Re: Higbee Beach WMA Proposed Restoration Project. 1. Saltwater Intrusion Studies:

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3 NJDEP - Office of Natural Resource Restoration Response to Comments and Questions Dated April 25, 2018 Cape May Point Borough Environmental Commissioner Re: Higbee Beach WMA Proposed Restoration Project 1. Saltwater Intrusion Studies: There have been several comprehensive studies conducted by USGS, NJDEP and DOI to improve the understanding of the natural and human-related factors that govern saltwater intrusion into Cape May County aquifers. These studies included extensive investigation of Cape Island aquifer(s), including the Holly Beach waterbearing zone, which is the open aquifer I believe you are referring to in your comment. Reports on two of the most comprehensive studies can be found at the following links: A portion of the Holly Beach waterbearing zone extends beneath the Pond Creek saltmarsh. As discussed in the studies noted above, the Holly Beach waterbearing zone is a shallow unconfined aquifer that receives freshwater recharge from precipitation. However, where the waterbearing zone is overlain by soil that is periodically saturated by saltwater, freshwater infiltration is minimal if at all. Under existing conditions, the Pond Creek marsh is being partially inundated by the tides on a daily basis and is fully inundated during extreme high tides. However, as discussed in Response 5 below, the installation of the proposed berm will limit the extent of tidal inundation and will increase the area of freshwater recharge to the Holly Beach waterbearing zone. 2. Daveys Lake Salinity: Salinity testing on Daveys Lake was conducted as part of the baseline studies needed to inform the restoration design. Salinity ranged between 7 and 15 parts per thousand. The higher readings occurred after storm events which we believe resulted in tides that breached low spots in the existing dunes. These low spots will be closed by additional dune structures that will be constructed as part of the restoration. Post-restoration monitoring will include continued salinity monitoring of Daveys Lake and all other freshwater habitats being protected from saltwater inundation as a result of the restoration. 3. Plans for Dune Construction: There are no plans for the construction of dunes that would be integrated with Cape May Point s dunes. Dune construction will be for the purpose of protecting Daveys Lake and as part of upland restoration on the former Magnasite plant site in locations where maritime forest habitat creation is proposed. 3. Maritime Forest Dunes: The proposed maritime forest areas are located on the former Magnasite plant site and are in no way connected with Cape May Point forested areas. Please see the attached plans showing location and construction details of the proposed dunes and maritime forest. Please also see the attached rendering of full design layout. 1

4 4. Berm Composition: The design purpose of the berm is to protect the existing freshwater wetlands from further intrusion of salt water (see Response 5 below) while managing potential flood risk to the upper watershed. Although the project is not a flood protection project, with the berm elevation set at 7.5 ft NAVD88, this elevation will actually reduce the current risk of tidal flooding to the freshwater wetlands and upper watershed. The material required to construct the berm will include soil aggregates (natural or prepared mixtures) consisting predominately of hard, durable particles of stone, gravel, sand, and some silt, with little clay, meeting the following requirements: Maximum grain size 1/2 inch in maximum 5 percent; Passing #4 sieve: percent; Passing #16 sieve: percent; Passing #50 sieve: 5-25 percent; Passing #200 percent 0-5 percent; ph: Between 5 10; Organic Content maximum 1.00 percent; Chloride: Less than 100 ppm; and Sulfates, as SO3: Less than 200 ppm. The following berm surface treatments will then be applied as shown in the figure below: To resist scouring, the design calls for the placement of a 15-inch thick riprap layer over the geotextile filter fabric along the slopes of the berm. The riprap will be well graded from a maximum size of at least 1.5 times the average rock size (D50) of 10 inches. To provide vegetated slopes and achieve habitat requirements, the riprap will then be covered with an additional geotextile fabric layer and covered with a layer of loose NJDOT I-8, followed by a layer of sand or topsoil. Along berm top, a 15-foot wide access road/trail will be constructed by placing 6 inches of compacted DGA and aggregate surface course. The final surface treatment entails planting vegetation to provide erosion control, habitat, and screening for wildlife viewing. Where maintenance ramps are designated in the construction plans, the berm will be constructed with compacted NJDOT I-8 material to 15 inches below proposed grade, lined with geotextile fabric, and covered with a 15-inch thick riprap layer as detailed above. 5. Freshwater Wetland Area: 2

