HomeMy WebLinkAboutA5 ITEM #:
DATE: 06-10-15
CITY OF AMES
DEPARTMENT OF PLANNING AND HOUSING
REPORT TO THE ZONING BOARD OF ADJUSTMENT
DATE PREPARED: June 5, 2015
CASE FILE NO.: ZBA-15-06
REQUEST: Conditional Use Permit to allow a new wireless communication tower in the
Floodway at 600 S. Maple Avenue
PROPERTY OWNER: City of Ames
APPLICANT: Verizon Wireless, represented by Michael Howley of Insite RE, Inc.
ZONING: "SGA" (Special-Government/Airport) and Floodway Overlay District
BACKGROUND AND PROJECT DESCRIPTION:
Verizon Wireless, represented by Michael Howley, with Insite RE, Inc., is seeking to
construct a new monopole cell tower on the property located at 600 S. Maple Avenue.
The site is located along the north edge of the Floodway of Squaw Creek. The site is
located mostly within the Floodway Fringe, which has lesser development standards
but, because a portion is within the Floodway, the entire project must meet those
Floodway standards. Development within the Floodway is allowed for a limited number
of uses and only if Floodway performance standards are met.
The new tower and associated equipment shelter would be located in a lease area
along the north boundary of the property with an access easement to the S. Maple
Avenue right-of-way (see Attachment A: Location and Floodway Map).
The Verizon improvements will be within a 33 feet by 59 feet compound. The leased
premises are 33 feet by 84 feet, which includes an area for the future inclusion of two
additional carriers. Within the Verizon area will be a 120 foot tall monopole (129 foot
with the lightning rod) and an elevated equipment platform. The pole has an eight-foot
diameter at its base.
The equipment platform is supported by multiple columns and is 17.33 feet by 35.33
feet and will rise 13 feet above ground. The platform will contain the equipment cabinets
and emergency generator inside a shelter. The shelter provides security and screening
for the equipment. Access to the platform is by stairs on the north side of the platform. A
security fence is located along the top of the platform.
The flood plain regulations were adopted to 1) use construction techniques and
restrictions on the type of use to minimize the risk of loss of life and reduce property
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damage, and 2) use design considerations to avoid an increase in depth of flood waters
during a flood event.
At the proposed tower site, the ground elevation is about 888' (all elevations are in
National Geodetic Vertical Datum 1929, or NGVD 29). The base flood elevation (BFE,
the water surface level of a flood event having a one percent chance of occurring in any
given year, or 100-year flood event) is 894.6.' Therefore, in a 100-year flood, it is
anticipated that the ground will be inundated by 6.6 feet of flood water.
The City of Ames flood plain regulations requires elevation or floodproofing to three feet
above BFE for an elevation of 897.6' at this location. The bottom of the steel platform,
upon which the equipment shelter sits, is at 900.' This is 5.4 feet above BFE, or 12
feet above the natural grade.
APPLICABLE LAW:
Specific criteria and design standards for wireless communication facilities are found in
Section 9.4.
Conditional Uses Allowed
(2) Conditional Uses. The following uses which involve structures (temporary or
permanent), fill, or storage of materials or equipment may be permitted only upon
issuance of a Conditional Use Permit by the Zoning Board of Adjustment as
provided for in Sec. 9.7. Such uses must also meet the applicable provisions of
the Floodway Overlay District Performance Standards.
(a) Uses or structures accessory to open-space uses.
(b) Circuses, carnivals, and similar transient amusement enterprises.
(c) Drive-in theaters, new and used car lots, roadside stands, signs, and
billboards.
(d) Extraction of sand, gravel, and other materials.
(e) Marinas, boat rentals, docks, piers, wharves.
(f) Utility transmission lines, underground pipelines.
(g) Other uses similar in nature to uses described as permitted uses or
listed conditional uses, which are consistent with the performance
standards of Subsection (3) below and the general spirit and purpose of
this ordinance.
Staff has found the proposed tower is consistent with (g) in that it is similar to a utility
pole in its nature as an automated use and in its form as singular pole like a
transmission tower.
Floodway Performance Standards
Section 9.4(3) describes the performance standards for conditional uses that are
allowed by the Board. Following the code excerpts are staff comments. The applicant's
statements addressing these standards are included in the attached application.
(3) Performance Standards. All Floodway Overlay District uses allowed as a
Permitted or Conditional Use shall meet the following standards-
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(a) No use shall be permitted in the Floodway Overlay District that would
result in any increase in the base flood elevation level. Consideration of
the effects of any development on flood levels shall be based upon the
assumption that an equal degree of development would be allowed for
similarly situated lands. Evidence required will be a hydraulic study
performed by a registered professional engineer for the area of drainage
involved.
