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City of Ft. Collins pprov d Plansroved By
Approved By pp
Date
FINAL DRAINAGE REPORT,
STORMWA TER MANAGEMENT PLAN
AND
EROSION CONTROL PLAN
Discovery Fellowship Church
Facilities Expansion
6630 Brittany Drive,
Fort Collins, Colorado
Prepared For:
Discovery Fellowship Church
6630 Brittany Drive
Fort Collins, CO 80525
970-204-6787
Prepared By:
® OWEN
CONSULTING
GROUP, INC.
3715 Shallow Pond Drive,
Fort Collins, CO 80528
Phone:970-226-0264
Fax:970-226-3760
Revised August 2013
Revised May 2013
November2012
Proj. No.: 12-389
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DISCOVERY FELLOWSHIP CHURCH
FACILITIES EXPANSION
'
FINAL DRAINAGE REPORT
Table of Contents
'
ENGINEER'S CERTIFICATION.............................................................................................
1
'
1. LOCATION AND DESCRIPTION OF PROPERTY AND PROPOSED DEVELOPMENT ......
2
A. Location............................................................................................................................
2
B. Description of Property.....................................................................................................
2
'
C. Proposed Development....................................................................................................
3
II. DRAINAGE BASINS AND SUB-BASINS................................................................................
3
A. Major Basin Description....................................................................................................
3
'
B. Sub -Basin Description......................................................................................................
3
'
III. DRAINAGE DESIGN CRITERIA.............................................................................................
A. Regulations
4
.......................................................................................................................4
B. Hydrologic Criteria............................................................................................................
4
C. Hydraulic Criteria..............................................................................................................
D. Waiver / Variance from Criteria.........................................................................................
5
5
E. Stormwater Quality Considerations..................................................................................
5
'
IV. WETLAND PRESERVATION AND MITIGATION...................................................................
6
V. DRAINAGE FACILITY DESIGN..............................................................................................
6
' A. General Concept............................................................................................................... 6
B. Specific Details....................................................................................................:............ 7
VI. CONCLUSIONS......................................................................................................................9
'
A. Compliance with Standards.............................................................................................. 9
B. Drainage Concept............................................................................................................. 9
'
VII. REFERENCES....................................................................................................................... 9
VIII. ATTACHMENTS
'
IX. DRAWINGS
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DISCOVERY FELLOWSHIP CHURCH
FACILITIES EXPANSION
FINAL DRAINAGE REPORT
ENGINEER'S CERTIFICATION
I hereby attest that this report of the Final Drainage Design for the Discovery Fellowship Church
proposed building expansion was prepared by me, or under my direct supervision, in
accordance with the provisions of the City of Fort Collins Stormwater Criteria Manual for the
responsible parties thereof. I understand that the City of Fort Collins does not and shall not
assume liability for drainage facilities designed by others.
1
Registered Professional Engineer
State of Colorado No. 29871
CG CONS
ULTING
CONSULTING
GROUP, INC.
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DISCOVERY FELLOWSHIP CHURCH
t FACILITIES EXPANSION
FINAL DRAINAGE REPORT
I. LOCATION AND DESCRIPTION OF PROPERTY AND PROPOSED DEVELOPMENT
' A. LOCATION
The church property is located at the southeast corner of the intersection of Trilby Road and
Brittany Drive, one block west of Lemay Avenue, in south Fort Collins, Colorado. The site
comprises all of the Redeemer Lutheran PUD, and is a part of the Southwest Quarter of the
' Northeast Quarter of Section 13, Township 6 North, Range 69 West of the a Principal
Meridian, City of Fort Collins, County of Larimer, State of Colorado. The site is bounded on
the west by Brittany Dr. and residential development; on the north by Trilby Rd. another
' church property; on the east by a multi -family residential development; and on the south by
single-family residential development.
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The site comprises a total area of 5.00 acres, and is developed as a church, with associated
' access driveway, parking, and landscaped open space. There is also a trailer on the site,
adjacent to the church building, which has been used as a meeting room for the churches
youth activities. In addition to the church property, there is also a small area of the adjacent
' residential development to the south that drains onto the site. This adjacent tributary area
comprises approximately 0.61 acres.
The native soils underlying the site are Renohill clay loam (77%) in the western and northern
regions and Kim loam (23%) along the eastern and perimeter of the site. The extent and
distribution of the underlying soils are shown in the attachments to this report. The Renohill
clay loam is considered to fall within NRCS Hydrologic Soil Group C, and the Kim loam falls
' within NRCS Hydrologic Soil Group B. For purposes of the drainage analysis presented in
this report, both soils are considered to be in Soil Group C, which yields a conservative
analysis.
' The existing surface of the developed site slopes from southwest to northeast. The average
surface slope is approximately 6.3%, with some areas adjacent to the existing building
' having steeper slopes of approximately 4:1, and other portions of the landscaped areas of
the site having slopes in the range of 8:1 or 9:1. Expansion plans for the church will not
change the overall grading of the site. Localized slopes adjacent to the building will be
' similar to those currently existing, with those on the north end being shifted further north to
accommodate the expanded building.
Surface runoff from the western portion of the site currently migrates across the turf areas
' and site pavement, via overland sheet flow and concentrated shallow gutter flow, and into
an inlet near the southwest comer of the church building. From there, it is conveyed via
piped storm drains to the northeast corner of the site and beneath the driveway to the
adjacent multi -family housing complex, to an open channel that carries the storm flow to a
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detention basin at the northeast corner of the multi -family site. Runoff from the north, east
and south regions of the site, as well as from the adjacent, off -site residential tributary area,
all of which is essentially landscaped area, migrates via overland sheet flow to shallow
landscaped swales along the north and east perimeters of the property, which flow to a
catchment area at the northeast corner of the property, and then via an RCP culvert,
beneath the driveway to the adjacent multi -family complex and into the open channel to the
detention area mentioned above.
An inspection of the City of Fort Collins mapping for this area indicates that the site is not
within any mapped floodplain.
C. PROPOSED DEVELOPMENT
The proposed development at the site includes the expansion of the existing building to
provide a new youth wing, to replace the existing trailer, and an expanded sanctuary to
accommodate a growing church membership. Both expansions will consist of two-story
additions to the existing building, with the youth wing having a footprint area of
approximately 4,500 s.f. and the sanctuary expansion having a footprint area of
approximately 3,200 s.f. The current youth trailer, with a footprint area of approximately 840
s.f., will be removed, once the youth wing is complete. The layout of the proposed building
expansion is shown on the Grading and Drainage Plan included as an attachment to this
Final Drainage Report.
Stormwater runoff from the within the church property, as well as from the adjacent, offsite
tributary area, will continue to flow along the current drainage pathways, with the exception
that runoff from the property and the off -site tributary area will now be captured in an on -site
detention basin, located in the northeast comer of the site, prior to being released, at a
controlled rate, to the downstream open channel.
Further discussion of the proposed stormwater management improvements is presented in
subsequent sections of this report, and appropriate graphic details are presented in the
project drawings.
' 11. DRAINAGE BASINS AND SUB -BASINS
A. MAJOR BASIN DESCRIPTION
The tributary area associated with this project comprises a total area of approximately 5.61
acres, of which approximately 1.25 acres will be disturbed during the course of constructing
the building expansion and the on -site grading and drainage improvements. The site is
located within the Fossil Creek Drainage Basin, as delineated in the City of Fort Collins
Drainage Basin Master Plan. The site is well removed, however, from the delineated flood
plain, and no specific drainage improvements from the Master Plan are applicable to this
' site, other than provision of on -site detention in accordance with the requirements of the
Stormwater Criteria Manual.
' B. SUB -BASIN DESCRIPTION
Storm runoff from the property will follow the established overland flow patterns of the
' existing development on the site. Final grading in the vicinity of the proposed building
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' expansion will cause runoff to flow away from the buildings and across the landscaped
areas to a new, on -site detention basin in the northeast comer of the site.
' In addition to the on -site tributary area, there is a small area of the adjacent residential
property to the south that will also drain onto the property and be tributary to the on -site
' detention basin. The aggregate of on -site and off -site tributary areas is 5.61 ac. For
purposes of this drainage / detention analysis, the entire site, as well as the off -site tributary
area, is considered to be a single drainage basin.
' The overall intent of the drainage design is to maximize the on -site management of
stormwater runoff emanating from the development. A small portion of the site, along the
extreme east perimeter of the property and comprising approximately 0.035 ac., is beyond
' the ridge of the perimeter swale and runoff from this area cannot practicably be captured
and directed to the on -site detention basin. Runoff from this area will flow off -site
undetained, as it currently does. This undetained flow will, however, be compensated for in
the design of the detention basin and outlet controls, such that the net effect will be as if all
of the runoff from the entire site, as well as from the off -site tributary area, is being captured
and detained.
' This property was the subject of a Final Drainage & Erosion Control Report, at the time that
the property was originally developed and the church constructed (Parsons & Associates,
' May 1992). At that time, an allowable discharge rate for the property was determined to be
7.62 cfs. The proposed project constitutes a further development of the currently developed
site, with a similar, but expanded use. The nature of both the development and runoff from
' the site will not change as a result of the proposed building expansion.
Discharge from the detention basin will be regulated via the Outlet Control Structure and
' discharged via existing piping beneath the driveway to the adjacent multi -family residential
complex and into the open channel leading eventually to Fossil Creek.
All work will be conducted in a manner designed to avoid or minimize any disruption to the
existing improvements on adjacent private properties or within the public right-of-way.
III. DRAINAGE DESIGN CRITERIA
A. REGULATIONS
' The proposed stormwater management improvements for the Discovery Fellowship Church
expansion are designed in compliance with the requirements of the City of Fort Collins
' Stormwater Criteria Manual (Stormwater Utility, Dec. 2011).
B. HYDROLOGIC CRITERIA
' As specified in the Criteria Manual, stormwater runoff from the church site is analyzed for
storms with 2-year and 100-year return frequencies.
' Due to the relatively small area of the site and the absence of any significant tributary off -
site drainage sub -basins, the Rational Method is used in the design of the system. The
Rational Method provides that:
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Q = CIA, where:
' Q = Design flow in cubic feet per second (cfs)
C = Coefficient of runoff for the area under consideration
1 = Rainfall intensity for the design storm duration (in/hr)
A = Area of the drainage sub -basin under consideration (ac)
' For purposes of this Final Drainage Report, the entire tributary area (both on -site an off -site)
is considered to be a single drainage basin. A composite runoff coefficient and percent
imperviousness are calculated for the site, based on the areas of the respective component
' surfaces (roof, pavement, landscaped areas, etc.) within the basin. Rainfall intensities are
determined using information presented in the Intensity -Duration -Frequency data in the
Criteria Manual.
' C. HYDRAULIC CRITERIA
' Within the project site, runoff will be conveyed primarily on the surface, initially as sheet flow
and subsequently as concentrated flow in shallow pans, gutters or landscaped swales.
Runoff from the southwest portion of the site, and a portion of the off -site residential area, is
collected in an inlet near the southwest comer of the church building, and piped to the
detention basin.
All accumulated flows will be intercepted and diverted into the proposed detention basin.
' Since expansion of the church building will not result in alteration of the runoff quantities or
patterns in the area served by the existing inlet and drain piping, no new stormwater
management infrastructure is required in that area, and the sizing of the existing
' infrastructure was not reviewed as part of the analysis covered by this Final Drainage
Report. Sizing of piping downstream of the proposed detention basin is addressed in this
report.
' As stated earlier, the Parsons & Associates Final Drainage Report established an allowable
release rate from the property of 7.62 cfs. That allowable release rate has been preserved
' as the basis for sizing the proposed detention basin and associated outlet control structure
for the church property. Current rainfall and runoff criteria, as set out in the Criteria Manual,
are applied in the determination of design runoff due to the prescribed storm events.
' D. WAIVER / VARIANCE FROM CRITERIA
No waivers or variances are requested in connection with the stormwater management
' design for this project.
E. STORM WATER QUALITY CONSIDERATIONS
' Permanent water quality enhancement will be provided through the design of the on -site
detention facility and, in particular, the outlet control structure within that facility. All storm
' runoff from the site and the adjacent tributary area will be directed to the on -site detention
facility. The detention facility is sized to provide capacity not only to attenuate storm flows,
but also to detain the initial runoff flows, those typically carrying the first flush of sediments
' and other possible debris from the active areas of the site, for an extended period of time, to
allow adequate time for solids to settle out in the detention basin, rather than being carried
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' into the downstream drainage improvements and receiving waters. The floor of the
detention basin will also be grassed, to provide for further fines removal and possibly some
t mitigation of chemical constituents in stormwater. Details of the detention basin design are
addressed in subsequent sections of this Final Drainage Report.
' In addition to the permanent water quality enhancement features of the stormwater system
design, provision will also be made to enhance storm water quality and erosion control
during construction. This will be accomplished through the application of Best Management
Practices (BMPs), as recommended in Volume III of the Urban Storm Drainage Criteria
Manual (UDFCD, November, 2010).
