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HomeMy WebLinkAboutTHE LANDING AT LEMAY MULTIFAMILY AND MIXED-USE - FDP230020 - SUBMITTAL DOCUMENTS - ROUND 6 - Drainage Related Document
1
FINAL
DRAINAGE REPORT
THE LANDING AT LEMAY
FORT COLLINS, CO
April 10, 2024
Owner: Thompson Thrift Residential
Planner: Ripley Design, Inc.
970.224.5828
Design Engineer: Avant Civil Group
970.286.7995
AVANTCIVILGROUP.COM
FORT COLLINS, CO 80525
2
April 10, 2024
City of Fort Collins
Stormwater Utility
700 Wood Street
Fort Collins, CO 80521
RE: FINAL DRAINAGE REPORT FOR THE LANDING AT LEMAY
Dear Staff:
Avant Civil Group is pleased to submit this Final Drainage Report for The Landing at Lemay for your review. This report
accompanies the FDP 05 submittal for the project.
This report has been prepared in accordance with the Fort Collins Stormwater Criteria Manual (FCSCM) and serves to
document the stormwater impacts associated with the proposed Landing at Lemay project. We understand that review
by the City of Fort Collins is to ensure general compliance with FCSCM drainage criteria.
If you should have any questions as you review this report, please feel free to contact us.
Sincerely,
AVANT CIVIL GROUP
Austin Snow, PE
Project Engineer
3
Engineer Certification:
“I hereby attest that this report for the Final drainage design of The Landing at Lemay was prepared by me, or under my
direct supervision, in accordance with the provisions of the FCSCM. I understand that the City of Fort Collins does not and
shall not assume liability for drainage facilities designed by others.”
Austin Snow, PE
State of Colorado License No. 53340
4/10/24
4
Table of Contents
General Location and Description .................................................................................................................................................................. 6
Location................................................................................................................................................................................................................ 6
Description of Property .................................................................................................................................................................................. 6
Existing Conditions ...................................................................................................................................................................................... 7
Drainage Basins ..................................................................................................................................................................................................... 7
Major Basin Description ................................................................................................................................................................................. 7
Sub-Basin Description .................................................................................................................................................................................... 8
Drainage Design Criteria .................................................................................................................................................................................... 8
Optional Provisions.......................................................................................................................................................................................... 8
Stormwater Management Strategy ........................................................................................................................................................... 8
Development Criteria Reference and Constraints ............................................................................................................................... 9
Hydrologic Design Criteria ........................................................................................................................................................................... 9
Hydraulic Design Criteria............................................................................................................................................................................... 9
Conformance with Water Quality Treatment Criteria ........................................................................................................................ 9
Conformance with Low Impact Development (LID) Requirements .............................................................................................. 9
Sizing of LID and WQ Facilities ................................................................................................................................................................. 10
Rain Gardens ............................................................................................................................................................................................... 10
Stormtech Chambers ................................................................................................................................................................................ 10
Water Quality .............................................................................................................................................................................................. 10
Drainage Facility Design .............................................................................................................................................................................. 10
General Proposed Concept(s) ............................................................................................................................................................... 10
Sub-Basin Descriptions ............................................................................................................................................................................ 11
Detention Details ............................................................................................................................................................................................ 12
Conclusions ........................................................................................................................................................................................................... 13
5
Compliance With Standards ....................................................................................................................................................................... 13
Drainage Concepts ........................................................................................................................................................................................ 13
References.............................................................................................................................................................................................................. 14
APPENDIX A – HYDROLOGIC CALCULATIONS ................................................................................................................................................. A
APPENDIX B – HYDRAULIC CALCULATIONS .................................................................................................................................................... B
APPENDIX C – LID AND WATER QUALITY ...................................................................................................................................................... C
APPENDIX D – USDA SOILS REPORT .............................................................................................................................................................. D
APPENDIX E – FEMA FIRMETTE ........................................................................................................................................................................ E
APPENDIX F – DRAINAGE EXHIBIT .................................................................................................................................................................... F
6
General Location and Description
Location
The Landing at Lemay project site is located in a tract of land located in the Northwest Quarter of Section
7, Township 7 North, Range 68 West of the 6th Principal Meridian, City of Fort Collins, County of Larimer,
State of Colorado.
Figure 1 - Site Location
The project site (see Figure 1) is bordered to the north by open space and E Vine Drive, to the east by
Cordova Road (proposed and future), to the south by The Cottages of Fort Collins, and to the west by South
Lemay Avenue. There is existing storm drainage infrastructure to the south that was constructed with the
Cottages of Fort Collins project.
Description of Property
The Landing at Lemay site is comprised of 27.38 acres – a portion of the parcel(s) to the north will remain
undeveloped while the multifamily development (~17.5 acres) is constructed. The site is currently comprised
of undeveloped open space. The project site resides in the City of Fort Collins Dry Creek Master Drainage
7
Basin. The detention requirements and release rates of the subject area were considered in the design of
the detention ponds for The Landing at Lemay and have been factored into the LID requirements, which are
described in further detail throughout this report.
The proposed development will consist of ten (10) multi-family residential buildings containing 336 units
with on-site and street parking, and a clubhouse. The proposed land use is multi-family, which is a permitted
land use for this area.
Exis ng Condi ons
The existing on-site runoff generally drains from the Northwest to the Southeast across flat grades
(e.g., 0.50% - 2.00%) towards the intersection of Duff Drive and Cordova Road. According to the
United States Department of Agriculture (USDA) Natural Resources Conservation Service (NRCS) Soil
Survey website: (http://websoilsurvey.nrcs.usda.gov/app/WebSoilSurvey.aspx), the site consists
primarily of Caruso Clay Loam (Hydrologic Soil Group D).
Groundwater was found to be present approximately 7-10 feet below existing ground elevations.
Proposed site development will maintain a minimum of 2 feet between existing groundwater levels
and proposed ground levels. The highest amount of cut on the site occurs where the proposed
detention ponds will be placed.
Table 1 - Groundwater Elevations vs. Proposed Elevations
Pond 1 Pond 2
Existing Ground Elevation 4940.80 4941.15
Groundwater Elevation 4932.80 4932.15
Proposed Elevation 4936.40 4935.00
Floodplain
The entirety of the site is located in a FEMA moderate-risk floodplain zone. There are no
special floodplain considerations required regarding finished floor elevations of building
footprints. A floodplain use permit will be required prior to construction for any work in the
floodplain.
Drainage Basins
Major Basin Description
The project area of The Landing at Lemay is located within the City of Fort Collins Dry Creek Drainage Basin.
Detention requirements for this basin are to detain the difference between the 100-yr developed inflow rate
and the historic 2-year release rate. However, outflow from this property is limited by release rates
determined for the Dry Creek Basin which are 0.2 cfs/acre. (17.5 ac * 0.2 cfs/ac = 3.5 cfs).
8
Sub-Basin Description
The outfall for the project site is at the south end of the project site to existing storm infrastructure in Duff
Drive. The existing subject site can be defined with 10 distinct drainage basins (see DR1 in the provided map
pocket). The existing site runoff generally drains from Northwest to Southeast towards proposed Cordova
Road. The project area receives offsite runoff from the northeast. This is accounted for in the drainage design
for this project site.
Drainage Design Criteria
Optional Provisions
There are no optional provisions outside of the FCSCM proposed with Landing at Lemay.
Stormwater Management Strategy
The overall stormwater management strategy employed with The Landing at Lemay utilizes the “Four Step
Process” to minimize adverse impacts of urbanization on receiving waters. The following is a description of
how the proposed development has incorporated each step.
Step 1 – Employ Runoff Reduction Practices. The first consideration taken in trying to reduce the stormwater
impacts of this development is the site selection itself. By choosing an already developed site with public
storm sewer currently in place, the burden is significantly less than developing a vacant parcel absent of any
infrastructure.
The Landing at Lemay aims to reduce runoff peaks, volumes and pollutant loads from frequently occurring
storm events (i.e., water quality (i.e., 80th percentile) and 2-year storm events) by implementing Low Impact
Development (LID) strategies. Wherever practical, runoff will be routed across landscaped areas or through
a rain garden or water quality pond. These LID practices reduce the overall amount of impervious area, while
at the same time Minimizing Directly Connected Impervious Areas (MDCIA). The combined LID/MDCIA
techniques will be implemented, where practical, throughout the development, thereby slowing runoff and
increasing opportunities for infiltration.
Step 2 – Implement BMPs that Provide a Water Quality Capture Volume (WQCV) with Slow Release. The
efforts taken in Step 1 will help to minimize excess runoff from frequently occurring storm events; however,
urban development of this intensity will still have stormwater runoff leaving the site. The primary water
quality treatment will occur between several rain gardens between major parking areas of the property and
the existing detention ponds installed for Impala Redevelopment.
Step 3 – Stabilize Drainageways. While not directly applicable to this site, the project will pay one-time
stormwater development fees as well as ongoing monthly stormwater utility fees, both of which help achieve
citywide drainageway stability.
Step 4 – Implement Site Specific and Other Source Control BMPs. This step typically applies to industrial and
commercial developments.
9
Development Criteria Reference and Constraints
The subject property is not part of an overall development plan. The project area is constrained to the west
by N Lemay Avenue, to the north by undeveloped open space, to the east by industrial buildings, and to
south by The Cottages of Fort Collins.
Hydrologic Design Criteria
The City of Fort Collins Rainfall Intensity-Duration-Frequency Curves, as depicted in Figure 3.4-1 of the
FCSCM, serve as the source for all hydrologic computations associated with The Landing at Lemay project.
Tabulated data contained in Table 3.4-1 has been utilized for Rational Method runoff calculations.
The Rational Method has been used to estimate peak developed stormwater runoff from drainage basins
within the developed site for the 2-year, 10-year, and 100-year design storms. Peak runoff discharges
determined using this methodology will be used to check the street capacities, inlets, swales, and storm
drain lines at final design.
Two separate design storms have been utilized to address distinct drainage scenarios. The first event
analyzed is the “Minor,” or “Initial” Storm, which has a 2-year recurrence interval. The second event
considered is the “Major Storm,” which has a 100-year recurrence interval.
Hydraulic Design Criteria
The drainage facilities proposed with The Landing at Lemay project are designed in accordance with criteria
outlined in the FCSCM. As stated above, the subject property is located within a FEMA moderate-risk
floodplain, but is not located within a City regulated floodplain. There are no formal modifications outside
of the FCSCM proposed with Landing at Lemay.
Conformance with Water Quality Treatment Criteria
City Code requires that 100% of runoff from new or modified areas in a project site shall receive some sort
of water quality treatment, of which a majority of the site is receiving. Each proposed drainage basin features
or drains to an LID facility to treat runoff for water quality.
All onsite basins will receive water quality treatment either via a rain garden, underground chambers, or
within a detention pond.
Conformance with Low Impact Development (LID) Requirements
The project site will conform with the requirement to treat a minimum of 75% of new or modified impervious
area using a LID technique. The proposed project site will treat approximately 89.5% of new/modified
impervious area with LID. Four rain gardens and two banks of Stormtech chambers are responsible for
treating a majority of the impervious area on the site.
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Sizing of LID and WQ Facilities
Rain Gardens
The rain gardens were sized by first determining the required water quality capture volume (WQCV) for
Sub-Basins A, B, C, D, E, and M. Once the WQCV was identified, the rain garden area was sized for its
respective WQCV. The rain gardens will be constructed with a biomedia filter and underdrain. An
overflow inlet/spillway will be provided to provide safe conveyance of storms greater than the WQCV.
Stormtech Chambers
Stormtech chambers were used where rain gardens were not feasible due to available space – Sub-
Basins C & E in this instance. The chambers were sized by first determining the required WQCV for the
basin. Once the WQCV was identified, the chamber area was sized for its respective WQCV. The
chambers will be constructed with stone beds/backfill and underdrain. Overflows will spill directly into
the downstream detention pond.
Table 2 - LID Summary
Water Quality
WQCV was calculated for the site using UDFCD equations – Pond 1 does not treat for water quality;
Pond 2 provides the remaining water quality treatment for areas not already treated by LID facilities.
Drainage Facility Design
General Proposed Concept(s)
The main objective of The Landing at Lemay drainage design is to maintain existing drainage patterns,
while not adversely impacting adjacent properties. All storm drains on the site (which will be a private
utility) have been designed to convey 100-yr flows except for underground chamber networks which
Sq. Ft. Acres
A 97,267 2.23
61% Rain Garden A 1,600 2,039 59,333
B 66,289 1.52
78% Rain Garden B 1,398 1,507 51,705
C 151,371 3.48
53% Chambers C 2,169 2,226 80,227
D 69,230 1.59
63% Rain Garden D 1,138 1,401 43,615
E 166,253 3.82
62% Chambers E 2,696 2,771 103,077
J 13,363 0.31
82% n/a 0 0 n/a
K 19,755 0.45
77% n/a 0 0 n/a
L 27,767 0.64
57% n/a 0 0 n/a
M 107,554 2.47
79% Rain Garden M 2,310 2,377 84,968
N 43,656 1.00
16% n/a 0 0 n/a
Total 762,505 15.27 62% 11,311 12,321 422,924
AreaBasin ID Percent
Impervious LID ID
Total Impervious
Area Treated (ft2)
Required
Volume (ft3)
LID Summary per Basin
Provided
Volume (ft3)
11
are designed to convey minor-event flows.
Sub-Basin Descrip ons
Drainage for the project site has been analyzed using 16 drainage sub-basins, designated as sub-basins
A-E, J-N, and OS1. Sub-basins A-N are on-site basins. OS1 is an off-site basin whose flows are collected
in Detention Pond 2.
Sub-Basin A
Sub-Basin A is composed of multi-family residential rooftops, paved roadways, and a clubhouse
and pool. Flows from this basin travel via overland flow and curb and gutter flow to Rain Garden
A where they are treated for water quality.
Sub-Basin B
Sub-Basin B contains multi-family residential rooftops, garages, paved roadways, and a dog park.
These flows travel via overland flow and curb and gutter flow to Rain Garden B where they are
treated for water quality. From here, flows are routed to Detention Pond 1.
Sub-Basin C
Sub-Basin C is composed of multi-family residential rooftops, paved roadways and parking lots,
Rain Garden C and Detention Pond 2. Runoff travels via overland flow/curb and gutter to Chamber
Bank C, which treats these flows for water quality. Runoff will then be routed to Detention Pond
2 and then will be released via proposed outlet structure to existing storm drain offsite.
Sub-Basin D
Sub-Basin D consists of multi-family residential rooftops, paved roadways, parking, open space,
and Rain Garden D. Runoff travels via overland flow, curb and gutter, and storm pipe to Rain
Garden D where it is treated for water quality. Rain Garden D then releases to Detention Pond 2.
Overflows from Sub-Basin D are conveyed via surface drainage to Sub-Basin C and Pond 2.
Sub-Basin E
Sub-Basin E contains multi-family residential rooftops, garages, paved roadways and parking, Rain
Garden E, and Detention Pond 1. Flows from this basin travel via overland flow, curb and gutter
northeast towards a curb cut that conveys flows to Chamber Bank E. After being treated for water
quality, these flows continue into Detention Pond 1 which outfalls into Detention Pond 2 (ponds
in series), then to existing storm drain infrastructure offsite.
Sub-Basin J and K
Sub-Basins J and K are composed of a paved roadway on the east side of the proposed multifamily
development. Sub-basins J and K are captured and routed directly to Detention Pond 1 where
they will be treated for water quality before they are routed offsite. These sub-basins have been
evaluated for their future/ultimate condition, even though a portion of Cordova Road will not be
constructed with this project.
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Sub-Basin L
Sub-Basin L contains multi-family residential rooftops and open space. Flows from this basin travel
via overland flow into area inlets, where they are conveyed to Detention Pond 2 via storm drains.
Sub-Basin M
Sub-Basin M contains multi-family residential, garages, paved roadways and parking, and Rain
Garden M. Flows from this basin travel via overland flow and curb and gutter to the center of the
site where a curb cut conveys flows to Rain Garden E. After being treated for water quality, these
flows continue into Detention Pond 2 which outfalls to existing storm drain infrastructure offsite.
Overflows from Sub-Basin M are conveyed via surface drainage to Sub-Basin D.
Sub-Basin N
Sub-Basin N contains open space and walkways. Flows from this basin travel via overland flow
and a swale/concrete pan south towards an inlet that conveys flows via storm drain to Detention
Pond 2.
Sub-Basin OS1
Sub-Basin OS1 is composed of open space to the northwest of the proposed project site. The
natural landscape of this basin directs flow onto the project site and for this reason, they will be
routed through the site in a proposed swale with concrete pan. These flows are then captured in
a storm pipe and directed to Detention Pond 2.
Detention Details
There are 2 proposed detention ponds on the project site that will detain up to the 100-year storm event
and release at or below the allowed historic release for the Dry Creek Basin. See Table 3 for detention
summary.
Table 3 - Detention Summary
Project: 1791-003
By: ARS
Date: 3/1/24
Pond ID
Tributary
Area
(Ac)1
Weighted %
Imperviousness
(%)
Extended
Detention WQCV
(cu-ft)
WQCV Volume
provided by LID
facilities (cu-ft)
Extended
Detention WQCV
Provded (cu-ft)2
100-Yr.
Detention
Vol. (Ac-Ft)
100-Yr.
Detention
WSEL(Ft)
Peak Release
(cfs)3
Pond 1 6.10 68 4,716 --1.27 4942.20 2.50
Pond 2 11.41 59 7,713 1,118 2.76 4942.10 1.00
Notes:
1. Tributary area shown does not include off-site basin(s)
2. Total WQCV for site will be provded in Pond 2
3. Overall site release rate of 3.5 cfs divided between Ponds 1 and 2
POND SUMMARY TABLE
11,311
13
Detention Ponds 1 and 2 will be constructed in series; Pond 1 will capture flows from sub-basins B, J, and K.
Pond 2 will capture flows from sub-basins A, C, D, L, M, N, and OS1. The site has a previously established
allowed release rate of 3.5 cfs based on the master drainage basin; Pond 1 will release at 2.5 cfs, and Pond
2 will release at 1.0 cfs. Both Pond 1 and Pond 2 utilize outlet structures to achieve the desired release rate;
the outfall pipe into existing storm infrastructure for Pond 2 features a 2nd inlet/spill point downstream of
the outlet structure which has been set at the 100-year WSEL of Pond 1 (which is higher in elevation than
the 100-year WSEL of Pond 2) and will act as the overflow point for Pond 1.
LID treatment is being provided within rain gardens and underground chambers. These treat approximately
92.15% of the modified site impervious runoff, which is more than the required 75% LID treatment. Please
see the LID exhibit and calculations in Appendix C. The required WQCV for areas not treated by LID facilities
- 1,115 cubic feet - will be provided in Pond 2.
The detention allowable release rate is based on the allowed release rate from the Dry Creek Basin, which is
0.2 cfs/acre. Stormwater facility Standard Operations Procedures (SOP) will be provided by the City of Fort
Collins in the Development Agreement.
Conclusions
Compliance With Standards
The drainage design proposed with The Landing at Lemay complies with the City of Fort Collins Master
Drainage Plan for the Canal Importation Basin. The drainage plan and stormwater management measures
proposed with The Landing at Lemay project are compliant with all applicable State and Federal regulations
governing stormwater discharge.
Drainage Concepts
The drainage plan and stormwater management measures proposed with The Landing at Lemay project are
compliant with all applicable regulations governing stormwater discharge. The Landing at Lemay will not
impact the Master Drainage Plan recommendations for the Fort Collins Dry Creek Major Drainage Basin.
14
References
1. Fort Collins Stormwater Criteria Manual, City of Fort Collins, Colorado, as adopted by Ordinance No.
159, 2018, and referenced in Section 26-500 of the City of Fort Collins Municipal Code.
2. Soils Resource Report for Larimer County Area, Colorado, Natural Resources Conservation Service,
United States Department of Agriculture.
3. Urban Storm Drainage Criteria Manual, Volumes 1-3, Urban Drainage and Flood Control District,
Wright- McLaughlin Engineers, Denver, Colorado, Revised April 2008.
A
APPENDIX A – HYDROLOGIC CALCULATIONS
CHARACTER OF SURFACE1:
Percentage
Impervious
2-yr Runoff
Coefficient
100-yr Runoff
Coefficient
Developed
Asphalt .…………………………..……………………………………………….…………………………..……………………………………………….…………………………..……………………………………………….…………………………..………………………………………………100% 0.95 1.00
Concrete .…………………………..……………………………………………….…………………………..……………………………………………….…………………………..……………………………………………….…………………………..………………………………………………100% 0.95 1.00
Rooftop .…………………………..……………………………………………….…………………………..……………………………………………….…………………………..……………………………………………….…………………………..………………………………………………90% 0.95 1.00
Gravel .…………………………..……………………………………………….…………………………..……………………………………………….…………………………..……………………………………………….…………………………..………………………………………………40% 0.50 0.63
Pavers .…………………………..……………………………………………….…………………………..……………………………………………….…………………………..……………………………………………….…………………………..………………………………………………40% 0.50 0.63
Landscape or Pervious Surface
Playgrounds .…………………………..……………………………………………….…………………………..……………………………………………….…………………………..……………………………………………….…………………………..………………………………………………25% 0.35 0.44
Lawns Clayey Soil .…………………………..……………………………………………….…………………………..……………………………………………….…………………………..……………………………………………….…………………………..………………………………………………2% 0.25 0.31
Lawns Sandy Soil .…………………………..……………………………………………….…………………………..……………………………………………….…………………………..……………………………………………….…………………………..……………………………………………….…………………………..……………………………………………….…………………………..………………………………………………2%0.15 0.19
Notes:
Basin ID Basin Area
(ac)
Area of
Asphalt
(ac)
Area of
Concrete
(ac)
Area of
Rooftop
(ac)
Area of
Gravel
(ac)
Area of
Pavers
(ac)
Area of
Playgrounds
(ac)
Area of Lawns
(ac)
Composite
% Imperv.
2-year
Composite Runoff
Coefficient
100-year
Composite
Runoff
Coefficient
A 2.267 0.780 0.181 0.485 0.00 0.00 0.00 0.821 62% 0.70 0.88
B 1.522 0.771 0.09 0.359 0.00 0.00 0.00 0.300 78% 0.81 1.00
C 3.475 1.040 0.21 0.617 0.00 0.00 0.00 1.609 53% 0.63 0.79
D 1.589 0.409 0.17 0.459 0.00 0.00 0.00 0.553 63% 0.71 0.89
E 3.817 1.431 0.34 0.644 0.00 0.00 0.00 1.398 62% 0.69 0.86
J 0.307 0.209 0.04 0.000 0.00 0.00 0.00 0.055 82% 0.82 1.00
K 0.454 0.346 0.00 0.000 0.00 0.00 0.00 0.107 77% 0.78 0.98
L 0.637 0.000 0.06 0.332 0.00 0.00 0.00 0.244 57% 0.68 0.85
M 2.469 1.061 0.27 0.682 0.00 0.00 0.00 0.458 79% 0.82 1.00
N 0.968 0.029 0.08 0.000 0.862 13% 0.33 0.41
OS1 0.906 0.000 0.00 0.000 0.00 0.00 0.00 0.906 2% 0.25 0.31
Detention Pond 1 (B, E, J, K) 6.099 2.757 0.478 1.003 0.000 0.000 0.000 1.861 68% 0.73 0.91
Detention Pond 2 (A, C, D, L, M, N) 11.406 3.319 0.965 2.575 0.000 0.000 0.000 4.547 59% 0.67 0.84
DEVELOPED BASIN % IMPERVIOUSNESS AND RUNOFF COEFFICIENT CALCULATIONS
2) Runoff Coefficients are taken from the Fort Collins Stormwater Criteria Manual, Chapter 3. Table 3.2-1 and 3.2-2
1) Percentage impervious taken from the Fort Collins Stormwater Criteria Manual, Chapter 5, Table 4.1-2 and Table 4.1-3
Combined Basins
Overland Flow, Time of Concentration:
Channelized Flow, Time of Concentration:
UPDATE
Total Time of Concentration :
T c is the lesser of the values of Tc calculated using T c = T i + T t
C5 C100
Length,
L
(ft)
Slope,
S
(%)
Ti5 Ti100
Length,
L
(ft)
Slope,
S
(%)
Roughness
Coefficient
Assumed
Hydraulic
Radius
Velocity,
V
(ft/s)
Tt
(min)Tc (Eq. 3.3-5) Tc2 = Ti +Tt Tc100 = Ti +Tt Tc5 Tc100
a A 0.70 0.88 46 0.87% 5.3 3.0 376 0.51% 0.015 0.15 4.41 2.0 12.3 7.3 5.0 7.3 5.0
b B 0.81 1.00 192 0.55% 9.2 1.3 351 0.56% 0.015 0.15 3.92 2.1 13.0 11.3 3.4 11.3 5.0
c C 0.63 0.79 81 0.60% 9.4 4.2 403 0.76% 0.015 0.15 3.86 2.4 12.7 11.8 6.6 11.8 6.6
d D 0.71 0.89 49 1.43% 4.5 2.8 346 0.58% 0.015 0.15 3.79 2.1 12.2 6.7 5.0 6.7 5.0
e E 0.69 0.86 64 1.74% 5.1 3.2 149 1.47% 0.015 0.15 1.02 3.4 11.2 8.5 6.6 8.5 6.6
j J 0.82 1.00 26 2.46% 2.0 1.3 198 0.49% 0.015 0.15 2.36 2.0 11.2 3.9 3.3 5.0 5.0
k K 0.78 0.98 26 2.38% 2.3 1.7 201 0.50% 0.015 0.15 2.36 2.0 11.3 4.3 3.6 5.0 5.0
l L 0.68 0.85 249 0.80% 13.3 3.3 0 N/A 0.015 0.15 N/A N/A 11.4 13.3 3.3 11.4 5.0
m M 0.82 1.00 25 1.20% 2.5 1.3 444 0.52% 0.015 0.15 5.13 2.0 12.6 4.5 3.4 5.0 5.0
n N 0.33 0.41 38 1.97% 7.1 9.1 824 0.28% 0.015 0.59 12.97 3.7 14.8 10.8 12.8 10.8 12.8
DEVELOPED DIRECT TIME OF CONCENTRATION
Channelized Flow
Design
Point Basin
Overland Flow Time of Concentration
Frequency Adjustment Factor:
(Equation 3.3-2 FCSCM)
(Equation 5-5 FCSCM)
(Equation 5-4 FCSCM)
(Equation 3.3-5 FCSCM)
Table 3.2-3 FCSCM
Therefore Tc2=Tc10 Notes:
1) Add 4900 to all elevations.
