for additions, substantial improvement and
accessory structures for all other floodplains.
❑ A note is on the plans that the lowest floor (including basement or crawl space) and
' HVAC will be required to be elevated above the regulatory flood protection
elevation. Non-residential structures can be floodproofed instead of elevated to the
regulatory flood protection elevation.
' ❑ A typical drawing detail is included for each foundation type proposed (slab -on -
grade, basement, crawl space) showing the elevation of the HVAC and lowest floor
' elevation (which includes bottom of the basement or crawl space) relative to the BFE.
tl: ,
❑ If garages are not going to be elevated to the regulatory flood protection elevation,
then a note is included stating the following requirements:
' ❑ There shall be 1 square inch of venting for every 1 square foot of enclosed
area.
❑ The bottom of the venting shall not be higher than 1 foot above grade.
' ❑ The venting shall be on at least two sides, preferably on upstream and
downstream sides. (Does not have to be divided equally).
0 For manufactured homes, a note is included stating that all submittal requirements on
separate sheet titled "Installation of a Mobile Home Located in a Floodplain:
' Submittal Requirements" shall be met.
' ❑ A note is on the plans stating that a floodplain use permit will be required for each
structure and each site construction element (detention ponds, bike paths, parking
lots, utilities, etc.) in the floodplain.
0 A note is on the plans stating that a FEMA elevation or floodproofing certificate will
be completed and approved before the CO is issued for any structures in the
floodplain. This is required even if property is only in a City floodplain.
Drainaee Report
❑ The site is described as being in the floodplain. Floodplain name and if the floodplain
' is a FEMA or City -designated is described. Any floodway or erosion buffer zones on
the site are described.
❑ The FEMA FIRM panel # and date and/or the Master Plan information is cited.
❑ A copy of the FIRM panel with the site location marked is included in the report.
' ❑ If a floodplain modeling report has been submitted, that report is referenced. The
reason for the floodplain modeling report is described.
' ❑ If a FEMA CLOMR or LOMR is going to be needed, the reason for the CLOMR or
LOMR is described.
' ❑ If a FEMA LOMR is required after construction, this is stated in the report.
❑ The location of the structures relative to the floodplain is described. If there is both a
FEMA and a City floodplain on the site, the location of the structures relative to both
is described.
1 0 The use of the structures is described. This is to determine if the structure is
residential, non-residential, or mixed -use. Also, structures in all 100- year and Poudre
' River 500-year floodplains cannot be used as a critical facility. (See Chapter 10 of
City Code for definitions.)
' ❑ The report describes how the development will be in compliance with the applicable
floodplain regulations (Chapter 10 of City Code). (Examples: elevation of lowest
floor above regulatory flood protection elevation, floodproofing, floodway
' regulations, erosion buffer zone regulations, no -rise, etc.)
❑ The type of foundation construction for the structures (i.e. slab -on -grade, crawl space,
' basement, etc.) is discussed in the report.
' ❑ The type of foundation matches with the details shown on the grading plan.
❑ The report states that the lowest floor (including basement or crawl space) and HVAC
' will be required to be elevated above the regulatory flood protection elevation. Non-
residential structures can be floodproofed instead of elevated to the regulatory flood
protection elevation.
❑ If garages are not going to be elevated to the regulatory flood protection elevation,
then a note is included stating the following requirements:
' ❑ There shall be 1 square inch of venting for every 1 square foot of enclosed
area.
❑ There bottom of the venting shall not be higher than 1 foot above grade.
' ❑ The venting shall be on at least two sides, preferably on upstream and
downstream sides. (Does not have to be divided equally).
❑ If a non-residential structure is to be floodproofed, then a note is included stating that
all requirements on separate sheet titled "Floodproofing Guidelines" shall be met.
(Floodproofing guidelines can be obtained at http://fcgov.com/stormwater/pdf/f`p-
floodproofing.pdf)
❑ For manufactured homes, a note is included stating that all submittal requirements on
' separate sheet titled "Installation of a Mobile Home Located in a Floodplain:
Submittal Requirements" shall be met. (Mobile Home guidelines can be obtained at
http://fcgov.com/stormwater/pdf/fp-mobilhome.pdf)
' ❑ The report states that a floodplain use permit will be required for each structure and
each site construction element (detention ponds, bike paths, parking lots, utilities,
' etc.) in the floodplain.
❑ A note is in the report stating that a FEMA elevation or floodproofing certificate will
be completed and approved before the CO is issued.
❑ In the compliance section, Chapter 10 of City Code is listed.
FEMA CLOMR Approval
❑ If a FEMA CLOW is required, the necessary modeling has been submitted and
approved by the City.
1 Additional Comments:
Updated 11/29/2007
Terms to Note
Lowest Floor Elevation — Elevation of the lowest floor of the lowest enclosed area
' (including bottom of basement or crawlspace). This is not the same as finished floor. The
lowest floor should be distinguished from finished floor on plans and reports.
' Regulatory Flood Protection Elevation — For all floodplains except the Poudre River, the
regulatory flood protection elevation is eighteen (18) inches above the base flood
elevation. For the Poudre River floodplain, the regulatory flood protection elevation is
twenty-four (24) inches above the base flood elevation. If there is both a FEMA and a
City BFE, the higher BFE should be used to determine the regulatory flood protection
elevation.
' Additional floodplain terminology is defined in Chapter 10 of City Code.
NOTE: Issues specific to individual sites may arise that result in additional
requirements. These will be discussed during initial meetings with the applicant.
