Posted on October 9, 2024
PUBLIC NOTICE
OF PROPOSED DISCHARGES OF DREDGED AND FILL MATERIAL FOR THE LOWER COLUMBIA RIVER CHANNEL MAINTENANCE PLAN, DREDGED MATERIAL MANAGEMENT PLAN
Oregon and Washington State
Issue Date: 10/7/2024
Expiration Date: 11/6/2024
Interested parties are hereby notified that the U.S. Army Corps of Engineers, Portland District (Corps) proposes to discharge dredged and fill material during implementation of a Dredged Material Management Plan and integrated Environmental Impact Statement (DMMP-EIS) for the purpose of maintaining the congressionally authorized channel dimensions of the Lower Columbia River (LCR) Federal Navigation Channel (FNC), part of the Columbia and Lower Willamette Rivers (C&LW) Project. This public notice is required by the provisions of section 103 of the Ocean Dumping Act (ODA) (aka, Marine Protection, Research, and Sanctuaries Act (MPRSA)) and section 404 of the Clean Water Act (CWA).
LCR FNC maintenance dredging would occur annually utilizing a variety of dredge equipment. The intent of maintenance dredging is to reduce impediments to navigation by dredging to authorized dimensions, plus advanced maintenance dredging (AMD). The overall purpose of the DMMP-EIS is to define the dredged material management practices for the LCR FNC to maintain the authorized dimensions for a minimum of 20 years using the dredged material disposal alternative that represents the least-cost consistent with sound engineering practices and meeting the environmental standards established by the CWA 404(b)(1) evaluation process and ocean dumping criteria. Dredged material is placed in a manner that retains sediment within the Columbia River system to the greatest extent practicable without increasing future dredging requirements. The Corps proposes to transport and place dredged material in deep water, in-water shallow sites, confined aquatic facilities (confined aquatic placement with structures), upland placement sites, beach nourishment (shoreline placement) sites, including the use of temporary in-water transfer sites when needed, and the ocean deep-water site (DWS) ocean dredged material disposal site (ODMDS).
Congress has authorized the Corps to construct and improve Federal navigation projects over time to provide safe, reliable, efficient, and environmentally sustainable waterborne transportation systems for the movement of commerce, national security needs, and recreation. The Congressional authorizations relevant to the LCR FNC have not changed since this channel was last deepened.
Project Description
The forecasted average volume of material needed to be dredged to maintain the authorized dimensions for the next 20 years is expected to be 9.2 million cubic yards annually. The channel is typically maintained using hydraulic (hopper and pipeline) dredges but mechanical dredges with material placement barges can also be used. This volume includes the rehandling of material placed temporarily in locations referred to as in-water transfer sites. Material is brought to a transfer site by a hopper dredge and a pipeline dredge would then pump the material to an upland, shoreline, in-water shallow, or confined aquatic placement site. These forecasted numbers include AMD to maintain the authorized channel dimensions between maintenance dredging events.
Over the next 20 years, approximately 184 million cubic yards of material dredged from the FNC would be placed within in-water deep placement areas, in-water shallow sites, shoreline sites, upland sites, confined aquatic facilities (confined aquatic placement with structures), and DWS ODMDS, including temporary placement in in-water transfer sites. Approximately 178 thousand cubic yards of clean rock fill material would also be placed in water to construct dredged material retention structures and repair existing pile dikes to retain dredged material.
Composition of material to be dredged and subsequently discharged is predominantly clean sand. Historic sediment sampling and analysis have shown that material removed during LCR FNC maintenance dredging has been determined to be suitable for unconfined aquatic in-water placement. Based on this analysis, it is unlikely that dredging the materials in the FNC would release contaminants. Testing in May 2016 found the sediments to be dominated by sand (greater than 97% sand and gravel and less than 2.6% silt and clay) and low total organic carbon content (<0.3%) (Corps 2017). In accordance with the Northwest Regional Sediment Evaluation Team (RSET) SEF guidance (RSET 2018), chemical analysis was not required, because sand particles are inert and do not bind contaminants. The Corps will continue to sample the channel’s sediments per the 2018 SEF to monitor for sediment characteristics, including contaminants. Sediments that are tested and deemed to be unsuitable (that is, not suitable for unconfined aquatic in-water placement) would not be placed in water but would instead be placed in upland sites.
