HomeMy WebLinkAboutMASON STREET SUSTAINABLE DEVELOPMENT - FDP - FDP140020 - SUBMITTAL DOCUMENTS - ROUND 1 - DRAINAGE REPORT1501 Academy Ct. Ste. 203 Fort Collins, Colorado 80524 (970) 530-4044
Final Drainage Summary S
401 South Mason Street
FortCollins Fort Collins, , CO
Prepared for:
Coin Street Mason, LLC.
5425 Tradewind Drive
Windsor, CO 80528
July 2, 2014
Drainage Summary
401 South Mason Street
Fort Collins, CO
1 U13008-DrainageSummary-Final.doc
July 2, 2014
City of Fort Collins
Stormwater Utility
700 Wood Street
Fort Collins, Colorado 80521
RE: 401 South Mason Street
Fort Collins, Colorado
Project Number: U13008
Dear Staff:
United Civil Design Group, LLC. is pleased to submit this Final Drainage Summary for the 401
South Mason Street site in Fort Collins, Colorado. In general, this summary serves to document
the stormwater impacts associated with the proposed 401 South Mason Street project.
Site Location and Project Description
The development site (referred herein as ”the site”) is located at 401 South Mason Street in
the City of Fort Collins, Colorado. The site consists of approximately 2,830 square-feet (sf) and
is bounded by Magnolia Street on the north, Mason Street on the East, an existing restaurant
on the south, and a residential property to the west. See the attached Drainage Exhibit for
additional information.
The planned development for the site will consist of the following:
• The removal of the existing one-story building and parking areas on the site.
• The construction of multi-story, mixed-use building with a proposed footprint of
approximately 2,530 sf.
• The construction of utilities to support the proposed building including sanitary, water
and storm drainage.
• The construction of right-of-way improvements including curb and gutter, public
sidewalk and landscaping.
Drainage Summary
401 South Mason Street
Fort Collins, CO
2 U13008-DrainageSummary-Final.doc
Existing Conditions
Hydrology
The site (Basin A1), which is located within the Old Town Basin, currently consists of an
existing one-story building, parking area, and a small landscape area with an existing
percent-imperviousness of approximately 88%. Storm runoff from the site currently
drains towards Magnolia and Mason Streets where runoff is intercepted by existing
storm sewer inlets and piping located within Mason Street. Refer to Appendix A for
additional information.
Floodplain
The site is located within the City-regulatory Old Town Basin 100-year floodway, flood
fringe, and moderate risk flood fringe. The Old Town Master Plan was approved July
15, 2003. The site is not located within a FEMA floodplain or floodway. Refer to
Appendix C for the Drainage Exhibit and FEMA FIRM panel.
Developed Conditions
Hydrology
The developed site of 2,830 sf will be entirely covered by the proposed building
footprint. The rooftop is currently being proposed to provide approximately 970 sf of
green roof which results in a proposed percent-imperviousness for the site (Basin A1) of
approximately 60%. Existing drainage patterns are being preserved with the proposed
development and water from the site will be directed from the rooftop to the existing
storm sewer system located with Mason Street. Refer to Appendix A for additional
information.
Floodplain
The site is located within the City-regulatory Old Town Basin 100-year floodway, flood
fringe, and moderate risk flood fringe. The following design elements are being
proposed with the development:
• The proposed non-residential building (having no residential component) will be
located outside of the floodway and is more specifically located approximately
6-feet south and 4.5-feet west of the floodway boundaries.
• The development team is currently proposing to flood proof the proposed
building in lieu of raising the finished floor 18-inches above the Base Flood
Elevation (BFE). Refer to the Drainage Exhibit and architectural plans for
additional information regarding the building flood proof design.
• The building construction will include a basement with concrete caisson
foundations. Refer to the Drainage Exhibit for a typical cross section detail of
the footing design.
Drainage Summary
401 South Mason Street
Fort Collins, CO
3 U13008-DrainageSummary-Final.doc
• Improvements being made within the floodway are design to existing grades
with the intention that they shall be constructed at or within 0.04-feet of
existing grades.
