The Legislature of the State of Nevada has delegated the responsibility to local governmental units to adopt regulations designed to promote the public health, safety and general welfare of its citizenry. Therefore, pursuant to Nevada Revised Statutes chapters 244, 278 and 543, including the sections 244A.057, 278.020 and 543.020, together with the applicable Code of Federal Regulations, and as a participating County in the National Flood Insurance Program (NFIP), the County Commissioners of Lyon County ordain and adopt the floodplain management provisions as set forth in this chapter. (Ord. 603, 11-1-2018; amd. Ord. 607, 9-19-2019)

   A.   The flood hazard areas of Lyon County are subject to periodic inundation which results in loss of life and property, health and safety hazards, disruption of commerce and governmental services, extraordinary public expenditures for flood protection and relief and impairment of the tax base, all of which adversely affect the public health, safety and general welfare.

   B.   These flood losses are caused by uses that are inappropriately developed within the flood hazard areas or are inadequately elevated, flood-proofed, or otherwise not protected from flood damage. The cumulative effect of obstructions in areas of special flood hazards increase flood heights and velocities and, when inadequately flood proofed, elevated or otherwise protected from flood damage, contribute to the flood loss.

   C.   Protecting the natural resources and functions of floodplains, has proven to be effective in reducing flood losses. FEMA encourages and provides incentives to communities to adopt and implement programs that preserve the integrity of floodplain resources and functions. Lyon County has adopted the Carson River Watershed Floodplain Management Plan which includes strategies for floodplain management to reduce flood damage impacts including:

      1.   Protection of natural floodplain function and values;

      2.   Higher regulatory standards;

      3.   Flood data information and maintenance;

      4.   Channel migration and bank erosion monitoring;

      5.   Floodplain and flood hazard outreach and education; and

      6.   Reduction of infrastructure impacts. (Ord. 603, 11-1-2018; amd. Ord. 607, 9-19-2019)

It is the purpose of this chapter to promote the public health, safety and general welfare and to minimize public and private losses due to flood conditions in specific areas by provisions designed:

   A.   To protect human life and health;

   B.   To minimize expenditure of public money for costly flood control projects;

   C.   To minimize the need for rescue and relief efforts associated with flooding and generally undertaken at the expense of the general public;

   D.   To help maintain a stable tax base by providing for the sound use and development of areas of special flood hazard so as to minimize future flood blight areas;

   E.   To minimize damage to public facilities and utilities such as water and gas mains, electric, telephone and sewer lines, and streets and bridges located in areas of special flood hazards;

   F.   To help maintain a stable tax base by providing for the sound use and development of areas of special flood hazard and X (Shaded) flood zones to minimize property devaluation resulting from flood damage and events, and future flood blight areas;

   G.   To ensure that property owners and potential buyers are notified when a property is located in areas of special flood hazard and X (Shaded) flood zones;

   H.   To ensure that those who occupy the areas of special flood hazard and X (Shaded) flood zones assume responsibility for their actions;

   I.   Implement the Carson River Regional Floodplain Management Plan;

   J.   Minimize public and private losses due to flood conditions within the Carson River floodplain by requiring the use of the Carson River Hydraulic Model and procedures designed to provide a consistent and complete:

      1.   Tool to assess cumulative impacts of land use changes within the 1-percent chance (100-year) and 0.2-percent chance (500-year) floodplains;

      2.   Tool to assess project specific impacts of land use changes within the 1-percent chance (100-year) and 0.2-percent chance (500-year) floodplains;

      3.   Tool for mitigating flood hazards to downstream communities, loss of riparian habitat and floodplain function, and degradation of water quality due to impacts of land use changes within the 1-percent chance (100-year) and 0.2-percent chance (500-year) floodplains;

      4.   Set of protocols, procedures and guidance necessary to use the Carson River Hydraulic Model to evaluate impacts to floodplain extents, peak flow, peak flow timing, and flood volumes.

   K.   To maintain eligibility for State and Federal disaster relief;

   L.   Maintain qualifying standards for participation in the National Flood Insurance Program (NFIP); and

   M.   Comply with applicable Code of Federal Regulations provisions. (Ord. 603, 11-1-2018; amd. Ord. 607, 9-19-2019)

In order to accomplish its purposes, this chapter includes methods and provisions for:

   A.   Restricting or prohibiting uses which are dangerous to health, safety and property due to water or erosion hazards or which result in damaging increases in erosion or in flood heights or velocities;

   B.   Requiring that uses vulnerable to floods, including facilities which serve such uses, be protected against flood damage at the time of initial construction;

   C.   Controlling the alteration of natural floodplains, stream channels, alluvial fans, and natural protective barriers which help accommodate or channel floodwaters;

   D.   Controlling filling, grading, dredging and other development which may increase flood damage; and

   E.   Preventing or regulating the construction of flood barriers which will unnaturally divert floodwaters or may increase flood hazards in other areas. (Ord. 603, 11-1-2018; amd. Ord. 607, 9-19-2019)

Definitions of many of the words used in this chapter are contained in chapter 1200 of this title, appendix A. Unless specifically defined in chapter 1200 of this title, appendix A or in this chapter, or as used throughout this title, the words and phrases used in this chapter should be interpreted to give them the meaning they have in common usage and to give this chapter its most reasonable application. The Director or their designee is the Floodplain Administrator for the County. (Ord. 603, 11-1-2018; amd. Ord. 607, 9-19-2019)

   A.   This chapter shall apply to all areas of special flood hazards within the jurisdiction of the County.

   B.   In the interpretation and application of this chapter, all provisions shall be:

      1.   Considered as minimum requirements;

      2.   Construed in favor of the board to promote public health, safety and welfare; and

      3.   Deemed neither to limit nor repeal any other powers granted under State Statutes or local ordinance.

   C.   This chapter is not intended to repeal, abrogate or impair any existing easements, covenants or deed restrictions. However, where this chapter and another ordinance, easement, covenant or deed restriction conflict or overlap, whichever imposes the more stringent restrictions shall prevail.

   D.   No structure or land shall hereafter be constructed, located, extended, converted or altered without full compliance with the terms of this chapter and other applicable regulations. Violations of this requirement (including violations of conditions and safeguards established in connection with conditions) shall constitute a misdemeanor. Any person who violates this chapter or fails to comply with any of its requirements shall upon conviction be guilty of a misdemeanor of each violation, and in addition shall pay all costs and expenses involved in the case. Nothing in this chapter shall prevent Lyon County or its board from taking such lawful action as is necessary to prevent or remedy any violation.