(b) All uses within the Floodway Overlay District shall:
(i) Be consistent with the need to minimize flood damage.
(ii) Use construction methods and practices that will minimize and
resist flood damage.
(iii) Use construction materials and utility equipment that are
resistant to flood damage.
(c) No use shall affect the capacity or conveyance of the channel or
floodway or any tributary to the main stream, drainage ditch, or any other
drainage facility or system.
(d) Structures, buildings and sanitary and utility systems, if permitted, shall
meet the applicable performance standards of the Floodway Fringe
Overlay District and shall be constructed or aligned to present the
minimum possible resistance to flood flows.
(e) Buildings, if permitted, shall have a low flood damage potential and
shall not be for human habitation.
(f) Storage of materials or equipment that are buoyant, flammable,
explosive or injurious to human, animal or plant life is prohibited. Storage
of other material may be allowed if readily removable from the Floodway
Overlay District within the time available after flood warning.
(g) Watercourse alterations or relocations (channel changes and
modifications) must be designed to maintain the flood carrying capacity
within the altered or relocated portion. In addition, such alterations or
relocations must be approved by the Department of Natural Resources.
(h) Any fill allowed in the floodway must be shown to have some public
beneficial purpose and shall be limited to the minimum amount necessary.
(i) Pipeline river or stream crossings shall be buried in the streambed and
banks or otherwise sufficiently protected to prevent rupture due to channel
degradation and meandering or due to the action of flood flows.
(j) It shall be the responsibility of adjacent property owners to maintain the
location and carrying capacity of the floodway adjacent to their property.
a) The applicant has provided an "Engineering `No-Rise' Certificate" in which the
engineer states that the project will not result in an increase in base flood
elevations in the Floodway. The rationale for the no rise is due to the removal of
similar amount of existing obstructions (trees) as to that of tower and due to the
type of flooding that occurs in this wooded area. The complete analysis is
included in Attachment B: No-Rise Analysis.
b) The support columns will be designed to be adequate to prevent flotation,
collapse, or lateral movement in the event of flood. The elevated platform will
provide protection to at least three feet above the base flood elevation. The
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summary from the Structural Analysis Report is included in Attachment C:
Structural Analysis Report.
c) As noted in the No-Rise Certificate, the carrying capacity of the stream will not be
impacted. The removal of several trees offsets the installation of the platform
supports. In addition, the platform supports are aligned so as to present the least
resistance to the direction of flood flows.
d) The structure is not habitable—it merely shelters the equipment from the
elements, screens the equipment from view, and prevents unauthorized access.
It, along with all electrical connections, will be elevated to more than 3 feet above
the base flood elevation.
e) There will be no buildings.
f) There will be no storage within the Floodway.
g) No watercourse alterations will occur.
h) Minimal fill to provide drainage for the access road and platform site will be
imported to the site. Any excess from construction will be removed from the site.
i) The project does not include any stream crossings.
j) The City is the ultimate responsible party for maintaining the area within and
around the project site.
Factors Upon Which the Decision Shall be Based
Section 9.7(3)(e)(2)(a) describes the factors that the Board must consider when
approving a Conditional Use Permit.
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 this 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
downstream 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 on the individual owner.
5. The importance of the services provided by the proposed facility to the
community.
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.
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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 the flood water expected at the site.
12. Such other factors which are relevant to the purpose of this ordinance.
In considering these factors, staff offers the following comments for consideration by the
Board:
1. There is no anticipated danger to life due to a flood event as the proposed project
is an uninhabited equipment shelter and cell tower.
2. There will be no materials stored on-site. Everything is within an enclosed shelter
elevated at least three feet above the base flood elevation. There will be nothing that
can be swept downstream in the event of a flood.
3. No water or sanitary sewer services are provided to this site.
4. It is anticipated that this site will be inundated during a flood event. However, the
support columns of the elevated platform will be designed to withstand anticipated
hydraulic forces in a flood event.
5. Verizon, as part of their RF justification, has identified a need for improved
services in this area. The antenna will improve not just cellular phone service, but also
broadband internet and mobile access. The Ames Police Department has indicated that
improved service is needed in this area for full functionality of in-car broadband service.
6. The City has worked with the applicant for over two years in possible sites for this
antenna. Because of the adjacent residential neighborhood, a non-obtrusive site was
desired.
7. Alternative sites were considered in the area. However, none were acceptable due
to visibility or inability to obtain a lease or purchase.