In-water deep placement will continue to occur in depths greater than 20 feet in the area contiguous with the FNC throughout the mainstem Columbia River from RM 3 to RM 105.5. Placement areas vary depending on dredge areas and survey depths each year. Placement occurs strategically in areas where material is typically dispersed out of the site over time, which provides in-water deep sites with renewable capacity. As the hopper dredge is moving, the hopper doors open, and the material is discharged at varying rates depending upon how far the hopper doors are opened. During pipeline dredge placement of material at in-water sites, material is continuously discharged during dredging operations using a down-pipe with a diffuser plate at the end.
In-water shallow placement sites are defined as sites that initially contain areas that are shallower than -20 feet Columbia River Datum (CRD) and will remain at elevations below ordinary high water during and after dredged material placement. Portions of shallow-water sites may be submerged or tidally or seasonally inundated. Smaller volume sites may be filled in a single event. Larger volume sites would be filled incrementally over multiple, similar placement events with each event raising a portion of the site to its estimated design fill elevation. Events may occur within the same dredge season or years apart. Dredged material placement in shallow water uses an enclosed floating pipe to discharge the dredged material at low pressure at the water surface. A diffuser plate may be attached to the open end of the discharge pipe to increase material dispersal.
Confined aquatic placement sites are defined as sites where new structures are added to retain dredged material within the site, at locations where material would otherwise be transported by natural riverine processes resulting in adverse effects such as increased shoaling in the LCR FNC. The structures would be installed first and then dredged material would be placed between the structures where it is protected from erosion. Structures would be constructed from timber or steel piles with enrockment, or enrockment only depending on location and river flow velocities. Portions of structures could be completely or periodically inundated with water or designed with crest elevations above high water depending on the local hydraulic conditions. New pile structures would be constructed using barge-mounted cranes that drive timber or steel piles into the river bottom using vibratory or impact hammers. Rock placement would occur using land-based or barge-based excavators and cranes, or specialized placement barges. Sites would be filled incrementally over multiple, similar placement events with each event raising a portion of the site to its estimated design fill elevation. Events may occur within the same dredge season or years apart.
Upland placement may occur on islands in the river or locations on the mainland accessible from the river. Upland sites are defined as sites that initially contain areas of land above ordinary high water. Areas below ordinary high water must first be filled using the shoreline method to create land. The upland placement method is used to place dredged material on top of existing land and fill up to the final site elevation. Sites are filled in layers over multiple, similar placement events with each event raising the fill elevation of the site. Events may occur within the same dredge season or years apart. Containment berms are typically created around the perimeter of the upland placement area. Discharge of water from the final settling pond back into the river is controlled by the use of weirs. The return water discharge pipe is typically submerged in the river 20 feet or deeper.
The crest elevations of shoreline placement sites are at or above the ordinary high water mark (OHWM)(or mean higher high water mark in tidally influenced areas) after placement. Shoreline sites are typically shaped as long, narrow fills. Smaller volume sites may be filled in a single event. Larger volume sites would be filled incrementally over multiple, similar placement events with each event creating new land over a portion of the site. Broader shoreline sites may then be subsequently filled to a higher elevation using the upland placement method. Events may occur within the same dredge season or years apart. During shoreline placement, dredged material is pumped through a floating discharge pipe. As the sand exits the shore pipe, the sand settles out on the shoreline while the water returns to the river. After sufficient sand has settled out and begins to increase in height, it is moved by bulldozers to match the elevation of the existing shoreline at approximately the high-water line. During placement, a temporary sand berm is constructed to retain sand.
A transfer site is an in water holding area created for temporary storage of dredged material. The transfer operation is used only when it is more efficient and less expensive than other methods available to move dredged material directly from a shoal to a permanent placement site. Transfer sites are typically operated between depths of 30 to 43 feet, although some shallower locations may require shallower operating depths (20 to 30 feet), and sites adjacent to the LCR FNC are dredged to the typical advanced maintenance depth of 48 feet. Transfer operations at a given location may be used once per year, more than once per year, or less frequently based on shoaling and dredge availability. Dredge placement operations are similar to in-water deep placement.