Throughout the course of construction and until such time as permanent drainage surfaces
' and/or vegetation are re-established throughout the site, appropriate measures will be
implemented and maintained to minimize erosion and limit the transport and migration of
sediment. Silt fencing will be installed along the downstream perimeter of the site (north and
' east) and, as appropriate, around sub -sites or work areas within the site, on an interim
basis. The permanent detention basin, which will have capacity to detain runoff flows from
the fully -developed site resulting from the 100-year storm event, will be constructed at the
' outset of the project, to serve as a collection point for construction stormwater, and an
interim straw -bale sediment trap will be established therein. All runoff from the disturbed
portions of the site will be directed to the detention basin, and discharge from the basin will
' be controlled. Material that accumulates in the interim sediment trap will be removed
periodically, as necessary, and properly disposed of.
' Temporary drainage swales will be established throughout the site, as necessary and
appropriate, to collect and direct storm runoff, and temporary sediment traps (hay bales,
wattle barriers, etc.) will be installed at appropriate locations to slow the runoff flows and
promote deposition of sediment and other suspended solids. Details of erosion control Best
' Management Practices (BMP's) are shown on the Erosion Control Plan, enclosed with this
report.
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Permanent landscaping will be installed within the developed areas, as soon as practicable
and temporary revegetation or mulching will be implemented if areas disturbed by
construction activities are not scheduled for immediate implementation of development
improvements and final landscaping.
IV. WETLAND PRESERVATION AND MITIGATION
There are no wetland areas within the church site.
V. DRAINAGE FACILITY DESIGN
A. GENERAL CONCEPT
The design of the drainage system for the Discovery Fellowship Church site is based on the
premise that the runoff generated within the site should be managed within the site, to the
greatest extent practicable, such that there are no adverse impacts to either the
development or adjacent or downstream properties or to downstream drainage facilities and
waterways. The grading plan for the site has been designed to promote positive drainage
away from the building, and direction of collectable runoff flow to the on -site detention basin.
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Within the bounds of the site, the proposed drainage patterns will continue to follow the
historic patterns of the predevelopment and currently developed site, with minor, localized
exceptions to encourage flow away from the building and to the permanent detention basin.
Runoff from the site will be captured and conveyed to the detention basin, located at the
northeast corner of the site. This facility will receive and attenuate runoff flows and provide
water quality enhancement. Discharge of attenuated storm water from the developed site
will be at a controlled rate, and at a location consistent with the historic experience.
The design worksheet included in the attachments to this report presents details of the
hydrologic and hydraulic calculations pertinent to the design of the storm drainage system.
A Site Grading & Drainage Improvements plan, showing the proposed site grading and the
resultant developed drainage patterns, is included in the map pocket following the
attachments.
While the primary function of the detention facility will be the attenuation of storm flows and
improvement of storm water quality prior to discharge from the site, the area will be graded
and landscaped such that it also serves as an attractive component of the site open space.
No secondary use of the detention basin will be allowed to impede or impair the primary
functions of storm water attenuation and water quality enhancement.
B. SPECIFIC DETAILS
Following is a summary of the calculated storm rainfall and runoff for the developed church
site and adjacent tributary area. The on -site detention basin is sized to accommodate runoff
from the entire area (both on -site and off -site), including the small area that is not practicably
collectable to the detention basin.
SUMMARY RUNOFF TABLE
Trib. Site Area
ac
Composite Runoff Coefficient
Design Storm Runoff
cfs
C2
Cioo
Q2
Qioo
5.61
0.40
0.50
4.24
19.39
Determination of the required capacity of the detention basin is based upon the Rational
Formula Method for small watersheds, as set out in the Criteria Manual. The Design
Worksheet and the Detention Basin Volume Calculation Worksheet included in the
attachments to this Final Drainage Report present the calculations of required and provided
detention capacities, along with the water surface elevations for the respective detention
volumes.
The allowable release rate from the detention basin was determined as part of the analysis
' developed in the Parsons & Associates report. That calculated rate of release is 7.62 eft.
The detention basin has been sized to provide storage capacity for attenuation of runoff due
' to the 100-yr storm event. The Water Quality Capture Volume (WQCV) provided within the
facility is in addition to the 100-yr storm attenuation volume. Further, the perimeter berms
forming the detention basin are designed to provide a freeboard allowance of a minimum of
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1.0 foot above the calculated water surface elevation that would be experienced during the
100-yr storm event.
The detention basin will be created by excavating the area in the northeast corner of the
site, and constructing retaining berms along portions of the perimeter of the site, to create a
closed detention area with sloping grassed walls and floor. The downstream invert of the
detention basin will be at an elevation compatible with the existing piping to be adapted to
accept discharge from the basin. Discharge piping will extend from the outlet control
structure, within the detention basin, to a connection with the existing manhole, from where
existing piping will carry the released flow beneath the access driveway to the multi -family
complex and into the open channel that currently conveys runoff further downstream.
Cobble trickle channels will be constructed within the detention basin at the toes of the
perimeter berm slopes, to convey low flows to the outlet control structure at the downstream
end of the basin. Orifice plates within the outlet control structure will regulate the rate of
release of accumulated runoff from the detention basin.
The total available active capacity of the detention basin is calculated to be 0.319 ac-ft, at
the overflow elevation of 4928.75 ft. This is equal to the aggregate volume required to
accommodate the WQCV (0.086 ac-ft) plus the100-yr stormwater attenuation (0.233 ac-ft).
Control of outflow from the detention basin will be via a reinforced concrete outlet control
structure at the downstream end of the basin, set into the interior slope of the east perimeter
impoundment berm. The outlet control structure will include two orifice plates; one mounted
on the upstream wall to regulate the release of the WQCV, and the other mounted on the
downstream wall to regulate release of the attenuated 100-yr storm runoff.
The invert of the impoundment will be at elevation 4924.15. The required WQCV will be
provided at a water surface elevation (WSE) of 4926.20 feet (2.05 ft water depth), and the
required volume for attenuation of the 100-yr storm event will be provided at a WSE of
4928.75 feet (2.55 ft incremental water depth).
Flows in excess of the 100-yr storm event will be passed through the detention basin and
will overflow, via an emergency spillway in the north impoundment berm, onto Trilby Road.
The design rate of overflow for the spillway is the 19.39 cfs, which is the peak inflow rate to
the detention basin due to the 100-yr storm event. Weir analysis indicates that a crest
length of 15 ft will pass the design flow rate, with a surcharge head of 0.52 ft, leaving a
freeboard height of 0.73 ft to the crest of the perimeter impoundment berms. The flow
velocity over the emergency spillway is calculated to be 2.44 ft/sec, which is not expected to
result in any erosion of the adjacent downstream grassed surface.
The Design Worksheet included in the attachments to this Final Drainage Report presents
hydrologic calculations for the on -site storm drainage system. Details of the detention basin
and the outlet control box are shown in the project drawings included with this Final
Drainage Report.
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VI. CONCLUSIONS
' A. COMPLIANCE WITH STANDARDS
The design for the storm water management improvements to serve the expansion of
' Discovery Fellowship Church is in compliance with the City of Fort Collins Stor mwater
Criteria Manual. The criteria and recommendations of the Urban Storm Drainage Criteria
Manual are also reflected in the design of the drainage systems.
' B. DRAINAGE CONCEPT
The drainage improvements proposed in conjunction with the expansion of Discovery
Fellowship Church, including the detention basin and outlet control works, will effectively
protect the church site, as well as downstream properties, from storm runoff, resulting in no
adverse impacts from the improvements proposed for this site. Development of the site, as
' proposed, should have a beneficial impact on water quality in downstream drainage facilities
and drainage ways due to the inclusion of storm attenuation and water quality enhancement
features in the on -site detention facility.
VII. REFERENCES
' "City of Fort Collins Stormwater Criteria Manual" (Stormwater Utility, December 2011).
"Urban Storm Drainage Criteria Manual Volumes 1 & 2, UDFCD, June 2001
' "Urban Storm Drainage Criteria Manual". Volume 3. UDFCD, November, 2010
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ATTACHMENTS
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Hydrologic Soil Group—Larimer County Area, Colorado
(Discovery Fellowship Church)
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Conservation Service National Cooperative Soil Survey
10/31/2012
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Discovery Fellowship Church
drologic Soil Group— Summa b Map Unit- Larlmer County Area, Colorado (CO644)
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percent slopes
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76.9%
Totals for Area of Interest
5.6
100.0%
Description
Hydrologic soil groups are based on estimates of runoff potential. Soils are
assigned to one of four groups according to the rate of water infiltration when the
soils are not protected by vegetation, are thoroughly wet, and receive precipitation
from long -duration storms.
The soils in the United States are assigned to four groups (A, B, C, and D) and
three dual classes (A/D, B/D, and C/D). The groups are defined as follows:
Group A. Soils having a high infiltration rate (low runoff potential) when thoroughly
wet. These consist mainly of deep, well drained to excessively drained sands or
gravelly sands. These soils have a high rate of water transmission.
Group B. Soils having a moderate infiltration rate when thoroughly wet. These
consist chiefly of moderately deep or deep, moderately well drained or well drained
soils that have moderately fine texture to moderately coarse texture. These soils
have a moderate rate of water transmission.
' Group C. Soils having a slow infiltration rate when thoroughly wet. These consist
chiefly of soils having a layer that impedes the downward movement of water or
soils of moderately fine texture or fine texture. These soils have a slow rate of water
transmission.
Group D. Soils having a very slow infiltration rate (high runoff potential) when
thoroughly wet. These consist chiefly of days that have a high shrink -swell
potential, soils that have a high water table, soils that have a claypan or clay layer
' at or near the surface, and soils that are shallow over nearly impervious material.
These soils have a very slow rate of water transmission.
' If a soil is assigned to a dual hydrologic group (A/D, B/D, or C/D), the first letter is
for drained areas and the second is for undrained areas. Only the soils that in their
natural condition are in group D are assigned to dual classes.
' Rating Options
Aggregation Method., Dominant Condition
' Component Percent Cutoff. None Specified
USDA Natural Resources Web Soil Survey 10/31/2012
Conservation Service National Cooperative Soil Survey Page 3 of 4
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DESIGN WORKSHEET
Client: Discovery Fellowship Church
Project: Building Expansion
Task: Drainage / Detention Analysis
Job No.: 12-389
By: LCO
Checked:
Page: 1
Date: 10/30/12
Date:
of: 6
Storm runoff for the existing development of the church property was analyzed by Parsons &
Associates in 1992. The anticipated storm runoff from the developed property, as well as the
required detention capacity and an allowable rate of release from the property were determined,
based upon the Stormwater Design Criteria applicable at the time. Since that time, the City has
revised the stormwater design criteria and an expansion of the church facilities on the site is
proposed. Thus, it is necessary to reassess the stormwater regime for the site and to design
upgrades to the stormwater management improvements to cope with anticipated increased
runoff and to comply with current stormwater design criteria.
The overall nature of the site will not change as a result of the proposed expansion,
however, the total area of impervious surfaces will increase with the building expansion.
The area of the site is 5.001 acres. There is also a portion of the adjacent residential
properties to the south of the church site, comprising a total of approximately 0.61 acres, that
drains onto the site. This off -site tributary area will be included in the catchment area assessed
in this analysis. Runoff from areas west of the site (Brittany Drive, and other upstream areas of
the Provincetowne development) is intercepted and diverted to the north and around the site in
the street gutters or in existing stormwater systems. These upstream areas will not be included
in this analysis of the church site. For purposes of this drainage/detention analysis, the entire
site, as well as the off -site tributary area, are considered to be a single drainage basin, with a
total area of 5.612 ac. A small portion of the site, along the extreme east perimeter of the
property, and comprising approximately 0.035 acres, is beyond the ridge of the perimeter swale
and cannot practicably be captured and directed to the proposed on -site detention basin.
Runoff from this area will flow off the site undetained, as it currently does. This undetained flow,
however, will be compensated for in the design of the detention basin and outlet controls, such
that the net effect will be as if all of the runoff from the entire site, as well as the off -site tributary
area, is being detained.
The proposed expansion of the church facilities will likely occur in two or more phases. This
' analysis, however, anticipates the completion of all the proposed expansion components and
the stormwater management improvements resulting from this analysis have adequate capacity
of accommodate the full extent of the proposed facilities expansion.
I
' Client: Discovery Fellowship Church Job No.: 12-389
Project: Building Expansion Date: 10/30/12
' Task: Drainage / Detention Analysis Page: 2 of 6
Component Surface Areas and Runoff Coefficients
The aggregate areas and respective runoff coefficients and percent imperviousness of the
various surfaces within the tributary area (church site and adjacent off -site residential area),
upon completion of the proposed church expansion program, are presented below.
1
Surface
Area ac
Runoff Coefficient
% Im erviousness
Pavement
1.319
0.95
100
Bldg. Roof
0.432
0.95
90
Landscaped Area
3.861
0.15
0
Total / Composite
5.612
0.40
30.43
Time of Concentration
The site slopes from southwest to northeast. The average gradient across the site is
approximately 6.3%, however, due to development of the site, localized landscaped slopes near
the building are as steep as approximately 4:1 and landscaped slopes in other areas of the site
are in the range of 8:1 or 9:1. Expansion plans for the church will not change the overall
grading of the site. Localized slopes adjacent to the building will be similar to those currently
existing, with those on the north end being shifted further north to accommodate the expanded
building.
All storm runoff will migrate via overland sheet flow and shallow concentrated flow toward
the low point of the site, which is in the northeast corner of the property, where an on -site
detention basin will be located. The longest flow path to the detention basin is used to
determine the effective time of concentration for the overall drainage basin.