   E.   After discovery of a violation or alleged violation of this chapter, the Floodplain Administrator shall take action to verify the existence of a violation(s) and remedy the violation(s) through administrative means including stop work orders or other provisions of this title or applicable laws. If a property owner fails to remedy any violation of this chapter, the Administrator may submit a report to the board which shall include all information available to the Floodplain Administrator which is pertinent to said violation, and request that the board:

      1.   Take any necessary action to effect the abatement of such violation; or

      2.   Issue a variance to this chapter in accordance with the provisions of section 15.800.14 of this chapter; or

      3.   Submit to the Administrator of Federal Insurance Administration a declaration for denial of insurance, stating that the property is in violation of a cited statute or local law, regulation or ordinance, pursuant to section 1316 of the National Flood Insurance Act of 1968, as amended.

   F.   It is unlawful for any person to divert, retard or obstruct the flow of waters in any watercourse whenever it creates a hazard to life or property without securing the appropriate local, state and/or Federal permit(s). Any person violating the provisions of this section shall be guilty of a misdemeanor. (Ord. 603, 11-1-2018; amd. Ord. 607, 9-19-2019)

   A.   Flood Insurance Study And Maps: The areas of special flood hazard and X (Shaded) flood zones identified by the Federal Insurance Administration in a scientific and engineering report entitled "the Flood Insurance Study for Lyon County" (FIS), dated January 19, 1982, with accompanying flood insurance rate maps (FIRMS), and all subsequent revisions and amendments, are hereby adopted by reference and declared to be a part of this chapter. The FIS and supplemental mappings, as amended and revised, is the minimum area of applicability of this chapter and may be supplemented by studies for other areas that allow implementation of this chapter and that are recommended to the board by the Floodplain Administrator. The flood insurance study and flood insurance rate maps (FIRMS) are is on file at the department for public reference and review.

   B.   Interpretations: Interpretations, where needed, as to location of the boundaries of the areas of special flood hazards (for example, where there appears to be a conflict between a mapped boundary and actual field conditions) shall be made by the Floodplain Administrator. The Floodplain Administrator may determine the best information available in making the map determinations. When requested by the Floodplain Administrator, the applicants shall provide documentation to assist the Floodplain Administrator in making the determination. The person contesting the location of the boundary shall be given a reasonable opportunity to appeal the interpretation as provided in section 15.800.14 of this chapter.

   C.   Use Of Other Base Flood Data: When base flood elevations are not available, the Floodplain Administrator may obtain, review, and use the best available flood data and information from any other authoritative source, such as state, federal, or other such as historical data, high water marks, floods of record, or private engineering reports, to establish base flood elevations within the special flood hazard areas (SFHAs). Multiple parcels (five (5) or more) will be required to have all proposals establish the one hundred-year base flood elevation before consideration of the tentative plan for development. The Floodplain Administrator may, at their discretion, require standards exceeding those identified in this chapter. Any higher standards above those in this chapter This information shall be submitted to the Board for adoption. When base flood elevations are not available from any other source, base flood elevations shall be obtained using one of two (2) methods from the FEMA publication, FEMA 265, "Managing Floodplain Development in Approximate Zone A Areas - A Guide for Obtaining and Developing Base (100-Year) Flood Elevations", dated July 1995.

   D.   Information Obtained And Maintained:

      1.   Where base flood elevation data is provided through the flood insurance study or acquired as in subsections B and C of this section, the actual elevation (in relation to mean sea level) of the lowest floor (including basement) of all new or substantially improved structures and whether or not the structure contains a basement shall be obtained and recorded.

      2.   For all new or substantially improved flood proofed structures:

         a.   The actual elevation (in relation to mean sea level) shall be verified and recorded; and

         b.   The flood proofing certifications required in subsection 15.800.08B of this chapter shall be maintained.

      3.   All records pertaining to the provisions of this chapter shall be maintained for public inspection.

   E.   Hydrology And Hydraulic Study Requirements: Detailed Base Flood Elevations (BFEs) are determined by an engineering study consisting of hydrology and hydraulics. All hydrology and hydraulic studies (also known as Flood Impact Analysis) referenced in the chapter must be prepared by a professional engineer licensed in the State of Nevada and meet FEMA standards for hydrology and hydraulic studies submitted for the approval of CLOMRs and LOMRs. Except for areas were FEMA allows the use of the approximate method, the preferred modeling tool to determine changes on the base flood elevations and the floodplain boundary shall be the current acceptable version of HEC-RAS.

   F.   Carson River Floodplain Hydraulic Modeling:

      1.   The Carson River Floodplain Hydraulic Model (Model) is hereby adopted as the hydraulic modeling/mapping tool to assess impacts of land use changes, development, construction, and man-made alterations within the Carson River floodplain.

      2.   The Carson River Hydraulic Model - Model Management, Distribution, And Update Guide (Guide), including revisions, amendments and updates, is hereby adopted as the required procedures and guidance for the use of the model, including management, distribution, modification, submission and review.

      3.   Lands to which the Carson River Floodplain Hydraulic Modeling Applies. The Carson River Floodplain Hydraulic Modeling shall apply to all areas of special flood hazards within the 1-percent chance (100-year) and 0.2-percent chance (500-year) floodplains of the Carson River within the jurisdiction of Lyon County.

      4.   The most current version of the model shall be used for the following:

         a.   Interpretations as set forth in subsection 15.800.07 B.

         b.   Use of other base data as set forth in subsection 15.800.07 C.

         c.   For information for the application of a development permit as required in subsections 15.800.08 B6, B7 and B8.

         d.   For the issuing of a permit for any alteration of watercourse as set forth in subsection 15.800.09.

         e.   For compliance with the provisions of subsection 15.800.12 A.

         f.   For compliance with the provisions of subsection 15.800.13 D 1, "Specific Standards for Flood Hazard Reduction."

         g.   For compliance with the provisions of and providing information for subsection 15.800.14 C, "Variances and Appeals."

         h.   For compliance with the provisions of and providing information for subsection 15.800.15, "Letters of Map Revision/Amendment."

      5.   Use of the model shall be performed by the Carson Water Subconservancy District contractor/consultant employed to maintain and operate the model in conformance with the procedures and guidelines set forth in the most current version of the Guide.

