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QUALITY ENGINEERING, LLC (970) 416-7891 2637 MIDPOINT DRIVE, SUITE E FORT COLLINS, COLORADO
December 8, 2016
Mrs. Heidi Hansen
City of Fort Collins Engineering Department
700 Wood Street
Fort Collins, Colorado 80521
RE: Supplemental Memorandum: No-Rise Certification to Floodplain Use Permit
112 West Magnolia Street, Fort Collins, Colorado 80525
QE Project No. 6300-01
This memorandum serves to supplement and further describe the work proposed with the Floodplain Use
Permit for Wells Fargo. The project site is located in the Old Town Basin 100-yr floodplain, a City of
Fort Collins regulatory floodplain. Since improvements area proposed within the High Risk Flood Fringe,
City Floodway, and Moderate Risk Floodplain, all work contained therein is subject to Chapter 10 of the
City of Fort Collins Municipal Code – Flood Prevention and Protection.
The subject property itself is located within a Moderate Risk Zone and High Risk Flood Fringe, as defined
by the City of Fort Collins’ 100-yr floodplain for the Old Town Basin. Additionally, the adjacent public
right-of-way for Magnolia Street and College Avenue both contain High Risk Floodway and Flood Fringe
areas. Appendix A illustrates the existing Flood Hazard Areas affecting 112 West Magnolia Street. The
High Risk Flood Fringe boundary line starts at the back edge of the sidewalk along Magnolia Street and
covers the south half of the site. The Moderate Risk Floodplain covers the north half of the site.
The proposed Wells Fargo parking lot improvements do not require a floodplain use permit because there
are no changes to the Old Town Basin HEC-RAS model. The HEC-RAS cross-section is located at an
existing access to the parking lot, but is modeled with an ineffective area past the right-of-way. The
proposed work for the site will abandon this existing access, and be replaced with curb and gutter. Since
the existing Old Town Basin Model represents the proposed conditions, the City of Fort Collins does not
require an analysis to justify no-rise. Other improvements in addition to the parking lot to be constructed
within the 100-yr High Risk Flood Fringe include paving, curbs, sidewalk, utilities, and landscaping.
These standard site work items are allowed within the 100-yr Old Town Basin High Risk Flood Fringe
without the need for special provisions or additional documentation. See the appendix for the location of
the HEC-RAS cross-section and the section view of the cross-section
However, a portion of the proposed improvements (curb & gutter and asphalt patch), also reside within
the 100-yr High Risk Floodway. Per Chapter 10 of the Municipal Code, all work within the floodway
must be accompanied by No-Rise Certification. The High Risk Floodway follows the back of sidewalk
past the centerline of Magnolia Street and College Avenue. This means that a portion of the driveway,
Page 2
sidewalk, and sidewalk chase will occur within the floodway. Curb and gutter will be replaced at existing
grade.
The primary technical justification used to support the No Rise Certification is the existing and as-built
survey information. Detailed existing survey data was gathered by King Surveying. A copy of the existing
conditions survey can be found in the appendix. The new curb, gutter, and sidewalk elements to be
constructed within the High Risk Floodplain shall not exceed the existing survey elevations when rounded
to the tenth of a foot. The permeable pavers underdrain storm system connection will also occur in the
floodway. All hardscape within the High Risk Floodway will be placed at or below existing grade, and
will be validated by an as-built survey.
There are two existing driveways along Magnolia Street and one existing driveway along College Avenue
that will be abandoned within the floodway to eliminate vehicular access to the site at these locations. A
new driveway cut and ADA access ramps will be installed on Magnolia Street to replace the abandoned
accesses. Filling in the old driveways and cutting in the new driveway should not impact the floodplain
since the existing driveways are represented with ineffective flow areas behind the right-of-way in the
hydraulic model. Existing and as-built survey points shall confirm that the elevation along the curb and
gutter is maintained. Therefore, the net effect results in no change to the floodway or flood fringe
boundaries and does not alter the Base Flood Elevations.
The purpose of Chapter 10 of the City of Fort Collins Municipal Code is to promote the public health,
safety and general welfare and to minimize public and private losses due to flood conditions in flood
hazard areas, which is accomplished by the governing methods and provisions contained therein. The
specific sections of Chapter 10 applicable to this particular Floodplain Use Permit are:
Sec. 10-27. Floodplain Use Permit – A floodplain use permit shall be obtained before any construction or
development within the flood fringe and floodway pursuant to Chapter 10. The sitework proposed herein
qualifies as development by Sec. 10-16.
Sec. 10-45. Floodway Evaluations – the proposed sitework within the floodway will result in no increase
in base flood elevations. This document accompanies the requisite No Rise Certification. Existing survey
information has been provided for the sitework area within the floodway. As-built survey information
shall be provided after the sidewalk, driveway, and parking lot improvements have been constructed to
ensure no change in the floodway boundary or increase in base flood elevations.