• Initial overland flow travels approx. 290.0' @ 7.6% avg. slope
' • Ti = 0.395 (1.1 — CfC)(L)o.5
58.33
' For the Minor Storm (2-yr), Cf = 1.00
• Ti = 0.395 (1.1 — (1.0)(0.40)) (290.0)0 5 = 11.02 mins
(0.076) .33
' For the Major Storm (100-yr), Cf = 1.25 .
' Ti = 0.395 (1.1 — (1.25)(0.40)) (290.0)05 = 9.45 mins
(0.076)0 33
' Subsequent concentrated flow in a shallow grassed swale travels approx. 625' at an
average gradient of approximately 3.7%. Flow velocity in a grassed swale at 3.7% is
' approximately 2.9 ft/sec.
1
1
1
1
1
1
1
1
1
1
1
DRAINAGE CRITERIA MANUAL (V. 1)
50
30
r 20
Z
W
V
S
W
4 10
W
a
o b
y
W
Ir 3
0
u 2
WLu
F
Q
1
.5
4.1 .2 .3 JY1111112 3 5 10
PER SECOND
3
1,
FIGURE RO-1
Estimate of Average Overland Flow Velocity for Use With the Rational Formula
0612001
Urban Drainage and FloodControlDistrict
RUNOFF
ON
III I
�■■■��i
����
i®���■����
ti���IQ�I�■■IIDm
20
1.14151141
I
' Client: Discovery Fellowship Church Job No.: 12-389
Project: Building Expansion Date: 10/30/12
' Task: Drainage / Detention Analysis Page: 3 of 6
• Tt = L = 625 = 3.59 mins
' V(60) 2.9(60)
Tc=Ti+Tt
• For the minor storm Tc = 11.02 + 3.59 =14.61 mins
• For the major storm: T. = 9.45 + 3.59 = 13.04 mins.
' Design Storm Runoff
Using the Rainfall Intensity -Duration -Frequency information presented in the City of Fort
' Collins Stormwater Criteria Manual (December 2011), the applicable rainfall intensity for a 2-
year storm event (12), with a duration of 14.61 minutes is 1.89 in/hr.
Applying this rainfall intensity to the Rational Method, the design runoff from a 2-yr storm
event impacting the tributary area of the site:
• QZ = C ' I ' A = (0.40)(1.89)(5.612) = 4.24 cfs
1 The applicable rainfall intensity for a 100-year storm event (1100) with a duration of 13.04
minutes is 6.91 in/hr. Therefore, the design runoff from the tributary area of the site for the 100-
' year storm event:
Q10o = Cf.C. I ' A = (1.25)(0.40)(6.91)(5.612) =19.39 cfs
' Allowable Release Rate from Detention Basin
' The Final Drainage & Erosion Control Report for Redeemer Lutheran Church (now the site
of Discovery Fellowship Church), prepared in 1992 by Parsons & Associates, established that
the historic 100-yr runoff from the undeveloped church site, and the allowable release rate from
' the then -proposed on -site detention facilities, was 7.62 cfs. The detention basin contemplated
in the Parsons report, was apparently never constructed, but it is reported that the conveyance
improvements downstream of the site were constructed to accommodate the design runoff and
more.
An on -site detention basin will be constructed as part of the church expansion addressed in
this current analysis, and the historic runoff rate established in the Parsons report will be
adopted and used in this current analysis to determine the size of the detention basin required
to accommodate the proposed improvements to the church property.
' Required Detention Capacity
The detention capacity required to attenuate the 100-yr storm runoff is determined using the
' Modified Rational Method. For purposes of this analysis, the tributary drainage basin is
a`
gol
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gg
ag
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11
air
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(Jy/ui) Allsua;ul
' (11) Section 4.0 is amended to read as follows:
4.0 Intensity -Duration -Frequency Curves for Rational Method:
' The one -hour rainfall Intensity -Duration -Frequency tables for use the Rational Method
of runoff analysis are provided in Table RA-7 and in Table RA-8.
Table RA-7 -- City of Fort Collins
.1
1
1
1
1
1
1
1
Rainfall Intensity -Duration -Frequency Table
for Use with the Rational Method
(5 minutes to 30 minutes)
Duration
(min)
5
2-Year
Intensity
(in/br)
2.85
10-Year
Intensity
(in/hr)
4.87
100-Year
Intensity
(in/hr)
9.95
6
2.67
4.56
9.31
7
2.52
4.31
8.8
8
2.4
4.1
8.38
9
2.3
3.93
8.03
10
2.21
3.78-
7.72
11
2.13
3.63
7.42
12
2.05
3.5
7.16
13
1.98
3.39
6.92
14
1.92
3.29
6.71
15
1.87
3.19
6.52
16
1.81
3.08
63
17
1.75
2.99
6.1
18
1.7
2.9
5.92
19
1.65
2.82
5.75
20
1.61
2.74
5.6
21
1.56
2.67
5.46
22
1.53
2.61
5.32
23
1.49
2.55
5.2
24
1.46
2.49
5.09
25
1.43
2.44
4.98
26
1.4
2.39
4.87
27
1.37
2.34
4.78
28
1.34
2.29
4.69
29
1.32
2.25
4.6
30
1.3
2.21
4.52
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Table RA-8 -- City of Fort Collins
Rainfall Intensity -Duration -Frequency Table
for Use with the Rational Method
(31 minutes to 60 minutes)
Duration
(min)
31
2-Year
Intensity
(ice)
1.27
10-Year
Intensity
(ice)
2.16
100-Year
Intensity
(inftu)
4.42
32
1.24
2.12
4.33
33
1.22
2.08
4.24
34
1.19
2.04
4.16
35
1.17
2.0
4.08
36
1.15
1.96
4.01
37
1.16
1.93
3.93
38
1.11
1.89
3.87
39
1.09
1.86
3.8
40
1.07
1.83
3.74
41
1.05
1.8
3.68
42
1.04
1.77
3.62
43
1.02
1.74
3.56
44
1.01
1.72
3.51
45
0.99
1.69
3.46
46
0.98
1.67
3.41
47
0.96
1.64
3.36
48
0.95
1.62
3.31
49
0.94
1.6
3.27
50
0.92
1.58
3.23
51
0.91
156
3.18
52
0.9
154
3.14
53
0.89
1.52
3.1
54
0.88
15
3.07
55
0.87
1.48
3.03
56
0.86
1.47
2.99
57
0.85
1.45
2.96
58
0.84
1.43
2.92
59
0.83
1.42
2.89
60
0.82
1.4
2.86
' Client: Discovery Fellowship Church Job No.: 12-389
Project: Building Expansion Date: 10/30/12
' Task: Drainage / Detention Analysis Page: 4 of 6
deemed to include both the entire area of the project site, as well as the adjacent off -site area
that is tributary to the site. The attached spreadsheet shows that the attenuation volume
' required is 0.233 ac-ft (10,169 c.f.), which occurs for a 100-yr storm with a duration of at least
20 minutes.
' The design runoff from the site to the detention basin resulting from the 2-yr storm event is
less than the allowable release rate from the detention basin A = 4.24 cfs compared to
Qall abie = 7.62 cfs). Therefore, it appears unnecessary to provide for detention of the 2-yr storm
' runoff.
In addition to attenuation of storm flows, the detention basin is also designed to provide
water quality enhancement, particularly of the initial runoff flows. Per the UDFCD criteria, the
detention capacity that is required for water quality enhancement (the water quality capture
volume or "WQCV") is calculated as follows:
' • WQCV = A"R / 12, where R is a function of the composite % imperviousness of the site.
• 1 = 30.43% i = 0.3043
• R =0.91 i3-1.19i2+0.78i
' = 0.153 in
• WQCV=5.612.0.153/12
= 0.072 ac-ft (3,113 c.f.)
' • Allowing 20% increase for sedimentation, results in total required volume = 0.086 ac-ft
(3,735 c.f.)
In summary, the detention capacities required for the respective storm events, as well as
WQCV, are as follows:
• WQCV 0.086 ac-ft (3,735 c.f.)
• WQCV + 100-yr storm runoff attenuation 0.319 ac-ft (13,885 c.f.)
' Available Detention Capacity
The on -site detention basin will be created in the northeast corner of the site by excavation
' of native soils and placement, compaction and shaping of the excavated soils in perimeter
embankments. The configuration of the detention basin is shown on the Grading & Drainage
Plan for the project.
' The attached Detention Basin Depth -Capacity Analysis worksheet shows that the respective
detention capacities will be satisfied at water surface elevations (WSE's) as follows:
' WQCV 4,926.24 ft
WQCV + 100-yr storm runoff attenuation: 4,928.75 ft
' The top elevation of the perimeter impoundment berms of the detention basin will be
4,930.00 ft, to provide a minimum freeboard height of 1.28 ft above the design WSE for the
WQCV + 100-yr storm runoff attenuation.
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DETENTION BASIN DEPTH -CAPACITY ANALYSIS
Project No.: 12-389
Project Name: Discovery Fellowship Church
Basin I.D.: On -site Detention Basin
Date: 11/2/12
Contour
Plan
Depth
Volume
Cummulative
Elevation
Area
Interval
Increment
Volume
amsl
s.f.
ft
c.f.
c.f.
ac-ft
4924.15
5
0.00
0.00
0.00
0.000
4925.00
2 036
0.85
607.01
607.01
0.014
4926.00
2 760
1.00
2,389.02
2,996.03
0.069
4927.00
3 584
1.00
3,162.89
6,158.92
0.141
4928.00
4 491
1.00
4,028.80
10 187.71
0.234
4929.00
5 467
1.00
4,971.11
15 158.82
0.348
4930.00
6 531
1.00
5.991.27
21 150.09
0.486
4931.00
a±
4930.00
0 4929.00
4928.00
w 4927.00
'0 4926:00
o 4925.00
4924.00
4923.00
0.000 0.100 0.200 0.300 0.400 0.500 0.600
Detention Volume (ac-ft)
-The required aggregate detention volume of 0.319 ac-ft for the 100-yr storm attenuation plus
WQCV is satisfied at a water surface eleVn of:
- The required detention volume of 0.086 ac-ft for the WQCV is satified at a water
surface eleJn of:
4928.76
4926.24
I
' Client: Discovery Fellowship Church Job No.: 12-389
Project: Building Expansion Date: 10/30/12
' Task: Drainage / Detention Analysis Page: 5 of 6
Outlet Control Structure and Discharge Piping
' An outlet control structure will be constructed within the detention basin to regulate the rate
of release of accumulated stormwater runoff from the detention basin. The outlet control
structure will be as shown on the Drainage & Detention Details drawing included in the project
' drawing set.
The outlet control structure will include two orifice plates; one to control the release of the
' initial flows that enter the detention basin (the WQCV portion of the accumulated runoff), and
the other to control the release of the accumulated runoff from the 100-yr storm event. The
WQCV orifice plate will include a column of small -diameter holes, and will be installed on the
upstream, inner face of the outlet control box to regulate the release of the accumulated runoff
at the lowest levels of the basin. The small diameter holes in the WQCV orifice plate will be
protected from debris clogging by installation of a filtering trash rack on the outer face of the
' outlet control structure, across the opening immediately upstream of the orifice plate. Details
and configuration of the orifice plate and trash rack are shown on the Drainage & Detention
Details drawing.
t The 100-yr orifice plate will include a larger circular hole, and will be installed on the
downstream interior face of the outlet control structure, so that it becomes active as a
constriction only after the depth of water in the detention basin exceeds the level of the WQCV
' and spills into the interior of the outlet control structure.
Flows in excess of the 100-yr runoff will spill over the emergency spillway, and into the
' adjacent street.
WQCV Orifice Sizing
' Required WQCV = 0.086 ac-ft
• WQCV water surface elevation = 4926.24 feet
' WQCV depth = 2.20 feet (4926.24 — 4924.15)
• UDFCD criteria for circular orifice openings in a WQCV outlet control plate provides the
following:
• For H = 2.09 ft
' K4o = 0.013Dwo2 + 0.22 Dv4Q — 0.10 = 0.013(2.09)2 +0.22(2.09) — 0.10 = 0.417
• Ao = WQCV / K4o = 0.086 / 0.417 = 0.206 in2 / row
• Do = 0.512 inches (-1/2" dia.).
' Specifying Do = 0.512 inches in a single column of 6 holes, will achieve discharge of the
WQCV in a period of 40 hours. Specifying an orifice diameter of 0.50" will result in a
discharge period of only slightly longer than 40 hours.
' The WQCV outlet control orifice plate will be specified with a single column of 6 holes
spaced at 4 inches center to center, and each hole being 0.50 inch diameter.
' 100-vr Storm Outlet Control Orifice Sizing
' Required orifice size is determined from the equation:
I
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G
1
L
1
Client:
Discovery Fellowship Church
Job No.:
12-389
Project:
Building Expansion
Date:
10/30/12
Task:
Drainage / Detention Analysis
Page:
6 of 6
Q = Ca(2gh)05 or a = Q
C (2gh)o.s
• Qalle ble = 7.62 cfs
• C = 0.62
• g = 32.2 ft/sec2
• h = 4928.75 — 4925.40 = 3.35 ft (Assumes HGL for 15" dia. discharge pipe flowing full.)