Appendix B — Hydrologic Computations
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DETENTION BASIN STAGE -STORAGE TABLE BUILDER
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Project16.D1B Fon Collins 490P
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m
byr Runoff Volume (Pt a 1 1 ) •
30.yr Rulwff Volume (Pt a 1 A in) •
2 yr Runoff Volume, (P1 ° I in.) •
' S0-yr Runoff Volume (P1 - 2151n) °
100-yr Runoff Volume (P1 ° 2.BB In 1 °
S00.y1Runoevolume(P1a3.89m)=
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Pppronmele Syr Delenlwn Volume=
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Bann Lapm.to.WidM Ratio (R,ry.) a
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IWa of Basin Flog (A,00•) °
volume of Soon Fioor IV, op°) °
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Detention Basin Outlet Structure Design
uu-uetenxion, version a.Dy (hepruary zuiv)
Project: 16-018 Fort Collin. Jeep
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T 1 � Stage (k) Zone Volume (aok) Outlet Type
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User Input: Orifice at Underdrain Outlet Itypically used to drain WQCV in a Filtration BMP) calculated Parameters for Underdrain
Underdrain Orifice Invert Depth • 2.00 k (distance below the filtration media surface) Underdrain Orifice Area = 0.0 it,
Underdrain Orifice Diameter • 0.38 Inches Underdrain Orifice Centroid - 0.02 set
User Input: Orifice Pate with one or more odgces or Elliptical Slot Weir (typically used to drain WQCV and/or EURV In a sedimentation LIMP) Calculated Parameters for Plate
Invert of lowest Orifice - h(relative to basin bottom at Stage •Oit) WgOrifce Area per Row=M/A
Depth at top of Zone using Orifice Plate • h(relatWe to basin bottom at Stage• 0 k) Elliptical Half-Width=ar
Orifice Plea: Orifice Vertical Spacing = inches Elliptical Slot Centroid=et
Orifice Plate: Orifice Area per Row • Inches Elliptical Slot Area=
Urn Input: Stage and Total Are of Each Orifice
Stage of Ckr Can
Chiles Aras (eq.
Row 9 (optional) Row 10 (optional) Raw 11 (optional) Row 12 (optional) Row 13 (optional) Row 14 (optional) Row 15 o tlonel Row 16 o tlonel
Stage of Orifice Centrold (it
Orlfc, Area(K Inches
User Input: Vertical Orifiu Circular or Rectangular) Calculated Parameters for Vertical Orifice
Not Selected Not Selected Not Selected Not Selected
Invert of Vertical Orifice= k(relative to basin bottom at Stage• 0 k) Vertical Orifice Area= ft,
Depth at top of Zone using Vertical Orifice• h(relative to basin bottom at Stage •0it) Vertical Orifice Centroid• leer
Vertical Orifice Diameter - Inches
User Input: Overflow Weir (Drepboa) and Grate (Fat or Sloped) Calculated Parameters for Overflow Weir
Not SelectM Not SaacLed Not Selected I Not Selected
Overflow Weir Front Edge Height, He • It (reladve 1. basin bottom at Stage • 0 k) Height of Grate Upper Edge, H, = ifeet
Overflow Weir Front Edge Length - feet Over Flow Weir Slope Length = feet
Overflow Weir Slope= H:V(enter taro for flat grate) Grate Open Area /100-yr Orifice Area= should be 24
Horiz. Length of Weir Sides • feet Overflow Grate Open Area w/o Debris - it,
Overflow Grate Open Area %• %, grate open area/total area Overflow Grate Open Area w/Debris = k'
Debris Clogging %- %
' User Input: Outlet Pipe w/ Flow Restriction Plate (Circular Orifice, Restrictor Mate, or Rectangular Orifice) Calculated Parameters for Outlet Pipe w/ Now Restrictions Pate
Not Selected Not Saletted 1 Not Selected Not Selected
Depth to Invert of Outlet Pipe • I It (distance below bi aln bottom at Stage • 0 k) Outlet Orifice Area -1 k'
Circular Orifice Diameter •I Inches Outlet Orifice Centrold = feet
Half -Central Angle of Restrictor Plate on Plpe -1 N/A N/A radians
User Input Emergency Spillway (Rectangular ar Trapeaoaal) Calculated Parameters for Spi"
Spillway Invert Stage- It (relative to basin bottom at Stage -0k) Spillway Design Flow Depth -
Spillway Crest Length - feet Stage at Top of Freeboard =L�J e
Spillway End Slopes • H:V Basin Area at Top of Freeboard = acres
Freeboard above Max Water Surface • feet
Routed Hydrograph Resuks
Design Storm Return Period
One -Hour Rainfall Depth (In)
Calculated Runoff Volume (eve-k)
OPTIONAL Override Runoff Volume (acre-k)
Inflow Hydmgraph Volume (aci
Predevelopment Unit Peek Flow. A (olNecre)
Predevelopmem Peek 0 (cfe)
Peak Inflow 0 (cfa)
Peek Outfow Q icls)
Ratio Peak Outflow to PredavNopment 0 =
Structure Controlling Flow
Max Velocity through Grate i (Ipa) _
Max Velocity through Grate 2 (fps)
Time to Drain 97% of Inflow Volume (hours)
Time to Drain 99% or Inflow Volume (hours)
Mnilmum Pending Depth (it)
Area at Maximum Pending Depth (acres)
Maximum Volume Stored (eve-ft)
WQCV
EURV
2Year
5year
30 Year
25 Year
50 Year
100Year
500 Year
O.S3
1.07
0.99
1.10
1.40
1,99
2.is
2,86
3.89
O.DO6
0.020
0.016
0.019
0,024
0.035
0,038
D052
0.073
0.006
0.020
0.016
0.019
0.023
0.034
0,038
0.051
0.072
DOW
DOD
0.01
0,06
0.19
0,58
0.73
1,15
1.53
0A
0.0
00
0.0
0.0
0.1
0.2
0.3
0.4
0.1
0.2
0.2
0.2
0.3
04
0.5
0.6
0.8
0.0
0.0
0.0
0.0
0.0
0.0
a
010
0.0
N/A
N/A
N/A
0.5
0.2
0.1
0.0
D.0
0.0
Filtration Media
Filtration Media
Filtration Media
Filtration Media
Filtration Media
Flltratl0n Media
Filtration Media
Filtration Media
Filtration Media
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
12
36
30
35
43
63
70
93
130
12
37
30
36
44
65
71
95
133
D 67
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
0.01
0.01
0.01
0.01
0.01
001
0.01
0.01
0,01
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0.006
0.006
0.006
0.006
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0.6
0.5
0.4
0.3
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Detention Basin Outlet Structure Design
UD-Detentlan, Version 3.07IFebru2ry 2017)
IC
TIME lhrl
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minimum baund��
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Detention Basin Outlet Structure Design
Outflow Hydrograph Workbook Filename'.
