HomeMy WebLinkAboutStaff Report (Ilirifill111114
CITY OF COLLEGE STATION
VARIANCE REQUEST
FOR
FLOODWAY ENCROACHMENT
REQUEST: Floodway Variance from Section G(1) of the Flood Protection
Ordinance prohibiting encroachment into FEMA designated
floodways. Specifically locating box culverts in the
floodplain/floodway to allow for the crossing of these portions of
the creek.
LOCATION: 1300 Harvey Mitchell Parkway
2818 Place Properties, Lots 1 & 2, Block 1
APPLICANT: Chris Harris, P.E.
PROPERTY OWNER: Place Properties c/o Ryan Griffis
PROJECT MANAGER: Joshua D. Norton, P.E, Assistant City Engineer
jnorton@cstx.gov
RECOMMENDATION: Staff recommends approval.
BACKGROUND: To participate in the National Flood Insurance Program so that our citizens
can have subsidized flood insurance, the City has adopted the Flood Protection Ordinance in
accordance the associated Code of Federal Regulations for FEMA. The City has opted to
increase the regulations in regard to floodway encroachments. The minimum federal
requirements state that encroachments into the floodway are permissible with a zero rise study.
The City's regulations require a variance with the attached criteria as well.
The federal code generally defines the "floodway" as the channel of a river or other watercourse
and the adjacent land areas that must be reserved in order to discharge the base flood without
cumulatively increasing the water surface elevation more than a designated height (one foot).
The box culverts clearly encroach into the associated floodway. The applicant has addressed
each of the criteria as well as provided a drainage analysis which depicts the water surface will
not increase above the allowable floodway elevation.
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Zoning Board of Adjustment Page 1 of 6
August 5,2008
APPLICABLE ORDINANCE SECTION: Chapter 13, Section 5.G - Special Provisions for
Floodways
G. SPECIAL PROVISIONS FOR FLOODWAYS
Located within Areas of Special Flood Hazard established in Section 5-B are areas
designated as floodways. The floodway is an extremely hazardous area due to the
velocity of flood waters which carry debris, potential projectiles, and the potential for
erosion; therefore, the following provisions shall be required:
(1) Encroachments shall be prohibited, including fill, new construction, substantial
improvements of existing construction, structures, manufactured homes, or other
development. Variances requested on this standard shall be accompanied by a
complete engineering report fully demonstrating that the encroachments shall not
result in any increase in water surface elevation or flood hazard upstream, within, or
downstream of the encroachment location. The engineering report shall conform to
the requirements of the Drainage Policy and Design Standards and shall bear the
dated seal and signature of a registered professional engineer;
ORDINANCE INTENT: Chapter 13, Section B states: "It is the purpose of this chapter to
protect, maintain, and enhance the public health, safety, and general welfare by establishing
minimum requirements and procedures to control the adverse impacts associated with the
increased storm water flows generated by development. It is also the purpose of this chapter to
enhance the public health, safety and welfare by furthering the goals and objectives of the City
of College Station Comprehensive Plan and all of its elements."
Unmitigated encroachments into designated floodways are known to cause increases in flood
levels and the potential for damage from flooding events. As such they are specifically
prohibited.
It is clearly the intent of the Ordinance to prohibit encroachments into the areas reserved for
flood waters. It does not appear that the intent was to prohibit encroachment into areas that
may be above a reasonable flood event, even though the encroachment would be within the
regulatory limits of the floodway.
Zoning Board of Adjustment Page 2 of 6
August 5,2008
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August 5,2008
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Zoning Board of Adjustment Page 4 of 6
August 5,2008
NOTIFICATIONS
Advertised Board Hearing Date: August 5, 2008.
The following neighborhood organizations that are registered with the City of College Station's
Neighborhood Services have received a courtesy letter of notification of this public hearing:
None
Property owner notices mailed: 6
Contacts in support: 0
Contacts in opposition: 0
Inquiry contacts: 2
ZONING AND LAND USES
Direction Zoning Land Use
R-4 Multifamily, and Developing as Apartments, and
Subject Property
A-O Agricultural Open Floodplain /Streams
North - Harvey Mitchell Parkway
South CU College & University Vacant
East A-O Agricultural Open Vacant
West A-O Vacant
PHYSICAL CHARACTERISTICS
1. Frontage: This property has frontage along FM 2818 (Freeway)
2. Access: This property takes access to FM 2818 (Freeway).
3. Topography and vegetation: The site is divided into 2 Lots or 2 Phases. Lot 1 or Phase 1
is currently being developed as an apartment complex. Lot 2 or Phase 2 is largely
undeveloped and in its natural state with many mature oak trees though primarily cleared
underbrush. The site is traversed by an unnamed tributary of Whites Creek. Drainage runs
off the site by way of the unnamed tributary which then flows in a southwesterly direction.
4. Floodplain: Special Flood Hazard Area as defined by FEMA is present on the subject site
with both base flood elevations and floodway designations (FEMA FIRM Panel 182c).
REVIEW CRITERIA
Special Conditions and Hardships: The applicant's engineer has stated that without the
culvert crossing, the owner would not be able to access half of the property there by denying
him reasonable use of his land. The two crossings are required in order to provide adequate
fire protection for the residents of the property. The variance meets all of the following
prerequisites as outlined in the City's Flood Hazard Protection Ordinance.
Zoning Board of Adjustment Page 5 of 6
August 5,2008
Minimum Relief Necessary: The variance that the applicant is requesting, i.e. to install box
culverts or crossings, within the floodway, is the minimum relief necessary.
Health, Safety and Welfare: This variance will not be detrimental to the public health, safety
or welfare or injurious to other property in the City. This is the minimum impact necessary to
maintain the health, safety, and welfare of the residents and provide the owner with reasonable
use of the land. As evidenced by the engineering report, a .01' rise in water surface elevation
does occur but occurs wholly on the applicant's property and only in the vicinity of the proposed
box culvert. Per correspondence with FEMA, anything less than .02' can be interpreted by the
local floodplain administrator as a "zero rise."
No Negative Impacts: As evidenced by the engineering report and FEMA's input, there will be
NO increase in base flood elevation or alter any drainage pathways. The proposed box culverts
have been sized appropriately and do not decrease the cross sectional area in these two
locations. The crossings will not increase the water surface elevations, flow velocities, or alter
drainage pathways to the extent that there will be any threat to public safety, extraordinary
public expense, increase in flooding, or be detrimental to other portions of the drainage system.
Orderly Subdivision of Land: These crossings will not impact the subdivision of land
upstream or downstream of the property.
Zero Rise: Although the submitted engineering report illustrates a .01' rise in the water surface
elevation, FEMA has confirmed that .02' and less can be determined by the local floodplain
administrator as a zero rise. Therefore the crossings will not increase water surface elevations
below, within, or above the crossings location during the base flood discharge.
Summary and Flood Proofing: All other structures are located outside of the floodplain and
will not be impacted by the base flood. The road elevation of the crossings are above the base
flood elevation and will not be impacted by the base flood or create a threat to public safety.
The applicant's engineer believes that they have met the criteria as outlined in this section.
ALTERNATIVES: Not construct the subject improvements.
STAFF RECOMMENDATION: Staff recommends approval.
SUPPORTING MATERIALS
1. Application
2. Site Plan (provided in packet)
Zoning Board of Adjustment Page 6 of 6
August 5,2008