2) Per Fort Collins Stormwater Manual, minimum Tc = 5 min.
3) Assume a water depth of 6" and a typical curb and gutter per Larimer
County Urban Street Standard Detail 701 for curb and gutter channelized
flow. Assume a water depth of 1', fixed side slopes, and a triangular swale
section for grass channelized flow. Assume a water depth of 1', 4:1 side
slopes, and a 2' wide valley pan for channelized flow in a valley pan.
Rational Method Equation:
Rainfall Intensity:
a 2.27 5.0 0.88 2.85 9.95 4.52 19.73
b 1.52 5.0 1.00 2.85 9.95 3.51 15.14
c 3.48 6.6 0.79 2.60 9.06 5.68 24.78
d 1.59 5.0 0.89 2.85 9.95 3.22 14.03
e 3.82 6.6 0.86 2.60 9.06 6.83 29.81
j 0.31 5.0 1.00 2.85 9.95 0.72 3.05
k 0.45 5.0 0.98 2.85 9.95 1.01 4.40
l 0.64 5.0 0.85 2.85 9.95 1.24 5.39
m 2.47 5.0 1.00 2.85 9.95 5.77 24.57
n 0.97 12.8 0.41 2.02 7.04 0.64 2.81
OS1 0.91 14.2 0.31 1.92 6.71 0.43 1.90
DEVELOPED RUNOFF COMPUTATIONS
Design
Point
Area, A
(acres)
Flow,
Q2
(cfs)
Flow,
Q100
(cfs)
C100
IDF Table for Rational Method - Table 3.4-1 FCSCM
Tc100
(min)
Intensity,
i2
(in/hr)
Intensity,
i100
(in/hr)
()()()AiCCQf=
B
APPENDIX B – HYDRAULIC CALCULATIONS
Project: 1791-003
By: ARS
Date: 3/1/24
Pond ID
Tributary
Area
(Ac)1
Weighted %
Imperviousness
(%)
Extended
Detention WQCV
(cu-ft)
WQCV Volume
provided by LID
facilities (cu-ft)
Extended
Detention WQCV
Provded (cu-ft)2
100-Yr.
Detention
Vol. (Ac-Ft)
100-Yr.
Detention
WSEL(Ft)
Peak Release
(cfs)3
Pond 1 6.10 68 4,716 --1.27 4942.20 2.50
Pond 2 11.41 59 7,713 1,118 2.76 4942.10 1.00
Notes:
1. Tributary area shown does not include off-site basin(s)
2. Total WQCV for site will be provded in Pond 2
3. Overall site release rate of 3.5 cfs divided between Ponds 1 and 2
POND SUMMARY TABLE
11,311
POND 1
AS
Pond No :Pond 1
100-yr
0.91
Area (A)=6.09 acres 55419 ft3
Max Release Rate =2.50 cfs 1.27 ac-ft
Time Time
100-yr
Intensity Q100
Inflow
(Runoff)
Volume
Outflow
(Release)
Volume
Storage
Detention
Volume
(mins) (secs) (in/hr) (cfs)
(ft3) (ft
3) (ft
3)
5 300 9.950 55.14 16543 750.0 15792.6
10 600 7.720 42.78 25670 1500.0 24170.1
15 900 6.520 36.13 32520 2250.0 30269.9
20 1200 5.600 31.03 37242 3000.0 34241.6
25 1500 4.980 27.60 41398 3750.0 37648.0
30 1800 4.520 25.05 45089 4500.0 40588.9
35 2100 4.080 22.61 47483 5250.0 42233.0
40 2400 3.740 20.73 49744 6000.0 43744.1
45 2700 3.460 19.17 51772 6750.0 45022.4
50 3000 3.230 17.90 53701 7500.0 46201.0
55 3300 3.030 16.79 55413 8250.0 47163.5
60 3600 2.860 15.85 57059 9000.0 48059.4
65 3900 2.720 15.07 58788 9750.0 49038.5
70 4200 2.590 14.35 60285 10500.0 49784.8
75 4500 2.480 13.74 61848 11250.0 50597.6
80 4800 2.380 13.19 63311 12000.0 51310.7
85 5100 2.290 12.69 64724 12750.0 51973.9
90 5400 2.210 12.25 66137 13500.0 52637.0
95 5700 2.130 11.80 67284 14250.0 53034.2
100 6000 2.060 11.42 68498 15000.0 53497.9
105 6300 2.000 11.08 69828 15750.0 54077.9
110 6600 1.940 10.75 70958 16500.0 54458.5
115 6900 1.890 10.47 72272 17250.0 55021.9
120 7200 1.840 10.20 73419 18000.0 55419.1
DETENTION POND CALCULATION; FAA METHOD
Project Number : 1791-003
Design Storm Required Detention Volume
Developed "C" =
Project Location : Fort Collins
Input Variables Results
Calculations By:
Project:
Basin ID:
Depth Increment = 0.20 ft
Watershed Information Top of Micropool -- 0.00 -- -- -- 0 0.000
Selected BMP Type =EDB 4,937.60 -- 0.20 -- -- -- 121 0.003 12 0.000
Watershed Area = 6.09 acres 4,937.80 -- 0.40 -- -- -- 690 0.016 93 0.002
Watershed Length = 875 ft 4,938.00 -- 0.60 -- -- -- 1,685 0.039 331 0.008
Watershed Length to Centroid = 550 ft 4,938.20 -- 0.80 -- -- -- 3,141 0.072 813 0.019
Watershed Slope = 0.009 ft/ft 4,938.40 -- 1.00 -- -- -- 4,882 0.112 1,616 0.037
Watershed Imperviousness = 68.00% percent 4,938.60 -- 1.20 -- -- -- 6,797 0.156 2,784 0.064
Percentage Hydrologic Soil Group A = 0.0% percent 4,938.80 -- 1.40 -- -- -- 8,630 0.198 4,326 0.099
Percentage Hydrologic Soil Group B = 0.0% percent 4,939.00 -- 1.60 -- -- -- 10,414 0.239 6,231 0.143
Percentage Hydrologic Soil Groups C/D = 100.0% percent 4,939.20 -- 1.80 -- -- -- 11,856 0.272 8,458 0.194
Target WQCV Drain Time = 40.0 hours 4,939.40 -- 2.00 -- -- -- 12,834 0.295 10,927 0.251
Location for 1-hr Rainfall Depths = User Input 4,939.60 -- 2.20 -- -- -- 13,456 0.309 13,556 0.311
4,939.80 -- 2.40 -- -- -- 13,858 0.318 16,287 0.374
4,940.00 -- 2.60 -- -- -- 14,255 0.327 19,098 0.438
Optional User Overrides 4,940.20 -- 2.80 -- -- -- 14,655 0.336 21,989 0.505
Water Quality Capture Volume (WQCV) = 0.135 acre-feet acre-feet 4,940.40 -- 3.00 -- -- -- 15,057 0.346 24,961 0.573
Excess Urban Runoff Volume (EURV) = 0.402 acre-feet acre-feet 4,940.60 -- 3.20 -- -- -- 15,463 0.355 28,013 0.643
2-yr Runoff Volume (P1 = 0.82 in.) = 0.260 acre-feet 0.82 inches 4,940.80 -- 3.40 -- -- -- 15,871 0.364 31,146 0.715
5-yr Runoff Volume (P1 = 1.14 in.) = 0.399 acre-feet 1.14 inches 4,941.00 -- 3.60 -- -- -- 16,284 0.374 34,362 0.789
10-yr Runoff Volume (P1 = 1.4 in.) = 0.527 acre-feet 1.40 inches 4,941.20 -- 3.80 -- -- -- 16,819 0.386 37,672 0.865
25-yr Runoff Volume (P1 = 1.81 in.) = 0.753 acre-feet 1.81 inches 4,941.40 -- 4.00 -- -- -- 17,478 0.401 41,102 0.944
50-yr Runoff Volume (P1 = 2.27 in.) = 0.996 acre-feet 2.27 inches 4,941.60 -- 4.20 -- -- -- 18,025 0.414 44,652 1.025
100-yr Runoff Volume (P1 = 2.86 in.) = 1.322 acre-feet 2.86 inches 4,941.80 -- 4.40 -- -- -- 18,456 0.424 48,300 1.109
500-yr Runoff Volume (P1 = 4.39 in.) = 2.155 acre-feet 4.39 inches 4,942.00 -- 4.60 -- -- -- 18,890 0.434 52,034 1.195
Approximate 2-yr Detention Volume = 0.248 acre-feet 4,942.20 -- 4.80 -- -- -- 19,327 0.444 55,856 1.282
Approximate 5-yr Detention Volume = 0.384 acre-feet ---- -- --
Approximate 10-yr Detention Volume = 0.463 acre-feet -- -- -- --
Approximate 25-yr Detention Volume = 0.558 acre-feet -- -- -- --
Approximate 50-yr Detention Volume = 0.639 acre-feet -- -- -- --
Approximate 100-yr Detention Volume = 0.780 acre-feet -- -- -- --
-- -- -- --
Define Zones and Basin Geometry -- -- -- --
Zone 1 Volume (User Defined) = 0.037 acre-feet -- -- -- --
Zone 2 Volume (User Defined - Zone 1) = 1.233 acre-feet -- -- -- --
Select Zone 3 Storage Volume (Optional) = acre-feet -- -- -- --
Total Detention Basin Volume = 1.270 acre-feet -- -- -- --
Initial Surcharge Volume (ISV) = user ft 3 -- -- -- --
Initial Surcharge Depth (ISD) = user ft -- -- -- --
Total Available Detention Depth (Htotal) =user ft -- -- -- --
Depth of Trickle Channel (HTC) =user ft -- -- -- --
Slope of Trickle Channel (STC) =user ft/ft -- -- -- --
Slopes of Main Basin Sides (Smain) =user H:V -- -- -- --
Basin Length-to-Width Ratio (RL/W) =user -- -- -- --
-- -- -- --
Initial Surcharge Area (AISV) =user ft 2 -- -- -- --
Surcharge Volume Length (LISV) =user ft -- -- -- --
Surcharge Volume Width (WISV) =user ft -- -- -- --
Depth of Basin Floor (HFLOOR) =user ft -- -- -- --
Length of Basin Floor (LFLOOR) =user ft -- -- -- --
Width of Basin Floor (WFLOOR) =user ft -- -- -- --
Area of Basin Floor (AFLOOR) =user ft 2 -- -- -- --
Volume of Basin Floor (VFLOOR) =user ft 3 -- -- -- --
Depth of Main Basin (HMAIN) =user ft -- -- -- --
Length of Main Basin (LMAIN) =user ft -- -- -- --
Width of Main Basin (WMAIN) =user ft -- -- -- --
Area of Main Basin (AMAIN) =user ft 2 -- -- -- --
Volume of Main Basin (VMAIN) =user ft 3 -- -- -- --
Calculated Total Basin Volume (Vtotal) =user acre-feet -- -- -- --
--------
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WQCV not provided!
After providing required inputs above including 1-hour rainfall
depths, click 'Run CUHP' to generate runoff hydrographs using
the embedded Colorado Urban Hydrograph Procedure.
Volume
(ft 3)
Volume
(ac-ft)
Area
(acre)
DETENTION BASIN STAGE-STORAGE TABLE BUILDER
Optional
Override
Area (ft 2)
Length
(ft)
Optional
Override
Stage (ft)
Stage
(ft)
Stage - Storage
Description
Area
(ft 2)
Width
(ft)
Landing at Lemay
Pond 1
MHFD-Detention, Version 4.06 (July 2022)
Example Zone Configuration (Retention Pond)
MHFD-Detention_v4-06 - Pond 1, Basin 3/5/2024, 10:43 AM
1 User Defined Stage-Area Booleans for Message
1 Equal Stage-Area Inputs Watershed L:W
1 CountA Watershed Lc:L
Watershed Slope
0 Calc_S_TC Booleans for CUHP
1 CUHP Inputs Complete
0.49 H_FLOOR 1 CUHP Results Calculated
L_FLOOR_OTHER
0.00 ISV 0.00 ISV
0.00 Floor 0.00 Floor
1.00 Zone 1 (User) 1.00 Zone 1 (User)
4.78 Zone 2 (User) 4.78 Zone 2 (User)
0.00 Zone 3 0.00 Zone 3
DETENTION BASIN STAGE-STORAGE TABLE BUILDER
MHFD-Detention, Version 4.06 (July 2022)
0.000
0.325
0.650
0.975
1.300
0.000
0.115
0.230
0.345
0.460
0.00 1.50 3.00 4.50 6.00
Vo
l
u
m
e
(
a
c
-
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t
)
Ar
e
a
(
a
c
r
e
s
)
Stage (ft.)
Area (acres)Volume (ac-ft)
0
4900
9800
14700
19600
0
5
10
15
20
0.00 1.50 3.00 4.50 6.00
Ar
e
a
(
s
q
.
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t
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Le
n
g
t
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,
W
i
d
t
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(
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Stage (ft)
Length (ft)Width (ft)Area (sq.ft.)
MHFD-Detention_v4-06 - Pond 1, Basin 3/5/2024, 10:43 AM
Project:
Basin ID:
Estimated Estimated
Stage (ft) Volume (ac-ft) Outlet Type
Zone 1 (User) 1.00 0.037 Rectangular Orifice
Zone 2 (User) 4.78 1.233 Weir&Pipe (Circular)
Zone 3 Not Utilized
Total (all zones) 1.270
User Input: Orifice at Underdrain Outlet (typically used to drain WQCV in a Filtration BMP)Calculated Parameters for Underdrain
Underdrain Orifice Invert Depth = N/A ft (distance below the filtration media surface) Underdrain Orifice Area = N/A ft2
Underdrain Orifice Diameter = N/A inches Underdrain Orifice Centroid = N/A feet
User Input: Orifice Plate with one or more orifices or Elliptical Slot Weir (typically used to drain WQCV and/or EURV in a sedimentation BMP)Calculated Parameters for Plate
Centroid of Lowest Orifice = N/A ft (relative to basin bottom at Stage = 0 ft) WQ Orifice Area per Row = N/A ft2
Depth at top of Zone using Orifice Plate = N/A ft (relative to basin bottom at Stage = 0 ft) Elliptical Half-Width = N/A feet
Orifice Plate: Orifice Vertical Spacing = N/A inches Elliptical Slot Centroid = N/A feet
Orifice Plate: Orifice Area per Row = N/A sq. inches Elliptical Slot Area = N/A ft2
User Input: Stage and Total Area of Each Orifice Row (numbered from lowest to highest)
Row 1 (optional) Row 2 (optional) Row 3 (optional) Row 4 (optional) Row 5 (optional) Row 6 (optional) Row 7 (optional) Row 8 (optional)
Stage of Orifice Centroid (ft) N/A N/A N/A N/A N/A N/A N/A N/A
Orifice Area (sq. inches) N/A N/A N/A N/A N/A N/A N/A N/A
Row 9 (optional) Row 10 (optional) Row 11 (optional) Row 12 (optional) Row 13 (optional) Row 14 (optional) Row 15 (optional) Row 16 (optional)
Stage of Orifice Centroid (ft) N/A N/A N/A N/A N/A N/A N/A N/A
Orifice Area (sq. inches) N/A N/A N/A N/A N/A N/A N/A N/A
User Input: Vertical Orifice (Circular or Rectangular)Calculated Parameters for Vertical Orifice
Zone 1 Rectangular Not Selected Zone 1 Rectangular Not Selected
Invert of Vertical Orifice = 0.00 N/A ft (relative to basin bottom at Stage = 0 ft) Vertical Orifice Area = 0.25 N/A ft2
Depth at top of Zone using Vertical Orifice = 1.00 N/A ft (relative to basin bottom at Stage = 0 ft) Vertical Orifice Centroid = 0.50 N/A feet
Vertical Orifice Height = 12.00 N/A inches
Vertical Orifice Width = 3.00 inches
User Input: Overflow Weir (Dropbox with Flat or Sloped Grate and Outlet Pipe OR Rectangular/Trapezoidal Weir and No Outlet Pipe) Calculated Parameters for Overflow Weir
grate Zone 2 Weir Not Selected Zone 2 Weir Not Selected
Overflow Weir Front Edge Height, Ho = 1.00 N/A ft (relative to basin bottom at Stage = 0 ft)Height of Grate Upper Edge, Ht =1.75 N/A feet
Overflow Weir Front Edge Length = 3.00 N/A feet Overflow Weir Slope Length = 3.09 N/A feet
Overflow Weir Grate Slope = 4.00 N/A H:V Grate Open Area / 100-yr Orifice Area = 27.46 N/A
Horiz. Length of Weir Sides = 3.00 N/A feet Overflow Grate Open Area w/o Debris = 7.34 N/A ft2
Overflow Grate Type = Close Mesh Grate N/A Overflow Grate Open Area w/ Debris = 3.67 N/A ft2
Debris Clogging % = 50% N/A %
User Input: Outlet Pipe w/ Flow Restriction Plate (Circular Orifice, Restrictor Plate, or Rectangular Orifice)Calculated Parameters for Outlet Pipe w/ Flow Restriction Plate
Zone 2 Circular Not Selected Zone 2 Circular Not Selected
Depth to Invert of Outlet Pipe = 0.01 N/A ft (distance below basin bottom at Stage = 0 ft)Outlet Orifice Area = 0.27 N/A ft2
Circular Orifice Diameter = 7.00 N/A inches Outlet Orifice Centroid = 0.29 N/A feet
Half-Central Angle of Restrictor Plate on Pipe = N/A N/A radians
User Input: Emergency Spillway (Rectangular or Trapezoidal)Calculated Parameters for Spillway
Spillway Invert Stage= ft (relative to basin bottom at Stage = 0 ft) 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 Basin Volume at Top of Freeboard = acre-ft
Max Ponding Depth of Target Storage Volume =4.80 feet Discharge at Top of Freeboard = cfs
Routed Hydrograph Results
Design Storm Return Period =WQCV EURV 2 Year 5 Year 10 Year 25 Year 50 Year 100 Year 500 Year
One-Hour Rainfall Depth (in) =N/A N/A 0.82 1.14 1.40 1.81 2.27 2.86 4.39
CUHP Runoff Volume (acre-ft) =0.135 0.402 0.260 0.399 0.527 0.753 0.996 1.322 2.155
Inflow Hydrograph Volume (acre-ft) =N/A N/A 0.260 0.399 0.527 0.753 0.996 1.322 2.155
CUHP Predevelopment Peak Q (cfs) =N/A N/A 0.0 0.5 1.3 3.3 5.0 7.5 13.3
OPTIONAL Override Predevelopment Peak Q (cfs) =N/A N/A
Predevelopment Unit Peak Flow, q (cfs/acre) =N/A N/A 0.01 0.09 0.21 0.54 0.82 1.23 2.18
Peak Inflow Q (cfs) =N/A N/A 3.3 5.1 6.7 9.9 13.1 17.5 28.1
Peak Outflow Q (cfs) =1.4 1.9 1.4 1.6 1.7 2.0 2.2 2.5 2.7
Ratio Peak Outflow to Predevelopment Q =N/A N/A N/A 3.0 1.3 0.6 0.4 0.3 0.2
Structure Controlling Flow =Outlet Plate 1 Outlet Plate 1 Outlet Plate 1 Outlet Plate 1 Outlet Plate 1 Outlet Plate 1 Outlet Plate 1 Outlet Plate 1 N/A
Max Velocity through Grate 1 (fps) =0.03 0.03 0.03 0.0 0.0 0.0 0.0 0.0 0.0
Max Velocity through Grate 2 (fps) =N/A N/A N/A N/A N/A N/A N/A N/A N/A
Time to Drain 97% of Inflow Volume (hours) =2 3 3 4 5 6 7 8 11
Time to Drain 99% of Inflow Volume (hours) =2 4 3 4 5 6 7 9 12
Maximum Ponding Depth (ft) =1.57 2.49 1.39 1.79 2.11 2.74 3.32 4.09 4.80
Area at Maximum Ponding Depth (acres) =0.23 0.32 0.20 0.27 0.30 0.33 0.36 0.41 0.44
Maximum Volume Stored (acre-ft) =0.136 0.403 0.097 0.191 0.284 0.485 0.686 0.976 1.282
DETENTION BASIN OUTLET STRUCTURE DESIGN
MHFD-Detention, Version 4.06 (July 2022)
Landing at Lemay
Pond 1
The user can override the default CUHP hydrographs and runoff volumes by entering new values in the Inflow Hydrographs table (Columns W through AF).
