Watsonville Municipal Code Art. 5 Provisions for Flood Hazard Reduction

In all special flood hazard areas the following standards are required:

(a) Anchoring:

(1) 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.

(2) All manufactured homes shall meet the anchoring standards of WMC Section 9-2.504.

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

(1) With flood resistant materials as specified in FEMA Technical Bulletin TB 2-93, and utility equipment resistant to flood damage.

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

(3) Have mechanical, plumbing, heating/cooling, ventilation, and electrical systems above the design flood elevation or meet the requirements of ASCE 24, except that minimum electric service required to address life safety and electric code requirements is permitted below the design flood elevation provided it conforms to the provisions of the electrical part of the building code for wet locations.

(4) If within Zones AH or AO, so that there are adequate drainage paths around structures on slopes to guide flood waters around and away from proposed structures.

(c) Elevation and floodproofing. (See Article 2 of this Chapter for definitions for “basement,” “lowest floor,” “new construction,” “substantial damage” and “substantial improvement.”

(1) Residential construction, new or substantial improvement, shall have the lowest floor of the entire structure, including basement,

(i) In an AO zone, one foot (1') above the base flood elevation, or elevated at least two feet (2') above the highest adjacent grade if no base flood elevation is specified.

(ii) In an A zone, one foot (1') above the base flood elevation; said base flood elevation shall be determined by one of the methods in WMC Subsection (b) of Section 9-2.402.

(iii) In all other Zones, one foot (1') above the base flood elevation. Upon the completion of the structure, the elevation of the lowest floor including basement shall be certified by a registered professional engineer or surveyor, and verified by the community building inspector to be properly elevated. Such certification and verification shall be provided to the Floodplain Administrator.

(2) Nonresidential construction, new or substantial improvement, shall either be elevated to conform with WMC Subsection (c)(1) of Section 9-2.500 or together with attendant utility and sanitary facilities;

(i) Be flood-proofed below the elevation recommended under WMC Subsection (c)(1) of Section 9-2.500 so that the structure is watertight with walls substantially impermeable to the passage of water;

(ii) Have structural components capable of resisting hydrostatic and hydrodynamic loads and effects of buoyancy; and

(iii) Be certified by a registered professional engineer or architect that the standards of WMC Subsection (c)(2) of Section 9-2.500 are satisfied. Such certification shall be provided to the Floodplain Administrator.

(3) All new construction and substantial improvement with fully enclosed areas 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 floodwater. Designs for meeting this requirement shall follow the guidelines in FEMA Technical Bulletins TB 1-93 and TB 7-93, and must meet or exceed the following minimum criteria:

(i) Have a minimum of two (2) openings having a total net area of not less than one (1) square inch for every square foot of enclosed area subject to flooding. The bottom of all openings shall be no higher than one foot (1') 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 floodwater; or

(ii) Be certified by a registered professional engineer or architect.

(4) Manufactured homes shall also meet the standards in WMC Section 9-2.504.

(§ 1, Ord. 1121-01 C-M, eff. January 10, 2002; as amended by § 1, Ord. 1422-21 CM, eff. November 11, 2021)

(a) All new and replacement water supply and sanitary sewage systems shall be designed to minimize or eliminate:

(1) Infiltration of flood waters into the systems; and

(2) Discharge from the systems into flood waters.

(b) On-site waste disposal systems shall be located to avoid impairment to them, or contamination from them during flooding.

(§ 1, Ord. 1121-01 C-M, eff. January 10, 2002)

(a) The storage or processing of materials which in time of flooding are buoyant, flammable, explosive, or could be injurious to human, animal, or plant life shall be prohibited.

(b) The storage of other materials or equipment may be allowed if not subject to major damage by floods and if firmly anchored to prevent flotation or if readily removable from the area within the time available after a flood warning.

(§ 1, Ord. 1121-01 C-M, eff. January 10, 2002)

(a) All tentative subdivision or parcel map proposals shall identify the special flood hazard area and the elevation of the base flood.

