N.J. Admin. Code § 7:7-12.7

Current through Register Vol. 56, No. 24, December 18, 2024

Section 7:7-12.7 - New dredging

(a) New dredging is the removal of sediment that does not meet the definition of maintenance dredging at N.J.A.C. 7:7-12.6 or the definition of environmental dredging at N.J.A.C. 7:7-12.8. The temporary or permanent displacement or removal of sediment for the purpose of installing submerged pipelines and cables is considered new dredging.

(b) New dredging and the management of the dredged material shall be conducted in accordance with Appendix G.

(c) New dredging is conditionally acceptable in all general water areas for boat moorings, navigation channels, anchorages, or submerged cable or pipelines provided:

1. There is a demonstrated need that cannot be satisfied by existing facilities;

2. The facilities served by the new dredging satisfy the location requirements for special water's edge areas;

3. The adjacent water areas are currently used for recreational boating, commercial fishing or marine commerce;

4. The dredge area causes no significant disturbance to special water or water's edge areas;

5. The adverse environmental impacts are minimized to the maximum extent feasible;

6. The dredge area is reduced to the minimum practical;

7. The maximum depth of the newly dredged area shall not exceed that of the connecting access or navigation channel necessary for vessel passage to the bay or ocean;

8. The new dredging will have no adverse impacts on groundwater resources;

9. No dredging shall occur within 10 feet of any wetlands. The proposed slope from this 10 foot buffer to the nearest edge of the dredged area shall not exceed three vertical to one horizontal; and

10. The new dredging shall be accomplished consistent with all of the following conditions, as appropriate to the dredging method:

i. An acceptable dredged material placement site with sufficient capacity will be used. (See N.J.A.C. 7:7-12.9, Dredged material disposal in water areas, and N.J.A.C. 7:7-15.12, Dredged material placement on land.). The Department will make an acceptable use determination for the beneficial use of dredged material in accordance with Appendix G;

ii. Pre-dredging chemical and physical analysis of the dredged material, including water quality predictive analyses for surface water and ground water may be required where the Department suspects contamination of sediments. Additional testing, such as bioaccumulation and bioassay testing of sediments, may also be required as needed to determine the acceptability of the proposed placement site for the dredged material. The results of these tests will be used to determine if contaminants may be resuspended at the dredging site and what methods may be needed to control their escape. The results will also be used to determine acceptability of the proposed dredged material placement method and site;

iii. Turbidity concentrations (that is, suspended sediments) and other water quality parameters at, downstream, and upstream of the dredging site, and discharges from dredged material management areas (see N.J.A.C. 7:7-9.49) shall meet applicable Surface Water Quality Standards at N.J.A.C. 7:9B. The Department may require the permittee to conduct biological, physical, and chemical water quality monitoring before, during, and after dredging and disposal operations to ensure that water quality standards are not exceeded;

iv. If predicted water quality parameters are likely to exceed Surface Water Quality Standards at N.J.A.C. 7:9B, or Ground Water Quality Standards at N.J.A.C. 7:9C, or if pre-dredging chemical analysis of dredged material, including surface water and ground water quality predictive analyses, reveals significant contamination, then the Department will work cooperatively with the applicant to fashion acceptable control measures and will impose seasonal restrictions under the specific circumstances identified at (b)10vii below;

v. For new dredging using mechanical dredges deploying silt curtains at the dredging site may be required, if feasible based on site conditions as provided in Appendix G. Where the use of silt curtains is infeasible, dredging using closed watertight buckets or lateral digging buckets may be required. The Department may also require the use of additional best management practices when highly contaminated sediments are to be dredged;

vi. For hydraulic dredges, specific operational procedures designed to minimize water quality impacts, such as removal of the cutter head, flushing of pipeline sections prior to disconnection, or limitations on depth of successive cuts, may be required;

vii. The Department may authorize dredging on a seasonally restricted basis only, in waterways characterized by the following:

(1) Known spawning, wintering or nursery areas of shortnose sturgeon, winter flounder, Atlantic sturgeon, alewife, blueback herring, striped bass or blue crab;

(2) Water bodies downstream of known anadromous fish spawning sites under N.J.A.C. 7:7-9.5, Finfish migratory pathways, where the predicted turbidity plume will encompass the entire cross-sectional area of the water body, thus forming a potential blockage to upstream migration;

(3) Areas of contaminated sediments with high levels of fecal coliform and/or streptococcus bacteria, and/or hazardous substances adjacent to (upstream or downstream) State approved shellfishing waters and public or private bathing beaches; or

(4) Areas within 1,000 meters or less of oyster beds as defined in N.J.A.C. 7:7-9.2; and

viii. Side slopes shall not be steeper than three vertical to one horizontal adjacent to wetlands to prevent undermining and/or sloughing of the wetlands.

(d) Propwash dredging, which is the movement of sediment by resuspending accumulated material by scouring the bottom with boat propellers or specially designed equipment with propellers, is prohibited.

(e) New dredging or excavation to create new lagoons for residential development is prohibited in wetlands, N.J.A.C. 7:7-9.27, wetlands buffers, N.J.A.C. 7:7-9.28, and endangered or threatened wildlife or plant species habitats, N.J.A.C. 7:7-9.36, and discouraged elsewhere.

(f) New dredging is conditionally acceptable to control siltation in lakes, ponds and reservoirs, provided that an acceptable sedimentation control plan is developed to address re-sedimentation of these water bodies.

(g) With the exception of (c), (e), and (f) above, new dredging is discouraged.

(h) Rationale: New dredging is performed to create new or expand existing navigation or access channels, marinas, lagoons, canals, or boat moorings, or to make these areas accessible to ships of deeper draft. New dredging is also performed as part of the installation of some submerged pipelines and cables.

New dredging is sometimes necessary if water dependent elements of New Jersey's economy are to expand, but as with maintenance dredging, special areas and other environmentally sensitive areas must not be unnecessarily disturbed.

New and maintenance dredging are similar in their potential water quality and biological impacts. The additional impacts associated with new dredging are permanent physical changes in water depth, circulation, and sediment types. Dredged areas which are deeper than surrounding waters or deeper than connecting channels are known to have seasonally anoxic (devoid of oxygen) bottom waters. This results from poor vertical mixing and/or lateral circulation, formation of a thermocline (static cool bottoms waters unable to mix vertically) and biochemical exhaustion of dissolved oxygen. Benthic organisms and finfish cannot survive in anoxic waters.

Propwash dredging is indiscriminate, releasing sediment into the water column with no control to minimize impacts on water quality, or control the fate of the resuspended sediment. Sediment resuspended in this manner could smother shellfish beds, submerged vegetation habitats, and result in the loss of navigability in adjacent berths and channels. Therefore propwash dredging is prohibited under these rules.

The ecological values of intertidal and subtidal shallows are summarized in N.J.A.C. 7:7-9.15. These ecological values will be weighed against loss of this habitat in comparison to the public value to be served by the new dredging.

New dredging for the installation of submerged pipelines or cables is conditionally acceptable provided the dredging complies with the conditions of this section, the general water area rule specific to the project and the energy facility use rule, where applicable.

N.J. Admin. Code § 7:7-12.7

Renumbered from 7:7E-4.7 by 47 N.J.R. 1392(a), effective 7/6/2015