Plumas County Municipal Code Art. 3 Provisions for Flood Hazard Reduction

The following standards of construction apply, as appropriate, for any man-made change to real estate in an area of special flood hazard for which a development permit is issued, including the installation of manufactured homes:

(a) Anchoring. All new construction and substantial improvements shall be adequately anchored to prevent flotation, collapse or lateral movement of the structure resulting from hydrodynamic and hydrostatic loads, including the effects of buoyancy.

(b) Construction materials and methods. All new construction and substantial improvement shall be constructed:

(1) With materials and utility equipment resistant to flood damage;

(2) Using methods and practices that minimize flood damage;

(3) With electrical, heating, ventilation, plumbing and air conditioning equipment and other service facilities that are designed or located so as to prevent water from entering or accumulating within the components during conditions of flooding; and

(4) Within zones AH or AO, so that there are adequate drainage paths around structures on slopes to guide floodwaters around and away from proposed structures.

(c) Elevation and floodproofing:

(1) In an A zone, residential construction, new or substantial improvement, shall have the lowest floor, including basement, elevated at least one foot above the base flood elevation. In an AO zone, residential construction, new or substantial improvement, shall have the lowest floor, including basement, elevated above the highest adjacent grade to a height exceeding the depth number specified in feet on the Flood Insurance Rate Map by at least one foot, or elevated at least three (3') feet above the highest adjacent grade if no depth number is specified. On completion of the structure, the elevation of the lowest floor shall be certified by a registered professional engineer or surveyor, and shall be verified by the Building Official, to be properly elevated. The certification and verification shall be provided to the Building Official and the County Engineer.

(2) Non-residential construction, new or substantial improvement shall be certified by a registered professional engineer or architect as meeting the following standards, which certification shall be provided to the Building Official and the County Engineer. Non-residential new construction or substantial improvement:

(i) shall have the lowest floor elevated at least one foot above the base flood elevation; or

(ii) together with attendant utility and sanitary facilities, shall be floodproofed below the base flood elevation so that the structure is watertight with walls substantially impermeable to the passage of water; and

(iii) together with attendant utility and sanitary facilities, shall have structural components capable of resisting hydrostatic and hydrodynamic loads and effects of buoyancy;

(3) All new construction and substantial improvement with fully enclosed area below the lowest floor, excluding basements, that are usable solely for parking of vehicles, building access or storage, 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 flood water. Designs for meeting this requirement must exceed the following minimum criteria:

(i) they must be certified by a registered professional engineer or architect that they comply with Federal Emergency Management Agency Technical Bulletin 1-93 under the guidelines for engineered openings;

(ii) they must have a minimum of two (2) openings having a total net area of not less than one square inch for every square foot of enclosed area subject to flooding. 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 that they permit the automatic entry and exit of flood water; or

(iii) they must be determined to comply with local flood proofing standards approved by the Federal Insurance Administration, Federal Emergency Management Agency.

(§ 1 (Exh. A), Ord. 98-902, eff. September 10, 1998, as amended by § 3 (Exh. A), Ord. 01-961, eff. December 20, 2001)

The following standards apply, as appropriate, for any man-made change to real estate in an area of special flood hazard for which a development permit is issued.

(a) All new and replacement water supply systems shall be designed to minimize or eliminate infiltration of flood waters into the system.

(b) All new and replacement sanitary sewage systems shall be designed to minimize or eliminate infiltration of flood waters into the system and discharge from the system into flood waters.

(c) Onsite waste disposal systems shall be located to minimize impairment to them or contamination from them during flooding.

(§ 1 (Exh. A), Ord. 98-902, eff. September 10, 1998)

The following standards apply, as appropriate, for any man-made change to real estate in an area of special flood hazard for which a development permit is issued.

(a) Encroachment in a floodway shall be prohibited unless certification by a registered professional engineer or architect is provided demonstrating that the encroachment shall not result in any increase in the base flood elevation during the occurrence of the base flood discharge; and

(b) If such certification is provided, man-made changes to real estate shall comply with the provisions of this article.

(§ 1 (Exh. A), Ord. 98-902, eff. September 10, 1998)

The following standards apply, as appropriate, for any man-made change to real estate in an area of special flood hazard for which a development permit is issued.

(a) Encroachment in areas where base flood elevations have been determined but a floodway has not been designated shall be prohibited unless certification by a registered professional engineer or architect is provided demonstrating that the encroachment shall not result in a cumulative effect when combined with all other existing and anticipated man-made changes to real estate that will increase the water surface elevation of the base flood more than one foot at any point; and

(b) If such certification is provided, man-made changes to real estate shall comply with the provisions of this article.

(§ 1 (Exh. A), Ord. 98-902, eff. September 10, 1998)