Example Zone Configuration (Retention Pond)
MHFD-Detention_v4-06 - Pond 1, Outlet Structure 3/5/2024, 10:43 AM
COUNTA for Basin Tab = 1 Ao Dia WQ Plate Type Vert Orifice 1Vert Orifice 2
Count_Underdrain = 0 0.11(diameter = 3/8 inch)1 3 1
Count_WQPlate = 0 0.14(diameter = 7/16 inch)
Count_VertOrifice1 = 1 0.18(diameter = 1/2 inch)Outlet Plate 1 Outlet Plate 2 Drain Time Message Boolean
Count_VertOrifice2 = 0 0.24(diameter = 9/16 inch)2 1 5yr, <72hr 0
Count_Weir1 = 1 0.29(diameter = 5/8 inch)>5yr, <120hr 0
Count_Weir2 = 0 0.36(diameter = 11/16 inch)Max Depth Row
Count_OutletPipe1 = 1 0.42(diameter = 3/4 inch)WQCV 158
Count_OutletPipe2 = 0 0.50(diameter = 13/16 inch)2 Year 140
COUNTA_2 (Standard FSD Setup)= 0 0.58(diameter = 7/8 inch)EURV 250
Hidden Parameters & Calculations 0.67(diameter = 15/16 inch)5 Year 180
MaxPondDepth_Error? FALSE 0.76 (diameter = 1 inch)10 Year 212 Spillway Depth
Cd_Broad-Crested Weir 3.00 0.86(diameter = 1-1/16 inches)25 Year 275
WQ Plate Flow at 100yr depth = 0.00 0.97(diameter = 1-1/8 inches)50 Year 333
CLOG #1= 50% 1.08(diameter = 1-3/16 inches)100 Year 410 1 Z1_Boolean
n*Cdw #1 = 0.44 1.20(diameter = 1-1/4 inches)500 Year 481 1 Z2_Boolean
n*Cdo #1 = 1.83 1.32(diameter = 1-5/16 inches)Zone3_Pulldown Message 1 Z3_Boolean
Overflow Weir #1 Angle = 0.245 1.45(diameter = 1-3/8 inches)1 Opening Message
CLOG #2= N/A 1.59(diameter = 1-7/16 inches)Draintime Running
n*Cdw #2 = N/A 1.73(diameter = 1-1/2 inches)Outlet Boolean Outlet Rank Total (1 to 4)
n*Cdo #2 = N/A 1.88(diameter = 1-9/16 inches)Vertical Orifice 1 1 1
2
Overflow Weir #2 Angle = N/A 2.03(diameter = 1-5/8 inches)Vertical Orifice 2 0 0 Boolean
Underdrain Q at 100yr depth = 0.00 2.20(diameter = 1-11/16 inches)Overflow Weir 1 1 2 0 Max Depth
VertOrifice1 Q at 100yr depth = 2.28 2.36(diameter = 1-3/4 inches)Overflow Weir 2 0 0 0 500yr Depth
VertOrifice2 Q at 100yr depth = 0.00 2.54(diameter = 1-13/16 inches)Outlet Pipe 1 1 2 1 Freeboard
2.72(diameter = 1-7/8 inches)Outlet Pipe 2 0 0 0 Spillway
Count_User_Hydrographs 0 2.90(diameter = 1-15/16 inches)0 Spillway Length
CountA_3 (EURV & 100yr) = 1 3.09(diameter = 2 inches)FALSE Time Interval
CountA_4 (100yr Only) = 1 3.29(use rectangular openings)Button Visibility Boolean
COUNTA_5 (FSD Weir Only)= 0 0 WQCV Underdrain
COUNTA_6 (EURV Weir Only)= 1 0 WQCV Plate
0 EURV-WQCV Plate
Outlet1_Pulldown_Boolean 0 EURV-WQCV VertOriice
Outlet2_Pulldown_Boolean 0 Outlet 90% Qpeak
Outlet3_Pulldown_Boolean 1 Outlet Undetained
0 Weir Only 90% Qpeak
0 Five Year Ratio Plate
0 Five Year Ratio VertOrifice
EURV_draintime_user
Spillway Options
Offset
Overlapping
S-A-V-D Chart Axis Default X-axis Left Y-Axis Right Y-Axis
minimum bound 0.00 0 0
maximum bound 6.00 60,000 10
S-A-V-D Chart Axis Override X-axis Left Y-Axis Right Y-Axis
minimum bound
maximum bound
DETENTION BASIN OUTLET STRUCTURE DESIGN
MHFD-Detention, Version 4.06 (July 2022)
0
5
10
15
20
25
30
0.1 1 10
FL
O
W
[
c
f
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TIME [hr]
500YR IN
500YR OUT
100YR IN
100YR OUT
50YR IN
50YR OUT
25YR IN
25YR OUT
10YR IN
10YR OUT
5YR IN
5YR OUT
2YR IN
2YR OUT
EURV IN
EURV OUT
WQCV IN
WQCV OUT
0
1
2
3
4
5
6
0.1 1 10 100
PO
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DRAIN TIME [hr]
500YR
100YR
50YR
25YR
10YR
5YR
2YR
EURV
WQCV
0
1
2
3
4
5
6
7
8
9
10
0
10,000
20,000
30,000
40,000
50,000
60,000
0.00 1.00 2.00 3.00 4.00 5.00 6.00
OU
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PONDING DEPTH [ft]
User Area [ft^2]
Interpolated Area [ft^2]
Summary Area [ft^2]
Volume [ft^3]
Summary Volume [ft^3]
Outflow [cfs]
Summary Outflow [cfs]
MHFD-Detention_v4-06 - Pond 1, Outlet Structure 3/5/2024, 10:43 AM
POND 2
ARS
Pond No :Pond 2
100-yr
0.84
Area (A)=11.46 acres 120331 ft3
Max Release Rate =1.00 cfs 2.76 ac-ft
Time Time
100-yr
Intensity Q100
Inflow
(Runoff)
Volume
Outflow
(Release)
Volume
Storage
Detention
Volume
(mins) (secs) (in/hr) (cfs)
(ft3) (ft
3) (ft
3)
5 300 9.950 95.78 28735 300.0 28434.8
10 600 7.720 74.32 44589 600.0 43989.5
15 900 6.520 62.76 56488 900.0 55587.7
20 1200 5.600 53.91 64689 1200.0 63489.4
25 1500 4.980 47.94 71909 1500.0 70409.2
30 1800 4.520 43.51 78320 1800.0 76520.4
35 2100 4.080 39.28 82479 2100.0 80379.0
40 2400 3.740 36.00 86407 2400.0 84006.6
45 2700 3.460 33.31 89930 2700.0 87229.8
50 3000 3.230 31.09 93280 3000.0 90279.8
55 3300 3.030 29.17 96254 3300.0 92954.4
60 3600 2.860 27.53 99113 3600.0 95513.4
65 3900 2.720 26.18 102117 3900.0 98216.9
70 4200 2.590 24.93 104716 4200.0 100516.0
75 4500 2.480 23.87 107431 4500.0 102930.6
80 4800 2.380 22.91 109972 4800.0 105172.0
85 5100 2.290 22.04 112427 5100.0 107326.7
90 5400 2.210 21.27 114881 5400.0 109481.5
95 5700 2.130 20.50 116874 5700.0 111174.1
100 6000 2.060 19.83 118982 6000.0 112982.3
105 6300 2.000 19.25 121293 6300.0 114992.6
110 6600 1.940 18.68 123256 6600.0 116656.4
115 6900 1.890 18.19 125538 6900.0 118637.9
120 7200 1.840 17.71 127531 7200.0 120330.5
Input Variables Results
Calculations By:
DETENTION POND CALCULATION; FAA METHOD
Project Number : 1791-003
Design Storm Required Detention Volume
Developed "C" =
Project Location : Fort Collins
Project:
Basin ID:
Depth Increment = 0.20 ft
Watershed Information Top of Micropool -- 0.00 -- -- -- 59 0.001
Selected BMP Type =EDB 4,935.20 -- 0.20 -- -- -- 252 0.006 31 0.001
Watershed Area = 11.40 acres 4,935.40 -- 0.40 -- -- -- 1,207 0.028 177 0.004
Watershed Length = 918 ft 4,935.60 -- 0.60 -- -- -- 2,898 0.067 587 0.013
Watershed Length to Centroid = 437 ft 4,935.80 -- 0.80 -- -- -- 4,949 0.114 1,372 0.032
Watershed Slope = 0.007 ft/ft 4,936.00 -- 1.00 -- -- -- 6,946 0.159 2,562 0.059
Watershed Imperviousness = 59.00% percent 4,936.20 -- 1.20 -- -- -- 8,737 0.201 4,130 0.095
Percentage Hydrologic Soil Group A = 0.0% percent 4,936.40 -- 1.40 -- -- -- 10,360 0.238 6,040 0.139
Percentage Hydrologic Soil Group B = 0.0% percent 4,936.60 -- 1.60 -- -- -- 11,778 0.270 8,253 0.189
Percentage Hydrologic Soil Groups C/D = 100.0% percent 4,936.80 -- 1.80 -- -- -- 12,763 0.293 10,708 0.246
Target WQCV Drain Time = 40.0 hours 4,937.00 -- 2.00 -- -- -- 13,662 0.314 13,350 0.306
Location for 1-hr Rainfall Depths = User Input 4,937.20 -- 2.20 -- -- -- 14,382 0.330 16,154 0.371
4,937.40 -- 2.40 -- -- -- 14,928 0.343 19,086 0.438
4,937.60 -- 2.60 -- -- -- 15,478 0.355 22,126 0.508
Optional User Overrides 4,937.80 -- 2.80 -- -- -- 16,032 0.368 25,277 0.580
Water Quality Capture Volume (WQCV) =0.025 acre-feet 0.025 acre-feet 4,938.00 -- 3.00 -- -- -- 16,590 0.381 28,539 0.655
Excess Urban Runoff Volume (EURV) = 0.645 acre-feet acre-feet 4,938.20 -- 3.20 -- -- -- 17,153 0.394 31,914 0.733
2-yr Runoff Volume (P1 = 0.82 in.) = 0.417 acre-feet 0.82 inches 4,938.40 -- 3.40 -- -- -- 17,720 0.407 35,401 0.813
5-yr Runoff Volume (P1 = 1.14 in.) = 0.657 acre-feet 1.14 inches 4,938.60 -- 3.60 -- -- -- 18,292 0.420 39,002 0.895
10-yr Runoff Volume (P1 = 1.4 in.) = 0.887 acre-feet 1.40 inches 4,938.80 -- 3.80 -- -- -- 18,868 0.433 42,718 0.981
25-yr Runoff Volume (P1 = 1.81 in.) = 1.310 acre-feet 1.81 inches 4,939.00 -- 4.00 -- -- -- 19,448 0.446 46,550 1.069
50-yr Runoff Volume (P1 = 2.27 in.) = 1.760 acre-feet 2.27 inches 4,939.20 -- 4.20 -- -- -- 20,032 0.460 50,498 1.159
100-yr Runoff Volume (P1 = 2.86 in.) = 2.372 acre-feet 2.86 inches 4,939.40 -- 4.40 -- -- -- 20,621 0.473 54,563 1.253
500-yr Runoff Volume (P1 = 4.39 in.) = 3.926 acre-feet 4.39 inches 4,939.60 -- 4.60 -- -- -- 21,214 0.487 58,746 1.349
Approximate 2-yr Detention Volume = 0.396 acre-feet 4,939.80 -- 4.80 -- -- -- 21,812 0.501 63,049 1.447
Approximate 5-yr Detention Volume = 0.629 acre-feet 4,940.00 -- 5.00 -- -- -- 22,414 0.515 67,472 1.549
Approximate 10-yr Detention Volume = 0.756 acre-feet 4,940.20 -- 5.20 -- -- -- 23,020 0.528 72,015 1.653
Approximate 25-yr Detention Volume = 0.916 acre-feet 4,940.40 -- 5.40 -- -- -- 23,631 0.542 76,680 1.760
Approximate 50-yr Detention Volume = 1.054 acre-feet 4,940.60 -- 5.60 -- -- -- 24,246 0.557 81,468 1.870
Approximate 100-yr Detention Volume = 1.315 acre-feet 4,940.80 -- 5.80 -- -- -- 24,865 0.571 86,379 1.983
4,941.00 -- 6.00 -- -- -- 25,489 0.585 91,414 2.099
Define Zones and Basin Geometry 4,941.20 -- 6.20 -- -- -- 26,117 0.600 96,575 2.217
Zone 1 Volume (WQCV) = 0.025 acre-feet 4,941.40 -- 6.40 -- -- -- 26,749 0.614 101,861 2.338
Zone 2 Volume (User Defined - Zone 1) = 2.760 acre-feet 4,941.60 -- 6.60 -- -- -- 27,386 0.629 107,275 2.463
Select Zone 3 Storage Volume (Optional) = acre-feet 4,941.80 -- 6.80 -- -- -- 28,027 0.643 112,816 2.590
Total Detention Basin Volume = 2.785 acre-feet 4,942.00 -- 7.00 -- -- -- 28,672 0.658 118,486 2.720
Initial Surcharge Volume (ISV) = user ft 3 4,942.20 -- 7.20 -- -- -- 31,444 0.722 124,498 2.858
Initial Surcharge Depth (ISD) = user ft -- -- -- --
Total Available Detention Depth (Htotal) = user ft -- -- -- --
Depth of Trickle Channel (HTC) = user ft -- -- -- --
Slope of Trickle Channel (STC) = user ft/ft -- -- -- --
Slopes of Main Basin Sides (Smain) = user H:V -- -- -- --
Basin Length-to-Width Ratio (RL/W) = user -- -- -- --
-- -- -- --
Initial Surcharge Area (AISV) =user ft 2 -- -- -- --
Surcharge Volume Length (LISV) =user ft -- -- -- --
Surcharge Volume Width (WISV) =user ft -- -- -- --
Depth of Basin Floor (HFLOOR) =user ft -- -- -- --
Length of Basin Floor (LFLOOR) =user ft -- -- -- --
Width of Basin Floor (WFLOOR) =user ft -- -- -- --
Area of Basin Floor (AFLOOR) =user ft 2 -- -- -- --
Volume of Basin Floor (VFLOOR) =user ft 3 -- -- -- --
Depth of Main Basin (HMAIN) =user ft -- -- -- --
Length of Main Basin (LMAIN) =user ft -- -- -- --
Width of Main Basin (WMAIN) =user ft -- -- -- --
Area of Main Basin (AMAIN) =user ft 2 -- -- -- --
Volume of Main Basin (VMAIN) =user ft 3 -- -- -- --
Calculated Total Basin Volume (Vtotal) =user acre-feet -- -- -- --
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DETENTION BASIN STAGE-STORAGE TABLE BUILDER
Optional
Override
Area (ft 2)
Length
(ft)
Optional
Override
Stage (ft)
Stage
(ft)
Stage - Storage
Description
Area
(ft 2)
Width
(ft)
Landing at Lemay
Pond 2
MHFD-Detention, Version 4.06 (July 2022)
Volume
(ft 3)
Volume
(ac-ft)
Area
(acre)
After providing required inputs above including 1-hour rainfall
depths, click 'Run CUHP' to generate runoff hydrographs using
the embedded Colorado Urban Hydrograph Procedure.
ExampleZone Configuration (Retention Pond)
MHFD-Detention_v4-06 - Pond 2, Basin 3/5/2024, 11:19 AM
1 User Defined Stage-Area Booleans for Message
1 Equal Stage-Area Inputs Watershed L:W
1 CountA Watershed Lc:L
Watershed Slope
0 Calc_S_TC Booleans for CUHP
1 CUHP Inputs Complete
0.73 H_FLOOR 1 CUHP Results Calculated
L_FLOOR_OTHER
0.00 ISV 0.00 ISV
0.00 Floor 0.00 Floor
0.74 Zone 1 (WQCV) 0.74 Zone 1 (WQCV)
7.10 Zone 2 (User) 7.10 Zone 2 (User)
0.00 Zone 3 0.00 Zone 3
DETENTION BASIN STAGE-STORAGE TABLE BUILDER
MHFD-Detention, Version 4.06 (July 2022)
0.000
0.715
1.430
2.145
2.860
0.000
0.185
0.370
0.555
0.740
0.00 2.00 4.00 6.00 8.00
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Stage (ft.)
Area (acres)Volume (ac-ft)
0
7900
15800
23700
31600
0
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20
0.00 2.00 4.00 6.00 8.00
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Stage (ft)
Length (ft)Width (ft)Area (sq.ft.)
MHFD-Detention_v4-06 - Pond 2, Basin 3/5/2024, 11:19 AM
Project:
Basin ID:
Estimated Estimated
Stage (ft) Volume (ac-ft) Outlet Type
Zone 1 (WQCV) 0.74 0.025 Orifice Plate
Zone 2 (User) 7.10 2.760 Weir&Pipe (Circular)
Zone 3 Not Utilized
Total (all zones) 2.785
User Input: Orifice at Underdrain Outlet (typically used to drain WQCV in a Filtration BMP)Calculated Parameters for Underdrain
Underdrain Orifice Invert Depth = N/A ft (distance below the filtration media surface) Underdrain Orifice Area = N/A ft2
Underdrain Orifice Diameter = N/A inches Underdrain Orifice Centroid = N/A feet
User Input: Orifice Plate with one or more orifices or Elliptical Slot Weir (typically used to drain WQCV and/or EURV in a sedimentation BMP)Calculated Parameters for Plate
Centroid of Lowest Orifice = 0.00 ft (relative to basin bottom at Stage = 0 ft) WQ Orifice Area per Row =N/A ft2
Depth at top of Zone using Orifice Plate = 0.74 ft (relative to basin bottom at Stage = 0 ft) Elliptical Half-Width = N/A feet
Orifice Plate: Orifice Vertical Spacing = N/A inches Elliptical Slot Centroid = N/A feet
Orifice Plate: Orifice Area per Row = N/A sq. inches Elliptical Slot Area = N/A ft2
User Input: Stage and Total Area of Each Orifice Row (numbered from lowest to highest)
Row 1 (required) Row 2 (optional) Row 3 (optional) Row 4 (optional) Row 5 (optional) Row 6 (optional) Row 7 (optional) Row 8 (optional)
Stage of Orifice Centroid (ft) 0.00 0.30 0.60
Orifice Area (sq. inches) 0.78 0.99 0.99
Row 9 (optional) Row 10 (optional) Row 11 (optional) Row 12 (optional) Row 13 (optional) Row 14 (optional) Row 15 (optional) Row 16 (optional)
Stage of Orifice Centroid (ft)
Orifice Area (sq. inches)
User Input: Vertical Orifice (Circular or Rectangular)Calculated Parameters for Vertical Orifice
Not Selected Not Selected Not Selected Not Selected
Invert of Vertical Orifice = N/A N/A ft (relative to basin bottom at Stage = 0 ft) Vertical Orifice Area =N/A N/A ft2
Depth at top of Zone using Vertical Orifice = N/A N/A ft (relative to basin bottom at Stage = 0 ft) Vertical Orifice Centroid = N/A N/A feet
Vertical Orifice Diameter = N/A N/A inches
User Input: Overflow Weir (Dropbox with Flat or Sloped Grate and Outlet Pipe OR Rectangular/Trapezoidal Weir and No Outlet Pipe) Calculated Parameters for Overflow Weir
grate Zone 2 Weir Not Selected Zone 2 Weir Not Selected
Overflow Weir Front Edge Height, Ho = 1.00 N/A ft (relative to basin bottom at Stage = 0 ft)Height of Grate Upper Edge, Ht =1.75 N/A feet
Overflow Weir Front Edge Length = 3.00 N/A feet Overflow Weir Slope Length = 3.09 N/A feet
Overflow Weir Grate Slope = 4.00 N/A H:V Grate Open Area / 100-yr Orifice Area = 84.09 N/A
Horiz. Length of Weir Sides = 3.00 N/A feet Overflow Grate Open Area w/o Debris = 7.34 N/A ft2
Overflow Grate Type = Close Mesh Grate N/A Overflow Grate Open Area w/ Debris = 3.67 N/A ft2
Debris Clogging % = 50% N/A %
User Input: Outlet Pipe w/ Flow Restriction Plate (Circular Orifice, Restrictor Plate, or Rectangular Orifice)Calculated Parameters for Outlet Pipe w/ Flow Restriction Plate
Zone 2 Circular Not Selected Zone 2 Circular Not Selected
Depth to Invert of Outlet Pipe = 0.00 N/A ft (distance below basin bottom at Stage = 0 ft)Outlet Orifice Area = 0.09 N/A ft2
Circular Orifice Diameter = 4.00 N/A inches Outlet Orifice Centroid = 0.17 N/A feet
Half-Central Angle of Restrictor Plate on Pipe = N/A N/A radians
User Input: Emergency Spillway (Rectangular or Trapezoidal)Calculated Parameters for Spillway
Spillway Invert Stage= ft (relative to basin bottom at Stage = 0 ft) 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 Basin Volume at Top of Freeboard = acre-ft
Max Ponding Depth of Target Storage Volume =7.20 feet Discharge at Top of Freeboard = cfs
Routed Hydrograph Results
Design Storm Return Period =WQCV EURV 2 Year 5 Year 10 Year 25 Year 50 Year 100 Year 500 Year
One-Hour Rainfall Depth (in) =N/A N/A 0.82 1.14 1.40 1.81 2.27 2.86 4.39
CUHP Runoff Volume (acre-ft) =0.025 0.645 0.417 0.657 0.887 1.310 1.760 2.372 3.926
Inflow Hydrograph Volume (acre-ft) =N/A N/A 0.417 0.657 0.887 1.310 1.760 2.372 3.926
CUHP Predevelopment Peak Q (cfs) =N/A N/A 0.1 1.3 3.1 7.7 11.6 17.4 30.9
OPTIONAL Override Predevelopment Peak Q (cfs) =N/A N/A
Predevelopment Unit Peak Flow, q (cfs/acre) =N/A N/A 0.01 0.11 0.27 0.67 1.02 1.53 2.71
Peak Inflow Q (cfs) =N/A N/A 6.2 9.9 13.3 20.3 27.2 36.8 59.7
Peak Outflow Q (cfs) =0.1 0.7 0.6 0.7 0.7 0.8 0.9 1.0 1.1
Ratio Peak Outflow to Predevelopment Q =N/A N/A N/A 0.5 0.2 0.1 0.1 0.1 0.0
Structure Controlling Flow =Plate Outlet Plate 1 Outlet Plate 1 Outlet Plate 1 Outlet Plate 1 Outlet Plate 1 Outlet Plate 1 Outlet Plate 1 N/A
Max Velocity through Grate 1 (fps) =N/A 0.08 0.06 0.1 0.1 0.1 0.1 0.1 0.1
Max Velocity through Grate 2 (fps) =N/A N/A N/A N/A N/A N/A N/A N/A N/A
Time to Drain 97% of Inflow Volume (hours) =8 21 20 22 24 28 32 37 52
Time to Drain 99% of Inflow Volume (hours) =9 25 23 26 29 34 39 44 58
Maximum Ponding Depth (ft) =0.74 2.98 2.08 2.72 3.29 4.24 5.12 6.18 7.20
Area at Maximum Ponding Depth (acres) =0.10 0.38 0.32 0.36 0.40 0.46 0.52 0.60 0.72
Maximum Volume Stored (acre-ft) =0.025 0.648 0.329 0.551 0.768 1.178 1.611 2.205 2.858
The user can override the default CUHP hydrographs and runoff volumes by entering new values in the Inflow Hydrographs table (Columns W through AF).
DETENTION BASIN OUTLET STRUCTURE DESIGN
MHFD-Detention, Version 4.06 (July 2022)
Landing at Lemay
Pond 2
Example Zone Configuration (Retention Pond)
MHFD-Detention_v4-06 - Pond 2, Outlet Structure 3/5/2024, 11:19 AM
COUNTA for Basin Tab = 1 Ao Dia WQ Plate Type Vert Orifice 1Vert Orifice 2
Count_Underdrain = 0 0.11(diameter = 3/8 inch)2 1 1
Count_WQPlate = 1 0.14(diameter = 7/16 inch)
Count_VertOrifice1 = 0 0.18(diameter = 1/2 inch)Outlet Plate 1 Outlet Plate 2 Drain Time Message Boolean
Count_VertOrifice2 = 0 0.24(diameter = 9/16 inch)2 1 5yr, <72hr 0
Count_Weir1 = 1 0.29(diameter = 5/8 inch)>5yr, <120hr 0
Count_Weir2 = 0 0.36(diameter = 11/16 inch)Max Depth Row
Count_OutletPipe1 = 1 0.42(diameter = 3/4 inch)WQCV 75
Count_OutletPipe2 = 0 0.50(diameter = 13/16 inch)2 Year 209
COUNTA_2 (Standard FSD Setup)= 1 0.58(diameter = 7/8 inch)EURV 299
Hidden Parameters & Calculations 0.67(diameter = 15/16 inch)5 Year 273
MaxPondDepth_Error? FALSE 0.76 (diameter = 1 inch)10 Year 330 Spillway Depth
Cd_Broad-Crested Weir 3.00 0.86(diameter = 1-1/16 inches)25 Year 425
WQ Plate Flow at 100yr depth = 0.22 0.97(diameter = 1-1/8 inches)50 Year 513
CLOG #1= 50% 1.08(diameter = 1-3/16 inches)100 Year 619 1 Z1_Boolean
n*Cdw #1 = 0.44 1.20(diameter = 1-1/4 inches)500 Year 721 1 Z2_Boolean
n*Cdo #1 = 1.83 1.32(diameter = 1-5/16 inches)Zone3_Pulldown Message 1 Z3_Boolean
Overflow Weir #1 Angle = 0.245 1.45(diameter = 1-3/8 inches)1 Opening Message
CLOG #2= N/A 1.59(diameter = 1-7/16 inches)Draintime Running
n*Cdw #2 = N/A 1.73(diameter = 1-1/2 inches)Outlet Boolean Outlet Rank Total (1 to 4)
n*Cdo #2 = N/A 1.88(diameter = 1-9/16 inches)Vertical Orifice 1 0 0
1
Overflow Weir #2 Angle = N/A 2.03(diameter = 1-5/8 inches)Vertical Orifice 2 0 0 Boolean
Underdrain Q at 100yr depth = 0.00 2.20(diameter = 1-11/16 inches)Overflow Weir 1 1 1 0 Max Depth
VertOrifice1 Q at 100yr depth = 0.00 2.36(diameter = 1-3/4 inches)Overflow Weir 2 0 0 0 500yr Depth
VertOrifice2 Q at 100yr depth = 0.00 2.54(diameter = 1-13/16 inches)Outlet Pipe 1 1 1 1 Freeboard
2.72(diameter = 1-7/8 inches)Outlet Pipe 2 0 0 0 Spillway
Count_User_Hydrographs 0 2.90(diameter = 1-15/16 inches)0 Spillway Length
CountA_3 (EURV & 100yr) = 1 3.09(diameter = 2 inches)FALSE Time Interval
CountA_4 (100yr Only) = 1 3.29(use rectangular openings)Button Visibility Boolean
COUNTA_5 (FSD Weir Only)= 0 0 WQCV Underdrain
COUNTA_6 (EURV Weir Only)= 1 1 WQCV Plate
0 EURV-WQCV Plate
Outlet1_Pulldown_Boolean 0 EURV-WQCV VertOriice
Outlet2_Pulldown_Boolean 0 Outlet 90% Qpeak
Outlet3_Pulldown_Boolean 1 Outlet Undetained
0 Weir Only 90% Qpeak
0 Five Year Ratio Plate
0 Five Year Ratio VertOrifice
EURV_draintime_user
Spillway Options
Offset
Overlapping
S-A-V-D Chart Axis Default X-axis Left Y-Axis Right Y-Axis
minimum bound 0.00 0 0
maximum bound 8.00 130,000 10
S-A-V-D Chart Axis Override X-axis Left Y-Axis Right Y-Axis
minimum bound
maximum bound
MHFD-Detention, Version 4.06 (July 2022)
DETENTION BASIN OUTLET STRUCTURE DESIGN
0
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500YR IN
500YR OUT
100YR IN
100YR OUT
50YR IN
50YR OUT
25YR IN
25YR OUT
10YR IN
10YR OUT
5YR IN
5YR OUT
2YR IN
2YR OUT
EURV IN
EURV OUT
WQCV IN
WQCV OUT
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DRAIN TIME [hr]
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100YR
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25YR
10YR
5YR
2YR
EURV
WQCV
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PONDING DEPTH [ft]
User Area [ft^2]
Interpolated Area [ft^2]
Summary Area [ft^2]
Volume [ft^3]
Summary Volume [ft^3]
Outflow [cfs]
Summary Outflow [cfs]
MHFD-Detention_v4-06 - Pond 2, Outlet Structure 3/5/2024, 11:19 AM
STORM SEWERS
Storm 3-2
RG Inlets
Storm 3-2
Storm 3-2
Storm 3-2
Storm 1
Pond 2
Outlet
Structure
Pond 1
Overflow
Inlet
Storm 1
Storm 1
Type-R
Inlets on
Cordova
RG Inlet
Area Inlets
Culvert Crossing: Storm 7
Culvert Summary Table - Storm 7
Discharge
Names
Total
Discharge
(cfs)
Culvert
Discharge
(cfs)
Headwater
Elevation
(ft)
Inlet
Control
Depth(ft)
Outlet
Control
Depth(ft)
Flow
Type
Normal
Depth
(ft)
Critical
Depth
(ft)
Outlet
Depth
(ft)
Tailwater
Depth
(ft)
Outlet
Velocity
(ft/s)
Tailwater
Velocity
(ft/s)
Q2 0.71 0.71 4943.61 0.47 0.20 1-S2n 0.32 0.33 0.32 0.14 2.88 1.92
Q100 3.08 3.08 4944.33 1.07 1.19 2-
M2c
0.71 0.71 0.71 0.32 4.31 2.98
Crossing Summary Table
Headwater
Elevation
(ft)
Discharge
Names
Total
Discharge
(cfs)
Storm 7
Discharge
(cfs)
Roadway
Discharge
(cfs)
Iterations
4943.61 Q2 0.71 0.71 0.00 1
4944.33 Q100 3.08 3.08 0.00 1
4946.10 Overtopping 8.09 8.09 0.00 Overtopping
INLETS
INLET SUMMARY
Inlet Design
Point
Contributing
Basin/Area Inlet Type Inlet Size
Q2 Flow
(cfs)
Inlet
Capacity
(cfs)
Q100 Flow
Intercepted
(cfs)
Q100 Flow Not
Intercepted
(cfs)
Notes
1-2 c Pond 1 Type-C 3' x 3' n/a -- 2.5 -- Pond 1 Release Rate (2.5 cfs)
3-4 d Basin D Type-C 3' x 3' 3.22 -- 14.03 --
3-5 m Basin M Type-C 3' x 3' 5.77 -- 24.57 --
4-1 j Basin J/K Type-R 5' 1.85 -- 8.06 --
Inlet modeled with combined flows from Basins J & K; in ultimate
condition, an additional inlet will be installed on the east side of
Cordova Rd. for Basin K
5-2.1 a Basin A Type-C 3' x 3' 4.53 -- 19.75 --
6-8 b Basin B Type-C 3' x 3' 3.4 -- 14.65 --
8-4 e Basin E Type-R 5' 7.61 5.4 9.3 24.41
Basin E WQ flows are captured by inlet and routed to chambers.
