HomeMy WebLinkAbout217 W. TRILBY ROAD SUBDIVISION - PDP - PDP120006 - REPORTS - DRAINAGE REPORTPRELIMINARY DRAINAGE REPORT
For: 217 West Trilby Road
Fort Collins, CO 80526
Prepared For:
AFFORDABLE ROOFING, LLC
217 West Trilby Road
Fort Collins, CO 80526
April 24, 2014
Project No. 39685.01
Prepared By:
JR Engineering, LLC
2900 South College Avenue, Suite 3D
Fort Collins, CO 80525
Page i
TABLE OF CONTENTS
Table of Contents ....................................................................................................................... i
Engineer’s Certification Block .................................................................................................... ii
General Description and Location ..............................................................................................1
Location And Existing Site Characteristics ..............................................................................1
Site Soils ..................................................................................................................................1
Storm Drainage Criteria..............................................................................................................3
Hydrologic Criteria ..................................................................................................................3
Hydraulic Criteria ....................................................................................................................3
Drainage Basins, Historic and Proposed Runoff...........................................................................5
Historic Basins .........................................................................................................................5
Developed Basins ....................................................................................................................6
Proposed Water Quality/ Detention Facilities ...........................................................................7
Stormwater Pollution Prevention .................................................................................................9
Temporary Erosion Control......................................................................................................9
Permanent Erosion Control ......................................................................................................9
Summary & Conclusions .............................................................................................................9
Existing & Proposed Conditions ..............................................................................................9
References ................................................................................................................................ 11
Appendices ............................................................................................................................... 12
Site & Soil Descriptions and Characteristics ............................................................................1
Proposed Rational & Detention Pond Calculations ...................................................................2
Existing & Proposed Condition Specific Drainage Maps ..........................................................2
A-1
A-2
A-3
Page ii
ENGINEER’S CERTIFICATION BLOCK
I hereby certify that this Preliminary Drainage Report for 217 W Trilby, Fort Collins, CO 80526
was prepared by me (or under my direct supervision) for JR Engineering, LLC and the owners
thereof and meets or exceeds the criteria of the City of Fort Collins Stormwater Design
Standards.
________________________________________
Timothy J. Halopoff, PE
Registered Professional Engineer
State of Colorado No. 37953
Page 1
GENERAL DESCRIPTION AND LOCATION
LOCATION AND EXISTING SITE CHARACTERISTICS
217 W. Trilby is located in the NORTHEAST QUARTER OF SECTION 14, TOWNSHIP 6
NORTH, RANGE 69 WEST OF THE 6TH P.M., CITY OF FORT COLLINS, COUNTY OF
LARIMER, STATE OF COLORADO. More specifically, 217 W. Trilby is a 2.485 ac. piece of
property that is currently used as a residence and a large open yard, but is zoned LMN and will
support office uses on the east & west side of the property once subdivided.
The future use of the site (2.485 ac.) entails subdividing the existing lot into 4 lots and
dedicating additional Trilby Right-of-Way (0.083 ac.). The existing residence will remain on the
new Lot 1, consisting of 0.344 ac. There will also be 3 lots created for the purpose of
constructing 3 office buildings complimented with garage spaces. Lot 2 (0.323 ac.), will be
located on the east side of the North Louden Ditch and will support a new office development
with a footprint of 3,750 s.f. The remainder of the property on the East side of the ditch will
become Lot 3 (0.520 ac.) and will support an office containing another 3,750 s.f. footprint. On
the west side of the North Louden Ditch/Drainage Swale will be Lot 4. Lot 4 consists of 1.215
ac. and will support an office structure with a garage in the back; having a foundation footprint
of 6,000 s.f.
The site generally slopes from the southwest to the northeast with slopes ranging between
2.8% and 11.0%. The property is generally covered with sparse native grasses. The North
Louden Ditch traverses the property from the southeast corner to the northwest corner,
flowing northwest and ultimately flowing into a corrugated metal pipe and crossing W. Trilby.
The westerly portion of the property (proposed Lot 4) receives a small area of off-site flow
(0.93 ac.) from the southwest and together with the on-site Lot 4 flows, accumulate a total area
of 2.28 ac., which currently drains to two points on the ditch. On the east side of the ditch,
which is where the residence is located, 0.78 ac. drains east to two existing sumps on the east
property line. Ultimately, the historic flow from the residence and the major portion of the site
east of the ditch, flow to the northeastern corner of the property and into the West Trilby
Road right-of-way. The Southeast portion of the property, easterly Lots 2 and 3 drain to the
north easterly neighboring property. The small portions of land on the extreme north of both
sides of the ditch drain to the south roadside borrow ditch on Trilby.
SITE SOILS
The 217 West Trilby site consist of loams including: Fort Collins Loam, Thedalund Loam and
Wiley Silt Loam. Fort Collins Loam (Classification #36), having 3-5% slopes, generally has a
combined surface layer thickness of approx. 20 inches. Runoff is moderate, and the hazards of
wind and water erosion are moderate. Thedalund Loam (Classification #108), having 3-9%
slopes, occasionally has a surface layer of clay loam and small areas of Kim, Cushman, and
Midway soils. Runoff is medium, and the hazard of erosion is moderate. Wiley Silt Loam
(Classification #119), having 3-5% slopes, occasionally has a subsurface layer of silt loam or
loam. Runoff is medium, and the hazard of erosion is medium.