Sec. 10-111. Specific Standards for Nonstructural Development in Flood Fringe – There are two existing
driveways along Magnolia Street and one existing driveway along College avenue that will be abandoned
within the floodway to eliminate vehicular access to the site at these locations. A new driveway cut and
ADA access ramps will be installed on Magnolia Street to replace the abandoned accesses. These non-
structural improvements are allowed in the floodway contingent upon the No Rise Certification reference
in Sec. 10-45 above.
This memorandum serves as documentation of the sitework proposed within the 100-yr High Risk Flood
Fringe and Floodway of the Old Town Basin floodplain. Improvements will occur with the Development
Construction Permit for Wells Fargo. The applicable sections of Chapter 10 of the City of Fort Collins
Municipal Code are reference above. A post-construction certification shall also be supplied to ensure that
Page 3
the construction activities covered under this permit were consistent with the governing plans and
requirements. As-built field survey information shall be supplied in support of the post-construction
certification.
Please feel free to contact me if you have any questions or require additional information.
Sincerely,
QUALITY ENGINEERING, LLC Reviewed by,
Ramsey Pickard, EI Cody Geisendorfer, PE, CEM
Civil Designer I Principal Engineer
Attachments –
Appendix A
-Floodplain Use Permit
-Certification of No-Rise
-City of Fort Collins Flood Risk Map
-Cross Section Exhibit/Site Plan
-Cross-Section Profile
-Existing Survey completed by King Surveyors
Floodplain Use Permit
Section A: Owner and Property Information
Section B: Proposed Project Information
attach pg.3, crawl space worksheet
Remodels, Damaged Structures and Redevelopment Only
submit itemized cost list of improvements
submit County assessor’s or appraiser’s valuation of structure
Section C: Floodplain Information
highest BFE+freeboard
(if yes, include technical evaluation that shows “no-rise” per city Code 10-45
Section D: Survey Requirements
refer to City Code 10-37(d)
(not elevated or floodproofed)
Section E: Regulatory Requirements
Requesting a variance from City Code?
Freeboard
FEMA basin AND City basin freeboard:
Section F: Signature Block
If you have questions or need assistance filling out forms, contact Fort Collins Utilities at:
fcgov.com/stormwater
Project:
Address:
Description Quanity Unit Cost/Unit Total Cost
Permeable Pavers 5658 s.f. 11 $62,238.00
Concrete 35.5 c.y. 300 $10,650.00
Asphalt 4" Thick 878 s.y. 17 $14,926.00
PVC piping 411 ft 8 $3,288.00
Catch Basin 1 Each 300 $300.00
Mobilization 1 - 2000 $2,000.00
$93,402.00
$9,340.20
$102,742.20
Wells Fargo Parking Lot Improvemtens
112 West Magnolia Street, Fort Collins CO
Total:
10% Contingency:
Grand Total:
CERTIFICATION OF NO-RISE
ENGINEERING DEPARTMENT
Post Office Box 1190
Fort Collins, Colorado 80522-1190
(970) 498-5700
FAX (970) 498-7986
This is to certify that I am a duly qualified registered professional engineer licensed to practice in
the State of Colorado.
It is to further certify that the attached technical data supports the fact that proposed or as-built
(Name of Development) activities in the
floodway will not create an adverse rise or drop in the 100-year flood elevations, change the
watercourse location, or impact the 100-year flood elevations, floodway elevations, or floodway
widths on (Name of Stream) in accordance with
Section 4.2.2 of the Larimer County Land Use Code at published cross-sections in the Flood
Insurance Study for Larimer County revised on February 6, 2013 and will not create an adverse
rise or drop in the 100-year flood elevations, change the watercourse location, or impact the 100-
year flood elevations, floodway elevations, or floodway widths at unpublished cross-section in
the vicinity of the proposed development.
Attached are the following documents that support my findings:
Date:
Signature:
Printed Name:
Title:
{SEAL}
S COLLEGE AVE
W MAGNOLIA ST
. Printed: 03/25/2016
All floodplain boundaries
are approximate.
This information is based on the Federal Emergency Management
Agency (FEMA) Flood Insurance Rate Map (FIRM) and the City of
Fort Collins Master Drainageway Plans. This letter does not imply
that the referenced property will or will not be free from flooding or
damage. A property not in the Special Flood Hazard Area or in a
City Designated Floodplain may be damaged by a flood greater
than that predicted on the map or from a local drainage problem
not shown on the map. This map does not create liability on the
part of the City, or any officer or employee thereof, for any damage
that results from reliance on this information.
City Flood Risk Map
Moderate Risk
May include:
- Areas of FEMA 500-year floodplain (FEMA Zone X-shaded).
- Areas of FEMA or City 100-year floodplain (sheet flow) with
average depths of less than 1 foot.
- Areas protected by levees from the 100-year flood.
Low Risk
Areas outside of FEMA and City mapped 100-year and 500-year
floodplains. Local drainage problems may still exist.