• Therefore, required opening area "a" = 7.62 = 0.837 ft2
0.62(2 x 32.2 x 3.35) .5
• Orifice diameter = 1.03 ft = 12.39 in (Recommend 12 318 in diameter)
Discharge Pipe Capacity
• Maximum design discharge through discharge pipe = 7.62 cfs
• Portion of existing pipe that was truncated to divert parking lot runoff into detention basin will
be removed, salvaged and a portion relayed to serve as discharge pipe from OCS to
existing manhole.
• Discharge pipe will be laid at 0.80% to convey allowable discharge without surcharging pipe.
• 15" HDPE N-12 pipe at 0.80% slope has a capacity of approx. 7.6 cfs
• Therefore, discharge pipe has adequate capacity to convey maximum design flow.
Emergency Overflow
In order to safely convey storm runoff through the detention basin that may be in excess of
the design 100-yr storm flow, an emergency overflow spillway will be constructed in the north
berm of the detention basin. The overflow spillway will have a sill elevation of 4928.75 ft.,
leaving a freeboard allowance of 1.25 ft to the crest of the perimeter berms.
The spillway will act as a Cipolletti weir. Analysis of various weir lengths indicates that a
crest length of 15.0 feet will pass the peak design inflow rate for the 100-yr storm event (19.39
cis), with a surcharge head of 0.52 ft. (6.24 in.), as shown on the attached worksheet. This
leaves a freeboard of 0.73 ft (8.76 in.).
Excess flows passing over the emergency spillway will be conveyed down the embankment
slope the adjacent street (Trilby Ave.) where it will flow east in the street gutter and ultimately to
Fossil Creek.
I
Discovery Fellowship
Church - Emergency
Overflow Weir
Solve For Headwater Elevation
Discharge
19.39
ft-/s
Crest Elevation
4928.75
ft
'
Tailwater Elevation
4926.00
ft
Weir Coefficient
3.40
US
t
Crest length
15.00
ft
_
-7='_
R77
U St
Headwater Elevation
4929.27
ft
'
- Headwater Height Above Crest
- 0.52
ft
Taihvater Height Above Crest
-2.75
It
'
Equal Side Slopes
0.25
Wit(H:V)
Flow Area
7.94
ft-
Velocity -
2.44
ft/s
'
Wetted Perimeter
16.08
ft
Top Width
15.26
ft
t
I
' Bentley Systems, Inc. Haestad Methods SoO7tlafltBeffillinrMaster V61(SELECTseries 1) 106.11.01.07]
11/5/201212:29:47 PM 27 Simms Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 Page 1 of 1
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STORMWA TER MANAGEMENT PLAN
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Discovery Fellowship Church
Facilities Expansion
Fort Collins, Colorado
STORMWA TER MANAGEMENT PLAN
and
EROSION CONTROL PLAN
Prepared For:
Discovery Fellowship Church
6630 Brittany Drive
Fort Collins, CO 80525
(970)204-6787
Prepared By:
0 OWEN
CONSULTING
GROUP, INC.
3715 Shallow Pond Dr., Fort Collins, CO 80528
Phone:970-226-0264 Fax: 970-226-3760
larrycowen@comcast.net
Revised August 2013
Revised May 2013
November2012
Proj. No.: 12-389
1
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' DISCOVERY FELLOWSHIP CHURCH
FORT COLLINS, COLORADO
' FACILITIES EXPANSION
STORM WATER MANAGEMENT PLAN
and
EROSION CONTROL PLAN
' Site and Project Description
' The project site, which is currently developed with a main church building and an auxiliary
trailer, used as a youth meeting facility, comprises approximately 5.00 acres. The site is located
on the southeast corner of the intersection of Trilby Road and Brittany Drive in Fort Collins, CO.
The site is part of the NE '% of Section 13, Township 6 North, Range 69 West of the 6t" Principal
Meridian, City of Fort Collins, Larimer County, Colorado. The site is bounded on the west by
Brittany Dr. and residential development; on the north by Trilby Rd., and another church
property; on the east by a multi -family residential complex, and on the south by single-family
residential development.
The expansion of the church facilities will include a two-story youth wing, with a footprint area of
' approximately 4,500 s.f., and a two-story addition to the existing sanctuary, with a footprint area
of approximately 3,200 s.f. The current youth trailer, covering approximately 840 s.f. will be
removed upon completion of the new youth wing. There will be no changes made to the
1
existing driveway and parking area.
Specific construction activities to be completed during the course of development will include
some overlot grading; excavation for and construction of the building expansions; construction
of the on -site detention basin; final grading; and installation of landscaping materials. The
layout of the proposed development is shown on the attached Grading & Drainage
Improvements Plan.
The surface gradient of the site averages approximately 6.3%, sloping from southwest to
northeast. Existing site drainage is almost exclusively via overland flow, with the runoff from the
southwest quadrant of the site and the parking area being directed to a curb inlet and piped to
the discharge point at the northeast corner of the site. There is currently no on -site detention
basin serving the property. Runoff flows from the site, undetained, passes beneath the
driveway serving the adjacent multi -family residential complex to the east, and into an open
channel that conveys the flow to a detention facility at the northeast corner of the multi -family
residential property, and then beneath Lemay Ave and on to Fossil Creek.
The native soils underlying the site are Renohill clay loam (77%), in the western and northern
regions, and Kim loam (23%) along the eastern perimeter of the site. The Renohill clay loam
falls within NRCS Hydrologic Soil Group C"and the Kim loam falls within Group B. The extent
and distribution of the underlying soils are shown in the attachments to the Final Drainage
Report for the project.
At the current state of site build -out, the composite Runoff Coefficient for the site would range
between approximately 0.37 and 0.47, depending on storm intensity. Upon completion of the
proposed building expansion, the composite 100-yr Runoff Coefficient for the site, "Cloo", is
Discovery Fellowship Church 1 11/19/2012
Storm Water Management Plan Revised: 8/05/2013
' calculated to be 0.50 and the composite Percent Imperviousness of the site is calculated to be
30.43%.
' The general sequence of development activities at the site will include limited overlot grading;
construction of the new detention basin; excavation for and construction of building expansions;
' final grading; and landscaping of the open -space areas of the site. During the course of
development, at one time or another, approximately 25% of the site will be disturbed.
' The primary source of potential surface water contamination that may result from development
of the site is sediment that will be liberated due to construction operations. Other lesser
potential sources of contamination may include hydrocarbons from on -site fueling and servicing
of construction vehicles and equipment, as well as particulate and trace chemicals from
' concrete and building construction activities. There are no other known or anticipated sources
of contamination that may impact the site runoff and downstream receiving waters.
' Runoff from the site will be collected and conveyed to the on -site detention basin, designed to
provide storm attenuation and water quality enhancement for the developed site, and
constructed as an initial part of the construction program. Site runoff accumulated in the
' detention basin will eventually be discharged from the outlet control structure at the northeast
corner of the site to the downstream channel, and from there to Fossil Creek, and ultimately into
the Cache !a Poudre River.
' Construction Activities
' As indicated above, approximately 25% of the site (a total of approximately 1.25 acres) will likely
be disturbed during the course of building expansion and detention basin construction, due to
overlot grading; construction of the building expansions; or final grading and landscaping. There
will likely be a surplus of excavated soil from the construction activities, so on -site stockpiling of
' soil will be a temporary necessity, and there will be a subsequent need to haul excavated
material off -site to a disposal facility. Stockpile height will be limited to a maximum of ten feet,
and stockpiles will be located as far as possible from any interim on -site drainage ways. Any
' concrete removed during demolition activities will either be disposed of in an approved facility or
recycled.
' Construction materials will generally be delivered to the site as they are required, and stored in
close proximity to the work area or immediately incorporated into the permanent construction.
Imported construction materials will, for the most part, be non-polluting (steel, concrete, brick,
clean fill or construction aggregate, lumber, finishing materials, etc.). There will not be any
dedicated asphalt or concrete batch plants on -site.
' Wherever possible, excavated native soils will be used for backfill, and this material will be
stockpiled adjacent to the excavation and reused as quickly as practicable in a tight operation.
Precautions will be taken, as described below, to limit erosion and transport of temporarily
' stockpiled material.
Best Management Practices (BMPs) for Erosion Control and Stormwater Pollution Prevention
' Erosion and sediment transport from disturbed areas of the site present the most significant
potential for contaminant migration during construction activities at the site. Several structural
BMPs, common to most construction sites, will be implemented to limit this potential and to
' mitigate impacts, as follows:
Discovery Fellowship Church 2 11/192012
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• Silt fencing will be installed along the north and east perimeters of the site, prior to initiation
of any soil disturbance. The silt fences will be maintained throughout the course of
construction activities.
• Temporary diversion berms will be constructed along the uphill perimeter of any site areas
that are to be disturbed, in order to minimize the inflow of runoff from outside areas to the
construction sites.
• Within the disturbed areas, the surface of exposed soils will be roughened along an
alignment that follows the site contours, to limit the flow path length of runoff water and to
promote infiltration of stormwater into the exposed soils.
• Where necessary, exposed soils will be stabilized with mulch or other approved methods, to
stabilize the exposed surface and limit erosion.
• Temporary drainage swales will be established within the site, as necessary, to intercept
and divert storm runoff, and temporary sediment traps (silt fence, wattles, or other approved
materials) will be installed at regular intervals along the lengths of these temporary swales to
slow the velocity of runoff flows and to promote deposition of sediment and other suspended
solids.
• The permanent stormwater detention basin, which will have capacity to detain the runoff
expected from the 100-year storm impacting the entire tributary area of the site and the off -
site tributary area, will serve as a construction sediment trap. All runoff from the site will be
directed to the detention basin, and discharge from the detention basin will be controlled. A
silt -fence sediment trap will be constructed within the detention basin, immediately upstream
of the outlet control structure, to intercept sediment and confine it to the detention area. This
sediment trap will be regularly maintained and accumulations of sediment generated from
the site will be removed and properly disposed of.
• Inlet protection will be installed at all storm drain inlets into which runoff from the site might
flow.
A vehicle tracking control pad will be constructed at the site construction access point (to be
determined) to limit transport of mud or soil clods from the site onto the public streets via
truck tires.
Existing pavement will be swept and/or flushed, as necessary, to remove dirt and/or debris
that might be tracked beyond the site by local traffic.
In addition to the structural BMPs listed above, several non-structural BMPs will also be
implemented as part of the construction program, in order to limit erosion and sediment
transport.
• The construction activities will be advanced in a manner designed to maintain a compact
' scope of construction activities within the site at any given time.
• Construction activities will be kept tight and excavations will be backfilled as promptly as
practical, in order to limit the number and extent of exposed temporary soil stockpiles.
' Soil stockpiles and other exposed soils will be wetted, as necessary, to control dust
generation.
• Where it is necessary to have soil stockpiles or other significant areas of exposed soil on
t site for an extended period of time, consideration will be given to applying synthetic covers
or durable, membrane -forming surfactants on these surfaces, to limit the potential for
erosion or dust generation.
' In addition to soil erosion and sediment transport, a further, but considerably lesser risk of
contaminant migration may be presented due to spills or leaks during equipment fueling and
' maintenance, materials handling and storage, or waste disposal. Equipment fueling and
Discovery Fellowship Church 3 11/19/2012
Storm Water Management Plan Revised: 8/05/2013
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maintenance will be ongoing daily activities, throughout the course of construction activities.
However:
' On -site storage of bulk fuels, lubricants and solvents will be minimized.
• Where practicality and efficiency necessitate having a certain supply of such potential
' contaminants on -site, they will be stored in approved containers and at locations well
removed from drainage flow paths.
• If bulk fuel is stored on -site, approved secondary containment facilities will be established at
' the storage location.
• Fueling and servicing of vehicles and equipment will be conducted in areas that are away
from drainage swales and other potential runoff flow paths.
' In the event of a spill or leak during fueling or servicing, contaminated soils will be promptly
collected and properly secured or disposed of in an approved facility. In addition,
appropriate notification will be given and documentation of the cleanup maintained. Contact
numbers for project personnel are provided at the end of this SWMP.
1 Materials and supplies will be delivered to the site on an ongoing basis to support construction
activities. Appropriate handling and storage procedures will be implemented to limit any
' potential for contamination of storm water being discharged from the site.
• Most materials will be delivered to the site as they are needed, and will be promptly
' incorporated into the permanent works.
• There will be very little on -site materials storage, and only a small percentage of those
materials that are stored on -site will constitute a potential source of contamination.
' If it becomes necessary to store potentially hazardous or contaminating materials on -site,
they will be stored in a secure, protected area to minimize the risk of exposure or migration.
As necessary, indoor or covered storage will be provided, and secondary containment will
be established.
' Handling and disposal of waste and debris will also be regulated in order to avoid creation of
unnecessary sources of potential contamination.
• All subcontractors will be required to maintain a neat and tidy operation, regularly cleaning
up and removing excess materials, construction spoil and debris.
' Sanitary waste facilities (Porta-Potties) will be located away from drainage channels and will
be regularly maintained and serviced.
• All subcontractors will be required to dispose of construction waste in approved, covered
containers, which will be regularly removed from the site to an approved waste disposal
facility.
• Clean-up or decontamination of construction equipment, including washout of concrete
' mixers, will be performed in a designated area of the site, well removed from drainage paths
and storm water management facilities.
• Potential contaminants from such activities will be contained and, if necessary, collected for
appropriate disposal.