All of the loams on this site are classified as being in the Type B hydrologic group. According
to USDA/Natural Resource Conservation Group, the earth on-site has a moderate infiltration
rate when thoroughly wet. These soils consist chiefly of moderately deep or deep, moderately
Page 2
well drained or well drained soils that have a moderately fine texture to moderately coarse
texture. These soils also have a moderate rate of soils transmission.
Supporting figures can be found in the Appendix, page A-1.
Page 3
STORM DRAINAGE CRITERIA
This preliminary report was prepared to meet or exceed the City of Fort Collins storm water
criteria. The City of Fort Collin’s Storm Drainage Design Criteria and Construction Manual
(with all current 2011 Revisions)(FCSDDCCM) and the Urban Drainage Flood Control
District’s (UDFCD) Drainage Criteria Manual (USDCM) Volumes 1, 2 and 3 were referenced as
guidelines for this design.
HYDROLOGIC CRITERIA
The rational method was performed to calculate the peak runoff rates for each basin.
Weighted percent imperviousness and weighted runoff coefficients were calculated for each
basin using USDCM Tables RO-3 and RO-5 based on Natural Resources Conservation Service
(NRCS) Type B hydrologic soil classification and surface characteristics of each basin. The time
of concentration was calculated using USDCM Equation RO-3 and the intensity was calculated
using the corresponding storm rainfall depth and USDCM Equation RA-3. To account for the
City of Fort Collins’ IDF Curve, Coefficient 3 of the UDFCD’s intensity formula was adjusted to
0.7867. The City of Fort Collins area has 2-yr 1-hr rainfall depth of 0.82 inches and a 100-yr 1-
hr rainfall depth of 2.86 inches. These depths do account for the 1997 adjusted rainfall depths.
HYDRAULIC CRITERIA
The hydraulic calculations provided for in this report are limited to Detention Pond
calculations. This report proves that the system of proposed detention ponds is able to reduce
the 100-year developed condition flows to the 2-year historical release rates; thereby satisfying
the City’s requirements. Once this Preliminary Report is accepted and approved, hydraulic
calculations for storm drain pipe, water quality structures and rip-rap will be provided within
the Final Drainage Report for 217 West Trilby.
The ultimate 217 West Trilby storm drainage system will be designed to convey the minor and
major storm events through the property with the proposed inlets, storm sewer pipes, and
swales for the flows being calculated by this preliminary report. Per the requirements provided
by the City of Fort Collins Storm Drainage Design Criteria and Construction Manual, all inlets
and storm pipes will be designed to convey the 100-year storm flows. During the major storm
event, the developed condition 100-yr storm, the accumulated water depth will be held to a
maximum depth with a minimum of 1’ freeboard to the top of all building finished floors.
Additionally, the detention ponds will be designed to detain all onsite flows and maintain 1’ of
freeboard. This report shows that there are no changes to offsite flows, but in an effort to
minimize the offsite flows passing through the site detention ponds 1 and 3 will detain a large
majority of the flows. This will help to minimize damage and potential loss of life in the event of
a storm equal to the 100-yr or greater.
Page 4
All swale and pipe outlets will be protected with turf mat or riprap; whichever the City
requires. Storm sewer pipe outlets will be protected using the requirements set by the
USDCM for the protection of downstream conveyance channels and culverts.
Page 5
DRAINAGE BASINS, HISTORIC AND PROPOSED RUNOFF
HISTORIC BASINS
217 West Trilby is an infill development piece of property. As such, the existing and proposed
drainage basins will need to follow the generally accepted principle of releasing the 100-yr
developed condition storm flow at the same location and magnitude as the 2-yr. historic
condition flow rate. There are offsite areas that flow across the proposed development site.
Referring to the “Existing Drainage Plan” (Appx. - Sht. 1 of 2, included in the sleeve at back),
the following describes the existing condition drainage basins.
Existing Offsite Drainage Basins (OF):
Sub-basin OF1 consists of 1.21 acres that flows northeasterly, across private property
and the storm drainage travels on the south curb and gutter/southerly roadside ditch of
Trilby Road. Along this path, the drainage from Sub-basin OF1 stays north of the
subject development property in the existing condition.
Sub-basin OF2 consists of 0.93 acres that flows easterly, across private property and
enters the onsite development property at the southwest corner; where the flow is
conveyed by Basin ON2 to the North Louden Ditch irrigation channel.
Sub-basin OF3 consists of 2.48 acres that flows easterly, across private property and
the storm drainage travels on the south curb and gutter/southerly roadside ditch of
Trilby Road. Along this path, the drainage from Sub-basin OF3 stays north of the
subject development property in the existing condition.
Sub-basin OF4 consists of 0.56 acres that flows northeasterly, across private property
and the drainage travels along the south side of the subject property. Along this path,
the drainage from Sub-basin OF4 stays to the south of the subject development
property and for this reason, is excluded from the hydraulic/detention pond calculations.
Existing Onsite Drainage Basins (ON):
Sub-basin ON1 consists of 0.43 acres that flows easterly, across the northwest ¼ of
the development property, conveying flow from Sub-Basin OF1 and its own flow,
making the total area flowing to the North Louden Ditch at the bottom of ON1 1.95 ac.
Sub-basin ON2 consists of 0.92 acres that flows northeasterly, across the southwest
¼ of the development property, conveying flow from Sub-Basin OF2 and its own flow,
making the total area flowing to the North Louden Ditch at the bottom of ON2 1.85 ac.