Basin E Q100 is 29.81 cfs; Interception is limited to inlet/chambers
capacity (5.4 cfs); remaining 24.42 cfs of Q100 overtops walk directly
into Pond 1
9-1 c Basin C Type-R 3' x 3' 5.68 5.4 5.4 19.38
Basin C WQ flows are captured by inlet and routed to chambers.
Basin C Q100 is 24.78 cfs; Interception limited to inlet/chambers
capacity (9.3 cfs); remaining 15.48 cfs of Q100 overtops walk directly
into Pond 2
Area Inlet(s) around
Building 1 Area Inlet 8" Dome N/A -- 0.94 --
Area Inlet(s) around
Building 3 Area Inlet 8" Dome N/A -- 0.94 --
Area Inlet(s) around
Building 4 Area Inlet 8" Dome N/A -- 0.94 --
Area Inlet(s) around
Building 5 Area Inlet 8" Dome N/A -- 0.94 --
Area Inlet(s) around
Building 8 Area Inlet 8" Dome N/A -- 0.94 --
Area Inlet(s) around
Building 9 Area Inlet 8" Dome N/A -- 0.94 --
Area Inlet(s) around
Building 14 Area Inlet 8" Dome N/A -- 0.94 --
Area Inlet(s) around
Building 17 Area Inlet 8" Dome N/A -- 0.94 --
Area Inlet(s) around
Clubhouse Area Inlet 8" Dome N/A -- 0.94 --
n/a
8" Dome capacity @ 1' of depth. Area inlet + pipe capacities are for
drainage only; total flows are assigned at design points for primary
pipe sizing.
n/a
MHFD-Inlet, Version 5.02 (August 2022)
Worksheet Protected
INLET NAME Inlet 4-1 Inlet 8-4 Inlet 9-1 User-Defined
Site Type (Urban or Rural) URBAN URBAN URBAN
Inlet Application (Street or Area) STREET STREET STREET
Hydraulic Condition In Sump In Sump In Sump
Inlet Type CDOT Type R Curb Opening CDOT Type R Curb Opening CDOT Type R Curb Opening
USER-DEFINED INPUT
User-Defined Design Flows
Minor QKnown (cfs)1.9 7.6 5.7
Major QKnown (cfs)8.1 29.8 24.8
Bypass (Carry-Over) Flow from Upstream Inlets must be organized from upstream (left) to downstream (right) in order for bypass flows to be linked.
Receive Bypass Flow from: No Bypass Flow Received No Bypass Flow Received No Bypass Flow Received
Minor Bypass Flow Received, Qb (cfs)0.0 0.0 0.0
Major Bypass Flow Received, Qb (cfs)0.0 0.0 0.0
Watershed Characteristics
Subcatchment Area (acres)
Percent Impervious
NRCS Soil Type
Watershed Profile
Overland Slope (ft/ft)
Overland Length (ft)
Channel Slope (ft/ft)
Channel Length (ft)
Minor Storm Rainfall Input
Design Storm Return Period, Tr (years)
One-Hour Precipitation, P1 (inches)
Major Storm Rainfall Input
Design Storm Return Period, Tr (years)
One-Hour Precipitation, P1 (inches)
CALCULATED OUTPUT
Minor Total Design Peak Flow, Q (cfs) 1.9 7.6 5.7
Major Total Design Peak Flow, Q (cfs) 8.1 29.8 24.8
Minor Flow Bypassed Downstream, Qb (cfs)N/A N/A N/A
Major Flow Bypassed Downstream, Qb (cfs)N/A N/A N/A
INLET MANAGEMENT
Project:
Inlet ID:
Gutter Geometry:
Maximum Allowable Width for Spread Behind Curb TBACK =15.0 ft
Side Slope Behind Curb (leave blank for no conveyance credit behind curb)SBACK =0.020 ft/ft
Manning's Roughness Behind Curb (typically between 0.012 and 0.020)nBACK =0.012
Height of Curb at Gutter Flow Line HCURB =6.00 inches
Distance from Curb Face to Street Crown TCROWN =23.0 ft
Gutter Width W =2.00 ft
Street Transverse Slope SX =0.022 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 =23.0 23.0
ft
Max. Allowable Depth at Gutter Flowline for Minor & Major Storm dMAX =6.0 12.0
inches
Check boxes are not applicable in SUMP conditions
MINOR STORM Allowable Capacity is not applicable to Sump Condition Minor Storm Major Storm
MAJOR STORM Allowable Capacity is not applicable to Sump Condition Qallow =SUMP SUMP cfs
MHFD-Inlet, Version 5.02 (August 2022)
ALLOWABLE CAPACITY FOR ONE-HALF OF STREET (Minor & Major Storm)
(Based on Regulated Criteria for Maximum Allowable Flow Depth and Spread)
Landing at Lemay
Inlet 4-1
1
Design Information (Input)MINOR MAJOR
Type of Inlet Type =
Local Depression (additional to continuous gutter depression 'a' from above)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 7.5 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
Open Area 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 2.3-3.7)Cw (C) =3.60 3.60
Curb Opening Orifice Coefficient (typical value 0.60 - 0.70)Co (C) =0.67 0.67
Low Head Performance Reduction (Calculated)MINOR MAJOR
Depth for Grate Midwidth dGrate =N/A N/A ft
Depth for Curb Opening Weir Equation dCurb =0.33 0.46 ft
Grated Inlet Performance Reduction Factor for Long Inlets RFGrate =N/A N/A
Curb Opening Performance Reduction Factor for Long Inlets RFCurb =1.00 1.00
Combination Inlet Performance Reduction Factor for Long Inlets RFCombination =N/A N/A
MINOR MAJOR
Total Inlet Interception Capacity (assumes clogged condition)Qa =5.4 8.6 cfs
Inlet Capacity IS GOOD for Minor and Major Storms (>Q Peak)Q PEAK REQUIRED =1.9 8.1 cfs
INLET IN A SUMP OR SAG LOCATION
MHFD-Inlet, Version 5.02 (August 2022)
CDOT Type R Curb Opening
H-VertH-Curb
W
Lo (C)
Lo (G)
Wo
WP
CDOT Type R Curb Opening
Override Depths
1
Project:
Inlet ID:
Gutter Geometry:
Maximum Allowable Width for Spread Behind Curb TBACK =25.0 ft
Side Slope Behind Curb (leave blank for no conveyance credit behind curb)SBACK =0.060 ft/ft
Manning's Roughness Behind Curb (typically between 0.012 and 0.020)nBACK =0.012
Height of Curb at Gutter Flow Line HCURB =6.00 inches
Distance from Curb Face to Street Crown TCROWN =41.0 ft
Gutter Width W =2.00 ft
Street Transverse Slope SX =0.020 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 =41.0 41.0
ft
Max. Allowable Depth at Gutter Flowline for Minor & Major Storm dMAX =6.0 8.0
inches
Check boxes are not applicable in SUMP conditions
MINOR STORM Allowable Capacity is not applicable to Sump Condition Minor Storm Major Storm
MAJOR STORM Allowable Capacity is not applicable to Sump Condition Qallow =SUMP SUMP cfs
MHFD-Inlet, Version 5.02 (August 2022)
ALLOWABLE CAPACITY FOR ONE-HALF OF STREET (Minor & Major Storm)
(Based on Regulated Criteria for Maximum Allowable Flow Depth and Spread)
Landing at Lemay
Inlet 8-4
1
Design Information (Input)MINOR MAJOR
Type of Inlet Type =
Local Depression (additional to continuous gutter depression 'a' from above)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 8.0 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
Open Area 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 2.3-3.7)Cw (C) =3.60 3.60
Curb Opening Orifice Coefficient (typical value 0.60 - 0.70)Co (C) =0.67 0.67
Low Head Performance Reduction (Calculated)MINOR MAJOR
Depth for Grate Midwidth dGrate =N/A N/A ft
Depth for Curb Opening Weir Equation dCurb =0.33 0.50 ft
Grated Inlet Performance Reduction Factor for Long Inlets RFGrate =N/A N/A
Curb Opening Performance Reduction Factor for Long Inlets RFCurb =1.00 1.00
Combination Inlet Performance Reduction Factor for Long Inlets RFCombination =N/A N/A
MINOR MAJOR
Total Inlet Interception Capacity (assumes clogged condition)Qa =5.4 9.3 cfs
WARNING: Inlet Capacity < Q Peak for Minor and Major Storms Q PEAK REQUIRED =7.6 29.8 cfs
CDOT Type R Curb Opening
INLET IN A SUMP OR SAG LOCATION
MHFD-Inlet, Version 5.02 (August 2022)
H-VertH-Curb
W
Lo (C)
Lo (G)
Wo
WP
CDOT Type R Curb Opening
Override Depths
1
Only need to pass the WQ
event through this inlet
Project:
Inlet ID:
Gutter Geometry:
Maximum Allowable Width for Spread Behind Curb TBACK =1.0 ft
Side Slope Behind Curb (leave blank for no conveyance credit behind curb)SBACK =0.000 ft/ft
Manning's Roughness Behind Curb (typically between 0.012 and 0.020)nBACK =0.012
Height of Curb at Gutter Flow Line HCURB =6.00 inches
Distance from Curb Face to Street Crown TCROWN =62.0 ft
Gutter Width W =2.00 ft
Street Transverse Slope SX =0.008 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 =62.0 62.0
ft
Max. Allowable Depth at Gutter Flowline for Minor & Major Storm dMAX =6.0 6.0
inches
Check boxes are not applicable in SUMP conditions
MINOR STORM Allowable Capacity is not applicable to Sump Condition Minor Storm Major Storm
MAJOR STORM Allowable Capacity is not applicable to Sump Condition Qallow =SUMP SUMP cfs
MHFD-Inlet, Version 5.02 (August 2022)
ALLOWABLE CAPACITY FOR ONE-HALF OF STREET (Minor & Major Storm)
(Based on Regulated Criteria for Maximum Allowable Flow Depth and Spread)
Landing at Lemay
Inlet 9-1
1
Design Information (Input)MINOR MAJOR
Type of Inlet Type =
Local Depression (additional to continuous gutter depression 'a' from above)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
Open Area 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 2.3-3.7)Cw (C) =3.60 3.60
Curb Opening Orifice Coefficient (typical value 0.60 - 0.70)Co (C) =0.67 0.67
Low Head Performance Reduction (Calculated)MINOR MAJOR
Depth for Grate Midwidth dGrate =N/A N/A ft
Depth for Curb Opening Weir Equation dCurb =0.33 0.33 ft
Grated Inlet Performance Reduction Factor for Long Inlets RFGrate =N/A N/A
Curb Opening Performance Reduction Factor for Long Inlets RFCurb =1.00 1.00
Combination Inlet Performance Reduction Factor for Long Inlets RFCombination =N/A N/A
MINOR MAJOR
Total Inlet Interception Capacity (assumes clogged condition)Qa =5.4 5.4 cfs
WARNING: Inlet Capacity < Q Peak for Minor and Major Storms Q PEAK REQUIRED =5.7 24.8 cfs
CDOT Type R Curb Opening
INLET IN A SUMP OR SAG LOCATION
MHFD-Inlet, Version 5.02 (August 2022)
H-VertH-Curb
W
Lo (C)
Lo (G)
Wo
WP
CDOT Type R Curb Opening
Override Depths
1
Only need to pass the WQ
event through this inlet
Inlet Name: 1-2 Project:
2-Year Design Flow (cfs) 2.50 Location:
100-Year Design Flow (cfs) 2.50 Calc. By:
Type of Grate: 9.00
Length of Grate (ft): 3.0 4,941.10
Width of Grate (ft): 3.0 0.50
Depth Above Inlet (ft)Elevation
(ft)
Shallow Weir
Flow (cfs)
Orifice Flow
(cfs)
Actual Flow
(cfs)Notes
0.00 4,941.10 0.00 0.00 0.00
0.20 4,941.30 1.61 10.82 1.61 Pond 1 Release Rate interpolated at 0.26';
0.40 4,941.50 4.55 15.30 4.55 0.3' of depth available before Pond 2 spill
0.60 4,941.70 8.37 18.73 8.37 at 4941.4'.
0.80 4,941.90 12.88 21.63 12.88
1.00 4,942.10 18.00 24.18 18.00
1.20 4,942.30 23.66 26.49 23.66
1.40 4,942.50 29.82 28.61 29.82
1.60 4,942.70 36.43 30.59 36.43
1.80 4,942.90 43.47 32.45 32.45
2.00 4,943.10 50.91 34.20 34.20
AREA INLET PERFORMANCE CURVE
Governing Equations
If H > 1.792 (A/P), then the grate operates like an orifice; otherwise it operates like a weir.
Input Parameters
Rim Elevation (ft):
Open Area of Grate (ft2):
Depth vs. Flow
Fabricated
1791-003
Landing
A. Snow
Reduction Factor:
0.00
10.00
20.00
30.00
40.00
50.00
60.00
0.00 0.50 1.00 1.50 2.00 2.50
Di
s
c
h
a
r
g
e
(
c
f
s
)
Stage (ft)
Stage - Discharge Curves
Series1
Series2
At low flow dephs, the inlet will act like a weir governed by the following equation:
* where P = 2(L + W)
* where H corresponds to the depth of water above the flowline
At higher flow depths, the inlet will act like an orifice governed by the following equation:
* where A equals the open area of the inlet grate
* where H corresponds to the depth of water above the centroid of the cross-sectional area
(A).
= 3.0
.
= 0.67 (2 ) .
Inlet Name:3-4 Project:
2-Year Design Flow (cfs)3.29 Location:
100-Year Design Flow (cfs)14.35 Calc. By:
Type of Grate: 9.00
Length of Grate (ft):3.0 4,942.10
Width of Grate (ft):3.0 0.50
Depth Above Inlet (ft)Elevation
(ft)
Shallow Weir
Flow (cfs)
Orifice Flow
(cfs)
Actual Flow
(cfs)Notes
0.00 4,942.10 0.00 0.00 0.00
0.10 4,942.20 0.57 7.65 0.57
0.20 4,942.30 1.61 10.82 1.61
0.30 4,942.40 2.96 13.25 2.96
0.40 4,942.50 4.55 15.30 4.55
0.50 4,942.60 6.36 17.10 6.36
0.60 4,942.70 8.37 18.73 8.37
0.70 4,942.80 10.54 20.23 10.54
0.80 4,942.90 12.88 21.63 12.88
0.90 4,943.00 15.37 22.94 15.37 100-yr flow interpolated at 0.86'
1.00 4,943.10 18.00 24.18 18.00
AREA INLET PERFORMANCE CURVE
Governing Equations
If H > 1.792 (A/P), then the grate operates like an orifice; otherwise it operates like a weir.
Input Parameters
Rim Elevation (ft):
Open Area of Grate (ft 2):
Depth vs. Flow
Fabricated
1791-003
Landing
A. Snow
Reduction Factor:
0.00
5.00
10.00
15.00
20.00
25.00
30.00
0.00 0.20 0.40 0.60 0.80 1.00 1.20
Di
s
c
h
a
r
g
e
(
c
f
s
)
Stage (ft)
Stage - Discharge Curves
Series1
Series2
Atlow flow dephs, the inlet will act like a weir governed by the following equation:
* where P = 2(L + W)
* where H corresponds to the depth of water above the flowline
At higher flow depths, the inlet will act like an orifice governed by the following equation:
* where A equals the open area of the inlet grate
* where H corresponds to the depth of water above the centroid of the cross-sectional area (A).
= 3.0
.
= 0.67 (2 ) .
Inlet Name:3-5 Project:
2-Year Design Flow (cfs)6.08 Location:
100-Year Design Flow (cfs)26.54 Calc. By:
Type of Grate: 9.00
Length of Grate (ft):3.0 4,943.75
Width of Grate (ft):3.0 0.50
Depth Above Inlet (ft)Elevation
(ft)
Shallow Weir
Flow (cfs)
Orifice Flow
(cfs)
Actual Flow
(cfs)Notes
0.00 4,943.75 0.00 0.00 0.00
0.20 4,943.95 1.61 10.82 1.61
0.40 4,944.15 4.55 15.30 4.55
0.60 4,944.35 8.37 18.73 8.37
0.80 4,944.55 12.88 21.63 12.88
1.00 4,944.75 18.00 24.18 18.00
1.20 4,944.95 23.66 26.49 23.66
1.40 4,945.15 29.82 28.61 29.82 100-yr flow interpolated at 1.29'
1.60 4,945.35 36.43 30.59 36.43
1.80 4,945.55 43.47 32.45 32.45
2.00 4,945.75 50.91 34.20 34.20
AREA INLET PERFORMANCE CURVE
Governing Equations
If H > 1.792 (A/P), then the grate operates like an orifice; otherwise it operates like a weir.
Input Parameters
Rim Elevation (ft):
Open Area of Grate (ft 2):
Depth vs. Flow
Fabricated
1791-003
Landing
A. Snow
Reduction Factor:
0.00
10.00
20.00
30.00
40.00
50.00
60.00
0.00 0.50 1.00 1.50 2.00 2.50
Di
s
c
h
a
r
g
e
(
c
f
s
)
Stage (ft)
Stage - Discharge Curves
Series1
Series2
Atlow flow dephs, the inlet will act like a weir governed by the following equation:
* where P = 2(L + W)
* where H corresponds to the depth of water above the flowline
At higher flow depths, the inlet will act like an orifice governed by the following equation:
* where A equals the open area of the inlet grate
* where H corresponds to the depth of water above the centroid of the cross-sectional area (A).
= 3.0
.
= 0.67 (2 ) .
Inlet Name:5-2.1 Project:
2-Year Design Flow (cfs)4.52 Location:
100-Year Design Flow (cfs)19.73 Calc. By:
Type of Grate: 9.00
Length of Grate (ft):3.0 4,944.50
Width of Grate (ft):3.0 0.50
Depth Above Inlet (ft)Elevation
(ft)
Shallow Weir
Flow (cfs)
Orifice Flow
(cfs)
Actual Flow
(cfs)Notes
0.00 4,944.50 0.00 0.00 0.00
0.20 4,944.70 1.61 10.82 1.61
0.40 4,944.90 4.55 15.30 4.55
0.60 4,945.10 8.37 18.73 8.37
0.80 4,945.30 12.88 21.63 12.88
1.00 4,945.50 18.00 24.18 18.00
1.20 4,945.70 23.66 26.49 23.66 100-yr flow interpolated at 1.06'
1.40 4,945.90 29.82 28.61 29.82
1.60 4,946.10 36.43 30.59 36.43
1.80 4,946.30 43.47 32.45 32.45
2.00 4,946.50 50.91 34.20 34.20
AREA INLET PERFORMANCE CURVE
Governing Equations
If H > 1.792 (A/P), then the grate operates like an orifice; otherwise it operates like a weir.
Input Parameters
Rim Elevation (ft):
Open Area of Grate (ft2):
Depth vs. Flow
Fabricated
1791-003
Landing
A. Snow
Reduction Factor:
0.00
10.00
20.00
30.00
40.00
50.00
60.00
0.00 0.50 1.00 1.50 2.00 2.50
Di
s
c
h
a
r
g
e
(
c
f
s
)
Stage (ft)
Stage - Discharge Curves
Series1
Series2
At low flow dephs, the inlet will act like a weir governed by the following equation:
* where P = 2(L + W)
* where H corresponds to the depth of water above the flowline
At higher flow depths, the inlet will act like an orifice governed by the following equation:
* where A equals the open area of the inlet grate
* where H corresponds to the depth of water above the centroid of the cross-sectional area
(A).
= 3.0
.
= 0.67 (2 ) .
Inlet Name:6-8 Project:
2-Year Design Flow (cfs)3.40 Location:
100-Year Design Flow (cfs)14.65 Calc. By:
Type of Grate: 9.00
Length of Grate (ft):3.0 4,944.50
Width of Grate (ft):3.0 0.50
Depth Above Inlet (ft)Elevation
(ft)
Shallow Weir
Flow (cfs)
Orifice Flow
(cfs)
Actual Flow
(cfs)Notes
0.00 4,944.50 0.00 0.00 0.00
0.20 4,944.70 1.61 10.82 1.61
0.40 4,944.90 4.55 15.30 4.55
0.60 4,945.10 8.37 18.73 8.37
0.80 4,945.30 12.88 21.63 12.88
1.00 4,945.50 18.00 24.18 18.00 100-yr flow interpolated at 0.87'
1.20 4,945.70 23.66 26.49 23.66
1.40 4,945.90 29.82 28.61 29.82
1.60 4,946.10 36.43 30.59 36.43
1.80 4,946.30 43.47 32.45 32.45
2.00 4,946.50 50.91 34.20 34.20
AREA INLET PERFORMANCE CURVE
Governing Equations
If H > 1.792 (A/P), then the grate operates like an orifice; otherwise it operates like a weir.
Input Parameters
Rim Elevation (ft):
Open Area of Grate (ft2):
Depth vs. Flow
Fabricated
1791-003
Landing
A. Snow
Reduction Factor:
0.00
10.00
20.00
30.00
40.00
50.00
60.00
0.00 0.50 1.00 1.50 2.00 2.50
Di
s
c
h
a
r
g
e
(
c
f
s
)
Stage (ft)
Stage - Discharge Curves
Series1
Series2
At low flow dephs, the inlet will act like a weir governed by the following equation:
* where P = 2(L + W)
* where H corresponds to the depth of water above the flowline
At higher flow depths, the inlet will act like an orifice governed by the following equation:
* where A equals the open area of the inlet grate
* where H corresponds to the depth of water above the centroid of the cross-sectional area
(A).
= 3.0
.
= 0.67 (2 ) .
Inlet Name: Area Inlets Project:
10-Year Design Flow (cfs) n/a Location:
100-Year Design Flow (cfs) n/a Calc. By:
Type of Grate: 0.35
Diameter of Grate (ft): 0.67 Varies
0.50
Shallow Weir
Flow (cfs)
Orifice Flow
(cfs)
Actual Flow
(cfs)Notes
0.00 0.00 0.00
0.10 0.30 0.10
0.28 0.42 0.28
0.52 0.51 0.51
0.79 0.59 0.59
1.11 0.66 0.66
1.46 0.73 0.73
1.84 0.78 0.78
2.25 0.84 0.84
2.68 0.89 0.89
3.14 0.94 0.94
5.77 1.15 1.15
Depth vs. Flow
Nyloplast 8" Dome
1791-003
Landing at Lemay
A. Snow
Reduction Factor:
AREA INLET PERFORMANCE CURVE
Governing Equations
If H > 1.792 (A/P), then the grate operates like an orifice; otherwise it operates like a weir.
Input Parameters
Rim Elevation (ft.):
Open Area of Grate (ft 2):
Depth Above Inlet (ft)
0.00
0.10
0.20
0.30
0.90
1.00
1.50
0.40
0.50
0.60
0.70
0.80
0.00
1.00
2.00
3.00
4.00
5.00
6.00
7.00
0.00 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60
Di
s
c
h
a
r
g
e
(
c
f
s
)
Stage (ft)
Stage - Discharge Curves
Series1
Series2
Atlow flow dephs, the inlet will act like a weir governed by the following equation:
* where P = π* Dia. of grate
* where H corresponds to the depth of water above the flowline
At higher flow depths, the inlet will act like an orifice governed by the following
equation:
* where A equals the open area of teh inlet grate
* where H corresponds to the depth of water above the centroid of the cross-sectional
= 3.0
.
= 0.67 (2 ) .
SWALES
Channel Report
Hydraflow Express Extension for Autodesk® Civil 3D® by Autodesk, Inc. Tuesday, Sep 26 2023
West Swale/Trickle Channel
Trapezoidal
Bottom Width (ft) = 2.00
Side Slopes (z:1) = 3.00, 10.00
Total Depth (ft) = 2.00
Invert Elev (ft) = 4943.00
Slope (%) = 0.50
N-Value = 0.013
Calculations
Compute by: Known Q
Known Q (cfs) = 3.08
Highlighted
Depth (ft) = 0.30
Q (cfs) = 3.080
Area (sqft) = 1.19
Velocity (ft/s) = 2.60
Wetted Perim (ft) = 5.96
Crit Depth, Yc (ft) = 0.31
Top Width (ft) = 5.90
EGL (ft) = 0.41
0 5 10 15 20 25 30 35 40
Elev (ft) Depth (ft)Section
4942.50 -0.50
4943.00 0.00
4943.50 0.50
4944.00 1.00
4944.50 1.50
4945.00 2.00
4945.50 2.50
4946.00 3.00
Reach (ft)
SCOURSTOP SUMMARY
Project:
Project Location:
Calculations By:
Date:
Forebay/ Rain
Garden Basin WQCV (ft
3)
Forebay Design
Volume (ft3)Forebay Depth Forebay Length Forebay Width Forebay Area
Basin Q100 (cfs)Release (cfs) Pipe Size
as calculated/shown in LID Summary Table 1% of WQCV (ft) (ft) (ft)
(ft2)see hydrology tables 2% of Q100 (in)
A 1600 16 1 4.5 4 18 19.73 0.39 3.5
B 1398 13.98 1 3.5 4 14 15.14 0.30 3
D 1138 11.38 1 6 2 12 14.03 0.28 3
M 2310 23.1 1 6 4 24 24.57 0.49 4
``
Forebay Calculations
Landing at Lemay
Fort Collins, CO
A. Snow
3/4/2024
SCOURSTOP CALCULATIONS
Storm
Line
Diameter
(in.)
Flow Velocity
(cfs)
Mat Length
(ft)
Mat Width
(ft)
Quantity of
Mats
3/9 36 8.18 12 8 6
5 24 7.92 8 8 4
4/6 30 6.0 12 8 6
Note: Mat orientations at outlets have been modified to account for concrete pans
SCOURSTOP PROTECTION CALCULATIONS
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Purchase a license to generate PDF files without this notice.
ScourStop®
DESIGN GUIDE
Circular Culvert Outlet Protection
scourstop.com
PERFORMANCE AESTHETICS
NPDES-COMPLIANT COST-EFFECTIVE
the green solution to riprap
®
ScourStop transition mats protect against erosion and scour at culvert
outlets with a vegetated solution in areas traditionally protected with
rock or other hard armor.
ScourStop is part of a system that includes semi-rigid transition mats
installed over sod or turf reinforcement mats. Each 4’ x 4’ x 1/2” mat is
made of high-density polyethylene and secured tightly to the ground
with anchors.
why use the
SCOURSTOP SYSTEM?
