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Streams & Rivers - The Flood Hazard Area Control Act
- Application Requirements
- Determining the Flood Hazard Area and Floodway
- Determining the Riparian Zone
When obtaining an individual permit or general permit, it is often necessary to know the limits of the flood hazard area, floodway, and/or riparian zone. When those limits are unknown, such as along a watercourse that has no available floodplain mapping, a verification can be used to determine those limits.
A verification is a document containing the Department's approval of the flood hazard area design flood elevation on a site, includes either a flood hazard area limit or an indication that the entire site is in a flood hazard area, and may also include a floodway limit and/or a riparian zone limit, if applicable. There are six methods acceptable for use in determining the flood hazard area and floodway (see N.J.A.C. 7:13-3), and three possible riparian zone widths (See N.J.A.C. 7:13-4). A verification is issued in accordance with the standards in N.J.A.C. 7:13-5. See the “Forms and Checklists” page of this website for the verification application checklist.
Please be aware that in some cases a verification is required prior to or concurrent with a permit application. Generally, a verification is not required when applying for an applicability determination, or a general permit-by-certification or conducting work under a permit-by-rule. When applying for an individual permit or general permit, a verification may be required. The cases where a verification is or is not required prior to or concurrent with an individual or general permit application are explained at N.J.A.C. 7:13-5.5.
An application for a verification shall include the following:
- Three copies of an application report, as described at N.J.A.C. 7:13-15.3. If a hydrologic and/or hydraulic model is submitted with the application, the photographs required in the application report shall depict any water control structures, as well as a representative sampling of the locations of any cross-sections, which are referenced by the models;
- One copy of an engineering report, as described at N.J.A.C. 7:13-15.4, which includes all necessary supporting calculations, maps and other documentation and a description of which delineation method under N.J.A.C. 7:13-3 was used;
- Documentation that the applicable public notice requirements of N.J.A.C. 7:13-16 have been met;
- The appropriate application fee required at N.J.A.C. 7:13-17; and
- Six sets of drawings, signed and sealed by an engineer, land surveyor or architect, as appropriate, which include the following:
- Topography that references NGVD, or includes the appropriate conversion factor to NGVD, unless the applicant demonstrates that such reference is not necessary;
- The limit of the flood hazard area under existing conditions on the site. If the entire site is in a flood hazard area, the drawings shall include a note to this effect, as well as the elevation(s) of the flood hazard area design flood on the site;
- The limit of any floodway under existing conditions on the site, if the applicant seeks verification of the floodway limits. If the entire site is in a floodway, the drawings shall include a note to this effect;
- A metes and bounds description of any flood hazard area limit and floodway limit under existing conditions onsite. If the verification is submitted concurrently with a permit application that proposes to affect one or both of these limits, the drawings shall also include a metes and bounds description of the proposed flood hazard area and/or floodway limits;
- The following statement: "NOTE: All or a portion of this site lies in a flood hazard area. Certain activities in flood hazard areas are regulated by the New Jersey Department of Environmental Protection and some activities may be prohibited on this site or may first require a permit. Contact the Division of Land Use Regulation at (609) 292-0060 for more information prior to any construction onsite.";
- A note indicating which method described at N.J.A.C. 7:13-3 was used to determine the limit of the flood hazard area and/or floodway;
- The limit of any riparian zone onsite as described at N.J.A.C. 7:13-4.1; and
- An indication of the location of any cross-section and water control structure referenced in the engineering report as well as a graphic depiction of each cross-section.
This method is used when a Department delineation exists along the watercourse. A list of Department delineations is available in appendix 2 of the Flood Hazard Area Control Act Rules (N.J.A.C. 7:13). The Flood Hazard Area Elevation and the Floodway are taken directly from the available mapping under this method.
This method is used when the watercourse in question is tidal and has available FEMA mapping that shows the 100-year tidal flood elevation. Under this method, the tidal 100-year flood elevation and the floodway are taken directly from the FEMA mapping. If a floodway is not shown, it is assumed to be at the top of bank for linear waterways. If a 100-year flood elevation is not shown, this method cannot be used.
This method is used when the watercourse in question is fluvial and has available FEMA mapping that shows the 100-year fluvial flood elevation. Under this method the floodway is taken directly from the available mapping and one foot is added to the 100-year flood elevation. If a floodway is not shown on the mapping, it could be left unknown if not needed or must be calculated using method 4. It cannot be assumed to be at the top of bank under this method. If the 100-year flood elevation is not shown, this method cannot be used.
This method is generally only used when the applicant wishes to compare pre and post condition water surface elevations, such as for the construction of a bridge. In tidal areas, the 100-year FEMA flowrate is used directly (BOB REMOVE THE COMMA) and in fluvial areas the FEMA 100-year flowrate + 25% is used. If no FEMA 100-year flowrate is available, this method cannot be used.
This method is conservative and is used to approximate an unknown flood hazard area. However, since the determination is approximate is can only be used in certain circumstances, which are outlined at N.J.A.C. 7:13-9.7. The details of this method are available in appendix 1 of the Flood Hazard Area Control Act Rules (N.J.A.C. 7:13).
Under this method the applicant calculates the flood hazard area and floodway using hydrologic and hydraulic calculations. This method can be used under all circumstances, except where a Department delineation for a regulated water has been promulgated on or after January 24, 2013. In such a case the applicant must use that Department delineation under method 1. The specific methods of calculation under this method must follow Division accepted methodology. The use of the DelMarVa unit hydrograph should be limited to stormwater runoff calculations where appropriate and should not be used for floodplain delineation under this method.
A riparian zone is the land and vegetation within and adjacent to a regulated water. A riparian zone exists along every regulated water, except there is no riparian zone along the Atlantic Ocean nor along any manmade lagoon, stormwater management basin, or oceanfront barrier island, spit or peninsula. When determining the limits of the riparian zone on-site, there are two steps. First, you must determine the riparian zone width. Second, you must determine from where to measure that width.
Determining the Riparian Zone Width
The width of the riparian zone along each regulated water on-site is as follows:
- The riparian zone is 300 feet wide along both sides of any Category One water, and all upstream tributaries situated within the same HUC-14 watershed;
- The riparian zone is 150 feet wide along both sides of the following waters not identified in 1 above:
- Any trout production water and all upstream waters (including tributaries);
- Any trout maintenance water and all upstream waters (including tributaries) within one linear mile as measured along the length of the regulated water;
- Any segment of a water flowing through an area that contains documented habitat for a threatened or endangered species of plant or animal, which is critically dependent on the regulated water for survival, and all upstream waters (including tributaries) within one linear mile as measured along the length of the regulated water; and
- Any segment of a water flowing through an area that contains acid producing soils; and
- The riparian zone is 50 feet wide along both sides of all waters not identified in 1 or 2 above.
Determining How the Riparian Zone is Measured
The riparian zone is measured landward from the top of bank where a discernible bank is present. However, if a discernible bank is not present the following standards apply:
- Along a linear fluvial or tidal water, such as a stream, the riparian zone is measured landward of the feature's centerline;
- Along a non-linear fluvial water, such as a lake or pond, the riparian zone is measured landward of the normal water surface limit;
- Along a non-linear tidal water, such as a bay or inlet, the riparian zone is measured landward of the mean high water; and
- Along an amorphously-shaped feature, such as a wetland complex, through which a regulated water flows but which lacks a discernible channel, the riparian zone is measured landward of the feature's centerline.