      6.   Applications for model use shall be made on forms furnished by the department, contain the information stipulated in the forms, and be accompanied by any applicable fees. The applicant is responsible for the cost of the Carson Water Subconservancy District contractor/consultant to operate the model, analyze the data and provide a report. (Ord. 603, 11-1-2018; amd. Ord. 607, 9-19-2019)

   A.   Permit Required: A floodplain development permit shall be obtained before construction or development begins within any area of special flood hazard established in subsection 15.800.07A of this chapter. The permit shall be for all structures, including manufactured homes, accessory dwelling units and accessory structures whether a building permit is required or not required as defined herein or in chapter 1200 of this title, appendix A, and for all development, including fill and other activities, including river bank and stream bank erosion repair activities, as defined in chapter 1200 of this title, appendix A.

   B.   Application For Permit: Applications for a permit shall be made on forms furnished by the department, contain the information stipulated in the forms, and be accompanied by any applicable fees. The applicant shall provide at least the following information, where applicable. Additional information may be required as determined by the Floodplain Administrator.

      1.   The proposed elevation in relation to mean sea level, of the lowest floor (including basement) of all residential and nonresidential structures whether new or substantially improved to be located in Zones A, A1-A30, AE, AH and X (Shaded), if base flood elevations data are available.

      2.   In Zone AO the proposed elevation in relation to the elevation of the highest adjacent grade of all residential and nonresidential structures whether new or substantially improved.

      3.   The proposed elevation in relation to mean sea level, to which any new or substantially improved nonresidential structure will be flood proofed.

      4.   A certificate from a licensed professional engineer or architect in the State of Nevada that any utility flood proofing meets the criteria in subsection 15.800.12D, "Utilities", of this chapter.

      5.   A certificate from a licensed professional engineer or architect in the State of Nevada that any nonresidential flood proofed structures meet the criteria in sections 15.800.12 and 15.800.13 of this chapter.

      6.   When a watercourse will be altered or relocated as a result of the proposed development, the applicant must submit a ‘No-Rise’ certificate and the maps, computations, and other materials required by the Federal Emergency Management Agency (FEMA) to process a conditional letter of map revision (CLOMR) or a letter of map revision (LOMR) and pay any fees or other costs assessed by FEMA for processing the revision.

      7.   A technical analysis, by a professional engineer licensed in the State of Nevada, showing the proposed development located in the special flood hazard area will not cause physical damage to any other property.

      8.   When there is no base flood elevation data available for Zone A from any source, the base flood elevation data will be provided by the permit applicant for all proposed development of subdivisions, manufactured home and recreational vehicle parks in the special flood hazard areas, for all developments of fifty (50) lots or five (5) acres, whichever is less.

   C.   Permit Review And Approval: The Director or their designee is appointed Floodplain Administrator to administer and implement this chapter by granting or denying floodplain development permit applications in accordance with its provisions.

      Duties and responsibilities of the Floodplain Administrator shall include, but not be limited to:

      1.   Review all floodplain development permit applications to determine that the permit requirements of this chapter have been satisfied.

      2.   Review all floodplain development permits to determine that all necessary permits have been obtained from those Federal, State or local governmental agencies from which prior approval is required prior to issuing the floodplain development permit.

      3.   Review all floodplain development permits to determine that the site and structure(s) is/are reasonably safe from flooding.

      4.   Review of all floodplain development permit applications to determine if the proposed development in the Special Flood Hazard Area (SFHA) may result in physical damage to any other property, to include river and stream bank erosion and any increase in velocities or that it does not adversely affect the flood-carrying capacity of the area where base flood elevations have been determined, but a floodway has not been designated. For purposes of this chapter, "adversely affected" means 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 0.5 foot at any point. To assist the local floodplain administrator in making this determination, the applicant requesting the floodplain development permit, may be required to submit additional technical analyses.

      5.   Review of all proposals for the development of five (5) parcels or more to assure that the flood discharge exiting the development after construction is equal to or less than the flood discharge at the location prior to development.

      6.   Review all development applications to determine that all necessary permits have been obtained from those federal, state, or local governmental agencies from which prior approval is required.

      7.   May make map interpretations where needed, as to the location of the boundaries of special flood hazard areas and where there appears to be a conflict between a mapped boundary and actual field conditions. The Floodplain Administrator may determine the best information available in making the map determinations. Floodplain development permit applicants must provide documentation to assist the Floodplain Administrator or designee in making the determination when requested by the Floodplain Administrator.

      8.   Submit new technical data to FEMA when the Floodplain Administrator has received technical or scientific data that the base flood elevation has either increased or decreased resulting from physical changes affecting flooding conditions. The Floodplain Administrator will submit the technical or scientific data to FEMA, as soon as practical, after the date of technical information confirming the physical changes becomes available. The technical or scientific data provided to the Floodplain Administrator shall meet the FEMA notebook-style format as preferred.

      9.   The Planning Commission and board shall be responsible for reviewing all proposals for new development and shall weigh all requests for future floodplain development against the county's master plan and multi-jurisdictional hazard mitigation plan. Consideration of the following elements is required before approval:

         a.   Determination of whether a proposed development is in or affects a known floodplain.

         b.   Inform the public of the proposed activity.

         c.   Determine if there is a practicable alternative or site for the proposed activity.

         d.   Identify impact of the activity on the floodplain.

         e.   Provide a plan to mitigate the impact of the activity. (Ord. 603, 11-1-2018; amd. Ord. 607, 9-19-2019)

Prior to issuing a floodplain development permit for any alteration or relocation of watercourse the Floodplain Administrator must:

   A.   Have processed and received a conditional letter of map revision (CLOMR) and processed and received a letter of map revision (LOMR) through FEMA.

   B.   Notify all adjacent communities, Nevada's National Flood Insurance Program Coordinator, and submittal of evidence of such notification to the Federal Insurance Administration, and the Federal Emergency Management Agency.