- If velocity is greater than 16 fps, contact manufacturer for design assistance.
- ScourStop mats have been shown to at least double the effectiveness of turf
reinforcement mats.
- ScourStop fully vegetated channel (2:1 slope): velocity = 31 fps,
shear stress = 16 psf.
PIPE
DIAMETER
VELOCITY < 10 FT/SEC 10 < VELOCITY < 16 FT/SEC
TRANSITION
MAT W x L
QUANTITY
OF MATS
TRANSITION
MAT W x L
QUANTITY
OF MATS
12”4’ x 4’1 4’ x 8’2
24”8’ x 8’4 8’ x 12’6
36”8’ x 12’6 12’ x 20’15
48”12’ x 16’12 12’ x 24’18
60”12’ x 20’15 16’ x 32’32
72”16’ x 24’24 20’ x 36’45
Circular Culvert Outlet Protection
These are minimum recommendations. More ScourStop protection may be needed depending
upon site and soil conditions, per project engineer.
1. ScourStop mats must be installed over a soil cover: sod, seeded turf reinforcement mat (TRM), geotextile, or a combination thereof.
2. For steep slopes (>10%) or higher velocities (>10 ft/sec), sod is the recommended soil cover.
3. Follow manufacturer’s ScourStop Installation Guidelines to ensure proper installation.
4. Install ScourStop mats at maximum 1-2” below flowline of culvert or culvert apron. (No waterfall impacts onto ScourStop mats.)
5. Performance of protected area assumes stable downstream conditions.
Transition mat apron protects
culvert outlet.
*Width of protection:
Bottom width of channel and up
both side slopes to a depth at
least half the culvert diameter.
Protect bare/disturbed downstream
soils from erosion with appropriate
soil cover.
Use normal-depth calculator to
compute for downstream protection.
Install anchors per ScourStop Installation Guidelines.
Minimum depth 24” in compacted, cohesive soil.
Minimum depth 30” in loose, sandy, or wet soil.
Extra anchors as needed to secure mat tightly over soil cover.
Abut transition mats to end of culvert or culvert apron.
Adjacent mats abut together laterally and longitudinally.
Minimum 8 anchors per mat.
Extra anchors as needed for loose or wet soils.
Extra anchors as needed for uneven soil surface.
ScourStop®
Installation Recommendations
A
A
MAX. 1"-2" DROP
FROM CULVERT FLOWLINE
ONTO SCOURSTOP MATSCULVERT FLOWLINE
PROFILE VIEW
A LEADER in the GEOSYNTHETIC and EROSION CONTROL industries
Learn more about our products at: HanesGeo.com | 888.239.4539
the green solution to riprap
©2014 Leggett & Platt, Incorporated | 16959_1114
AA
C
APPENDIX C – LID AND WATER QUALITY
Sheet 1 of 2
Designer:
Company:
Date:
Project:
Location:
1. Basin Storage Volume
A) Effective Imperviousness of Tributary Area, Ia Ia =18.4 %
(100% if all paved and roofed areas upstream of rain garden)
B) Tributary Area's Imperviousness Ratio (i = Ia/100)i = 0.184
C) Water Quality Capture Volume (WQCV) for a 12-hour Drain Time WQCV = 0.09 watershed inches
(WQCV= 0.8 * (0.91* i3 - 1.19 * i2 + 0.78 * i)
D) Contributing Watershed Area (including rain garden area) Area = 153,821 sq ft
E) Water Quality Capture Volume (WQCV) Design Volume VWQCV =1,115 cu ft
Vol = (WQCV / 12) * Area
F) For Watersheds Outside of the Denver Region, Depth of d6 = in
Average Runoff Producing Storm
G) For Watersheds Outside of the Denver Region, VWQCV OTHER =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 (12-inch maximum)DWQCV =12 in
B) Rain Garden Side Slopes (Z = 4 min., horiz. dist per unit vertical) Z = 4.00 ft / ft
(Use "0" if rain garden has vertical walls)
C) Mimimum Flat Surface Area AMin =565 sq ft
D) Actual Flat Surface Area AActual =652 sq ft
E) Area at Design Depth (Top Surface Area)ATop =2650 sq ft
F) Rain Garden Total Volume VT=1,651 cu ft
(VT= ((ATop + AActual) / 2) * Depth)
3. Growing Media
4. Underdrain System
A) Are underdrains provided?1
B) Underdrain system orifice diameter for 12 hour drain time
i) Distance From Lowest Elevation of the Storage y =ft
Volume to the Center of the Orifice
ii) Volume to Drain in 12 Hours Vol12 =cu ft
iii) Orifice Diameter, 3/8" Minimum DO = in
Design Procedure Form: Rain Garden (RG)
A.S.
April 8, 2024
Landing at Lemay
Fort Collins
UD-BMP (Version 3.07, March 2018)
Choose One
Choose One
18" Rain Garden Growing Media
Other (Explain):
YES
NO
UD-BMP_v3.07, RG 4/8/2024, 4:04 PM
UD-BMP CALCULATION FOR
WQCV REQUIRED IN POND 2,
INCLUDING ALL AREAS ON
SITE NOT TREATED BY LID
Project Number:Project:
Project Location:
Calculations By:Date:
Sq. Ft. Acres
A 97,267 2.23 61%Rain Garden A 1,600 2,039 59,333
B 66,289 1.52 78%Rain Garden B 1,398 1,507 51,705
C 151,371 3.48 53%Chambers C 2,169 2,226 80,227
D 69,230 1.59 63%Rain Garden D 1,138 1,401 43,615
E 166,253 3.82 62%Chambers E 2,696 2,771 103,077
J 13,363 0.31 82%n/a 0 0 n/a
K 19,755 0.45 77%n/a 0 0 n/a
L 27,767 0.64 57%n/a 0 0 n/a
M 107,554 2.47 79%Rain Garden M 2,310 2,377 84,968
N 43,656 1.00 16%n/a 0 0 n/a
Total 762,505 15.27 62%11,311 12,321 422,924
Sq. Ft.Acres
Rain Garden A 97,267 2.23 61%A Rain Garden 1,600 59,333
Rain Garden B 66,289 1.52 78%B Rain Garden 1,398 51,705
Chambers C 151,371 3.48 53%C Chambers 2,169 80,227
Rain Garden D 69,230 1.59 63%D Rain Garden 1,183 43,615
Chambers E 166,253 3.82 62%E Chambers 2,696 103,077
Rain Garden M 107,554 2.47 79%M Rain Garden 2,310 84,968
Total 657,964 15.10 422,924
762,505 ft2
472,753 ft2
354,565 ft3
422,924 ft2
89.5%
LID Summary
AreaBasin ID Percent
Impervious LID ID
Landing at Lemay
2/26/2024
1791-003
Fort Collins, Colorado
ARS
Total Impervious
Area Treated (ft2)
Required
Volume (ft3)
LID Summary per Basin
Provided
Volume (ft3)
Impervious Area
(ft2)
LID Summary per LID Structure
LID Site Summary - New Impervious Area
Subbasin ID Treatment TypeLID ID
Volume per
UD-BMP (ft3)
Total Area of Current Development
Total Impervious Area
Total Impervious Area without LID Treatment:
Sub-basins J, K, L, N
Area
Weighted
%
Impervious
0 ft2
Total Treated Area
Percent Impervious Treated by LID
75% Required Minimum Area to be Treated
GAS
NO
R
T
H
L
E
M
A
Y
A
V
E
N
U
E
DUFF DRIVE
CO
R
D
O
V
A
R
O
A
D
LINK LANE
DETENTION
POND 2
RAIN
GARDEN A
RAIN
GARDEN D
DETENTION
POND 1
RAIN
GARDEN B
RAIN
GARDEN M
CO
R
D
O
V
A
R
O
A
D
KEYMAP
NOT TO SCALE
OF
SCALE:
PROJECT NO.
PR
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:
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:
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D
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:
SHEET:
HORIZ:
VERT:
CAUTION
The engineer preparing these
plans will not be responsible
for, or liable for, unauthorized
changes to or uses of these
plans. All changes must be
approved by the Professional
Engineer of these plans.
04
/
1
0
/
2
4
TH
E
L
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D
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1791-003
D.
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W
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T
NORTH
( IN FEET )
1 inch = ft.
Feet05050
50
100 150
LI
D
E
X
H
I
B
I
T
LID
1" = 50'
N/A
LID SUMMARY TABLE
TOTAL NEW (IMPROVED)
IMPERVIOUS AREA, (SF)458,951
TARGET TREATMENT AREA
(75%) (SF)344,213
TOTAL AREA TREATED BY
LID (SF) (GREEN HATCH)422,924
PERCENTAGE OF TOTAL 92.15%
TOTAL AREA NOT TREATED
BY LID (SF) (RED HATCH)36,027
PERCENTAGE OF TOTAL 7.85%
Sheet 1 of 2
Designer:
Company:
Date:
Project:
Location:
1. Basin Storage Volume
A) Effective Imperviousness of Tributary Area, Ia Ia =61.0 %
(100% if all paved and roofed areas upstream of rain garden)
B) Tributary Area's Imperviousness Ratio (i = Ia/100)i = 0.610
C) Water Quality Capture Volume (WQCV) for a 12-hour Drain Time WQCV = 0.19 watershed inches
(WQCV= 0.8 * (0.91* i3 - 1.19 * i2 + 0.78 * i)
D) Contributing Watershed Area (including rain garden area) Area = 97,267 sq ft
E) Water Quality Capture Volume (WQCV) Design Volume VWQCV =1,553 cu ft
Vol = (WQCV / 12) * Area
F) For Watersheds Outside of the Denver Region, Depth of d6 = in
Average Runoff Producing Storm
G) For Watersheds Outside of the Denver Region, VWQCV OTHER =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 (12-inch maximum)DWQCV =12 in
B) Rain Garden Side Slopes (Z = 4 min., horiz. dist per unit vertical) Z = 4.00 ft / ft
(Use "0" if rain garden has vertical walls)
C) Mimimum Flat Surface Area AMin =1187 sq ft
D) Actual Flat Surface Area AActual =1376 sq ft
E) Area at Design Depth (Top Surface Area)ATop =2702 sq ft
F) Rain Garden Total Volume VT=2,039 cu ft
(VT= ((ATop + AActual) / 2) * Depth)
3. Growing Media
4. Underdrain System
A) Are underdrains provided?1
B) Underdrain system orifice diameter for 12 hour drain time
i) Distance From Lowest Elevation of the Storage y =50.0 ft
Volume to the Center of the Orifice
ii) Volume to Drain in 12 Hours Vol12 =1,553 cu ft
iii) Orifice Diameter, 3/8" Minimum DO =1/2 in
Design Procedure Form: Rain Garden (RG)
AS
Avant Civil Group
March 1, 2024
Landing at Lemay
Rain Garden A
UD-BMP (Version 3.07, March 2018)
Choose One
Choose One
18" Rain Garden Growing Media
Other (Explain):
YES
NO
UD-BMP_v3.07_Rain Garden A, RG 3/1/2024, 10:21 AM
Sheet 1 of 2
Designer:
Company:
Date:
Project:
Location:
1. Basin Storage Volume
A) Effective Imperviousness of Tributary Area, Ia Ia =78.0 %
(100% if all paved and roofed areas upstream of rain garden)
B) Tributary Area's Imperviousness Ratio (i = Ia/100)i = 0.780
C) Water Quality Capture Volume (WQCV) for a 12-hour Drain Time WQCV = 0.25 watershed inches
(WQCV= 0.8 * (0.91* i3 - 1.19 * i2 + 0.78 * i)
D) Contributing Watershed Area (including rain garden area) Area = 66,289 sq ft
E) Water Quality Capture Volume (WQCV) Design Volume VWQCV =1,398 cu ft
Vol = (WQCV / 12) * Area
F) For Watersheds Outside of the Denver Region, Depth of d6 = in
Average Runoff Producing Storm
G) For Watersheds Outside of the Denver Region, VWQCV OTHER =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 (12-inch maximum)DWQCV =12 in
B) Rain Garden Side Slopes (Z = 4 min., horiz. dist per unit vertical) Z = 4.00 ft / ft
(Use "0" if rain garden has vertical walls)
C) Mimimum Flat Surface Area AMin =1034 sq ft
D) Actual Flat Surface Area AActual =1038 sq ft
E) Area at Design Depth (Top Surface Area)ATop =2179 sq ft
F) Rain Garden Total Volume VT=1,609 cu ft
(VT= ((ATop + AActual) / 2) * Depth)
3. Growing Media
4. Underdrain System
A) Are underdrains provided?1
B) Underdrain system orifice diameter for 12 hour drain time
i) Distance From Lowest Elevation of the Storage y =50.0 ft
Volume to the Center of the Orifice
ii) Volume to Drain in 12 Hours Vol12 =1,398 cu ft
iii) Orifice Diameter, 3/8" Minimum DO =7/16 in
Design Procedure Form: Rain Garden (RG)
AS
Avant Civil Group
March 1, 2024
Landing at Lemay
Rain Garden B
UD-BMP (Version 3.07, March 2018)
Choose One
Choose One
18" Rain Garden Growing Media
Other (Explain):
YES
NO
UD-BMP_v3.07_Rain Garden B, RG 3/1/2024, 10:31 AM
Sheet 1 of 2
Designer:
Company:
Date:
Project:
Location:
1. Basin Storage Volume
A) Effective Imperviousness of Tributary Area, Ia Ia =63.0 %
(100% if all paved and roofed areas upstream of rain garden)
B) Tributary Area's Imperviousness Ratio (i = Ia/100)i = 0.630
C) Water Quality Capture Volume (WQCV) for a 12-hour Drain Time WQCV = 0.20 watershed inches
(WQCV= 0.8 * (0.91* i3 - 1.19 * i2 + 0.78 * i)
D) Contributing Watershed Area (including rain garden area) Area = 69,230 sq ft
E) Water Quality Capture Volume (WQCV) Design Volume VWQCV =1,138 cu ft
Vol = (WQCV / 12) * Area
F) For Watersheds Outside of the Denver Region, Depth of d6 = in
Average Runoff Producing Storm
G) For Watersheds Outside of the Denver Region, VWQCV OTHER =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 (12-inch maximum)DWQCV =12 in
B) Rain Garden Side Slopes (Z = 4 min., horiz. dist per unit vertical) Z = 4.00 ft / ft
(Use "0" if rain garden has vertical walls)
C) Mimimum Flat Surface Area AMin =872 sq ft
D) Actual Flat Surface Area AActual =983 sq ft
E) Area at Design Depth (Top Surface Area)ATop =1818 sq ft
F) Rain Garden Total Volume VT=1,401 cu ft
(VT= ((ATop + AActual) / 2) * Depth)
3. Growing Media
4. Underdrain System
A) Are underdrains provided?1
B) Underdrain system orifice diameter for 12 hour drain time
i) Distance From Lowest Elevation of the Storage y =50.0 ft
Volume to the Center of the Orifice
ii) Volume to Drain in 12 Hours Vol12 =1,138 cu ft
iii) Orifice Diameter, 3/8" Minimum DO =3/8 in
Design Procedure Form: Rain Garden (RG)
AS
Avant Civil Group
March 1, 2024
Landing at Lemay
Rain Garden D
UD-BMP (Version 3.07, March 2018)
Choose One
Choose One
18" Rain Garden Growing Media
Other (Explain):
YES
NO
UD-BMP_v3.07_Rain Garden D, RG 3/1/2024, 10:32 AM
Sheet 1 of 2
Designer:
Company:
Date:
Project:
Location:
1. Basin Storage Volume
A) Effective Imperviousness of Tributary Area, Ia Ia =79.0 %
(100% if all paved and roofed areas upstream of rain garden)
B) Tributary Area's Imperviousness Ratio (i = Ia/100)i = 0.790
C) Water Quality Capture Volume (WQCV) for a 12-hour Drain Time WQCV = 0.26 watershed inches
(WQCV= 0.8 * (0.91* i3 - 1.19 * i2 + 0.78 * i)
D) Contributing Watershed Area (including rain garden area) Area = 107,554 sq ft
E) Water Quality Capture Volume (WQCV) Design Volume VWQCV =2,310 cu ft
Vol = (WQCV / 12) * Area
F) For Watersheds Outside of the Denver Region, Depth of d6 = in
Average Runoff Producing Storm
G) For Watersheds Outside of the Denver Region, VWQCV OTHER =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 (12-inch maximum)DWQCV =12 in
B) Rain Garden Side Slopes (Z = 4 min., horiz. dist per unit vertical) Z = 0.00 ft / ft
(Use "0" if rain garden has vertical walls)
C) Mimimum Flat Surface Area AMin =1699 sq ft
D) Actual Flat Surface Area AActual =2377 sq ft
E) Area at Design Depth (Top Surface Area)ATop =2377 sq ft
F) Rain Garden Total Volume VT=2,377 cu ft
(VT= ((ATop + AActual) / 2) * Depth)
3. Growing Media
4. Underdrain System
A) Are underdrains provided?1
B) Underdrain system orifice diameter for 12 hour drain time
i) Distance From Lowest Elevation of the Storage y =50.0 ft
Volume to the Center of the Orifice
ii) Volume to Drain in 12 Hours Vol12 =2,310 cu ft
iii) Orifice Diameter, 3/8" Minimum DO =9/16 in
Design Procedure Form: Rain Garden (RG)
AS
Avant Civil Group
March 1, 2024
Landing at Lemay
Rain Garden M
UD-BMP (Version 3.07, March 2018)
Choose One
Choose One
18" Rain Garden Growing Media
Other (Explain):
YES
NO
UD-BMP_v3.07_Rain Garden M, RG 3/1/2024, 10:33 AM
Project Title Date:
Project Number Calcs By:
City
Basins
0.8
WQCV = Watershed inches of Runoff (inches)53%
a = Runoff Volume Reduction (constant)
i = Total imperviousness Ratio (i = Iwq/100)0.172 in
A =3.48 ac
V = 0.0498 ac-ft
V = Water Quality Design Volume (ac-ft)
WQCV = Water Quality Capture Volume (inches)
A = Watershed Area (acres)
2169 cu. ft.
Drain Time
a =
i =
WQCV =
Figure EDB-2 - Water Quality Capture Volume (WQCV), 80th Percentile Runoff Event
The Landing at Lemay March 1, 2024
1791-003 ARS
Fort Collins
Stormtech Chambers C
0.231
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0.45
0.5
0 0.
1
0.
2
0.
3
0.
4
0.
5
0.
6
0.
7
0.
8
0.
9
1
WQ
C
V
(
w
a
t
e
r
s
h
e
d
i
n
c
h
e
s
)
Total Imperviousness Ratio (i = Iwq/100)
Water Quality Capture Volume
6 hr
12 hr
24 hr
40 hr
()iii78.019.10.91aWQCV 23 +-=
()iii78.019.10.91aWQCV 23 +-=
AV*
12
WQCV
=
12 hr
User Inputs
Chamber Model: SC-740
Outlet Control Structure: Yes
Project Name: Landing at Lemay -
South
Engineer: Austin Snow
Project Location: Colorado
Measurement Type: Imperial
Required Storage Volume: 2169 cubic ft.
Stone Porosity: 40%
Stone Foundation Depth: 6 in.
Stone Above Chambers: 6 in.
Average Cover Over Chambers: 18 in.
Design Constraint Dimensions:(17 ft. x 70 ft.)
Results
System Volume and Bed Size
Installed Storage Volume: 2226.37 cubic ft.
Storage Volume Per Chamber: 45.90 cubic ft.
Number Of Chambers Required: 25
Number Of End Caps Required: 6
Chamber Rows: 3
Maximum Length:71.58 ft.
Maximum Width: 16.35 ft.
Approx. Bed Size Required: 1098.48 square ft.
System Components
Amount Of Stone Required: 100 cubic yards
Volume Of Excavation (Not Including
Fill):
143 cubic yards
Total Non-woven Geotextile Required:375 square yards
Woven Geotextile Required (excluding
Isolator Row):
1 square yards
Woven Geotextile Required (Isolator
Row):
44 square yards
Total Woven Geotextile Required:44 square yards
Impervious Liner Required:0 square yards
Project Title Date:
Project Number Calcs By:
City
Basins
0.8
WQCV = Watershed inches of Runoff (inches)62%
a = Runoff Volume Reduction (constant)
i = Total imperviousness Ratio (i = Iwq/100)0.194 in
A =3.82 ac
V = 0.0619 ac-ft
V = Water Quality Design Volume (ac-ft)
WQCV = Water Quality Capture Volume (inches)
A = Watershed Area (acres)
2696 cu. ft.
Drain Time
a =
i =
WQCV =
Figure EDB-2 - Water Quality Capture Volume (WQCV), 80th Percentile Runoff Event
The Landing at Lemay March 1, 2024
1791-003 ARS
Fort Collins
Stormtech Chambers E
0.231
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0.45
0.5
0 0.
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0.
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Total Imperviousness Ratio (i = Iwq/100)
Water Quality Capture Volume
6 hr
12 hr
24 hr
40 hr
()iii78.019.10.91aWQCV 23 +-=
()iii78.019.10.91aWQCV 23 +-=
AV*
12
WQCV
=
12 hr
User Inputs
Chamber Model: SC-740
Outlet Control Structure: Yes
Project Name: Landing @ Lemay
Engineer: Austin Snow
Project Location: Colorado
Measurement Type: Imperial
Required Storage Volume: 2696 cubic ft.
Stone Porosity: 40%
Stone Foundation Depth: 6 in.
Stone Above Chambers: 6 in.
Average Cover Over Chambers: 18 in.
Design Constraint Dimensions:(30 ft. x 75 ft.)
Results
System Volume and Bed Size
Installed Storage Volume: 2785.56 cubic ft.
Storage Volume Per Chamber: 45.90 cubic ft.
Number Of Chambers Required: 32
Number Of End Caps Required: 8
Chamber Rows: 4
Maximum Length:64.46 ft.
Maximum Width: 21.10 ft.
Approx. Bed Size Required: 1360.20 square ft.
System Components
Amount Of Stone Required: 122 cubic yards
Volume Of Excavation (Not Including
Fill):
177 cubic yards
Total Non-woven Geotextile Required:443 square yards
Woven Geotextile Required (excluding
Isolator Row):
1 square yards
Woven Geotextile Required (Isolator
Row):
40 square yards
Total Woven Geotextile Required:40 square yards
Impervious Liner Required:0 square yards
©2023 ADS, INC.
PROJECT INFORMATION
ADS SALES REP:
ENGINEERED
PRODUCT
MANAGER:
PROJECT NO:
THE LANDING AT LEMAY
FORT COLLINS - CO
MARK KAELBERER
720-256-8225
MARK.KAELBERER@ADSPIPE.COM
S377242
Advanced Drainage Systems, Inc.
JEROME MAGSINO
303-349-7555
JEROME.MAGSINO@ADSPIPE.COM
IMPORTANT - NOTES FOR THE BIDDING AND INSTALLATION OF THE SC-740 SYSTEM
1.STORMTECH SC-740 CHAMBERS SHALL NOT BE INSTALLED UNTIL THE MANUFACTURER'S REPRESENTATIVE HAS COMPLETED A
PRE-CONSTRUCTION MEETING WITH THE INSTALLERS.
2.STORMTECH SC-740 CHAMBERS SHALL BE INSTALLED IN ACCORDANCE WITH THE "STORMTECH SC-310/SC-740/SC-800/DC-780 CONSTRUCTION
GUIDE".
3.CHAMBERS ARE NOT TO BE BACKFILLED WITH A DOZER OR AN EXCAVATOR SITUATED OVER THE CHAMBERS.
STORMTECH RECOMMENDS 3 BACKFILL METHODS:
·STONESHOOTER LOCATED OFF THE CHAMBER BED.
·BACKFILL AS ROWS ARE BUILT USING AN EXCAVATOR ON THE FOUNDATION STONE OR SUBGRADE.
·BACKFILL FROM OUTSIDE THE EXCAVATION USING A LONG BOOM HOE OR EXCAVATOR.
4.THE FOUNDATION STONE SHALL BE LEVELED AND COMPACTED PRIOR TO PLACING CHAMBERS.
5.JOINTS BETWEEN CHAMBERS SHALL BE PROPERLY SEATED PRIOR TO PLACING STONE.
6.MAINTAIN MINIMUM - 6" (150 mm) SPACING BETWEEN THE CHAMBER ROWS.
7.EMBEDMENT STONE SURROUNDING CHAMBERS MUST BE A CLEAN, CRUSHED, ANGULAR STONE 3/4-2" (20-50 mm).
8.THE CONTRACTOR MUST REPORT ANY DISCREPANCIES WITH CHAMBER FOUNDATION MATERIALS BEARING CAPACITIES TO THE SITE DESIGN
ENGINEER.
9.ADS RECOMMENDS THE USE OF "FLEXSTORM CATCH IT" INSERTS DURING CONSTRUCTION FOR ALL INLETS TO PROTECT THE SUBSURFACE
STORMWATER MANAGEMENT SYSTEM FROM CONSTRUCTION SITE RUNOFF.
NOTES FOR CONSTRUCTION EQUIPMENT
1.STORMTECH SC-740 CHAMBERS SHALL BE INSTALLED IN ACCORDANCE WITH THE "STORMTECH SC-310/SC-740/SC-800/DC-780 CONSTRUCTION
GUIDE".
2.THE USE OF CONSTRUCTION EQUIPMENT OVER SC-740 CHAMBERS IS LIMITED:
·NO EQUIPMENT IS ALLOWED ON BARE CHAMBERS.
·NO RUBBER TIRED LOADERS, DUMP TRUCKS, OR EXCAVATORS ARE ALLOWED UNTIL PROPER FILL DEPTHS ARE REACHED IN ACCORDANCE
WITH THE "STORMTECH SC-310/SC-740/SC-800/DC-780 CONSTRUCTION GUIDE".
·WEIGHT LIMITS FOR CONSTRUCTION EQUIPMENT CAN BE FOUND IN THE "STORMTECH SC-310/SC-740/SC-800/DC-780 CONSTRUCTION GUIDE".
3.FULL 36" (900 mm) OF STABILIZED COVER MATERIALS OVER THE CHAMBERS IS REQUIRED FOR DUMP TRUCK TRAVEL OR DUMPING.
