# Yaquina Bay, Oregon Ocean Dredged Material Disposal Sites Evaluation Study and Environmental

Assessment

U.S. Army USACE of Engineers, Portland District

U.S. Environmental Protection Agency, Region 10

August 2012Yaquina Bay ODMDS Environmental Assessment and MPRSA Criteria Evaluation page i 

## Yaquina Bay, Oregon Ocean Dredged Material Disposal Sites Evaluation Study and Environmental Assessment



## Table of Contents

PURPOSE AND NEED ............................................................................................................. 1

BACKGROUND .................................................................................................................... .... 2 Statutory and Regulat ory Requirements ................................................................................. 2 Yaquina Bay Navigation ........................................................................................................ 4 Historic Offshore Disp osal (pre-1977) ................................................................................... 5 Offshore Disposal (1977-2000) .............................................................................................. 5 Offshore Disposal (2001-Present) .......................................................................................... 5

ANALYSIS OF ALTERNATIVES ........................................................................................... 6 Overview of Dredge Types .................................................................................................... 6 Overview of Disposal Options ............................................................................................... 6

No Action Alternative ......................................................................................................... ... 7 Upland/Beach Disposal Alternative ....................................................................................... 7 Estuarine Disposal Alternative ............................................................................................... 8 Ocean Disposal Alternatives .................................................................................................. 8 Disposal Off the Continental Shelf ..................................................................................... 8 Continued Use of Existing Sites ......................................................................................... 9 New Ocean Dredged Material Disposal Sites .................................................................... 9

OCEAN DUMPING SITE DESIGNATION PROCESS ......................................................... 10

Overview ...................................................................................................................... ........ 10 Defining a Zone of Siting Feasibility ................................................................................... 10 Yaquina Bay Zone of Siting Feasibility ............................................................................... 12 Conflict Matrix Analysis ...................................................................................................... 13 Eleven Specific Factors and Four General Cr iteria for Ocean Disposal Site Selection ....... 19 Application of Eleven Specifi c Criteria (40 CFR 228.6) ..................................................... 19 Application of Four Genera l Criteria (40 CFR 228.5) ......................................................... 25

DETERMINATION OF COMPLIANCE AND SELECTION FOR FORMAL DESIGNATION (40 CFR 227) ................................................................................................ 27

AFFECTED ENVIRONMENT ................................................................................................ 29 Physical Resources ............................................................................................................ ... 29

General ....................................................................................................................... ...... 29 Yaquina Bay Sediments ................................................................................................... 30

ODMDS Sediments .......................................................................................................... 30 Oceanographic Circulation ............................................................................................... 31 Geology ....................................................................................................................... ..... 32 Biological Resources .......................................................................................................... .. 32

Introduction .................................................................................................................. .... 32Yaquina Bay ODMDS Environmental Assessment and MPRSA Criteria Evaluation page ii Plankton and Fish Larvae ................................................................................................. 32

Benthic Invertebrates ........................................................................................................ 33 Fish and Epibenthic Species ............................................................................................. 34

Commercial and Recreationa l Fisheries Economics ........................................................ 35

Wildlife ...................................................................................................................... ....... 35 Threatened or Endangered Species .................................................................................. 35

Socio-Economic Resources .................................................................................................. 37

Cultural Resources ............................................................................................................ 37

Recreational Uses ............................................................................................................. 38

Commercial Uses .............................................................................................................. 38

ENVIRONMENTAL EFFECTS .............................................................................................. 38 Physical Resources ............................................................................................................ ... 38 Biological Resources .......................................................................................................... .. 39

Socio-Economic Resources .................................................................................................. 40

SUMMARY OF COORDINATION ........................................................................................ 40

Federal Action ................................................................................................................ ...... 40 Endangered Species Act ....................................................................................................... 41 Magnuson-Stevens Act and Marine Mammal Protection Act .............................................. 41 Coastal Zone Management Act ............................................................................................ 42

National Historic Preservation Act ....................................................................................... 42

Tribal Consultation ........................................................................................................... .... 42

SELECTION OF OCEAN DISPOSAL SI TES FOR FORMAL DESIGNATION ................. 43

LITERATURE CITED ............................................................................................................. 44

List of Figures

Figure 1. Yaquina North and S outh Ocean Disposal Sites ........................................................ 3 Figure 2. Phases of the S ite Designation Process .................................................................... 11 Figure 3. Conflict Matrix Legend ............................................................................................ 17

List of Tables

Table 1. ODMDS Conflict Matrix for Inte rim and Nearshore Section 103 Sites ................... 14

Table 2. ODMDS Conflict Matr ix for the North Site ............................................................. 15

Table 3. ODMDS Conflict Matr ix for the South Site ............................................................. 16

Technical Appendices

Appendix A – Living Resources Appendix B – Physical Proce sses and Geological Features Appendix C – Sediment and Water Quality Appendix D – Cultural Resources Appendix E – Recreational Resources Appendix F – Site Management and Monitoring Plan (SMMP)Yaquina Bay ODMDS Environmental Assessment and MPRSA Criteria Evaluation page 1 

## Yaquina Bay, Oregon Ocean Dredged Material Disposal Sites Evaluation Study and Environmental Assessment

PURPOSE AND NEED

This Ocean Dredged Material Disposal Si te (ODMDS) Evaluation and Environmental Assessment has been jointly prepared by the U.S. Army Corps of Engineers (USACE) and U.S. Environmental Protection Agency (EPA). Th e purpose of this evaluation is to provide documentation in support of final designation by EPA of two ODMDSs needed for long-term use by the authorized Yaquina Bay navigation projects . This evaluation determined that the North and South ODMDS offshore of Yaquina Bay, Ore gon, fully meets all criteria and factors set

forth in Parts 228.5 and 228.6 of Title 40 Code of Fe deral Regulations (CFR). These regulations were promulgated in accordance with the criteri a set out in Sections 102 and 103 of the Marine Protection, Research and Sanctu aries Act of 1972. Further, th is document provides sufficient information to determine compliance with the Na tional Environmental Policy Act, the National Historic Preservation Act, the Coastal Zone Mana gement Act, and Endangered Species Act. Use

of the sites would be for dis posal of material dredged for operation and maintenance of the federally authorized navigation project at Yaquina Bay, as well as through separate Section 103 permit evaluation for disposal of dredged material from other dredging projects.

The availability of ODMDSs in the vicinity of Ya quina Bay are necessary to maintain safe deepdraft navigation through authorized federal channels and permitted actions. The historic Interim and nearshore Section 103 site experienced mounding, generating a potentially hazardous navigation safety condition, and had limited site capacity to receive future dredge material disposals. Commercial shippers , crab fishermen, and the U.S. Coast Guard expressed concern

over this situation to both the USACE and EPA. While the situation may not have constituted an imminent hazard to life and property, which w ould warrant an emergency, the EPA and USACE agreed that prudent management action was required in order to prevent any further adverse conditions from developing. Effo rts were undertaken by the fede ral government to temporarily expand the historic Interim and nearshore Sectio n 103 sites in 1998 and to manage distribution of the maintenance dredged material within the av ailable site while seeking a more permanent management solution. The need for ocean dumping and implementation of a management solution by USACE and EPA were at a point where the ability to maintain the Yaquina Bay project was at risk. Unless the Yaquina Bay pr oject can be maintained, continued commercial use of the existing navigation ch annels at their authorized depth would not be possible.

The rough seas encountered at the Yaquina Ba y entrance preclude the safe and efficient operation of any dredge other than a hopper dredge. Upland disposal of dredged material from a hopper dredge operation is not economical due to the need to double handle the material and sufficient upland capacity is unavailable. Dis posal of material dredged from Yaquina Bay, therefore, must occur at an in-water site.Yaquina Bay ODMDS Environmental Assessment and MPRSA Criteria Evaluation page 2 While it is possible to dredge and transport material back into the estuary for disposal, there is a lack of suitable estuarine and upl and disposal sites. Further, es tuarine habitats are unique and far less extensive than are sandy nearshore oceanic hab itats. Estuarine disposal would cause greater adverse environmental impacts than would ocean disposal.

Table B-1 in Appendix B provides dredged mate rial volumes estimated for the Yaquina Bay federal navigation project from 1928 to 2010. Futu re estimated total disposal quantity for the long-term maintenance dredging of the navigatio n channel is expected to remain relatively

constant.

Though the volume is expected to be minor co mpared to the federal dredging volumes, the designated sites may receive material dredge d by non-USACE entities and disposed under specific permits issued by USACE. With the f undamental need for ocean dumping having been demonstrated, USACE and EPA had to consider the needed dispos al capacity which influences the number and/or size of site(s). The USACE conducts their site capacity modeling based on a 20-year outlook (Appendix B).

Given their modeling results, tw o ocean disposal sites, the North ODMDS and South ODMDS, are designated (Figure 1). Due to their size, disposal capacity was considered sufficient for approximately 20 years or more for each. These sites replace the nearsh ore Section 103 Site in the government’s preferred action for management of dredged material at Yaquina Bay. The need for designation of these sites pursua nt to 40 CFR 227 Subpart C is considered

demonstrated.



### BACKGROUND

Statutory and Regulatory Requirements

The Marine Protection, Research and Sanctuaries Act of 1972, as amended (MPRSA), also known as the Ocean Dumping Act, was passed in r ecognition of the fact th at the disposal of material into ocean waters could potentially resu lt in unacceptable adverse environmental effects. Under Title I of the MPRSA, the EPA and USAC E were assigned responsibility for developing and implementing regulatory programs to ensure that ocean disposal would not “... unreasonably degrade or endanger human health, welfare, or am enities, or the marine environment, ecological systems, or economic potentialities.”