   C.   Determine that the potential permit recipient has provided:

      1.   A description of the extent to which the watercourse will be altered or relocated as a result of the proposed development;

      2.   Computations by a professional engineer licensed in the State of Nevada that demonstrate that the altered or relocated segment will provide equal or more capacity than the original watercourse;

      3.   A legally enforceable assurance instrument for maintenance within the altered or relocated portion of said watercourse so that the flood carrying capacity is not diminished;

      4.   Have received a Conditional Letter of Map Revision (CLOMR) determination from FEMA; and

      5.   Provided funds from the Developer to the County for processing the Letter of Map Revision (LOMR).

   D.   Development Of Substantial Improvement And Substantial Damage Procedures:

      1.   Using the most recent version of FEMA publication FEMA 213, "Answers to Questions About Substantially Damaged Buildings," develop detailed procedures for identifying and administering requirements for substantial improvement and substantial damage, to include defining "Market Value." (Ord. 603, 11-1-2018; amd. Ord. 607, 9-19-2019)

The Floodplain Administrator shall obtain and retain for public inspection and have available for the National Flood Insurance Program Coordinator or the Federal Emergency Management Agency representative conducting a community assistance visit, the following:

   A.   Floodplain development permits and certificates of compliance.

   B.   Elevation required by section 15.800.13 of this chapter (lowest floor elevation).

   C.   Certification required by section 15.800.13 of this chapter (flood proofing nonresidential structures).

   D.   Elevation certificates with records of certification required for areas below the lowest floor.

   E.   Elevation certificates and all certifications of elevation required by section 15.800.12 of this chapter (subdivision standards).

   F.   Certification required by section 15.800.13 of this chapter (floodway encroachments - also referred to as a "no-rise certification" by the National Flood Insurance Program (NFIP)):

      1.   The no-rise certification shall be supported by technical data and signed by a professional engineer licensed in the State of Nevada.

      2.   The supporting technical data shall be based on a FEMA approved model used to develop the 100-year floodway shown on the FIRM and the results tabulated in the Flood Insurance Study.

      3.   In a special flood hazard area, a no-rise certification must be submitted for any construction or other development that is permitted to proceed with a CLOMR on a form approved by the administrator and prepared by a professional engineer licensed in the State of Nevada.

   G.   Variances issued pursuant to section 15.800.14, "Variances And Appeals", of this chapter.

   H.   Notices required under section 15.800.09, "Alteration Of Watercourses", of this chapter and any notices required for the addition of fill material.

   I.   Copies of approved elevations, footing details, and site plans.

   J.   Copies of approved CLOMRs, LOMRs, LOMR-Fs, and LOMAs. (Ord. 603, 11-1-2018; amd. Ord. 607, 9-19-2019)

The maintenance of any and all flood protection measures (levees, dikes, dams or reservoirs) and alterations or relocations of watercourses will be required of the jurisdiction where such measures provide protection. If these measures are privately owned, an operation or maintenance plan and an operations or maintenance agreement document, including enforcement provisions as recorded with Lyon County will be required of the owner to be on file with the department. (Ord. 603, 11-1-2018; amd. Ord. 607, 9-19-2019)

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

   A.   Development Requirements:

      1.   All preliminary subdivision proposals shall identify the special flood hazard area and X (Shaded) flood zone and the elevation of the base flood;

      2.   All final subdivision plans will provide the elevation of proposed structure(s), pads, and adjacent grade. 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 as set forth in this chapter;

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

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

      5.   All subdivision proposals shall have adequate drainage provided to reduce exposure to flood damage; certification of compliance shall be required of the developer; and

      6.   Where base flood elevation data has not been provided or is not available from another authoritative source, it shall be generated for subdivisions and other proposed developments which contain at least fifty (50) lots or five (5) acres (whichever is less).

      7.   All subdivision proposals and other proposed developments shall assess the cumulative and project specific impacts of land use changes and development through a detailed hydrologic and hydraulic analyses and/or demonstration of the cumulative effect of the proposed land use changes or development. All subdivision proposals must demonstrate that 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-half (0.5) foot at any point within the special flood hazard area;

      8.   Whenever any portion of a floodplain is authorized for use, the space occupied by the authorized fill or structure below the base flood elevation shall be compensated for and balanced by a hydraulically specified volume of excavation taken from below the base flood elevation. All such excavations shall be constructed to drain freely to the watercourse. All new development placing fill and structures within special flood hazard areas must provide compensatory storage at hydraulically equivalent sites at a minimum ratio of 1.25:1 (i.e., where 1.25 cubic feet of material must be removed from a hydraulically equivalent location for each 1 cubic foot of fill placed in the special flood hazard zone); and

      9.   Land may not be divided for residential purposes that requires fill to raise the elevation of the property to remove the property out of a special flood hazard area and enable subsequent development.

      10.   Land may not be divided for residential purposes that will result in the creation of a parcel that is less than twenty (20) net acres, unless the applicant shows that:

         a.   The portion of the land in the special flood hazard area will be contained on a single parcel; and

         b.   The land within the special flood hazard areas is retained in a natural state including, without limitation, no solid fencing that impedes the flow of floodwaters or other improvements; and

         c.   The land within the special flood hazard area is held in common or single ownership with any overlying drainage easement; and

         d.   A property owner's association or similar entity is legally responsible for maintenance of the land in the special flood hazard area in its natural state.

   B.   Anchoring:

      1.   All new construction and substantial improvements 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 must likewise be anchored to prevent flotation, collapse or lateral movement and shall be installed using methods and practices that minimize flood damage. Anchoring methods may include, but are not limited to, use of over the top or frame ties to ground anchors (see FEMA's "Manufactured Home Installation in Flood Hazard Areas" guidebook for additional techniques).

      3.   Propane and other liquid or gaseous fuel storage tanks shall be anchored to prevent flotation or lateral movement.

   C.   Construction Materials And Methods:

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

      2.   Design And Construction Methods And Practices: All new construction and substantial improvements shall be designed and constructed using methods and practices that minimize flood damage and comply with FEMA requirements.

      3.   Location Of Service Facilities: Electrical, heating, ventilation, plumbing and air conditioning equipment and other service facilities shall be designed and/or otherwise elevated or located so as to prevent water from entering or accumulating within the components during conditions of flooding.

      4.   Drainage Paths: Within Zones AH or AO, all new construction and substantial improvements shall be constructed so that there are adequate drainage paths around structures on slopes to guide floodwaters around and away from proposed structures.

      5.   Elevation And Flood Proofing:

         a.   New construction and substantial improvement of any structure shall have the lowest floor, including basement, elevated to create freeboard above the base flood elevation or constructed with the freeboard requirement or depth number as follows:

            (1)   In Zone AO: The lowest floor elevated above the highest adjacent grade to a height equal to or exceeding the depth number specified in feet on the FIRM by at least one and one half feet (1.5’), or elevated at least three and one-half feet (3.5’) above the highest adjacent grade if no depth number is specified. A professional surveyor or engineer licensed in the State of Nevada must complete the elevation certificate.

            (2)   In Zone A: The lowest floor elevated to at least one and one half feet (1.5’) or above the base flood elevation, as determined by a professional engineer or surveyor licensed in the State of Nevada and approved by the Floodplain Administrator.

