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HomeMy WebLinkAbout20020730 Ver 4_More Info Received_202307274700 Falls of Neuse Road, Suite 300 ,,,, Raleigh, North Carolina 27609 moffafi & niahol (919)781-4626 www. rnoffattnichol. corn July 26, 2023 US Army Corps of Engineers Wilmington District 69 Darlington Avenue Wilmington, NC 28403 Attn: Greg Currey / Regulatory Project Manager Subject: Response to Comment Letter #2 for USS Battleship North Carolina - Living with Water Improvements, State ID#: 20-21601-02A/SAW 2010-00175 Dear Mr. Currey, Thank you for your time and effort in reviewing our permit application for the USS Battleship North Carolina Living with Water Improvements Project. Below are the responses to your comments dated July 12, 2023: 1) Alternatives Analysis RESPONSE: Project Purpose and Need The North Carolina Department of Natural and Cultural Resources seeks to mitigate flood risk, preserve access to the USS Battleship North Carolina, a World War 2 Memorial and National Historic Landmark, and restore the local estuarine ecosystem. No Build Alternative The Battleship is berthed on the Cape Fear River approximately 28 miles upstream of the river's confluence with the Atlantic Ocean. Resting on the west bank of the river directly across from downtown Wilmington, it is surrounded by 65-acres of State-owned property on Eagles Island. While much of Wilmington lies on relatively higher ground, Eagles Island mostly is low-lying, brackish, marshland. These marshes are ecologically significant coastal habitats for plant communities, wildlife, anadromous fish, and environmental functions/services including water quality, carbon sequestration, and resiliency hubs. The Battleship also rests approximately 850 meters upstream of the Cape Fear Memorial Bridge. At the foot of the bridge is the NOAA Tidal Gauge (Station 8658120). Established in 1908, the gauge documents the longest tidal record in the region. The tide in this portion of the Cape Fear River fluctuates daily by 4 to 5 feet. The western edge of the Battleship parking lot is below Mean Higher High Water and the highest ground in the parking lot is only a few feet above sea level. Rising seas have increased the frequency and severity of tidal flooding. The Battleship has witnessed a 7,021% increase in tidal flooding since arriving in North Carolina in 1961 with a significant uptick in the 1990s and unprecedented flooding from 2010 to 2020. Tidal data between 2011 - 2020 reveals a 770% increase in tidal flooding over the decade. By 2020, the Battleship property was flooded nearly half of the year. Additionally, the highest tide ever recorded at Station 8658120 occurred during Hurricane Isaias on August 4, 2020. ,A,q Page 1 By law, the Battleship receives no financial support from tax revenues and must rely on visitor receipts (ticket admissions, gift shop sales, programs, events, and rentals) to pay salaries, operations, and regular maintenance. High tides render much of the parking lot unusable and force visitors to wade through water to reach the Visitor Center entrance. Flooding interrupts visitation creating safety and operational hazards and degrades water quality and natural habitats. If flooding continues to impact the number of patrons visiting the site, then the Battleship will be in financial jeopardy. Preferred Alternative The Battleship has been evaluating alternatives to mitigating flooding since 2015 with the initiation of a US Army Corps of Engineers (USACE) Special Investigations study to analyse hydrology and hydraulics on the Battleship site (previously provided as Attachment B). Based on the USACE's analysis and findings, three alternatives were identified and included storm drainage improvements, increase land elevation, and a levee or flood wall system. The preferred alternative from the USACE Study is Alternative 2 — Increase Land Elevation. This alternative is encompassed in the overall design of the "Living with Water" plan, which was modelled after the Dutch approach of integrated water management and flood infrastructure planning with multi -benefit investments. The parking lot will be raised above the more frequent flood elevation using fill material. Raising the elevation of the parking to 6.0 ft NAVD88 will provide additional protection. The design team identified additional project elements that were necessary to reduce the Battleship's risk from nuisance flooding and coastal inundation, as proven by recent data to be increasing. The "Living with Water" project incorporates three major strategies for developing a long-term resiliency plan: coastal defense; "Living with Water" strategy; and connectivity to historical, cultural, and environmental amenities. Finding or creating space for water to provide opportunities for increased water storage, habitat regeneration, and recreation were the guiding principle used throughout project planning and design. The proposed "Living with Water" project provides a sustainable design to address water quality impairments in the lower coastal Cape Fear River watershed. Our team's approach aims to mimic the natural, pre - development hydrology of Eagles Island by reducing runoff and nuisance flooding and help to restore water quality requirements of the receiving surface water. By reducing the existing parking lot area, non -point source discharges will be reduced from vehicles, buses, and operation/maintenance equipment. In addition to creating Primary Nursery Area habitat for forage fish and shrimp, the approximately 8001.f. of