The EPA administers and enforces the overall progr am for ocean disposal. Under Section 102 of the MPRSA, EPA in consultation with USACE establ ished environmental criteria that are to be addressed before an ocean dredge d material disposal permit can be granted. The USACE issues permits for the transportation of dredged materi al for the purpose of ocean disposal, after consultation with EPA, which are in compliance with these criteria. While USACE does not administratively issue itself a permit, the requiremen ts that must be met before dredged material derived from USACE projects can be discharged in to ocean waters are the same as those where a permit would be issued.Yaquina Bay ODMDS Environmental Assessment and MPRSA Criteria Evaluation page 3 Figure 1. Yaquina North and South Ocean Disposal SitesYaquina Bay ODMDS Environmental Assessment and MPRSA Criteria Evaluation page 4 The MPRSA criteria (40 CFR, Part 228) states that final site designation under Section 102(c)

must be based on environmental studies of each site and on historical knowledge of the impact of dredged material disposal on areas similar to su ch sites in physical, chemical, and biological

characteristics. General criter ia (40 CFR 228.5) and specific fact ors (40 CFR 228.6) that must be considered prior to site designation are descri bed and evaluated in th is evaluation. Related federal statutes applicable to the site desi gnation process include th e National Environmental Policy Act of 1969, as amended; the Coastal Zone Management Act of 1972 as amended; the

National Historic Preservation Act and the Endangered Species Act of 1973, as amended. As required by Section 104(a)(3) of th e MPRSA, ocean disposal of dr edged material can occur only at a site that has been designate d to receive dredged material. Pursuant to Section 102(c), the EPA has the responsibility for site designation. Section 103(b), while en couraging use of EPAdesignated sites where feasible, does provide for alternative site selection by the USACE when a suitable EPA-designated site is not available. However, the same ocean dumping criteria (40 CFR 228.5-228.6) are used in the evaluation process th at leads to alternativ e site selection and

the EPA must concur with the selection.

An EPA-designated site requires a site management and monitoring plan. Use of the designated site is subject to any restrictions included in the management and monitoring plan and EPA’s designation regulations. These re strictions are based on an in-d epth evaluation of the site pursuant to the regulations (40 CFR 220-229) and potential disposal activity as well as public review and comment. Designation of an ODMDS in itself does not result in disposal of dredged material. A separate evaluation of the suitability of dredged material for ocean disposal must be undertaken for each proposed use of the site by either the USACE or non-USACE permit applicant. Typically, as in this case, this i nvolves evaluation of the sp ecific disposal activity under the Criteria, circulation of a Public Notice (which can include multi ple years of use), and specific coordination with stake holders as well as concurrenc e by the appropriate EPA Region.

Yaquina Bay Navigation

Yaquina River enters the Pacifi c Ocean near the city of Ne wport, Oregon, approximately 115 miles south of the Columbia River. Yaquina Ba y is the fourth largest estuary in Oregon. The estuary is fed mainly by the Ya quina River, which drains 253 square miles and is 58.8 miles

from its mouth to headwaters. The Portland Dist rict, USACE of Engineers has been responsible for maintenance of navigable wa terways of the north Pacific co ast since 1871. The need for improved navigation controls in the Yaquina Bay estuary began w ith the founding of a port city at Yaquina. Because of the navigation need, two rubble-mound jetties were constructed in 1896, and Congress authorized dredging in the bay in 1919. The federally auth orized project includes jetties, groins, and river channel ou tside the scope of the present study.

The Yaquina Bay federal navigation project was authorized for the following purposes:

• Provide an entrance channel, which would allo w the upriver channel to be fully utilized.

• Decrease tide-caused delays for commercial ships crossing the bar.

• Provide improved safety by reducing the po ssibility of commercial ship grounding and a channel that allows for compatible use by commercial and noncommercial vessels.

• Provide mooring facilities for small boats th at take advantage of project facilities.Yaquina Bay ODMDS Environmental Assessment and MPRSA Criteria Evaluation page 5 • Permit barge and small boat traffic upstream to river mile (RM) 14.

• Provide a harbor of refuge.

The federally authorized entrance channel at Ya quina extends from RM -1 to RM 4.4. Up to 370,000 cy of material is dredged from the entr ance channel annually. Maximum dredge depth is -45 feet (RM -1 to RM 0), -32 feet (RM 0 to RM 2+20), and -20 feet (RM 2+20 to 4+20) as measured from MLLW, including advanced maintenance dredging.

The South Beach Marina access channel is approx imately 2,035-feet long and runs from Yaquina RM 1 to the marina. Dredging will occur once ever y 5 to 8 years. Maximum dredge depth is -11 feet, as measured from MLLW, including 1 foot of advanced maintenance dredging. Up to 25,000 cy of material is re moved per dredging effort.

The federal navigation channel is approximately 10 miles long and extends from RM 4 to 14, including Depot Slough; however, only Depot Slough is maintained. Dredging typically occurs once every 5 to 8 years. Maximum dredge depth is -12 feet, as measured from MLLW, including 2 feet of advanced maintenance dred ging. A maximum of 100,000 cy of material is removed per dredging effort.

Historic Offshore Disposal (pre-1977)

Prior to the Interim Site receiving designation in 1977, the USACE had historically used the general area for dredged material disposal since at least 1916. Approximately 200,000 cubic yards (cy) annually were dredged annually from the project from 1919 to 1968 when the project was deepened to its present depth. USACE record s of dredging the entrance bar, inner channel, and turning and small boat basins from 1959 to 1969 (excluding 1968) show that 247,737 cy was fairly typical of quantities remove d (Percy et al. 1974). Interim site designations in 1977 were an attempt by EPA to document and establish coordi nates for historically used USACE disposal

sites.

Offshore Disposal (1977-2000)

In January 1977, the Interim Site received its interim designation when EPA issued the final Ocean Dumping Regulations (40 CFR 228). Be tween 1977 and 1985, material was placed in the EPA Interim Site. Due to the increased mounding at the Interim Site and its potential adverse effect on navigation safety, in 1986 the USACE se lected an alternate ODMDS under its Section 103 authority. The 1986 nearshore Section 103 Site was located to the north and further offshore of the interim site in water depths ranging fr om 50 to 102 feet (see Figure 1). Between 1986- 2000, dredged material was placed in the nearshor e Section 103 Site sele cted by USACE. Due to mounding, the nearshore Section 103 site was expanded in 1998 to include the outer twothirds of the EPA Interim S ite; material was placed in this expanded area in 1999.

Offshore Disposal (2001-Present)

In 2001, the USACE Portland Dist rict, under its Section 103 au thority, selected two new ODMDSs (North Site and South Site) for the dispos al of dredged material. EPA concurred in a July 19, 2001 letter for the first 5-year period. The North Site was first used in 2001 so expiredYaquina Bay ODMDS Environmental Assessment and MPRSA Criteria Evaluation page 6 in 2006 with an option for an additional 5 years. EPA issued a second Section 103 concurrence letter dated April 27, 2007 for cont inued use of the North Site. This allowed use of the North Site until the end of the 2011 dredging season.

Between 2001 and 2009, all dredged material was pl aced in the northern half of the Section 103 North Site. Maximum mound height in 2007 reached 5 feet, while in 2008 it reached 6 feet and in 2009 the maximum mound height reached 10 feet relative to July 2001. In 2009-2010 material from Depot Slough was dredged by clamsh ell and barged to the North Site. Also a portion of the material from the Yaquina Bay federa l project was placed in the southern half of

the North Site. Portions of th e north half of the North Site have mounded 10-12 feet above the 2001 baseline bathymetry. All dredged material was placed in the southern half of the North Site during the 2011 dredging season. No material has been placed in th e South Site as of the end of the 2011 dredging season.



### ANALYSIS OF ALTERNATIVES

Overview of Dredge Types

Three basic types of dredges exist: mechanical dredges (which include clamshell), pipeline or suction dredges, and hopper dredges. Hopper dr edges are self-propelled, seagoing vessels and are the only type of dredge th at can work effectively in r ough open water. Larger hopper dredges can work in sea swell c onditions to about 10 feet. Hoppe r dredges are very mobile and can move quickly to minimize interference with navigation traffic and can adjust to rapidly changing weather and sea conditions. Pipeline an d clamshell dredges are typically not selfpropelled and cannot operate safely and effectiv ely in conditions with waves greater than 3-4 feet. They also are unable to handle strong curren ts such as those that oc cur during tidal shifts. Both pipeline and clamshell dredges employ spuds and/or anchors to station them in the work area and cannot be quickly moved to accommodate tr affic, changing weather, or sea conditions. The different dredge types do not necessarily preclude use of the different disposal options. For example, sediments removed by pipeline can be placed into a barge and the material dumped into the ocean. However, greater effi ciencies can be realized by ma tching the dredge type to the disposal option [also see section on Defini ng a Zone of Siting Feasibility (ZSF)].

The typically rough seas and strong currents enc ountered at the entrance to the Yaquina Bay project are too dangerous for safe operation of pipeline or mechanical dredges and hopper dredges must be used. Pipeline and mechani cal dredges can operate within the estuary to maintain the main and smaller navigation channels as well as harbor or marina areas. Hopper dredges also have been used historically to maintain the Coos Bay, Columbia River, and the

other small coastal navigation channels.

Overview of Di sposal Options

The alternatives for ocean dumping of dredged ma terial from the Yaquina Bay project that were considered by the EPA and USACE include no action, upland/beach disposal, and estuarine disposal. The alternatives considered under the ocean disposal option include disposal off the continental shelf, continued use of existing site s, and designation of new ocean disposal sites.Yaquina Bay ODMDS Environmental Assessment and MPRSA Criteria Evaluation page 7 No Action Alternative

Within the context of ocean dumpi ng alone, the no action alternativ e would be for EPA to refrain from designating new ODMDSs for the placement of dredged material. One option under this alternative would include continuing use of th e existing Section 103 Site. However, the site already has mounded and further use is restrict ed by the USACE and EPA. By regulation, if there are no suitable EPA designated sites, then th e USACE has the authority to select alternate

sites under its MPRSA Section 103 authority, although the selecti on would still be subject to meeting the criteria and would have to receive the concurrence of EPA. As the substantive requirements for information and evaluation of a Section 103 action are si milar to those of an EPA formal designation under Sectio n 102. However, use of a Section 103 site is limited to 5 years with one possible 5-year extension. ODMDS “selections” by the USACE are temporary and offer only a stopgap solution.

