HomeMy WebLinkAboutA22 ITEM #:
DATE: 11/12/14
CITY OF AMES
DEPARTMENT OF PLANNING AND HOUSING
REPORT TO THE ZONING BOARD OF ADJUSTMENT
REQUEST: A CONDITIONAL USE PERMIT TO ALLOW AN ALTERNATIVE METHOD
OF ELEVATION IN THE FLOODWAY FRINGE FOR TWO MULTI-FAMILY
APARTMENTS AT 1204 S. 4T" STREET
PROPERTY OWNER: Brian Hoyle, American Healthcare Investment, LLC
APPLICANT: Scott Renaud
LOCATION: 1204 S. 4t" Street
ZONING: High Density Residential
PROJECT DESCRIPTION:
American Healthcare Investment, LLC owns and operates the Riverside Manor skilled
healthcare facility at 1204 S. 4" Street. The 11.23 acre site is zoned RH High-Density
Residential. Much of the site lies within the Squaw Creek 100-year flood plain
(Floodway Fringe), including the existing Riverside Manor building. A southern portion
of the site also lies within the Floodway. A map of the location and the flood plain is
found in Attachment 1.
The property owner intends to sell approximately 9 acres of the site to allow for
construction of multi-family apartments. One building will have 62 dwelling units with
176 bedrooms. The other will have 72 dwelling units with 200 bedrooms. Parking will be
provided at the south end of the lot, within the Floodway. These uses are allowed by the
underlying RH zoning subject to conformance with City's development standards. The
requested Conditional Use Permit is for an alternative method of meeting the
Floodway Fringe requirement of adding fill to a site to construct the lowest floor
of the building three feet above the 100-year flood level (Base Flood Elevation + 3
feet).
As noted above, the City of Ames requires that the lowest floor of a structure must be at
least BFE + 3. (This building is proposed as BFE + 4.) For a residential structure, this
elevation must be extended to 18 feet around the perimeter of the building. The reason
for this requirement is often cited as allowing a place for the residents to await
evacuation in the event of a flood. Commercial buildings do not require an 18-foot
perimeter at BFE +3. Attachment 2 provides an overview of flood plain management.
The applicant requests an alternative method of compliance for elevating the
building to the BFE +3 requirement by meeting the elevation requirement for the
building, but to only meet the 18-foot perimeter requirement on three of the four
sides of each building and substitute a retaining wall for the 4t" side.
The developer proposes to construct one of the apartment buildings along the Floodway
boundary and elevate it along that line by means of a structural retaining wall that also
serves as the foundation of the buildings. The other building will be set back about 5
feet from another retaining wall. These "alternate method(s) of elevating" require
approval of a Conditional Use Permit from the Zoning Board of Adjustment. The BFE +
3 elevation requirement will be met around all the areas of the two buildings not
adjacent to the Floodway. See attached site plan.
The applicant contends that requiring the fill of 18 feet around the perimeter of the
buildings will preclude the project from achieving the desired design and the required fill
is not permitted within the floodway. Additionally, the substitute retaining wall will have
no effect on flooding compared to the standard fill requirements of the Floodway Fringe.
APPLICABLE LAW:
The laws applicable to this case are as follows.-
Chapter 9, Section 9.1(2) of the Ames Municipal Code states:
It is the purpose of this ordinance to promote the public health, safety, and
general welfare by minimizing those flood losses described in Section 9.1(2) with
provisions designed to:
(a) Reserve sufficient floodplain area for the conveyance of flood flows so that
flood heights and velocities will not be increased by greater than one (1)
foot.
(b) Restrict or prohibit uses which are dangerous to health, safety, or property
in times of flood or which cause excessive increases in flood heights or
velocities.
(c) Require that uses vulnerable to floods, including public utilities, which
serve such uses, be protected against flood damage at the time of initial
construction or substantial improvement.
(d) Protect individuals from buying lands, which are unsuited for intended
purposes because of flood hazard.
(e) Assure that eligibility is maintained for property owners in the community
to purchase flood insurance through the National Flood Insurance
Program.
Section 9.5 Floodway Fringe Overlay District
(2) Performance Standards. All uses must be consistent with the need to minimize
flood damage and shall meet the following applicable performance standards.
(a) All structures shall
(i) be adequately anchored to prevent flotation, collapse or lateral
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movement of the structure,
(ii) be constructed with materials and utility equipment resistant to flood
damage, and
(iii) be constructed by methods and practices that minimize flood damage.