Sub-basin ON3 consists of 0.55 acres that flows easterly, across the southeast ¼ of
the development property. This Sub-basin drains to a sump area located midway of the
easterly property line and flows directly to the neighboring property, where it makes its
way back to Trilby’s south borrow ditch.
Page 6
Sub-basin ON4 consists of 0.23 acres that flows easterly, across the northeast ¼ of
the development property. This Sub-basin drains to a sump area located at the top of
the easterly property line and flows directly to the neighboring property, where it
makes its way to the south borrow ditch at Trilby.
DEVELOPED BASINS
The proposed developed condition sub-basins have been designed to mimic the historic basins,
both on and off-site. The major difference between the proposed on-site sub-basins and the
existing on-site sub-basins is that in the developed condition, all on-site flows west of the ditch,
that historically flowed into the ditch, are routed through the detention pond system and
conveyed to the northeast corner of the site. Furthermore, because we have been able to
keep the off-site sub-basins nearly the same for the existing and proposed conditions, we were
able to avoid re-calculating and reiterating the information provided for off-site in the prior
section. Referring to the “Proposed Drainage Plan” (Appx. - Sht. 2 of 2, included in the sleeve
at back), the following describes the proposed condition on-site drainage basins.
Proposed Onsite Drainage Basins (ON):
Sub-basin A1 consists of 0.07 acres and flows from the high point on the Lot 4 access
drive. From there, flows are routed north to the inlet at design point 2 found on the
east side of the Lot 4 access drive. Captured flows are piped to Detention Pond 2.
Sub-basin A2 consists of 0.12 acres and flows from the high point on the bermed area
east of the relocated North Louden Ditch and will flow directly into an area inlet in the
rear of the existing building on Lot 1. Once the flows are captured by the area inlet at
design point 3 they are piped to Detention Pond 5.
Sub-basin A3 consists of 0.32 acres including the building on Lot 4 and flows from the
back of curb where Sub-basin A1 enters the inlet at design point 2. From there, flows
are routed to the southeast where it combines with the runoff from sub-basin A1 into
Detention Pond 2. Once the storm flows reach Pond 2, they are detained using a water
quality detention structure at design point 4. Then storm water is conveyed to
Detention Pond 5, via storm pipe that passes under the newly aligned ditch and down
the easterly common drive.
Sub-basin A4 consists of 0.10 acres and flows from the high point on the Lot 2 access
drive as well as the existing building on Lot 1. From there, flows are routed north to
the inlet at design point 5 found on the east side of the Lot 2 access drive. Once the
flows are captured by the inlet they are piped to Detention Pond 5.
Sub-basin A5 consists of 0.06 acres and is made up of the area used for Detention
Pond 5. From there, flows are routed northeast to the water quality/ detention
structure at design point 6. Once the flows are detained by the structure, they are piped
to design point 10 where the flows are combined with flows from Sub-basins B1&2.
Page 7
Sub-basin B1 consists of 0.52 acres and flows from the pick-up point where Off-site
Sub-basin OF2 enters the site in the southwest. From there, flows are routed down the
back of the parking lot retaining wall in a trickle pan. The trickle pan conveys flows to
Detention Pond 3, behind the building on Lot 4. This detention pond utilizes retaining
walls and provides adequate detention prior to conveying flows through storm pipe,
under the newly aligned ditch and into Pond 4, on Lot 3.
Sub-basin B2 consists of 0.70 acres and flows from the high points on the bermed
areas east of the relocated North Louden Ditch and will flow directly into the new
native/low water tolerant grassed Detention Pond 4 located in the rear of the proposed
building on future Lot 3. Flows are routed down a trickle pan in Pond 4 and through
the water quality/detention structure. Following the water quality/detention structure,
the flows are routed down the easterly property boundary via a small concrete channel.
PROPOSED WATER QUALITY/ DETENTION FACILITIES
Water quality and detention will be provided with four on-site water quality/detention ponds
and one off-site water quality/ detention pond. The detention pond release rates were
calculated using the on-site 2-year historic flows and portions of the off-site 100-yr flows for
contributing basins. See Appendix A3 for maps showing the on-site 2-year historic flows and
off-site 100-yr historic flows. The modified Detention Pond Calculator “FAA12” (Fater, Judish &
Li; 1998) was used to calculate the required detained storm water volume, to which the volume
calculated for Water Quality, was then added. The additional storage found in Ponds 1 & 3 is
used to minimize the off-site runoff from sub-basins OF1-3 and lowers the overall release rate
of the entire site. See Table 1 below for pond sized and release rates. The weir sizes for each
pond were calculated using the 100-year storm flows from both the historic off-site and
developed on-site, which assumes that the outlet structure is completely clogged. All five
detention ponds will be fitted with water quality structures to maximize on-site storage and to
detain developed condition storm flows.
Table 1 Detention Pond Values
Detention
Pond
Storage Volume
Required (acre-ft)
Storage Volume
Provided (acre-ft)
100-yr Max Inflow
Rate (cfs)
100-yr Max
Release Rate (cfs)
1 0 0.07 10.00 7.48
2 0.04 0.04 1.77 0.27
3 0.07 0.12 4.63 1.73
4 0.07 0.07 4.29 2.37
5 0.02 0.02 1.28 0.63
Proposed Water Quality/Detention Facilities:
Pond 1 is an off-site water quality and detention pond located in the northwest corner
of the site and collects flows from off-site basins OF1 and OF3. Pond 1 was not
Page 8
required but 0.072 acre-feet is provided to detain some of the off-site flow coming
through the north portion of the site, then releasing back to the Trilby Road Borrow
Ditch.
