Flood zone construction and development rules

Flood Fringe. The flood fringe areas are identified on the FIRMs as AE, AO, and AH zones.Anchoring. All new construction, repetitive loss structures, and substantial improvements shall be anchored to prevent flotation, collapse or lateral movement of the structure.Construction Materials and Methods.All new construction, repetitive loss structures, and substantial improvements shall be constructed with materials and utility equipment resistant to flood damage.All new construction, repetitive loss structures, and substantial improvements shall be constructed using methods and practices that minimize flood damage.All electrical, heating, ventilation, plumbing, and air-conditioning equipment and other service facilities shall be designed and/or located so as to prevent water from entering or accumulating within the components during the conditions of flooding.Elevation and Floodproofing.Residential Structures. All new construction, repetitive loss structures, and substantial improvements of residential structures within Al-30, AE, AO, and AH zones on the community's FIRM shall have the lowest floor (including basements) elevated to or above the base flood level. Fully enclosed areas below the lowest floor that are useable 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.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 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 shall be provided. The bottom of all openings shall be no higher than one (1) 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.Nonresidential Structures. All new construction, repetitive loss structures, and substantial improvements of nonresidential structures shall either:Elevate the lowest floor, including basement, to or above the base flood elevation; orTogether with attendant utility and sanitary facilities be floodproofed so that below the base flood level the structure is watertight with walls substantially impermeable to the passage of water and have structural components capable of resisting hydrostatic and hydrodynamic loads and effects of buoyancy.All manufactured homes must be installed on a permanent foundation and the lowest floors shall be elevated to or above the base flood elevation plus one (1) foot. Manufactured homes shall comply with the anchoring, construction materials and methods, machinery and equipment requirements of this Section and fully enclosed areas below the lowest floor shall be useable solely for parking of vehicles, building access, or storage and shall comply with the applicable provisions in this Section for flood openings.No machinery or equipment which service a building such as furnaces, air conditioners, heat pumps, hot water heaters, washers, dryers, elevator lift equipment, electrical junction and circuit breaker boxes, and food freezers, are permitted below the base flood elevation; and all interior wall, floor and ceiling materials located below the base flood elevation must be unfinished and resistant to flood damage; and the walls of any enclosed area below the base flood elevation must be constructed in a manner to prevent flotation, collapse, lateral movement of the structure.Building Height. Notwithstanding the maximum building height limitations as stated in overall building and wall plate height, provided in Paragraph 8-4.5(b) for single-family detached and attached residential dwellings under the Comprehensive Zoning Ordinance and Paragraph 10-2.4(e)(1) for all structures under the North Shore Development Plan Ordinance, the maximum building height in the flood fringe area shall be as follows:Within the North Shore Planning Area. No structure shall be higher than twenty-five (25) feet from ground level or the base flood elevation plus fifteen (15) feet, whichever is greater at the site, unless a greater height is authorized by the Planning Commission pursuant to a use permit after review and recommendation by the North Shore Improvement Committee.Single-Family Dwellings Outside the North Shore Special Planning Area. No singlefamily detached and attached dwellings outside the North Shore special planning area shall be higher than thirty (30) feet from ground or the base flood elevation plus fifteen (15) feet, whichever is greater at the site unless otherwise permitted by the Planning Commission.Water and Sewer.All new and replacement water supply and sanitary sewage systems shall be designed to minimize or eliminate infiltration of floodwaters into the system and discharge from systems into floodwaters.On-site waste disposal systems shall be located to avoid impairment to them or contamination from them during flooding.Certification by Engineer or Architect. Building plans for new construction, repetitive loss structures, and substantial improvements shall be certified by a registered professional structural engineer or architect that the new construction is designed in compliance with the requirements of this Section. For nonresidential buildings that are dry floodproofed in accordance with this Section, the certification shall state that the design and methods of construction are in accordance with accepted standards of practice for meeting those requirements. Prior to the issuance of the certificate of occupancy, the elevation of the lowest floor shall be certified by a registered professional civil engineer or surveyor.All new construction, repetitive loss structures, and substantial improvements shall be designed (or modified) and adequately anchored to prevent flotation, collapse, or lateral movement of the structure resulting from hydrodynamic and hydrostatic loads, including the effects of buoyancy, be constructed with materials resistant to flood damages and be constructed by methods and practices that minimize flood damages.In AE zones along watercourses where no floodway has been designated, no new construction, repetitive loss structures, substantial improvements, or other development (including fill) shall be permitted in the AE zone on the community's FIRM, unless it is demonstrated that the cumulative effect of the proposed development, when combined with all other existing and anticipated development, will not increase the water surface elevation of the base flood more than one (1) foot at any point within the community.Recreational vehicles shall:Be on the site for fewer