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Home My WebLink About2026-02-11 USACE WH 403 PresentationLETTER REPORT & ENVIRONMENTAL IMPACT STATEMENT Presented by: SAW Team U.S. Army Corps of Engineers Wilmington District February 11th, 2026 NEW HANOVER PORT, WATERWAY & BEACH COMMISSION WATER RESOURCES DEVELOPMENT ACT OF 2020 (WRDA) SECTION 403 INTRODUCTION FEB 2020 - North Carolina State Ports Authority (NCSPA) Section 203 Feasibility Study ✓Tentatively Selected Plan recommended deepening to 47 feet ✓Submitted to the ASA(CW) in February 2020 for Review DEC 2020 – Water Resources Development Act (WRDA 2020) ✓Congress authorized the navigation project, at a total cost of $834,093,000 through Section 403 of Water Resources Development Act (WRDA) 2020. WRDA 2020 included a requirement that a final assessment address the concerns, recommendations, and conditions identified by the ASA (CW). MAY 2020 – Assistant Secretary of the Army (Civil Works) ASA (CW) Review Assessment ✓Transmitted to Congress with unresolved comments including: - Reframe assumptions and screening of alternatives - Perform economic analysis using USACE methodology at multiple depths - Conduct National Environmental Policy Act (NEPA) analysis including supporting engineering modeling and appropriate sea level rise - Finalize a mitigation plan and a real estate plan - Conduct Independent External Peer Review (IEPR) OCT 2023 – Section 403 Letter Report and Environmental Impact Statement ❑The Wilmington District was tasked with producing a Letter Report and Environmental Impact Statement to address issues from the Review Assessment through a cost-share agreement with the NCSPAN PURPOSE AND NEED: •Describes the what and why for the proposed action •Informs the development of alternatives WILMINGTON HARBOR 403 PURPOSE AND NEED •PURPOSE. Contribute to national economic development (NED) by addressing transportation inefficiencies for the forecasted vessel fleet, consistent with protecting the Nation’s environment. •NEED. A ddress the constraints that contribute to inefficiencies in the existing navigation system’s ability to safely serve forecasted vessel fleet and cargo types and volumes. NEPA PROCESS June 7-July 22, 2024Notice of Intent (Summer 2024) Public Review and Comment Period (Fall 2025) Issue Final EIS (Summer 2026) DESCRIPTION OF ALTERNATIVES •Depth increased from -42’ to -47’ MLLW with 2’ stepdown at Battery Island •Side Slopes. •3:1 (horizontal to vertical) from Anchorage Basin to Lower Swash •5:1 from Battery Island to Baldhead Reach 4 •2’ allowable overdepth authorized •Where hard-rock present, 1’ additional over- depth •9.1 mi channel extension from BH Reach 3 •Widen areas identified in the 203 Report (Table 1) •Depth -42’ MLLW •Side Slopes: 3:1 (horizontal to vertical) •Depth increased from -42’ to -46’ MLLW with 2’ stepdown at Battery Island •Side Slopes. •3:1 (horizontal to vertical) from Anchorage Basin to Lower Swash •5:1 from Battery Island to Baldhead Reach 4 •2’ allowable overdepth authorized •Where hard-rock present, 1’ additional over- depth •9.1 mi channel extension from BH Reach 3 •Widen areas identified in the 203 Report (Table 1) The action alternatives will be compared to the No Action alternative to form the basis for engineering, environmentalBACKGROUND. and economic analysis, and decision-making for the Wilmington Harbor Section 403 effort. DESCRIPTION OF ALTERNATIVES REACH WIDTH DEPTH - MEAN LOWER LOW WATER (MLLW) Exist. Channel Width Proposed Channel Width Future Without Project 46 FT ALT 47 FT ALT (ft)(ft)(ft)(ft)(ft) AN C H O R A G E BA S I N Anchorage Basin - 0+00 to 8+00 448-548 625 - 1509 38 46 47 Anchorage Basin - 8+00 to 84+85 