            (3)   In all other special flood hazard areas where the base flood elevation has been determined: The lowest floor elevated at least one and one half feet (1.5’) above the base flood elevation.

            (4)   In all the X-shaded flood zone, one of the following minimum criteria must be met:

               (A)   The lowest floor must be elevated at least one and one-half feet (1.5’) above the pre-developed highest adjacent grade; or

               (B)   The applicant must provide a drainage plan designed by a professional engineer licensed in the State of Nevada for diverting water around the proposed structure using berms, swales, or other drainage features.

            (5)   In alluvial fan floodplain areas as designated within the Area Drainage Master Plans, the lowest floor must be a minimum of two feet (2') above the Base Flood Elevation to account for sedimentation.

         b.   Manufactured homes that are placed or substantially improved within a SFHA:

            (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,

      On 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 elevated at least one and one-half feet (1.5’) above the base flood elevation and be securely anchored to an adequately anchored foundation system to resist flotation collapse and lateral movement in addition to meeting the above standards.

      Nonresidential structures may meet the standards in subsection C5c of this section. Upon completion of the structure, the elevation of the lowest floor, including basement, shall be certified by a registered professional engineer or surveyor to verify to the Floodplain Administrator that elevation requirements have been met. Notification of compliance shall be recorded as set forth in subsection C5a of this chapter.

         c.   Nonresidential construction shall either be elevated to conformance with subsection C5a of this section or, together with attendant utility and sanitary facilities:

            (1)   Be flood proofed so that below the base flood level the structure is watertight with walls substantially impermeable to the passage of water;

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

            (3)   Be certified by a professional engineer or architect licensed in the State of Nevada that the standards of this subsection are satisfied. Such certifications shall be provided to the Floodplain Administrator.

         d.   All new construction and substantial improvements to existing structures within a special flood hazard area 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, must be designed to automatically equalize hydrostatic and hydrodynamic flood forces on exterior walls by allowing for the entry and exit of flood waters. Designs for meeting this requirement shall follow the guidelines in FEMA Technical Bulletins TB-1 (Openings in Foundation Walls and Walls of Enclosures, 2008) and TB-7 (Wet Floodproofing Requirements, 1993) and must either be certified by a professional engineer or architect licensed in the State of Nevada or meet or exceed the following minimum criteria:

            (1)   Have a minimum of two openings on different sides having a total net area of not less than one square inch for every square foot of enclosed area subject to flooding. Net area may be reduced by manufacturer or engineer certification if engineered flood openings are used. If a structure has more than one enclosed area, each area must have openings on different sides to allow floodwaters to directly enter and exit. Openings must be equipped with FEMA approved louvers and other designated openings that permit the automatic entry and exit of flood waters.

            (2)   The bottom of all such openings must be no higher than one foot above the exterior lowest adjacent finished grade and be installed below the base flood elevation.

            (3)   Have an adequate drainage system that removes floodwaters from the interior.

            (4)   Areas below the BFE must be constructed with flood resistant materials.

         e.   Upon the completion of the structure, the elevation of the lowest floor including basement shall be certified by a professional engineer or land surveyor licensed in the State of Nevada and verified by the county building inspector to be properly elevated. Such certification or verification shall be provided to the floodplain administrator using the current FEMA Elevation Certificate.

      6.   Requirements For All Crawl Space Construction:

         a.   The building must be designed and adequately anchored to resist flotation, collapse, and lateral movement of the structure resulting from hydrodynamic and hydrostatic loads, including the effects of buoyancy. Hydrostatic loads and the effects of buoyancy can usually be addressed through the required openings discussed in the next subsection. Because of hydrodynamic loads, crawl space construction is not recommended in areas with flood velocities greater than five feet (5') per second unless the design is reviewed by a qualified design professional, such as an architect or professional engineer licensed in the State of Nevada.

         b.   The crawl space is an enclosed area below the BFE or depth number and, as such, must have openings that equalize hydrostatic pressures by allowing for the automatic entry and exit of floodwaters. The bottom of each flood vent opening can be no more than one foot (1') above the highest of inside or outside adjacent grade.

         c.   Portions of the building below the BFE or depth number must be constructed with materials resistant to flood damage. This includes not only the foundation walls of the crawl space used to elevate the building, but also any joists, insulation, or other materials that extend below the BFE or depth number. The required construction practice is to elevate the bottom of joists and all insulation two feet (2') above BFE or depth number. Insulation is not a flood resistant material. When insulation becomes saturated with floodwater, the additional weight often pulls it away from the joists and flooring. Ductwork or other utility systems located below the insulation may also pull away from their supports.

         d.   Any building utility systems within the crawl space must be elevated above BFE or depth number, or designed so that floodwaters cannot enter or accumulate within the system components during flood conditions. Ductwork, in particular, must either be placed above the BFE or depth number, or sealed from floodwaters.

         e.   Additional requirements for below grade crawl spaces:

            (1)   The interior grade of a crawl space below the BFE or depth number must not be more than two feet (2') below the highest adjacent exterior grade (HAG), shown as "D" in figure 3 of this section.

            (2)   The height of the below grade crawl space, measured from the interior grade of the crawl space to the top of the crawl space foundation wall must not exceed four feet (4') (shown as "L" in figure 3 of this section) at any point. The height limitation is the maximum allowable unsupported wall height according to the engineering analyses and Building Code requirements for flood hazard areas. This limitation will also prevent these crawl spaces from being converted into habitable spaces, in conjunction with the requirement of a "non-convert to living space" agreement recorded with the County prior to the final inspection.

            (3)   There must be an adequate drainage system that removes floodwaters from the interior area of the crawl space. The enclosed area should be drained within a reasonable time after a flood event. The type of drainage system will vary because of the site gradient and other drainage characteristics, such as soil types. Possible options include natural drainage through porous, well drained soils and drainage systems such as perforated pipes, drainage tiles, or gravel or crushed stone drainage by gravity or mechanical means.

            (4)   The velocity of floodwaters at the site should not exceed five feet (5') per second for any crawl space. For velocities in excess of five feet (5') per second, other foundation types should be used.

   D.   Utilities:

      1.   All public utilities and facilities must be located and constructed to minimize flood damage.

      2.   All new and replacement water supply systems must be designed to prevent infiltration and intermingling of flood waters.

