All land lying below certain control elevation (United States Geological Survey datum) as shown on the Zoning Map shall be considered wetlands, deemed to be subject to seasonal or periodic flooding. And all special flood hazard areas within the Town of Littleton designated as Zone A and AE on the Middlesex County Flood Insurance Rate Map (FIRM) issued by the Federal Emergency Management Agency (FEMA) for the administration of the National Flood Insurance Program, shall be considered floodplains. The map panels of the Middlesex County FIRM that are wholly or partially within the Town of Littleton are panel numbers 25017C0209E, 25017C0216E, 25017C0217E, 25017C0218E, and 25017C0228E, dated June 4, 2010; and 25017C0219F, 25017C0236F, 25017C0237F, 25017C0238F, 25017C0239F, 25017C0241F, and 25017C0243F, dated July 7, 2014. The exact boundaries of the floodplain may be defined by the one-hundred-year base flood elevations shown on the FIRM and further defined by the Middlesex County Flood Insurance Study (FIS) report, dated July 7, 2014. The FIRM and FIS report are incorporated herein by reference and are on file with the Building Inspector. Within Zone A, where the base flood elevation is not provided on the FIRM, the applicant shall obtain any existing flood elevation data, which shall be reviewed by the Building Inspector or the Board of Appeals for its reasonable use toward meeting the requirements of this chapter.

In any area designated wetland or floodplain under § 173-72, the permitted uses and the requirements of the underlying zoning district shall continue to apply, except that the following shall also apply: a special permit by the Board of Appeals is required for any new structure, for additions of 10% or more to the ground-floor area of any building existing at the time of adoption of this section or for repairs or alterations totaling 75% or more of the actual cash value of the structure before initial improvement or, if damaged, before the damage occurred for any construction or development, whether or not falling within the above requirements for a special permit, which in the opinion of the Building Inspector can be presumed hazardous as defined in § 173-74 below.

Without limiting the generality of the foregoing, the following are presumed to be hazardous to the health or safety within wetlands and are among the criteria for the Board of Appeals' determination for floodplains as required under § 173-73.B and § 173-73.C above:

In a riverine situation, the Building Commissioner or Board of Appeals shall notify the following of any alteration or relocation of a watercourse:

Such permit shall be issued only upon confirmation that the procedural requirements of the Wetlands Act of the Massachusetts General Laws (MGL C. 131, §§ 40 and 40A) will be met.