Ocean placement: Material dredged from the LCR FNC between RM 3 and RM 30 may also be placed in the ocean at the DWS ODMDS. The Corps only uses the site for Columbia River FNC dredge material if capacity was reached at other placement sites. Dredge placement operations are similar to in-water deep placement.
LCR FNC users may perform dredging to maintain their facilities which is a separate action from the DMMP-EIS. Information is available in Appendix L of the DMMP-EIS Plan which may be downloaded from https://usace.contentdm.oclc.org/digital/collection/p16021coll7/id/26366.
Project Schedule
Maintenance of the LCR FNC is ongoing. Implementation of the DMMP-EIS is scheduled to begin in 2025 and continue for at least 20 years.
Project Location
The area of analysis includes the LCR FNC, extending from RM 105.5 to the Mouth of the Columbia River at RM 3 and the transit corridor to the Deep-Water Site Ocean Dredged Material Disposal Site (DWS ODMDS) located 6 miles offshore of the Mouth of the Columbia River (i.e., the baseline from which the territorial sea is measured). See Figures 1-10. Plan view maps that show individual placement and structure sites are shown in DMMP-EIS Appendix E which may be downloaded from https://usace.contentdm.oclc.org/digital/collection/p16021coll7/id/26366.
Agency and Public Involvement
The Corps has prepared a Draft DMMP-EIS for the proposed action in accordance with the Council on Environmental Quality’s National Environmental Policy Act (NEPA) regulations found at 40 CFR Parts 1500-1508 and the Corps NEPA Implementation Regulations found at 33 CFR Part 230.
In addition, the content of this public notice fulfills the public notice requirements for discharges of dredged or fill material associated with Corps Civil Works operations and maintenance activities found in 33 CFR § 337.1. Any person who has an interest which may be affected by the disposal of this dredged material may request a public hearing. The request must be submitted in writing to the district engineer within the comment period of this notice and must clearly set forth the interest which may be affected and the manner in which the interest may be affected by this activity.
At the end of the 30-day public comment period for this public notification of proposed discharges under section 103 of the ODA and section 404 of the CWA, the Corps will consider all comments received or post marked by the expiration date of November 6, 2024.
The Corps published a Draft DMMP-EIS on August 26, 2024. Following public review, the Corps will prepare a Final DMMP-EIS and publish a Record of Decision (ROD).
The Draft DMMP-EIS and CWA Section 404(b)(1) Evaluation is available for download at: https://usace.contentdm.oclc.org/digital/collection/p16021coll7/id/26366
Environmental Coordination
The Corps is coordinating the proposed activity with multiple Federal, state and local agencies which include:
• National Marine Fisheries Service
• U.S. Environmental Protection Agency
• U.S. Fish and Wildlife Service
• Oregon Department of Land Conservation and Development
• Oregon Department of Environmental Quality
• Oregon State Historic Preservation Office
• Washington Department of Archaeology and Historic Preservation
• Washington Department of Ecology
Section 404 of the Clean Water Act
The decision whether to discharge dredged or fill material will be based on an evaluation of the probable impact including cumulative impacts of the proposed activity on the public interest. That decision will reflect the national concern for both protection and utilization of important resources. The benefit which reasonably may be expected to accrue from the proposal must be balanced against its reasonably foreseeable detriments. All factors which may be relevant to the proposal will be considered including the cumulative effects thereof; among those are conservation, economics, aesthetics, general environmental concerns, wetlands, historic properties, fish and wildlife values, flood hazards, floodplain values, land use, navigation, shoreline erosion and accretion, recreation, water supply and conservation, water quality, energy needs, safety, food and fiber production, mineral needs, considerations of property ownership and, in general, the needs and welfare of the people.
The Corps completed an analysis of the proposed discharge of dredged and fill material pursuant to the guidelines of Section 404(b)(1) of the Clean Water Act (40 CFR 230). This analysis is available at the preceding link under DMMP-EIS Appendix J.2.
The proposed DMMP includes use of the DWS ODMDS. Additional criteria pursuant to the Marine Protection, Research and Sanctuaries Act of 1972 appear in description of environmental compliance under “Section 103 of the Marine Protection, Research and Sanctuaries Act” below.