The most plausible outcome of the no action alte rnative is that existi ng and proposed navigation projects may be terminated. Future tempor ary actions are not seen as desirable by the government or the private sector. None of th e disposal options under the no action alternative meet the needs for long-term maintenance of the Yaquina Bay project. Terminating maintenance dredging would reduce the safety of the channel for both small and large ships, and would have an adverse economic impact to the Pacific Nort hwest and the nation. For these reasons, the no action alternative is judged by both the USACE and EPA to be an unacceptable alternative and has been dropped from further evaluation.

Upland/Beach Disposal Alternative

Upland disposal for all of the material from the Yaquina Bay project is not feasible for operational, economic, and environmental reasons. Material from the entrance must be dredged with a hopper dredge. Upland disposal would requi re suitable pump-out faci lities or construction of an in-bay sump. Stockpiling of material and re-dredging and transporting of the material to upland sites is not considered environmentally acc eptable or economically feasible. In addition, there are no known suitable upland ar eas in the immediate vicinity of the estuary with sufficient capacity to meet long-term disposal needs. Most of the lands adjacent to the ocean and estuary are wetlands, or too steep, or are already developed (including state park lands). On an irregular basis, small quantities are dredged from the Sout h Beach Marina with a small pipeline dredge and upland disposal. Material from Depot Slough dredged unde r permit has also gone upland, but again the quantities dredged we re small. No suitable upland ar ea that could be accessed by a hopper dredge or that could accept the large vol ume of material annually dredged for the Yaquina Bay project has been identified.

Placement of dredged material directly on ocean beaches by hopper dredge is not practicable at Yaquina Bay. As with upland disposal, direct placement on the beach would require suitable pump-out facilities or construc tion of an in-bay sump. Stockp iling of material and re-dredging and transporting it directly to the beach with a pipeline dredge is not considered environmentally acceptable or economically feasible.

Placement of material offshore in the active litto ral zone at Yaquina Bay is complicated by the unique neritic reef structure. Seaward of about -40 feet, the sand movement by wave action isYaquina Bay ODMDS Environmental Assessment and MPRSA Criteria Evaluation page 8 influenced by near-bottom and downslope m ovement. At Yaquina, the -40 foot boundary coincides with the offshore reef complex for se veral miles north and south of the jetties. Movement of sand seaward of the reefs and deeper than about -40 feet is predominantly offshore. Away from the tidal exchange effects of the entrance channel bottom, movement may have either a northward component or southwar d. There is no onshore sand movement beyond Yaquina Reef and no sand movement around the je tties toward the north. This limits sand transport into the nearshore north of the jetties so there is a potential for net loss of material. This is supported by significant shoreline eros ion throughout much of the area from the North Jetty to Yaquina Head.

The shoreline north of Yaquina Head has also experienced erosion to the point portions of Highway 101 have failed. Some portions of the highway have been moved. While there is a recognized need in the area for beach nourishment, no local sponsor has b een identified. Further

studies for suitable nearshore feeder berms that would feed the beach would be required. These studies are beyond the scope of this Yaquina Ba y ODMDS site evaluation study. Because of the need to dredge the Yaquina Bay federal naviga tion project with a hopper dredge, the lack of sufficient upland or beach nourishment disposal s ites, and no identified local sponsorship for a beneficial use option, the use of upl and or beach disposal as an a lternative to ocean disposal is not considered to be practicable.

Estuarine Disposal Alternative

Estuarine habitat is limited and environmentally sens itive. The estuary is comprised primarily of its major tributary, the Yaquina River, which drains 252 square miles and is relatively short with a length of 58.8 miles. Tideland s cover between 35% and 61% of the total area that are mostly within three tide flats at Sally ’s Bend, King’s Slough, and the area between Idaho Point and the

Marine Science Center. From its mouth to the head of high tide at RM 26, the river has one major tributary (Elk Creek at RM 22.3) and about 30 smaller creeks and sloughs. No suitable estuarine disposal areas that could be accessed by a hopper dredge or acce pt the large volume of material annually dredged have been identi fied. In 1994 however, several hopper loads of dredged material consisting primarily of larg e shell hash from RM 1.5 were placed at an estuarine location near RM 8. The Oregon Depart ment of Fish and Wildlife (ODFW) requested that this dredged material be placed at selected locations in the upper estuary for the purpose of restoring native oyster habitat.

Ocean Disposal Alternatives

Based on evaluation of the alternative solutions previously discussed, continued disposal of dredged material from the Yaquina Bay project into the ocean is necessary and unavoidable. Options include disposal of the material off th e continental shelf, use of previous disposal ODMDSs, and the designation of new ODMDSs.

Disposal Off the Continental Shelf

The direction for EPA to locate dump sites off the continental shelf is on e of the five general criteria [40 CFR 228.5(e)]; however, that direction is subject to a determination of feasibility. At Yaquina Bay, potential disposal areas located off the continental shelf would be at least 20Yaquina Bay ODMDS Environmental Assessment and MPRSA Criteria Evaluation page 9 nautical miles offshore in water depths of 600 fe et or greater. This distance is well beyond the economical haul distance for hopper dredges worki ng the Yaquina Bay project given the size of the west coast hopper fleet (see the sec tion describing development of the ZSF).

Transporting dredged material off the con tinental shelf presents potentially significant environmental concerns. Benthic and pelagic ecosystems near the shelf contain important fishery resources and the effect s of disposal operations on th em are not well understood. Finegrain sediment and rocky habitats would be dire ctly impacted by disposal. These deep-water areas are stable and generall y not disturbed by wave acti on or sediment movement. Consequently, the benthic invertebrate communiti es in these deep, offshore environments are adapted to very stable conditions and would be less able to survive disturbance from the immediate impact of disposal and the long-term alteration of substr ate type. Little is known of the ecology of benthic communities on the con tinental slope; however, disposal onto those communities would cause severe and long-term imp acts. Bottom gradients can be 5% to 25% on the continental slope, making accumulated unconso lidated sediments susceptible to slumping. Deposited sediments could be tr ansported long distances downsl ope as turbidity currents and offshore by near-bottom currents, potentially aff ecting organisms outside of any designated site.

The cost for site evaluation nece ssary to designate a site and s ubsequent baseline and monitoring, along with unanswered environmental concerns a bout the effects of disposal in such areas, makes off-shelf disposal undesirabl e as well as infeasible . Further, disposal off the continental

shelf would remove natural sediments from the near shore littoral transport system, a system that functions with largely non-renewable quantities of sand in Oregon. While the loss of the present volumes of USACE dredged material are unlikely to result in disruption of the mass balance of the littoral system, the State of Oregon is already experiencing erosion/accretion patterns that are adversely impacting beaches, spits, we tlands, and other shoreline habitats.

Use of Previous ODMDSs

The small size of the historic Interim and nearsh ore Section 103 Sites and the large quantity of material requiring ocean disposal resulted in mounding of material and potential navigation hazards (see the previous section on No Action A lternative). That situation would persist and become worse with continued use without significa nt expansion. A return to disposing at those sites would result in mounding and impacts to navi gation. Local fishers, their associations, the Port of Newport, and the Coast Guard expresse d strong opposition to the use of the nearshore Section 103 Site and its surrounding area. Use of the expanded nearshor e Section 103 Site, the result of the USACE Section 103 action in 1998, e xpired in 2003. Because of its limited size, continued mounding, and navigational safety con cerns, the nearshore Se ction 103 Site was not considered by USACE and EPA as suitable for long-term use.

New Ocean Dredged Material Disposal Sites

Based on evaluation of the alternatives previo usly discussed, USACE a nd EPA concluded that the designation of the North and South ODMDS is necessary to meet the long-term disposal needs for Yaquina Bay.Yaquina Bay ODMDS Environmental Assessment and MPRSA Criteria Evaluation page 10 

### OCEAN DUMPING SITE DESIGNATION PROCESS

Overview

The dumping of material, including dredged sediments, into the ocean is permitted only at sites

or in areas selected to minimize the interference of disposal activities with other activities in the marine environment. Formal designation of ocea n dumping sites is the responsibility of EPA as stated in 40 CFR 228 of the ocean dumping regul ations. The process followed by EPA, Region 10, and USACE for the Yaquina Bay project genera lly follows the site designation procedures developed by a joint task force of EPA and USACE personnel titled, General Approach to Designation Studies for Ocean Dre dged Material Disposal Sites (EPA and USACE 1984).

The procedures utilize a hierarchical framew ork that initially establishes the broadest economically and operationally feasible area of c onsideration for site location. A step-by-step sequence of activities is then conducted to eliminat e critical and/or unsuitable subareas. Further evaluation of alternative sites (candidate sites) within this area entails various levels of assessment as suggested by the sens itivity and value of critical re sources or uses at risk, and potential for unreasonable adverse impact presented by the dredged material to be disposed. The site designation criteria at 40 CFR 228.5 and 228.6 are applied to the in formation assembled through this process, and a final site or sites are selected and proposed for formal designation.

The site designation process is structured into three major phases (Figure 2). Phase I includes the delineation of the general ar ea being considered for locating a site and the identification and collection of the necessary information on critic al resources and uses and on the physical and environmental processes for the area. Reasonable distance of haul is the determining factor and will be affected by considerations such as available dredging equipment, energy use constraints, costs, and safety considerations. Then a prelim inary analysis, based on available data, is applied to identify and map reach boundaries for critical resources, as well as areas of incompatibility. Such critical areas and resources may include cl ustered areas of geogra phically limited habitats, fisheries and shellfisheries, navigation la nes, beaches, and marine sanctuaries.

Phase II primarily involves the elimination of sensitive and incompatible areas, determining additional data needs, and identification of candidate sites within the area based on the information collected and processed in Phase I. Phase III primarily i nvolves the evaluation of candidate sites, selection of a proposed site or sites for designation, and the development of management strategies.