restored living shoreline will provide an effective and sustainable method to managing the shoreline within the Battleship's berth. Living Shoreline Alternative The southern shoreline of the Battleship's berth has been heavily modified over the years and is currently covered in loose rubble and concrete roadway slabs and/or barriers to protect against erosion. Design alternatives included a rock sill that would serve as the foundation to regrade the shoreline to create the intertidal regime that will sustain plants and marsh grasses in this environment. The team revisited the use of rock sill, evaluating its performance to maintain the desired shoreline slope and intertidal regime, and ability to minimize wave action and siltation rates that could affect the long-term sustainability of the intertidal habitats. wuee.b EXI Fr GRM I 1MM&U.T-G TTR CL 27Sa 1 I-M 1 M6 HATM I%Jun N. IYr t NOTE` GIGR'.YMU-R 11 LN IBi IWAND MtTG (-)L_Rn NG SNORE UNE TYPICAL SECTION u Lrn M"' • YIY The preferred alternative for the living shoreline includes removing existing rock material and regrading of the bank only to create a natural shoreline with native marsh plantings. ,A,q Page 2 2) Update wetland creation acreage. The boardwalk across the created tidal creek and wetlands cannot be adjusted due to ADA compliance and will be required for full access to the tidal creek. The elevation of the boardwalk was designed to tie-in to sidewalk and cannot be adjusted. The tidal creek and associated wetland habitat shaded by the boardwalk is 0.08 acres and can be removed from the wetland creation total (1.33 acres). The corrected total of wetlands created will be 1.25 acres. Table 1: Sumnary of metland impacts and proposed enhancements Type of Wetland Impact Acreage I S . ft. Description Permanent MP-2 (4b) Fill 0.26 11,326 Fill of existing coastal wetlands MP-2 (1 c) Coastal wetland excavation Excavation 0.74 32,235 (existing wetland to enhanced wetland MP-2(lc) Excavation 0.08 3,485 Existing wetland conversion to constructed tidal creek channel Total 1.08 47,046 Temporary Temporary 0.43 18,731 Temporary coastal wetland impacts in DOT right-of-way Total 0.43 18,731 Creation Tidal wetland 1.15 50,094 Tidal wetland created Tidal creek 0.10 4,356 Tidal creek created Total 1.25 54,450 Note: Bold numbers represent the removal of 0.08 acres of shaded impact from boardwalk to created wetlands. 3) Purpose and Need of the Living Shoreline portion of the Project. The purpose and need of the living shoreline are to naturally stabilize the shoreline along the Battleship berth. A living shoreline was selected as the preferred method of stabilization because it provides wetland habitat and pollutant removal. 4) You state in the application narrative "The wetland and tidal creek will capture, hold, infiltrate, and direct tidal floodwaters to the Cape Fear River." Can you expand on this, describing the flooding reduction mechanisms or processes? Also expand here describing what conditions of the current site facilitate or cause flooding. RESPONSE: The main parking lot will be graded to drain to a central stormwater wetland for detention and treatment of runoff. Discharge from the wetland is directed to a tidal creek that is graded to drain to the ship berth area and the river. During higher flows or river levels, the runoff flow will be spread into the tidal wetland area where some treatment will occur. When the river level lowers, the tidal wetland will be graded to the living shoreline or tidal creek such that the wetland does not hold surface water. ,A„ Page 3 5) Installation of Water Level Sensors The Battleship has committed to a Memorandum of Agreement with the NOAA National Ocean Service in Beaufort to provide for long term physical monitoring of the site post -construction. The installation of water level sensors on site was done between August 2018 and January 2019 to develop an understanding of tidal inundation associated with rainfall and tidal events within the project area. It is anticipated these same sensors (HOBO pressure sensors) can be installed within the requested wetland creation areas to monitor continuous water level data. 6) Provide a Monitoring and Maintenance Plan. An updated monitoring plan is provided as an attachment to this letter. Recommended metrics, success criteria and adaptive management measures have been included. If you have any questions or concerns, please feel free to contact me anytime at dyork@moffattnichol.com. Sincerely, Dawn York 1 Senior Coastal Planner 238 Princess St. Wilmington, NC 28401 P 910.218.7087 M 910.612.1152 moffatt & nichol ��c,ES��TSYsr�i C® A pow za s • yBolo oVati�' h/,q USS BATTLESHIP NORTH CAROLINA LIVING WITH WATER IMPROVEMENTS WILMINGTON, NORTH CAROLINA MONITORING PLAN SCO ID NO. 20-21601-02A July 2023 Prepared For: USS BATTLESHIP NORTH CAROLINA 1 BATTLESHIP ROAD WILMINGTON, NORTH CAROLINA 28401 BATTLESHIP ' MEN .