5 There are over 283 acres of wetland habitat inside and outside the project area. Approximately 111 of those acres are wetlands that are inundated with saltwater on an infrequent basis (only during extreme high tides). The remaining 172 acres are tidal saltmarsh that have become degraded due to poor tidal hydrology. The Higbee Beach WMA restoration project will create/restore/enhance acres of wetlands within the project area. Following extensive efforts to first avoid and then minimize impacts to jurisdictional wetlands and open waters within the project area, the proposed project will permanently impact a total of approximately acres of wetlands and open waters. Of this total, approximately 6.78 acres of permanent impacts are to coastal wetlands, and 5.63 acres of permanent impacts are to freshwater wetlands (45% of total permanent disturbance). Impacts are to mainly Phragmites emergent wetlands and tidal emergent low marsh. Please see attached Table 14 for a detailed description of permanent wetland disturbances. To properly address the question of how many acres of freshwater will be created, it is important to first note that once the construction of the berm is completed, there will be a stabilizing effect on wetland habitat within the Higbee Beach WMA well beyond the boundaries of the project area. This will occur primarily in areas located east and south of the berm alignment. Since 1917, the inlet channel to Pond Creek marsh has been obstructed, resulting in negligible tidal exchange between Delaware Bay and Pond Creek, enabling the invasion of Phragmites and degradation of the marsh habitat. The further marsh habitat is away from the inlet channel, the lower the frequency of saltwater inundation there. This becomes evident as more and more of the upper reaches of the marsh become dominated by freshwater plant species. However, this primarily freshwater habitat remains exposed to potential saltwater inundation by an exceptional storm surge event. With the installation of the berm, the approximately 111 acres currently subject to intermittent saltwater intrusion during large storm surge events will be permanently protected from such events and in time allowed to fully transition into freshwater wetland habitat. Thus, the restoration project will effectively be creating and/or enhancing a minimum of 111 additional acres of freshwater wetlands. 6. Offsite Removal of materials: There will be no excavated material removed from the site. All material being excavated has been approved for reuse on site in connection with the restoration. However, there will be some demolition debris (metal, wood,etc.) and construction debris removed from the site for recycling and/or disposal. 7. Pond Creek Watershed Studies: All studies (baseline studies) that were needed for permitting and design purposes focused primarily on areas within the project boundary which did not include the entire watershed. However the area of the complete/entire watershed was determined for design and hydraulic/hydrologic modeling purposes. 8. Administrative Note on Trucks Delivering Sand: NJDOT has been notified that a number of residences have observed trucks traveling Sunset Boulevard without covers over their loads. Please notify me if this continues to be observed by residences. 3

6 Higbee Beach Wetland Restoration Project Wetland Type Coastal Wetland Freshwater Wetland Table 14. Permanent Wetland Impacts by Habitat Type Existing Habitat Permanent wetland Proposed Habitat Type Type impacts Forested Wetland Open Water/Channel Phragmites Emergent Wetland Tidal Emergent (Low Marsh) Berm - Old Field/Early Successional Field <0.01 Berm - Non Vegetative Berm 0.03 Berm - Upland Shrubland 0.06 Open Water/Channel 0.01 Maritime Forest/Dune 0.05 Tidal Emergent (High Marsh) 0.20 Tidal Emergent (Low Marsh) <0.01 Berm - Old Field/Early Successional Field 0.03 Berm - Non Vegetative Berm 0.03 Berm - Upland Shrubland 0.01 Rip Rap 0.04 Berm - Old Field/Early Successional Field 1.19 Berm - Upland Shrubland 0.99 Berm - Non Vegetative Berm 1.43 Rip Rap 0.04 Maritime Forest/Dune 0.07 Berm - Old Field/Early Successional Field 0.35 Berm - Upland Shrubland 0.08 Berm - Non Vegetative Berm 0.33 Rip Rap 0.03 Sand Shell Island 1.59 Maritime Forest/Dune 0.21 Sub Total (Coastal Wetland Impacts Total) 6.78 Forested Wetland Phragmites Emergent Wetland Tidal Emergent (Low Marsh) Berm - Old Field/Early Successional Field 0.19 Berm - Non Vegetative Berm 0.25 Berm - Upland Shrubland 0.26 Mudflat 0.02 Open Water/Channel 0.03 Sand Shell Island <0.01 Tidal Emergent (High Marsh) 2.60 Tidal Emergent (Low Marsh) 0.13 Maritime Forest/Dune 0.04 Berm - Non Vegetative Berm 0.12 Berm - Upland Shrubland 0.18 Maritime Forest/Dune <0.01 Gravel Access Road/Parking <0.01 Open Water/Channel <0.01 Old Field/Early Successional Field 1.80 Berm - Old Field/Early Successional Field <0.01 Maritime Forest/Dune 0.01 Sub Total (Freshwater Wetland Impacts Total) 5.65 Total Wetland Impacts

7 PROJECT PATH: V:\Operations\032\NJDEP\RD Contract 82790\A82790 Projects\Higbee Beach\200 - Deliverables\Drawings\90% Design Drawings\90% CONSTRUCTION 412 MOUNT KEMBLE AVENUE, P.O. Box 1946 MORRISTOWN, NJ MARGARET MCBRIEN FILE NAME: 5_PLANTING PLANS & KEY MAP.dwg PLOT TIME: :04:55.55

8 PROJECT PATH: V:\Operations\032\NJDEP\RD Contract 82790\A82790 Projects\Higbee Beach\200 - Deliverables\Drawings\90% Design Drawings\90% CONSTRUCTION 412 MOUNT KEMBLE AVENUE, P.O. Box 1946 MORRISTOWN, NJ MARGARET MCBRIEN FILE NAME: 5_PLANTING PLANS & KEY MAP.dwg PLOT TIME: :03:59.59

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