8. The site is heavily wooded, which will provide significant screening of the base of
the tower and the equipment platform. The cell tower will be visible from the IDOT
property to the north. It is a maintenance facility having considerable heavy equipment
on site. No further development, other than possible outdoor park facilities, is
anticipated.
9. The Ames Land Use Policy Plan identifies the area of the Floodway as Parks and
Open Space. The proposed tower is not inconsistent with these designations. The tower
is consistent with the flood plain management regulations in that it is designed to
withstand damage from floods and does not increase base flood elevations.
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10. The area is Floodway and no access is anticipated other than for routine tower
maintenance. Since the facility is not habitable and should be fully functional in the
event of a flood, no emergency access is anticipated.
11. The tower and platform supports are not expected to cause an increase in flood
depths, water velocities, or sedimentation flows due to site mitigations of removing
existing obstructions of trees.
PUBLIC COMMENTS:
Notification was made to all owners of property within 200 feet. In addition, a notice of
public hearing was placed on the property. As of this writing, no comments have been
received.
CONCLUSIONS:
City staff has reviewed the information submitted by the applicant. Staff concludes that
the criteria of Chapter 9, Flood Plain Zoning Regulations are met.
ALTERNATIVES:
1. The Zoning Board of Adjustment may approve the Conditional Use Permit for a cell
tower in the Floodway at 600 South Maple Avenue, based on the findings of fact and
conclusions stated herein, as detailed on the submitted Site Plan.
2. The Zoning Board of Adjustment may deny the Conditional Use Permit for cell tower
in the Floodway at 600 South Maple Avenue, if the Board finds and concludes that
the proposed Conditional Use Permit is not consistent with the minimum standards
of the flood plain regulations.
3. The Zoning Board of Adjustment may continue this request to a future meeting of the
ZBA for a Conditional Use Permit for a cell tower in the Floodway to allow the
applicant to revise the submittal to meet all minimum standards of the flood plain
regulations.
RECOMMENDED ACTION:
Staff finds that the proposed use is allowable within the Floodway and that the design of
the structure meets the performance standards and the conditional use permit factors.
Based upon the Findings of Fact and Conclusions above, it is the recommendation of
the Department of Planning and Housing that the Zoning Board of Adjustment act in
accordance with Alternative #1.
SAPLAN_SHR\Council Boards Commissions\ZBA\Conditional Use in Floodway\600_S_Maple_Cell_Tower_CUP-06-10-15.docx
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Attachment A: Location and Floodway Map
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Attachment B: No-Rise Analysis
E&A CONSULTING GROUP, INC.
ENGINEERING•PLANNING•ENVIRONMENTAL&FIELD SERVICES
330 NORTH 117TH STREET www.eacg.com PHONE:402.895,4700
OMAHA,NE 68154-2509 FAX 402.895.3599
May 13,2015
Mr.Charlie Kuester
Planner
Ames City Hall
515 Clark Avenue
Ames, IA 50010
RE: Verizon Tower and Building on Squaw Creek
42.017049'N,-93.623455°E
No Rise Certification
E&A Project#: P2014.073.001
Dear Mr. Kuester,
E&A Consulting Group,Inc.(E&A)has been asked to update a no net rise certification previously
submitted on May 13,2014,due to an updating mapping for the area. E&A is again evaluating the
effects of constructing a communications tower and support building on the grounds approximately
440 feet east of South Maple Avenue and 790 feet south of South 41"Street in Ames, Iowa as
related to the established FEMA Base Flood Elevation(BFE).Please refer to the Vicinity Map-
Exhibit A,enclosed.The current BFE at the proposed site is approximately 894.6t(all elevations in
this submittal reference NGVD 29).The proposed site is in the defined floodway of Squaw Creek.
Please refer to the FIRMette-Exhibit B.enclosed. The updated October 16,2014 FIRM panel
shows no change to the previous BFE.
The proposed communications monopole and support building shall be constructed in a heavily
wooded area at the northern limits of the floodway. Please refer to the Site Plan-Exhibit C,
enclosed.The site shall be cleared of 24 trees of varying maturity and trunk diameter.Please refer
to the Tree Removal Plan-Exhibit E,enclosed.The trees to be removed provide approximately
14.39 feet(width)of obstruction to flow. Existing grade at the proposed site is approximately 888.0.