-U.i s CULTURAL RESOURCES NORTH CAROLINA Submitted By: moffatt & nichn 4700 Falls of Neuse Road, Suite 300 Raleigh, North Carolina 27609 919-781-4626 M&N Project No. 10258-02 USS Battleship North Carolina: Living with Water Improvements Monitoring Plan Table of Contents 1. Introduction.............................................................................................................................................................................. iii 1.1. Project Area Wetlands Description............................................................................................................................................iii 1.2. Proposed Wetland Impacts........................................................................................................................................................ ii 2. Monitoring Plan........................................................................................................................................................................ni 3. Success Criteria.......................................................................................................................................................................iv 3.1. Wetland Vegetative Cover......................................................................................................................................................... iv 3.2. Wetland Hydrology (Tidal Events)............................................................................................................................................ iv 3.3. Tidal Creek................................................................................................................................................................................. iv 4. Adaptive Management Plan...................................................................................................................................................iv List of Figures Figure 1: Preliminary jurisdictional determination.................................................................................................................................. ii List of Tables Table 1: Summary of wetland impacts and proposed enhancements..................................................................................................iii Table 2: Post project monitoring for living shoreline and wetland creation and enhancement............................................................iii ,1„ 2 LISS Battleship North Carolina: Living with Water Improvements Monitoring Plan 1. Introduction The Battleship is under threat from storm surge, sea level rise, sunny day tidal flooding and stormwater run-off. Notwithstanding hurricanes, the Battleship has seen more flood stage events in the past decade than in the previous 60 years. Resting 28 miles upstream of the Atlantic Ocean, the Battleship property is hydrologically contiguous to more than 2000 acres of tidal wetlands and intertidal shoreline on Eagles Island. Like many coastal sites, an increasing trend in tidal flooding causes problems. Tidal erosion and flooding inundation damages habitats, creates sink holes, reduces accessibility to the Memorial, and degrades water quality with vehicular pollutants, soil, and silt. The Battleship is committed to an on -the - ground green infrastructure solution to improve accessibility, prepare for, and adapt to climate change, and improve degraded fish and wildlife wetland habitats and water quality. The Living with Water Project is designed to reduce flooding occurrences to ensure the public has safe access to visit the Memorial, as well as support water quality and natural habitat improvements. The Living with Water Project uses nature -based infrastructure to capture, hold, infiltrate, and direct floodwaters to the Cape Fear River. A naturally enhanced shoreline constructed tidal marsh and creek, and parking lot improvements will work in tandem to mitigate flood risk, improve water quality, and provide ecosystem and educational benefits. 1.1. Project Area Wetlands Description The project area encompasses approximately 1.5 acres of brackish and freshwater marshes on the contiguous tidal floodplain of the Cape Fear River (Figure 1). Brackish tidal coastal marsh forms a continuous fringe along the project area shoreline that is interrupted by extensive rip rap within the berth. The landward boundary of the tidal wetlands within the project area is bounded by USS North Carolina Road. The road functions as an artificial berm that has effectively expanded tidal influence into the Battleship's western parking area allowing for disturbed brackish marsh dominated by narrow -leaved cattail (Typha angustifolia) and large dense monospecific stands of common reed (Phragmites australis). A preliminary jurisdiction wetland determination was completed in May 2021 and submitted to the Corps of Engineers and a subsequent site visit was conducted in which wetland line was concurred. USS Battleship North Carolina: Living with Water Improvements Monitoring Plan MOFFATT AND NICHOL PERFORMED A WETLANDISTREAM DETERMINATION ON 25 MAY, 2021. MOFFATT AND NICHOL FINDINGS HAVE NOT BEEN SURVEYED OR VERIFIED BY THE USACE OR NCDWR. THIS EXHIBIT SHOULD BE USED FOR PRELIMINARY Moffatt & nichoi PLANNING PURPOSES MOFFATT AND NICHOL RECOMMENDS CONSULTATION WITH A CIVIL ENGINEER TO CONFIRM THE LOCAL BUFFER REQUIREMENTS- THIS IS NOTA SURVEY NOR SHOULD BE TREATED AS SUCH. Wetland reas (Acres) 1. BATTLESHIP WA: 0.216A VVB. 1.217 NORTH CAROLINA WC: 0.120 Battleship NO -_ - ".WA 1 Battleship Road Wilmington, NC 28401 Aerial Site Map ---' 1 in = 107 R " NEW HANOVER COUNTY ..ilii..:_.. 