Pond 2 is an on-site water quality and detention pond located in the northern portion
of Lot 4 and collects flows from sub-basins A1 and A3. This pond detains the 100-yr
developed on-site flows and releases 0.27 cfs in the 100-year event. Flows released
from Pond 2 are piped to Pond 5. The emergency weir overflow weir for Pond 2 flows
into the North Louden Ditch.
Pond 3 is an on-site water quality and detention pond located in the southern portion
of Lot 4 and collects flows from sub-basins B1 and OF2. This pond detains the 100-yr
developed on-site flows as well as the 100-yr historic off-site flows. Pond 3 releases
1.73 cfs in the 100-year event. Flows released from Pond 3 are piped to Pond 4. The
emergency overflow weir from Pond 3 flows into the North Louden Ditch.
Pond 4 is an on-site water quality and detention pond located in the southeastern
corner of the site on Lot 3 and collects flows from sub-basin B2 as well as flows piped
from Pond 3. This pond detains the 100-yr developed on-site flows in addition to the
flows piped from Pond 3. Pond 4 releases 2.37 cfs in the 100-year event. Flows
released from Pond 4 are routed along the easterly property boundary via a small
concrete channel to design point 10. The emergency overflow weir for Pond 4 flows
east offsite.
Pond 5 is an on-site water quality and detention pond located in the northeastern
corner of the site on Lot 2 and collects flows from sub-basins A2, A4 and A5 as well as
flows piped from Pond 2. This pond detains the 100-yr developed on-site flows in
addition to the flows piped from Pond 2. Pond 5 releases 0.63 cfs in the 100-year event.
Flows released from Pond 5 are piped to design point 10 where they combine with
flows released from Pond 4. The emergency overflow weir for Pond 5 flows north into
the right-of-way.
Page 9
STORMWATER POLLUTION PREVENTION
TEMPORARY EROSION CONTROL
A temporary erosion control plan is to be implemented for the site during construction.
Temporary erosion control measures include, but are not limited to, slope and swale
protection, silt fence placed around downstream areas of disturbance, construction vehicle
tracking pad at entrances, a designated concrete truck washout basin, designated vehicle fueling
areas, inlet protection, etc. All temporary erosion control measures are to be removed after
they are deemed unnecessary.
PERMANENT EROSION CONTROL
Permanent erosion control measures include, but are not limited to, the constructed
detention/water quality ponds, riprap pads placed for culvert outlet protection, seeding and
mulch placed to enable and established vegetative growth, etc. Long-term maintenance of these
erosion control measures shall be the responsibility of the owner of the property.
A general erosion control plan will be included with the Final Development Plan, Utility Plan set
and in the appendix of the Final Development Plan Drainage Report. Ultimately before
construction of this project, a more detailed Storm Water Management Plan (SWMP) will need
to be performed per the storm drainage criteria requirements of the City of Fort Collins.
SUMMARY & CONCLUSIONS
To summarize the flow rates and detention pond characteristics, we have shown calculations
per the City’s requirements for Preliminary Drainage reports in Appendix A-2, “Proposed
Rational and Detention Pond Calculations”. To calculate on-site release rates, we calculated
the 2-year historic on-site flows for contributing basins (1.49 cfs). The 2-year historic on-site
flows west of the ditch were then reduced by actual area developed. By combining these
reduced 2-year historic on-site flows we get the total allowable site release rate (1.23 cfs). We
then used the modified Detention Pond Calculator “FAA12” (Fater, Judish & Li; 1998) to
calculate the required detained storm water volume, to which the volume calculated for Water
Quality, was then added. A SWMM model was also created to ensure that the detention pond
volumes were fully utilized. The weir size was calculated using the 100-year storm flows from
both the historic off-site and developed on-site, which assumes that the outlet structure is
completely clogged. All five detention ponds will be fitted with water quality structures to
maximize on-site storage and to detain developed condition storm flows to a flow rate below
the allowable release rate of 14.63 cfs which includes 100-year runoff from off-site basins OF1-3
(13.40 cfs) and the 2-year historic allowable on-site runoff (1.23 cfs).
EXISTING & PROPOSED CONDITIONS
For the Existing & Proposed Condition Specific Drainage Map see Appendix A3. Sub basins
outlined in green have storm runoff that flow into the right-of-way. Sub basins outlined in red
Page 10
have storm runoff that flows into the north louden ditch. Sub basins outlined in blue have
storm runoff that flows to property east of the site.
The major differences between the existing condition and the proposed condition are as
follows:
1. In the existing conditions offsite flow was allowed to flow along Trilby Road and into the
row, now those same areas drain to Detention Pond 1 where they are reduced before
being piped to the row.
2. In the existing conditions some offsite and onsite runoff was allowed to drain into the
north louden ditch, now those same areas drain to Detention Pond 3 where the runoff
is detained. From Pond 3 the runoff is reduced and piped under the ditch to Pond 4
where the flows are detained and reduced before being released to property east of the
site.
3. In the existing condition the total runoff draining to the property east of the site was
11.54 cfs assuming 100-year storm runoff for off-site basins and historic 2-year runoff
for on-site basins. In the proposed condition the total runoff draining to the property
east of the site is 10.94 cfs which includes all additional runoff from sub basins OF2, A1,
A3, and B1. This outfall reduction was accomplished by reducing on-site and off-site
runoff during the 100-year storm. On-site runoff was reduced to 2-year historic rates by
using the detention pond system. Off-site runoff was minimized by adding Detention
Pond 1 which handles runoff from off-site basins OF1 & OF3, and oversizing Detention
Pond 3 which handles runoff from off-site basin OF2.