USE OF A DOZER TO PUSH EMBEDMENT STONE BETWEEN THE ROWS OF CHAMBERS MAY CAUSE DAMAGE TO THE CHAMBERS AND IS NOT AN
ACCEPTABLE BACKFILL METHOD. ANY CHAMBERS DAMAGED BY THE "DUMP AND PUSH" METHOD ARE NOT COVERED UNDER THE STORMTECH
STANDARD WARRANTY.
CONTACT STORMTECH AT 1-888-892-2694 WITH ANY QUESTIONS ON INSTALLATION REQUIREMENTS OR WEIGHT LIMITS FOR CONSTRUCTION EQUIPMENT.
SC-740 STORMTECH CHAMBER SPECIFICATIONS
1.CHAMBERS SHALL BE STORMTECH SC-740.
2.CHAMBERS SHALL BE ARCH-SHAPED AND SHALL BE MANUFACTURED FROM VIRGIN, IMPACT-MODIFIED POLYPROPYLENE
COPOLYMERS.
3.CHAMBERS SHALL MEET THE REQUIREMENTS OF ASTM F2418, "STANDARD SPECIFICATION FOR POLYPROPYLENE (PP) CORRUGATED
WALL STORMWATER COLLECTION CHAMBERS".
4.CHAMBER ROWS SHALL PROVIDE CONTINUOUS, UNOBSTRUCTED INTERNAL SPACE WITH NO INTERNAL SUPPORTS THAT WOULD
IMPEDE FLOW OR LIMIT ACCESS FOR INSPECTION.
5.THE STRUCTURAL DESIGN OF THE CHAMBERS, THE STRUCTURAL BACKFILL, AND THE INSTALLATION REQUIREMENTS SHALL ENSURE
THAT THE LOAD FACTORS SPECIFIED IN THE AASHTO LRFD BRIDGE DESIGN SPECIFICATIONS, SECTION 12.12, ARE MET FOR: 1)
LONG-DURATION DEAD LOADS AND 2) SHORT-DURATION LIVE LOADS, BASED ON THE AASHTO DESIGN TRUCK WITH CONSIDERATION
FOR IMPACT AND MULTIPLE VEHICLE PRESENCES.
6.CHAMBERS SHALL BE DESIGNED, TESTED AND ALLOWABLE LOAD CONFIGURATIONS DETERMINED IN ACCORDANCE WITH ASTM F2787,
"STANDARD PRACTICE FOR STRUCTURAL DESIGN OF THERMOPLASTIC CORRUGATED WALL STORMWATER COLLECTION CHAMBERS".
LOAD CONFIGURATIONS SHALL INCLUDE: 1) INSTANTANEOUS (<1 MIN) AASHTO DESIGN TRUCK LIVE LOAD ON MINIMUM COVER 2)
MAXIMUM PERMANENT (75-YR) COVER LOAD AND 3) ALLOWABLE COVER WITH PARKED (1-WEEK) AASHTO DESIGN TRUCK.
7.REQUIREMENTS FOR HANDLING AND INSTALLATION:
·TO MAINTAIN THE WIDTH OF CHAMBERS DURING SHIPPING AND HANDLING, CHAMBERS SHALL HAVE INTEGRAL, INTERLOCKING
STACKING LUGS.
·TO ENSURE A SECURE JOINT DURING INSTALLATION AND BACKFILL, THE HEIGHT OF THE CHAMBER JOINT SHALL NOT BE LESS
THAN 2”.
·TO ENSURE THE INTEGRITY OF THE ARCH SHAPE DURING INSTALLATION, a) THE ARCH STIFFNESS CONSTANT SHALL BE
GREATER THAN OR EQUAL TO 550 LBS/FT/%. THE ASC IS DEFINED IN SECTION 6.2.8 OF ASTM F2418. AND b) TO RESIST
CHAMBER DEFORMATION DURING INSTALLATION AT ELEVATED TEMPERATURES (ABOVE 73° F / 23° C), CHAMBERS SHALL BE
PRODUCED FROM REFLECTIVE GOLD OR YELLOW COLORS.
8.ONLY CHAMBERS THAT ARE APPROVED BY THE SITE DESIGN ENGINEER WILL BE ALLOWED. UPON REQUEST BY THE SITE DESIGN
ENGINEER OR OWNER, THE CHAMBER MANUFACTURER SHALL SUBMIT A STRUCTURAL EVALUATION FOR APPROVAL BEFORE
DELIVERING CHAMBERS TO THE PROJECT SITE AS FOLLOWS:
·THE STRUCTURAL EVALUATION SHALL BE SEALED BY A REGISTERED PROFESSIONAL ENGINEER.
·THE STRUCTURAL EVALUATION SHALL DEMONSTRATE THAT THE SAFETY FACTORS ARE GREATER THAN OR EQUAL TO 1.95 FOR
DEAD LOAD AND 1.75 FOR LIVE LOAD, THE MINIMUM REQUIRED BY ASTM F2787 AND BY SECTIONS 3 AND 12.12 OF THE AASHTO
LRFD BRIDGE DESIGN SPECIFICATIONS FOR THERMOPLASTIC PIPE.
·THE TEST DERIVED CREEP MODULUS AS SPECIFIED IN ASTM F2418 SHALL BE USED FOR PERMANENT DEAD LOAD DESIGN
EXCEPT THAT IT SHALL BE THE 75-YEAR MODULUS USED FOR DESIGN.
9.CHAMBERS AND END CAPS SHALL BE PRODUCED AT AN ISO 9001 CERTIFIED MANUFACTURING FACILITY.
FOR STORMTECH
INSTALLATION INSTRUCTIONS
VISIT OUR WEBSITE
SiteAssist
CONCEPTUAL LAYOUT FOR PROPOSED CONVERSION OR SYSTEM BUDGETING AND
COMPARISON ONLY. NOT INTENDED FOR ESTIMATING, BIDDING, OR CONSTRUCTION
UNLESS APPROVED BUY ENGINEER OF RECORD.
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PROPOSED LAYOUT - NORTH SYSTEM
32 STORMTECH SC-740 CHAMBERS
8 STORMTECH SC-740 END CAPS
6 STONE ABOVE (in)
6 STONE BELOW (in)
40 % STONE VOID
1387 SYSTEM AREA (ft²)
173 SYSTEM PERIMETER (ft)
PROPOSED ELEVATIONS - NORTH SYSTEM
4949.36 MAXIMUM ALLOWABLE GRADE (TOP OF PAVEMENT/UNPAVED)
4943.36 MINIMUM ALLOWABLE GRADE (UNPAVED WITH TRAFFIC)
4942.86 MINIMUM ALLOWABLE GRADE (UNPAVED NO TRAFFIC)
4942.86 MINIMUM ALLOWABLE GRADE (BASE OF FLEXIBLE PAVEMENT)
4942.86 MINIMUM ALLOWABLE GRADE (TOP OF RIGID PAVEMENT)
4941.86 TOP OF STONE
4941.36 TOP OF SC-740 CHAMBER
4938.87 24" BOTTOM MANIFOLD INVERT
4938.87 24" ISOLATOR ROW PLUS CONNECTION INVERT
4938.86 BOTTOM OF SC-740 CHAMBER
4938.36 UNDERDRAIN INVERT
4938.36 BOTTOM OF STONE
NOTES
·MANIFOLD SIZE TO BE DETERMINED BY SITE DESIGN ENGINEER. SEE TECHNICAL NOTE 6.32 FOR MANIFOLD SIZING GUIDANCE.
·DUE TO THE ADAPTATION OF THIS CHAMBER SYSTEM TO SPECIFIC SITE AND DESIGN CONSTRAINTS, IT MAY BE NECESSARY TO CUT AND COUPLE ADDITIONAL PIPE TO STANDARD MANIFOLD
COMPONENTS IN THE FIELD.
·THIS CHAMBER SYSTEM WAS DESIGNED WITHOUT SITE-SPECIFIC INFORMATION ON SOIL CONDITIONS OR BEARING CAPACITY. THE SITE DESIGN ENGINEER IS RESPONSIBLE FOR DETERMINING THE
SUITABILITY OF THE SOIL AND PROVIDING THE BEARING CAPACITY OF THE INSITU SOILS. THE BASE STONE DEPTH MAY BE INCREASED OR DECREASED ONCE THIS INFORMATION IS PROVIDED.
·THE SITE DESIGN ENGINEER MUST REVIEW ELEVATIONS AND IF NECESSARY ADJUST GRADING TO ENSURE THE CHAMBER COVER REQUIREMENTS ARE MET.
·ATTENTION: THIS DRAWING IS NOT INTENDED FOR USE IN BIDDING OR CONSTRUCTION WITHOUT THE PRIOR APPROVAL OF THE PROJECT'S ENGINEER OF RECORD (EOR). AS WITH ALL
PROPOSED ADS LAYOUTS, THE EOR SHOULD REVIEW AND APPROVE THIS DRAWING PRIOR TO USE IN BIDDING AND/OR CONSTRUCTION. IT IS THE ULTIMATE RESPONSIBILITY OF THE EOR TO
ENSURE THAT THE PRODUCT(S) DEPICTED AND THE ASSOCIATED DETAILS MEET ALL APPLICABLE LAWS, REGULATIONS, AND PROJECT REQUIREMENTS.
ISOLATOR ROW PLUS (SEE DETAIL)
PLACE MINIMUM 12.5' OF ADSPLUS625 WOVEN GEOTEXTILE
OVER BEDDING STONE AND UNDERNEATH CHAMBER FEET
FOR SCOUR PROTECTION AT ALL CHAMBER INLET ROWS
BED LIMITS
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65.40'
58.54'
21
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18
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5
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'
INSPECTION PORT (TYP 4 PLACES)
INSTALL FLAMP ON 24" ACCESS PIPE
PART#SC74024RAMP
(TYP 2 PLACES)
6" ADS N-12 DUAL WALL PERFORATED HDPE UNDERDRAIN
(SIZE TBD BY ENGINEER / SOLID OUTSIDE PERIMETER STONE)
STRUCTURE PER PLAN
(DESIGN BY ENGINEER / PROVIDED BY OTHERS)
OUTLET STRUCTURE PER PLAN W/WEIR
(DESIGN BY ENGINEER / PROVIDED BY OTHERS)
24" X 24" ADS N-12 BOTTOM MANIFOLD
INVERT 0.1" ABOVE CHAMBER BASE
(SEE NOTES)
24" EZ END CAP, PART# SC740ECEZ
TYP OF ALL SC-740 24" CONNECTIONS &
24" ISOLATOR ROW PLUS CONNECTIONS
PROPOSED 30" NYLOPLAST BASIN
(24" SUMP MIN)
PROPOSED 30" NYLOPLAST BASIN
(24" SUMP MIN)
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CONCEPTUAL LAYOUT - SOUTH SYSTEM
25 STORMTECH SC-740 CHAMBERS
6 STORMTECH SC-740 END CAPS
6 STONE ABOVE (in)
6 STONE BELOW (in)
40 % STONE VOID
1122 SYSTEM AREA (ft²)
178 SYSTEM PERIMETER (ft)
CONCEPTUAL ELEVATIONS - SOUTH SYSTEM
11.00 MAXIMUM ALLOWABLE GRADE (TOP OF PAVEMENT/UNPAVED)
5.00 MINIMUM ALLOWABLE GRADE (UNPAVED WITH TRAFFIC)
4.50 MINIMUM ALLOWABLE GRADE (UNPAVED NO TRAFFIC)
4.50 MINIMUM ALLOWABLE GRADE (BASE OF FLEXIBLE PAVEMENT)
4.50 MINIMUM ALLOWABLE GRADE (TOP OF RIGID PAVEMENT)
3.50 TOP OF STONE
3.00 TOP OF SC-740 CHAMBER
0.50 BOTTOM OF SC-740 CHAMBER
0.00 BOTTOM OF STONE
ISOLATOR ROW PLUS (SEE DETAIL)
PLACE MINIMUM 12.5' OF ADSPLUS625 WOVEN GEOTEXTILE
OVER BEDDING STONE AND UNDERNEATH CHAMBER FEET
FOR SCOUR PROTECTION AT ALL CHAMBER INLET ROWS
BED LIMITS
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NOTES
·MANIFOLD SIZE TO BE DETERMINED BY SITE DESIGN ENGINEER. SEE TECHNICAL NOTE 6.32 FOR MANIFOLD SIZING GUIDANCE.
·DUE TO THE ADAPTATION OF THIS CHAMBER SYSTEM TO SPECIFIC SITE AND DESIGN CONSTRAINTS, IT MAY BE NECESSARY TO CUT AND COUPLE ADDITIONAL PIPE TO STANDARD MANIFOLD
COMPONENTS IN THE FIELD.
·THIS CHAMBER SYSTEM WAS DESIGNED WITHOUT SITE-SPECIFIC INFORMATION ON SOIL CONDITIONS OR BEARING CAPACITY. THE SITE DESIGN ENGINEER IS RESPONSIBLE FOR DETERMINING THE
SUITABILITY OF THE SOIL AND PROVIDING THE BEARING CAPACITY OF THE INSITU SOILS. THE BASE STONE DEPTH MAY BE INCREASED OR DECREASED ONCE THIS INFORMATION IS PROVIDED.
·THE SITE DESIGN ENGINEER MUST REVIEW ELEVATIONS AND IF NECESSARY ADJUST GRADING TO ENSURE THE CHAMBER COVER REQUIREMENTS ARE MET.
·THE STORMTECH SYSTEM DEPICTED DOES NOT CONTAIN PROPER WATER QUALITY MEASURES. ABSENCE OF WATER QUALITY MEASURES CAN RESULT IN UNTREATED STORMWATER. ADS
RECOMMENDS THE USE OF ISOLATOR ROW PLUS AND AN UPSTREAM HIGH FLOW BYPASS ON ALL STORMTECH SYSTEMS TO PROPERLY DIRECT THE FIRST FLUSH.
·ATTENTION: THIS DRAWING IS NOT INTENDED FOR USE IN BIDDING OR CONSTRUCTION WITHOUT THE PRIOR APPROVAL OF THE PROJECT'S ENGINEER OF RECORD (EOR). AS WITH ALL
PROPOSED ADS LAYOUTS, THE EOR SHOULD REVIEW AND APPROVE THIS DRAWING PRIOR TO USE IN BIDDING AND/OR CONSTRUCTION. IT IS THE ULTIMATE RESPONSIBILITY OF THE EOR TO
ENSURE THAT THE PRODUCT(S) DEPICTED AND THE ASSOCIATED DETAILS MEET ALL APPLICABLE LAWS, REGULATIONS, AND PROJECT REQUIREMENTS.
·NOT FOR CONSTRUCTION: THIS LAYOUT IS FOR DIMENSIONAL PURPOSES ONLY TO PROVE CONCEPT & THE REQUIRED STORAGE VOLUME CAN BE ACHIEVED ON SITE.
6" ADS N-12 DUAL WALL PERFORATED HDPE UNDERDRAIN
(SIZE TBD BY ENGINEER / SOLID OUTSIDE PERIMETER STONE)
30" NYLOPLAST BASIN PER PLAN
(24" SUMP MIN)
6.
9
5
'
9.
5
0
'
7.13'65.20'
16
.
5
4
'
13
.
7
5
'
58.54'
65.66'
30" NYLOPLAST BASIN PER PLAN
(24" SUMP MIN)
18" X18" BOTTOM MANIFOLD
INVERT 1.6" ABOVE CHAMBER BASE
(SEE NOTES)
18" PREFABRICATED END CAP, PART# SC740EPE18B
TYP OF ALL SC-740 18" BOTTOM CONNECTIONS
24" EZ END CAP, PART# SC740ECEZ
TYP OF ALL SC-740 24" CONNECTIONS &
24" ISOLATOR ROW PLUS CONNECTIONS
INSTALL FLAMP ON 24" ACCESS PIPE
PART#SC74024RAMP
(TYP 3 PLACES)
72.31'
INSPECTION PORT (TYP 3 PLACES)
INLET/OUTLET STRUCTURE PER PLAN
SHOWN AS 30" NYLOPLAST BASIN
(24" SUMP MIN)
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ACCEPTABLE FILL MATERIALS: STORMTECH SC-740 CHAMBER SYSTEMS
PLEASE NOTE:
1.THE LISTED AASHTO DESIGNATIONS ARE FOR GRADATIONS ONLY. THE STONE MUST ALSO BE CLEAN, CRUSHED, ANGULAR. FOR EXAMPLE, A SPECIFICATION FOR #4 STONE WOULD STATE: "CLEAN, CRUSHED, ANGULAR NO. 4 (AASHTO M43) STONE".
2.STORMTECH COMPACTION REQUIREMENTS ARE MET FOR 'A' LOCATION MATERIALS WHEN PLACED AND COMPACTED IN 6" (150 mm) (MAX) LIFTS USING TWO FULL COVERAGES WITH A VIBRATORY COMPACTOR.
3.WHERE INFILTRATION SURFACES MAY BE COMPROMISED BY COMPACTION, FOR STANDARD DESIGN LOAD CONDITIONS, A FLAT SURFACE MAY BE ACHIEVED BY RAKING OR DRAGGING WITHOUT COMPACTION EQUIPMENT. FOR SPECIAL LOAD DESIGNS, CONTACT STORMTECH FOR
COMPACTION REQUIREMENTS.
4.ONCE LAYER 'C' IS PLACED, ANY SOIL/MATERIAL CAN BE PLACED IN LAYER 'D' UP TO THE FINISHED GRADE. MOST PAVEMENT SUBBASE SOILS CAN BE USED TO REPLACE THE MATERIAL REQUIREMENTS OF LAYER 'C' OR 'D' AT THE SITE DESIGN ENGINEER'S DISCRETION.
5.WHERE RECYCLED CONCRETE AGGREGATE IS USED IN LAYERS 'A' OR 'B' THE MATERIAL SHOULD ALSO MEET THE ACCEPTABILITY CRITERIA OUTLINED IN TECHNICAL NOTE 6.20 "RECYCLED CONCRETE STRUCTURAL BACKFILL".
NOTES:
1.CHAMBERS SHALL MEET THE REQUIREMENTS OF ASTM F2418, "STANDARD SPECIFICATION FOR POLYPROPYLENE (PP) CORRUGATED WALL STORMWATER COLLECTION CHAMBERS".
2.SC-740 CHAMBERS SHALL BE DESIGNED IN ACCORDANCE WITH ASTM F2787 "STANDARD PRACTICE FOR STRUCTURAL DESIGN OF THERMOPLASTIC CORRUGATED WALL STORMWATER COLLECTION CHAMBERS".
3.THE SITE DESIGN ENGINEER IS RESPONSIBLE FOR ASSESSING THE BEARING RESISTANCE (ALLOWABLE BEARING CAPACITY) OF THE SUBGRADE SOILS AND THE DEPTH OF FOUNDATION STONE WITH
CONSIDERATION FOR THE RANGE OF EXPECTED SOIL MOISTURE CONDITIONS.
4.PERIMETER STONE MUST BE EXTENDED HORIZONTALLY TO THE EXCAVATION WALL FOR BOTH VERTICAL AND SLOPED EXCAVATION WALLS.
5.REQUIREMENTS FOR HANDLING AND INSTALLATION:
·TO MAINTAIN THE WIDTH OF CHAMBERS DURING SHIPPING AND HANDLING, CHAMBERS SHALL HAVE INTEGRAL, INTERLOCKING STACKING LUGS.
·TO ENSURE A SECURE JOINT DURING INSTALLATION AND BACKFILL, THE HEIGHT OF THE CHAMBER JOINT SHALL NOT BE LESS THAN 2”.
·TO ENSURE THE INTEGRITY OF THE ARCH SHAPE DURING INSTALLATION, a) THE ARCH STIFFNESS CONSTANT AS DEFINED IN SECTION 6.2.8 OF ASTM F2418 SHALL BE GREATER THAN OR EQUAL TO 550
LBS/FT/%. AND b) TO RESIST CHAMBER DEFORMATION DURING INSTALLATION AT ELEVATED TEMPERATURES (ABOVE 73° F / 23° C), CHAMBERS SHALL BE PRODUCED FROM REFLECTIVE GOLD OR YELLOW
COLORS.
MATERIAL LOCATION DESCRIPTION AASHTO MATERIAL
CLASSIFICATIONS COMPACTION / DENSITY REQUIREMENT
D
FINAL FILL: FILL MATERIAL FOR LAYER 'D' STARTS FROM THE
TOP OF THE 'C' LAYER TO THE BOTTOM OF FLEXIBLE
PAVEMENT OR UNPAVED FINISHED GRADE ABOVE. NOTE THAT
PAVEMENT SUBBASE MAY BE PART OF THE 'D' LAYER.
ANY SOIL/ROCK MATERIALS, NATIVE SOILS, OR PER ENGINEER'S PLANS.
CHECK PLANS FOR PAVEMENT SUBGRADE REQUIREMENTS.N/A
PREPARE PER SITE DESIGN ENGINEER'S PLANS. PAVED
INSTALLATIONS MAY HAVE STRINGENT MATERIAL AND
PREPARATION REQUIREMENTS.
C
INITIAL FILL: FILL MATERIAL FOR LAYER 'C' STARTS FROM THE
TOP OF THE EMBEDMENT STONE ('B' LAYER) TO 18" (450 mm)
ABOVE THE TOP OF THE CHAMBER. NOTE THAT PAVEMENT
SUBBASE MAY BE A PART OF THE 'C' LAYER.
GRANULAR WELL-GRADED SOIL/AGGREGATE MIXTURES, <35% FINES OR
PROCESSED AGGREGATE.
MOST PAVEMENT SUBBASE MATERIALS CAN BE USED IN LIEU OF THIS
LAYER.
AASHTO M145¹
A-1, A-2-4, A-3
OR
AASHTO M43¹
3, 357, 4, 467, 5, 56, 57, 6, 67, 68, 7, 78, 8, 89, 9, 10
BEGIN COMPACTIONS AFTER 12" (300 mm) OF MATERIAL OVER
THE CHAMBERS IS REACHED. COMPACT ADDITIONAL LAYERS IN
6" (150 mm) MAX LIFTS TO A MIN. 95% PROCTOR DENSITY FOR
WELL GRADED MATERIAL AND 95% RELATIVE DENSITY FOR
PROCESSED AGGREGATE MATERIALS. ROLLER GROSS
VEHICLE WEIGHT NOT TO EXCEED 12,000 lbs (53 kN). DYNAMIC
FORCE NOT TO EXCEED 20,000 lbs (89 kN).
B
EMBEDMENT STONE: FILL SURROUNDING THE CHAMBERS
FROM THE FOUNDATION STONE ('A' LAYER) TO THE 'C' LAYER
ABOVE.
CLEAN, CRUSHED, ANGULAR STONE OR RECYCLED CONCRETE5 AASHTO M43¹
3, 357, 4, 467, 5, 56, 57 NO COMPACTION REQUIRED.
A FOUNDATION STONE: FILL BELOW CHAMBERS FROM THE
SUBGRADE UP TO THE FOOT (BOTTOM) OF THE CHAMBER.CLEAN, CRUSHED, ANGULAR STONE OR RECYCLED CONCRETE5 AASHTO M43¹
3, 357, 4, 467, 5, 56, 57 PLATE COMPACT OR ROLL TO ACHIEVE A FLAT SURFACE.2,3
18"
(450 mm) MIN*
8'
(2.4 m)
MAX
6" (150 mm) MIN
D
C
B
A
12" (300 mm) MIN
ADS GEOSYNTHETICS 601T NON-WOVEN GEOTEXTILE ALL
AROUND CLEAN, CRUSHED, ANGULAR STONE IN A & B LAYERS
12" (300 mm) MIN51" (1295 mm)6"
(150 mm) MIN
30"
(762 mm)
DEPTH OF STONE TO BE DETERMINED
BY SITE DESIGN ENGINEER 6" (150 mm) MIN
*TO BOTTOM OF FLEXIBLE PAVEMENT. FOR UNPAVED
INSTALLATIONS WHERE RUTTING FROM VEHICLES MAY OCCUR,
INCREASE COVER TO 24" (600 mm).
EXCAVATION WALL
(CAN BE SLOPED OR VERTICAL)
PERIMETER STONE
(SEE NOTE 4)
SC-740 END CAP
SUBGRADE SOILS
(SEE NOTE 3)
PAVEMENT LAYER (DESIGNED
BY SITE DESIGN ENGINEER)
**THIS CROSS SECTION DETAIL REPRESENTS
MINIMUM REQUIREMENTS FOR INSTALLATION.
PLEASE SEE THE LAYOUT SHEET(S) FOR
PROJECT SPECIFIC REQUIREMENTS.
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INSPECTION & MAINTENANCE
STEP 1)INSPECT ISOLATOR ROW PLUS FOR SEDIMENT
A.INSPECTION PORTS (IF PRESENT)
A.1.REMOVE/OPEN LID ON NYLOPLAST INLINE DRAIN
A.2.REMOVE AND CLEAN FLEXSTORM FILTER IF INSTALLED
A.3.USING A FLASHLIGHT AND STADIA ROD, MEASURE DEPTH OF SEDIMENT AND RECORD ON MAINTENANCE LOG
A.4.LOWER A CAMERA INTO ISOLATOR ROW PLUS FOR VISUAL INSPECTION OF SEDIMENT LEVELS (OPTIONAL)
A.5.IF SEDIMENT IS AT, OR ABOVE, 3" (80 mm) PROCEED TO STEP 2. IF NOT, PROCEED TO STEP 3.
B.ALL ISOLATOR PLUS ROWS
B.1.REMOVE COVER FROM STRUCTURE AT UPSTREAM END OF ISOLATOR ROW PLUS
B.2.USING A FLASHLIGHT, INSPECT DOWN THE ISOLATOR ROW PLUS THROUGH OUTLET PIPE
i)MIRRORS ON POLES OR CAMERAS MAY BE USED TO AVOID A CONFINED SPACE ENTRY
ii)FOLLOW OSHA REGULATIONS FOR CONFINED SPACE ENTRY IF ENTERING MANHOLE
B.3.IF SEDIMENT IS AT, OR ABOVE, 3" (80 mm) PROCEED TO STEP 2. IF NOT, PROCEED TO STEP 3.