(b) Residential buildings. All new or substantially improved residential structures
shall have the lowest floor, including basements, elevated a minimum of three (3)
feet above the base flood elevation level. Construction shall be upon
compacted fill which shall, at all points, be no lower than three (3) feet
above the base flood elevation level and extend at such elevation at least
18 feet beyond the limits of any structure erected thereon. Alternate methods
of elevating (such as piers) may be allowed, subject to favorable consideration by
the Zoning Board of Adjustment and issuance of a Conditional Use Permit, where
existing topography, street grades, or other factors preclude elevating by fill. In
such cases, the methods used must be adequate to support the structure as well
as withstand the various forces and hazards associated with flooding. All new
residential buildings shall be provided with a means of access which will be
passable by wheeled vehicles during the base flood elevation.
Section 9.5 (2)(k)(ii):
New and substantially improved structures must be designed (or modified) and
adequately anchored to prevent flotation, collapse, or lateral movement of the
structure resulting from hydrodynamic and hydrostatic loads, including the effects
of buoyancy.
Chapter 9, Section 9.7 of the Ames Municipal Code states:
3(e)(ii) a. Factors upon which the decision of the Board shall be based. In passing
upon requests for Conditional Uses or Variances, the Zoning Board shall consider
all relevant factors specified in other sections of the ordinance and:
(1) The danger to life and property due to increased flood heights or velocities
caused by encroachments.
(2) The danger that materials may be swept onto other lands or down stream
to the injury of others.
(3) The proposed water supply and sanitation systems and the ability of these
systems to prevent disease, contamination, and unsanitary conditions.
(4) The susceptibility of the proposed facility and its contents to flood damage
and the effect of such damage to the individual owner.
(5) The importance of the services provided by the proposed facility to the
community.
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(6) The requirements of the facility for a flood plain location.
(7) The availability of alternative locations not subject to flooding for
the proposed use.
(8) The compatibility of the proposed use with existing development and
development anticipated in the foreseeable future.
(9) The relationship of the proposed use to the comprehensive plan and flood
plain management program for the area.
(10) The safety of access to the property in times of flood for ordinary and
emergency vehicles.
(11) The expected heights, velocity, duration, rate of rise, and sediment
transport of floodwater expected at the site.
(12) Such other factors which are relevant to the purpose of the ordinance.
FINDINGS OF FACTS:
Staff makes the following findings of facts:
1. The subject site is approximately 9 acres in size with the majority of the site
located within the Floodway Fringe and a portion of the site within the
Floodway.
2. The proposed structures lie within the Floodway Fringe and adjacent to the
Floodway of Squaw Creek.
3. The Base Flood Elevation of the site is 895 feet NGVD 1929. The Regulatory
Flood Elevation (BFE + 3) is 898 feet.
4. The lowest floor elevation is proposed at 899 feet.
5. The 898 elevation extends on compacted fill to 18 feet from the perimeter of
the building on three sides, excepting the side with the retaining wall.
6. The top of the retaining wall is 898 feet.
7. One building will have a retaining wall integrated into the foundation of the
building. The other building will have a retaining wall about 5 feet away. These
retaining walls are in lieu of the 18 foot perimeter elevation requirements.
8. The proposed retaining wall will be designed by an engineer and reviewed as
part of the building permit process to ensure compliance with FEMA standards
for resistance to hydraulic forces prior to issuance of a building permit.
9. The proposed grading of the site provides for an elevation of 895 feet (BFE is
895 feet) from the buildings to the S. 4th Street right-of-way providing an
evacuation route for residents of both apartments.
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CONCLUSIONS:
The applicant is seeking approval of a conditional use permit to allow an alternative
method of elevating a residential structure. The applicant seeks to use a retaining wall
to elevate one side of one of the structures, rather than extending fill a distance of 18
feet from the perimeter of the building. The other building will have a separate retaining
wall about 5 feet from its foundation. In all other respects, the performance standards of
the flood plain regulations are met.
The applicant has provided a conceptual design for the engineered wall, prepared by a
professional engineer licensed in Iowa, and will have a more detailed design at the time
of building permit application. That design, too, will be prepared by a licensed
professional engineer and will ensure compliance with FEMA standards for resistance
to hydraulic flows. Inspections and planning staff will review the design prior to issuing a
building permit.
The alternative method of elevating a structure has not been used frequently in Ames.
In one instance in 2011 , the apartments known as The Grove on S. 16th Street sought
approval for the use of a retaining wall (separate from their foundation) for elevating the
structure due to the structure's proximity to a property line. In 2012, the South Meadows
Cooperative on S. 5th Street sought approval to use the existing garages below to
rebuild a fire-damaged structure above. In both these instances, approval was granted.