Storm Inflow Hydrographs
UO-Detention, Version 3.07 (February 2017)
1^- anosl F,,,, l', nKy 1.
ra! • veloce ,ri
_
SOURCE
WORKBOOK
WORKBOOK
WORKBOOK
WORKBOOK
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WORKBOOK
WORKBOOK
WORKBOOK
WORKBOOK
Time Interval
TIME
WQN)ds]
EURV[efs]
2Year[ds)
SYear)ds)
10Year)ds]
25Year[cfsl
50Year[cfs)
100Year[ds)
500Year)ds]
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0.01
0.01
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0.03
0.01
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Detention Basin Outlet Structure Design
LID -Detention, Version 3.07 (February 3037)
Summary Stage-Area-Volume-Ohcharge geletlonahlpa
i_�rr. i�_.. .'1Ir a :: 11•e 1. i re i':e�. iM1f emsi.r lR.. ,li will., n i i.i:.�iir <.0
.h 1 .I ,jai ill W, Ti, rary2.n n mrle In ma luu s-A-V .I) Ilib IB i r lrt I i, it C co l it r ,r . II 1-:J I 1s1On uoinK
�'F.,
best Il Include the
stages of all grade slope
ISV and Flool
----_--(e.g.
Sheet gal
lrcl ude the Inverts of all
(e.g. vertical orifice,
grate, and spillway,
applicable).
------Also
-
-----_outlets
-
------overflow
-
-_----where
-
DETENTION BASIN STAGE -STORAGE TABLE BUILDER
LID-Detenlion, Version 2.07 (February 2017)
Praha'. eta Fort Collin Jean
,euw•I aural wwb
t0 Example Sum Configuration IRatantbn Payroll
Reginald Valid. C•kuingon
Saleclw BMP Type =
' 'Natemnad Moo -
Wammea Length
Wanrenad Sop. =
WeUnned Ngervbuaneee
' Pamaeelar HyErobgkS 11Gmup A=
Note n" Hydroaeph:W Group S
Panwaegt Rydrebgrc Sal Group• CID
Oorred WOCV Gram Tim
LO for 1-hr Rainfall OWN -
Water OIAaIIy, Chain volurre (WOCV) ii
' Exeb Gal Runoff VaWm(EGRvI•
2yr Runoff Volum (Pt • 00In.)
Syr Runoff Valuate (Pt • 1.1 In
10.yr Runoff Volume P1 • 14 In
]Syr Runoff volume IP1 • 1 N in
' 60W Rawff Va. IP1 • 215 to
1 My, Runaff Velum (P1 -2.88 m.)
500.yr Runoff voum (P1 • s.BT m.)
Aooronraae 2-y, Detealon Volume
fgproMrmle 5-yr Ghanaian Vol.. -
' Appronml610yr Deaenbn Volume•
AVpM`dm a 25-yr Deaen 10 Volume
Aodronrmaa 50-y1 Oaenhon Volum
Appra4rmla IM" Gawuon'Nu"
Sdrga-Stor•ge Calcuhtion
Zone l volume mccC •
Om
cre-fear
Salwl Zane 2 Storage voum (Opuonel) •
re lba
Select Zone 3 Store, Volume(Gphona(=
redeol
To,el Onanllon Baan V01.1-
o,ogg
(µ
Intuil Surrh.,. VOIum (ISVI •
WA
Initial Sur ,. Dapm(ISO)-
WA
Tam AvNaele Nuirlan Dolan (H_.) •
.
Capp of Txkle Channel (H:_( •
WA
Sbpe of Tn Ii. Ch." lS.cl •
WA
Sopo of Man Beam Saw IS,,,.,I `
uea
v
Soon 1-8,1n.w.Wiah Ratio R�„ -
uwr
I1111m Sumner0e Ana, (A)rl•
land
Surcharge Va1um Length 0.nl.
U.
Sumoge Volume WMm May)`
.1
Dwln of Sour Floor (Khoo.) `
Vbr
Lenptn or Begin Floa("u—).
W.am or Bean Floor full
A93 pl Spam Floo,(Anpya)`
V6er
.urm or Bwm Floor (V...)•
r
n-3
Depth of Man Born (Hain)
Length of Maln Swln (Lr„•l `
user
Wu1m a Mein Sean Mu.nd •
ubr
Are• a Meat Born (Aw•)•
uwr
VdVrm pl Mom Begin (VVarJ•
ub1
n�
Caalmad Total Boom Vaum (Val„) •
uW
rwI
Onuunm ulna Ova de
u Pr —,rill un
Goo nchb
110 nCMe
100 naMa
1 N raw
216 h,ma
286 naMh
387 non.