In conclusion, all of the City of Fort Collins hydrology calculations were performed using the
required methods and all of the 217 Trilby Project drainage amenities, meet or exceed the
necessary drainage feature requirements. Furthermore, this preliminary drainage report and
the complimenting Overall Utility Plans show appropriate grading, permanent landscaping,
riprap, and on-site construction facilities (e.g. storm pipes, inlets, etc.) that will be calculated
hydraulically and discussed in the Final Drainage Report and on it’s accompanying Maps.
Page 11
REFERENCES
1. Urban Storm Drainage Criteria Manual (Volumes 1, 2, and 3), Urban Drainage and Flood
Control District, June 2001.
2. Storm Drainage Criteria Manual and Construction Standards, City of Fort Collins Storm
Water Utility, City of Fort Collins, Colorado, Updated January, 1997.
3. “Hydrologic Group Rating for Larimer County Area, Colorado”, USDA-Natural Resources
Conservation Service, National Cooperative Soil Survey. Web Soil Survey URL:
http://websoilsurvey.nrcs.usda.gov. [July 21, 2010]
Page 12
APPENDICES
Site & Soil Descriptions and Characteristics (A-1)
Proposed Rational & Detention Pond Calculations (A-2)
Existing & Proposed Condition Specific Drainage Map (A-3)
Existing & Proposed Drainage Plans (Sleeve)
SITE & SOIL DESCRIPTIONS AND CHARACTERISTICS
PROPOSED RATIONAL & DETENTION POND CALCULATIONS
Subdivision: Affordable Roofing Project Name: Affordable Roofing
Location: User Defined Project No.:
Calculated By: Joey
Checked By: 0
Date: 3/24/14
A1 0.0666 95 0.07 95.0 5 0.00 0.0 42 0.00 0.0 95.0
A2 0.1240 95 0.00 0.0 5 0.12 5.0 42 0.00 0.0 5.0
A3 0.3164 95 0.16 48.6 5 0.15 2.4 42 0.00 0.0 51.0
A4 0.1038 95 0.10 88.7 5 0.01 0.3 42 0.00 0.0 89.0
A5 0.0590 95 0.01 16.1 5 0.05 4.2 42 0.00 0.0 20.3
B1 0.5225 95 0.30 54.9 5 0.22 2.1 42 0.00 0.0 57.0
B2 0.7027 95 0.46 61.6 5 0.25 1.8 42 0.00 0.0 63.4
OF1 1.2088 95 0.00 0.0 5 1.21 5.0 42 0.00 0.0 5.0
OF2 0.9300 95 0.00 0.0 5 0.93 5.0 42 0.00 0.0 5.0
OF3 2.1460 95 0.51 22.5 5 1.64 3.8 42 0.00 0.0 26.3
OF4 0.5200 95 0.00 0.0 5 0.52 5.0 42 0.00 0.0 5.0
OF5 0.0740 95 0.00 0.0 5 0.07 5.0 42 0.00 0.0 5.0
OF6 0.1998 95 0.10 47.6 6 0.10 3.0 42 0.00 0.0 50.6
OF7 0.0940 95 0.05 47.5 5 0.05 2.5 42 0.00 0.0 50.0
Area (ac) Weighted
% Imp.
Hardscape Landscaping
Weighted
% Imp. % Imp. Area (ac)
39685.01
COMPOSITE % IMPERVIOUS CALCULATIONS
Weighted
% Imp.
Basins Total
Weighted %
Basin ID Total Area (ac) % Imp. Area (ac) Imp.
Building
% Imp.