The following requirements shall be met regarding the design and construction of the
proposed mixed-use building:
• All flood proofing measures shall adhere to Section 10-38 of the City Code and
the requirements set forth within the City’s “Floodproofing Guidelines”. A Post-
Construction Flood Proofing Certificate will be required prior to the issuance of a
certificate of occupancy.
• All development within the city regulatory floodplain must be preceded by an
approved floodplain use permit and applicable fees.
• All development within the city regulatory floodway must be preceded by an
approved no-rise certification followed by re-certification of no-rise in the as-
built condition.
• A flood proofing certificate will be required prior to the issuance of a certificate
of occupancy.
The following table summarizes the floodproofing elevation requirements to be met
during construction:
Description Elevation
(NAVD-88)
City Base Flood Elevation (BFE)* 4996.93
Regulatory Flood Protection Elevation (RFPE) 4998.43
Lowest Floor Elevation 4985.50
Flood Proofing Elevation 4998.50
HVAC Equipment Elevation (In Floodproofed Basement) 4985.50
*Information provided in the above table is based upon the
interpolated BFE located at the northwest corner of the proposed
building.
Detention Requirements
Per communication with City personnel, the site has historically paid fees for 100%
imperviousness. As the existing site currently has an approximate imperviousness of
approximately 88%, City personnel have approved a variance to waive the detention
requirement for the site
Water Quality Requirements
The site is located within the Udall Natural Area which provides water quality for the
site; and therefore, additional water quality is not required. However, the development
is currently proposing to provide approximately 970 sf of green roof which will provide
additional water quality for the site.
Drainage Summary
401 South Mason Street
Fort Collins, CO
4 U13008-DrainageSummary-Final.doc
Low Impact Development (LID) Requirements
The developed site (Basin A1) of 2,830 sf will be entirely covered by the proposed
building footprint. Therefore, with no paving being provided, the site is not providing
pervious paved areas. In order to meet LID requirements, the rooftop of the building is
being proposed with approximately 970 sf of green roof resulting in a lower percent-
imperviousness and less overall runoff from the site compared to existing conditions.
Details of the green roof will be provided by the architect; however, calculations have
been provided for the green roof assuming characteristics of a rain garden with an
underdrain system. Refer to Appendix B for rain garden calculations.
Conclusions
In conclusion, the drainage system proposed within this drainage summary provides adequate
conveyance of the developed stormwater runoff from the proposed development to existing
discharge locations and drainage systems. It should also be noted that with this summary and
the corresponding design, every attempt has been made to minimize any negative impacts on
the downstream receiving waters. With the incorporation of the green roof, the site will
discharge a lower sediment load and less runoff than existing conditions.
In addition, the proposed design and ultimate construction shall comply with Chapter 10 of the
City of Fort Collins code in regards to Flood Prevention and Protection.
We understand that review by the City of Fort Collins is to assure general compliance with
standardized criteria contained in the Fort Collins Stormwater Criteria Manual (FCSCM). This
letter was prepared in compliance with technical criteria set forth in both the Urban Drainage
and Flood Control District (UDFCD) Urban Storm Drainage Criteria Manual and the FCSCM.
If you should have any questions or comments as you review this drainage summary, please
feel free to contact us at your convenience.