PUBLIC COMMENT:
This office has received several calls about the grading that is being undertaken on this
site since September. Many have expressed concern that development in this area will
have an impact on future flood levels. Since mailed notice of this specific case was sent
on October 31, 2014 this office has received one phone call asking for more specific
information about the case. The caller expressed no opposition or support.
ALTERNATIVES:
1 . The Zoning Board of Adjustment can approve the Conditional Use Permit to
Allow the Alternative Method of Elevation for the construction of two apartment
buildings at 1204 S. 4th Street using a structural retaining wall along those
portions of the buildings adjacent to the Floodway with the adoption of the
findings of fact and conclusions stated herein and with the condition that a final
floodwall/retaining wall design be provided by a professional engineer licensed in
Iowa that states that the proposed wall will ensure compliance with FEMA
standards for resistance to hydraulic forces prior to issuance of a building permit.
2. The Zoning Board of Adjustment can deny the Conditional Use Permit to Allow
the Alternative Method of Elevation for the construction of two apartment
buildings at 1204 S. 4th Street using a structural retaining wall along those
portions of the buildings adjacent to the Floodway, if the Board determines that
the request does not meet the standards and purposes of the ordinance.
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3. Action on this request can be postponed and referred back to City staff and/or
the applicant for additional information.
DEPARTMENT RECOMMENDATION:
Based upon the Findings of Fact and Conclusions above and after consideration of the
factors in Section 9.7.3 (e) of the Flood Plain Zoning Regulations, that conditional use
permit can be found consistent overall with the standards and purposes of the
ordinance. Therefore, it is the recommendation of the Department of Planning and
Housing that the Zoning Board of Adjustment approve with conditions the Conditional
Use Permit to Allow the Alternative Method of Elevation for the construction of two
apartment buildings at 1204 S. 4t" Street using a structural retaining wall along those
portions of the buildings adjacent to the Floodway.
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ATTACHMENT 1: LOCATION AND FLOOD PLAIN
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Feet r�_�i Fioodway Overlay
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a Fioodway Fringe Overlay
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ATTACHMENT 2
FLOOD PLAIN REGULATIONS, IN GENERAL:
The City participates in the National Flood Insurance Program (NFIP). Because of that
participation, property owners and residents are able to purchase flood insurance from
private agents. As a condition of that participation, the City must have flood insurance
rate maps prepared and adopt regulations governing development in the special flood
hazard area. The most recent maps were adopted on October 16, 2014 and the
regulations exceed the minimum regulatory requirements of the Iowa Department of
Natural Resources.
The regulations are intended to allow development (residential, commercial, industrial,
recreational, etc) within the Floodway Fringe through elevation or floodproofing of
structures. Development within the Floodway Fringe is expected to cause up to a one
foot increase in the water level of 100-year flood.
Only limited development is allowed within the Floodway—parking lots, recreation fields,
golf courses, for example. No habitable structures and no fill that will cause ANY rise in
the water level of a 100-year flood are permitted.
The figure below shows a schematic cross section of a stream. The 100-year flood plain
is shown, comprising the Floodway and Floodway Fringe. The Floodway is calculated
by computer model, showing the impacts of increasing the fill in the Floodway Fringe
until the water surface level increases 1 foot. The resulting unfilled area is the
Floodway.
LirnitofFloodpl.airr tot Unencroached I0p-ve_arFlood
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RoC❑�na Fnnrle F[ordl,,,�v FInGrfin:=�rFrnige
— Strearn Charnel
nCr BCYinla"t Ert-To3r_nrnerlt
C D
Fill Fill
f ..........: ................... B. .... ...
Ground Surface
£Lrrchange
Bate.Flood Elevation(BFF..)—
-rep+or Er,rrnathrnent
F'ro i i elevation e,at e
F,'aising ground surfi_:ce kmll not enci oachmer t Cfr flnndplaM
Cause surchatge that exceeds tide
indicated standards Lme.'.-B is the flood ele,.%atinn before encroacPirrien[
Line C-D is the flu'ocl eie..ati on after encrnarhment
lurch arraE n t tr:i e:��ed 1.0 n !FEMN.requiternr ntt or I scar heii�ht It :{,�i:ifiecl':ry ct�rr�rnuruC;+
Flood plainEncroachment-and•Floodway
Because development in the Floodway Fringe will likely cause an increase of up to 1
foot in the water surface level of a 100-year flood, the state requires any new structure
to be built 1 foot above the BFE (BFE + 1). The City's regulations require BFE + 3.
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