Final Site Stabilization and Long -Term Storm Water Management
' As soon as practicable, after completion of construction activities at the site, permanent
landscaping will be installed including trees, shrubs, seeding, sodding, filter fabric, mulch and
plant materials, per the approved Landscape Plan.
' Discovery Fellowship Church 4 11/19/2012
tStorm Water Management Plan Revised: 8/05/2013
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Disturbed areas of the site will be prepared and revegetated in accordance with the
Revegetation Specification attached to this Stormwater Management and Erosion Control Plan.
If climatic conditions, at that time, are not suitable for planting and timely establishment of new
vegetation, interim measures will be taken to limit the potential for erosion and sediment
transport, and such measures will be maintained until permanent actions can be effectively
implemented. Such interim measures may include mulching or application of surfactants,
particularly on areas that may be prone to erosion.
Inspection and Maintenance of Storm Water Management Facilities
All BMPs, and the site in general, will be inspected at least every 14 days, as well as after
significant storm events throughout the construction period, in order to assess the condition of
storm water management facilities and identify any need for maintenance, repair or replacement
of such facilities, to ensure their continued effectiveness. The frequency of regular inspections
will be not less than bi-weekly. During such inspections, particular attention will be given to
BMPs and other preventative measures where the risk or consequence of a failure is greatest
(e.g., in proximity to materials of significant concentration or toxicity, or closest to the site
discharge point, etc.). All inspections will be fully documented and records will be maintained
on site for reference and confirmation.
If a need for maintenance, repair or replacement of BMP's is identified, the nature of the
problem will be documented, along with recommended actions and a timeline for completion of
the work. A follow-up inspection will be made to ensure that appropriate actions have been
taken to ensure the continued adequacy and effectiveness of the storm water management
system. The follow-up inspection will also be documented and filed with the original inspection
report.
Specific inspection and documentation will also be implemented after any extraordinary incident
or event, such as a spill or leak, with appropriate follow-up to ensure effective containment and
clean-up. The documentation of such an event will also address measures or procedures to be
implemented to avoid a recurrence.
In addition to inspection and incident reports, storm water management system records will also
include:
• Documentation of the implementation or removal of BMPs.
• Records of communications or correspondence with regulatory personnel
• Details of and authorization for modifications to the SWMP
• Maintenance and repairs records
• Details of preventative maintenance activities
• Pertinent photos, sketches and field memos.
Contact Information
The following individuals will be available for contact in the event of an on -site incident, or to
respond to questions regarding the implementation and/or compliance with this SWMP. In the
event that these individuals are no longer associated with the project, or when changes or
additions are made to the relevant contact information, an addendum to this SWMP will be
prepared providing updated information, and that addendum will be incorporated into the
original and all copies of the document.
Discovery Fellowship Church 5 11/19/2012
Storm Water Management Plan Revised: 8/05/2013
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• Owner:
Discovery Fellowship Church
6630 Brittany Drive
Fort Collins, CO 80525
970-204-6787
Att'n: Craig Crider
• Contractor
Roche Constructors, Inc.
361 — 71 sc Ave
Greeley, CO 80634
(970) 356-3611
Att'n: Bob Lyions — Project Mgr. (970-409-6403)
• Civil Engineering Consultant
Owen Consulting Group, Inc.
3715 Shallow Pond Drive
Fort Collins, CO 80528
970-226-0264
Att'n: Mr. Larry Owen, P.E.
In addition to the personnel listed above, the following agencies may/should be contacted in
certain situations:
• For emergencies, always dial 911
Discovery Fellowship Church
Storm Water Management Plan
11/19/2012
Revised: 8/05/2013
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DISCOVERY FELLOWSHIP CHURCH
Fort Collins, Colorado
STORM WATER MANAGEMENT PLAN
INSPECTION REPORT (Page 1 of 2)
Inspections/reports must be completed at least every fourteen (14) days and within 24 hours following
any rainfall or snowmelt event that causes erosion.
Inspection Type: ❑ Routine (every 14 calendar days) ❑ Pre -Storm ❑ Storm ❑ Post -Storm
Date: Week Ending:
Weather/Storm Event Information:
Storm Start Time: Stonn Duration:
Time Elapsed Since Last Storm: Approximate Amount of Rainfall (inches):
Based on the results of the inspection, necessary control modifications shall be implemented within _seven (7)
calendar days. These reports shall be kept on file as part of the Storm Water Pollution Prevention Plan for at least
five (5) years from the date of completion and submission of the Final Stabilization Certification/Termination Checklist
and Notice of Termination. A copy of the SWMP shall be kept at the site at all times during construction.
Certification Statement:
"I certify under penalty of law that this document and all attachments were prepared under my direction or supervision
in accordance with a system designed to assure that qualified personnel property gathered and evaluated the
information submitted. Based on my inquiry of the person or persons who manage the system, or those persons
directly responsible for gathering information, the information submitted is, to the best of my knowledge and belief,
true, accurate, and complete. I am aware that there are significant penalties for submitting false information,
including the possibility of fine and imprisonment for knowing violations."
Name of Inspector: Title of Inspector:
' Qualifications of Inspector.
' Inspector's Signature:
Construction phasing/sequencing is consistent with the SWMP and Erosion Control Plans: Yes No
' Compliance Certification
I certify that, based on there being no incidents of noncompliance Identified during the Inspection, the site is
in compliance with the SWMP and the Construction General Permit
' Name of duty authorized representative (Printed):
Signature of duly authorized representative:
' Date:
`Note: This Compliance Certification is only to be signed by a duly authorized representative (Project Manager) when
' there are no "unsatisfactory" conditions and the construction phasing/sequencing is consistent with the SWMP,
rendering the site in full compliance with the SWMP and the Construction General Permit.
' Discovery Fellowship Church, Fort Collins, CO - PAGE 1 OF 2
11/19/12
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REVEGETATION SPECIFICATION
Disturbed areas of the site shall be prepared and revegetated in accordance with the
following specification.
Clearing and Site Preparation
Prior to any soil preparation, existing vegetation, which is to remain and which might
interfere with the specified soil preparation, shall be mowed, grubbed, raked and the debris
removed from the site. Prior to, or during grading or tillage operations, the ground surface shall
be cleared of materials that might hinder final operations.
Rip all areas to be planted, seeded and/or sodded to a minimum depth of 8 inches in two
directions, using an agricultural ripper with tines spaced at no greater than 18 inches. Areas
adjacent to walks, structures, curbs, etc., where the use of large mechanical equipment is
difficult, shall be worked with smaller equipment or by hand.
Soil Preparation
Spread compost at an application rate of 3 c.y. / 1,000 s.f. and fertilizer in accordance with
manufacturer's recommendations, over all areas to be seeded, sodded and/or planted with
trees, shrubs or ground cover. Incorporate compost by disking or rototilling into the top six
inches minimum of soil. Obtain a uniform mixture, with no pockets of soil or amendments
remaining.
Restore the fine grade of all areas to be planted, seeded and/or sodded, with float drag to
remove irregularities resulting from tilling operations. Float drag in two directions. Remove any
stones over 1 1/2 inches in diameter that have come to the surface. Upon completion of finish
grading operations, the Contractor must provide a finished landscape grade that conforms to the
grades and elevations shown on the engineering drawings. The Contractor shall ensure that
the grade promotes positive drainage in all landscaped areas.
Compost
Compost shall be a totally organic product that has been aerobically and naturally
processed, without the addition of coarse wood chips, to create the following characteristics,
measured by dry weight:
• Maximum allowable organic matter: 60%
• Organic matter to nitrogen ratio: 25:1 to 30:1
• pH 7to8
• pH Salts 2.0 to 3.0
• Inorganic matter: Less than 25%
• Soil, dirt or sand maximum particle size: '% in diameter
Fertilizer
Fertilizer for turf shall be commercial type, of uniform composition, free -flowing, and
conforming to applicable State and Federal laws. Contractor shall submit formulated
Manufacturer's guaranteed analysis.
I
Seed
' All seeding shall be completed between April 15 and May 31, or between September 1 and
October 15. Seeded turf areas shall be seeded with the following blend, at an application rate
' of 5 Ibs / 1,000 s.f.:
• Ward Bluegrass 30%
' Sandberg Bluegrass 25%
• Rocky Mountain Fescue 25%
Sheep Fescue 25%
' After seeding, the area shall be crimped with straw and provided with permanent irrigation.
The Contractor shall monitor the seeded area to ensure that the area is being properly irrigated,
t that seed germination and establishment is occurring, and that erosion protection BMP's remain
effective. Reseeding shall be implemented, as necessary, to obtain even coverage of grass.
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Mulch
Mulch shall be applied at a rate of two tons / acre (4,000 Ibs / ac), and shall be mechanically
crimped to a depth of two inches, using a purpose -made crimper. Where mechanical crimping
is not possible, mulch shall be hand crimped and covered with a tackifier. All mulch shall be
crimped such that the individual pieces of straw or hay form exaggerated V-shapes, protruding
out of the ground several inches.
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DRAWINGS
LEGAL DESCRIPTION
ALL REDEEMER LUTHERAN POD
OWNER / APPLICANT
DISCOVERY FELLOWSHIP CHURCH
0030 BR17AW OR.
FORT DOWNS, CO SI
(970)2016287E
ATPN'. RICK MANIDY
ENGINEERING CONSULTANT
OMEN CONSULTING GROUP, INC.
3715 SHALLOW POND CHUMS
FORT COLLINS, D000525
(970)MH0284
ATTR LARRY OKEN, P.E.
GENERAL NOTES
1. THE CITY OF FORT COLLINS SHALL NOT BE RESPONSIBLE FOR THE MAINTENANCE OF STORM
ORAINAGEFACILITIESLOCATEDONMIIVATEPROPERTY. MAINTENANCECFONSITEDRAINAGE
FACILTIES, INCLUDING BUT NOT LIMITED TO THE DETENTION IWATER OWLITV BASIN OUTLET
CONTROL STRUCTURE AND APPURTENANCES $HALL BE PRIVATELY OMTED AND MAINTAINED
BY THE PROPERTY OMER. THE PROPOSED STORM IMPROVEMENTS IDENTIFIED ON THE PLANS
ARE PRIVATE.
2. ALL RECOMMENDATIONS OF THE FINAL DRAINAGE AND EROSION CONTROL REPORT,
PREPARED BY OMEN CONSULTING GROUP, INC.. SHALL BE FO LOWED AND IMPLEMENTED.
3, PRIOR TO FINAL INSPECTION AND ACCEPTANC BY THE CITY OF FORT DOWNS,
CERTIFICATION OF THE DRAINAGE FACILITIES, BY A REGISTERED PROFESSIONAL ENGINEER,
SHALL BE SUBMITTED TO AND APPROVED BY THE STCRMNATER UTILITY DEPARTMENT.
CERTIFICATION SHALL BE SUBMITTED TO THE STORMWATER DR U Y DEPARTMENT AT LEAST
TVA) M II PRIOR TO THE RELEASE OF A CERTIFICATE OF OCCUPANCY.
DISCOVERY FELLOWSHIP CHURCH
REDEEMER LUTHERAN P.U.D.
PROPOSED BUILDING EXPANSION
SITE GRADING & DRAINAGE IMPROVEMENTS
A portion of the Northeast Quarter of Section 13, Township 6 North, Range 69 West of
the 6th Principal Meridian, City of Fort Collins, County of Larimer, State of Colorado
6630 Brittany Drive, Fort Collins, CO 80525
VICINITY MAP SCALE: NIS
vvn Ivry mI
BENCHMARK INFORMATION
VEIRICAL DATUM:
BENCHMARK. CITY OF FORTCOLLIN9 N0. 3481, ff ALLMINUN CAPLOCATEp APpgX. 13W
WEST OF NORTHWEST PROPERTY CORNER ALONG TRILBY AND ELEVATION • 5957.50
BENCHMARK. CITY OF FORT COLLINB NO 25W NW CORNER OF TRILBY RED, AND IEMAY AVE.
SOUTHEAST EDGE OF OONC. RIM OF ELEC. MANgLE ELEVATION=<P0P8T
LOCAL EucF%
IRON ROD a CAP MARKED 20372. ELEV•AIM2.1A
N.W. PROPER CORNER:
N.E. PROPERTY CORNER'.
IRON ROD a RED CAP MNMED SON. BUSY .4525.06
&IM PROPERTYCORNER.