Sincerely,
United Civil Design Group, LLC
Kevin Brazelton, PE
Engineering Manager
APPENDIX A
Hydrology Calculations
401 South Mason Street
Fort Collins, CO Runoff Summary
Area Q2
Q100
(acre) (cfs) (cfs)
A1 A1 0.06 60% 0.36 0.56 0.07 0.36
OS1 OS1 0.08 85% 0.63 0.75 0.15 0.61
OS2 OS2 0.10 93% 0.75 0.85 0.21 0.82
Onsite Total 0.24 81% 0.58 0.71 0.42 1.80
A1 A1 0.06 0.88 0.68 0.79 0.13 0.51
OS1 OS1 0.08 77% 0.53 0.67 0.12 0.55
OS2 OS2 0.10 83% 0.61 0.73 0.17 0.71
Onsite Total 0.24 82% 0.60 0.72 0.42 1.77
Proposed Onsite Basins
Existing Onsite Basins
C100
C2
Basin %I
Design
Point
Calculations by: KRB
Date: 7/1/2014 D:\Dropbox\Projects\U13008-401 Mason\Drainage\Hydrology\U13008-Runoff.xlsx
401 South Mason Street
Fort Collins, CO Runoff Coefficients and % Impervious
Roof (1) Walks(1) Streets(1) Landscape(1&3)
%I = 90% %I = 90% %I =100% %I=2%
acres sf sf sf sf sf C2 C100
Proposed Onsite Basins
A1 A1 0.065 2829 1859 0 0 970 60% 0.36 0.56
OS1 OS1 0.083 3596 0 760 2346 490 85% 0.63 0.75
OS2 OS2 0.097 4244 0 1042 2993 209 93% 0.75 0.85
Onsite Total 0.245 10669 1859 1802 5339 1669 81% 0.58 0.71
Existing Onsite Basins
A1 A1 0.065 2829 1847 0 832 150 88% 0.68 0.79
OS1 OS1 0.083 3596 0 442 2346 808 77% 0.53 0.67
OS2 OS2 0.097 4244 0 584 2993 667 83% 0.61 0.73
Onsite Total 0.245 10669 1847 1026 6171 1625 82% 0.60 0.72
Notes:
(1) Recommended % Imperviousness Values from USDCM Vol 1 - Ch 5 - Table RO-3. Increased Lawns from 0% to 2% Impervious.
(2) Runoff C is based on %I, UDFCD Eq RO-7 and correction factors in Table RO-4.
(3) The landscaped area of Basin A1 denotes the approximate area of green roof being proposed with this project.
Composite Runoff
Basin Coefficients (2)
Areas
Composite
Imperviousness
(%I)
Total Total
Design
Pt.
Calculations by: KRB
Date: 10/9/2013 D:\Dropbox\U13008-401 Mason\Drainage\Hydrology\U13008-Runoff.xlsx
401 South Mason Street
Fort Collins, CO Time of Concentration
Area Length Slope ti
(2)
Length Slope
Velocity
(3) t
t
(4) Check
tc?
Total
Length
tc
(5)
acres ft % min ft % fps min min
u =
urban
ft min min
Proposed Onsite Basins
A1 A1 2,829 Roof 0.73 55 2 3.9 10 2 20 2.8 0.1 4.0 u 65 10 5
OS1 OS1 3,596 Street 0.90 30 4 1.2 35 0.2 20 0.9 0.7 1.9 u 65 10 5
OS2 OS2 4,244 Street 0.90 27 5 1.1 43 0.2 20 0.9 0.8 1.9 u 70 10 5
Existing Onsite Basins
A1 A1 2,829 Roof 0.73 60 2 4.1 21 0.6 20 1.5 0.2 4.3 u 81 10 5
OS1 OS1 3,596 Street 0.90 30 4 1.2 35 0.2 20 0.9 0.7 1.9 u 65 10 5
OS2 OS2 4,244 Street 0.90 27 5 1.1 43 0.2 20 0.9 0.8 1.9 u 70 10 5
Notes:
(1)
C5
based initial ground type and Table RO-5
(4)
tt
=L/(V*60 sec/min)
(2)
ti
= [1.8(1.1-C5
)L
1/2
]/S
1/3
, S= slope in %, L=length of overland flow (400' max)
(5)
tc
check (for urban or developed areas only) = total length/180 + 10
(3)
V=Cv
S
0.5
, S=watercourse slope in ft/ft, UDFCD Equation RO-4
(6)
min tc
= 5 min
Final
tc
(6)
tc Check for Urbanized
Basin
Initial Overland Flow Time (ti) Travel/Channelized Time of Flow (tt)
Design
Pt.