X:\3960000.all\3968500\Excel\Drainage\Drainage Calcs.xls Page 7 of 24 4/24/2014
Subdivision: Affordable Roofing Project Name: Affordable Roofing
Location: User Defined Project No.:
Calculated By: Joey
Checked By: 0
Date: 3/24/14
FINAL
BASIN D.A. Hydrologic Impervious C100 C2 C5 L S Ti L S Cv VEL. Tt COMP. Tc TOTAL Urbanized Tc Tc
ID (AC) Soils Group (%) (FT) (%) (MIN) (FT) (%) (FPS) (MIN) (MIN) LENGTH(FT) (MIN) (MIN)
A1 0.07 B 95.0 0.88 0.79 0.81 25 2.0 2.1 100 1.0 20.0 2.0 0.8 2.9 125.0 10.7 5.0
A2 0.12 B 5.0 0.38 0.04 0.10 50 2.0 10.3 100 2.0 7.0 1.0 1.7 12.0 150.0 10.8 10.8
A3 0.32 B 51.0 0.53 0.30 0.36 50 2.0 7.6 65 2.0 7.0 1.0 1.1 8.7 115.0 10.6 8.7
A4 0.10 B 89.0 0.80 0.69 0.71 50 2.0 4.0 70 1.0 20.0 2.0 0.6 4.6 120.0 10.7 5.0
A5 0.06 B 20.3 0.44 0.12 0.20 25 2.0 6.5 50 2.0 10.0 1.4 0.6 7.1 75.0 10.4 7.1
B1 0.52 B 57.0 0.55 0.34 0.39 50 2.0 7.3 300 1.0 20.0 2.0 2.5 9.8 350.0 11.9 9.8
B2 0.70 B 63.4 0.58 0.39 0.44 90 2.0 9.1 265 1.0 20.0 2.0 2.2 11.3 355.0 12.0 11.3
OF1 1.21 B 5.0 0.38 0.04 0.10 50 2.0 10.3 450 2.0 7.0 1.0 7.6 17.9 500.0 12.8 12.8
OF2 0.93 B 5.0 0.38 0.04 0.10 50 2.0 10.3 350 2.0 7.0 1.0 5.9 16.2 400.0 12.2 12.2
OF3 2.15 B 26.3 0.46 0.15 0.23 50 2.0 8.9 900 2.0 7.0 1.0 15.2 24.1 950.0 15.3 15.3
OF4 0.52 B 5.0 0.38 0.04 0.10 50 2.0 10.3 450 2.0 7.0 1.0 7.6 17.9 500.0 12.8 12.8
OF5 0.07 B 5.0 0.38 0.04 0.10 50 2.0 10.3 265 2.0 7.0 1.0 4.5 14.7 315.0 11.8 11.8
OF6 0.20 B 50.6 0.53 0.30 0.35 20 2.0 4.9 195 2.0 7.0 1.0 3.3 8.2 215.0 11.2 8.2
OF7 0.09 B 50.0 0.52 0.29 0.35 20 2.0 4.9 120 2.0 7.0 1.0 2.0 6.9 140.0 10.8 6.9
OF8 0.34 B 5.0 0.38 0.04 0.10 50 20.0 4.8 320 1.5 15.0 1.8 2.9 7.7 370.0 12.1 7.7
NOTES:
Ti = (0.395*(1.1 - C5)*(L)^0.5)/((S)^0.33), S in ft/ft
Tt=L/60V (Velocity From Fig. 501)
Velocity V=Cv*S^0.5, S in ft/ft
Tc Check = 10+L/180
For Urbanized basins a minimum Tc of 5.0 minutes is required.
For non-urbanized basins a minimum Tc of 10.0 minutes is required
STANDARD FORM SF-2
TIME OF CONCENTRATION
SUB-BASIN Tc CHECK
39685.01
DATA (URBANIZED BASINS)
INITIAL/OVERLAND
(Ti)
TRAVEL TIME
(Tt)
X:\3960000.all\3968500\Excel\Drainage\Drainage Calcs.xls Page 8 of 24 4/24/2014
Project Name: Affordable Roofing
Subdivision: Affordable Roofing Project No.:
Location: User Defined Calculated By: Joey
Design Storm: Checked By: 0
Date:
TRAVEL TIME
STREET
Design Point
Basin ID
Area (Ac)
Runoff Coeff.
Tc (min)
C*A (Ac)
I (in/hr)
Q (cfs)
Tc (min)
C*A (Ac)
I (in/hr)
Q (cfs)
Slope (%)
Street Flow (cfs)
Design Flow (cfs)
Slope (%)
Pipe Size (inches)
Length (ft)
Velocity (fps)
Tt (min)
REMARKS
OF1 1.21 0.04 12.78 0.05 2.00 0.1
OF3 2.15 0.15 15.28 0.32 1.85 0.6
Combines OF1 & OF3 in basin OF1 Detention Pond 1
1 15.28 0.37 1.85 0.7 0.7 1.00 17 90 3.3 0.5 Captured by Sump and Piped to DP 9
2 A1 0.07 0.79 5.00 0.05 2.78 0.1 0.1 1.00 12 115 2.1 0.9 Captured by Sump and Piped to DP 4
3 A2 0.12 0.04 10.83 0.01 2.15 0.0 0.0 0.50 12 70 0.7 1.6 Captured by Sump and Piped to DP 5
A3 0.32 0.30 8.70 0.09 2.34 0.2
combines A1 with Basin A3 in Detention Pond 2
4 8.70 0.14 2.34 0.3 0.3 0.50 12 196 2.1 1.5 Captured by Sump and Piped to DP 5
A4 0.10 0.69 5.00 0.07 2.78 0.2
Combines pipe flows from DP 3 & 4 w/ basin A4
5 10.23 0.22 2.20 0.5 0.5 0.5 12 30 2.4 0.2 Captured by Sump and Piped to basin A5 Detention Pond 5
A5 0.06 0.12 7.13 0.01 2.51 0.0
Combines basin A5 w/ Pipe flows from DP5
6 10.44 0.23 2.18 0.5 0.5 0.50 12 33 2.5 0.2 Captured by Sump and Piped to DP 10
OF2 0.93 0.04 12.22 0.04 2.04 0.1
B1 0.52 0.34 9.80 0.18 2.24 0.4
Combines B1 & OF2 in basin B1 Detention Pond 3
7 12.22 0.22 2.04 0.4 0.4 0.50 12 90 2.4 0.6 Captured by Sump and Piped to DP 8
B2 0.70 0.39 11.31 0.27 2.11 0.6
Combines Basin B2 w/ pipe flows from DP7
8 12.86 0.49 2.00 1.0 1.0 0.50 19 275 2.8 1.6 Captured by Sump and Piped to DP 10
OF6 0.20 0.30 8.16 0.06 2.39 0.1
combines flows from Dp1 with Basin OF6
9 15.74 0.43 1.82 0.8 0.8 1.00 17 50 3.4 0.2 Captured by Sump and Piped to DP 10
OF7 0.09 0.29 6.89 0.03 2.53 0.1
10 16.0 1.18 1.81 2.1 Total
DIRECT RUNOFF TOTAL RUNOFF STREET PIPE
3/24/14
STANDARD FORM SF-3
STORM DRAINAGE SYSTEM DESIGN
(RATIONAL METHOD PROCEDURE)
STANDARD FORM SF-3
STORM DRAINAGE SYSTEM DESIGN
(RATIONAL METHOD PROCEDURE)
Project Name: Affordable Roofing
Subdivision: Affordable Roofing Project No.:
Location: User Defined Calculated By: Joey
Design Storm: Checked By: 0
Date: 3/24/14
TRAVEL TIME
STREET
Design Point
Basin ID
Area (Ac)
Runoff Coeff.