than one hundred eighty (180) consecutive days, orBe 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.When alteration or relocation of a watercourse is proposed, the State of Hawai'i Commission on Water Resource Management and the Hawai'i Department of Land and Natural Resources (Engineering) shall be notified and a copy of the notification shall be submitted to the County Engineer and the Federal Emergency Management Agency. If the State of Hawai'i Commission on Water Resource Management allows alteration and relocation of streams, the applicant shall assure the flood carrying capacity within the altered or relocated portion of any watercourse will be maintained.Development for which specific requirements are not specified in this Article shall:Be located and constructed to minimize flood damage.Be anchored to prevent flotation, collapse or lateral movement resulting from flood loads during conditions of the base flood.Be constructed of flood damage-resistant materials.Have machinery and equipment elevated to or above the base flood elevation plus one (1) foot or specifically designed to prevent water from entering or accumulating within the components during the conditions of flooding.Floodway. The floodway, identified on the FIRMs, is the watercourse reserved to discharge the base flood.Development Standard. Encroachments, including fill, new construction, repetitive loss structures, and substantial improvements of structures, are prohibited in the floodway unless certified by a registered professional civil engineer, with supporting data that the encroachment will not cause any increase in base flood elevations during the occurrence of the base flood discharge.Construction Standards. If permitted pursuant to Paragraph (1) of this Subsection, all new construction, repetitive loss structures, and substantial improvements shall comply with all applicable requirements prescribed in Subsection (a) of this Section and Section 15-1.6.Certification for Development. A registered professional civil engineer shall certify that the encroachment, including fill, new construction, repetitive loss structures, or substantial improvement will not result in any increase in base flood elevations during the occurrence of the base flood discharges.Coastal High Hazard Areas (Tsunami). Coastal high hazard areas, more commonly known as tsunami inundation areas, are identified as VE zones on the FIRMs.Anchoring and Structural Support.All new construction, repetitive loss structures, and substantial improvements shall be securely anchored on pilings or columns.Pilings or columns used as structural support shall be designed and anchored so as to prevent flotation, collapse, and lateral movement, due to the effects of wind and water loads acting simultaneously on all building components. The wind and water loading values shall each have a one percent (1%) chance of being equaled or exceeded in any given year.Fill is prohibited for structural support.Manmade alteration of sand dunes and mangrove stands is prohibited.All new construction shall be located landward of the reach of mean high tide.Construction Materials and Methods.All new construction, repetitive loss structures, and substantial improvements shall be constructed with materials resistant to flood damage.All new construction, repetitive loss structures, and substantial improvements shall be constructed using methods and practices that minimize flood damage.All electrical, heating, ventilation, plumbing, and air-conditioning equipment and other service facilities shall be elevated to or above the lowest floor.Elevation. All new construction, repetitive loss structures, and substantial improvements shall be elevated so that the bottom of the lowest horizontal structural member of the lowest floor, excluding pilings and columns, is elevated to or above the base flood elevation.Building Height. Notwithstanding the maximum building height limitations as stated in overall building and wall plate height, provided in Paragraph 8-4.5(b) for single-family detached and attached residential dwellings under the Comprehensive Zoning Ordinance and Paragraph 10-2.4(e)(l) for all structures under the North Shore Development Plan Ordinance, the maximum building height in the coastal high hazard area shall be as follows:Within the North Shore Planning Area. No structure shall be higher than twenty-five (25) feet from ground level or the base flood elevation plus fifteen (15) feet, whichever is greater at the site, unless a greater height is authorized by the Planning Commission pursuant to a use permit after review and recommendation by the North Shore Improvement Committee.Single-Family Dwellings Outside the North Shore Special Planning Area. No single-family detached and attached dwellings outside the North Shore special planning area shall be higher than thirty (30) feet from ground or the base flood elevation plus fifteen (15) feet, whichever is greater at the site unless otherwise permitted by the Planning Commission.Enclosure of Space Below Lowest Floor with Breakaway Walls. Space below the lowest floor may be enclosed solely for parking of vehicles, building access, or storage; no machinery or equipment which services a building such as furnaces, air conditioners, heat pumps, hot water heaters, washers, dryers, elevator lift equipment, electrical junction and circuit breaker boxes, and food freezers are permitted; however, enclosure must only be achieved with breakaway walls, open wood latticework, or insect screening intended to collapse under wind and water loads without causing collapse, displacement, or other structural damage to the elevated portion of the building or supporting foundation system. A breakaway wall shall have a design safe loading resistance of not less than ten (10) and no more than twenty (20) pounds per square foot. Use of breakaway walls which exceed a design safe loading resistance of twenty (20) pounds per square foot may be permitted only if a registered professional structural engineer that the design proposed meet the following conditions:Breakaway wall collapse shall result from a water load less than that which would occur during the base flood; andThe elevated portion of the building and supporting foundation system shall not be subject to collapse, displacement, or other structural damage due to