401 South Mason Street
Fort Collins, CO Rational Method Peak Runoff
Final
tc
(6) I2 I100 Q2 Q100
sf min in/hr in/hr cfs cfs
Proposed Onsite Basins
A1 2,829 5 0.36 0.56 2.85 9.95 0.068 0.364
OS1 3,596 5 0.63 0.75 2.85 9.95 0.147 0.613
OS2 4,244 5 0.75 0.85 2.85 9.95 0.209 0.820
Onsite Total 10,669 0.424 1.796
Existing Onsite Basins
A1 A1 2,829 5 0.68 0.79 2.85 9.95 0.126 0.510
OS1 OS1 3,596 5 0.53 0.67 2.85 9.95 0.124 0.552
OS2 OS2 4,244 5 0.61 0.73 2.85 9.95 0.169 0.710
Onsite Total 10,669 0.419 1.771
Design
Pt.
Peak Discharge
Area
Basin Runoff Coefficients Rainfall Intensity
C2 C100
Calculations by: KRB
Date: 10/9/2013 D:\Dropbox\U13008-401 Mason\Drainage\Hydrology\U13008-Runoff.xlsx
APPENDIX B
LID Water Quality Calculations
Sheet 1 of 2
Designer:
Company:
Date:
Project:
Location:
1. Basin Storage Volume
A) Effective Imperviousness of Tributary Area, Ia Ia = 60.0 %
(100% if all paved and roofed areas upstream of rain garden)
B) Tributary Area's Imperviousness Ratio (i = Ia/100) i = 0.600
C) Water Quality Capture Volume (WQCV) for a 12-hour Drain Time WQCV = 0.19 watershed inches
(WQCV= 0.8 * (0.91* i3 - 1.19 * i2 + 0.78 * i)
D) Contributing Watershed Area (including rain garden area) Area = 2,829 sq ft
E) Water Quality Capture Volume (WQCV) Design Volume VWQCV = cu ft
Vol = (WQCV / 12) * Area
F) For Watersheds Outside of the Denver Region, Depth of d6 = 0.60 in
Average Runoff Producing Storm
G) For Watersheds Outside of the Denver Region, VWQCV OTHER = 62 cu ft
Water Quality Capture Volume (WQCV) Design Volume
H) User Input of Water Quality Capture Volume (WQCV) Design Volume VWQCV USER = cu ft
(Only if a different WQCV Design Volume is desired)
2. Basin Geometry
A) WQCV Depth (12-inch maximum) DWQCV = 0.25 in
B) Rain Garden Side Slopes (Z = 4 min., horiz. dist per unit vertical) Z = 0.00 ft / ft
(Use "0" if rain garden has vertical walls)
C) Mimimum Flat Surface Area AMin = 41 sq ft
D) Actual Flat Surface Area AActual = 970 sq ft
E) Area at Design Depth (Top Surface Area) ATop = 970 sq ft
F) Rain Garden Total Volume VT= 20 cu ft
(VT= ((ATop + AActual) / 2) * Depth)
3. Growing Media
4. Underdrain System
A) Are underdrains provided?
B) Underdrain system orifice diameter for 12 hour drain time
i) Distance From Lowest Elevation of the Storage y = 2.50 ft
Volume to the Center of the Orifice
ii) Volume to Drain in 12 Hours Vol12 = 62 cu ft
iii) Orifice Diameter, 3/8" Minimum DO = 0.17 in MINIMUM DIAMETER = 3/8"
Design Procedure Form: Rain Garden (RG)
KRB
United Civil Design Group, LLC.
October 9, 2013
401 South Mason Street
Basin A1
Choose One
Choose One
18" Rain Garden Growing Media
Other (Explain):
YES
NO
UD-BMP_v3.02_RG-Basin 1.xls, RG 10/9/2013, 9:16 AM
Sheet 2 of 2
Designer:
Company:
Date:
Project:
Location:
5. Impermeable Geomembrane Liner and Geotextile Separator Fabric
A) Is an impermeable liner provided due to proximity
of structures or groundwater contamination?
