ARTICLE X. FLOODWAY FRINGE

SECTION 10.1. FLOODPLAIN USE PERMIT

All new uses and substantial improvements to existing structures within a Floodway Fringe (A1-30 and AE Zones) specified in 10.1.1 through 10.1.6 below require a Floodplain Use Permit issued by the Floodplain Administrator subject to the provisions of Section 10.2. Issuance of a Floodplain Use Permit does not exempt the holder of the Floodplain Use Permit from any additional requirements necessary to obtain flood insurance. Uses for which a Floodplain Use Permit may be granted are:

1.  Any use permitted in Section 9.1.

2.  Structures and buildings, including dwellings and mobile/manufactured homes, recreational vehicles and other residential uses.

3.  New and replacement water supply systems, water treatment and sewage collection and disposal systems provided that they are designed to prevent or minimize floodwater contamination during the base flood.

4.  New and replacement sanitary sewage systems, provided that they are designed to minimize or eliminate infiltration of flood waters into the systems and discharges from the systems into flood waters, unless otherwise allowed by a permit in conformance with the Federal Water Pollution Control Act.

5.  Septic systems and solid waste landfills, whether public or privately owned, provided that they are located in such a way as to avoid impairment to them or contamination from them during flooding and provided that no part of a solid waste landfill is within one-half mile of a one-hundred year floodplain that has one-hundred year flows in excess of twenty-five thousand cubic feet per second as determined by the Federal Emergency Management Agency.

6.  Any other uses which will not be subject to substantial flood damage and which will not cause a hazard to life or property or to the public. These may include uses which can be readily removed from delineated floodplain areas during times of flooding.

SECTION 10.2. FLOODWAY FRINGE DEVELOPMENT STANDARDS

1.  New construction or substantial improvement to any existing structure shall be constructed with methods which minimize flood damage with materials and utilities resistant to flood damage.

2.  In order to control erosion and preserve the natural and beneficial functions of the floodplain, removal of vegetation shall be the minimum necessary for the development.

3.  Erosion setbacks shall meet applicable Arizona State Standards or as determined by the Floodplain Administrator.

4.  Dwellings other than mobile/manufactured homes shall have the lowest floor elevated and all utilities elevated or floodproofed up to or above the Regulatory Flood Elevation. The applicant shall provide an Elevation/Floodproofing Certificate by an Arizona Registered Professional Engineer or Land Surveyor certifying that the elevation or floodproofing requirement has been met.

5.  Mobile/manufactured homes including permanently placed recreation vehicles shall be elevated so that the bottom of the structural frame is at or above the Regulatory Flood Elevation and is anchored to prevent floatation, collapse or movement. Methods of anchoring may include, but not be limited to, use of over-the-top or frame ties to ground or foundation anchors. Specific requirements shall be as follows:

a.  Over-the-top or frame ties shall be provided at each of the four corners of the mobile/manufactured home, with additional ties on each side at intermediate locations;

b.  Mobile/manufactured homes more than 50 feet long require one additional tie per side;

c.  All components of the anchoring system shall be capable of carrying a force of 4,800 pounds;

d.  Adequate surface drainage and access for a hauler are provided;

e.  In the instance of elevating on piers, setbacks are sufficient to permit steps, pier foundations are placed in stable soil no more than ten feet part, and reinforcement is provided for piers more than six feet above ground level. A scour analysis may be required when elevating on piers;

f.  Any additions to the mobile/manufactured home must be similarly anchored; and

g.  Attached appliances and all utilities shall be either elevated or floodproofed up to the Regulatory Flood Elevation.

h.  The above requirements do not apply to units in storage, and may be waived by the Floodplain Administrator on a case by case basis for units placed for less than 180 consecutive days, which are properly licensed and ready for highway use, or are on jacks or wheels with quick disconnect of utilities and have no permanently attached additions.

6.  For all mobile/manufactured home parks and mobile/manufactured home subdivisions an evacuation plan indicating alternate vehicular access and escape routes shall be filed with the Pinal County Office of Emergency Management.