Total attention volume
It lob than 100-yotr
yalume
BVYannan Pond 6.dem. Spain 1lIG'2011, a 69 PM
DETENTION BASIN STAGE -STORAGE TABLE BUILDER
UD-Detentbn, Vom; n 3 07 (February 2017)
t
pI
p,00
' OA20
' OA25
' S 0.010
0:009
0.000
0.00
1
' BianlanLOn Poll B.tlsm, Deem
Op 1W
slwlal
—2erylelal—Amotlriel ax 1e0.a,l
pu
2m
sure 0el
eraa lames—eolumeac-III
L50
2F
300
200
Zap
I
200
0.020
Dma
2.00
1120r2017, 4'43 P
Detention Basin Outlet Structure Design
UD-Detention, Version 3.07 (February 20171
Project: I&OIS Fort Collins
Brain ID: Bloretentlon Pond
- �Zp1EeNE e
r a
stage (k) Zone Volume(aak) Outlet type
y=Iawwl ww Zonel(WQCV) 0.98 1 00(T9 I Filtration Media
rroresx Zone i
zuE t un z/ owncE
rraa.xs.n-- awrxrs 2one3
Example Zone Configuration (Retention Pond)
0009 oral
User Input: Orifice at Underdrain Outlet Itypkally used to draln WQCV In a FlNradom BMP)
Underdrain Onfice Invert Depth= i.00 it(distance below the filtration media surface)
Underdraln Ortflce Diameter= 0.46 inches
User Input: Office Plate with one or more orfikes
Invert of Lowest Orifice
Depth at top of Zone using Orifice Plate
Drdke Plate: Orifice Vertical Spacing
OHfice Plate: Orifice Area per Row
User Input: SLags end Total Am of Each Orifice
Stage of Orifice Cenbdd (ft
Oritics Area fact. Inches
Slope of Orifice Centroid if
Orifice Area(w inches
Invert of Vertical Orifice
Depth at top of Zone using Vertical Orifice
Vertical Orifice Diameter
(relative to basin bottom at Stage = 0 ft)
(relative to basin bottom at Stage = 0 ft)
Fr-1-1 en hinh-n
Calculated Parameters Inv Underdrain
Underdrain Orifice Area= 00 ft2
Underdrain Orifice Centroid= 0.02 feet
W Q Orifice Area per Row
Elliptical HalfWidth
Elliptical Slot Centroid
Elliptical Slot Area
Rowt tonal) Row2 tonal Row3 tlonal Row4 tional RowS(0DU0ralJ R0.6iciplonall R0w7 'onal Row8 Oonal
Row 9 tonal Row 10 a tional Row 11(optimal) Row 12 onal Row 13 (ciptioral Row 14 joptorall Row 15 'sxW Row 16 'oriel
or Rectangular) Calculated Parameters for Vertical Orifice
Nol Sakcted Not SelectedI Not Selected Not Selected
fit (relative to basin bottom at Stage =oft) Vertical Orifice Area= I It
it(relative to basin bottom at Stage =0fit Vertical Orifice Centroid =1 feet
' User Input: Overflow Weir(Dropbox) and Is (Flat or Sloped) Calculat
Not Selected Not Selected
Overflow Weir Front Edge Height, Ho= h(relative to bosun bottom at smile =0 h) Height of Grate Upper Edge, Hr
Overflow Weir Front Edge Length = feet Over Flow Weir Slope Length
' Overflow Weir Slope= HM(enter zero for gat grate) Grate Open Area /100-yr Orifice Area
Mainz. Length of Weir Sides = feet Overflow Grate Open Area w/o Debris
Overflow Grate Open Area%= %, grate open area/total area Overflow Grate Open Area w/Debris
Debris Clogging%= %
' User Input: Outlat Pipe w/ Flow Restriction Plate(Orcufar Orifice, Restrlctor Plate, or Rectangular Orifice) Calculated Parameters for Outlet Pi w/ Flow Restriction Plate
Not Seleeted Not Selected Not Selected Not Sele!jf:
Depth to Invert of Outlet Pipe = h (distance below basin bottom at Stage = 0 k) Outlet Orifice Area =
Circular Orifice Diameter = inches Outlet Orifice Centroid = Half -Central Angle of Restrictor Plate on Pipe= N/A N/A ctions
User Input: Emergency SpMway (Rectangular or Trapezoidal) Calculated Parameters tar SplYwey,
SpillwayInvertstagn fret to basin bottom at Stage .0 ft) SpillwayDesignFlow Depth=�ean
Spillway [rest Length= feet Stage at Top of Freeboard= eet
Spillway End Slopes = H:V Basin Area at Top of Freeboardacres
Freeboard above Max Water Surface - feet
Routed Hydrograph Beau
Design Storm Return Period =
One -Hour Rainfall Depot (in) _
Calculated Runoff Volume (aae-fl) _
OPTIONAL Override Ruroff Volxne face-fl) _
Inflow HydrDgmph Volume (aae-ft)
Pi edeveiopment Unit Peak Flow. p (cfaraere) _
Pnedmelognent Peak Q lots) =
Peak Inflow Olds) =
Peek Outflow 0 (c4) _
Ratio Peak Outflow to Predevelopmem 0 =
Structure Controlling Flow -
Max Voki through Grate 1 (fps) =
Max Velocity through Grate 2 (fps) _
Time to Drain 97%of Inflow Volume froure) =
Time to Drain 99%of Inflow Volume (houa) =
Maximum Pointing Depth (A) _
Area M Maximum Pondi g Depth (aces) _
Maximum Volume Stored (ace-ft) =
bez4
WQCV
EURV
2Year
5Year
10 Year
25 Year
50 Year
IOOYear
500 Year
0.53
1.07
0.99
1.10
1.40
1.99
2.15
2.86
3.87
0.009
0.029
0.024
0.028
0.036
0.053
0.058
0.078
0.108
O.ODS
0.029
0.023
0.027
0.035
0.052
0.057
0.078
0,108
0.00
0.00
0.01
0,07
0.21
063
0.80
1.24
1.96
0.0
0.0
0.0
0.0
0.1
0.2
D3
0.4
0.6
0.1
0.4
0.3
0.3
0.5
OJ
0.7
1'0
1.4
0.0
00
00
0.0
0.0
0.0
UO
0.0
00
N/A
NIA
N/A
0.4
0.1
0.0
0.0
0.0
0.0
Filtration Media
Filtration Media
FlRratlon Media
Filtration Media
Filtration Media
Filtration Media
Filtration Media
Filtration Media
Filtration Media
N/A
N/A
N/A
N/A
N/A
N/A
NIA
N/A
N/A
NA
NA
NA
NA
NA
N/A
NA
NA
NA
12
37
30
34
45
65
71
96
133
12
37
31
35
46
67
72
98
136
0.73
100
1.00
1.00
1.0o
100
1.00
1.00
1.00
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0007
0.009
0009
0.009
O.OD9
0-009
0.009
0.OD9
0.009
t.0
3.1
1
0.8
OS
0.4
0.1
0
0.1
1.1
1
0.8
Detention Basin Outlet Structure Design
uu-ueren[mn, version s.ur [re0ruary zulq
smrx a
E
I 0
TIME Ihrl
OMIN TIME Ihrl
aso
:� UserArcalMll
s00
_
—IMerpdateeAm lh^ll
_ --
..a_wmm.rrara.lh^ll
-
350
-
—Valumc [h"3l
•• 0 •• Summary Volume lh13l
301)
—Duffi. l3lsl
--0-- Summery Outflow Itfsl
T
e
150
Ei
300
SaC
150
3
100
50
—
0
0.00
0.10 0,x0 0.50
VONDING OEM Ihl
B-A-V-D Chart Aela Ovaul0a x-axis Lett Y-Axis RI hl V-Aais
minimum bou
lMmum
maxiCountf
l0 too
i� 0.03
0.01
0.01
0.00
0.00
0.00
0,R
Detention Basin Outlet Structure Design
Storm Inflow Hydrographs UD-Detention, Version 1.07 (Febmary 2017)
- - .,'ated InOnx hydmomphs horn Ws w t-.0 WN Inflow h..
