Environmental Resources Section Public Notice OCT 18 2D12 Alaska District Date Identification No.ER-13-01 U.S. Army Corps of Engineers Please refer to the identification number when replying. The U.S. Army Corps of Engineers (Corps) has prepared an environmental assessment (EA) and finding of no significant impact (FONSI) for the following project: Maintenance Dredging Nome Harbor Entrance Channel Nome, Alaska The Corps proposes to conduct annual maintenance dredging of sediment from the existing Nome Harbor entrance channel and basin each year for 10 years, 2013 through 2022. The Federal project at Nome Harbor includes 3,950 linear feet of channel that would be dredged to authorized project depths ranging from -22 feet below mean lower low water (MLLW ) to -10 MLLW. Littoral transport and storms deposit large quantities of marine sediment within the channel, and the Federal project must be dredged annually to maintain safe access to the harbor. An estimated 50,000 cubic yards of sediment would be dredged in 2013, with about 34,000 cubic yards dredged most subsequent years through 2022. The proposed project, alternatives, and potential environmental impacts are described in the enclosed EA, which is available for public review and comment until November 19,2012. It may be viewed on the Alaska District's website at: www.poa.usace.army.mil.Click on the Reports and Studies button, look under Documents Available for Public Review, and then click on the Civil Works link. To obtain a printed copy, email: [email protected] or send a request to the address below: U.S. Army Corps of Engineers, Alaska District ATTN: CEPOA-EN-G-ER P.O. Box 6898 Joint Base Elmendorf-Richardson, Alaska 99506-0898 Comments on the EA and proposed project may be sent to the email or postal address. Michael R. Salyer Chief, Environmental Resources Section Environmental Assessment and ® Finding of No Significant Impact US Army Corps of Engineers Alaska District Maintenance Dredging Nome Harbor Entrance Channel Nome, Alaska October 2012 FINDING OF NO SIGNIFICANT IMPACT Maintenance Dredging Nome Harbor Entrance Channel Nome, Alaska The U.S. Army Corps of Engineers (Corps) will conduct annual maintenance dredging of sediment from the existing Nome Harbor entrance channel and basin each year for 10 years, 2013 through 2022. The Federal project at Nome Harbor includes 3,950 linear feet of channel that would be dredged to authorized project depths ranging from -22 feet below mean lower low water (MLLW) to -10 MLLW. Littoral transport and storms deposit large quantities of marine sediment within the channel, and the Federal project must be dredged annually to maintain safe access to the harbor. An estimated 50,000 cubic yards of sediment would be dredged in 2013, with about 34,000 cubic yards dredged most subsequent years through 2022. Since 2009, the Corps has successfully placed dredged material from the channel on the shoreline east of the breakwater for beach nourishment. This helps replace sediment partially blocked from the area by the causeway and breakwater and substantially increases the width of protective beach along the foot of the rock seawall that extends east along the Nome waterfront. The sediment has been typically transported from a hydraulic cutter-head dredge through a pipeline to the placement site. The Corps plans to continue using this dredged material placement strategy during the period 2013 through 2022. This action has been evaluated for its effects on several significant resources, including fish and wildlife, wetlands, threatened or endangered species, marine resources, and cultural resources. No significant short-term or long-term adverse effects were identified. This Federal action complies with the National Historic Preservation Act, the Endangered Species Act, the Clean Water Act, the Magnuson-Stevens Fishery Conservation and Management Act, and the National Environmental Policy Act. The completed environmental assessment supports the conclusion that the action does not constitute a major Federal action significantly affecting the quality of the human and natural environment. An environmental impact statement (EIS) is therefore not necessary for the maintenance dredging. ________________________________ ____________________ Christopher D. Lestochi DATE Colonel, Corps of Engineers District Commander Table of Contents 1.0 Introduction .......................................................................................................................... 1 1.1 Purpose and Need ............................................................................................................ 1 1.2 Project Authority .............................................................................................................. 2 1.3 Project Description ........................................................................................................... 2 2.0 Alternatives and Proposed Action ....................................................................................... 2 2.1 No Action Alternative ...................................................................................................... 2 2.2 Action Alternatives ........................................................................................................... 2 2.3 Preferred Alternative ........................................................................................................ 