ROD a CAP MARKED29R, ELEV.-4914.22
S E. PROPERTY CORNER:
IRON ROD a DAP MAWED 253T2. ELEV =aWL00
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PAGEINDEX
1. TITLE SHEET
]. OVERALL DRAINAGE PLAN AND EROSION CONTROL MN
3. SITE GRADING& MANAGE IMPROVEMENTS
A. DRAINAGE S DETENTION DETAILS
a EROSION CONTROL DETAILS
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APPROVAL SIGNATURES
ALL CONSTRUCTION SHALL BE IN ACCORDANCE WITH THE CITY OF EMT U d V
COLUNS STORMWATERCRITERMMANUAL. CITYACCEFTANCESHALLNOT y R:
RELIEVE THE DESIGN ENGINEER OF RESPONSIBILITY FOR ERRORS, F
OMISSIONS OR DESIGN DEFICIENCIES FORNMICHTHECITYISHELD y IX
HARMLESS. fo
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City of Fort Collins, Colorado
UTILITY PLAN APPROVAL
APPROVED:
OM"Immir Mb O
CHECKED BY: y
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CHECKED BY:
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LINdVEIMPRO,P. E..NTS TO THE AT REDEEMER LANSFORTHE K URE UCTION PREPARED
BY ME, OR
AND
DIRECT SUPERVISION
LUTHERAN PUB P HIP CHURL ME IXI UNDER MY
DIRECT BUPERPSION, FO0. TXE DMMER$TgE0.EDF, pI3CDYERY FELLOWSHIP CHURCH V
II
LARRYOOAEN, RE LATE
COLOADDREGISTRATIMMOSSI
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DISCOVERY FELLOWSHIP CHURCH
A portion of the Northeast Quarter of Section 13, Township 6 North, Range 69 West of
the 6th Principal Meridian, City of Fort Collins, County of Larimer, State of Colorado
OVERALL DRAINAGE AND EROSION CONTOL PLAN
C iYv F.TRL,C: NOTES
VEHICLE TRACKING CCNT IOU PAD
(Locic" APPROXIMATE. FINAL wixOt%i
TO BE DETERMINED BY CONWACTOR)
INSTALL SILT FENCE ALONG DOWNSTREAM Wp1TLf DINES (FY%
EAST TRILBY ROAD EA(TTENDINGAAMINIMUMO503PYOND
OPSTREMILIMITS OF CONTRUCTION. INSTALL IMET PROTECTION AROUND
_ IP EXISTING INLET N WEST F O MOF
NEB'IT 2YW .)e(Lp0' LEMAY AVE, IMMEDIATELY SCAUH OF TRILBY--- AMID. (INLET LOCATION IS BEYOND THE
-- SCOPE OF THIS DRAWING
10 0 L INSTALL BUT FENCE DIKE ACROSS FULL
1 hB
l
\ WIDTH OF CHANNEL, UPSTREAM OF EXISTING
y 1 DRIVEWAY CULVERT. ANCHOR SILT FENCE
_ _ A SECURELY IN FLOOR CE EXISTING
DEPR..�BYRASS
..A.... ... FLOW BENEATH SILT
TOENSURE
INTO URI
FLOW BENEATH 81LT FENCE MOCULVEM.
SEUMEM TRAP INSTALL SILT PENCE ME
UPSTNEAMCF WTLETCOMFKI
$TRUCTUflE IOTRAP SEGMENTS. SILT
FENCE IN MISN OWED ST 6XPLLST
SUPFORTEDONBRACEDSIEELPOSTS,NID
FLIERCREENNG FOR SUPPORT
ANWIRE
MESH SCREENING AN FORRIN OOD CON. MAINTAIN
DIKE IN PLACE PMSTRU CONDITION
MRWOHCUT IONHASICIION PERM AND
UMILVELISHED. REMOVE
BEEN
SEDIMENTS XED.PERDUE ACCUMULATED
SEDIMENTS PERKIDICPLLY, ASNECE&9MY.
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EXISTING PAVED--�
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LIMITS OF DRAINAGE BASIN
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SCALE. 1'= 40'-0" NORTH Knew rvhaPs 6elo%
—I-- Call before you trig.
0 20' 40 80' 120'
STANDARD GRADING AND EROSION AND SEDIMENT CONTROL CONSTRUCTION PLAN NOES
THE EROSION
CONTROL INSPECTOR MUST BE NOTIFIED AT LEAST
TWENTY-FOUR (24) HOURS
PRIOR TO
ANY CONSTRUCTON
ON
THIS
SITE
THERE SHALL
BE NO EARTH DISTURBING ACTIVITY OUTSIDE WE
LIMITS DESIGNATED ON ME
ACCEPTED
PLANS.
ALL REQUIRED PERIMETER SILT AND CONSTRUCTION FENCING SHALL BE INSTALLED PRIOR TO ANY LAND DISTURBING ACTIVITIES (STOCKPILING. STRIPPING,
GRADING, ETC.). ALL OTHER REWIRED EROSION CONTROL MEASURES SHALL BE INSTALLED AT THE APPROPRIATE TIME IN THE CONSTRUCTION
SEQUENCE AS INDICATED IN WE APPROVED PRWECT SCHEDULE. CONSTRUCTION PLANS. AND EROSION CONTROL REPORT.
AT ALL TIMES DURING CONSTRUCTION. THE DEVELOPER SHALL BE RESPONSIBLE FOR PREVENTING AND CONTROWNG ON -SITE EROSION INCLUDING
KEEPING WE PROPERTY SUFFICIENTLY WATERED SO AS TO MINIMIZE WIND BLOM SEDIMENT. WE DEVELOPER SHALL ALSO BE RESPONSIBLE FOR
INSTAWNG AND MAINTAINING ALL EROSION CONTROL FACILITIES SHOWN THEM.
PRE -DISTURBANCE VEGETATION SHALL BE PROTECTED AHD RETANED YMEREVER POSSIBLE. REMOVAL OR DISTURBANCE OF METING VEGETATION SHALL
BE UNITED TO WE AREAS) REQUIRED FOR IMMEDIATE CONSTRUCTION OPERATION, AND FOR THE SHORTEST PRACTICAL PERIOD OF TIME.
ALL SOILS EXPOSED DURING LAND DISTURBING ACTIVITY (STRIPPING, GRADING. UTILITY INSTALLATONS, STOCKPIUNC, FILLING. ETC.) SHALL BE KEPT IN A
ROUGHENED CONDITION BY RIPPING OR DISKING ALONG LAND CONTOURS UNTIL MULCH, VEGETATION, OR OTHER PERMANENT EROSION CONTROL. SMP'S
ARE INSTALLED. NO SOILS IN AREAS OUTSIDE PROJECT STREET RIGHTS -OF -WAY SHALL REMAIN EXPOSED BY LAND DISTURBING ACTIVITIES FOR MORE
THAN THIRTY (W) DAYS BEFORE REWIRED TEMPORARY OR PERMANENT EROSION CONTROL (E.G. SEED/MULCH, LANDSCAPING, ETC.) IS INSTALLED,
UNLESS OTHERWISE APPROVED BY WE CITY OF FORT COLLINS.
IN ORDER TO MINIMIZE EROSION POTENTAL. AIL TEMPORARY (STRUCTURN.) EROSION CONTROL MEASURES SHALL
A. BE INSPECTED AT A MINIMUM OF EVERY TWO (2) WEEKS AND AFTER EACH SIGNIFICANT STORM EVENT AND REPAIRED OR RECONSTRUCTED AS
NECESSARY IN ORDER TO ENSURE WE CONTINUED PERFORMANCE OF THEIR INTENDED FUNCTON.
B. REMAIN IN PLACE UNTIL SUCH TIME AS ALL WE SURROUNDING DISTURBED AREAS ARE SUFFICIENTLY STABILIZED AS DETERMINED BY THE
EROSION CONTROL INSPECTOR.
C. BE REMOVED AFTER WE STE HAS BEEN SUMCIENTLY STABILIZED AS DETERMINED BY THE EROSION CONTROL INSPECTOR.
WHEN TEMPORARY EROSION CONTROL MEASURES ARE REMOVED, THE DEVELOPER SHALL BE RESPONSIBLE FOR THE CLEAN UP AND REMOVAL OF ALL
SEDIMENT AND DEBRIS FROM ALL DRAINAGE INFRASTRUCTURE AND OTHER PUBLIC FACILITIES.
THE CONTRACTOR SHALL CLEAN UP ANY INADVERTENT DEPOSTED MATERIAL IMMEDIATELY AND MAKE SURE STREETS ARE FREE OF ALL MATERIALS BY
THE END OF EACH WORKING DAY,
ALL RETAINED SEDIMENTS. PARTICULARLY THOSE ON PAVED ROADWAY SURFACES, SHALL BE REMOVED AND DISPOSED OF IN A MANNER AND LOCATION
SO AS NOT TO CAUSE THEIR RELEASE INTO ANY WATERS OF THE UNITED STATES
NO SOIL STOCKPILE SHALL EXCEED TEN (10 FEET IN HEIGHT. ALL SOIL STOCKPILES SHALL BE PROTECTED FROM SEDIMENT TRANSPORT BY SURFACE
ROUGHENING. WATERING, AND PERIMETER SILT FENCING. ANY SOIL STOCKPILE REMAINING AFTER THIRTY (30) DAYS SHALL BE SEEDED AND MULCHED.
THE STONMWAMR VOLUME CAPACITY OF DETENTION PONDS WILL BE RESTORED AND STORM SEWER LINES WILL BE CLEANED UPON COMPLETON OF WE
PROJECT.
OTY ORDINANCE AND COLORADO DISCHARGE PERMIT SYSTEM (CUPS) REQUIREMENTS MAKE IT UNLAWFUL TO DISCHARGE OR ALLOW THE DISCHARGE OF
ANY POLLUTANT OR CONTAMINATED WATER FROM CONSTRUCTION SIZES. POLLUTANTS INCLUDE, BUT ARE NOT LIMITED TO DISCARDED BUILDINGS
MATERIALS. CONCRETE TRUCK WASHOUT. CHEMICALS, OIL AND GAS PRODUCTS. LITTER, AND SANITARY WASTE. THE DEVELOPER SHALL AT ALL TIMES
TAKE WHATEVER MEASURES ARE NECESSARY TO ASSURE THE PROPER CONTAINMENT AND DISPOSAL OF POLLUTANTS ON THE SITE IN ACCORDANCE WITH
ANY AND ALL APPLICABLE LOCAL, STATE AND FEDERAL REGULATIONS.
A DESIGNATED AREA SHALL BE PROVIDED ON SIT FOR CONCRETE TRUCK CHUTE WASHOUT. WE AREA SHALL BE CONSTRUCTED SO AS TO CONTAIN
WASHOUT MATERIAL AND LOCATED AT LEAST RRY (SO) FEET AWAY FROM ANY WATERWAY DURING CONSTRUCTION, UPON COMPLETION OF
CONSTRUCTION ACTIVITIES WE CONCRETE WASHOUT MATERIAL MILL BE REMOVED AND PROPERLY DISPOSED OF PRIOR TO THE AREA BEING RESTORED.
CONDITIONS IN THE REM MAY WARRANT EROE ON Col MEASURES IN ADDITION TO WHAT IS SHOWN GN THESE PLANS. THE DEVELOPER SHALL
IMPLEMENT WHATEVER MEASURES ARE DETERMINED NECESSARY, AS DIRECTED BY THE CITY OF FORT COLLINS.
A VEHICLE TRACKING CONTROL PAD SHALL BE INSTALLED MEN NEEDED FOR CONSTRUCTION EQUIPMENT, INCLUDING BUT NOT LIMITED TO PERSONAL
VEHICLES E%I LNG EASING ROADWAYS, NO EARTHEN MATERIALS, I.E. STONE. DIRT, ETC. SHALL BE PLACED IN WE CURB AND GUTTER OR ROADWAY AS
A RAMP TO ACCESS TEMPORARY STOCKPILES, STAGING AREAS, CONSTRUCTION MATERIALS, CONCRETE WASHOUT AREAS, AND/OR BUILDING SIZES.
THE CONTRACTOR SHALL ALSO REFER TO THE APPROVED STORMWAMIR MANAGEMENT PLAN AND EROSION CONTROL PLAN FOR ACTONS TO BE TAKEN
DURING CONSTRUCTION TO UNIT EROSION AND MINIMIZE WE RISK OF OFF -SITE TRANSPORT OF SEDIMENTS AND OTHER POTENTALLY HARMFUL
MATERIALS
BMIF SEQUENCING CHART
MOMllatlon
Ftlm blxYn SiMGmdiM I'VerhalComitl
FleBeerbinW. I
Landiscatil"111 Demobilization
Beg Mane menlPMotlwe SM
S1,UCIUmil "IretaIlBMi
Silt FIAI
Vlncle Tlecki Pea
Inlet PMeiVan lAn e,ristinG inlets ay.Ynatltelll NaBe
SeaimMR TW / Filter (in MCMicn Bmin) Ses rcb / aps BLVIe
Contw Flamts (HIM / DII Ses Emei6n CmlM ReDol
WaUle Dkes
RIOSPAImaMO
•All BMPb ere to Oa mmesi mrtce Cartavive n is compete
V e
TNnwary SEEKIN / Pumal
MUICNrp Swiss/ SM
Am time the site Will At dermeN kxXW Nan GO Rye.
AM time iDo site Will SitaminMm krGW man 300P/s.
PermWm[Smairq/
RMICAI PMaucts I BMIW,%s I MEN)Useen
a e10Pes, as IIN-eeu I%NI a steNlaNad.
APPROVAL SIGNATURES
ALL CONSTRUCTION SHALL BE IN ACCORDANCE WITH ME CITY OF FORT
COLLINS STORMWAMRCRRERIAMM'UAL. CITYACCEPTANCESIMLL
NOT RELIEVE THE DESIGN ENGINEER OF RESPONSIBILITY FOR ERRORS.
OMISSIONS OR DESIGN DEFICIENCIES, FOR WHICH THE CITY IS HELD
HARMLESS.
