Draft Suplemental EA - Rogue River Maintenance Dredging

Interested parties are hereby notified that the U.S. Army Corps of Engineers, Portland District (USACE) is seeking public comment on the Rogue River Maintenance Dredging draft Supplemental Environmental Assessment (SEA) in Curry County, Oregon. The draft Supplemental EA was prepared in accordance with the National Environmental Policy Act (NEPA), the Council on Environmental Quality’s NEPA regulations (40 C.F.R. parts 1500–1508), and the Corps’ NEPA regulations (33 C.F.R. part 230). 

USACE is proposing to conduct maintenance dredging of the Rogue River Federal Navigation Project. This SEA is intended to supplement the 2015 Environmental Assessment (EA), dated 30 JUN 2015, that disclosed maintenance dredging activities for the Rogue River Entrance Channel and Gold Beach Boat Basin Access Channel; however, did not include dredging a gravel bar located just upstream of the Boat Basin Access Channel that is causing significant infill of the navigation channel. Under the Proposed Action, the Corps proposes to increase the volume of material to be removed from the Entrance Channel and Boat Basin Access Channel during regular maintenance, and remove the gravel bar that is currently located just upstream of the Boat Basin Access Channel. All dredged material will be disposed at the Rogue River Ocean Dredged Material Disposal Site (ODMDS).

On 15 APR 2009, EPA Region 10 designated the Rogue River ODMDS offshore of Gold Beach, Oregon pursuant to section 102(c) of the MPRSA [74 FR 17406; 40 CFR 228.15(n)]. Corner coordinates of the Rogue River ODMDS are: 42°24′15.40″ N, 124°26′52.39″ W; 42°24′03.40″ N, 124°26′39.39″ W; 42°23′39.40″ N, 124°27′17.40″ W; 42°23′51.40″ N, 124°27′30.40″ W (NAD 83). Depths in the ODMDS range from approximately 50 to 90 ft. The Rogue ODMDS was designated for continuous use and is managed per the April 2009 “Site Management/Monitoring Plan for the Rogue River Ocean Dredged Material Disposal Site, Oregon.”

The Corps is the primary site user. The Corps has disposed approximately 1.3 million cubic yards of dredged material at the ODMDS since 1976 to maintain the Rogue River entrance channel and the access channel to the Gold Beach, Oregon boat basin. Until 2018, the U.S. Coast Guard (USCG) also maintained a small access channel to their Search and Rescue Detachment (SARDET) on the north bank of the Rogue River. This material was dredged by the Corps and disposed at the ODMDS. The USCG has moved their SARDET into the Gold Beach boat basin.

In the last decade, one ODMDS major monitoring event was performed on 13-17 SEP 2017. The oceanographic survey included sediment, water, and biological sample collection in the ODMDS and adjacent reference area. Data collected during the survey included: physical and chemical analysis; benthic infauna sample collection and species identification; epibenthic trawls and species identification; video sled transects and species identification; and in-situ water quality measurements. No adverse biological impacts were identified between the ODMDS and adjacent reference area.

Excessive mounding in the ODMDS has the potential to create hazardous navigation conditions. The joint goal of the Corps and EPA is to keep mounding below 10% of the baseline depth (measured in 09 MAY 1986). To monitor mounding at the ODMDS, 12 bathymetric surveys have been performed in the last decade (survey dates: 15 MAY 2012; 03 APR 2013; 12 MAY 2014; 05 MAR 2015; 01 JUN 2016; 06 JUL 2016; 27 MAY 2017; 04 JUN 2018; 01 AUG 2018; 29 AUG 2018; 05 JUN 2019; 06 JUN 2020). These surveys are compared to the 09 MAY 1986 baseline survey to monitor mounding at the site. The Corps recently performed a capacity analysis of the ODMDS. As of 06 JUN 2020 the ODMDS capacity is approximately 1 million cubic yards. Dredged material disposed at the Rogue River ODMDS is primarily composed of sand, gravel, and shell hash. 

The proposed transportation of this dredged material for disposing of it in ocean waters is being evaluated to determine that the proposed disposal will not unreasonably degrade or endanger human health, welfare, or amenities or the marine environment, ecological systems, or economic potentialities. In making this determination, the criteria established by the Administrator, EPA pursuant to section 102(a) of the ODA, will be applied. In addition, based upon an evaluation of the potential effect 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, an independent determination will be made of the need to dispose of the dredged material in ocean waters, other possible methods of disposal, and other appropriate locations.