5 2.4 Mitigation Measures ......................................................................................................... 5 3.0 Affected Environment ......................................................................................................... 6 3.1 Project Site Description .................................................................................................... 6 3.2 Marine Environment ........................................................................................................ 7 3.3 Biological Resources ..................................................................................................... 10 3.4 Threatened and Endangered Species .............................................................................. 11 3.5 Essential Fish Habitat ..................................................................................................... 12 3.6 Cultural and Historic Resources ..................................................................................... 12 3.7 Economics and Subsistence ........................................................................................... 13 3.8 Air and Noise Quality .................................................................................................... 13 4.0 Environmental Consequences ........................................................................................... 14 4.1 Effects on the Marine Environment ............................................................................... 14 4.2 Effects on Biological Resources .................................................................................... 15 4.3 Effects on Threatened and Endangered Species ............................................................ 17 4.4 Effects on Essential Fish Habitat ................................................................................... 17 4.5 Effects on Cultural and Historic Resources .................................................................. 17 4.6 Effects on Economics and Subsistence .......................................................................... 18 4.7 Effects on Air and Noise Quality ................................................................................... 18 4.8 Effects on Environmental Justice and Protection of Children ....................................... 18 4.9 Cumulative Effects ......................................................................................................... 19 5.0 Public Involvement, Regulatory Compliance, and Agency Coordination ......................... 21 5.1 Compliance with Laws and Regulations ........................................................................ 21 5.2 Mitigation ...................................................................................................................... 23 6.0 Conclusion ......................................................................................................................... 23 7.0 Document Preparation ....................................................................................................... 23 8.0 References .......................................................................................................................... 24 List of Figures Figure 1. Location and vicinity of Nome Harbor dredging project features. ................................. 1 Figure 2. Drawing of proposed limits of dredging, and the dredged material placement area ...... 3 Figure 3. Aerial oblique view of current harbor configuration. ..................................................... 7 Appendices Appendix 1: 404(b)(1) Evaluation Appendix 2: EFH Evaluation ABBREVIATIONS AND ACRONYMS ADEC – Alaska Department of Environmental Conservation ADFG – Alaska Department of Fish and Game AHRS – Alaska Heritage Resources Survey APE – Area of Potential Effect BMP’s – Best Management Practices Corps – U.S. Army Corps of Engineers CWA – Clean Water Act cy – Cubic Yards EA – Environmental Assessment EFH – Essential Fish Habitat EPA – U.S. Environmental Protection Agency ESA – Endangered Species Act FONSI – Finding of No Significant Impact HAPC – Habitat Area of Particular Concern MHHW – Mean Higher High Water MLLW – Mean Lower Low Water NMFS – National Marine Fisheries Service NOAA – National Oceanic Atmospheric Administration SHPO – State Historic Preservation Officer USFWS – U. S. Fish and Wildlife Service USACE – U.S. Army Corps of Engineers Environmental Assessment Maintenance Dredging Nome Harbor Entrance Channel Nome, Alaska 1.0 Introduction 1.1. Purpose and Need The proposed action is to conduct annual maintenance dredging within the Federal project limits at Nome Harbor to include the entrance channel, the inner north harbor, and the sediment traps as needed (figure 1). Coastal transport mechanisms and storms deposit large quantities of marine sediment within the channel, and the Federal project must be dredged annually to maintain the authorized project depths and preserve safe navigational access. Without the proposed action, shoaling will rapidly restrict access to Nome Harbor by ships and barges. Figure 1. Location and vicinity of Nome Harbor dredging project features. 