6. Inlet / Outlet Control
A) Inlet Control
7. Vegetation
8. Irrigation
NO SPRINKLER HEADS ON THE FLAT SURFACE
A) Will the rain garden be irrigated?
Notes:
Design Procedure Form: Rain Garden (RG)
KRB
United Civil Design Group, LLC.
October 9, 2013
401 South Mason Street
Basin A1
Choose One
Choose One
Choose One
Sheet Flow- No Energy Dissipation Required
Concentrated Flow- Energy Dissipation Provided
Plantings
Seed (Plan for frequent weed control)
Sand Grown or Other High Infiltration Sod
Choose One
YES
NO
YES
NO
UD-BMP_v3.02_RG-Basin 1.xls, RG 10/9/2013, 9:16 AM
APPENDIX C
Drainage Exhibits
X X
X
X
X
LOT 7
LOT 8
CITY HIGH RISK FLOODWAY
CITY HIGH RISK FLOODWAY
CITY HIGH RISK 100-YEAR
FLOODPLAIN
EXISTING LOT LINE
EXISTING INLET
EXISTING INLET
A1
OS1
OS2
FLOODPLAIN CROSS SECTION #2446
FLOODPLAIN CROSS SECTION #2510
100-YEAR FLOOD ELEVATION-4996.6 (NAVD-88)
100-YEAR FLOOD ELEVATION-4996.3 (NAVD-88)
PREPARED FOR: DATE SUBMITTED:
The engineer preparing these plans will not be responsible for, or
liable for, unauthorized changes to or uses of these plans. All
changes to the plans must be in writing and must be approved by
the preparer of these plans.
CAUTION
COIN STREET MASON, LLC. 07/02/2014
401 SOUTH MASON STREET
10
U13008
PRELIMINARY
PLANS
NOT FOR CONSTRUCTION
Civil Engineering & Consulting
1501 Academy Court, Suite 203
Fort Collins, CO 80524
(970) 530-4044
www.unitedcivil.com
NONE KEVIN
D:\DROPBOX\PROJECTS\U13008-401 MASON\CADD\ET
HISTORIC DRAINAGE EXHIBIT.DWG
6/23/2014 11:26:17 AM
SME
HISTORIC DRAINAGE EXHIBIT
DR-1
N/A
10'
LEGEND
NOTES
1. PORTIONS OF THIS PROJECT ARE LOCATED WITHIN A CITY-REGULATED FLOODWAY AND FLOOD FRINGE OF THE OLD
TOWN BASIN AND IS SUBJECT TO THE REQUIREMENTS OF CHAPTER 10 OF THE CITY CODE.
EXISTING CURB & GUTTER
EXISTING CONCRETE
EXISTING BUILDING
EXISTING PROPERTY LINE
EXISTING LOT LINE
EXISTING FENCE
EXISTING GRAVEL
EXISTING PAVEMENT STRIPING
EXISTING WATER
X X
X
X
X
LOT 7
LOT 8
CITY HIGH RISK FLOODWAY
CITY HIGH RISK FLOODWAY
CITY HIGH RISK 100-YEAR
FLOODPLAIN
EXISTING LOT LINE
EXISTING INLET
EXISTING INLET
FLOODPLAIN CROSS SECTION #2446
A1
OS1
OS2
FLOODPLAIN CROSS SECTION #2510
100-YEAR FLOOD ELEVATION-4996.6 (NAVD-88)
100-YEAR FLOOD ELEVATION-4996.3 (NAVD-88)
100' PUBLIC
RIGHT-OF-WAY
100' PUBLIC
RIGHT-OF-WAY
MAIN ENTRY DOOR
EXIT STAIR DOOR
FLOODWAY PRE-CONSTRUCTION
SURVEY SECTION (TYP.)
