N.J. Admin. Code § 7:13-3.2

Current through Register Vol. 56, No. 11, June 3, 2024

Section 7:13-3.2 - Selecting a method for determining the flood hazard area and floodway along a regulated water

(a) There are a number of factors that influence the selection of a method for determining the flood hazard area and floodway on a given site, as set forth in (b) through (e) below. These factors include the existence of a Department delineation or FEMA flood mapping, whether the applicant prefers to calculate the flood hazard area and/or floodway limits, and what type of project is proposed. Furthermore, each method has certain limitations on its usefulness and availability as described in this subchapter. Applicants are encouraged to carefully review the entire subchapter before selecting a method.

(b) Where a Department delineation for a regulated water has been promulgated on or after January 24, 2013, an applicant shall determine the flood hazard area and floodway limits using this delineation in accordance with Method 1, as set forth at 7:13-3.3.

(c) Where a Department delineation for a regulated water has been promulgated prior to January 24, 2013, an applicant may:

1. Determine the flood hazard area and/or floodway in accordance with (c)1i or ii below, whichever results in a higher flood hazard area design flood elevation and wider floodway limit:

i. The Department delineation described in (c) above, in accordance with Method 1, as set forth at 7:13-3.3; or

ii. FEMA flood mapping, in accordance with Method 2 in a tidal flood hazard area or Method 3 in a fluvial flood hazard area, as set forth at 7:13-3.4(d) and (e), respectively; or

2. Determine the flood hazard area and/or floodway by calculation, in accordance with either of the following, as appropriate:

i. Method 4, as set forth at 7:13-3.4(f), provided the flow rate used to determine the flood hazard area design flood elevation and floodway limit is no less than the flow rate used to determine the flood hazard area design flood elevation and floodway limit under the Department delineation described in (c)1 above, in accordance with Method 1, as set forth at 7:13-3.3; or

ii. Method 6, as set forth at 7:13-3.6.

(d)Where no Department delineation exists for a regulated water, an applicant may:

1. Determine the flood hazard area and/or floodway using FEMA flood mapping, provided such mapping exists for the section of regulated water in question, in accordance with Methods 2, 3, or 4, as set forth at 7:13-3.4(d), (e), and (f), respectively;

2. Determine the approximate limit of the flood hazard area in accordance with Method 5, as set forth at 7:13-3.5, provided no FEMA flood mapping exists for the section of regulated water in question; or

3. Determine the flood hazard area and/or floodway by calculation, in accordance with Method 6, as set forth at 7:13-3.6.

(e) The flood hazard area and floodway shall be determined using only one method for each regulated water on a site, except in the following cases:

1. Where a Department delineation or FEMA flood mapping terminates within a site, the flood hazard area on the remainder of the site may be delineated using another applicable method described in this subchapter; and

2. Where Method 3 is used to delineate the flood hazard area but FEMA flood mapping does not provide a floodway limit for the section of regulated water in question, and determining the floodway limit is necessary to demonstrate compliance with the requirements of this chapter, the applicant shall use Method 4 to calculate the floodway limit.

N.J. Admin. Code § 7:13-3.2

Amended by 48 N.J.R. 1067(a), effective 6/20/2016