1 1.2 Project Authority The original improvements to Nome Harbor were approved via the Rivers and Harbors Act of 8 August 1917, Public Law (P.L.) 37. Subsequent authorizations modified the original authorization to produce the current project configuration completed in 2006: • Rivers and Harbors Act, 30 August 1935 • Rivers and Harbors Act, 16 June 1948 (P.L. 80-649) • Section 101 (a)(3), P.L. 106-53, Water Resources Development Act of 1999 1.3 Project Description The Federal project at Nome Harbor consists of an approximately 3,950-foot-long entrance channel, an inner harbor basin, and a sediment trap (figure 2). These are dredged to project depths ranging from -22 to -10 feet mean lower low water (MLLW). Between 2006 (when the current entrance channel configuration was completed) and 2011, the quantity of sediment dredged annually has ranged from 20,000 to 49,595 cubic yards. The inner sediment trap requires dredging roughly once every 5 years. The dredging planned for 2013 would include the sediment trap and is expected to remove about 50,000 cubic yards. In subsequent years, dredging of just the entrance channel and inner basin would remove about 34,000 cubic yards. 2.0 Alternatives and Proposed Action 2.1 No Action Alternative The No Action alternative would result in no annual maintenance dredging of the Nome Harbor entrance channel. This alternative would avoid the potential environmental impacts and port access issues described in later sections. However, it would also allow the continued accumulation of sediments that would rapidly restrict safe access by ships and barges to the harbor at Nome. 2.2 Action Alternatives Any dredging action requires a dredging method, a place to put the dredged material, and the means of transporting the dredged material to the disposal/placement site. The Corps’ review of dredging alternative for this project has been informed by its many decades of dredging activities conducted at Nome. The basic choices of dredge type are mechanical (clamshell) versus hydraulic (suction), and transport via a barge or hopper versus a pipeline. 2 Figure 2. Drawing of proposed limits of dredging, and the dredged material placement area (excerpted from USACE 2012). Clamshell Dredge. Clamshell dredging for the proposed project requires the use of a barge- mounted crane with a clamshell bucket that would be used to remove sediment from the harbor bottom. An open bucket clamshell dredge is often used in marine environments due to an increased rate of efficiency for moving sediment. The captured sediment is primarily what is lifted to the surface, and there is little entrained water that is moved to the dredged material placement site. Furthermore, in comparison with the other dredging methods, less turbidity can be expected, thus minimizing the spread of containments to adjacent areas or to the water column. 3 Hopper Dredge. A hopper dredge operates by use of suction “drag heads” that extend from the hull of the dredge down into the substrate to be dredged. Through suction, materials are brought up into the open hull of the dredge until the hopper is full and the material can then be moved to a dredged material placement site. Use of a hopper dredge works best in sandy environments. The suction of material also brings in huge volumes of water. The excess water (return water) is allowed to overflow the hopper and flow back into the waterbody. The overflow water can increase turbidity and may not meet water quality standards immediately after discharge (dewatering). Pipeline Dredge. A pipeline dredge, like the hopper dredge, uses suction and a cutter head to bring sediment from the bottom of the harbor. However, a pipeline dredge does not have a hopper to contain the material. Instead, the material is moved directly to the placement site. As with a hopper dredge, excess water is removed with the sediment. The excess water helps to keep the sediment “fluid” so that it can be pumped to the dredged material disposal facility. The pipeline dredge must have a placement location within pumping range of the dredge. Both clamshell and hydraulic pipeline dredges have been used at Nome in the past. The pipeline dredge has some distinct advantages for the maintenance dredging project at Nome. Pipeline dredges are able to operate almost continuously (without pauses to change out scows or hoppers), resulting in higher productivity and faster project completion. At Nome, a pipeline discharge system allows the dredge and support craft to work almost entirely within the protection of the breakwater and causeway; if the dredged material had to be transported out of the harbor in a scow, high winds or unfavorable sea conditions could slow or temporarily halt the dredging operations. Dredged Material Placement. At the present time, the maintenance project has only one viable placement site for the dredged material. The onshore placement area is at the shoreline at the western end of the rock seawall (figures 1 and 2). This roughly 600-foot by 300-foot (less than 5 acres) area would primarily receive sediment dredged from the harbor basin and inner channel. This placement site has been used successfully since 2009, and its use has contributed to the widening of the beach in front of the Nome seawall. The dredged material would be placed at the waterline within this area and periodically spread with a grader or bulldozer to match the surrounding beach profile. The dredged material discharged in this area would serve as beach nourishment as it is naturally redistributed eastward along the foot of the seawall. The coordinates of the corners of the onshore placement area are: • 64° 29 52.76’ N, 165° 25 00.00’ W; • 64° 29 51.46’ N, 165° 24 47.15’ W; • 64° 29 48.73’ N, 165° 24 50.13’ W; • 64° 29 50.03’ N; 165° 25 03.00’ W. 4