Section 401 of the Clean Water Act
Following public review of the Draft DMMP-EIS, the Corps will submit certification requests to the Oregon Department of Environmental Quality (DEQ) and Washington Department of Ecology for those discharges associated with the Draft Recommended Plan (DRP) that lack existing certification. Certification, certification with conditions, or denial would occur prior to the agency official signing the Record of Decision for the DMMP-EIS.
Section 106 of the National Historic Preservation Act
The Corps submitted area of potential effects (APE) consultation letters to Oregon State Historic Preservation Office (Oregon SHPO), Washington Department of Archaeology and Historic Preservation (DAHP), and Tribes on March 23, 2020, pursuant to 36 CFR § 800.4[1]). Oregon SHPO and DAHP concurred with the APE on July 16, 2020, and June 30, 2020, respectively. Section 106 consultation for DMMP is ongoing. On May 1, 2024, the Programmatic Agreement Among the U.S. Army Corps of Engineers, Portland District, the Advisory Council on Historic Preservation, the Oregon State Historic Preservation Office, and the Washington State Department of Archaeology and Historic Preservation Regarding the USACE Portland District Lower Columbia River Navigation Program, Oregon and Washington (Nav Program PA), was executed with Signatories being Advisory Council on Historic Preservation, Oregon SHPO, DAHP, and the Corps. The Nav Program PA allows the Section 106 review for the DMMP implementation to be completed in a phased approach. Prior to any DMMP project location being prepared, work on, or used, the Corps will follow the NHPA Section 106 review process identified in the Nav Program PA to determine effects to historic properties and mitigation, if adverse effects will occur.
Endangered Species Act
The Corps has determined that the DMMP-EIS proposed action would affect listed species under the jurisdiction of USFWS. The Corps initiated formal ESA Section 7 consultation with USFWS for the Continued Operations and Maintenance Dredging Program, which is being substantively modified by the DMMP-EIS proposed action, in a letter emailed on January 26, 2024. The Corps has obtained a Biological Opinion from the USFWS for the proposed action.
The Corps has also determined that the DMMP-EIS proposed action would affect listed species under the jurisdiction of NMFS. As a result, the Corps reinitiated formal ESA Section 7 consultation with NMFS for the Continued Operations and Maintenance Dredging Program, which is being substantively modified by the DMMP-EIS proposed action, on March 11, 2024. Formal consultation will result in a Biological Opinion from NMFS.
Coastal Zone Management Act
The Corps will prepare and submit a consistency determination to Oregon Department of Land Conservation and Development and Washington Department of Ecology. A summary of the draft consistency determination is provided in Appendix J.3 of the Draft DMMP-EIS. The consistency determination will be submitted to Oregon Department of Land Conservation and Development and Washington Department of Ecology at least 90 days prior to when the agency official will sign the Record of Decision for the DMMP-EIS.
Section 103 of the Marine Protection, Research and Sanctuaries Act
Under this Act the Corps must seek the EPA’s concurrence to transport and dispose dredged material at ocean dredged material disposal sites after considering impacts the proposed disposal would have on human health, welfare, or amenities; the marine environment and ecological systems; and economic potentialities of other ocean uses. Under the MPRSA, the Corps must also consider alternatives to dumping dredged material in ocean waters, which this DMMP does. The Corps would perform these evaluations (per 40 CFR Part 227) and seek EPA’s concurrence to use the Deep Water Site ocean dredged material disposal site (DWS) prior to transporting LCR FNC material to the site.
Based on an evaluation of the potential effects, which the failure to utilize this ocean disposal site will have on navigation, economic and industrial development, and foreign and domestic commerce of the United States, the EPA will make independent determinations of the need to dispose of the dredged material in ocean waters, in consideration of other possible methods of disposal and other appropriate locations.
The DWS was designated by the EPA on April 1, 2005 (70 FR 10041, March 2, 2005) and has been used since 2004. Pursuant to section 102(a) of the MPRSA, the EPA Regional Administrator applied the 5 general and 11 specific criteria used to determine the location, orientation, and size of the DWS (40 CFR § 228.5-228.6). The EPA determined that the location of the proposed site and the transport of suitable dredged material to the DWS would not unreasonably degrade or endanger human health, welfare, or amenities; or the marine environment, ecological systems, or economic potentialities. A 50-year planning horizon was used to size the DWS (2004 to 2053). The DWS provides a 4,293-acre, rectangular release zone (11,000 ft x 17,000 ft) surrounded by a 3,000-ft buffer. Water depths in the release zone range from 190 to 300 ft. Up to 40 ft of mounding is allowed at the site, providing a capacity of approximately 225 million cubic yards (Mcy).