STEP 2)CLEAN OUT ISOLATOR ROW PLUS USING THE JETVAC PROCESS
A.A FIXED CULVERT CLEANING NOZZLE WITH REAR FACING SPREAD OF 45" (1.1 m) OR MORE IS PREFERRED
B.APPLY MULTIPLE PASSES OF JETVAC UNTIL BACKFLUSH WATER IS CLEAN
C.VACUUM STRUCTURE SUMP AS REQUIRED
STEP 3)REPLACE ALL COVERS, GRATES, FILTERS, AND LIDS; RECORD OBSERVATIONS AND ACTIONS.
STEP 4)INSPECT AND CLEAN BASINS AND MANHOLES UPSTREAM OF THE STORMTECH SYSTEM.
NOTES
1.INSPECT EVERY 6 MONTHS DURING THE FIRST YEAR OF OPERATION. ADJUST THE INSPECTION INTERVAL BASED ON PREVIOUS
OBSERVATIONS OF SEDIMENT ACCUMULATION AND HIGH WATER ELEVATIONS.
2.CONDUCT JETTING AND VACTORING ANNUALLY OR WHEN INSPECTION SHOWS THAT MAINTENANCE IS NECESSARY.
NOTE:
INSPECTION PORTS MAY BE CONNECTED THROUGH ANY CHAMBER CORRUGATION CREST.
STORMTECH CHAMBER
8" NYLOPLAST UNIVERSAL INLINE DRAIN
BODY (PART# 2708AG4IPKIT) OR TRAFFIC
RATED BOX W/SOLID LOCKING COVER
CONCRETE COLLAR
ASPHALT OVERLAY FOR
TRAFFIC APPLICATIONS
12" (300 mm) MIN WIDTH
8" (200 mm) MIN THICKNESS OF ASPHALT
OVERLAYAND CONCRETE COLLAR
4" PVC INSPECTION PORT DETAIL
(SC SERIES CHAMBER)
NTS
CONCRETE COLLAR / ASPHALT OVERLAY
NOT REQUIRED FOR GREENSPACE OR
NON-TRAFFIC APPLICATIONS
4" (100 mm) SDR 35 PIPE
4" (100 mm) INSERTA TEE
TO BE CENTERED ON CORRUGATION CREST
NYLOPLAST 8" LOCKING SOLID
COVER AND FRAME
SC-740 ISOLATOR ROW PLUS DETAIL
NTS
SC-740 END CAP
OPTIONAL INSPECTION PORT
SC-740 CHAMBER
ONE LAYER OF ADSPLUS625 WOVEN GEOTEXTILE BETWEEN
FOUNDATION STONE AND CHAMBERS
5' (1.5 m) MIN WIDE CONTINUOUS FABRIC WITHOUT SEAMS
ELEVATED BYPASS MANIFOLD
24" (600 mm) HDPE ACCESS PIPE REQUIRED
USE EZ END CAP PART #: SC740ECEZ
NYLOPLAST
SUMP DEPTH TBD BY
SITE DESIGN ENGINEER
(24" [600 mm] MIN RECOMMENDED)
STORMTECH HIGHLY RECOMMENDS
FLEXSTORM INSERTS IN ANY UPSTREAM
STRUCTURES WITH OPEN GRATES
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PART #STUB A B C
SC740EPE06T / SC740EPE06TPC 6" (150 mm)10.9" (277 mm)18.5" (470 mm)---
SC740EPE06B / SC740EPE06BPC ---0.5" (13 mm)
SC740EPE08T /SC740EPE08TPC 8" (200 mm)12.2" (310 mm)16.5" (419 mm)---
SC740EPE08B / SC740EPE08BPC ---0.6" (15 mm)
SC740EPE10T / SC740EPE10TPC 10" (250 mm)13.4" (340 mm)14.5" (368 mm)---
SC740EPE10B / SC740EPE10BPC ---0.7" (18 mm)
SC740EPE12T / SC740EPE12TPC 12" (300 mm)14.7" (373 mm)12.5" (318 mm)---
SC740EPE12B / SC740EPE12BPC ---1.2" (30 mm)
SC740EPE15T / SC740EPE15TPC 15" (375 mm)18.4" (467 mm)9.0" (229 mm)---
SC740EPE15B / SC740EPE15BPC ---1.3" (33 mm)
SC740EPE18T / SC740EPE18TPC 18" (450 mm)19.7" (500 mm)5.0" (127 mm)---
SC740EPE18B / SC740EPE18BPC ---1.6" (41 mm)
SC740ECEZ*24" (600 mm)18.5" (470 mm)---0.1" (3 mm)
ALL STUBS, EXCEPT FOR THE SC740ECEZ ARE PLACED AT BOTTOM OF END CAP SUCH THAT THE OUTSIDE DIAMETER OF THE
STUB IS FLUSH WITH THE BOTTOM OF THE END CAP. FOR ADDITIONAL INFORMATION CONTACT STORMTECH AT
1-888-892-2694.
* FOR THE SC740ECEZ THE 24" (600 mm) STUB LIES BELOW THE BOTTOM OF THE END CAP APPROXIMATELY 1.75" (44 mm).
BACKFILL MATERIAL SHOULD BE REMOVED FROM BELOW THE N-12 STUB SO THAT THE FITTING SITS LEVEL.
NOTE: ALL DIMENSIONS ARE NOMINAL
NOMINAL CHAMBER SPECIFICATIONS
SIZE (W X H X INSTALLED LENGTH)51.0" X 30.0" X 85.4" (1295 mm X 762 mm X 2169 mm)
CHAMBER STORAGE 45.9 CUBIC FEET (1.30 m³)
MINIMUM INSTALLED STORAGE*74.9 CUBIC FEET (2.12 m³)
WEIGHT 75.0 lbs.(33.6 kg)
*ASSUMES 6" (152 mm) STONE ABOVE, BELOW, AND BETWEEN CHAMBERS
PRE-FAB STUBS AT BOTTOM OF END CAP FOR PART NUMBERS ENDING WITH "B"
PRE-FAB STUBS AT TOP OF END CAP FOR PART NUMBERS ENDING WITH "T"
PRE-CORED END CAPS END WITH "PC"
SC-740 TECHNICAL SPECIFICATION
NTS
90.7" (2304 mm) ACTUAL LENGTH 85.4" (2169 mm) INSTALLED LENGTH
BUILD ROW IN THIS DIRECTION
A A
C
B
51.0"
(1295 mm)
30.0"
(762 mm)
45.9" (1166 mm)12.2"
(310 mm)
29.3"
(744 mm)
OVERLAP NEXT CHAMBER HERE
(OVER SMALL CORRUGATION)
START END
UNDERDRAIN DETAIL
NTS
A
A
B B
SECTION A-A
SECTION B-B
NUMBER AND SIZE OF UNDERDRAINS PER SITE DESIGN ENGINEER
4" (100 mm) TYP FOR SC-310 & SC-160LP SYSTEMS
6" (150 mm) TYP FOR SC-740, SC-800, DC-780, MC-3500, MC-4500 & MC-7200 SYSTEMS
OUTLET MANIFOLD
STORMTECH
END CAP
STORMTECH
CHAMBERS
STORMTECH
CHAMBER
STORMTECH
END CAP
DUAL WALL
PERFORATED
HDPE
UNDERDRAIN
ADS GEOSYNTHETICS 601T
NON-WOVEN GEOTEXTILE
ADS GEOSYNTHETICS 601T
NON-WOVEN GEOTEXTILE
FOUNDATION STONE
BENEATH CHAMBERS
FOUNDATION STONE
BENEATH CHAMBERS
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TRAFFIC LOADS: CONCRETE DIMENSIONS
ARE FOR GUIDELINE PUPOSES ONLY.
ACTUAL CONCRETE SLAB MUST BE
DESIGNED GIVING CONSIDERATION FOR
LOCAL SOIL CONDITIONS, TRAFFIC
LOADING & OTHER APPLICABLE DESIGN
FACTORS
ADAPTER ANGLES VARIABLE 0°- 360°
ACCORDING TO PLANS
A
18" (457 mm)
MIN WIDTH
AASHTO H-20 CONCRETE SLAB
8" (203 mm) MIN THICKNESS
VARIABLE SUMP DEPTH
ACCORDING TO PLANS
[6" (152 mm) MIN ON 8-24" (200-600 mm),
10" (254 mm) MIN ON 30" (750 mm)]
4" (102 mm) MIN ON 8-24" (200-600 mm)
6" (152 mm) MIN ON 30" (750 mm)
12" (610 mm) MIN
(FOR AASHTO H-20)
INVERT ACCORDING TO
PLANS/TAKE OFF
BACKFILL MATERIAL BELOW AND TO SIDES
OF STRUCTURE SHALL BE ASTM D2321
CLASS I OR II CRUSHED STONE OR GRAVEL
AND BE PLACED UNIFORMLY IN 12" (305 mm)
LIFTS AND COMPACTED TO MIN OF 90%
INTEGRATED DUCTILE IRON
FRAME & GRATE/SOLID TO
MATCH BASIN O.D.
NYLOPLAST DRAIN BASIN
NTS
NOTES
1.8-30" (200-750 mm) GRATES/SOLID COVERS SHALL BE DUCTILE IRON PER ASTM A536
GRADE 70-50-05
2.12-30" (300-750 mm) FRAMES SHALL BE DUCTILE IRON PER ASTM A536 GRADE 70-50-05
3.DRAIN BASIN TO BE CUSTOM MANUFACTURED ACCORDING TO PLAN DETAILS
4.DRAINAGE CONNECTION STUB JOINT TIGHTNESS SHALL CONFORM TO ASTM D3212
FOR CORRUGATED HDPE (ADS & HANCOR DUAL WALL) & SDR 35 PVC
5.FOR COMPLETE DESIGN AND PRODUCT INFORMATION: WWW.NYLOPLAST-US.COM
6.TO ORDER CALL: 800-821-6710
A PART #GRATE/SOLID COVER OPTIONS
8"
(200 mm)2808AG PEDESTRIAN LIGHT
DUTY
STANDARD LIGHT
DUTY SOLID LIGHT DUTY
10"
(250 mm)2810AG PEDESTRIAN LIGHT
DUTY
STANDARD LIGHT
DUTY SOLID LIGHT DUTY
12"
(300 mm)2812AG PEDESTRIAN
AASHTO H-10
STANDARD AASHTO
H-20
SOLID
AASHTO H-20
15"
(375 mm)2815AG PEDESTRIAN
AASHTO H-10
STANDARD AASHTO
H-20
SOLID
AASHTO H-20
18"
(450 mm)2818AG PEDESTRIAN
AASHTO H-10
STANDARD AASHTO
H-20
SOLID
AASHTO H-20
24"
(600 mm)2824AG PEDESTRIAN
AASHTO H-10
STANDARD AASHTO
H-20
SOLID
AASHTO H-20
30"
(750 mm)2830AG PEDESTRIAN
AASHTO H-20
STANDARD AASHTO
H-20
SOLID
AASHTO H-20
VARIOUS TYPES OF INLET AND
OUTLET ADAPTERS AVAILABLE:
4-30" (100-750 mm) FOR
CORRUGATED HDPE
WATERTIGHT JOINT
(CORRUGATED HDPE SHOWN)
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NORTH SYSTEM SOUTH SYSTEM
D
APPENDIX D – USDA SOILS REPORT
United States
Department of
Agriculture
A product of the National
Cooperative Soil Survey,
a joint effort of the United
States Department of
Agriculture and other
Federal agencies, State
agencies including the
Agricultural Experiment
Stations, and local
participants
Custom Soil Resource
Report for
Larimer County
Area, ColoradoNatural
Resources
Conservation
Service
January 31, 2023
Preface
Soil surveys contain information that affects land use planning in survey areas.
They highlight soil limitations that affect various land uses and provide information
about the properties of the soils in the survey areas. Soil surveys are designed for
many different users, including farmers, ranchers, foresters, agronomists, urban
planners, community officials, engineers, developers, builders, and home buyers.
Also, conservationists, teachers, students, and specialists in recreation, waste
disposal, and pollution control can use the surveys to help them understand,
protect, or enhance the environment.
Various land use regulations of Federal, State, and local governments may impose
special restrictions on land use or land treatment. Soil surveys identify soil
properties that are used in making various land use or land treatment decisions.
The information is intended to help the land users identify and reduce the effects of
soil limitations on various land uses. The landowner or user is responsible for
identifying and complying with existing laws and regulations.
Although soil survey information can be used for general farm, local, and wider area
planning, onsite investigation is needed to supplement this information in some
cases. Examples include soil quality assessments (http://www.nrcs.usda.gov/wps/
portal/nrcs/main/soils/health/) and certain conservation and engineering
applications. For more detailed information, contact your local USDA Service Center
(https://offices.sc.egov.usda.gov/locator/app?agency=nrcs) or your NRCS State Soil
Scientist (http://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/contactus/?
cid=nrcs142p2_053951).
Great differences in soil properties can occur within short distances. Some soils are
seasonally wet or subject to flooding. Some are too unstable to be used as a
foundation for buildings or roads. Clayey or wet soils are poorly suited to use as
septic tank absorption fields. A high water table makes a soil poorly suited to
basements or underground installations.
The National Cooperative Soil Survey is a joint effort of the United States
Department of Agriculture and other Federal agencies, State agencies including the
Agricultural Experiment Stations, and local agencies. The Natural Resources
Conservation Service (NRCS) has leadership for the Federal part of the National
Cooperative Soil Survey.
Information about soils is updated periodically. Updated information is available
through the NRCS Web Soil Survey, the site for official soil survey information.
The U.S. Department of Agriculture (USDA) prohibits discrimination in all its
programs and activities on the basis of race, color, national origin, age, disability,
and where applicable, sex, marital status, familial status, parental status, religion,
sexual orientation, genetic information, political beliefs, reprisal, or because all or a
part of an individual's income is derived from any public assistance program. (Not
all prohibited bases apply to all programs.) Persons with disabilities who require
2
alternative means for communication of program information (Braille, large print,
audiotape, etc.) should contact USDA's TARGET Center at (202) 720-2600 (voice
and TDD). To file a complaint of discrimination, write to USDA, Director, Office of
Civil Rights, 1400 Independence Avenue, S.W., Washington, D.C. 20250-9410 or
call (800) 795-3272 (voice) or (202) 720-6382 (TDD). USDA is an equal opportunity
provider and employer.
3
Contents
Preface....................................................................................................................2
How Soil Surveys Are Made..................................................................................5
Soil Map..................................................................................................................8
Soil Map................................................................................................................9
Legend................................................................................................................10
Map Unit Legend................................................................................................11
Map Unit Descriptions.........................................................................................11
Larimer County Area, Colorado......................................................................13
22—Caruso clay loam, 0 to 1 percent slope...............................................13
35—Fort Collins loam, 0 to 3 percent slopes..............................................14
64—Loveland clay loam, 0 to 1 percent slopes...........................................15
76—Nunn clay loam, wet, 1 to 3 percent slopes.........................................16
105—Table Mountain loam, 0 to 1 percent slopes......................................18
Soil Information for All Uses...............................................................................20
Soil Properties and Qualities..............................................................................20
Soil Erosion Factors........................................................................................20
K Factor, Whole Soil....................................................................................20
References............................................................................................................24
4
How Soil Surveys Are Made
Soil surveys are made to provide information about the soils and miscellaneous
areas in a specific area. They include a description of the soils and miscellaneous
areas and their location on the landscape and tables that show soil properties and
limitations affecting various uses. Soil scientists observed the steepness, length,
and shape of the slopes; the general pattern of drainage; the kinds of crops and
native plants; and the kinds of bedrock. They observed and described many soil
profiles. A soil profile is the sequence of natural layers, or horizons, in a soil. The
profile extends from the surface down into the unconsolidated material in which the
soil formed or from the surface down to bedrock. The unconsolidated material is
devoid of roots and other living organisms and has not been changed by other
biological activity.
Currently, soils are mapped according to the boundaries of major land resource
areas (MLRAs). MLRAs are geographically associated land resource units that
share common characteristics related to physiography, geology, climate, water
resources, soils, biological resources, and land uses (USDA, 2006). Soil survey
areas typically consist of parts of one or more MLRA.
The soils and miscellaneous areas in a survey area occur in an orderly pattern that
is related to the geology, landforms, relief, climate, and natural vegetation of the
area. Each kind of soil and miscellaneous area is associated with a particular kind
of landform or with a segment of the landform. By observing the soils and
miscellaneous areas in the survey area and relating their position to specific
segments of the landform, a soil scientist develops a concept, or model, of how they
were formed. Thus, during mapping, this model enables the soil scientist to predict
with a considerable degree of accuracy the kind of soil or miscellaneous area at a
specific location on the landscape.
Commonly, individual soils on the landscape merge into one another as their
characteristics gradually change. To construct an accurate soil map, however, soil
scientists must determine the boundaries between the soils. They can observe only
a limited number of soil profiles. Nevertheless, these observations, supplemented
by an understanding of the soil-vegetation-landscape relationship, are sufficient to
verify predictions of the kinds of soil in an area and to determine the boundaries.
Soil scientists recorded the characteristics of the soil profiles that they studied. They
noted soil color, texture, size and shape of soil aggregates, kind and amount of rock
fragments, distribution of plant roots, reaction, and other features that enable them
to identify soils. After describing the soils in the survey area and determining their
properties, the soil scientists assigned the soils to taxonomic classes (units).
Taxonomic classes are concepts. Each taxonomic class has a set of soil
characteristics with precisely defined limits. The classes are used as a basis for
comparison to classify soils systematically. Soil taxonomy, the system of taxonomic
classification used in the United States, is based mainly on the kind and character
of soil properties and the arrangement of horizons within the profile. After the soil
5
scientists classified and named the soils in the survey area, they compared the
individual soils with similar soils in the same taxonomic class in other areas so that
they could confirm data and assemble additional data based on experience and
research.
The objective of soil mapping is not to delineate pure map unit components; the
objective is to separate the landscape into landforms or landform segments that
have similar use and management requirements. Each map unit is defined by a
unique combination of soil components and/or miscellaneous areas in predictable
proportions. Some components may be highly contrasting to the other components
of the map unit. The presence of minor components in a map unit in no way
diminishes the usefulness or accuracy of the data. The delineation of such
landforms and landform segments on the map provides sufficient information for the
development of resource plans. If intensive use of small areas is planned, onsite
investigation is needed to define and locate the soils and miscellaneous areas.
Soil scientists make many field observations in the process of producing a soil map.
The frequency of observation is dependent upon several factors, including scale of
mapping, intensity of mapping, design of map units, complexity of the landscape,
and experience of the soil scientist. Observations are made to test and refine the
soil-landscape model and predictions and to verify the classification of the soils at
specific locations. Once the soil-landscape model is refined, a significantly smaller
number of measurements of individual soil properties are made and recorded.
These measurements may include field measurements, such as those for color,
depth to bedrock, and texture, and laboratory measurements, such as those for
content of sand, silt, clay, salt, and other components. Properties of each soil
typically vary from one point to another across the landscape.
Observations for map unit components are aggregated to develop ranges of
characteristics for the components. The aggregated values are presented. Direct
measurements do not exist for every property presented for every map unit
component. Values for some properties are estimated from combinations of other
properties.
While a soil survey is in progress, samples of some of the soils in the area generally
are collected for laboratory analyses and for engineering tests. Soil scientists
interpret the data from these analyses and tests as well as the field-observed
characteristics and the soil properties to determine the expected behavior of the
soils under different uses. Interpretations for all of the soils are field tested through
observation of the soils in different uses and under different levels of management.
Some interpretations are modified to fit local conditions, and some new
interpretations are developed to meet local needs. Data are assembled from other
sources, such as research information, production records, and field experience of
specialists. For example, data on crop yields under defined levels of management
are assembled from farm records and from field or plot experiments on the same
kinds of soil.
Predictions about soil behavior are based not only on soil properties but also on
such variables as climate and biological activity. Soil conditions are predictable over
long periods of time, but they are not predictable from year to year. For example,
soil scientists can predict with a fairly high degree of accuracy that a given soil will
have a high water table within certain depths in most years, but they cannot predict
that a high water table will always be at a specific level in the soil on a specific date.
After soil scientists located and identified the significant natural bodies of soil in the
survey area, they drew the boundaries of these bodies on aerial photographs and
Custom Soil Resource Report
6
identified each as a specific map unit. Aerial photographs show trees, buildings,
fields, roads, and rivers, all of which help in locating boundaries accurately.
Custom Soil Resource Report
7
Soil Map
The soil map section includes the soil map for the defined area of interest, a list of
soil map units on the map and extent of each map unit, and cartographic symbols
displayed on the map. Also presented are various metadata about data used to
produce the map, and a description of each soil map unit.
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Custom Soil Resource Report
Soil Map
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495200 495300 495400 495500 495600 495700 495800
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Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 13N WGS84
0 200 400 800 1200
Feet
0 50 100 200 300
Meters
Map Scale: 1:4,750 if printed on A portrait (8.5" x 11") sheet.
Soil Map may not be valid at this scale.
MAP LEGEND MAP INFORMATION
Area of Interest (AOI)
Area of Interest (AOI)
Soils
Soil Map Unit Polygons
Soil Map Unit Lines
Soil Map Unit Points
Special Point Features
Blowout
Borrow Pit
Clay Spot
Closed Depression
Gravel Pit
Gravelly Spot
Landfill
Lava Flow
Marsh or swamp
Mine or Quarry
Miscellaneous Water
Perennial Water
Rock Outcrop
Saline Spot
Sandy Spot
Severely Eroded Spot
Sinkhole
Slide or Slip
Sodic Spot
Spoil Area
Stony Spot
Very Stony Spot
Wet Spot
Other
Special Line Features
Water Features
Streams and Canals
Transportation
Rails
Interstate Highways
US Routes
Major Roads
Local Roads
Background
Aerial Photography
The soil surveys that comprise your AOI were mapped at
1:24,000.
Warning: Soil Map may not be valid at this scale.
Enlargement of maps beyond the scale of mapping can cause
misunderstanding of the detail of mapping and accuracy of soil
line placement. The maps do not show the small areas of
contrasting soils that could have been shown at a more detailed
scale.
Please rely on the bar scale on each map sheet for map
measurements.
Source of Map: Natural Resources Conservation Service
Web Soil Survey URL:
Coordinate System: Web Mercator (EPSG:3857)
Maps from the Web Soil Survey are based on the Web Mercator
projection, which preserves direction and shape but distorts
distance and area. A projection that preserves area, such as the
Albers equal-area conic projection, should be used if more
accurate calculations of distance or area are required.
This product is generated from the USDA-NRCS certified data as
of the version date(s) listed below.
Soil Survey Area: Larimer County Area, Colorado
Survey Area Data: Version 17, Sep 7, 2022
Soil map units are labeled (as space allows) for map scales
1:50,000 or larger.
Date(s) aerial images were photographed: Jul 2, 2021—Aug 25,
2021
The orthophoto or other base map on which the soil lines were
compiled and digitized probably differs from the background
imagery displayed on these maps. As a result, some minor
shifting of map unit boundaries may be evident.
Custom Soil Resource Report
10
Map Unit Legend
Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI
22 Caruso clay loam, 0 to 1
percent slope
53.1 52.9%
35 Fort Collins loam, 0 to 3 percent
slopes
14.4 14.4%
64 Loveland clay loam, 0 to 1
percent slopes
10.2 10.2%
76 Nunn clay loam, wet, 1 to 3
percent slopes
18.6 18.5%
105 Table Mountain loam, 0 to 1
percent slopes
4.0 4.0%
Totals for Area of Interest 100.2 100.0%
Map Unit Descriptions
The map units delineated on the detailed soil maps in a soil survey represent the
soils or miscellaneous areas in the survey area. The map unit descriptions, along
with the maps, can be used to determine the composition and properties of a unit.
A map unit delineation on a soil map represents an area dominated by one or more
major kinds of soil or miscellaneous areas. A map unit is identified and named
according to the taxonomic classification of the dominant soils. Within a taxonomic
class there are precisely defined limits for the properties of the soils. On the
landscape, however, the soils are natural phenomena, and they have the
characteristic variability of all natural phenomena. Thus, the range of some
observed properties may extend beyond the limits defined for a taxonomic class.
Areas of soils of a single taxonomic class rarely, if ever, can be mapped without
including areas of other taxonomic classes. Consequently, every map unit is made
up of the soils or miscellaneous areas for which it is named and some minor
components that belong to taxonomic classes other than those of the major soils.
Most minor soils have properties similar to those of the dominant soil or soils in the
map unit, and thus they do not affect use and management. These are called
noncontrasting, or similar, components. They may or may not be mentioned in a
particular map unit description. Other minor components, however, have properties
and behavioral characteristics divergent enough to affect use or to require different
management. These are called contrasting, or dissimilar, components. They
generally are in small areas and could not be mapped separately because of the
scale used. Some small areas of strongly contrasting soils or miscellaneous areas
are identified by a special symbol on the maps. If included in the database for a
given area, the contrasting minor components are identified in the map unit
descriptions along with some characteristics of each. A few areas of minor
components may not have been observed, and consequently they are not
mentioned in the descriptions, especially where the pattern was so complex that it
was impractical to make enough observations to identify all the soils and
miscellaneous areas on the landscape.
Custom Soil Resource Report
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The presence of minor components in a map unit in no way diminishes the
usefulness or accuracy of the data. The objective of mapping is not to delineate
pure taxonomic classes but rather to separate the landscape into landforms or
landform segments that have similar use and management requirements. The
delineation of such segments on the map provides sufficient information for the
development of resource plans. If intensive use of small areas is planned, however,
onsite investigation is needed to define and locate the soils and miscellaneous
areas.
An identifying symbol precedes the map unit name in the map unit descriptions.
Each description includes general facts about the unit and gives important soil
properties and qualities.
Soils that have profiles that are almost alike make up a soil series. Except for
differences in texture of the surface layer, all the soils of a series have major
horizons that are similar in composition, thickness, and arrangement.
Soils of one series can differ in texture of the surface layer, slope, stoniness,
salinity, degree of erosion, and other characteristics that affect their use. On the
basis of such differences, a soil series is divided into soil phases. Most of the areas
shown on the detailed soil maps are phases of soil series. The name of a soil phase
commonly indicates a feature that affects use or management. For example, Alpha
silt loam, 0 to 2 percent slopes, is a phase of the Alpha series.