(SEE NOTE 8)
PREPARED FOR: DATE SUBMITTED:
The engineer preparing these plans will not be responsible for, or
liable for, unauthorized changes to or uses of these plans. All
changes to the plans must be in writing and must be approved by
the preparer of these plans.
CAUTION
COIN STREET MASON, LLC. 07/02/2014
401 SOUTH MASON STREET
10
U13008
PRELIMINARY
PLANS
NOT FOR CONSTRUCTION
Civil Engineering & Consulting
1501 Academy Court, Suite 203
Fort Collins, CO 80524
(970) 530-4044
www.unitedcivil.com
NONE KEVIN
D:\DROPBOX\PROJECTS\U13008-401 MASON\CADD\CP
C5.00_DRAINAGE.DWG
7/2/2014 7:44:47 AM
SME
DRAINAGE EXHIBIT
C5.00
N/A
10'
0 10' 20'
SCALE: 1" = 10'
5'
CHECKED BY:
CHECKED BY:
CHECKED BY:
CHECKED BY:
CHECKED BY:
APPROVED:
LEGEND
NOTES
1. PORTIONS OF THIS PROJECT ARE LOCATED WITHIN A 100-YEAR CITY-REGULATORY FLOODWAY AND FLOOD FRINGE OF
THE OLD TOWN BASIN AND IS SUBJECT TO THE REQUIREMENTS OF CHAPTER 10 OF THE CITY CODE.
2. THE FIRST FLOOR OF THE PROPOSED MIXED-USE BUILDING IS BEING FLOOD PROOFED. REFER TO ARCHITECTURAL
PLANS FOR FLOOD PROOFING DETAILS AND SPECIFICATIONS. ALL FLOOD PROOFING MEASURES SHALL ADHERE TO
SECTION 10-38 OF CITY CODE AND THE REQUIREMENTS SET FORTH WITHIN THE CITY'S "FLOODPROOFING GUIDELINES". A
FLOOD PROOFING CERTIFICATE WILL BE REQUIRED PRIOR TO THE ISSUANCE OF A CERTIFICATE OF OCCUPANCY.
3. ALL DEVELOPMENT WITHIN THE CITY REGULATORY FLOODPLAIN MUST BE PRECEDED BY AN APPROVED FLOODPLAIN USE
PERMIT AND APPLICABLE FEES.
4. A FLOODPLAIN USE PERMIT AND NO RISE CERTIFICATION IS REQUIRED PRIOR TO PERFORMING ANY WORK WITHIN THE
FLOODWAY (I.E. CURB CUT, CURB & GUTTER, UTILITY WORK, LANDSCAPING, ETC.)
5. ALL SPOT ELEVATIONS AND BASE FLOOD ELEVATIONS AS SHOWN ON THIS DRAWING ARE PER VERTICAL CONTROL DATUM
NAVD 88.
6. NO STORAGE OF MATERIAL OR EQUIPMENT MAY OCCUR AT ANY TIME IN THE FLOODWAY BEFORE, DURING OR AFTER
CONSTRUCTION.
7. ANY ITEMS LOCATED IN THE FLOODWAY THAT CAN FLOAT (E.G. PICNIC TABLE, BIKE RACKS, ETC.) MUST BE ANCHORED.
8. ELEVATIONS AT EACH OF THE FLOODWAY PRE-CONSTRUCTION SURVEY SECTIONS WITH SPOTS DESIGNATED AS "FW"
(FLOODWAY) AND "TC" (TOP BACK OF CURB), ARE SHOWN PER THE PRE-CONSTRUCTION SURVEY PERFORMED BY
NORTHERN ENGINEERING. FINISHED GRADE ELEVATIONS MUST BE WITHIN 0.04' AT ALL THESE NOTED LOCATIONS PER
CITY OF FORT COLLINS STANDARDS. CONTRACTOR SHALL NOTE THAT A POST-CONSTRUCTION SURVEY WILL BE
REQUIRED TO VERIFY THAT THE FINISHED GRADES AT THESE LOCATIONS ARE WITHIN THE SAID TOLERANCE.