The Corps is the primary user of the DWS, and the site has received material from the MCR FNC (RM -3.0 to +3.0) and LCR FNC (RM 3 to 29). In the last 20 years, the Corps has disposed over 21.3 Mcy of sand dredged from the MCR FNC and over 2.8 Mcy of sand from the LCR FNC (total: 24.1 Mcy). Less than 11% of the DWS’s 225 Mcy capacity has been used. With strategic beneficial use of dredged material in the LCR and around the Columbia River entrance, the Corps anticipates that the DWS lifespan will be much longer than 50 years, and no new ocean disposal site designation would be required under the proposed action.
In the Pacific Northwest Region, dredged material evaluations are performed in accordance with the Sediment Evaluation Framework for the Pacific Northwest (SEF) guidance (NWRSET 2018). The SEF is the Northwest’s regional implementation manual for the national sediment testing manuals: 1) Evaluation of Dredged Material Proposed for Ocean Disposal – Testing Manual ([aka Ocean Testing Manual] EPA/Corps 1991) and 2) Evaluation of Dredged Material Proposed for Discharge in Inland and Near-Coastal Waters – Testing Manual ([aka Inland Testing Manual] EPA/Corps 1998). The SEF and the national manuals ensure compliance with the MPRSA sediment testing regulations found at 40 CFR § 227.13 and the Clean Water Act sediment testing regulations found at 40 CFR §§ 230.60-230.61.
Dredged material from the LCR FNC is predominantly composed of clean sand. In the Corps’ May 2016 sediment characterization, the average sand content was greater than 97% sand and gravel, and less than 2.6% silt and clay. The total organic carbon content was also low at <0.3% (Corps 2017). Similar results were observed in the 1997 and 2008 characterizations of the LCR FNC sediments. In accordance with the SEF and the MPRSA sediment testing regulations found at 40 CFR § 227.13, chemical analysis was not required, because sand in the LCR FNC is part of the Columbia River bedload and is subject to strong currents. In these types of environments, sand is washed of the fine-grained material and is unable to bind contaminants, because the sand grains are inert. Based on repeated rounds of sediment characterization, the Corps and EPA have jointly determined that dredged material from the LCR FNC is suitable for unconfined, aquatic placement at both beneficial use sites and at ocean dredged material disposal sites. In accordance with the SEF, the Corps would continue to characterize sediments in the LCR FNC every 8 to 10 years to ensure they are suitable for unconfined, aquatic placement.
The MPRSA requires periodic dredged material disposal site monitoring and evaluation of the impact of dredged material disposal (40 CFR §§ 228.9-228.10). At the DWS, baseline surveys of sediment physical and chemical parameters and benthic infauna and epibenthic fauna were performed jointly by the EPA and Corps in 2001 and 2005. Monitoring surveys (led by the EPA with Corps assistance) were performed in 2013, 2014, and 2023. No adverse impacts from past dredged material disposal were observed. The EPA and Corps will continue to monitor the DWS every 8 to 10 years per the MPRSA’s monitoring and impact evaluation requirements.
Additional Information and Comments
Additional information and links to download the draft DMMP-EIS can be found at the Lower Columbia River Channel Maintenance website: http://www.nwp.usace.army.mil/lcrchannelmaintenance/.
Questions and comments regarding this public notice can be emailed to LCR-CMP-DMMP@usace.army.mil or by calling 503-808-4708. Please add “DMMP Clean Water Act” to the subject line.
Mailed comments on this notice must be postmarked by the above expiration date and sent to:
U.S. Army Corps of Engineers
Attn: CENWP-PME-E / DMMP-EIS
P.O. Box 2946
Portland, OR 97208-2946
In your response, please refer to the above public notice title and date. Should no response be received by the above closing date, a “no comment” response will be assumed.
Amy Gibbons
Chief, Environmental Resources Branch
US Army Corps of Engineers, Portland District