SOURCE WORKBOOK WORKe00K WORKBOOK WORKBOOK WORKBOOK WORKBOOK WORKBOOK WORKBOOK WORKBOOK
Time InIm al TIME WQCV [dsI EURV(cfs] 2Year[cfsl SYear[cfs] 10Year(ds] 2SYe3r[cfsl 5OYear(ch] 100Year(ds] S00Yearids
8.78 min 0:00:00 0m o00 000 o00 0.00 0.00 ow 000 000
Hyd,oWeph
0:13:34
0.m
ow000
CA
Coo
0.00
0.00
2A0
0
constard
0:20:20
0.01
0.02
0.03
0.02
0.02
0.03
0.03
0.05
0.0000
0.737
0:2707
0.02
1 0.05
ON
1 004
006
1 ON
O.W
I0.12
0.16
Detention Basin Outlet Structure Design
UD-Detention, Version 3.07 (February 2017)
summary, StagMrea-volumtDlscharge Relationships
'File user can create a summary S-A-V D by nnlering the dI stage increrneols and the rernainGar of the table WII populate automatically
The user shoulri lyaphlcally comoara the summary S-A-V-0 table to the full S A V D table In the chars In confirm II caidure, All Mev transillon points
®®®®®®®
best results, Includethe
of all grade slope
changes (e.g. 5V and Floor)
------stages
-
-------
from the S-A-V table on
Sheet 'Basin'.
Also include the inwers; of all
outlets (e.g. wil orifice,
grate, and spillway,
where applicable).
------erfl..
-
-------
-IIIIIIIII_-----
—IIIIIIIIIIIIIIIIIIII♦IIIIIIIIIIIIIIIIII■IIIIIIIIIIIIIIIIII■IIII—IIIIIIIIIIIIIIIIIIII,—
—IIIIIIIIIIIIIIIIII■1111111111111111111111III----
—IIIIIIIIIIIIIIIIIIIII,IIIIIIIIIIIIIIIIIIIIII,IIIIIIIIIIIIIIIIIIII,
IIIIIIIIIIIIIIIIIII♦1111111111111111111111111111111111111111111111
—IIIIIIIIIIIIIIIIII■
IIIIIIIIIIIIIIIIIII♦IIII—IIIIIIIIIIIIIIIIII♦IIIIIIIIIIIIIIIIII♦IIIIIIIIIIIIIIIIIIII♦
---I---IIIIIIIIIIIIIIIIIIII♦
----I—I—IIIIIIIII-
---IIIIIII—I--III-
---IIII----
--_IIIII--IIIIIIIIIIIIII--
---IIIIIIIIIIIIIIIIII■
_—IIIIIIIIIIIIIIIIIIII♦
--IIIIII---IIIIIIIIIIIIIIIIII■IIIIIIIIIIIIIIIIIIII♦
---II—IIIIIIIIIIIIIIIIII♦--
--IIIIIIIIIIIIIIIIII♦—IIIIIIIIIIIIIIIIII♦--
-IIIIIIIIIIIIIIIIII♦—IIIIIIIIIIII_IIIIIIIIIIIIIIII.—IIIIIIIIIIIIIIIIIIII■
—IIIIIIIIIIIIIIIIII■IIIIIIIIIIIIIIIIIII♦IIIIIIIIIIIIIIIIIII■IIIIIIIIIIIIIIIIII♦
II—IIIIIIIIIIIIIIIIIIII■
—
IIIIIIIIIIIIIIIIIIIII,111111111111111111111111111111111111111111♦
IIIIIIIIIIIIIIIIII■
IIIIIIIIIIIIIIIIIIIIII,
IIIIIIIIIIIIIIIIIIII■
---IIIIIIIIIIIIIIIIII♦---
—
IIIIIIIIIIIIIIIIII■
IIIIIIIIIIIIIIIIII■
1111111111111111111111111111111111111111■
IIIIIIIIIIIIIIIIIIIIII,
IIIIIIIIIIIIIIIIIIII■
—IIIIIIIIIIIIIIIIII■
IIIIIIIIIIIIIIIIII■1111111111111111111111111111111111111111■II—IIIIIIIIIIIIIIIIIIII■
--_--IIIIIIIIIIIIII_—
----IIIIIIIIIIIIIIIIII♦II--
DETENTION BASIN STAGE -STORAGE TABLE BUILDER
UU-Detention, Verabn 3.D7 (February 2017)
Protect'. 1e-0'IB Fon Colllne Jeoo
Basin ID'. Blwabntlon Pone C
w�wTT �
1 Ta�a
an
ro•/ w a
Elu mpla lone CondlBumtlon (Retention Pondl
Required Vol. Calculation
B uvdd BMP
NateSMU
Welenneo slope•
o0J5
n
Warman. 4r nna m,iii •
w wov
It
demand" Hydro"Id Sou Group A•
0.0%
enl
Pardenls,s HyCmbpK Soil Gmup B -
0 0%
roam
Pe damage Horologe Sall Grwpa CID =
100,0%
mnt
Came WDCV Own Time•
12.0
ours
Loodmn for 1 m Remlen Dennis • Era
weer, OupMy Cwlun Volume MCCV)•
0.042
Cafem
Eve Urean Runoff Valume(EURVI-
0w
wafeel
2yr Rulloll Volum(P1. 0 W in).