LIMITS OF DISTURBANCE
EXISTING CURB & GUTTER
EXISTING CONCRETE
EXISTING BUILDING
EXISTING PROPERTY LINE
EXISTING LOT LINE
EXISTING FENCE
EXISTING GRAVEL
EXISTING PAVEMENT STRIPING
EXISTING WATER
EXISTING SANITARY
EXISTING OVERHEAD ELECTRIC
EXISTING CABLE TV
EXISTING ELECTRIC
EXISTING STORM SEWER
EXISTING GAS
BASIN DESIGNATION
BASIN AREA (ACRE)
2 - YR RUNOFF COEFF.
100 - YR RUNOFF COEFF.
BASIN BOUNDARY
DESIGN POINT
FLOW DIRECTION
EXISTING CONTOUR
PROPOSED CONTOUR
CITY HIGH RISK FLOODWAY
CITY HIGH RISK 100-YEAR
FLOODPLAIN
RUNOFF SUMMARY
Basin Design
Point
Area
%I C2 C100
Q2 Q100
(acre) (cfs) (cfs)
Proposed Onsite Basins
A1 A1 0.06 60% 0.36 0.56 0.07 0.36
OS1 OS1 0.08 85% 0.63 0.75 0.15 0.61
OS2 OS2 0.10 93% 0.75 0.85 0.21 0.82
Onsite
Total 0.24 81% 0.58 0.71 0.42 1.80
Existing Onsite Basins
A1 A1 0.06 0.88 0.68 0.79 0.13 0.51
OS1 OS1 0.08 77% 0.53 0.67 0.12 0.55
OS2 OS2 0.10 83% 0.61 0.73 0.17 0.71
Onsite
Total 0.24 82% 0.60 0.72 0.42 1.77
DESCRIPTION ELEVATION
(NAVD-88)
CITY BASE FLOOD ELEVATION (BFE) * 4996.93
REGULATORY FLOOD PROTECTION ELEVATION (RFPE) 4998.43
LOWEST FLOOR ELEVATION (BASEMENT) 4985.50
FLOOD PROOFING ELEVATION 4998.50
HVAC EQUIPMENT ELEVATION (IN FLOODPROOFED
BASEMENT) 4985.50
FLOODWAY INFORMATION TABLE
* INFORMATION PROVIDED IN THE ABOVE TABLE IS BASED UPON THE
INTERPOLATED BFE LOCATED AT THE NORTHWEST CORNER OF THE
PROPOSED BUILDING.
NOTE:
1. THE TYPICAL FOOTING DETAIL IS SHOWN FOR REFERENCE ONLY AND IS NOT A
CONSTRUCTION DETAIL. CONTRACTOR SHALL REFER TO APPROVED ARCHITECTURAL
AND STRUCTURAL DRAWINGS FOR ALL FOUNDATION AND BUILDING DETAILS.
2. LOCATION OF HVAC EQUIPMENT IS TO BE LOCATED WITHIN THE FLOODPROOFED
BASEMENT.
TYPICAL FOOTING DETAIL
1. THE FOLLOWING PRODUCTS ARE BEING PROPOSED TO BE UTILIZED DURING CONSTRUCTION IN ORDER
TO FLOODPROOF THE BUILDING:
x EXTERIOR WALLS WILL BE WRAPPED WITH BITUTHENE 4000 FLEXIBLE PREFORMED WATERPROOF
MEMBRANE AND INSTALLED WITH DRAINAGE MATT AND 2-INCH RIDGED R-10 INSULATION.
x PREPRUFE WATERPROOFING MEMBRANE WILL BE INSTALLED UNDER THE SLAB. LAP SIDES OF
WALLS AND SEAL JOINTS PER MANUFACTURER SPECIFICATIONS.
