16.20.560 Frequently flooded areas.
(1) Classification.
(a) Frequently flooded areas shall be those floodways and associated floodplains designated by the Federal Emergency Management Agency (FEMA) flood hazard classifications as delineated on the most current available flood insurance rate maps for Grant County, or as subsequently revised by FEMA, as being within the 100-year floodplain, or those floodways and associated floodplains delineated by a comprehensive flood hazard management plan adopted by Grant County board of commissioners, as being within the 100-year floodplain. For the purpose of this chapter, in case of conflict between FEMA flood hazard maps and the comprehensive flood hazard management plan designations, the more restrictive designation shall apply.
(2) Maps and References.
(a) Administrator shall use the following maps and references to assist in making a determination pursuant to ECMC 16.20.500(9):
(i) FEMA flood insurance rate maps (FIRM), most current available.
(3) Development Standards.
(a) In addition to the general provisions of these regulations and the requirements of the underlying zoning district, the following minimum standards shall apply to development activities within and adjacent to frequently flooded areas:
(i) All development within frequently flooded areas shall comply with the Grant County flood damage and prevention ordinance (Chapter 24.16 GCC) regarding structural safeguards to reduce risk to human life, health and property from flooding, and other pertinent ordinances and codes.
(ii) Any use or development shall not alter the normal movement of surface water in a manner that would cause the unnatural diversion of floodwater to otherwise flood-free areas.
(iii) Where frequently flooded areas coincide with other designated critical areas, critical areas reports and mitigation plans shall address any combined functions and values.
(iv) Filling and grading in frequently flooded areas shall occur only upon a determination by a qualified professional that the filling or grading will not increase flood hazards to others.
(v) Subdivision in frequently flooded areas is subject to the following standards:
(A) All lots created shall have adequate building space outside flood hazard areas, including the floodway, 100-year floodplain, and channel migration zones;
(B) Plat maps shall indicate the floodway and the 100-year floodplain;
(C) Subdivisions shall be designed to minimize or eliminate the potential for flood damage; and
(D) Subdivisions shall provide for stormwater drainage, in accordance with city standards, so as to reduce exposure to flood hazards.
(vi) Bank Stabilization Projects. Where consistent with other regulations and with the flood hazard reduction plan, protection of structures, public roadways or sole access routes in existence before the effective date of this chapter shall be allowed. Such projects shall be designed to minimize adverse impacts to property, public improvements, and ecological functions.
(vii) Utilities shall be located above the base flood elevation (BFE), preferably three or more feet.
(viii) All new construction and substantial improvements shall be constructed using flood resistant materials and using methods and practices that minimize flood damage.
(ix) All new construction and substantial improvements shall be anchored to prevent flotation, collapse, or lateral movement of the structure.
(x) No rise in the BFE shall be allowed. Post and piling techniques are preferred and are presumed to produce no increase in the BFE.
(xi) Modification of stream channels shall be avoided. (Ord. 484 § 2, 2014)