D113
one fee
099
Imore.
Syr Runde Volume (PI e 1 1 m) .
01M
oreTeel
1 10
none.
1Dyr Runde Volume (P1 e l a in ) •
0171
—hall
1 ao
hms
2Syr Ruroe Volume(PI =I 99 in I-
0MI
age ful
199
none.
50-yr Pump VolurM(PI .215 in 1=
0.274
Cm feet
215
none.
100.yr Ruroe VOlume(PI -2.Bi11n 1-
0323
on. feel
2e5
none.
5 yr Rurofl Vch.re(PI -De9m.1-
0519
afeei
'none.
OpprOnrrole 2.yr Deletion Vaimm
0.106
ae.leer
Mmittrnle 6-r Common Volone,
olzs
deals(
rppmamaer 10"Detention Volume
0150
c-fam
aapmernme 2syr Deirmunn Velum •
0209
dra.lP.1
PDpIOnTBIe 5Dyr Delenuon Volume •
0IM
R.leel
Anon... 10Dyr Detention Vourro.
ax51
.(eel
BteBa-Btoropa Calculation
Zone 1 Vaunt, n aW
Select Iona 2 Storage Voume (dentate)
Select Zone 3 storage Volume (optional) -
Total Ownlmn Bum Volume =
New surcharge wourns I IBV) -
meial SurUBr9• Depth (IBD) -
Total ArellBdN Deernndn Depth (K..,) -
Depth of Thotie Crummil (Hk) -
Sidpe of TrKele Chann t (Sh)-
Sbpe. elf Mein Ben $We. (s vr)
Basin LenOm.to-wiam Recto (R,w) e
Kmat Sundmil Nee (qw)
Summarpe wuma Lane", (L,a)
suiwroe volume Width (w t)
Depth 0f Henm Fbor Mr...)
Lmdth .I Seem Floor(Lnoo.)
WHN of B•.in Fmr (WI—)
Nee of Ben Flow (N,o.J
Volume or Iben Fbor (V.mo.)
Noah of Mein Bean (HeuJ
Length of Main Bum(Luux)
Worm of Main BNIn W _)
Mee M Met Bad. (A.,.,J
voiuhva of Man Bwln (Vey.)
Calculated Total Boen Volurne (V„„„,)
B
Tol.l e.bnildn volume
i. I... than IDpyaer
volume
�e2.SiSl.1R•i��tll�
�li���
��
•.
BIwN.nlmn Pond C tam, Bean 11i6,2011. 4 40 PM
o.m
DETENTION BASIN STAGE -STORAGE TABLE BUILDER
UD.DetenWn. Vami n 3.07 (Fsb ary 2017)
snpinl
—..Eh I An. (Iftl
1.ao
SY (ft.)
A.11.1..1 —V.1um.l.1-nl
iw
00
wo
300
0
z.oa
o.ws
Y
O.03o
0.015 l
— o.wo
1.00
meNnnon Pond c 4.m Bello 11/B2017, d 40 PM
1
Detention Basin Outlet Structure Design
Project: 16418 Fort Collins Jeep
Baaln to: gioretendon Pond C
Stage (k) Zone Volume(ac-k) Outlet Type
area, Zone Zone I1WQCvj 0.96 0.042 Filtration Media
Zone 2
Nf Wpl (MrKF
IPAruMM dwicaa ione3
xw_ Example Zone Configuration (Retention Pond) 0042 tribal
User Input: Orifice at Underdraln Outlet (typically used to drain WQCV In a Filtration SNIP) Calculated Parameters for Underdrain
Underdrain Orifice Invert Depth= 2.00 k(distance below the filtration media surface) Undertlram Orifice Area= 0.0
Underdrain Orifice Diameter = 1.02 inches Underdrain Orlflce Commit! = 0.04 feet
User Input: Orifice Plate with one or more orMkes or Elliptical Slot Weir (typically used to drat. WQCV and/or EUF
Invert of Lowest Orifice • k(reiaClve to basin bottom at Stage =Olt)
Depth at top of Zone using Orifice Plate = If,, tive to basin bottom at Stage =0k)
Orifice Plate: Orifice Vertica l Spacing = inches
Orifice Plate'. Orifice Area per Row = inches
User Input Stage and Tool Area of Each Ortflce
Stage of Orifice Centrold (h;
Orifice Ana (q. Incheal
Stage of Odgcs Centrold (it)
Odgce Ares Haar inch")
User Input: Vertical Drifts(CIr
Invert of Vertical Orifice -
Depth at top of Zone using Vertical Orifice -
Vertlal Orifice Diameter -
(relative to basin bottom at Stage - 0 fill
(relative to basin bottom at Stage = 0 k)
Mete
VJQ Orifice Area per Row
Elliptical Half -Width
Elllimcel Slat Centrold
Elliptical Slot Area
Calculated Parameters for Vertical Or la
Not Selected Not Selected
Vertical Orifice Area - k'
Vertical Orifice Centrold -I feet
User Input: Overflow Weir (Dropboxl and Grate (Flat or Sloped) Calculated Parameters for Overflow Weir
Not Selected Not Selected Not Selected I Not Selected
Overflow Weir Front Edge Height, He- It(relative to basin bottom at Stage =Olt) Height of Grate Upper Edge, H,= feet
Overflow Welr Front Edge Length - feet Over Flow Weir Slope Length = feet
Overflow Weir Slope+ H:V(enter zero for flat grate) Grate Open Area /100-yr Orifice Area= should be a
Hertz. Length of Weir Sides - feet Overflow Grate Open Area w/o Debris - ft I
Overflow Grate Open Area %_ %, grate open areattotal area Overflow Grate Open Area w/Dews- k°
Debris Clogging %+ %