x UNDER SLAB DRAINAGE SYSTEM AND PERIMETER DRAIN WITH SUMP PUMP TO BE INSTALLED.
x d, D/E EdZzKKZt/>> W ^dZ/E&>KKZZ/ ZKKZ͘d, &>KK^,/ >KKZz
^sE,dZ/D/^EKZD>h^ W ^dZ/EKKZd,d>^Kd^^&>KKWZKd d/KEKKZ͘
WHILE THE DOOR IS CLOSED AND LATCHED THE BUILDING WILL BE PROTECTED FROM FLOODING.
x THE STAIR EXIT DOOR WILL BE A PEDESTRIAN FLOOD DOOR. THE PD-520 IS A NORMAL USE
PEDESTRIAN DOOR THAT ALSO ACTS AS A FLOOD PROTECTION DOOR. WHILE THE DOOR IS CLOSED
AND LATCHED THE BUILDING WILL BE PROTECTED FROM FLOODING.
CONCRETE CAISSON FOUNDATION
PER STRUCTURAL DRAWINGS
FFE=4995.50
(NAVD-88)
FFE=4985.50
(NAVD-88)
FINISHED GRADE
VARIES
BFE=4996.93
(NAVD-88)
RFPE=4998.43
(NAVD-88)
FLOOD PROOFING ELEV.=4998.50
(NAVD-88)
CONTINUOUS WATERPROOFING
MEMBRANE
CONTINUOUS WATERPROOFING
MEMBRANE
WATERSTOP
PRE-CAST
CONCRETE WALL
CAST-IN-PLACE CONCRETE
FOUNDATION WALL
FLOODPROOF NOTES
PROJECT COORDINATES
VERTICAL DATUM:
BENCHMARK #1: CITY OF FORT COLLINS 1-11
SOUTHEAST CORNER OF MULBERRY ST. AND LOOMIS AVE. , AT THE NORTHEAST
CORNER OF A CONCRETE TRAFFIC SIGNAL BASE.
ELEVATION=5008.62 (NAVD 88 DATUM)
BENCHMARK #2: CITY OF FORT COLLINS 6-00
LOCATED ON A CATCH BASIN AT THE NORTHWEST CORNER OF
MULBERRY STREET AND COLLEGE AVENUE.
ELEVATION=4993.85 (NAVD 88 DATUM)
EXISTING SANITARY
EXISTING OVERHEAD ELECTRIC
EXISTING CABLE TV
EXISTING ELECTRIC
EXISTING STORM SEWER
EXISTING GAS
BASIN DESIGNATION
BASIN AREA (ACRE)
2 - YR RUNOFF COEFF.
100 - YR RUNOFF COEFF.
BASIN BOUNDARY
DESIGN POINT
FLOW DIRECTION
EXISTING CONTOUR
CITY HIGH RISK FLOODWAY
CITY HIGH RISK 100-YEAR
FLOODPLAIN
0 10' 20'
SCALE: 1" = 10'
5'
RUNOFF SUMMARY
Basin Design
Point
Area
%I C2 C100
Q2 Q100
(acre) (cfs) (cfs)
Proposed Onsite Basins
A1 A1 0.06 60% 0.36 0.56 0.07 0.36
OS1 OS1 0.08 85% 0.63 0.75 0.15 0.61
OS2 OS2 0.10 93% 0.75 0.85 0.21 0.82
Onsite
Total 0.24 81% 0.58 0.71 0.42 1.80
Existing Onsite Basins
A1 A1 0.06 0.88 0.68 0.79 0.13 0.51
OS1 OS1 0.08 77% 0.53 0.67 0.12 0.55
OS2 OS2 0.10 83% 0.61 0.73 0.17 0.71
Onsite
Total 0.24 82% 0.60 0.72 0.42 1.77
Initial
Ground
Type
C5
(1)
Cv
ti+tt
Calculations by: KRB
Date: 10/9/2013 D:\Dropbox\U13008-401 Mason\Drainage\Hydrology\U13008-Runoff.xlsx