Defining a Zone of Siting Feasibility

Joint EPA and USACE guidance for site designa tion suggests establishing a ZSF, as ocean disposal sites must be located within an operationally and economically feasible distance from the point of dredging (EPA a nd USACE 1984). By doing so, st udy efforts can be focused on areas that will actually meet project needs.Yaquina Bay ODMDS Environmental Assessment and MPRSA Criteria Evaluation page 11 Figure 2. Phases of the Site Designation ProcessYaquina Bay ODMDS Environmental Assessment and MPRSA Criteria Evaluation page 12 Presently, the availability of dredging equipment is a major constraint that must be considered in the determination of a ZSF for any navigation pr oject, but particularly so for ocean entrance projects on the west coast of the United Stat es. The Jones Act precludes the USACE from contracting with foreign-owned vessels, limiti ng the accessible pool to U.S. Government or privately owned (contract) equipment. The USACE evaluates the availability of U.S. Government or contract equipment annually and allocates the use of government dredges for the nation. As described previousl y, hopper dredges are the only f easible equipment for dredging

most ocean entrance channel/bar situations.

Hopper dredge availability on th e west coast has been limited. Many hopper dredges working in

the United States are often committed to maintaini ng projects on the Atlantic and Gulf of Mexico coasts and are not available for use elsewhere, except perhaps on an emergency basis. As a result, there are typically three hopper dredges working on the west coast that can work safely at Yaquina Bay and these dredges must also ma intain other projects in Oregon, Washington, California, as well as occasionally Hawaii a nd Alaska. Additional capability could occur through construction of new dredges by the U.S. Government or private industry.

Weather is also a significant limiting factor for dredging and ocean dumping of material along

the west coast that must be considered in deve lopment of the ZSF. Typically, hopper dredges are able to work safely in Pacific Northwest coasta l waters, including the Yaquina Bay project, from May to mid-October, with a very high and cons istent probability of down time due to rough seas

or other adverse weather conditions at either end of that perio d. During this same May through October window, all other west coast entrance dredging also must occur.

Yaquina Bay Zone of Siting Feasibility

The amount of time necessary to maintain a coasta l project (exclusive of weather downtime) is a function of dredging a hopper full of material (loading), then tran sporting that material to and placing it at the disposal site(s). This is calle d “cycle time” and the cycle time can be different for each dredge. Loading time is essentially fixe d based on the characteristics of the sediments being dredged, the dredge itself (pumps, size of hopper, drag arms, etc.) and the dredging site conditions. The time to discharge ma terial also is basically fixed for a given dredge and the type of material. Transport time depe nds primarily on the haul distan ce to the disposal site because the speed of different ho pper dredges is similar.

Thus, the critical element for new construction or maintenance dredging is haul distance between the dredging site and disposal site from both a time and cost pe rspective. A significant haul distance will affect the ability to construct or maintain the individual project and very probably would have repercussions on the ability of US ACE to maintain other west coast projects.

The 1985 evaluation study (USACE 1985) calculated a 2 nautical mile ZSF for the project. This calculation was based upon the removal at that time of up to 700,000 cy of dredged material using both contract and government dredges. A total of 60 days for a contract dredge and 10 days for a government dredge were allocated fo r the work at Yaquina Bay. Production capability with a 2 nautical mile ZSF was determined to be 10,000 cy per day.Yaquina Bay ODMDS Environmental Assessment and MPRSA Criteria Evaluation page 13 Under current and foreseeable condi tions at the project, the estimat ed volume of material to be removed annually is expected to remain at an average of 310,000 cy. Based upon workload, available funding and other constraints, th e government owned hopper dredge YAQUINA is typically available 35 days at the Yaquina Bay pr oject or a contract dred ge is available for a similar length of time. This translates into an 8,943 cy per day average production requirement. The rated capacity for the YAQUINA is 1,000 cy. Load time typically is around 1 hour for most projects; however, Yaquina Bay is the d eepest project that th e YAQUINA dredges and productivity is likely less. Dump time is 5 to 10 minutes. The dredge typically works 24 hours per day except for Thursday when crews are changed.

The ZSF can be calculated as follows:

Assume 9 loads per day (8,943 cy ÷ 1,000 cy/load = 8.9 loads)

Load time (1 hour) + Dump time (0.17 hour) = 1.17 hour/load or 10.5 hours/day

24 hours/day - 10.5 hours/day = 13.5 hours/day fo r transit to/from th e disposal site

13.5 hours/day ÷ 9 loads/day = 1.5 hour tran sit time for one round trip

1.5 hour ÷ 2 = 0.75 hour transit time for one way

0.75 x 6 nautical mile vessel speed = 4.5 nautical miles

Therefore, the outer limit of the ZSF as defined by the capacity of the available dredging plant, average annual dredging quaintly, and limited dr edging time period is 4.5 nautical miles for the Yaquina Bay project.

Conflict Matrix Analysis

The USACE developed a conflict matrix format to simplify and consolidate scoring for the general and specific site criter ia review process. The USACE and EPA have employed the

conflict matrix method since 1984. Each area of consideration on the conf lict matrix addresses at least one general or specific criterion. Tables 1 through 3 are conflict matrices developed to compare the historic Interim and nearshore Section 103 site to th e new sites and their potential conflicts with the four general and eleven specific site selection criteria. In general, the new sites

result in fewer conflicts with th e criteria than the historic Interi m and nearshore Section 103 site. A legend defining the matrix categories follows the tables (Figure 3).Yaquina Bay ODMDS Environmental Assessment and MPRSA Criteria Evaluation page 14 Table 1. ODMDS Conflict Matrix for Interim and Nearshore Section 103 Sites



## Interim and Nearshore Section 103 Sites

AREA OF

CONSIDERATION 1/CONFLICT2/POTENTIAL CONFLICTNO CONFLICTBENEFICIAL USE
COMMENTS RELEVANT
SPECIFIC
FACTORS

Eleven Specific

Factors 3/

(40 CFR 228.6) RELEVANT
SPECIFIC
FACTORS

Four General

Criteria 4/

(40 CFR 228.5)

1. Unusual Topography/Unique

Bottom Features X Close proximity to neritic reef. 1, 6, 8, 11 a

2. Physical Sediment Compatibility X Similar material though ~5% is finer. 3, 4, 9 b, d

3. Chemical Sediment Compatibility X 3, 4, 7, 9 a, b, d

4. Influence of Past Disposal X Excessive mounding. 5, 7, 9, 10 a, b, d

5. Living Resources of Limited

Distribution X Kelp and reef life forms could be affected by sediment transport. 2, 3, 6, 8, 11 a, b, d

6. Commercial Fisheries X 2, 8 a, b

7. Recreational Fisheries X Minor conflict with dredge traffic. 2, 8 a, b

8. Breeding/Spawning Areas X Resident and migrating fish use the

area. 2, 8 a, b

9. Nursery Areas X Juvenile flatfish. 2, 8 a, b

10. Feeding Areas X Feeding areas could be affected. 2, 8 a, b

11. Migration Routes X Anadromous fish route. 2, 8 a, b

12. Critical Habitat of Threatened or Endangered Species X Designated critical habitat for southern green sturgeon and leatherback sea

turtle. 2, 8 a, b

13. Spatial Distribution of Benthos X 2, 8, 10 a, b

14. Marine Mammals X Feeding area. 2, 8 a, b

15. Mineral Deposits X 1, 8 a, b

16. Navigation Hazard X Wave amplification due to excessive mounding. 1, 8 a, b, d

17. Other uses of Ocean (cables, pipelines etc.) X 8 a, b, d

18. Degraded Areas X 4, 6, 7 a, b, d

19. Water Column Chem./Phys.

Characteristics X 4, 6, 9 a, b, d

20. Recreational Uses X See item 7. 2, 8, 11 a, b, d

21. Cultural/Historic Sites X 11 b

22. Physical Oceanography:

Waves/Circulation X Wave amplification due to mounding, potential current effects. 1, 3, 6, 7 a, b, d

23. Direction of Transport/Potential

for Settlement X Reintroduces sand to littoral budge t. 1, 3, 6, 7 a, b, d

24. Monitoring X 5 d

25. Shape/size of Candidate Site X No remaining capacity. 1, 4, 7 d

26. Size of Buffer Zone X See item 1. 2, 3, 4, 7, 11 b, d

27. Potential for Cumulative Effects X No known adverse activities. 4, 7 dYaquina Bay ODMDS Environmental Assessment and MPRSA Criteria Evaluation page 15 Table 2. ODMDS Conflict Matrix for the North Site



## North Site

AREA OF

CONSIDERATION 1/CONFLICT2/POTENTIAL CONFLICTNO CONFLICTBENEFICIAL USE
COMMENTS RELEVANT
SPECIFIC
FACTORS

Eleven Specific

Factors 3/

(40 CFR 228.6) RELEVANT
SPECIFIC
FACTORS

Four General

Criteria 4/

(40 CFR 228.5)

1. Unusual Topography/Unique

Bottom Features X Gravel areas. 1, 6, 8, 11 a

2. Physical Sediment Compatibility X Similar material though ~5% is finer. 3, 4, 9 b, d

3. Chemical Sediment Compatibility X 3, 4, 7, 9 a, b, d

4. Influence of Past Disposal X Disposal from 2001-2010 has been managed under a disposal plan. A disposal plan will continue to be in place for future disposals at the site. 5, 7, 9, 10 a, b, d