't .., attic ..._. _.... .. CD I DY Approved By: taste: DY 05111/2021 WN Project No. 10258-01 FIGURE 1 vlv Figure 9: Preliminary jurisdictional determination 1.2. Proposed Wetland Impacts Legend [:]Wetland Study Areas MWetlands 111 Concrete Wall Barrier The Living with Water Project comprises three components, including 1) Living Shoreline, 2) Tidal Creek and Wetland, and 3) Green Infrastructure Improvements. The living shoreline activity will restore more than 720 linear feet of hardened shoreline that had been stabilized over decades with layers of riprap materials to a natural intertidal estuarine shoreline using a nature -based design. Proposed tidal creek and wetland activities will create 1.3 acres of new coastal wetlands, enhance 0.74 acres of existing coastal wetlands through excavation to a lower elevation to capture tidal floodwaters and establish native species, and convert 0.08 acres of existing coastal wetland to open tidal creek channel. The impervious, flood -prone area of existing visitor parking and disturbed wetlands will be converted to intertidal wetland habitat with a tiered elevation design to support habitat migration and allow for adaptation of coastal wetland native plant species. There is a net decrease in impervious area (approximately 0.5 acres) based on removal of the existing deteriorated parking lot. Based on a site visit by Division of Coastal Management staff in June, it was determined that the existing wetlands within the project site are designated as coastal due to tidal influence from receiving waters and presence of coastal wetland species. As listed in Table 2.1 and shown in Figure 2.1 below, a breakdown of wetland impacts are as follows: 111111111110 USS Battleship North Carolina: Living with Water Improvements Monitoring Plan Table 1: Summary of wetland impacts and proposed enhancements T e of Wetland Im act Acreage S . ft. Descri d 1111111100— Permanent MP-2 (4b) Fill 0.26 11,326 Fill of existing coastal wetlands MP-2 (1 c) Coastal wetland excavation Excavation 0.74 32,235 (existing wetland to enhanced wetland MP-2 (1 c) Excavation 0.08 3,485 Existing wetland conversion to constructed tidal creek channel Total 1.08 47,046 Temporary Temporary 0.43 18,731 Temporary coastal wetland impacts in DOT right-of-way Total 0.43 18,731 Creation Tidal wetland 1.15 50,094 Tidal wetland created Tidal creek 0.10 4,356 Tidal creek created Total 1.25 54,450 2. Monitoring Plan Post -project monitoring will be used to determine the success of the project's goals — restoration of an intertidal estuarine shoreline and creation of subtidal and intertidal wetland habitat. The below table shows post -project monitoring procedures, metrics that will be collected and the frequency of data collection. The spatial extent of post -project monitoring is the activity footprint of the restored living shoreline and established tidal wetland. Table 2: Post pr ject monitoring for living shoreline and wetland creation and enhancement Metrics nits Methods Frequency and Timing Percent Cover of Vegetation (0- Percent Cover of Vegetation by Once per year for 3 years post- 100%) species including Phragmites construction Elevation (feet) Various elevation measurements Once per year for 3 years post - throughout Project Footprint construction Wetlands Hydrology Elevation Measurements of water level in Daily Measurements using an feet Low Marsh and in High Marsh accepted water level sensor Tidal Creek and Living Shoreline Visual Monitoring and Once per year for 3 years post - Areas Photographs construction USS Battleship North Carolina: Living with Water Improvements Monitoring Plan In addition to the post -project monitoring procedures in the above table, implementation monitoring will evaluate the extent to which the final mature site mirrors the planned design and includes the following protocols: Preparation of an as -built elevation survey of the entire project area after construction to verify planned target elevations and to provide a baseline against which to measure future changes during the monitoring period. 2. A stratified random design will be used to determine the placement of individual sampling plots along each transect. 3. Plots will be visited and evaluated annually during the period of peak biomass (late July to early August) for species composition and percent cover. 3. Success Criteria 3.1. Wetland Vegetative Cover Year 1: No more than 10% mortality of planted stems and less than 5% cover of Phragmites. Year 2: No more than 10% mortality of planted stems and less than 5% cover of Phragmites. In combination with the planted stems and volunteers of the same species, the low and high marsh areas must exhibit an overall 50 % ground cover. Year 3: No more than 10% mortality of planted stems and less than 5% cover of Phragmites. In combination with the planted stems and volunteers of the same species, the low and high marsh areas must exhibit an overall 85% ground cover. All volunteer species must be noted separately and may be deemed suitable toward meeting the success criteria. 3.2. Wetland Hydrology (Tidal Events) For Low Marsh Areas (S. altem flora): Area must exhibit normal diurnal tide cycle events. For High Marsh Areas: Area must exhibit normal irregular tide events, a minimum of 3 times a year. 3.3. Tidal Creek Tidal Creek must be stable and not show signs of significant erosion, such as headcutting or eroding banks. The monitoring period will be for 3 years, or until deemed successful if corrective measures have to be initiated due to failure of any of the above success criteria. 4. Adaptive Management Plan For the created/enhanced tidal creek wetland areas: If area fails to meet the yearly vegetation success criteria, corrective measures may be implemented. These measures may include supplemental plantings or removal of unsuitable species through herbicidal application or by hand. If the area fails to meet the yearly hydrology performance standard, regrading may be implemented. Other adaptive measures may be deemed necessary contingent on the circumstances.