      3.   All new and replacement sanitary sewage systems shall be designed to minimize or eliminate infiltration and intermingling of floodwaters or discharge from the systems into floodwaters. Sanitary sewer and storm drainage systems for buildings that have openings below the base flood elevation shall be provided with automatic backflow valves or other automatic backflow devices that are installed in each discharge line passing through a building's exterior wall.

      4.   New and replacement sanitary sewage systems shall be designed to minimize or eliminate infiltration of floodwaters into the systems and discharge from the systems into floodwaters; and

      5.   On site waste disposal systems shall be located to avoid impairment to them or contamination from them during flooding.

      6.   All electrical, heating, ventilation, plumbing, and air conditioning (HVAC) systems and other service facilities and mechanical equipment (including ductwork) must be elevated, made of flood-resistant materials, or floodproofed above the base flood elevation to the elevation (freeboard) required in the applicable special flood hazard zone and X-shaded flood zone; and be located and constructed to prevent water from entering or accumulating within the components during conditions of flooding.

   E.   Standards For Critical Facilities: Critical facilities, as defined in Appendix A of this title, are not permitted to be constructed within a special flood hazard area, unless:

      1.   All alternative locations in the X-unshaded flood zone have been considered and rejected; and

      2.   All alternative locations in X-shaded flood zone have been considered and rejected.

      If the Floodplain Administrator determines the only practical alternative location for the development of a new or substantially improved critical facility is in a special flood hazard area, the Floodplain Administrator must give public notice of the decision and reasons for the elimination of all alternative locations. Additionally, a critical facility must be designed to higher protection standards and have flood evacuation plans if the critical facility must be located in a floodplain. The more common standards such as freeboard, elevation above the 500-year floodplain, and elevated ramps will be required. (NFIP).

   F.   Standards For Alluvial Fans: Areas subject to alluvial-fan flooding have irregular flow paths that result in erosion of existing channels and the undermining of fill material. Those areas are identified on the Flood Insurance Rate Map (FIRM) as AO Zones with velocities.

      1.   All structures must be securely anchored to minimize the impact of the flood and sediment damage.

      2.   All new construction and substantial improvements must be elevated on pilings, columns, or armored fill so that the lowest floor is elevated two feet (2’) above the depth number.

      3.   Use of all fill materials must be armored to protect the material from the velocity of the flood flow.

      4.   All proposals for subdivision development must provide a mitigation plan that identifies the engineering methods used to:

         a.   Protect structures from erosion and scour caused by the velocity of the flood flow;

         b.   Capture or transport flood and sediment flow through the subdivision to a safe point of disposition.

      5.   All manufactured homes shall be prohibited within the identified hazard area except within existing manufactured home parks or subdivisions.

      6.   Approval by the Floodplain Administrator and County Engineer is required.

   G.   Review Of Building Permits: Applications for building permits shall be reviewed to assure that proposed construction will be reasonably safe from flooding. The test of reasonableness is a local judgment and includes use of historical data, high water marks, photographs of past flooding, etc., where available. (Ord. 603, 11-1-2018; amd. Ord. 607, 9-19-2019; Ord. 613, 12-3-2020)

In all areas of special flood hazards where base flood elevation data has been provided as set forth in subsection 15.800.07A or C of this chapter, the following provisions are required:

   A.   Residential Construction:

      1.   New construction and substantial improvement of any residential structure shall have the lowest floor, including basement, elevated one and one half feet (1.5’) above base flood elevation.

      2.   Fully enclosed areas below the lowest floor other than a crawl space constructed in conformance with subsection 15.800.12C6 of this chapter subject to flooding are prohibited or 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 must meet or exceed the following minimum criteria:

         a.   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 shall be provided on opposite walls.

         b.   The bottom of all openings shall be no higher than one foot (1') above the highest inside or outside adjacent grade.

         c.   Openings may be equipped with screens, louvers or other coverings or devices; provided, that they may permit the automatic entry and exit of floodwaters.

   B.   Manufactured Homes:

      1.   All manufactured homes to be placed or substantially improved within Zones A, AH and AE shall be elevated on a permanent foundation such that the bottom of the structural frame or the lowest point of any attached appliances, whichever is lowest, of the manufactured home is at least one and one half feet (1.5’) above the base flood elevation or at least three and one half feet (3.5’) above the highest adjacent grade when no base flood elevation data is available and shall be securely anchored to an adequately anchored foundation system to resist floatation, collapse, and lateral movement in accordance with the provisions of subsection 15.800.12B2 of this chapter. This requirement is in addition to the applicable state and local anchoring requirements for resisting wind forces.

      2.   All manufactured homes to be placed or substantially improved on sites in an existing manufactured home park or subdivision within zones A, AH, and AE as shown on the community's FIRM are subject to the provisions of subparagraph 1, above.

   C.   Nonresidential Construction: New construction and substantial improvement of any commercial, industrial or other nonresidential structure shall either have the lowest floor, including basement, elevated to one and one half feet (1.5’) above the base flood elevation or, together with attendant utility and sanitary facilities, shall:

      1.   Be flood proofed so that below the base flood elevation the structure is watertight with walls substantially impermeable to the passage of water;

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

      3.   Be certified by a Nevada licensed professional engineer or architect that the design and methods of construction are in accordance with accepted standards of practice for meeting provisions of this subsection based on their development and/or review of the structural design, specifications and plans. Such certifications shall be provided to the official as set forth in subsection 15.800.08B5 of this chapter.

      4.   Nonresidential structures that are elevated, not flood proofed, must meet the same standards for space below the lowest floor as described in subsection A2 of this section.

      5.   Applicants flood proofing nonresidential buildings shall be notified that flood insurance premiums will be based on rates that are one foot (1') below the flood proofed level (e.g., a building constructed to the base flood level will be rated as 1 foot below that level).

   D.   Floodways: Located within areas of special flood hazard established in subsection 15.800.07A of this chapter or based on the best information available, 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:

      1.   Encroachments, including fill, new construction, substantial improvements and other development are prohibited unless it has been demonstrated through hydrologic and hydraulic analyses, performed in accordance with standard engineering practice, supported by technical data and signed by a professional engineer licensed in the State of Nevada, that the proposed encroachment would not result in any increase in flood levels within the community during the occurrence of the base flood discharge, and the Federal Emergency Management Agency has issued a conditional letter of map revision (CLOMR).

      2.   If a floodway has not been designated within the special flood hazard areas established in Basis for Establishing Areas of Special Flood Hazard, no new construction, substantial improvement, or other development (including fill) shall be permitted within Zones A1-30 and AE, unless it has been 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 half foot (0.5’) at any point within the county.