5. Living Resources of Limited

Distribution X 2, 3, 6, 8, 11 a, b, d

6. Commercial Fisheries X Interference with dredge during disposal. 2, 8 a, b

7. Recreational Fisheries X Interference with dredge during disposal. 2, 8 a, b

8. Breeding/Spawning Areas X Resident and migrating fish use area. 2, 8 a, b

9. Nursery Areas X Juvenile flatfish. 2, 8 a, b

10. Feeding Areas X Resident and migrating fish use area. 2, 8 a, b

11. Migration Routes X Anadromous fish/ mammals/ flatfish. 2, 8 a, b

12. Critical Habitat of Threatened or Endangered Species X Designated critical habitat for southern green sturgeon and leatherback sea

turtle. 2, 8 a, b

13. Spatial Distribution of Benthos X 2, 8, 10 a, b

14. Marine Mammals X Feeding area/ migration route. 2, 8 a, b

15. Mineral Deposits X 1, 8 a, b

16. Navigation Hazard X 1, 8 a, b, d

17. Other uses of Ocean (cables, pipelines etc.) X 8 a, b, d

18. Degraded Areas X 4, 6, 7 a, b, d

19. Water Column Chem./Phys.

Characteristics X 4, 6, 9 a, b, d

20. Recreational Uses X See item 7. 2, 8, 11 a, b, d

21. Cultural/Historic Sites X 11 b

22. Physical Oceanography:

Waves/Circulation X 1, 3, 6, 7 a, b, d

23. Direction of Transport/Potential

for Settlement X Loss of sand from the littoral budge t. 1, 3, 6, 7 a, b, d

24. Monitoring X 5 d

25. Shape/size of Candidate Site X 1, 4, 7 d

26. Size of Buffer Zone X 2, 3, 4, 7, 11 b, d

27. Potential for Cumulative Effects X No known adverse activities. 4, 7 dYaquina Bay ODMDS Environmental Assessment and MPRSA Criteria Evaluation page 16 Table 3. ODMDS Conflict Matrix for the South Site



## South Site

AREA OF

CONSIDERATION 1/CONFLICT2/POTENTIAL CONFLICTNO CONFLICTBENEFICIAL USE

COMMENTS RELEVANT
SPECIFIC
FACTORS

Eleven Specific

Factors 3/

(40 CFR 228.6) RELEVANT
SPECIFIC
FACTORS

Four General

Criteria 4/

(40 CFR 228.5)

1. Unusual Topography/Unique

Bottom Features X Gravel areas. 1, 6, 8, 11 a

2. Physical Sediment Compatibility X Similar material though ~5% is finer. 3, 4, 9 b, d

3. Chemical Sediment Compatibility X 3, 4, 7, 9 a, b, d

4. Influence of Past Disposal X 5, 7, 9, 10 a, b, d

5. Living Resources of Limited

Distribution X 2, 3, 6, 8, 11 a, b, d

6. Commercial Fisheries X Interference with dredge during disposal. 2, 8 a, b

7. Recreational Fisheries X Interference with dredge during disposal. 2, 8 a, b

8. Breeding/Spawning Areas X Resident and migrating fish use area. 2, 8 a, b

9. Nursery Areas X Juvenile flatfish. 2, 8 a, b

10. Feeding Areas X Resident and migrating fish use area. 2, 8 a, b

11. Migration Routes X Anadromous fish/ mammals/ flatfish. 2, 8 a, b

12. Critical Habitat of Threatened or Endangered Species X Designated critical habitat for southern green sturgeon and leatherback sea

turtle. 2, 8 a, b

13. Spatial Distribution of Benthos X 2, 8, 10 a, b

14. Marine Mammals X Feeding area/ migration route. 2, 8 a, b

15. Mineral Deposits X 1, 8 a, b

16. Navigation Hazard X 1, 8 a, b, d

17. Other uses of Ocean (cables, pipelines etc.) X 8 a, b, d

18. Degraded Areas X 4, 6, 7 a, b, d

19. Water Column Chem./Phys.

Characteristics X 4, 6, 9 a, b, d

20. Recreational Uses X See item 7. 2, 8, 11 a, b, d

21. Cultural/Historic Sites X 11 b

22. Physical Oceanography:

Waves/Circulation X 1, 3, 6, 7 a, b, d

23. Direction of Transport/Potential

for Settlement X Loss of sand from the littoral budge t. 1, 3, 6, 7 a, b, d

24. Monitoring X 5 d

25. Shape/size of Candidate Site X 1, 4, 7 d

26. Size of Buffer Zone X 2, 3, 4, 7, 11 b, d

27. Potential for Cumulative Effects X No known adverse activities. 4, 7 dYaquina Bay ODMDS Environmental Assessment and MPRSA Criteria Evaluation page 17 Figure 3. Conflict Matrix Legend

1/ Definition of “Areas of Consideration” 1. Unusual Topography/Unique Bottom Features : Would placement of material in this candidate site affect physical bottom feature that is unique within the local or regional area? 2. Physical Sediment Compatibility : Does the candidate site have similar sediment characteristics to anticipated redged material? 3. Chemical Sediment Compatibility : Does the candidate site have similar chemical characteristics to anticipated dredged material? 4. Influence of Past Disposal : Would placement of material in this candidate site be affected by previous disposal of dredge material? 5. Living Resources of Limited Distribution : Would placement of material in th is candidate site affect any living

resources that do not have a coast-wide distribution?

6. Commercial Fisheries : Would placement of material in this candidate site affect any commercial fishing activity (resource impacts are covered in 8-11)?

7. Recreational Fisheries : Would placement of material in this cand idate site affect any recreational fishing activity (resource impacts are covered in 8-11)? 8. Breeding/Spawning Areas : Would placement of material in this cand idate site affect breeding and spawning areas of any species? 9. Nursery Areas : Would placement of material in this candida te site affect nursery areas of any species? 10. Feeding Areas : Would placement of material in this candida te site affect feeding areas of any species? 11. Migration Routes : Would placement of material in this candidate site affect migration routes of species?

12. Critical Habitat of Th reatened or Endangered Species : Would placement of material in this candidate site affect critical habitat of threatened or endangered species? 13. Spatial Distribution of Benthos : Would placement of material in this candidate site change the benthic invertebrate community structure, e.g., fine-g rain species to coarse-grain species, etc?

14. Marine Mammals : Would placement of material in this candidate site affect marine mammals or their habitat, e.g., gray whale feeding areas etc? 15. Mineral Deposits : Would any known mineral deposits be affected by the placement of material? 16. Navigation Hazard : Would the placement of material create a navigation hazard?

17. Other Uses of Ocean : Would placement of material impact other us es of the ocean not addressed elsewhere, such as cables, pipelines, tow boat lanes, and pilot transfer points? 18. Degraded Areas : Would disposal in this candidate site continue to affect or improve the degraded area? 19. Water Column Chemical/Physical Characteristics : Would placement of material in this candidate site affect water column chemical/physical characteristics?

20. Recreational Uses : Would placement of material affect recreational uses?

21. Cultural/Historic Sites : Would placement of material in this candidat e site impact or protect a cultural/historic

site? 22. Physical Oceanography: Waves/Circulation : Would placement of material affect wave/circulation patterns? 23. Direction of Transport/potential for Settlement : Would placement of material a ffect direction of sediment transport and/or potential for settlement? 24. Monitoring : Would use of this candidate site affect either on-going monitoring or the ability to monitor using conventional methods? Monitoring typically would include periodic hydrographic surveys, could include sediment sampling or biological data collection. 25. Shape/size of Candidate Site : Is the candidate site suitable for the operation of a dredge? Maneuverability of the dredge? Is it orientated so the dredge can place material while heading into the waves? Is the depth of water sufficient to open the hopper doors/dump scow? Can the dredge operate safely? Is the size of the candidate site large enough for long term use?

26. Size of Buffer Zone : Is the candidates site a sufficient distance from important resources or features to protect them from any affect of disposal?Yaquina Bay ODMDS Environmental Assessment and MPRSA Criteria Evaluation page 18 Figure 3 (continued). Conflict Matrix Legend

27. Potential for Cumulative Effects : Would placement of material contribu te to cumulative effects from other

activities?

2/ Definition of Degrees of Conflict

Conflict : There will definitely be an adverse impact on the resource or the use.

Potential Conflict : There is a possibility of an adverse impact; however, extent and significance are unknown.

No Conflict : There will definitely not be an advers e impact on the resource or the use.

Beneficial Use : There will be a positive impact on the resource or the use.

3/ Eleven Specific Factors for Ocean Disposal Site Selection (40 CFR 228.6) 1. Geographical position, depth of water, bottom topography, and distance from coast. 2. Location in relation to breeding, spawning, nursery, feeding or passage areas of living resources in adult or juvenile phases. 3. Location in relation to beaches or other amenity areas. 4. Types and quantities of waste proposed to be disposed and proposed methods of release, including methods of packaging the waste, if any. 5. Feasibility of surveillance and monitoring. 6. Dispersal, horizontal transport, and vertical mixing characteristics of the area, including prevailing current velocity, if any. 7. Existence and effects of present or previous discharges and dumping in th e area (including cumulative effects). 8. Interference with shipping, fishing, recreation, minera l extraction, desalination, she llfish culture, areas of special scientific importance and other legitimate uses of the ocean. 9. Existing water quality and ecology of the site, as determined by available data or by trend assessment or baseline

surveys. 10. Potential for the development or recruitment of nuisance species within the disposal site. 11. Existence at or in close proximity to the site of any significant natural or cultu ral features of historical importance.

4/ General Criteria for the Selection of Ocean Disposal Sites (40 CFR 228.5) a. The dumping of material into the ocean will be perm itted only at sites or in areas selected to minimize the interference of disposal activities with other activities in the marine environment, particularly avoiding areas of existing fisheries or shell fisheries, and region s of heavy commercial or recreational navigation. b. Locations and boundaries of disposal sites will be ch osen so that temporary perturbations in water quality or other environmental conditions during initial mixing caused by disposal operations anywhere within the site can be expected to be reduced to normal ambient seawater levels or to undetectable contaminan t concentrations or effects before reaching any beach, shoreline, marine sanctuary, or known geographically limited fishery or shell fishery. c. Effective January 9, 2009, 40 CFR Part 288.5 was amended by removing and reserving paragraph (c). d. The sizes of ocean disposal sites will be limited in or der to localize, for identification and control, any immediate adverse impacts and to permit the implementation of effective monitoring and surveillance programs to prevent adverse, long-range impacts. The size, configuration, and location of any disposal site will be determined as a part of the disposal site evaluation or designation study. e. EPA will, whenever feasible, designate ocean dumping sites beyond the edge of the continental shelf and other such sites that have been historically used.Yaquina Bay ODMDS Environmental Assessment and MPRSA Criteria Evaluation page 19 Eleven Specific Factors and Four General Criteria for Ocean Disposal Site
Selection

The determination to designate an ODMDS w ill be based on the government’s evaluation of compliance with the eleven specific factors and four general criteria at 40 CFR 228.6 and 228.5.