547-1200 625 - 1509 42 Between Channel 500-545 625 Fourth East Jetty 455-550 550 Upper Brunswick 400-775 500 Lower Brunswick 400-775 500 MI D RI V E R Upper Big Island 540-700 660 42 46 47 Lower Big Island 507-695 500 Keg Island 400-695 500 Upper Lilliput 400-610 500 Lower Lilliput 600 600 Upper Midnight 600 600 Lower Midnight 600 600 Reaves Point 400-600 500 Horseshoe Shoal 400-607 500 Snows Marsh 400-607 500 Lower Swash 400-820 800 - 500 OC E A N B A R IN N E R Battery Island 500-820 800 - 1300 44 48 49 Southport 500 800 OU T E R Baldhead - Caswell 500-646 800 Smith Island Channel 650-895 900 Baldhead Shoal - Reach 1 775-900 750 Baldhead Shoal - Reach 2 900 900 Baldhead Shoal - Reach 3 500 600 - 900 Offshore Extension (New Reach 4)NA 600 Conditionally AuthorizedPreliminary 2nd Action Alt. Standardizing the width of the channel ODMDS PRELIMINARY ALTERNATIVES ARRAY Wideners proposed TABLE 1. -52 -51 -50 -49 -48 -47 -46 -45 -44 -43 -42 -41 -40 -39 -38 -37 -36 -35 -34 -33 -32 -31 -30 -29 -28 -27 -400 -375 -350 -325 -300 -275 -250 -225 -200 -175 -150 -125 -100 -75 -50 -25 0 25 50 75 100 125 150 175 200 225 250 275 300 325 350 375 400 El e v a t i o n , M L L W f e e t Distance (ft) Authorized - NAA Allowable Overdepth - NAA 47-FT ALT Allowable Overdepth Bathymetry (example) 47FT Alternative - Allowable 2' Overdepth for Payment During Construction and Maintenance (-49' MLLW) 47FT Alternative - Depth (-47' MLLW) Allowable 2' Overdepth for Payment during Maintenance (-44 MLLW) NON-ROCK CROSS-SECTION (FWOP & 47’ ALT) WILMINGTON HARBOR 403 LETTER REPORT & ENVIRONMENTAL IMPACT STATEMENT FWOP NOTE: The vertical and horizontal scales are not the same FWOP LEGEND TYPICAL 3:1 SIDE SLOPE TYPICAL 5:1 SIDE SLOPE -52 -51 -50 -49 -48 -47 -46 -45 -44 -43 -42 -41 -40 -39 -38 -37 -36 -35 -34 -33 -32 -31 -30 -29 -28 -27 -400 -375 -350 -325 -300 -275 -250 -225 -200 -175 -150 -125 -100 -75 -50 -25 0 25 50 75 100 125 150 175 200 225 250 275 300 325 350 375 400 El e v a t i o n , M L L W f e e t Distance (ft) Authorized - NAA Allowable Overdepth - NAA 47-FT ALT Initial Deepening Required Rock Overdepth Initial Deepening Allowable Rock Overdepth Allowable Overdepth Bathymetry (example) Allowable 2' Overdepth for Payment during Maintenance (-44 MLLW) Authorized Depth / Federal Project Depth (-42' MLLW) 47FT Alternative - Allowable 2' Overdepth for Payment During Maintenance (-49' MLLW) 47FT Alternative - Depth (-47' MLLW) 47FT Alternative - Initial Required 1' Rock Clearing Overdepth (-48' MLLW) 47FT Alternative - Allowable 2' Overdepth for Payment During Initial Rock Clearing (-50' MLLW) ROCK CROSS-SECTION (FWOP & 47’ ALT) WILMINGTON HARBOR 403 LETTER REPORT & ENVIRONMENTAL IMPACT STATEMENT (Maintenance) FWOP FWOP LEGEND BENEFICIAL USE SITES INITIAL PLACEMENT AND O&M ➢15 intertidal mudflat creation/renourishment o Around marshes and bird islands ➢2 beaches in New Hanover County o Masonboro &Carolina Beach ➢3 beaches in Brunswick County o Oak Island, Caswell, Bald Head ➢2 bird islands o Ferry Slip & South Pelican ➢1 offshore fisheries structure made of rock Brackish Habitats/Marsh High Saline Habitats/Marsh MITIGATION – WETLAND PRESERVATION WILMINGTON HARBOR 403 Eagle Island. Restoration and enhancement of approximately 120 acres of phragmites australis and brackish marsh wetlands Wetland Preservation. Preservation of approximately 550 acres of high-quality forested freshwater wetlands LD2 EXISTING CONDITIONFISH HABITAT MITIGATION WILMINGTON HARBOR 403 Aquatic Habitat. To compensate for the loss of aquatic habitat, fish passage improvement projects would be constructed at Lock and Dams 1 and 2 on the Cape Fear River to enable anadromous fish to access quality habitat