City Flood Fringe - May Include:
- Areas of FEMA 100-year floodplain (FEMA Zones A, AE, AO, and AH)
- Areas of City 100-year floodplain including ponding areas and sheet
flow areas with average depths of 1-3 feet.
There is a 1% annual chance that these areas will be flooded.
High Risk
City Floodway - Area of 100-year floodplain with greatest depths and
fastest velocities.
0 15 30 60 90 120
Feet
PLANTING AREA
7
8
5
19.0' TYP
9.0' TYP
24.0' 24.0' 24.0'
25.0'
24.0'
5.0'
5.0'
5.5'
6.00'
6.0'
30.9'
8.0' 8.0' 8.0'
6.0'
3.00'
64.2'
11.5'
6.5'
11.5'
5.0'
25.0
4' SCREEN WALL
ACCESS RAMP WITH
TRUNCATED DOMES (TYP)
UNDERDRAIN
INV: 93.79'
UNDERDRAIN
INV: 93.58'
UNDERDRAIN
INV: 93.60'
UNDERDRAIN
INV: 93.33'
UNDERDRAIN
INV: 93.77'
UNDERDRAIN
INV: 93.51'
UNDERDRAIN
INV: 93.75'
UNDERDRAIN
INV: 94.06'
PROPOSED
4' MANHOLE
PROPOSED
2' U-CHANNEL
PROPOSED BIKE RACK
6
(
1
(
1
:
6
:
MAGNOLIA STREET
UNDER DRAIN
INV: 93.13'
EXISTING 5' SW
1000 1050 1100 1150 1200 1250
4990
4992
4994
4996
4998
5000
Lincoln Center Floodplain revision Plan: Post-Project 2/23/2011
U/S FACE COLLEGE
Station (ft)
Elevation (ft)
Legend
EG 100 yr
WS 100 yr
Crit 100 yr
EG 10 yr
WS 10 yr
Crit 10 yr
WS 2 yr
EG 2 yr
Crit 2 yr
Ground
Ineff
Bank Sta
.06 .016 .06
KING SURVEYORS
650 E. Garden Drive | Windsor, Colorado 80550
phone: (970) 686-5011 | fax: (970) 686-5821
1
P:\20160589\DWG\20160589TOP.dwg, 7/13/2016 8:48:54 AM
EXISTING AVENUE
HEC-RAS CROSS-SECTION
RIVER STATION 2068
LINE TABLE
LINE #
L1
L2
L3
L4
L5
L6
L7
L8
L9
L10
L11
L12
L13
L14
L15
L16
BEARING
6
:
6
(
1
(
6
(
1
(
6
(
6
:
6
(
6
:
6
(
1
(
6
(
6
:
6
(
1
(
6
(
DISTANCE
2.00
161.53
62.50
17.50
3.50
25.00
3.50
14.50
9.00
16.50
3.50
25.00
3.50
16.50
9.00
17.50
LINE TABLE
LINE #
L17
L18
L19
L20
L21
L22
L23
L24
L25
L26
L27
L28
L29
L30
L31
L32
BEARING
1
(
1
(
6
(
1
(
1
(
1
:
1
(
6
(
1
:
6
(
1
:
1
:
6
(
1
(
6
:
6
:
DISTANCE
14.02
3.18
6.96
3.35
23.07
15.50
46.00
15.50
14.50
32.00
34.00
32.00
34.00
12.25
6.11
22.54
CURVE TABLE
CURVE #
C1
C2
C3
C4
C5
C6
C7
C8
C9
C10
LENGTH
3.927
2.356
2.356
2.356
2.356
2.356
12.329
11.725
2.356
2.356
RADIUS
2.500
1.500
1.500
1.500
1.500
1.500
7.545
7.381
1.500
1.500
DELTA
090.0000
090.0000
090.0062
090.0000
090.0000
090.0000
093.6316
091.0163
090.0000
090.0000
CURVE TABLE
CURVE #
C11
C12
C13
C14
C15
C16
C17
C18
C19
LENGTH
3.927
3.927
2.356
3.927
2.356
3.927
2.356
3.927
2.356
RADIUS
2.500
2.500
1.500
2.500
1.500
2.500
1.500
2.500
1.500
DELTA
090.0000
090.0000
090.0000
090.0000
090.0000
090.0000
090.0000
090.0000
090.0000
10'
SCALE: 1" = 10'
0 20'
N
NOTE:
1.) ALL LINE AND CURVE TAGS ARE
MEASURED AS THE FLOWLINE UNLESS
OTHERWISE NOTED
WELLS FARGO PARKING LOT IMPROVEMENTS
112 WEST MAGNOLIA STREET
FORT COLLINS CO, 80525
CITY OF FORT COLLINS, COLORADO
UTILITY PLAN APPROVAL
FOR BURIED UTILITY INFORMATION
THREE (3) BUSINESS DAYS
BEFORE YOU DIG
CALL 811
(OR 1-800-922-1987)
UTILITY NOTIFICATION
CENTER OF COLORADO (UNCC)
WWW.UNCC.ORG
R