A discussion of each factor and criteri a for the North and South sites follow.

Application of Eleven Specifi c Criteria (40 CFR 228.6)

Geographical Position, Depth of Water, Botto m Topography and Distance from the Coast (1) . Figure 1 shows the location and bottom topogra phy of the North Site and the South Site. Designated sites would be used for disposal of dredged material from the Yaquina Bay navigation project and other permitted projects.

Site coordinates (degrees, minutes, seconds; No rth American Datum 1983) and dimensions of

North Site and the South Site are as follows:

North Site

Corner Coordinates : Dimensions : 44° 38’ 17.98” N, 124° 07’ 25.95” W 4,000-feet wide by 6,500-feet long 44° 38’ 12.86” N, 124° 06’ 31.10” W 597 acres 44° 37’ 14.33” N, 124° 07’ 37.57” W Azimuth (long axis): 10° T 44° 37’ 09.22” N, 124° 06’ 42.73” W Depth: 112-152 feet

South Site

Corner Coordinates : Dimensions : 44° 36’ 04.50” N, 124° 07’ 52.66” W 4,000-feet wide by 6,500-feet long 44° 35’ 59.39” N, 124° 06’ 57.84” W 597 acres 44° 35’ 00.85” N, 124° 08’ 04.27” W Azimuth (long axis): 10° T 44° 34’ 55.75” N, 124° 07’ 09.47” W Depth: 112-152 feet

Based upon consideration of the location, depth of water, bottom topography, and distance from the coast, the North and South Sites are suitable fo r the disposal of dredged material when placed in accordance with the Site Management and Monitoring Plan (SMMP; see Appendix F).

Location in Relation to B reeding, Spawning, Nursery, Feeding, or Passage Areas of Living Resources in Adult of Juvenile Phases (2). The North and South ODMD Sites are located approximately 2.5 miles offshore where species char acteristic of nearshor e sandy areas occur. A broad scale assessment of physical, chemical and bi ological characteristics of this area of the Pacific Ocean encompassing the Sites are desc ribed in Richardson 1973; Peterson and Miller 1977; Richardson and Pearcy 1977; Brodeur et al., 1985; Keister and Peterson 2003; Auth and Brodeur 2006; Auth et al., 2007. Marine pe lagic communities of zooplankton (copepods, euphausiids, pteropods, and chaetog naths), meroplankton (fish, cr ab and other invertebrate larvae), forage species, and pelagic predators ha ve coast-wide distributi on and generally display seasonal changes in abundance. Research c onducted to study large s cale marine ecosystem patterns along the Oregon coast and out to the shelf break indicate that these species have notYaquina Bay ODMDS Environmental Assessment and MPRSA Criteria Evaluation page 20 been shown to congregate offshore of Yaquina Ba y when compared to other river mouths on the Oregon coast.

Spawning . The disposal sites support a variety of pelagic and demersal fish species and epibenthic invertebrates includ ing Dungeness crab. Many of these species have a reproductive strategy that includes rel easing a large quantity of eggs so that some individuals will survive the substantial mortality common to the species during the larval a nd juvenile stages. Crabs in particular release large numbers of eggs into the water colum n. The larvae that hatch are planktonic for several months before settling to the bottom of the estuary as young crab. As they mature, they typically move out of the estuarie s and nearshore areas that have structure into sand-dominated, unstructured enviro nments such as those found at the North and South Sites.

Passage Areas . Coho, steelhead, and Chinook salmon that spawn in the Yaquina River watershed may pass over the disposal site area s. NMFS concluded in th eir Biological Opinion for the Corps Operations and Maintenance dr edging program that adult Oregon Coast coho salmon listed as threatened on the Endangered Sp ecies Act (ESA) are not likely be adversely affected by disposal, but some juveniles may be injured or killed. However, the number of fish injured or killed is not significant to the exis tence of the population, and hence it would not affect the viability of the species. For ESA-listed southern green sturgeon, both disposal sites and the entire ZSF is designated critical habitat because it is used as a migratory corridor by subadults and adults of this species. In NMFS’ Biological Opinion for the Corps Operation and Maintenance dredging program, they concluded th at disposal of dredge d material would not adversely modify or destroy their critical habitat.

Nursery Areas . Sandy substrate along the Oregon Coast is used as nursery areas for juvenile flatfish such as English sole, Pacific sanddab, Sp eckled sanddab, Butter sole. Juvenile flatfish are found at these sites during spring and summer.

Feeding . The disposal sites are not known to congr egate organisms because of food resources, however, the substrate does provide prey items (polychaetes, amphipods, sand dollars, gastropods, shrimp, etc) that are consumed by fl atfish, green sturgeon, cr ab, and other demersal organisms.

In summary, the Yaquina ODMD Sites encompa ss these resources however these Sites are not providing unique breeding, spawning, nursery, feedi ng, or passage habitat. The habitat for these species is not geographically limite d and the disposal of dredged material occurs for discrete periods of time over a discrete spatial area. Thus, effects to these habitat types are not likely to translate into significant effects at a population or species level.

Location in Relation to Beac hes and other Amenity Areas (3). The North and South Sites are

located to the north and to th e south of the entrance to th e mouth of Yaquina Bay. The shoreward edges of both are approximately 2 nau tical miles off the beach in 112 feet of water beyond the neritic reefs. The s eaward edge extends to 152-foot depth contour. The EPA and the Corps attempt to keep material within the l ittoral cell to the maximum extent practicable. However, for Yaquina’s ODMD Sites, this is not possible because the Yaquina reef complex runs parallel and near to the shore for the length of the ZSF. Given the reef complex’sYaquina Bay ODMDS Environmental Assessment and MPRSA Criteria Evaluation page 21 juxtaposition near shore at shallow depths, it is not operationally feasible nor safe for dredges to dispose of dredged material inshore of the reefs. Thus, the EPA and the Corps have chosen sites offshore of the Yaquina reef at de pths where sediment is not exp ected to return to the Newport

littoral cell. The loss of th is material is not expected to aff ect Newport’s beaches because Pacific Northwest beaches tend to respond strongly to storm effects, the episodic nature of which would mask any long-term discrete changes. 1

Types and Quantity of Wastes Proposed to be Disposed of, and Proposed Methods of Release, including Methods of Packing the Waste, if Any (4). Dredged material subject to the

MPRSA is not a waste. Sites that are designated will receive dredged materials transported by either government or private co ntractor hopper dredges or dump barges. Current hopper dredges or dump barges available for use have hopper ca pacities ranging from 800 to 6,000 cy. This would be the likely volume range of dredged mate rial deposited in any one dredging placement cycle. The dredged material to be removed annually from the Yaquina Bay project could be placed at the sites in one dredging season by any combination of private and government dredges. The dredges or barges would be unde r power and moving during disposal, allowing the maintenance of steerage.

The majority of the dredged material disposed in the ocean traditionally comes from shoals in the Yaquina Bay entrance channel. They consist pr imarily of marine sand transported into the entrance. The material is clean, contains no co ntaminants of concern in excess levels, is far removed from known sources of contaminants, and is acceptable for unconfined open-water disposal. Material proposed to be dredged from the turning basin (RM 2+00 to 2+25), the South Beach Marina, North Marina, and Depot Slough is finer but has been evaluated and found acceptable for unconfined open-water disposal. Fine -grained material from these areas and other side channels or backwater areas may be placed offshore in the future which will require testing

and evaluation. The sites have b een sized to accommodate the quant ity of material to be placed.

Feasibility of Surveilla nce and Monitoring (5). The feasibility of surveillance and monitoring is maximized when disposal sites are located near shore and a port where research vessels can be

launched. The closer the sites are to such faciliti es the lower the cost to monitor (lower fuel costs, less time). Thus, when consid ering feasibility, sites are chosen as close to shore as possible to meet criteria for operational capability and safe ty for dredges, and to match the grain size of the dredged material as closely as possible. Th e EPA will monitor the sele cted sites for physical, biological, and chemical attributes. The seafloor will be surveyed for bathymetry annually, the

contaminant levels in the material will be anal yzed prior to dumping, and the benthic infauna and epibenthic organisms will be monitored every 5 years, as funding allows. The Hatfield Marine

Science Center is a hub for federa l, state, and academic research ers focused on marine resources.

The EPA intends to collaborate with marine re source entities based in Newport for routine monitoring and special studies.

Dispersal, Horizontal Transport and Vertical Mi xing Characteristics of the Area Including Prevailing Current Direction and Velocity, if Any (6). Appendix B provides a detailed discussion regarding this criteri on. The North Site and South Site are located in water depth of 115 to 150 feet along the boundary between the inne r shelf and the mid-shelf. Waves and wind-

1 Personal communication. Email from J. Allen (DOGAMI) to B. Lohrman (EPA). August 22, 2011.Yaquina Bay ODMDS Environmental Assessment and MPRSA Criteria Evaluation page 22 driven currents are the most im portant factors influencing wate r motion (and potentially transport of bottom sediment) on the inner and mid-shelf. Mean circulation on the shelf tends to be along the bathymetric contours and is subject to seasonal reversal, being northward during winter and southward during summer. Mean depth-averaged current during winter is about 1.3 feet/second @ 298° (T); during summer it is 0.5 feet/second @ 202° (T). During winter storms, waves can exceed 30 feet and depth averaged currents can exceed 2 feet/second. Superimposed on the

mean circulation of the shelf are tidal currents th at are believed to account for more than half of the water motion over periods of several days . Appendix B provides additional information.

Although intense winter storms are capable of transporting sa nd at depths of 150 feet, the transport will be episodic over the long term. Consequently, sand placed at the North and South Sites will likely remain within the sites for 10 to 20 years. The directi on of net transport during significant winter storm activity wi ll be to the north and offshore. During summer, transport will

be much less but will be toward shore.