      3.   If subsection D1 of this section is satisfied, all new construction and substantial improvements shall comply with all applicable flood hazard reduction provisions of this section and section 15.800.12 of this chapter.

      4.   A No-Rise Certificate prepared by a professional engineer licensed in the State of Nevada must be submitted with the floodplain development application to the County.

      5.   No manufactured homes shall be placed in a floodway except in existing manufactured home parks or existing manufactured home subdivisions in compliance with the provisions of this chapter.

      6.   The above exceptions in paragraphs D(1) and (2) do not apply, and the Administrator may not issue a floodplain development review/permit for any encroachment in the adopted regulatory floodway, including without limitation, fill, new construction, substantial improvements, storage of equipment or supplies, and any other development where the encroachment involves the division of land or increases in the permitted density.

   E.   Recreational Vehicles: All recreational vehicles placed on sites within the floodplain on the FIRM will 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 a site only by quick disconnect type utilities and security devices, and has no permanently attached additions).

   F.   Breakaway Walls: A breakaway wall must have a safe design loading resistance of not less than ten (10) and no more than twenty (20) pounds per square foot. Use of breakaway wall must be certified by a professional engineer or architect licensed in the State of Nevada and must meet the following conditions:

      1.   Breakaway wall collapse must result from a water load less than that which would occur during the base flood; and

      2.   The elevated portion of the building must not incur any structural damage due to the effects of wind and water loads acting simultaneously in the event of the base flood.

   G.   All new buildings constructed on fill in the regulatory floodplain:

      1.   Must be constructed on properly designed and compacted fill (e.g., fill that meets the criteria of (1) Section 1803.5.8, Section 1804.4 and Section 1804.5.1 of the International Building Code, (2) Section 2.4 of ASCE 24, or (3) their equivalent);

      2.   Must be on fill that has appropriate protection from erosion and scour; and

      3.   Must meet a compensatory storage requirement (for the building and fill) that meets the criteria of 15.800.12A6.

   H.   Prohibition Of Outdoor Storage Of Materials:

      1.   Hazardous materials are prohibited from being stored indoors or outdoors within an area designated as special flood hazard area except as follows:

         a.   Hazardous materials for agricultural use stored indoors or outdoors within an area designated as agricultural in a special flood hazard area.

         b.   Hazardous materials may be stored indoors within structures legally existing and conforming to all building and zoning requirements as of the effective date of ________ within an area designated as a special flood hazard area if the hazardous materials are stored elevated above the base flood elevation in accordance with the lowest floor elevation requirements.

   I.   Landscaping And Landscaping Berms: The planting of landscaping in special flood hazard areas shall consider the least resistance to stormwater flow. The construction of landscaping berms within the special flood hazard area shall be designed in consideration of the direction of stormwater flow and will not be allowed to divert the direction of flow. Grading plans for any new construction where landscaping or landscape berms are proposed must show no adverse impact to the floodplain and must be included in the building permit submittal.

   J.   Multiple Flood Zones: Proposed construction, including without limitation, substantial improvement, and other development, of a parcel within multiple flood zones must be constructed to the standards of the most restrictive flood zone.

   K.   Maintenance Of Flood Protection Measures: The maintenance of any and all flood protection measures (levees, dikes, dams, or reservoirs) and alterations or relocations of watercourses will be required of the jurisdiction where such measures provide protection. If these measures are privately owned, an operation or maintenance plan and a recorded operation or maintenance agreement with the county, including enforcement provisions, will be required of the owner. The operation or maintenance plan and recorded operation or maintenance agreement must be on file with the community development department.

   L.   Disclosure Requirements: Before the purchaser of a property which is located partially or completely within a special flood hazard area, X (shaded) flood zone, or dam inundation area signs a sales agreement, opens escrow or at least ten (10) days prior to any conveyance of the property, whichever occurs earlier, the seller shall, by separate written document, disclose to the purchaser the applicable special flood hazard area and X (shaded) flood zone designation(s).

      1.   The seller shall retain a copy of the disclosure document which has been signed by the purchaser acknowledging the date of receipt by the purchaser of the original document.

      2.   The information contained in the disclosure document must:

         a.   Be updated not less than once every six (6) months;

         b.   Advise the purchaser that the property may be subject to periodic flooding;

         c.   Advise the purchaser that the property is in an area having been identified as having special flood, mudslide, or flood-related erosion hazards and/or a moderate flood hazard; and

         d.   Provide the purchaser with instructions on how to obtain more information from the community development department regarding special flood hazard areas and the X (shaded) flood zone, flood insurance, and other available flood related resources. (Ord. 603, 11-1-2018; amd. Ord. 607, 9-19-2019)

   A.   Authority: The Board shall hear and decide appeals and requests for variances from the requirements of this chapter.

   B.   Appeals:

      1.   The Board shall hear and decide appeals when it is alleged there is an error in any requirement, decision or determination made by the Floodplain Administrator of this chapter.

      2.   Those aggrieved by the decision of the Board may appeal such decision to the appropriate court as provided in Nevada Revised Statutes.

   C.   Variances:

      1.   Application For Variance: In passing upon such applications, the Board shall consider all technical evaluations, all relevant factors, standards specified in other sections of this chapter, and:

         a.   The danger that materials may be swept onto other lands to the injury of others;

         b.   The danger to life and property due to flooding or erosion damage;

         c.   The susceptibility of the proposed facility and its contents to flood damage and the effect of such damage on the individual owner;

         d.   The importance of the services provided by the proposed facility to the community;

         e.   The necessity to the facility of a waterfront location, where applicable;

         f.   The availability of alternative locations for the proposed use which are not subject to flooding or erosion damage;

         g.   The compatibility of the proposed use with existing and anticipated development;

         h.   The relationship of the proposed use to the comprehensive plan and floodplain management program for that area;

         i.   The safety of access to the property in times of flood for ordinary and emergency vehicles;

         j.   The expected heights, velocity, duration, rate of rise and sediment transport of the floodwaters and the effects of wave action, if applicable, expected at the site; and

         k.   The costs of providing governmental services during and after flood conditions, including maintenance and repair of public utilities and facilities such as sewer, gas, electrical and water system and streets and bridges.

      2.   Conditions May Be Imposed: Upon consideration of the factors of subsection C1 of this section and the purposes of this chapter, the Board may attach such conditions to the granting of variances as it deems necessary to further the purposes of this chapter.