7.  Fill material, if used to elevate structures, shall meet all of the following standards:

a.  The top of such fill material shall be at no point lower than the Regulatory Flood Elevation.

b.  Such fill material shall extend at least 25 feet beyond the walls or supporting frame of the structure, or as approved by the Floodplain Administrator.

c.  Fill material shall be placed and compacted in accordance with the applicable building code.

d.  Fill material shall not interfere with local drainage or tributary flow of the channel of any watercourse.

e.  Fill material proposed in excess of the amount and extent required herein shall be shown by the applicant to have no detrimental effect on the purposes of this Regulation and the amount of fill material shall not be greater than is necessary to achieve the purpose for which it is intended as demonstrated by a plan submitted by the applicant indicating the uses to which the filled land will be put and the final dimensions and extent of the proposed fill material.

8.  Fill material for purposes other than solid waste landfills shall not include junk, trash, tires, garbage, wood or other buoyant materials nor hazardous, toxic or deleterious material and shall be protected as needed against scour and erosion by riprap or other protective measures as approved by the Floodplain Administrator.

9.  Permitted landfills shall be protected against scour, erosion and contamination by and contamination of the 100-year flood event.

10. Buildings, except dwellings or any type of residence may have the lowest floor below the Regulatory Flood Elevation provided that they shall be watertight with walls substantially impermeable to the passage of water and structural components and utilities having the capacity of resisting the effects associated with a base flood. Designs for meeting this criteria shall either be certified on a Floodproofing Certificate by an Arizona Registered Professional Engineer or the design must meet or exceed the following minimum criteria: A minimum of two openings, on at least two sides, having a total net area of not less than one square inch for every square foot of enclosed area subject to flooding shall be provided. The bottom of all openings shall be no higher than one foot above grade. Openings may be equipped with screens, louvers, valves, or other coverings or devices provided they allow the automatic entry and exit of floodwaters.

11.  All new construction and substantial improvements that fully enclose areas below the lowest floor that are usable solely for parking of vehicles, building access or storage in an area other than a basement, and which are subject to flooding, shall be designed to automatically equalize hydrostatic flood forces on exterior walls by allowing for the entry and exit of floodwaters. The applicant shall provide a Floodproofing Certificate by an Arizona Registered Professional Engineer certifying that the floodproofing requirements have been met, or the design shall meet the provisions of Section 10.2.10

12.  Sand and Gravel Extraction.

A Floodplain Use Permit for the extraction of sand and gravel or other materials within the floodway fringe shall be granted if the applicant shows that excavations shall not have a cumulative adverse impact nor be of such depth, width, length, or location as to present a hazard to life or property or to the watercourse in which they are located and comply with any applicable Watercourse Master Plan adopted by the Board of Directors subject to the following conditions:

a.  Unprotected excavations shall not be permitted so close to any floodplain crossings, utility structures or facilities as to cause or have the potential to cause an adverse effect on such crossings, utilities or similar facilities.

b.  No stockpiling of tailings, overburden or sand and gravel which may obstruct, divert or retard the natural flow of tributaries to the main watercourse except as specifically approved by the Floodplain Administrator in a particular Floodplain Use Permit shall be permitted.

c.  Dikes or levees are permitted provided it can be shown by the applicant that such dikes or levees shall not adversely effect structures, road or utility crossings, other public or private property, shall not cause erosion or diversion of flood flows onto property outside the delineated floodplain, and shall not create a danger to life or property.

d.  The plan of development shall include a plan of reclamation to leave the land when the approved use is terminated in such a condition as to maintain stability of the delineated floodplain or to an improved condition to enhance higher use of the land.

e.  A plan of development shall be submitted with an application for a Floodplain Use Permit to the Floodplain Administrator. The Floodplain Administrator shall determine whether an engineered plan shall be required and whether a sediment transport analysis is necessary.

f.  Any significant change, as determined by the Floodplain Administrator, in a previously approved plan of development shall require an application to amend the approved plan of development.

g.  In order to control erosion and preserve the natural and beneficial functions of the floodplain, removal of vegetation shall be the minimum necessary for development.

h.  The plan of development is subject to post-flood review and possible modification if necessary due to flood related changes in river morphology.

i.  Erosion setbacks shall meet Arizona State Standards or as approved by the Floodplain Administrator.