Existence and Effects of Current and Previous Discharges and Dumping in the Area (including Cumulative Effects) (7). Between 1977 and 1985, material was placed in the EPA Interim Site. Between 1986-2000, dredged material was placed in the nearshore Section 103 site selected by the Corps. Due to mounding, the nearshore Section 103 site was expanded in 1998

to include the outer two-thirds of the EPA Interim Site; material was placed in this expanded area in 1999. In 2000, a total of 79,800 cy of dredged mate rial was placed in the southwest corner of

the 1986 nearshore Section 103 site.

In 2001, the Corps, Portland District, under it s Section 103 authorit y, selected two new ODMDSs (North Site and South Site) for the di sposal of dredged material. Between 2001 and 2009, all dredged material was placed in the no rthern half of the S ection 103 North Site. Maximum mound height in 2007 reached 5 feet, wh ile in 2008 it reached 6 feet and in 2009 the maximum mound height reached 10 feet relative to July 2001. In 2009-2010, material from Depot Slough was dredged by clamshell and barged to the North Site. Also a portion of the material from the Yaquina Bay federal project was pl aced in the southern ha lf of the North Site.

Portions of the north half of the North Site have mounded 10-12 feet above the 2001 baseline bathymetry. All dredged material was placed in the southern half of the North Site during the 2011 dredging season. No material has been placed in the South Site as of the end of the 2011 dredging season.

As with other areas along the Oregon coast, m ounding of dredged material has been the most significant effect within and in the vicinity of the existing disposal si te at Yaquina Bay. The

benthic studies at the North a nd South Sites are typical for these marine sandy substrates.

Baseline studies at the Sites were conducted by the Corps in summer 1999 and 2000. The Corps carried out additional benthic sampling in 2002. In 2008, the EPA surveyed benthic infauna within and outside the disposal sites. The result s suggest that immediately after dredged material was dumped, the number of species decreased in the direct disposal areas. There was a slight decrease in the number of species per grab within the disposal ar ea when compared to outside the disposal area. Thus, prey res ources were reduced shortly afte r a disposal but not lost. The abundance or diversity of epibenthic fish did not appear affected when trawls within and outside the disposal sites were compar ed (Appendix A; pages A15-A21).Yaquina Bay ODMDS Environmental Assessment and MPRSA Criteria Evaluation page 23 Interference with Shipping, Fishing, Recreation, Mining Extraction, Desalination, Fish and Shellfish Culture, Areas of Special Scientific Importance and Other Legitimate Uses of the Ocean (8).

Shipping. The EPA does not anticipate conflicts with commercial navigati on at the North or

South Sites. The north end of th e South Site overlaps slightly with the shallow and deep draft commercial shipping lane for Yaquina Bay, however , the infrequency with which the dredge will be at the Sites (up to 38 days per year) a nd the length of time they will be disposing (approximately 5 minutes) minimizes the likelihood of a spatial conflict w ith other vessels. The potential for conflict with dredges or tug and barge combinations transiting to the Sites are recognized but can be managed through coordinati on with the boat pilots, the U.S. Coast Guard,

and others.

Commercial and Recreational Fishing. The coho and Chinook salmon fishery and recreational and commercial Dungeness crab fisheries occur at the Sites. These activitie s occur almost within the entire ZSF but vary annually in intensity be cause of shifting movement of these resources

and seasonal restrictions.

The principal recreational fishing off the coast near Yaquina Bay is for salmon and bottom fish; salmon fishing is done primarily from charter an d private boats, and a lthough it occurs in the same areas as commercial fishing, it is generally done closer to shore. Private and charter boats also conduct bottom fishing for halibut, rockfis h, and lingcod, which are generally associated with rocky areas. Other recreati onal activities in this area incl ude clamming in the bay and along the beach, and fishing off the jetties.

The potential exists for conflicts between the dr edge and fishing boats; however, this has not been a problem in the past. When the Interim a nd nearshore Section 103 site s were in use, crab

fishermen stated that the mounds created by the disposal of materi al affected th eir ability to navigate in and out of the bay sa fely, which affected the success of their fishery. Mounding is a primary concern at the historic Yaquina Bay ODM DS, thus facilitating th e need for designating new disposal sites. Bathymetric monitoring will be conducted to preven t creation of disposal mounds that would cause navigation hazards. The sh ift to using the larger North Site and South Site will provide greater site management opportunity to reduce the potential effects of mounding. Disposal at these Sites will create a permanent bathymetric change; however, greater water depths, mound height restri ction, and site monitoring will avoid interference with small and large vessel navigation.

Recreation. The Yaquina Bay vicinity offers a wide va riety of recreation o pportunities during all seasons of the year. The primary categories of activities are things like beachcombing, wildlife viewing from shore or a boat, and fishing (A ppendix E, Figure E-1). Nearby beaches and entrance jetties receive a continual influx of recr eationists. South Beach State Park is located adjacent to the Yaquina Bay south jetty and pr ovides camping and day-use facilities and beach access. Based on a survey by Surfrider, the Sites have minimal overlap with common

recreational activities offshore of Newport (Appendix E, pages E-3 to E-6). Given the discreteYaquina Bay ODMDS Environmental Assessment and MPRSA Criteria Evaluation page 24 spatial and temporal components of disposal, it is unlikely that any interference would occur

with these activities.

Mineral Extraction. There are no known mine ral extraction operations or proposed operations in the vicinity of the disposal sites. The disposal sites are not expect ed to interfere with any future offshore mining or oil/gas exploration or extraction.

Desalination. There are no desalination plants in the area of Yaquina Bay.

Fish and Shellfish Culture. There are no commercial fish or sh ellfish aquaculture operations that would be impacted by use of the North Site and South Site.

Areas of Special Scientific Importance. There are numerous oceanographic research efforts within the vicinity of the ODMDS. The Newport Hydrographi c line is likely the most consistently studied transect in Oregon. It runs east-west and is located approximately 0.83

nautical miles north of the North ODMDS. Th ere is also the Oregon, California, Washington line-transect and ecosystem (ORCAWALE) survey that runs north-south along the eastern edge (at an approximately 0.20 nautical mile distance) of the ODMDS. This survey looks at birds, cetaceans, plankton, squid, and physical paramete rs of the water column. In addition, the Northwest National Marine Renewable Energy Cent er is intending to establish a wave energy testing area anywhere between 0.92 and 3 nautical miles north of the North ODMDS. None of these on-going studies would be imp acted by disposal at the Sites.

Coastal Zone Management. The preferred action (designatio n and use of the North Site and South Site) has been determined by the US ACE and EPA to be consistent with the acknowledged local comprehensive plans and State of Oregon Coastal Zone Management Programs. The Oregon Department of Land Cons ervation and Development will review this consistency determination with a request to provide written notification of their findings.

The Existing Water Quality and Ecology of the Site as Determined by Available Data or by Trend Assessment or Baseline Survey (9). Water and sediment quality analyses conducted in the study area and experience with past disposals in this region have not identified any adverse water quality impacts from ocean disposal of dre dged material. The ecology of the offshore area is a northeast Pacific mobile sand community. Th is determination is based mainly on fisheries and benthic data. Neither the pelagic or bent hic communities should sustain long-term adverse

effects because of their resili ence to episodic disturbance and widespread distribution off the Oregon coast.

Potentiality for the Development or Recruitment of Nuisance Species in the Disposal Site (10). Nuisance species are considered as any undesi rable organism not prev iously existing at the disposal site. They are either tr ansported or recruited to the site because the disposal of dredged materials created an environment where they coul d establish. Materials dredged and transported to the disposal sites historically have been cla ssified as uncontaminated marine sands similar to

the sediment at the ODMDSs. Potential materi al dredged from the federal turning basin (RM 2+00 to RM 2+25), South Beach Marina, Depot Slough, or other in-bay area may include finegrained material. Limited quantities of fine-gra ined material from the turning basin and DepotYaquina Bay ODMDS Environmental Assessment and MPRSA Criteria Evaluation page 25 Slough have been placed in the ocean. Any materi al proposed for placement at any site would be subject to sediment quality eval uation. Therefore, it is highly unlikely that any nuisance species

could be established at the dis posal sites since habitat or contaminant levels are unlikely to change over the long term.

Existence at or in Close Proximity to the Si te of any Significant Natural or Cultural Features of Historical Importance (11). The neritic reefs off the Oregon coast comprise a unique ecological feature. They support a wide variety of inverteb rates and fish species, as well as a bull kelp community.

The cultural resource literature search conduc ted for the Yaquina Bay study area (Appendix D)

resulted in the documentation of wrecked vessels in the nearshore area. Although the majority of these shipwrecks occurred on the bar, ocean curren ts deposited some of these vessels on South Beach. In addition, other vessels were towed and then abandoned on South Beach. Given the characteristics of Yaquina Bar, onshore current pattern, hard sand bottom, and the fact that the ship channel over the bar has been actively ma intained by dredging and removal of shipwrecks from the 1860s to present, it is unlikely that any shipwrecks have survived in the vicinity. Shipwrecks within these areas would likely be torn apart due to the high-e nergy wave climate. Deeper water would buffer the high-energy wave c limate so shipwrecks in deeper water would be less prone to damage. The shipwrecks in deeper water tend to have more cultural value than shipwrecks nearshore.

Undiscovered shipwrecks could occu r in the area, however. Severa l sidescan sonar studies were conducted at the two sites. No potential shipwr ecks or other cultural feature was noted. Based on this information, it is unlikely that any significa nt cultural resources will be affected from designation and use of the disposal site.