Tc (min)
C*A (Ac)
I (in/hr)
Q (cfs)
Tc (min)
C*A (Ac)
I (in/hr)
Q (cfs)
Slope (%)
Street Flow (cfs)
Design Flow (cfs)
Slope (%)
Pipe Size (inches)
Length (ft)
Velocity (fps)
Tt (min)
REMARKS
OF1 1.21 0.38 12.78 0.46 6.99 3.2
OF3 2.15 0.46 15.28 0.99 6.44 6.4
Combines OF1 & OF3 in basin OF1 Detention Pond 1
1 15.28 1.45 6.44 9.3 9.3 0.50 17 90 5.9 0.3 Captured by Sump and Piped to DP 9
2 A1 0.07 0.88 5.00 0.06 9.70 0.6 0.6 2.00 12 115 4.3 0.4 Captured by Sump and Piped to DP 4
3 A2 0.12 0.38 10.83 0.05 7.49 0.4 0.4 0.50 12 70 2.2 0.5 Captured by Sump and Piped to DP 5
A3 0.32 0.53 8.70 0.17 8.16 1.4
combines A1 with Basin A3 in Detention Pond 2
4 8.70 0.23 8.16 1.9 1.9 0.50 12 196 3.5 0.9 Captured by Sump and Piped to DP 5
A4 0.10 0.80 5.00 0.08 9.70 0.8
Combines pipe flows from DP 3 & 4 w/ basin A4
5 9.64 0.36 7.85 2.8 2.8 0.5 12 30 3.6 0.1 Captured by Sump and Piped to basin A5 Detention Pond 5
A5 0.06 0.44 7.13 0.03 8.74 0.3
Combines basin A5 w/ Pipe flows from DP5
6 9.78 0.39 7.81 3.0 3.0 0.50 12 33 3.9 0.1 Captured by Sump and Piped to DP 10
OF2 0.93 0.38 12.22 0.35 7.12 2.5
B1 0.52 0.55 9.80 0.29 7.80 2.3
Combines B1 & OF2 in basin B1 Detention Pond 3
7 12.22 0.64 7.12 4.6 4.6 0.50 12 90 5.8 0.3 Captured by Sump and Piped to DP 8
B2 0.70 0.58 11.31 0.41 7.36 3.0
Combines Basin B2 w/ pipe flows from DP7
8 12.48 1.05 7.06 7.4 7.4 0.50 19 275 4.9 0.9 Captured by Sump and Piped to DP 10
OF6 0.20 0.53 8.16 0.11 8.35 0.9
combines flows from Dp1 with Basin OF6
9 15.53 1.56 6.39 10.0 10.0 1.00 17 50 6.3 0.1 Captured by Sump and Piped to DP 10
OF7 0.09 0.52 6.89 0.05 8.83 0.4
10 15.7 3.05 6.36 19.4 Total
39685.01
PIPE
STANDARD FORM SF-3
STORM DRAINAGE SYSTEM DESIGN
(RATIONAL METHOD PROCEDURE)
Project Name: Affordable Roofing
Subdivision: Affordable Roofing Project No.:
Location: User Defined Calculated By: Joey
Design Storm: Checked By: 0
Date: 3/24/14
TRAVEL TIME
STREET
Design Point
Basin ID
Area (Ac)
Runoff Coeff.