LT7SUP(y I
CHECKED BY
CHECKED BY
CHECKED BY
CHECKED BY
CHECKED BY
City of Fort Collins, Colorado
UTILITY PLAN APPROVAL
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DISCOVERY FELLOWSHIP CHURCH
A portion of the Northeast Quarter of Section 13, Township 6 North, Range 69 West of
the 6th Principal Meridian, City of Fort Collins, County of Larinner, State of Colorado
SITE GRADING & DRAINAGE IMPROVEMENTS
EXISTING m'pA. XOPENIDRAIN
189.7LF..]LF.®3B3%
EAST
TRILBY
ROAD
MISTING STORM
RIM RM MA HOLE
ELEV-01
INV.II-A5217
IW OUT(EI-49I
EXISTING PAVING PLANTING AREA
n
EXISTING W CIA. HOPE W12 STORM DRAM
(LENGTH B GRADIENT UiDEIERMNEO)
EMERGENCYSPILLWAYSILL (WE DETAIL)
BOUNDARY OF REVISED DRAINAGE
EASEMENT
D r-v
♦♦�1 y I ♦♦�`♦♦
♦♦♦ `\� `IIII I \\` \M
% HIM
l 1 1 1
1
1 1\ j I111
III 111 ,1 I I 11,1
1 1
\ TO Is- -4M5.5 IIII IIIIII 1 CANCREIEI II IIII \1\I1
\8.0 W. M.-49413IN 11 ARw �PATp
T.O.W. EL. •491 II
B.O.W. EL. •4W.3
'TOW.EU-4939.5 IN;
\� IN ```\♦\ NARY ER080N I`\
COMEGUATE SUCK \\
` `-PROP08EOYWTI WNG ••�```•\REVEGERTHANL1
EXPANSION -. ♦ \I`\. \ITYEa�)THANA:1 �\ \ 11
II _
E%ISTING SANCRW2Y � e__ _
EXISTING CHURCH j
OFRCES&NORSEM`
FF.E-491e.5N- ^ I I
E
EXISTINGSTORMMANHOLE
RIM EL -MiQ63
INV. IN(AM -4032
INV. OUT (BE)=4923.1
MISEMANHOLEAS
NECESSARY TO SUIT NEW
DETENTION BASIN
EMBANKMENT ELEVATION.
EXISTING 24 CIA HOPE N1.
45LF. 03.5%
i
Know whatis below.
Call before you dig.
T.O.W. EL. =4900
Z U
S.O.W. EL.•49M5
TOW EL.•49A4
J
E
B.O.W. EL .• AIDES
{
PLACE TYPE"M" RIPMP ARMORING THROUGHOUT
ZN-
(1
FULL EXTENT OF EXPOSED SUMP ARM ARMDRING
Lill z
TO EXTEND UP TO ELEVATION 49H 0
INSTALL INTERLOCKING BLOCK HEADWALL TO RETAIN
Q ,�p
OVv
e
ap
T.O.W. EL.•A92).0
EMBANKMENT FILL. TOP OF WALL ELEVATION-492T.0
;
81
B.O.W. BL.-49216
ggg
e
EXISTING 24" OM. RCP CULVERT W F.ES.
f
T.O.W E. =492)0
BENEATH APARTMENT COMPLM DRIVEWAY
6666
B.O.W. EL. -49242
DISCHARGING TO OPEN CHANNEL EASTF.
RO
TO.W. EL.=49A.4
B O.W. EL. • 49250
MISTING 3P DM RCP PIPE BENEATH
APARTMENT COMPLEX DRIVEWAY
DISCHARGING TO OPEN CHANNEL EAST
EXISTING STORM MANHOE
�N
RIM ELEV.•49P.0
EXPOSE AND SALVAGE EXISTING IS"OIA HOPE STORM
IW. INN-4922.0
? Q
r
GRAIN BETWEEN EXISTING MANHOLE AND CUT LOCATION
ROM IN(S)=4924.0INN,
v
ATSE CORNER OF DETENTION SASIN. RELAYAFPROX.
OUT (E) • 4921E
13 OF EXISTING PIPE 00.80% SLOPE, INCLUDING IEW
RAISE MANHOLE LID. RIM AND COVER AFPROX 3.0 FT
a
I
1VDIP. 90 DEG. BEND, TO SERVE AS DISCHARGE PIK
TO SUIT OETENTICN BASIN EMBANKMENT FILL
FROM OUTLET CONTROL STRUCTURE, AND RECONNEW
TO MISTING MANHOLE INLET.
IN 0
PIPE INVERT AT OUTLET CONTROL STRUCTURE -492413
p
PIPE INVERT AT MANHOLE = 49240
!2 Q
2 CONCRETE TRICIGE PAN
INSTALL TYPE -L-RIPMP ARMORING G50 • B9
IN AREA SHOWN SINGED TO PREVIEW EROSION.
RIPRAP SHALL BE BURIED BENEATH B OF TOPSOIL,
SEEDED NTH NATIVE GRASSESAND MULCHED TO Z
1` PROTECT SEED UNTIL GERMINATION. C
CUT EXISTING IF DIA. HOPE STORM GRAIN AT THE Imo.
ROM THAT IT INTERSECTS DETENTION BASIN e
SLOPE (APPROX. INV. ELEV. JIM 0) AND INSTALL
NEW FEE REMOVE EXISTING DOWNSTREAM Mxi
AI PIPING FROM THIS POINT TO THE MANHOLE, AND
IIt PIPE INVERT AT OUTLET CONTROL STRUCTURE V
481.13 PIPE INVERT AT MANHOLE :411
!p� O
DRAINAGE I DETENTION SUMMARY
m U
DNlne sBasin Area(Including ofil tributary area
ac
5Al2
Composts RunOTI Coef3c'Mnt
0.40
30.43
.Porwntlmpowiomm
Design Shan Runoff
(Oft)
- 2-yr Storm Event (Oil
4.24
100-yr Storm Event (Qm@
19.39
Allowable Release Rate
eh
7.152
Required Detenbon Cape*
(ealq
• WOCV
0.088
• 100.yr Stone Attenuation
0.233
- Total
0.319
Detention Water Surface Elevation
(it)
- VII
4928.55
100 yr Storm Attenuation 4 WOCV
4928.96
NIIII
%INNNNN
FUTURE ONCRAPRON
`SLOPEAWY
OM ILDIN. GAT t%
O
i
NOMINMLELEVATION=4ws
APPROVAL SIGNATUPES
VUi
EXISTING IV HOPE W,: STORM DRAIN
S'
O
i
1I\
218.4 LF.®338%
ALL CONSTRUCTION SHALL BE IN ACCORDANCE NTH THE CITY OF FORT
I
COLLINS STORMWATER CRITERIA MANUAL. CITY ACCEPTANCE SHALL
I
1\\Vi
BOUNDARY OF EXISTING DRAINAGE
NOT REUEVE THE DESIGN ENGINEER OF RESPONSIBILITY FOR ERRORS,
EASEMENr.
OMISVONSORDESIONCEFICIENCIES, FORWHICHTHECITYISHEID
HARMLESS.
r
j,
EXISTINGSTORMMANHOM
RM EL. -MI
City of Fort Collins, Colorado
INV. IN (WJ =492t3
UTILITY PLAN APPROVAL
1
INV. OM(N-A9311
EXISTINGIVDM. HDPENI2STBRMDMIN
139.41.F1834%
APPROVED:
SEC11pNCFMISTINGSIDEWALX(APPROX
Ctr EIplrwer Dxe
TO BE REMOVED, AND NEWSIOEWALK
TO BE CONBTRUCTEO IN CONULMCTION
CHECKED BY'.
k
MATH SANCTUARY EXPANSION
Wex4 Walewerer WlRy pMF
CHECKED BYStmrweler
UII1TY DMF
F157)
CHECKED BY:
tCHECKED
BY:iTraMcErOirow
DW
1
SCALE: 1'�$Y-0' NORTH
16NOV12
CHECKED BY:
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0 19 29 40 89
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1I
DISCOVERY FELLOWSHIP CHURCH
A portion of the Northeast Quarter of Section 13, Township 6 North, Range 69 West of
the 6th Principal Meridian, City of Fort Collins, County of Larimer, State of Colorado
DRAINAGE & DETENTION DETAILS
AN
OPRGNN CONC6EIE "Iova (m) STEEL CN4iML FORMED
I�NDD PAD (FNO of PAD TOwTa N10 @EIE ICRSIDES
- BD of MIND MACE) I WTI
IlA 3'-6'
6' TRAGN P/CK 3/n151ED NCRJ55 I
i/4' PULE, wF1DED 511d1' EU ROUND O
To CHNTE MIH T
(3P 6 CR05 DHc l l
3/8•A6• THREADED SOLT
CT FASTEN CRAZE DOD! \ BARS AT 3' O.C.,
(IYP. OFF. SIDE)'""�\ &IRS A TO O.C.. " I I
\ 2 1/2' BC.) AT I I
� 2 1/Y D.C.)
M
IF
I�
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mmnununnm:
onnnnunnnn
QII
nsub,amuununnnu
nY
WRENN■
oil
MAP.
�
�nunumm�nnE
Ynunv-.unmlm
n■aIltl■■■■■i■■■■■■■Y
nn
lnnnn
1 / I `UFAS MEN EN1N L
J//CONa OPENING
YIEIL SCREEN N0. 93 (FASTEN Y4M J/B'K6'
TREADED BOL15)
(U.S. RLTFF srNNIES9 A B PLAN D /�3//9.1,5• BOLTS 1z•
SIFFL OR ET7UN) / lb HOLD HLIKE IN
1/A• FMW rr l
WELL
(M
ME
CITY OF
1/4• PLATE, HDDED TRASH RICK
TD CRATE 111111 (NOTE 5) —
3 B48' TNREADIED BOLT
FASTEN GRATE DOWN 1
OUTLET
40R3
T
SECTION C-C
DETAILS
12-316" DR. ORIFICE (IOCII STORM)
CUT OUT CENTRAL 1-AT BOTTOM
OF ORIFICE TO ALLOW COMPLETE
DRAINAGE OF OUTLET
STRUCTURE.
-,�1•.'- BOTTOM EDGE OF ORIFICE PLATE
TO BE SET FLUSH WITH FLOOR OF OUTLET
CONTROLBOX
100-YR ORIFICE DETAIL
SCALE:NTS
DI
•lee
.l.
•le
less
le se
le a el
I• 0 •I
'YAW
HOLE (RPa• Sli
�TABLE
`5 EEL FLOW CONIRO
PLATE
TM STEEL ANCHOR BOLTS OR BODONI POw OF 3• (7yp,) `SINNLESS STEEL
wE1D5 ON TOP NO SOB IIOE$ 10 ff AT NICHDR BOLT
INAU T OF PLATE
WELL SCREEN FLOW CONTROL PLATE
SECTION A -A SECTION B-B
SECTION D-D
+41112• DOW PIPE
—i4012'
GENERAL NOTES
1. QHCRETE 9111 BE CUSS B. WY BE VST-N-R/CE OR PRSUS.
2. RENFORUNG BIRS PWL B1 EPOV ONTO AND aTgi , MO 9wl
W\K A WMA1 Y CIfMNVCE
3 1/2•
3. STEPS SML BE PROVIDED MIN VERIMN OMISSION EACUDS X-6'
3' CUP
'� SHRI MIN NYCIDVICE Nm hiw M Isar.
K1 I/2•
KEY
4. ALL SAW FACKS SHALL BE MDAIID) USING VAN ESC STEEL HAACwAIE MD
_
PROVED) WIN IwDED AND LOCRYAL OR BOUT.AFI£ AD ESS PAMIS
5. TFA91 WAS SHALL BE AN1LE55 STEEL AWMNW, OR SKEL STEEL TWSN
RACKS LPll SE HOT aP U1V,Wtm ND WY M NIT NAaA PNXIED
21'—%
1.1?
O O W16'THICKHOT-DIPPED
GALVANVED STEEL
PLATE
K'a BORE OF 15- CIA. DISCHARGE PIPE BEYOND
12J CIA. ORIFICE (SEE DETAIL BELOW)
O\
)V DIA. ANCHOR BOLT HOLE
(4 REOD)
FORW DH0. EXPANSION
BOLT.
IRO-YR STORM ATTENUATION ORIFICE PLATE
$GALE: NTS
LEGEND
A A
SECT)ON LNE A -A WM
SECTION
INDREawR
ABBREVIATIONS
CLA. af/PMlF
TYP, iTPKN
DML OYIDFN
No NOM a' COIDNTE a
ETEV. E11WllON
VIP w OF RATE
NV. NARI
NO MNR O
MAN. 1MaRIlY
V IDlGM m STRUaLBE
MIN. MWiIN
we 1DM a SMDREE
O.C. ON FDnu
/ NBMER
OPP. OPIDNIE
a At
BEEN.
A POND TIN.
4924.33
SUN
S
4926.55
M.
C
4927.55
SRI
M.