(b) All plans shall provide the elevation of proposed structure(s) and pad(s). If the site is filled above the base flood elevation, the lowest floor and pad elevations shall be certified by a registered professional engineer or surveyor and provided to the Floodplain Administrator.

(c) All proposals shall be consistent with the need to minimize flood damage.

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

(e) All proposals shall provide adequate drainage to reduce exposure to flood hazards.

(§ 1, Ord. 1121-01 C-M, eff. January 10, 2002)

All manufactured homes that are placed or substantially improved, within Zones A1-30, AH, and AE on the community’s Flood Insurance Rate Map, on sites located:

(1) Outside of a manufactured home park or subdivision;

(2) In a new manufactured home park or subdivision;

(3) In an expansion to an existing manufactured home park or subdivision; or

(4) In an existing manufactured home park or subdivision on a site upon which a manufactured home has incurred “substantial damage” as the result of a flood shall be elevated on a permanent foundation such that the lowest floor of the manufactured home is one foot (1') above the base flood elevation and be securely fastened to an adequately anchored foundation system to resist flotation, collapse, and lateral movement.

(b) All manufactured homes to be placed or substantially improved on sites in an existing manufactured home park or subdivision within Zones A1-30, AH and AE, on the community’s Flood Insurance Rate Map that are not subject to the provisions of WMC Subsection (a) of Section 9-2.504 shall be securely fastened to an adequately anchored foundation system to resist flotation, collapse, and lateral movement, and be elevated so that either the:

(1) Lowest floor of the manufactured home is one foot (1') above the base flood elevation; or

(2) Manufactured home chassis is supported by reinforced piers or other foundation elements of at least equivalent strength that are no less than thirty-six inches (36") in height above grade. If elevated on pilings, the lots shall be large enough for steps; the pilings shall be placed in stable soil no more than 10 feet (10') apart; reinforcement shall be provided for pilings more than six feet (6') above the ground surface; and calculations shall be provided for the bearing capacity.

(c) Certification of compliance shall be required of the developer or state agency responsible for the plan for regulating manufactured home placement. The elevation of the lowest floor shall be certified by a registered professional engineer or surveyor, and verified by the community building inspector to be properly elevated. Such certification and verification shall be provided to the Floodplain Administrator.

(d) No manufactured home shall be placed in a floodway, except in an existing manufactured home park or existing manufactured home subdivision.

(§ 1, Ord. 1121-01 C-M, eff. January 10, 2002)

Since floodways are an extremely hazardous area due to the velocity of floodwaters which carry debris, potential projectiles, and erosion potential, the following provisions apply:

(a) Until a regulatory floodway is adopted, no new construction, substantial development, or other development (including fill) shall be permitted within Zones A1-30 and AE, unless it is demonstrated that the cumulative effect of the proposed development, when combined with all other development, will not increase the water surface elevation of the base flood more than one foot at any point within the City of Watsonville.

(b) Within an adopted regulatory floodway, the City of Watsonville shall prohibit encroachments, including new fill, new construction, substantial improvements, and other development, unless certification by a registered civil engineer is provided demonstrating that the proposed encroachment shall not result in any increase in flood levels during occurrence of the base flood discharge.

If provisions of Subsections (a) and (b), above are satisfied, all new construction, substantial improvement, and other proposed new development shall comply with all other applicable flood hazard reduction provisions of Section 9-2.05 of this Chapter.

(§ 1, Ord. 1204-06 C-M, eff. November 23, 2006)

All recreational vehicles placed in Zones A1-30, AH, and AE will either:

(a) Be on site for fewer than thirty (30) consecutive days, in accordance with Section 11-1.21 of this Code; or

(b) Be fully licensed and ready for highway use. A recreational vehicle is ready for highway use if it is on its wheels or jacking system, is attached to the site only by quick disconnect type utilities and security devices, and has no permanently attached additions.

(§ 1, Ord. 1204-06 C-M, eff. November 23, 2006)