Tc (min)
C*A (Ac)
I (in/hr)
Q (cfs)
Tc (min)
C*A (Ac)
I (in/hr)
Q (cfs)
Slope (%)
Street Flow (cfs)
Design Flow (cfs)
Slope (%)
Pipe Size (inches)
Length (ft)
Velocity (fps)
Tt (min)
REMARKS
39685.01
PIPE
100-Year
DIRECT RUNOFF TOTAL RUNOFF STREET
A1 0.07 0.88 5.00 0.06 9.70 0.6
A2 0.12 0.38 10.83 0.05 7.49 0.4
A3 0.32 0.53 8.70 0.17 8.16 1.4
A4 0.10 0.80 5.00 0.08 9.70 0.8
A5 0.06 0.44 7.13 0.03 8.74 0.3
B1 0.52 0.55 9.80 0.29 7.80 2.3
B2 0.70 0.58 11.31 0.41 7.36 3.0
OF1 1.21 0.38 12.78 0.46 6.99 3.2
OF2 0.93 0.38 12.22 0.35 7.12 2.5
OF3 2.15 0.46 15.28 0.99 6.44 6.4
OF4 0.52 0.38 12.78 0.20 6.99 1.4
OF5 0.07 0.38 11.75 0.03 7.24 0.2
OF6 0.20 0.53 8.16 0.11 8.35 0.9
OF7 0.09 0.52 6.89 0.05 8.83 0.4
OF8 0.34 0.38 7.68 0.13 8.53 1.1
X:\3960000.all\3968500\Excel\Drainage\Drainage Calcs.xls Page 11 of 24 4/24/2014
a
3
4
2 5
B
1
6
Pond3Outlet
Pond4Outlet
Pond2Outlet
Pond5Outlet
Pond1Outlet
8
3
4
2 5
9
1
6
OutfallB
Pond3
Pond4
Pond2 Pond5
Pond1
01/01/2005 00:05:00
Affordable Roofing Subdivision Drainage System (04/24/2014)
SWMM 5
Node Inflow Summary
Maximum Maximum Lateral Total Flow
Lateral Total Day of Hour of Inflow Inflow Balance
Inflow Inflow Maximum Maximum Volume Volume Error
Node Type CFS CFS Inflow Inflow 10^6 gal 10^6 gal Percent
1 JUNCTION 10.00 10.00 0 00:35 0.176 0.176 0.000
2 JUNCTION 1.77 1.77 0 00:30 0.0209 0.0209 0.000
3 JUNCTION 4.63 4.63 0 00:35 0.0857 0.0857 0.000
4 JUNCTION 3.02 3.02 0 00:35 0.0455 0.0455 0.000
5 JUNCTION 1.07 1.07 0 00:35 0.0167 0.0167 0.000
6 JUNCTION 1.49 1.49 0 00:30 0.0176 0.0176 0.000
8 JUNCTION 0.00 1.73 0 01:13 0 0.0857 0.000
9 JUNCTION 0.00 0.27 0 01:09 0 0.0209 0.000
OutfallB OUTFALL 0.00 10.94 0 00:48 0 0.362 0.000
Pond1 STORAGE 0.00 10.00 0 00:35 0 0.176 0.203
Pond2 STORAGE 0.00 1.77 0 00:30 0 0.0209 0.031
Pond3 STORAGE 0.00 4.63 0 00:35 0 0.0857 0.024
Pond4 STORAGE 0.00 4.29 0 00:35 0 0.131 0.073
Pond5 STORAGE 0.00 1.28 0 00:35 0 0.0376 0.234
Affordable Roofing Subdivision Drainage System (04/24/2014)
SWMM 5
Node Pond1 Total Inflow (CFS) Node Pond2 Total Inflow (CFS) Node Pond3 Total Inflow (CFS) Node Pond4 Total Inflow (CFS) Node Pond5 Total Inflow (CFS)
Elapsed Time (hours)
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 2.9 3 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 4 4.1
Total Inflow (CFS)
10.0
9.8
9.6
9.4
9.2
9.0
8.8
8.6
8.4
8.2
8.0
7.8
7.6
7.4
7.2
7.0
6.8
6.6
6.4
6.2
6.0
5.8
5.6
5.4
5.2
5.0
4.8
4.6
4.4
4.2
4.0
3.8
3.6
3.4
3.2
3.0
2.8
2.6
2.4
2.2
2.0
1.8
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0.0
Affordable Roofing Subdivision Drainage System (04/24/2014)
SWMM 5
Storage Volume Summary
Average Average Evap Infil Maximum Maximum Day of Hour of
Storage Volume Percent Percent Percent Volume Percent Maximum Maximum
Unit 1000 ft3 Full Loss Loss 1000 ft3 Full Volume Volume
Pond1 0.410 13 0 0 3.064 99 0 00:50
Pond2 0.821 45 0 0 1.818 99 0 01:08
Pond3 1.558 30 0 0 5.071 99 0 01:12
Pond4 1.118 35 0 0 3.176 99 0 01:09
Pond5 0.331 31 0 0 1.059 99 0 01:06
Affordable Roofing Subdivision Drainage System (04/24/2014)
SWMM 5
Storage Volume Summary
Maximum
Storage Outflow
Unit CFS
Pond1 7.48
Pond2 0.27
Pond3 1.73
Pond4 2.37
Pond5 0.63
Affordable Roofing Subdivision Drainage System (04/24/2014)
SWMM 5
Node Pond1 Volume (ft3) Node Pond2 Volume (ft3) Node Pond3 Volume (ft3) Node Pond4 Volume (ft3) Node Pond5 Volume (ft3)
Elapsed Time (hours)
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 2.9 3 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 4 4.1
Volume (ft3)
5100.0
5000.0
4900.0
4800.0
4700.0
4600.0
4500.0
4400.0
4300.0
4200.0
4100.0
4000.0
3900.0
3800.0
3700.0
3600.0
3500.0
3400.0
3300.0
3200.0
3100.0
3000.0
2900.0
2800.0
2700.0
2600.0
2500.0
2400.0
2300.0
2200.0
2100.0
2000.0
1900.0
1800.0
1700.0
1600.0
1500.0
1400.0
1300.0
1200.0
1100.0
1000.0
900.0
800.0
700.0
600.0
500.0
400.0
300.0
200.0
100.0
0.0
Affordable Roofing Subdivision Drainage System (04/24/2014)
SWMM 5
EXISTING & PROPOSED CONDITION SPECIFIC DRAINAGE MAPS
100-Year
DIRECT RUNOFF TOTAL RUNOFF STREET
X:\3960000.all\3968500\Excel\Drainage\Drainage Calcs.xls Page 10 of 24 4/24/2014
2-Year
39685.01
X:\3960000.all\3968500\Excel\Drainage\Drainage Calcs.xls Page 9 of 24 4/24/2014