17-5-8 Floodway Fringe Area Requirements.
A. Floodway fringe areas shall be subject to the following regulations:
1. The following uses shall be permitted within a floodway fringe area to the extent that they are not prohibited by any other ordinance, and only upon issuance of a floodplain use permit:
a. Any use permitted in Section 17-5-7, Floodways;
b. Any other use not involving structures, provided it is elevated above the regulatory base flood elevation and a determination is made by the Town Engineer that the use will not increase the base flood elevation more than one (1) foot where the owner of the land doing the development owns both sides of the floodway, and not more than one-tenth (0.1) foot where only one (1) side is owned. In no case shall the development increase the water surface elevation more than one-tenth (0.1) foot on the property owned by others upstream and downstream, nor unduly restrict the capacity of the channels or floodway of tributaries to the main stream or watercourse, drainage ditches, or other drainage facilities or systems. The aforementioned water surface elevation increases apply to all watercourse channels in Oro Valley except the Canada del Oro Wash where the elevation of the existing levee system and bank protection will allow for no water surface elevation increases due to encroachment. Additionally, when main channel floodflow velocities are greater than four (4) feet per second (fps), a land use/development activity shall not increase floodflow velocities immediately downstream of the activity by more than one (1) fps or ten percent (10%), whichever is less, in the regulatory floodway. Any velocity increase greater than the aforementioned criteria must be reviewed and approved by the Town Engineer;
c. Structures, including dwellings, may be erected or moved, provided the lowest floor or basement floor is placed at or above the regulatory flood elevation. Land may be filled; provided, that the top of such fill shall be at or above the regulatory flood elevation for the particular area, and unless structurally protected from erosion shall extend at such elevations at least twenty-five (25) feet beyond the limits of any structure erected or placed thereon. Where structural protection from erosion is provided, the minimum extent to which tops of the fill pad must extend shall not be less than fifteen (15) feet. The placement of structures and any accompanying fill shall not affect base flood elevation beyond the limits set in subsection (A)(1)(b) of this section.
B. The following minimum requirements apply to all uses located within a regulatory floodplain:
1. All new construction (including prefabricated structures and mobile homes) and substantial improvements shall be anchored to prevent flotation and lateral movement, and be constructed with flood resistant materials and methods.
2. All proposed plats and proposals for other developments, including their utilities, streets, and drainage structures, shall be located and designed to be consistent with the need to minimize flood damage.
3. All tentative development plans, site plans, final site plans, improvement plans, and final plats, and other proposed new developments shall include base flood elevation data or as otherwise directed by the Town Engineer.
4. If in a riverine situation, all adjacent communities and the State Coordinating Office must be notified prior to any alteration or relocation of the watercourse, and copies of such notifications must be sent to the FEMA. Within the proposed altered or relocated portion of any watercourse, the flood carrying capacity shall be maintained.
5. Within one hundred twenty (120) days after completion of construction of any flood control protective works which changes the rate of flow during the flood, or changes the configuration of the floodplain, the person or agency responsible for installation of the protective works shall provide to the governing bodies of all jurisdictions affected by the protective works a new delineation of all floodplains affected. The new floodplain delineation shall be done according to the criteria adopted by the State of Arizona Director of Water Resources.
C. Limitations.
1. No use shall be allowed within a floodway fringe which:
a. Acting alone or in combination with existing or future uses creates danger or hazard to life or property;
b. Increases the water surface elevation for the base flood by more than that allowed under subsection (A)(1)(b) of this section;
c. Adversely affects groundwater recharge.
D. Critical Facilities.
1. “Critical facility” means any of the following:
a. A structure or facility that produces, uses or stores highly volatile, flammable, explosive, toxic, and/or water-reactive materials;
b. Hospitals, emergency medical facilities, nursing homes and/or housing facilities likely to have occupants who may not be sufficiently mobile to avoid injury or death during a flood;
c. Essential emergency response facilities, such as police stations, fire stations, emergency shelters and/or operation centers that are needed for public safety and/or flood response activities before, during and after a flood; and
d. Public and private utility facilities, such as but not limited to power, water and wastewater treatment, and/or communications, that are vital to maintaining or restoring normal services to flooded areas before, during and after a flood.
2. Applicability. The critical facility requirements shall only apply along watercourses which have FEMA designated floodplains. Where the two-tenths percent (0.2%) chance floodplain has not been established, the Town Engineer may require that this floodplain be delineated by the applicant.
3. Critical facilities shall be located outside of the two-tenths percent (0.2%) annual chance (five hundred (500) year) floodplain, if possible. If a critical facility must be located in a two-tenths percent (0.2%) annual chance (five hundred (500) year) floodplain, it must be demonstrated that there is either a critical need to locate it within the floodplain, or that there is not a suitable alternative site, as justified by an Arizona registered professional engineer. Any critical facility located within a two-tenths percent (0.2%) annual chance (five hundred (500) year) floodplain shall be protected from that event. “Protection” includes, but is not limited to, elevating the lowest floor and all utilities and mechanical services to a minimum of one (1) foot above the base flood or to the two-tenths percent (0.2%) annual chance (five hundred (500) year) floodplain water surface elevation, whichever is greater, providing elevated access ramps, if appropriate, adequately protecting the facility from both lateral and vertical erosion associated with the two-tenths percent (0.2%) annual chance (five hundred (500) year) floodplain, providing all weather access during the base flood and developing an emergency response plan.
4. Existing critical facilities within the two-tenths percent (0.2%) annual chance (five hundred (500) year) floodplain that propose substantial improvements and/or repairs shall be protected from the two-tenths percent (0.2%) annual chance (five hundred (500) year) flood event. “Protection” includes, but is not limited to, elevating or flood-proofing the lowest floor and all utilities and mechanical services to a minimum of one (1) foot above the base flood or to the two-tenths percent (0.2%) annual chance (five hundred (500) year) floodplain water surface elevation, whichever is greater, providing elevated access ramps, if appropriate, adequately protecting the facility from both lateral and vertical erosion associated with the two-tenths percent (0.2%) annual chance (five hundred (500) year) floodplain, providing all-weather access to the base flood and developing an emergency response plan. ((O)21-06, 11/17/2021; (O)17-04, 04/05/2017; (O)05-35, 10/05/2005)