the effects of wind and water loads acting simultaneously on all building components (structural and nonstructural). Maximum wind and water loading values to be used in this determination shall each have one percent (1%) chance of being equaled or exceeded in any given year (100-year mean occurrence interval).Water and Sewer.All new and replacement water supply and sanitary sewage systems shall be designed to minimize or eliminate infiltration of floodwaters into the system and discharge from systems into floodwaters.On-site waste disposal systems shall be located to avoid impairment to them or contamination from them during flooding.Certification by Engineer or Architect. Building plans for new construction, repetitive loss structures, and substantial improvements shall be certified by a registered professional structural engineer or architect that the new construction or substantial improvement is designed and methods of construction to be used are in accordance with accepted standards of practice for meeting the requirements of this Section. Prior to the issuance of the certificate of occupancy, the elevation of the bottom of the lowest structural member of the lowest floor shall be certified by a registered professional civil engineer or land surveyor.All new construction, repetitive loss structures, and substantial improvements shall be designed (or modified) and adequately anchored to prevent flotation, collapse, or lateral movement of the structure resulting from hydrodynamic and hydrostatic loads, including the effects of wind and buoyancy, be constructed with materials resistant to flood damages and be constructed by methods and practices that minimize flood damages.The placement of mobile homes or manufactured homes in the coastal high hazard flood zone is prohibited.Recreational vehicles placed on sites within Zone VE on the community's FIRM shall either:Be on the site for fewer than one hundred eighty (180) consecutive days, orBe 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.Development for which specific requirements are not specified in this Article shall:Be located and constructed to minimize flood damage.Be anchored to prevent flotation, collapse or lateral movement resulting from flood loads during conditions of the base flood.Be constructed of flood damage-resistant materials.Have machinery and equipment elevated to or above the base flood elevation plus one (1) foot.General Floodplain. The general floodplain, identified as A, X and D zones on the FIRMs, are areas of special flood hazards for which detailed engineering studies were not done by the Federal Emergency Management Agency to determine the base flood elevations and to identify the floodways.Determination of Flood Hazards. The County Engineer shall obtain, review, and reasonably utilize any base flood elevation and floodway data available from a Federal, State, or other source, including information requested of the applicant, to determine base flood elevations and the location of floodways in the general floodplain and to determine whether the proposed building sites or subdivisions (including manufactured home parks) will be reasonably safe from flooding.Determination of Applicable Construction and Development Standards. Construction and development standards provided in Subsections (a) and (b) of this Section shall apply to new construction, repetitive loss structures, and substantial improvements in general floodplains identified as A and D zones on the FIRM, and shall apply to new construction and substantial improvements in general floodplains identified as X zones on the FIRM, when determined applicable by the County Engineer. The applicable standards in Subsection (a) of this Section shall apply to development other than new construction, repetitive loss structures, and substantial improvements in general floodplain identified as A and D zones on the FIRM, when determined applicable by the County Engineer.Information to be Provided. The following information shall be provided to the County Engineer to evaluate the proposed construction on improvement site:Project location and site plan showing dimensions.Relationship to floodway and flood fringe areas as determined by flood study.Topographic data, contours, or spot elevations based on reference marks on flood maps.Existing and proposed flood-proofing and flood control measures.Elevation (in relation to mean sea level) of the lowest floor (including basement) of all new and substantially improved structures; and if the structure has been floodproofed, the elevation to which the structure was floodproofed.The State of Hawai'i Commission on Water Resource Management and the Hawai'i Department of Land and Natural Resources (Engineering) shall be notified prior to any alteration or relocation of a watercourse and a copy of the notification shall be submitted to the County Engineer and the Federal Emergency Management Agency. If the State of Hawai'i Commission on Water Resource Management allows alteration and relocation of streams, the applicant shall assure the flood carrying capacity within the altered or relocated portion of any watercourse will be maintained.A record of all of this information shall be maintained by the County Engineer.Construction of Development Adjacent to Drainage Facility Outside Identified Special Flood Hazard Areas.Subject to Review. All new construction, repetitive loss structures, and substantial improvements proposed adjacent to a drainage facility outside of the special flood hazard area identified on the FIRMs shall be subject to review and approval of the County Engineer. Upon request by the County Engineer further information concerning base flood, floodway, surface water run-off, existing and proposed drainage patterns, and other information, including flood studies, findings and opinions by a registered professional civil engineer shall be provided to evaluate potential flooding.Development and Construction Standards.The County Engineer shall determine the applicability of the various development and construction standards provided in this Article based upon best information available from a Federal, State, or other source, including information provided by the applicant.No drainage facility shall be modified, constructed, lined, or altered in any way unless approved by the County Engineer.