User Input: Outlet Pipe w/ Flaw Rosh etbn Mate (Circular Odfia. Restdctor Plate, or Rectangular Orifice) Calculated Parameters for Outlet Pipe w/ Flow Restriction Mate
Not Selected Not Selected Not Selected Not Sesich d
Depth to Invert af0utlet Pipe• IT (distance below basin bottom at Stage• 0 k) Outlet Orifice Area= kz
Circular Orlflce Diameter • Inches Outlet Orifice Centrold =I I feet
Half -Central Angle of Restrlctor Plate on Pipe -1 N/A I N/A radians
User Input: Emergency Spillway (Rectangular or Trapazoldall Calculated Parameters for Spllhvay
Spillway Invert Stage= 1t Initiative to basin bottom at Stage-0 k) Spillway Design Flow Depth= feet
Spillway Crest Length= feet Stage at Top of Freeboard=feet
Spillway End Slopes= H:V Basin Area at Top of Freeboard= acres
Freeboard above Max Water Surface= feet
Routed HVdrograph Results
Design Storm Return Period
One -Hour Rainfall Depth (In)
Calculated Runoff Volume (aue-fa
OPTIONAL Overrate Runoff Volume (Kre-ra
Inflow Hydngraph Volume (sortrh)
Predevelopment Unit Peak Flow, q (c(slacre) _
Pradevelopmenl Peak O (do)
Peek Inflow 0 (do)
Peak Outflow O (cfs)
Rollo Peak Outflow to Pradevelopment O
Structure Controlling Flaw
Max Velocity through Orate 1 (fps)
Max Velocity through Orate 2 (fps)
Time to Drain 97%of Inflow Volume (hours)
Tim, to Drain 99%of In0ow Volume (hours) _
Maximum Pending Depth (k)+
Area at Maximum POIMIno Depth (acres) _
Maximum Volume Stored (acrehi
WOCV
EURV
2Year
5Year
30 Year
25 Year
50 Year
100 Year
500 Year
0.53
1.07
0.99
1.10
t.40
1.99
2.15
2.96
3.89
0.042
0.140
0.113
0.133
0.171
0.251
0, 274
0.373
0.519
0.042
0.139
0.113
0.132
0,170
0.250
0.273
0.372
0.518
0.00
0.00
0.01
0,07
0.20
0.60
076
1.19
1.89
0.0
O.0
0.0
0.1
0.3
0.9
1.2
1.9
3.0
0.5
L7
1.4
1.6
2.0
3.0
3.2
4.4
6.1
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
OD
NIA
N/A
N/A
0.5
0.1
0.0
0.0
0.0
0.0
Filtration Media
Filtration Media
Filtration Media
Filtration Media
Filtration Media
Filtration Media
Filtration Media
Filtration Media
Filtration Media
NA
NA
NA
NA
NA
NA
NA
NA
N/A
N/A
N/A
NIA
N/A
N/A
N/A
N/A
N/A
N/A
12
36
30
34
44
64
69
94
130
II
37
30
35
45
65
71
96
133
O.75
1.00
I DO
1.00
1,00
1.00
1.00
1. GO
1.00
0.04
0.04
0.04
0.04
0.04
0.04
0,04
0.04
0.04
0.033
0.044
1044
DA44
0.044
a.044
0,0"
0.044
0.044
SOem IM
SWI11 W\
IOg111M
6
5
_/
Y
3
l
0
0.]
1
0.6
e
10.6
0.4
0.2
0
0.1
I,s00
0 Veer ArealftA]1
— ImelMiatetl Area Ift"11
1♦ 5ummary Area Ift•S)
2,000
—V.I..itHl
••►• Summary Vdume M"3)
—oudimi Id')
aa.. Summary OuftO [ns]
m 1,500
1,000
—
C_
ig
sa0
Detention Basin Outlet Structure Design
uu-uerennon, version n.ui tre0ruary mlq
EI
1 10
TIME Ihr)
DIIAIN TIME IhrI
10
0.00 0.10 040 0.60 0.80 1.00
MNDING DEPIN Ift)
S-A-V-D Chan Axis ovaMOa X-ads Left Y-Axis RI ht V-Axis
minimum b ntl
maximum Wuntl
100
0.05
005
0.0a
0.04
0.03 _
0.03
001
0,02
0,01
0.01
0.00
1,20
' Detention Basin Outlet Structure Design
Storm Inflow XydnWaphs
UD-Detention,Vemion3.07[Febr Vary
-h5 '..ser can cremde the calculated -i nll.]w hydrn9ra0hs fmm this wvY
16velopBn in a 6eGar..l-
SOURCE
WORKBOOK
WORKBOOK
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WORKBOOK
WORKBOOK
WORKBOOK
WORKBOOK
WORKBOOK
WORKBOOK
Tme lntwval
TIME
WOCV]<fs]
EURV]ds)
2Year[ds]
SYear[ds]
10Year[ds]
25 Year[ds]
SOYear[ds]
1MYear[ds)
500Year[cfsl
7.07 min
O:W:00
0.00
O.W
O.W
Um
O.W
O.W
O.W
O.W
0.W
Hydrogrdph
0:16:08
0.W
O.W
0.W
CM
OW
0.00
0.W
0.00
0.W
ConslaM
0:21'13
0.02
0.08
0.06
0.0]
0A9
0.13
0,15
0.20
0.2]
0.707
0'.28:17
0.06
020
0.16
8.19
o25
0.36
0.39
0.53
OJ3
I Detention Basin Outlet Structure Design
IJD�Detention, Version 3.07 (February 2017)
Summary Stage -Area -Volume -Discharge Relationships
l :gym oi ta,cr. ewe an„r aid b-A-V D b, et lemy tlo- de,eJ sl. rr s er er le ono the remainder of the table will poollot, ur t" ."'A'
The r.l l rran Ilr mna e .he. S-A-V-5 lahlr. In the lull S-A V-D Inblc -r the chart In -nl t m I couture, all k.v tramton nninh,
For best results, include the
stages of all grade slope
(e.g. ISV ad Floor)
from the S-A-V table on
------clao,es
-
-------
include the irverts of all
vertical orifice,
!overflow grate, and spillway,
here applicable).