      3.   Standards For Granting Variances:

         a.   Generally, the only condition under which a variance from the elevation standard may be issued is for new construction and substantial improvements to be erected on a lot of one-half (1/2) acre or less in size contiguous to and surrounded by lots with existing structures constructed below the base flood level, providing items in subsections C1a through C1k of this section have been fully considered. As the lot size increases, the technical justification required for issuing the variance increases.

         b.   Variances may be issued for the rehabilitation or restoration of historic structures.

         c.   Variances shall not be issued within any designated floodway if any increase in flood levels during the base flood discharge would result.

         d.   Variances shall only be issued upon determination that the variance is the minimum necessary, considering the flood hazard to afford relief.

         e.   Variances shall only be issued upon:

            (1)   A showing of good and sufficient cause such as renovation, rehabilitation or reconstruction. Variances issued for economic considerations, aesthetics or because variances have been used in the past are not good and sufficient cause;

            (2)   A determination that failure to grant the variance would result in exceptional hardship to the applicant; and

            (3)   A determination that the granting of a variance will not result in increased flood heights, additional threats to public safety, extraordinary public expense, create nuisances, cause fraud on or victimization of the public or conflict with existing local laws or ordinances.

         f.   Variances, as interpreted in the national flood insurance program, are based on the general zoning law principle that they pertain to a physical piece of property, they are not personal in nature and do not pertain to the structure, its inhabitants, economic or financial circumstances. They primarily address small lots in densely populated residential neighborhoods. As such, variances from the flood elevations should be quite rare.

         g.   Variances may be issued for nonresidential buildings in very limited circumstances to allow a lesser degree of flood-proofing than watertight or dry flood-proofing, where it can be determined that such action will have low damage potential, complies with all other variance criteria except subsection C3a of this section and otherwise complies with subsections 15.800.12A and B of this chapter.

      4.   Notice When Variance Granted: Any applicant to whom a variance is granted shall be given written notice that the structure will be permitted to be built with a lowest floor elevation below the base flood elevation and that the cost of flood insurance will be commensurate with the increased risk resulting from the reduced lowest floor elevation.

   D.   Records And Reports: The County Clerk shall maintain the records of all appeal actions and report any variances to the Federal Emergency Management Agency upon request. (Ord. 603, 11-1-2018)

National flood insurance program regulations provide procedures to remove property from the 100-year floodplain or from a special flood hazard area. Amendments and revisions to community flood insurance rate maps cannot adversely impact the floodplain or floodway delineations of the level of the 100-year flood.

There are several procedures provided whereby the Federal Insurance Administrator will review information from the community, an owner, or a lessee of property where it is believed the property should not be included in a special flood hazard area.

Submissions to FEMA for revisions to effective flood insurance studies (FISs) by individual and community requesters will require the signing of application/certification forms. These forms will provide FEMA with assurance that all pertinent data relating to the revision is included in the submittal. They will also assure that: a) the data and methodology are based on current conditions; b) qualified professionals have assembled data and performed all necessary computations; and c) all individuals and organizations impacted by proposed changes are aware of the changes and will have an opportunity to comment on them. FEMA procedures permit the following types of request:

A request for a revision to the effective FIS information (FIRM, FBFM, and/or FIS report) is usually a request that FEMA replace the effective floodplain boundaries, flood profiles, floodway boundaries, etc., with those determined by the requester. Before FEMA will replace the effective FIS information with the revised, the requester must: a) provide all of the data used in determining the revised floodplain boundaries, flood profiles, floodway boundaries, etc.; b) provide all data necessary to demonstrate that the physical modifications to the floodplain have been adequately designed to withstand the impacts of the one percent (1%) annual chance flood event and will be adequately maintained; c) demonstrate that the revised information (e.g., hydrologic and hydraulic analyses and the resulting floodplain and floodway boundaries) is consistent with the effective FIS information.

Requests for amendments or revisions to FEMA maps must be reviewed and submitted to FEMA by the Board with the applicant for a map amendment or revision required to prepare all the supporting information and appropriate FEMA forms.

The scientific or technical information to be submitted with these requests may include, but is not limited to, the following:

   A.   An actual copy of the recorded plat map bearing the seal of the appropriate recordation official County Clerk or Recorder of Deeds indicating the official recordation and proper citation, deed or plat book volume and page number, or an equivalent identification where annotation of the deed or plat book is not the practice.

   B.   A topographical map showing:

      1.   Ground elevation contours in relation to the North American Vertical Datum (NAVD) 1988 or the National Geodetic Vertical Datum (NGVD) 1927 (MSL).

      2.   The total area of the property in question.

      3.   The location of the structure or structures located on the property in question.

      4.   The elevation of the lowest adjacent grade to a structure or structures.

      5.   An indication of the curvilinear line which represents the area subject to inundation by a base flood. The curvilinear line should be based upon information provided by an appropriate authoritative source, such as a Federal agency, Department of Water Resources, a County Water Control District, a County or city engineer, a Federal Emergency Management Agency flood insurance study, or a determination by a registered professional engineer.

   C.   A copy of the FHBM or FIRM indicating the location of the property in question.

   D.   A certification by a Nevada licensed professional engineer or Nevada licensed land surveyor that the lowest grade adjacent to the structure is above the base flood elevation.

   E.   The completion of the appropriate forms in the Federal Emergency Management Agency's packets, amendments and revisions to national flood insurance program maps (MT-1 FEMA form 81-87 series and MT-2 FEMA form 81-89 series).

   F.   The applicant shall provide the proposed map revision to the Floodplain Administrator in form and format compatible with the County geographical information system (GIS). The scale of the plan, improvements, monuments and other items shall be in model space correctly oriented to coordinate system as established by the GIS coordinator. (Ord. 603, 11-1-2018; amd. Ord. 607, 9-19-2019)

The degree of flood protection required by this chapter is considered reasonable for regulatory purpose and is based on available information derived from scientific and engineering methods of study. Larger floods can and will occur on rare occasions. Flood heights may be increased by manmade or natural causes. This chapter does not imply that land outside the areas of special flood hazards and X (Shaded) flood zones or uses permitted within such areas will be free from flooding or flood damages. This chapter shall not create liability on the part of Lyon County or any officer or employee thereof or the Federal Insurance Administration or the Federal Emergency Management Agency for any flood damages that result from reliance on this chapter or any administrative decision lawfully made hereunder. (Ord. 603, 11-1-2018; amd. Ord. 607, 9-19-2019)