Some map units are made up of two or more major soils or miscellaneous areas.
These map units are complexes, associations, or undifferentiated groups.
A complex consists of two or more soils or miscellaneous areas in such an intricate
pattern or in such small areas that they cannot be shown separately on the maps.
The pattern and proportion of the soils or miscellaneous areas are somewhat similar
in all areas. Alpha-Beta complex, 0 to 6 percent slopes, is an example.
An association is made up of two or more geographically associated soils or
miscellaneous areas that are shown as one unit on the maps. Because of present
or anticipated uses of the map units in the survey area, it was not considered
practical or necessary to map the soils or miscellaneous areas separately. The
pattern and relative proportion of the soils or miscellaneous areas are somewhat
similar. Alpha-Beta association, 0 to 2 percent slopes, is an example.
An undifferentiated group is made up of two or more soils or miscellaneous areas
that could be mapped individually but are mapped as one unit because similar
interpretations can be made for use and management. The pattern and proportion
of the soils or miscellaneous areas in a mapped area are not uniform. An area can
be made up of only one of the major soils or miscellaneous areas, or it can be made
up of all of them. Alpha and Beta soils, 0 to 2 percent slopes, is an example.
Some surveys include miscellaneous areas. Such areas have little or no soil
material and support little or no vegetation. Rock outcrop is an example.
Custom Soil Resource Report
12
Larimer County Area, Colorado
22—Caruso clay loam, 0 to 1 percent slope
Map Unit Setting
National map unit symbol: jpvt
Elevation: 4,800 to 5,500 feet
Mean annual precipitation: 13 to 15 inches
Mean annual air temperature: 48 to 50 degrees F
Frost-free period: 135 to 150 days
Farmland classification: Prime farmland if irrigated
Map Unit Composition
Caruso and similar soils:85 percent
Minor components:15 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
Description of Caruso
Setting
Landform:Flood-plain steps, stream terraces
Landform position (three-dimensional):Tread
Down-slope shape:Linear
Across-slope shape:Linear
Parent material:Mixed alluvium
Typical profile
H1 - 0 to 35 inches: clay loam
H2 - 35 to 44 inches: fine sandy loam
H3 - 44 to 60 inches: gravelly sand
Properties and qualities
Slope:0 to 1 percent
Depth to restrictive feature:More than 80 inches
Drainage class:Somewhat poorly drained
Runoff class: High
Capacity of the most limiting layer to transmit water (Ksat):Moderately low to
moderately high (0.06 to 0.20 in/hr)
Depth to water table:About 24 to 48 inches
Frequency of flooding:NoneOccasional
Frequency of ponding:None
Calcium carbonate, maximum content:5 percent
Maximum salinity:Nonsaline to very slightly saline (0.0 to 2.0 mmhos/cm)
Available water supply, 0 to 60 inches: Moderate (about 8.4 inches)
Interpretive groups
Land capability classification (irrigated): 3w
Land capability classification (nonirrigated): 5w
Hydrologic Soil Group: D
Ecological site: R067BY036CO - Overflow
Hydric soil rating: No
Minor Components
Loveland
Percent of map unit:9 percent
Custom Soil Resource Report
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Landform:Terraces
Ecological site:R067BY036CO - Overflow
Hydric soil rating: Yes
Fluvaquents
Percent of map unit:6 percent
Landform:Terraces
Hydric soil rating: Yes
35—Fort Collins loam, 0 to 3 percent slopes
Map Unit Setting
National map unit symbol: 2tlnc
Elevation: 4,020 to 6,730 feet
Mean annual precipitation: 14 to 16 inches
Mean annual air temperature: 46 to 48 degrees F
Frost-free period: 135 to 160 days
Farmland classification: Prime farmland if irrigated
Map Unit Composition
Fort collins and similar soils:85 percent
Minor components:15 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
Description of Fort Collins
Setting
Landform:Stream terraces, interfluves
Landform position (three-dimensional):Interfluve, tread
Down-slope shape:Linear
Across-slope shape:Linear
Parent material:Pleistocene or older alluvium and/or eolian deposits
Typical profile
Ap - 0 to 4 inches: loam
Bt1 - 4 to 9 inches: clay loam
Bt2 - 9 to 16 inches: clay loam
Bk1 - 16 to 29 inches: loam
Bk2 - 29 to 80 inches: loam
Properties and qualities
Slope:0 to 3 percent
Depth to restrictive feature:More than 80 inches
Drainage class:Well drained
Runoff class: Low
Capacity of the most limiting layer to transmit water (Ksat):Moderately high to high
(0.20 to 2.00 in/hr)
Depth to water table:More than 80 inches
Frequency of flooding:None
Frequency of ponding:None
Calcium carbonate, maximum content:12 percent
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Maximum salinity:Nonsaline to very slightly saline (0.1 to 2.0 mmhos/cm)
Available water supply, 0 to 60 inches: High (about 9.1 inches)
Interpretive groups
Land capability classification (irrigated): 3e
Land capability classification (nonirrigated): 3e
Hydrologic Soil Group: C
Ecological site: R067BY002CO - Loamy Plains
Hydric soil rating: No
Minor Components
Nunn
Percent of map unit:10 percent
Landform:Stream terraces
Landform position (three-dimensional):Tread
Down-slope shape:Linear
Across-slope shape:Linear
Ecological site:R067BY002CO - Loamy Plains
Hydric soil rating: No
Vona
Percent of map unit:5 percent
Landform:Interfluves
Landform position (three-dimensional):Interfluve, side slope
Down-slope shape:Linear
Across-slope shape:Linear
Ecological site:R067BY024CO - Sandy Plains
Hydric soil rating: No
64—Loveland clay loam, 0 to 1 percent slopes
Map Unit Setting
National map unit symbol: jpx9
Elevation: 4,800 to 5,500 feet
Mean annual precipitation: 13 to 15 inches
Mean annual air temperature: 48 to 50 degrees F
Frost-free period: 135 to 150 days
Farmland classification: Prime farmland if irrigated
Map Unit Composition
Loveland and similar soils:90 percent
Minor components:10 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
Description of Loveland
Setting
Landform:Flood plains, stream terraces
Landform position (three-dimensional):Tread
Down-slope shape:Linear
Custom Soil Resource Report
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Across-slope shape:Linear
Parent material:Alluvium
Typical profile
H1 - 0 to 15 inches: clay loam
H2 - 15 to 32 inches: loam
H3 - 32 to 60 inches: very gravelly sand
Properties and qualities
Slope:0 to 1 percent
Depth to restrictive feature:More than 80 inches
Drainage class:Poorly drained
Runoff class: Medium
Capacity of the most limiting layer to transmit water (Ksat):Moderately high (0.20
to 0.60 in/hr)
Depth to water table:About 18 to 36 inches
Frequency of flooding:OccasionalNone
Frequency of ponding:None
Calcium carbonate, maximum content:15 percent
Maximum salinity:Very slightly saline to slightly saline (2.0 to 4.0 mmhos/cm)
Available water supply, 0 to 60 inches: Moderate (about 7.5 inches)
Interpretive groups
Land capability classification (irrigated): 3w
Land capability classification (nonirrigated): 3w
Hydrologic Soil Group: C
Ecological site: R067BY036CO - Overflow
Hydric soil rating: No
Minor Components
Aquolls
Percent of map unit:5 percent
Landform:Swales
Hydric soil rating: Yes
Poudre
Percent of map unit:5 percent
Ecological site:R067BY036CO - Overflow
Hydric soil rating: No
76—Nunn clay loam, wet, 1 to 3 percent slopes
Map Unit Setting
National map unit symbol: jpxq
Elevation: 4,800 to 5,600 feet
Mean annual precipitation: 13 to 15 inches
Mean annual air temperature: 48 to 50 degrees F
Frost-free period: 135 to 150 days
Farmland classification: Prime farmland if irrigated
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Map Unit Composition
Nunn, wet, and similar soils:90 percent
Minor components:10 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
Description of Nunn, Wet
Setting
Landform:Alluvial fans, stream terraces
Landform position (three-dimensional):Base slope, tread
Down-slope shape:Linear
Across-slope shape:Linear
Parent material:Alluvium
Typical profile
H1 - 0 to 10 inches: clay loam
H2 - 10 to 47 inches: clay
H3 - 47 to 60 inches: gravelly loam
Properties and qualities
Slope:1 to 3 percent
Depth to restrictive feature:More than 80 inches
Drainage class:Somewhat poorly drained
Runoff class: Medium
Capacity of the most limiting layer to transmit water (Ksat):Moderately low to
moderately high (0.06 to 0.60 in/hr)
Depth to water table:About 24 to 36 inches
Frequency of flooding:NoneRare
Frequency of ponding:None
Calcium carbonate, maximum content:10 percent
Maximum salinity:Nonsaline to very slightly saline (0.0 to 2.0 mmhos/cm)
Available water supply, 0 to 60 inches: High (about 9.9 inches)
Interpretive groups
Land capability classification (irrigated): 2w
Land capability classification (nonirrigated): 3s
Hydrologic Soil Group: C
Ecological site: R067BY038CO - Wet Meadow
Hydric soil rating: No
Minor Components
Heldt
Percent of map unit:6 percent
Ecological site:R067BY042CO - Clayey Plains
Hydric soil rating: No
Dacono
Percent of map unit:3 percent
Ecological site:R067BY042CO - Clayey Plains
Hydric soil rating: No
Mollic halaquepts
Percent of map unit:1 percent
Landform:Swales
Hydric soil rating: Yes
Custom Soil Resource Report
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105—Table Mountain loam, 0 to 1 percent slopes
Map Unit Setting
National map unit symbol: jpty
Elevation: 4,800 to 5,600 feet
Mean annual precipitation: 13 to 15 inches
Mean annual air temperature: 48 to 50 degrees F
Frost-free period: 135 to 150 days
Farmland classification: Prime farmland if irrigated
Map Unit Composition
Table mountain and similar soils:85 percent
Minor components:15 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
Description of Table Mountain
Setting
Landform:Flood plains, stream terraces
Landform position (three-dimensional):Tread
Down-slope shape:Linear
Across-slope shape:Linear
Parent material:Alluvium
Typical profile
H1 - 0 to 36 inches: loam
H2 - 36 to 60 inches: clay loam
Properties and qualities
Slope:0 to 1 percent
Depth to restrictive feature:More than 80 inches
Drainage class:Well drained
Runoff class: Low
Capacity of the most limiting layer to transmit water (Ksat):Moderately high to high
(0.60 to 2.00 in/hr)
Depth to water table:More than 80 inches
Frequency of flooding:None
Frequency of ponding:None
Calcium carbonate, maximum content:15 percent
Maximum salinity:Nonsaline to very slightly saline (0.0 to 2.0 mmhos/cm)
Sodium adsorption ratio, maximum:5.0
Available water supply, 0 to 60 inches: High (about 9.8 inches)
Interpretive groups
Land capability classification (irrigated): 1
Land capability classification (nonirrigated): 3c
Hydrologic Soil Group: B
Ecological site: R049XY036CO - Overflow
Hydric soil rating: No
Custom Soil Resource Report
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Minor Components
Caruso
Percent of map unit:7 percent
Hydric soil rating: No
Fluvaquentic haplustolls
Percent of map unit:4 percent
Landform:Terraces
Hydric soil rating: Yes
Paoli
Percent of map unit:4 percent
Hydric soil rating: No
Custom Soil Resource Report
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Soil Information for All Uses
Soil Properties and Qualities
The Soil Properties and Qualities section includes various soil properties and
qualities displayed as thematic maps with a summary table for the soil map units in
the selected area of interest. A single value or rating for each map unit is generated
by aggregating the interpretive ratings of individual map unit components. This
aggregation process is defined for each property or quality.
Soil Erosion Factors
Soil Erosion Factors are soil properties and interpretations used in evaluating the
soil for potential erosion. Example soil erosion factors can include K factor for the
whole soil or on a rock free basis, T factor, wind erodibility group and wind erodibility
index.
K Factor, Whole Soil
Erosion factor K indicates the susceptibility of a soil to sheet and rill erosion by
water. Factor K is one of six factors used in the Universal Soil Loss Equation
(USLE) and the Revised Universal Soil Loss Equation (RUSLE) to predict the
average annual rate of soil loss by sheet and rill erosion in tons per acre per year.
The estimates are based primarily on percentage of silt, sand, and organic matter
and on soil structure and saturated hydraulic conductivity (Ksat). Values of K range
from 0.02 to 0.69. Other factors being equal, the higher the value, the more
susceptible the soil is to sheet and rill erosion by water.
"Erosion factor Kw (whole soil)" indicates the erodibility of the whole soil. The
estimates are modified by the presence of rock fragments.
Factor K does not apply to organic horizons and is not reported for those layers.
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Custom Soil Resource Report
Map—K Factor, Whole Soil
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Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 13N WGS84
0 200 400 800 1200
Feet
0 50 100 200 300
Meters
Map Scale: 1:4,750 if printed on A portrait (8.5" x 11") sheet.
Soil Map may not be valid at this scale.
MAP LEGEND MAP INFORMATION
Area of Interest (AOI)
Area of Interest (AOI)
Soils
Soil Rating Polygons
.02
.05
.10
.15
.17
.20
.24
.28
.32
.37
.43
.49
.55
.64
Not rated or not available
Soil Rating Lines
.02
.05
.10
.15
.17
.20
.24
.28
.32
.37
.43
.49
.55
.64
Not rated or not available
Soil Rating Points
.02
.05
.10
.15
.17
.20
.24
.28
.32
.37
.43
.49
.55
.64
Not rated or not available
Water Features
Streams and Canals
Transportation
Rails
Interstate Highways
US Routes
Major Roads
Local Roads
Background
Aerial Photography
The soil surveys that comprise your AOI were mapped at
1:24,000.
Warning: Soil Map may not be valid at this scale.
Enlargement of maps beyond the scale of mapping can cause
misunderstanding of the detail of mapping and accuracy of soil
line placement. The maps do not show the small areas of
contrasting soils that could have been shown at a more detailed
scale.
Please rely on the bar scale on each map sheet for map
measurements.
Source of Map: Natural Resources Conservation Service
Web Soil Survey URL:
Coordinate System: Web Mercator (EPSG:3857)
Maps from the Web Soil Survey are based on the Web Mercator
projection, which preserves direction and shape but distorts
distance and area. A projection that preserves area, such as the
Albers equal-area conic projection, should be used if more
accurate calculations of distance or area are required.
This product is generated from the USDA-NRCS certified data
as of the version date(s) listed below.
Soil Survey Area: Larimer County Area, Colorado
Survey Area Data: Version 17, Sep 7, 2022
Soil map units are labeled (as space allows) for map scales
1:50,000 or larger.
Date(s) aerial images were photographed: Jul 2, 2021—Aug
25, 2021
The orthophoto or other base map on which the soil lines were
compiled and digitized probably differs from the background
imagery displayed on these maps. As a result, some minor
shifting of map unit boundaries may be evident.
Custom Soil Resource Report
22
Table—K Factor, Whole Soil
Map unit symbol Map unit name Rating Acres in AOI Percent of AOI
22 Caruso clay loam, 0 to 1
percent slope
.32 53.1 52.9%
35 Fort Collins loam, 0 to 3
percent slopes
.43 14.4 14.4%
64 Loveland clay loam, 0 to
1 percent slopes
.20 10.2 10.2%
76 Nunn clay loam, wet, 1 to
3 percent slopes
.24 18.6 18.5%
105 Table Mountain loam, 0
to 1 percent slopes
.37 4.0 4.0%
Totals for Area of Interest 100.2 100.0%
Rating Options—K Factor, Whole Soil
Aggregation Method: Dominant Condition
Component Percent Cutoff: None Specified
Tie-break Rule: Higher
Layer Options (Horizon Aggregation Method): Surface Layer (Not applicable)
Custom Soil Resource Report
23
References
American Association of State Highway and Transportation Officials (AASHTO).
2004. Standard specifications for transportation materials and methods of sampling
and testing. 24th edition.
American Society for Testing and Materials (ASTM). 2005. Standard classification of
soils for engineering purposes. ASTM Standard D2487-00.
Cowardin, L.M., V. Carter, F.C. Golet, and E.T. LaRoe. 1979. Classification of
wetlands and deep-water habitats of the United States. U.S. Fish and Wildlife
Service FWS/OBS-79/31.
Federal Register. July 13, 1994. Changes in hydric soils of the United States.
Federal Register. September 18, 2002. Hydric soils of the United States.
Hurt, G.W., and L.M. Vasilas, editors. Version 6.0, 2006. Field indicators of hydric
soils in the United States.
National Research Council. 1995. Wetlands: Characteristics and boundaries.
Soil Survey Division Staff. 1993. Soil survey manual. Soil Conservation Service.
U.S. Department of Agriculture Handbook 18. http://www.nrcs.usda.gov/wps/portal/
nrcs/detail/national/soils/?cid=nrcs142p2_054262
Soil Survey Staff. 1999. Soil taxonomy: A basic system of soil classification for
making and interpreting soil surveys. 2nd edition. Natural Resources Conservation
Service, U.S. Department of Agriculture Handbook 436. http://
www.nrcs.usda.gov/wps/portal/nrcs/detail/national/soils/?cid=nrcs142p2_053577
Soil Survey Staff. 2010. Keys to soil taxonomy. 11th edition. U.S. Department of
Agriculture, Natural Resources Conservation Service. http://
www.nrcs.usda.gov/wps/portal/nrcs/detail/national/soils/?cid=nrcs142p2_053580
Tiner, R.W., Jr. 1985. Wetlands of Delaware. U.S. Fish and Wildlife Service and
Delaware Department of Natural Resources and Environmental Control, Wetlands
Section.
United States Army Corps of Engineers, Environmental Laboratory. 1987. Corps of
Engineers wetlands delineation manual. Waterways Experiment Station Technical
Report Y-87-1.
United States Department of Agriculture, Natural Resources Conservation Service.
National forestry manual. http://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/
home/?cid=nrcs142p2_053374
United States Department of Agriculture, Natural Resources Conservation Service.
National range and pasture handbook. http://www.nrcs.usda.gov/wps/portal/nrcs/
detail/national/landuse/rangepasture/?cid=stelprdb1043084
24
United States Department of Agriculture, Natural Resources Conservation Service.
National soil survey handbook, title 430-VI. http://www.nrcs.usda.gov/wps/portal/
nrcs/detail/soils/scientists/?cid=nrcs142p2_054242
United States Department of Agriculture, Natural Resources Conservation Service.
2006. Land resource regions and major land resource areas of the United States,
the Caribbean, and the Pacific Basin. U.S. Department of Agriculture Handbook
296. http://www.nrcs.usda.gov/wps/portal/nrcs/detail/national/soils/?
cid=nrcs142p2_053624
United States Department of Agriculture, Soil Conservation Service. 1961. Land
capability classification. U.S. Department of Agriculture Handbook 210. http://
www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/nrcs142p2_052290.pdf
Custom Soil Resource Report
25
E
APPENDIX E – FEMA FIRMETTE
National Flood Hazard Layer FIRMette
0 500 1,000 1,500 2,000250
Feet
Ü
SEE FIS REPORT FOR DETAILED LEGEND AND INDEX MAP FOR FIRM PANEL LAYOUT
SPECIAL FLOOD
HAZARD AREAS
Without Base Flood Elevation (BFE)
Zone A, V, A99
With BFE or DepthZone AE, AO, AH, VE, AR
Regulatory Floodway
0.2% Annual Chance Flood Hazard, Areas
of 1% annual chance flood with average
depth less than one foot or with drainage
areas of less than one square mileZone X
Future Conditions 1% Annual
Chance Flood HazardZone X
Area with Reduced Flood Risk due to
Levee. See Notes.Zone X
Area with Flood Risk due to LeveeZone D
NO SCREEN Area of Minimal Flood Hazard Zone X
Area of Undetermined Flood HazardZone D
Channel, Culvert, or Storm Sewer
Levee, Dike, or Floodwall
Cross Sections with 1% Annual Chance
17.5 Water Surface Elevation
Coastal Transect
Coastal Transect Baseline
Profile Baseline
Hydrographic Feature
Base Flood Elevation Line (BFE)
Effective LOMRs
Limit of Study
Jurisdiction Boundary
Digital Data Available
No Digital Data Available
Unmapped
This map complies with FEMA's standards for the use of
digital flood maps if it is not void as described below.
The basemap shown complies with FEMA's basemap
accuracy standards
The flood hazard information is derived directly from the
authoritative NFHL web services provided by FEMA. This map
was exported on 2/3/2023 at 11:33 AM and does not
reflect changes or amendments subsequent to this date and
time. The NFHL and effective information may change or
become superseded by new data over time.
This map image is void if the one or more of the following map
elements do not appear: basemap imagery, flood zone labels,
legend, scale bar, map creation date, community identifiers,
FIRM panel number, and FIRM effective date. Map images for
unmapped and unmodernized areas cannot be used for
regulatory purposes.
Legend
OTHER AREAS OF
FLOOD HAZARD
OTHER AREAS
GENERAL
STRUCTURES
OTHER
FEATURES
MAP PANELS
8
B 20.2
The pin displayed on the map is an approximate
point selected by the user and does not represent
an authoritative property location.
1:6,000
105°3'31"W 40°35'47"N
105°2'54"W 40°35'20"N
Basemap: USGS National Map: Orthoimagery: Data refreshed October, 2020
F
APPENDIX F – D RAINAGE E XHIBIT
TEST
STA
TEST
STA
V.P.
ST
F.O.
X
X
XX
X
X
X
X
X
X
X
X
X
UD
UD
UD
UD
UDUD
UD
UD
UD
UD
UD
UD
UD
UD
UD
UD
UD
UD
UD
UD
UD
UD
UD
UD
UD
UD
UD
/ / / / / / / /
/ / / / / / / /
PROPOSED
STORM DRAIN
PROPOSED
POND OUTFALL
PROPOSED 2'
CONCRETE PAN
PROPOSED
STORM DRAIN
PROPOSED
STORM DRAIN
PROPOSED 2'
CONCRETE PAN
PROPOSED
STORM DRAIN
EXISTING
STORM DRAIN
EXISTING
STORM DRAIN
PROPOSED 2'
CONCRETE PAN
POND OUTLET
STRUCTURE
PROPOSED
CULVERT
A
2.55 ac
B
1.93 ac
D
1.58 ac
C
3.95 ac
E
3.93 ac
J
0.31 ac
K
0.45 ac
OS1
.906 ac
M
2.47 ac
L
0.64 ac
N
1.01 ac
POND OUTLET
STRUCTURE
PROPOSED
STORM DRAIN
C
D
E
B
J
K
OS1
L
M
N
A
NO
R
T
H
L
E
M
A
Y
A
V
E
N
U
E
DUFF DRIVE
LINK LANE
DETENTION
POND 2
RAIN
GARDEN A
RAIN
GARDEN D
DETENTION
POND 1
RAIN
GARDEN B
DOG PARK
RAIN
GARDEN M
OF
SCALE:
PROJECT NO.
PR
O
J
E
C
T
M
A
N
A
G
E
R
:
NO
.
RE
V
I
S
I
O
N
S
BY
:
DA
T
E
:
SU
B
M
I
T
T
A
L
D
A
T
E
:
SHEET:
HORIZ:
VERT:
CAUTION
The engineer preparing these
plans will not be responsible
for, or liable for, unauthorized
changes to or uses of these
plans. All changes must be
approved by the Professional
Engineer of these plans.
04
/
1
0
/
2
4
TH
E
L
A
N
D
I
N
G
A
T
L
E
M
A
Y
71
1791-003
D.
W
e
b
e
r
13
3
7
R
I
V
E
R
S
I
D
E
A
V
E
.
#
2
FO
R
T
C
O
L
L
I
N
S
,
C
O
8
0
5
2
4
AV
A
N
T
C
I
V
I
L
G
R
O
U
P
.
C
O
M
97
0
.
2
8
6
.
7
9
9
5
N
O
T
F
O
R
C
O
N
S
T
R
U
C
T
I
O
N
R
E
V
I
E
W
S
E
T
( IN FEET )
1 inch = ft.
Feet05050
50
100 150
PROPOSED CONTOUR
PROPOSED STORM SEWER
PROPOSED SWALE
EXISTING CONTOUR
PROPOSED CURB & GUTTER
PROPERTY BOUNDARY
PROPOSED INLET
A
DESIGN POINT
FLOW ARROW
DRAINAGE BASIN LABEL
DRAINAGE BASIN BOUNDARY
PROPOSED SWALE SECTION
11
1.REFER TO THE FINAL DRAINAGE REPORT, DATED APRIL 10, 2024 BY AVANT CIVIL
GROUP FOR ADDITIONAL INFORMATION.
2.BASINS J AND K HAVE BEEN DELINEATED AND ANALYZED FOR THE
FUTURE/ULTIMATE CONDITION OF CORDOVA ROAD.
A
FOR DRAINAGE REVIEW ONLY
NOT FOR CONSTRUCTION
LEGEND
NOTES
CALL 2 BUSINESS DAYS IN ADVANCE BEFORE YOU
DIG, GRADE, OR EXCAVATE FOR THE MARKING OF
UNDERGROUND MEMBER UTILITIES.
CALL UTILITY NOTIFICATION CENTER OF
COLORADO
Know what'sbelow.
before you dig.Call
R
DE
V
E
L
O
P
E
D
D
R
A
I
N
A
G
E
E
X
H
I
B
I
T
58
1" = 50'
N/A
C 701
POND SUMMARY TABLE
Pond ID
Tributary
Area
(Ac)1
Weighted %
Imperviousness
(%)
Extended
Detention WQCV
(cu-ft)
100-Yr.
Detention Vol.
(Ac-Ft)
100-Yr.
Detention
WSEL(Ft)
Peak
Release
(cfs)3
Pond 1 6.1 68 4716 1.27 4942.20 2.5
Pond 2 11.41 59 7713 2.76 4942.10 1
Notes:
1. Tributary area shown does not include off-site basin(s)
2. Total WQCV for site will be provded in Pond 2
3. Overall site release rate of 3.5 cfs divided between Ponds 1 and 2