[Code of Federal Regulations] [Title 40, Volume 21] [Revised as of July 1, 2002] From the U.S. Government Printing Office via GPO Access [CITE: 40CFR258.11] [Page 394-395] TITLE 40--PROTECTION OF ENVIRONMENT CHAPTER I--ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PART 258--CRITERIA FOR MUNICIPAL SOLID WASTE LANDFILLS--Table of Contents Subpart B--Location Restrictions Sec. 258.11 Floodplains. (a) Owners or operators of new MSWLF units, existing MSWLF units, and lateral expansions located in 100-year floodplains must demonstrate that the unit will not restrict the flow of the 100-year flood, reduce the temporary water storage capacity of the floodplain, or result in washout of solid waste so as to pose a hazard to human health and the environment. The owner [[Page 395]] or operator must place the demonstration in the operating record and notify the State Director that it has been placed in the operating record. (b) For purposes of this section: (1) Floodplain means the lowland and relatively flat areas adjoining inland and coastal waters, including flood-prone areas of offshore islands, that are inundated by the 100-year flood. (2) 100-year flood means a flood that has a 1-percent or greater chance of recurring in any given year or a flood of a magnitude equalled or exceeded once in 100 years on the average over a significantly long period. (3) Washout means the carrying away of solid waste by waters of the base flood.