4928.96
Dom
12• 111
2.22
V
VAT
w
eu'
HOLE BIL
0.5'
WO
I f OF ROWS
7
Ff R COYHS
1
OEFEMION &151NCRFST
(HEV.4930.OR
av
Zara
� A
n H
-J'CLR (1YP)
SILL ELEVATION
SCALE:1 =1vY
EMERGENCY SPILLWAY SILL
SLOPE VARIES p SLOPE VARIES
CONCRETE
SECTION
TRICKLE PAN
SCALE: NTS
TOP SOL a SURFACE
VEGETANON
TYPE -L' RIPRAP (TYP)
8 OZ/SY NON-INOWN
GEOTEXTR-E FILTER FABRIC
REINFORCED CONCRETE SILL
(SEE DETAIL THIS SHEET)
EMERGENCY SPILLWAY SILL - ENLARGEMENT
J SCALE:NTS
APPROVAL SIGNATURES
ALL CONSTRUCTION SHALL BE IN ACCORDANCE WTH THE CITY OF FORT
COWNS STORMWATER CRITERIA MANUAL. CITY ACCEPTANCE SHALL NOT
RELIEVE THE DESIGN ENGINEER OF RBSPONSIBIU YFOR Boat iB
TOP OF SRLLYMYSLL OMISSIONS OR DESIGN DEFICIENCIES, FOR VMICH THE Clry IS HELD
ELEV. 4NNW HARMLESS
3'
M B4R CGMIHOUS1g REED )
NDctB'BAR®a-o'G
SINGLE OURNN n g•
SILL SECTION
SCALE: 1--2-P
City of Fort Collins, Colorado
UTILITY PLAN APPROVAL
APPROVED'
Cm/Englrwer Dow
CHECKED BY: _
vAmavme..wr uWlry Dew
CHECKED BY:
Srormxwer UYfry Dq4
CHECKED BY:
Parke a Rxreetion DFw
CHECKED BY'.
TrNSC Engineer pM
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Zyn
fi
WZO
30 OU0
el.
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$GALE: NT$
CHECKED BY:
Dare
n
AVERSION RIDGE REWrREO
WRERE GRADE EXCEEDS 1F 2 F OR CRGICR
ROADWr
AL III FAMRIC
SELTON A - A
\
Ati>F /
Go CO BILE$ SINGGGO sPKLXNr OR espy AVI NEED
AR CdIr NrILBERM G TO ONIER APPRISED
FIXNVfLENr HCMHr rD CHAS AVOE RONOfF 0eAm+As REWIRED
Sheary WIFA r0 WEN
wHats IF nrcEssA.w `(x/ _
AGGREGAI 12' Will
23
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0 L_
nBa _1J � rmw
MN or 050l TH2x' CI )
�OnERnI+..'ccs ,
50'(15m) MN -- -�
PUPA
NORM'
I we EN is"NEF SWLL BE WIMNNED N i COMarOV RAT WILL PRFKM
MORN GSEDIMENT Ovrp PUBLIC RIGHT-DF-WAIS. MIS NAY
R
Ar l TOP TOP ORS0.4EISSINGREPAIR AWDIT LLGM NOOF ANY RGSURES USED
szo
2 WHEN NELESGRY, XYIEELS Shl BE
CLEWED PRIOR lD EMPANCE ONTO FLul
Rup
R.GWr-w-WAX TEMPORARY
S J. WHEN WASHING lS REWIRED. Ir SIALL M GRAVEL
i sSIOME c r D,w"°E"LFrs INTO AENDAroRMED HGO CONSTRUCTION
SEXUrNr MAP DR SEDIMEM BASIN. ENTRANCE EXIT
O
BILK r SrOEWALK
BACK OF GARB
AKDO $IW
Oul BLOCK
JSR/C \ L A-LONLRETC BLOCK
314- a DRVN GAS Kt J PLAN VIEW
(zol
PONDAG NEON,
�IEREZON CONCRETE BLOGw
CURS Auer. -PARE SCREEN Go
EIL IER FASRIL GILN BISIN
NO1£S I I
I. LSE SLOLK NIP GRAVEL TYPE SEDIMENT
BARREN WHEN CURB INLET IS LOCATED /N
yEO A - A
CENILY SLONNC STREET SESMENT. WHERE
Al (AN F9N0 AND ALLOW SEDIMENT TO
SEYMRAR'FROM RUNOFF
2. BARRIER ERMI ALLOW FOR OKHFYDW
FROM SEVERE STORM EYFM
Aa**fin
CURB
J INSPECT BARRIERS AND REMOIT SFO/MFM
SEDIMENT
AL/ER EACH Smell EVENT SEDIMENT AND
GkIltrt MUST BE FAOM ME
RUNLED WAY /MMFD/ llEY
IBLOC.E B
DISCOVERY FELLOWSHIP CHURCH
A portion of the Northeast Quarter of Section 13, Township 6 North, Range 69 West of
the 6th Principal Meridian, City of Fort Collins, County of Larimer, State of Colorado
EROSION CONTROL DETAILS
TEMPORARY GRAVEL CONSTRUCTION ENTRANCE/EXIT
Construction Specifications:
The aggregate size for constmction of the pad Shall be 2-3 men (51-76
mm) stone. Place the growl to tre specific grade and dimensions shown
n the plans, and smooth it.
The thickness of the pad shall not be leas than 6 inches (0.2 an). I
geotextge fabrics, if necessary, to improve stability of the foundation in
locations Subject to seepage or Sign water table.
The width of the pad shall not be less than the full width of all points of
ingress or egress and in any caw shall not be less than 12 feel (3.6 m)
wide.
The length of the oo shall be an uired but not Ives than 0 feet
fig p required. 5 e
Loco ).
Locate construction r entrances tine exits to limit sediment leavingthe site
and to o f steep
m d II A Quid or ma utility D a construction wM1idss. witl
provide u Y Y
entrances which have steep 9nd<a and entrances at curvesIn public roads.
One entrance shall be mprevent in a condition that will prevent tracking
Periodic
of sediment auto public righter -off -way. easc ions de require.n
9 PY
repair
and/or lap ma int anh aof crypt sasue tie sed toot a demand, anti
epair ntmaid, drops of any measures tracked
to trap wdimml.
All sediment spilled, dropped, washed or lracketl onto public rights -of -way
anal be removed Immediately.
Provide drainage to carry water to a wdiment trap
se other suitable outlet.
WTw ceConto J, public
rights -of -way.
shallf- all n remove is sediment prior h
to
entrance onto public rights -with way. Wren washing II required, It Shall be
done en an r area stabilized with crushed atone that drains into an approved
Sediment sedi hop al sediment basin.
All sediment shall be use
ofsprevented from entering any atarto emir, then or
watercourse shads. uw of vend bags. growl. straw pales, or other
approved meth Ma.
naintoin and Maintenance:
Maintain the gravel pad in a candifoT to prevent ^.ud o• wdiment from
leaving the constructionsite.
lace Repgrowmaterial
l materialal when surface voids Hsbe.
After each rainfall, inspect any structure Decoed to tap sediment and dean
IImmediately
t a9 nwemove
public
remove al' Remove all s materials posse. washed, or tracked
onto public roadways. Remove all sediment cepoaited on paves roodwaya
within 24 awn.
Place the barriers w gently eloping streets where water can pond.
The barriers must allow for overflow from a wevere storm event. Slope
runoff shall be allowed to flow over blocks and growl arc not be bypassed
over the curb. A spillway shall be constructed with the sandbag structures
to allow overflow.
The sandbag should be of woven -type geatexille fabric since burlap bogs
deteriorate nor ly.
The scrol ga shall be filled with 3/4 inch (19 rum) drain rook or inch
T6 rum) pec growl.
he sandbags shall be placed in a curved row from the top of curb at Twat
3 feet (0.9 m) into the street. The row Should be curved at the ends,
painting uphill.
Several layers of bags shou d be overlapped and packed tightly.
Leave a we-shi gap In the lop row to act as a spillway.
For Block and Gravel Type Barriers:
Place two concrete blocks on their sides perpendicular to the curb at either
end of the inlet opening. Thew will serve as spacer blocks.
Place concrete blocks an their sides across the front of the inlet and
abutting the spacer blocks. The openings in the blocks should lace
outward, not upward.
Cut a 2 by 4 inch (51 by 102 mm) stud the length of the cum inlet plus
the width of the two spacer blocks. Place the stud lhrOLgh the outer hole
of each Spacer block to help keep tre front blocks in place.
Place wire mesa over the outside vertical face (open ends) of the concrete
blocks to prevent stone from being washed through the blocks.
Use chicken wire. hardware cloth wil 1/2 inch (13 rum) opeings, or flew
fabric.
Place 3/4 -1 1/3 Inch (19-34 mm) growl against he wire to the top of
the barrier.
Inspection
and Mo'ntenonce:
and door
and
remove sediment fromer behindnsandbagfter each structure soften ceveery tstorand
Any sediment and growl shall be immediately removed from the traveled
way of reads.
The removed sedimert Shall be placed where it conrot enter a storm drain,
stream, ar be transported off site.
If the growl becomes clogged with sediment, it must be carefully removed
tram the inlet and either cleared or replaced.
EXIRA SIRENCM ik2R FAd
NEEDED AN/NOW WAer' MESH
51FFL
NOW
IBNAfSfTu SPACING W/M
b' II= SWINUM SPACING w9R/DUI
SWPoRT QhCE
�SIEEL OR NODO POST
J6- (Im) H/L// MAX
9VOlNC HEIGHT OW(ISO
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iAEACN xrm fW
TRENCH all INRMIAOXIN WRIWR TREN ice
AVAES
I. Der LIGNI sil EE HACED ON Stone
0000aphS w NUNIIE RbIWrK. ESNCIENCr.
hDI 10 SGLE
2 MSPELr ANP Ali LEA? ArrER DART
SIDMI EYEM A,e REMOK SELNMENr MNSN
AYLIRSAW 9 2PS. MWIMUV
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SILT FI
SEDIMENT OFF -Sur AND Lw � FERMANSWAr
SIAEW.I2ED.
SILT FENCE
Construction Specifications:
The height of a sill fence Shall not eed 36 inches (0.9 m). Storage
height and pording height shall news, exceed iB inches (0.5 m).
The fence line shall follow the contou as closely as possible.
If possible, the filler fabric Shall be C it from a continuous roll to avoid the
of pints. When joints a y. filter cloth Shall be spliced only at
support Pont, with a minimum 6 In In (0.2 m) overlap and both ends
securely festered to the post.
Posts sholl be spaced a maximum of 10 feet (3.1 m) apart and driven
securely Into the ground minimum o 12 inches a.3 m Wren
extra -strength fabric is used without Ma wire Support fence, post spacing
shall not exceed s teat fence
m).
A trench
the shell of ex fence u hill.
P
A trench anal) be excavated o line
o let 4 Inches 101 fr voice and 6
PP Y ( m)
Man tang rd deep along the line of Dosed, and wire
ham the barrier.
Wren Do
alter lckhe u is used, c f t mean support fence
snarl wine
fastened tleasto the u. a mm) long.
of the posts using rwv
securely oelop p 1 9 Y
They wiro hall ea it limo tincn (25. rum) long, lie wires or hog rings.
The wire shill extend into thetrench a minimum of 2 inches nrum) one
shall not extend more than 36 inche (0.9 m) above the original ground
surface.
The nstrength filter /Dark sh II be stapled or wired to the fence,
6i
and 6 inches
m) of the fabrics ill extend into the trench. The
obnc shin nott extend more than 36 Inches (0.9 m) above the original
ground surface. filter fabric shall rod be elapsed existing trees.
When extra -strength fabric and loser Post spacing are w6 the wire
mash support lance may
be he post '�n such a case, the filler fabric is
sta'Ire trench
c wired dirbe bay to the poste
Te trench Shall be backfilletl and ON soil compacted over the toe of the
filler fabric.
SN fences placed at the toe of a slips shall vo set at least 6 feat (1.8
Slit from me toe in removed
to hen is pending volume.
Silt fences shall be removed when th+y how pservedermanently
their useful
yne Pend cr
but not before Me ndl the or" hap been permanently n:aDilixed and any
sediment stored ainter me Gilt force has been removed.
Slit
forces
and Maintenance:
Big fences and filar barriers anal) be inspected hour weekly alter each
Do made storm (I inch (25.4 mmJ 24 hour). Any required repairs Shall
tie. ishon err.
rices Sediment 3 an) a emovetl wow R 400<nea 1/3 height of the fence or 9
Ther move m) maximum.
The removed sediment shall conform with the existing grade and be
willwillor otherwise atatobilized.
WATTLE DIKE NOTES --
A. Single slakes shou at be driven through the
middle of the wattle. LeWWWWWWe 2 - 3 inches of
the stoke protruding abo the wattle. A
heavy sediment load will t ntl to pick the
wattle up and could pull off the stakes R
they are driven dawn too 110 . It may be
necessary to make o hole in the wattle with a
pick in order to get the I ake through the
straw. Wher strow wattle are used for flat
ground applications, drive he slakes straight
been; when .retailing watts on slopes, tlrive
the stakes perpendicular t the slope.
B. Double stokes should be c iven ounces from
Such other and on each i do of the wattle.
Slowing 4r-6• of slake of, ruding above the
watt e. boiling wire or ny n rope should be
tied to the stokes across he attle. stakes
should then be driven untl the boiling wire or
nylon rope is sufficiently snug to the wattle,
APPROVAL SIGNATURES
ALL CONSTRUCTION ShALL BE IN ACCORDANCE WITH THE CITY OF FORT
COW NS STORMWATER CRITERIA WINULL. CITY ACCEPTANCE SHALL NOT
RELIEVE THE DESIGN ENGINEER OF RESPONSISIUm' FOR ERRORS,
OMISSIONS OR DESIGN DEFICIENCIES, FOR WHICHTHE CITY IS HELD
City of Fort Collins, Colorado
UTILITY PLAN APPROVAL
City Engineer qb
Water a wasrewakir ueoy Does
Psdua Reurnmon Din
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