-------Mso
---_---'(e.g.
---_--0'
-
I ,
I
III /
II I
I II
it l
II II
I
I I
I I
II I.
mu
L CW BEND
ACREIFASE bTRUCnXRE
V Ih 1
Ti
i
WQBIORETENTION BASIN B
VOLUME REQUIRED = 0.009 AC -FT
VOLUME PROVIDED = 0.009 AC -FT
I
I I n1
1 / n{
I�r'I I/ I n;
II IS
I I I I�9
I I 1 I Vq PEIEISE 3IRUCNiF
s
II E
&III � / % 1P-e•NDIP
I RARFD1OnUtlll // X41'
i ill I r J
III I
II II,
I I I I em•BEHn
I I I 10
I l\/
I /
1I I I t
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Runoff Analysis Date Table
Best) ID
C2
C100
02 (CIS)
0100 (Ma)
A
0.87
0.95
&W
2.02
B
0.B3
0.0
0.76
2.94
C
0.80
0.89
3.33
12.96
i
r -1
NNP - �
DRAINAGE LEGEND
M M M M
PROPOSED BASIN BOUNDARY LINE
'S«a' -
EX. MAJOR CONTOUR
-
EX. MINORCONTOUR
�Saa—
PR. MAJOR CONTOUR
PL MINOR CONTOUR
ummrw=o
U. STORM
P . STORM
PROPOSED CONCRETE
BASIN
NAME
II
.SOT
9
'Lyi
1Wyl
3WC VALUE
BASIN LABEL
ppYC VALUE
---I 7
A
F
\, t 0.42 WA
)PIPE
I I a I O O I ��
t I1 s WQBIORETENTION IN A ' r
I VOLUME REQUIRED = 0.006 AC -FT I I I
VOLUME PROVIDED = 0.006 AC -FT I
_ I 1
■ III. III. �
C I _ LOT 1
1' P 1.72 :89 L
B y e I 1 a
0.331.1 1 \\ \I 1 O I I I
0,56
WA
WEE-, t�
\
\ I
I• `ooBaioTTEnRPE \ ' _. _L =' J
\ AB
---c -L- 1. /
sI
I I r , WOIBIORETENTION BASIN C -
l an`1M VOLUME REQUIRED = 0.042 AC -FT /
I j VOLUMEPROVIDED=0.042 AC -FT /I
I I vamc I aLOTTED PPE I T/ ♦ wonEiEAse s,nucTulE /�1
�L ,
311E-C XI
■ IIII
� •r
WEST HARMONY ROAD
BASN ACREAGE
Qi DESIGN POINT
�11 If
it I
II II
II it
II II
II I,
II II
II
II I
II !I
$ II I
\ II II
II II ----
II it
11 l
N
I
I
I
BENCHMARK:
iii BENCHIAINKPRWECT : .MANORS
BENCHMARK IM&N. AN ALLOY CAP LOCATED ON THE RIM OF AN ELECTRIC
S I I MANHOLE ON THE NORTH SIDE OF HARMONY ROAD. APPROXIMATELY SV
\ I EASTOFTHESOUTH 1NCCRNERO1`SECT1CN35.
\ ELEVATION =5 79
11 I BENCHMARKIM"l, APPROXIMATELYIn SWTHOFHORSETOOTHROAD,
WESTOF COLLEGE AVENUE AT THE ENTRANCE OF BMNES AND NOBLE
BOOKSTORE, IN THE NORTHEAST CORNER OF THEIR PARKING LOT, ONA
CONCRETE CURB.
I ELEVATION =3D35.T8
PLEASE NOTE: THIS PUN SET IS USING MAVENS) FOR AVERTICAL DATUM.
IOP08EDAMLOAFLNNT SURROUNDING DEVELOPMENTS HAVE USED NGVD39 UMMUSTED FOR
SFUT TOR STORM MANHOLE THEIRVERTCALDATUMS.
I IF NOVI)n UNADJUSTED DATUM IS RECURRED FOR ANY PURPoSE, THE
IF -CRAPE r_. .FIXLOWING EQUATION SHOULD BE USED:
PROPoSEU I6 TYPE R NI£T NGV039 UNADJUSTED=NXV -3.19
IPNOPWEDAE CCIA
49MU TTOPSTORM4
MN11O£CONNECT AMP
OUTIETTO E ISTING
STORM SEVER
—EMsnec sroRM SEWER 1Le
below.
CITY OF FORT COLLINS, COLORADO
UTILITY PLAN APPROVAL
AFFRONTED.
cm ENONEEa �Tf
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