Pinole Municipal Code Art. V Provisions for Flood Hazard Reduction

In all areas of special flood hazards the following standards are required:

A. Anchoring.

1. All new construction and substantial improvement shall be anchored to prevent flotation, collapse or lateral movement of the structure resulting from hydrodynamic and hydrostatic loads, including the effects of buoyancy.

2. All manufactured homes shall meet the anchoring standards of Section 15.48.200.

B. Construction Materials and Methods.

1. All new construction and substantial improvements shall be constructed with materials and utility equipment resistant to flood damage.

2. All new construction and substantial improvements shall be constructed using methods and practices that minimize flood damage.

3. All new construction and substantial improvements shall be constructed with electrical, heating, ventilation, plumbing and air conditioning equipment and other service facilities that are designed and/or located so as to prevent water from entering or accumulating within the components during conditions of flooding.

C. Elevation and Floodproofing.

1. New construction and substantial improvement of any structure shall have the lowest floor, including basement, elevated to or above the base flood elevation. Nonresidential structures may meet the standards in Section 15.48.170(C)(2). Upon the completion of the structure the elevation of the lowest floor including basement shall be certified by a registered professional engineer or surveyor, or verified by the community building inspector to be properly elevated. Such certification or verification shall be provided to the Floodplain Administrator.

2. Nonresidential construction shall either be elevated in conformance with Section 15.48.170 (C) (1) or together with attendant utility and sanitary facilities:

a. Be floodproofed so that below the base flood level the structure is watertight with walls substantially impermeable to the passage of water;

b. Have structural components capable of resisting hydrostatic and hydrodynamic loads and effects of buoyancy;

c. Be certified by a registered professional engineer or architect that the standards of this subsection are satisfied. Such certifications shall be provided to the Floodplain Administrator.

3. Require, for all new construction and substantial improvements, that fully enclosed areas below the lowest floor that 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. Designs for meeting this requirement must either be certified by a registered professional engineer-or architect or meet or exceed the following minimum criteria:

a. Either a minimum of two openings 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 that they permit the automatic entry and exit of floodwaters;

b. Be certified to comply with a local floodproofing standard approved by the Federal Insurance Administration.

4. Manufactured homes' shall also meet the standards in Section 15.48.200. (Ord. 2009-02 § 6, 2009; Ord. 511 § 2(Exh. A) (part), 1988).

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

B. On-site waste disposal systems shall be located to avoid impairment to them or contamination from them during flooding. (Ord. 511 § 2(Exh. A) (part), 1988).

A. All preliminary subdivision proposals and other proposed development, including proposals for manufactured home parks and subdivisions, greater than fifty (50) lots or five (5) acres, whichever is the lesser, shall identify the special flood hazard area and the elevation of the base flood.

B. All final subdivision plans will provide the elevation of the lowest floors of all proposed structure(s) and pads. If the site is filled above the base flood, the final pad elevation shall be certified by a registered professional engineer or surveyor and provided to the Floodplain Administrator.

C. All subdivision proposals shall be consistent with the need to minimize flood damage.

D. All subdivision proposals shall have public utilities and facilities such as sewer, gas, electrical and water systems located and constructed to minimize flood damage.

E. All subdivisions shall provide adequate drainage to reduce exposure to flood hazards.

F. If the site is filled above the base flood elevation, the following as-built information for each structure shall be certified by a registered civil engineer or licensed land surveyor and provided as part of an application for a Letter of Map Revision based on Fill (LOMR-F) to the Floodplain Administrator:

• 1. Lowest floor elevation.
• 2. Pad elevation.
• 3. Lowest adjacent grade.

(Ord. 2009-02 § 7, 2009; Ord. 511 § 2(Exh. A) (part), 1988).

All new and replacement manufactured homes and additions to manufactured homes shall:

A. Be elevated so that the lowest floor is at or above the base flood elevation.

B. Be securely anchored to a permanent foundation system to resist flotation, collapse or lateral movement. (Ord. 511 § 2 (Exh. A) (part), 1988).

Located within areas of special flood hazard established in Section 15.48.080 are areas designated as floodways. Since the floodway is an extremely hazardous area due to the velocity of floodwaters which carry debris, potential projectiles, and erosion potential, the following provisions apply:

A. Prohibit encroachments, including fill, new construction, substantial improvements, and other development unless certification by a registered professional engineer or architect is provided demonstrating that encroachments shall not result in any increase in flood levels during the occurrence of the base flood discharge.

B. If subsection A of this section is satisfied, all new construction and substantial improvements shall comply with all other applicable flood hazard reduction provisions of this article. (Ord. 511 § 2(Exh. A) (part), 1988).

Within coastal high hazard areas established in Section 15.48.080, the following standards shall apply:

A. All new construction and substantial improvements shall be elevated on adequately anchored pilings or columns and securely anchored to such pilings or columns so that the lowest horizontal portion of the structural members of the lowest floor (excluding the pilings or columns) is elevated to or above the base flood elevation.

B. All new construction shall be located on the landward side of the rear of mean high tide.

C. All new construction and substantial improvements shall have the space below the lowest floor free of obstructions or constructed with breakaway walls. Such temporarily enclosed space shall not be used for human habitation.

D. Fill shall not be used for structural support of buildings.

E. Manmade alteration of sand dunes which would increase potential flood damage is prohibited.

F. The floodplain administrator shall obtain and maintain the following records:

1. Certification by a registered engineer or architect that a proposed structure complies with Section 15.48.080(A).

2. The elevation (in relation to mean sea level) of the bottom of the lowest structural member of the lowest floor (excluding pilings or columns) of all new and substantially improved structures, and whether such structures contain a basement. (Ord. 511 §2(Exh. A) (part), 1988).