R 560.304 Building in areas affected by floodplains.

Rule 304. (1) The purpose of this rule is to prescribe minimum standards for a new development for residential purposes and occupancy within or affected by a floodplain. (2) A proprietor shall file and record with the final plat restrictive deed covenants that state, in perpetuity, that no filling or occupation of the floodplain area will be allowed without approval of the department of environmental quality and that any building used or capable of being used for residential purposes and occupancy within or affected by the floodplain shall comply with all of the following requirements: (a) Be located on a lot having a minimum buildable site of 3,000 square feet of its area at its natural grade above the elevation of the line defining the floodplain limits. The buildable site shall exclude all setbacks and easements. (b) Be served by streets within the proposed subdivision having surfaces not lower than 1 foot below the elevation defining the floodplain limits. (c) Have lower floors, excluding basements, not lower than the elevation defining the floodplain limits. (d) Have openings into the basement not lower than the elevation defining the floodplain limits. (e) Have basement walls and floors, if below the elevation defining the floodplain limits, that are watertight and designed to withstand hydrostatic pressures from a water level equal to the elevation of the contour defining the floodplain limits following methods and procedures outlined in chapter 5 for type A construction and chapter 6 for class 1 loads found in the publication entitled "Flood Proofing Regulations," EP 1165 2 314, prepared by the office of the chief of engineers, United States Army, Washington, DC, March 1992. Figure 6 on page 14-5 of the regulations shows typical foundation drainage and waterproofing details. This document is adopted by reference in these rules and is available, at no cost, from the Department of Environmental Quality, Land and Water Management Division, P.O. Box 30458, Lansing, Michigan 48909-7958, or the Department of the Army, Corps of Engineers, Publications Depot, 890 S. Pickett, Alexandria, Virginia 22304. (f) Be equipped with a positive means of preventing sewer backup from sewer lines and drains that serve the building. (g) Be properly anchored or weighted to prevent flotation. (3) The requirement that the building site have its natural grade above the floodplain limit in subrule (2) (a) of this rule may be waived if the building site is to be filled, the requirements of section 194(c) of the act and sections 3104, 3105, 3106, 3107, and 3108 of part 31 of Act No. 451 of 1994, being §§324.3104, 324.3105, 324.3106, 324.3107, and 324.3108 of the Michigan Compiled Laws, sections 30102 and 30106 of part 301 of Act No. 451 of the Public Acts of 1994, being §§324.30102 and 324.30106 of the Michigan Compiled Laws, and sections 30304 and 30311 of part 303 of Act No. 451 of the Public Acts of 1994, being §§324.30304 and 324.30311 of the Michigan Compiled Laws, where applicable, are met, and any 1 of the following occurs: (a) The lowest floor, including the basement, will be constructed above the 100- year floodplain elevation. (b) A licensed professional engineer schooled in the science of soil mechanics states all of the following: (i) That the building site has been filled with soil of a type and in a manner that hydrostatic pressures are not exerted upon the basement walls or floor while the watercourse is at or below the 100-year flood elevation. (ii) That the placement of the fill will prevent settling of the building or buckling of floors or walls. (iii) That the building is equipped with a positive means of preventing sewer backup from sewer lines and drains that serve the building. (c) A licensed professional engineer or architect certifies all of the following: (i) That the basement walls and floors are designed to be watertight and to withstand hydrostatic pressure from a water level equal to the 100-year flood elevation. (ii) That the building is properly anchored or weighted to prevent flotation. (iii) That the building is equipped with a positive means of preventing sewer backup from sewer lines and drains that serve the building. (4) If the natural floodplain area is altered through the placement of fill or the watercourse is relocated or enclosed and the community within which the subdivision is located is a participant in the national flood insurance program, then the developer shall apply for and receive a letter of map revision based on fill from the federal emergency management agency before recording the final plat.