upstream of those facilities. ECONOMIC ASSUMPTIONS WILMINGTON HARBOR 403 LETTER REPORT & ENVIRONMENTAL IMPACT STATEMENT •The action alternatives would not increase the volume of cargo differently than the without project scenario; the same amount of cargo will be moved more efficiently (NED Benefits). •Wilmington Harbor Design Vessel: Post-Panamax Generation III ‒1,200 to 1,220 feet length over all (LOA) ‒44 1,200-foot LOA calls in 2021 ‒168 feet beam (Max. for expanded Panama Canal locks) •Ability to move the same amount of cargo using larger ships = fewer trips – fewer vessel trips = lower transportation costs (benefits) •Due to the current channel’s configuration, light loading practices continue as the least-cost alternative to intermodal shifts in cargo –Overall vessel fleet composition will remain much the same as it is today –Bulker and Chemical Tanker fleet mix will not incorporate new, larger classes, but shift towards larger end of existing fleet, and remain draft constrained –Asian container shippers will not fully utilize the available fleet of Post-Panamax Generation III vessels and retain smaller vessels –A smaller share of the South/Central American container cargo is shifted to the light-loaded, Post-Panamax Generation I fleet, resulting in smaller vessels continuing to call on Wilmington ‒51 feet draft ‒Nominal 20’ Equivalent (TEU) intake of ~ 10,000 to 15,000 TEUs 23% potential cost decrease compared with a 12,500 TEU container ship COST PER TEU PER DAY AT SEA 12,500 TEU 18,000 TEU 22,000 TEU 24,000 TEUSource: Van Marle (2013) AA2 (-46’)AA1 (-47’) Project First Cost (FY25 Price Levels)$ 968,199,000 $ 1,140,270,000 IDC $ 76,318,000 $ 89,882,000 Economic Cost $ 1,044,518,000 $ 1,230,152,000 Annual O&M $ 12,965,000 $ 14,420,000 Average Annual Equivalent (AAEQ) Costs $ 41,524,000 $ 48,970,000 •Annualized using FY25 Current Discount Rate of 3.0% SE C T I O N 4 0 3 PROJECT COST COMPARISON. AVERAGE ANNUAL COSTS •Compensatory mitigation costs are included in this cost •The environmental impacts of the action alternatives are similar nature and magnitude relative to benefits AA2 (-46’)AA1 (-47’) AAEQ Benefits (slide 6)$71,189,000 $83,278,000 AAEQ Costs (slide 9)$53,561,000 $62,230,000 Net Benefits $17,628,000 $21,048,000 Net Benefit diff (%) 19% BCR @ 3.0% 1.3 1.3 SE C T I O N 4 0 3 (Conditionally Authorized) •>1.0 Benefit to Cost Ratio = Federal Interest •The NED Plan must reasonably maximize Net Economic Benefits •AA1’s (-47) Net Benefits are 19% greater than AA2’s (-46’) •AA2 & AA1 have 1.3 Benefit to Cost Ratio •Conditionally authorized plan (AA1) (-47’) is the Recommended Plan and National Economic Development Plan. NATIONAL ECONOMIC DEVELOPMENT PLAN SELECTION. Action Alternative RESULTS. VISUALIZATION. Figure (right) shows project impacts in red and sea level impacts in yellow under existing (SLC0) conditions for each action alternative. Acres converted with AA1 under existing sea level conditions~1071 Acres converted with AA2 under existing sea level conditions~ 971 Action alternatives would result in up to 1,071 acres of freshwater forested wetlands being converted to brackish wetlands Total area of each salinity zoneWETLANDS IMPACTS AQUATIC HABITAT SUITABILITY IMPACTS WILMINGTON HARBOR 403 LETTER REPORT & ENVIRONMENTAL IMPACT STATEMENT •Indicator species selected: ‒Atlantic sturgeon ‒Blueback herring ‒Striped Bass ‒Southern flounder ‒Previous studies: redfish, white shrimp •Example Model Inputs: ‒Temperature, dissolved oxygen, salinity, depth •Different species models analyze different portions of the water column •Conditions with and without the project can be compared to assess changes in habitat quality due to