The monopole is approximately 8 feet in diameter at the base.The support base for the building
including stairs and exterior walkway is 24 feet by 35.5 feet. Please refer to the Proposed
Building/Tower Elevation-Exhibit D,enclosed.The support building dimensions are 29.5 feet by 18
feet.The raised building base shall be oriented so that its narrowest dimension is perpendicular to
the flow of Squaw Creek.The flow direction of Squaw Creek is west to east at this site.The
monopole shall be placed at the west end of the building(upstream).The building shall be elevated
above the Base Flood Elevation by the use of reinforced concrete piers to the proposed finished
floor elevation is 898.0.Twelve,2-foot diameter piers and four, 1.33-foot diameter piers shall
elevate the proposed building. All electrical and mechanical support infrastructures for the building
and tower shall also be elevated above the BFE a minimum of 3 foot.
E&A Consulting Group, Inc.has obtained the latest hard copy of the Flood Insurance Study(FIS)
19169CV000B,dated October 16,2014,for Squaw Creek from its confluence with the Skunk River
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Proposed Verizon Tower Site
Ames,Iowa
Page 2 or 2
to its headwaters. The FIS data includes stream and water surface profiles used to interpret the
Base Flood Elevation at the site. No effective FIS hydraulic model was provided to E&A.
The proposed tower and building site is about 520 feet upstream of the former railroad
embankment (now recreational trail) and bridge over Squaw Creek. The nearest river sections
modeled in the FIS is at the former railroad embankment and near South 41'Street-A cross section
of the floodplain at River Station 9200 has total width of 3,700 feet that is below the Base Flood
Elevation at that station. The 24-foot width dimension of the raised base is 0.649 percent of 3,700
feet.
It is my opinion that the proposed Verizon Tower and building will cause no net rise in the Base
Flood Elevation. This conclusion is reached on the basis of several conditions. The site is in a
heavily wooded area that restricts flow velocity for that portion of the modeled cross section. The
wooded area is better at attenuating or storing the runoff than it is at conveying the runoff.Also,the
area of flow restriction due to the constructed reinforced concrete piers will be offset by the
removed trees.Another reason for concluding that this project will result in no net rise of the BFE is
that the encroachment length (24 feet) as compared to the overall length (3,700 feet) of the
modeled cross section is very small—less than 0.65%.The ground elevations around the building
perimeter will remain at the existing elevations and a negligible storage volume may be lost.
Another characteristic of this site is its spatial relation (upstream and off channel) to the former
railroad embankment and bridge. This railroad infrastructure creates an ineffective flow area
outside of the Squaw Creek channel bridge section.
Should you have any questions about this investigation and conclusion,please contact me at 402-
895-4700 or pgonzalestb�eacq cons.
Thank you for your time and consideration
Sincerely, `,�„attulouur�rr���
�ESSIp
E&A CONSULTING G UP y�Oaoa
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Attachment C: Structural Analysis Report
DECEIVE®
M, Y 13 2015
CITY OF AMES,IOWA
SSCDEPT OF PLANNING&HOUSING
STRUCTURAL ANALYSIS REPORT
Ven*zon Wireless
IA 10 Hetfield
255150
I;
May 12, 2014
i
SSC Inc.
9900 W 10911 S1,Suite 300,Overland Pork,KS 66210
Ph:(913)438-7100 Fax:(913)438-7777
scrv� solve corrrn-1u1-1icate
15
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OBJECTIVE
Design a steel platform and supporting structure for proposed Verizon Wireless shelter and
equipment at the new Verizon Wireless tower site.
CODES/REFERENCES
2012 IBC/ASCE 7-10/ACI 318/Geotechnical Report by Terracon(project#AB 125649.01)
dated 03-19-14/2014 Rev.B Drawings by SSC
ADDRESS
600 South Maple Street;Ames,Iowa 50010
SUMMARY
The conclusion of the following structural analysis is that the proposed IA10 Hetfield(255150)
structure is adequate for the proposed Verizon Wireless shelter and equipment shown by SSC
Rev.B drawings.
Appendix A-C will contain the following information:
Appendix A—RISA 3D Structural Analysis Report of Platform
• RISA 3D analysis of proposed steel platform
Appendix B—RISA 3D Structural Analysis Report of Piers
• RISA 3D analysis of proposed concrete piers
Appendix C—Foundation Structural Analysis Report
• Structural analysis of foundation supports of the proposed platform
I hereby certify that this engineering document was prepared by me
��., or under my direct pe sonal supervision and that I am a duly licensed
ofVs'Slo profess' nal E �gg�ie under the laws of the State of Iowa
' MICH(AEL L. i
AINENS jm = Michael L.Owens,P.E.to, date
>: tti247 :ate
R., My license renewal date is December 31, 2 0l S
low N � Pages or sheets covered by this seal:_.
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