the project •Results are expressed in habitat units (HUs) ‒Eastern oyster ‒American shad ‒Spot HABITAT SUITABILITY INDEX (HSI) MODELS were applied to identify potential indirect impacts to fish and fish habitat associated with each alternative. An example map of results is shown below. GROUNDWATER MODEL RESULTS WILMINGTON HARBOR 403 LETTER REPORT & ENVIRONMENTAL IMPACT STATEMENT MODELING CONCLUSIONS. •Deepening the channel will not introduce new flows of salinity from the Cape Fear River into the aquifers used for drinking water specifically within the Carolina, Baldhead, and Kure Beach communities. •Significant danger of saltwater intrusion without the deepening project, especially in coastal areas (i.e. Carolina and Kure Beach) where heavy groundwater pumping is already occurring. •Sea level rise and, especially, pumping, are far more impactful to saltwater intrusion than the deepening project. •An analysis of gradient changes due to the deepening at known groundwater contamination sites showed no major impacts to the movement of groundwater contaminant plumes near the Cape Fear River. Grid Cross-Section, Showing Hydrogeologic Layering 17 N PIANC FORMULA 0 200 400 •Clear decrease in overall bottom stress when going from FWOP to either alternative •A lower number of vessel passages, not bathymetry, create the greatest decrease in bottom stress/erosion potential •Alternative 1 (-47’) does a slightly better job than Alternative 2 (-46’) at decreasing bottom stress RESULTS. REACH % DELTA IN BOTTOM STRESS (FWOP -ALT 1 (47’) @ MLLW SP X 1 Pa n a m a x PP X G e n I PP X G e n I I PP X G e n I I I GP T a n k e r MR T a n k e r LR T a n k e r Ve r y S m a l l Bu l k e r Sm a l l Bu l k e r Me d i u m Bu l k e r La r g e Bu l k e r Ve r y L a r g e Bu l k e r AN C H O R A G E BA S I N Anchorage Basin Between Channel Fourth East Jetty Upper Brunswick Lower Brunswick MI D RI V E R Upper Big Island Lower Big Island Keg Island Upper LIlliput Lower Lilliput Upper Midnight Lower Midnight Reaves Point Horseshoe Shoal Snows Marsh Lower Swash OC E A N B A R IN N E R Battery Island Southport OU T E R Baldhead - Caswell Smith Island Channel Baldhead Shoal - Reach 1 VESSEL FLEET FORECAST FWOP - ALT 1 (47') ECONOMIC ANALYSIS: FORECASTED VESSEL TRIPS (2036, 2056, 2085) 8 Vessel types with negligible changes in bottom stresses 2 Vessel types with small decreases in bottom stresses 3 Vessel types with moderate decreases in bottom stresses FWOP (42’) 2036 FWOP (42’) 2056 FWOP (42’) 2085 AA1 (47’) 2036 AA1 (47’) 2056 AA1 (47’) 2085 •AA2 (46’) 2036 •AA2 (46’) 2056 •AA2 (46’) 2085 1 -0.625 -2.25 -3.875 -5.5 -7.125 -8.75 -10.375 -12 VESSEL WAKE FOR THE FORECASTED FLEET Gates and Herbich SEDIMENT QUALITY TESTING WHEN WILL SEDIMENT BE TESTED? •Before dredging, during the Pre-Construction Engineering and Design (PED) phase WHAT TYPE OF TESTS WILL TAKE PLACE? Engineering. To determine the visual classification (USCS symbol) and grain sizes of unconsolidated sediments we will perform the following three tests: •ASTM D6913, Particle-Size Distribution of Soils Using Sieve Analysis •ASTM D2487, Standard Practice for Classification of Soils for Engineering Purposes •Visual, volumetric percentage of shell and rock fragment determination. •Additional tests as needed for consolidated sediments Environmental. Testing requirements for compliance with Clean Water Act and other environmental laws will be coordinated with state and federal agencies, such as the North Carolina Department of Environmental Quality and U.S.Environmental Protection Agency. DESCRIPTION OF ALTERNATIVES QUESTIONS? For more project information please visit: https://wilmington-harbor-usace-saw.hub.arcgis.com/