Application of Four Genera l Criteria (40 CFR 228.5)

Minimize Interference wi th Other Activities (a.) . The first of the four general criteria requires that a determination be made as to whether the proposed sites or their use will minimize

interference with other activities in the marine environment. EPA used information from a variety of sources to determine what activities may interfere with disposal of dredged material at the Yaquina ODMDS. EPA considered recreatio nal activities (extract ive and non-extractive), commercial fishing areas, cultural or historica lly significant areas, commercial and recreational navigation, and existing scientific research activities. The information as to where these

activities occur was obtained from the Stat e of Oregon’s Ocean Information web site ( http://www.oregonocean.info/ ) that included GIS data for non-ex tractive recreational activities, commercial fishing areas, towlane agreements, exis ting scientific research areas. Information on

cultural resources was obtained fr om NOAA’s Office of Coast Survey ( http://www.nauticalcharts.noaa.gov/ ). Information on commercial and recreational finfish and

shellfish areas was also obtained from ODFW. 2 This information is provided in maps in Appendices A, D, and E. The use of this info rmation allows EPA to determine the degree to which this area is used by existing users, and how might the indirect eff ect of site designation and disposal of dredged material w ould interfere with these activities.

2 Personal communication between B. Lohrman (EPA) and M. Donnellan (ODFW), September 2011.Yaquina Bay ODMDS Environmental Assessment and MPRSA Criteria Evaluation page 26 In terms of interference with other activities, the known activities that spatially overlap with the

ODMDS include recreational activities such as boating and whale watchi ng, recreational finfish or Dungeness crab fishing, commercial finfish or Dungeness crab fishing, tow lane agreements between tow boat operations and Dungeness crab fishermen, and recreational and commercial navigation. Even though these activities may spa tially overlap, the ODMDS and the disposal of dredged material in the sites e ither do not interfere with the activities at all (whale watching, boating, navigation into or out of Yaquina Bay), or do not interfere with the activities at a level that would result in significant e ffects to the activity. An exampl e of such an activity would be commercial or recreational fishing. Disposal occurs for a finite number of days per year (up to 32 days), so any interaction between the dredge vessel and fishing vesse ls would be extremely limited. In addition, disposal occurs for approxi mately 20 minutes, so the time disposal is occurring at the site is extremely limited.

The information gathered about existing activitie s at the ODMDS has not identified any potential

conflicts that would eliminat e the sites from considerati on for final ODMDS designation.

Minimizes Changes in Water Quality (b.). The second of the four general criteria requires changes to ambient seawater quality levels occurri ng outside the disposal s ite to be within water quality criteria, and that no detectable contamin ants reach beaches, shoreline, sanctuaries, or geographically limited fisheries or shellfisheries. No significant contaminant or suspended solids releases are expected. Based on previous work atYaquina Bay, disposal of either sandy or finegrained material would not have any long-term impact on the wa ter quality. There would be no water quality perturbations to be concerned with moving toward any beach, shoreline, marine sanctuary, or known geographically limited fishery or shellfis hery. Bottom movement of deposited material generally shows a net offshore movement for the finer fractions. Coarser size fractions stay in the same general area as deposited.

Interim Sites Which Do Not Meet Criteria (c.). Effective January 9, 2009, 40 CFR Part 288.5 was amended by removing and reserving paragraph (c).

Size of Sites (d.). The fourth general criterion requires that the size, configuration and location of the site be evaluated as part of the study and that the size be limited. Ocean disposal sites are sized to localize, for identification and contro l, any immediate adverse impact and permit the implementation of effective monitoring and su rveillance programs to prevent long-ranged impacts. This in the past was interpreted to mean the absolute minimum size possible. The size of the Interim Site was based upon the minimum si ze site that a hopper dredge can operationally use. This narrow interpretation maximized the eff ects of disposal in these small sites. As a result, mounding of dredged material occurred to the point that the wave climate was altered and imperiled navigation safety, especially for small boats transiting the area. Therefore, the only management option available was to discontinue placement of mate rial in the Interim Site and

select an alternate site.

The North and South sites have been sized to provide sufficient capacity to accommodate material dredged from the Yaquina project, as we ll as material from other projects. The size of

the North and South sites was modeled based on th e requirement to provide at least 20 years ofYaquina Bay ODMDS Environmental Assessment and MPRSA Criteria Evaluation page 27 disposal capacity per site, without the sites accumulating dredged material to a height that could potentially amplify waves. Since the average wate r depth at the sites is 135 feet, dispersion of dredged material was assumed to be negligible. This required that the each site have the capacity to “store” all material pla ced without forming a mound highe r than 14 feet which led to minimum required size of 3,900 feet x 3,900 feet. Th e effective usable area for each site was set at 5,500 feet x 2,800 feet (equivalent to the mini mum required size). The addition of a 500-foot buffer zone along the perimeter of each site pr oduced the dimensions of 6,500 feet x 3,800 feet per site. Overall site dimensions were round ed up to 6,500 feet x 4,000 feet. Management of material placement in these larger, deeper sites will assure that the wave climate will not be significantly affected and naviga tional safety not compromised.

Annual bathymetric surveys of the placement ar ea will be conducted as part of the SMMP (Appendix F). The results will be used to document the fate of the dredged material and provide information for future management.

Sites Off the Continental Shelf (e.). Potential disposal areas located off the continental shelf

would be at least 20 nautical miles offshore in water depths of 600 feet or more. The haul distance to an off-shelf disposal site is much greater than the 4.5 nautical mile average operational limit of the Yaquina Bay project, maki ng an off-shelf site infeasible for maintenance of the project. Material dre dged by clamshell could be transpor ted feasibly off the continental shelf by barge. However, the cost for ev aluation and monitoring along with unanswered environmental concerns about disposal in such areas makes off-shelf disposal undesirable. Further, disposal would remove sediments from the nearshore littoral transport system, a system that functions with largely non -renewable quantities of sand in Oregon. Disruption in the mass balance of this system could alter erosion/a ccretion patterns impacting beaches, spits, wetlands,

and other shoreline habitats.

Benthic and pelagic ecosystems near the shelf cont ain important fishery re sources and the effects of disposal operations upon those resources ar e not well understood. Fine-grain sediment and rocky habitats would be directly impacted in disposal operations . These deep-water areas are stable and generally not disturbed by wave action or sedime nt movement. Consequently, these

areas have benthic invertebrate communities that are adapted to very stable conditions and would not likely be able to survive dist urbance from disposal. Little is known of the ecology of benthic communities on the continental slope, and disposal in this area could cause impacts of unknown severity and duration. Bottom gradients can be 5% to 25% on the continental slope, making accumulated unconsolidated sediments susceptibl e to slumping. Deposited sediments could be transported long distances downsl ope as turbidity currents and o ffshore by near-bottom currents.



### DETERMINATION OF COMPLIANCE AND SELECTION FOR FORMAL DESIGNATION (40 CFR 227)

Determination of Environmental Acceptability of Ocean Disposal (Subpart B) . The USACE

and EPA have documented for the record via th is evaluation the anticipated environmental effects from designation of ocean dredged material disposal s ites offshore of Yaquina Bay and from the potential future regulated use of thos e sites pursuant to the SMMP (Appendix F) for disposal of dredged materials. Designation of ocean dredged material disposal sites does notYaquina Bay ODMDS Environmental Assessment and MPRSA Criteria Evaluation page 28 mandate use; however, once designated, use of si tes is anticipated. Material that could be disposed in the ocean is anticipated to be clean gravel, sand, silt and clay from the Yaquina Bay and estuary.

By regulation, dredged sediments suitable fo r ocean dumping may not contain any materials listed in Section 227.5 or contain any of the mate rials listed in Section 227.6 except as trace

contaminants. Determination of trace cont aminants is accomplished by USACE and EPA evaluation of the dredged materi al employing the procedures of applicable national and regional testing manuals. Compliance with the applicable prohibitions, limits, and conditions for site use will assure that formal designation of ocean dredge d material disposal sites and their use will not unduly degrade of endanger the marine environment.

With respect to this subpart, it is conclude d that site designation and use would present:

a) No unacceptable adverse effects on human health and no significant damage to the resources of the marine environment; b) No unacceptable adverse effect on the marine ecosystem; c) No unacceptable adverse persistent or permanent effects due to the dumping of dredged materials; and d) No unacceptable adverse effect on the ocean for other uses as a result of direct environmental impact.

Determination of Need for De signation of Sites (Subpart C) . The need for ocean dumping has been adequately documented by a thorough eval uation of the factors listed in Section 227.15. No practicable alternatives presently exist to manage dredged sediments from the Yaquina Bay federal project. Designation of ocean dredged ma terial disposal sites to fulfill the present and anticipated future need is require d. While the use of designated si tes is anticipated, that use is not mandated by the designation. Notwithstanding compliance with the other ocean dumping criteria, ocean dumping of dredged material may not be authorized if there is no need for the dumping, and alternative means of disposal are available, as determined in accordance with Subpart C. These factors must be evaluated and documented for the record for each dumping on an individual project basis.

Impact on Esthetics, Recreational and Economic Values (Subpart D) . In itself, designation of the ODMDSs has no effect on esthetics, recrea tional or economic values . Designation of the ODMDSs does not mandate use. However, use of sites once designated is anticipated and the potential for unacceptable adverse effects results from the individual and cumulative disposals at the designated sites and management by the government.

Sites are located to minimize resource impacts and use conflicts to acceptable levels, not necessarily to avoid all conflicts. Potential imp acts of using designated sites offshore of Yaquina Bay were evaluated by USACE and EPA and ar e documented in this evaluation study. Recreational use areas and the potential effects of disposal operations on recreation are described in detail in Appendix E. The EPA’ s site designation rule will defi ne site use conditions that, in conjunction with the SMMP (Appendi x F), will limit the extent a nd severity of any impacts to acceptable levels. Also, the impact of dumpi ng on esthetic, recreationa l and economic valuesYaquina Bay ODMDS Environmental Assessment and MPRSA Criteria Evaluation page 29 must be evaluated on an individual project basis for each proposed dumping. Placement of dredged material into the sites will be managed to avoid formation of mounds that could interfere with commercial fishing activities.

The government must also consider the consequences of not authorizing dis posal sites and use of those sites, including without limitation, the imp act on esthetic, recreation and economic values with respect to the municipalities and industr ies involved. Without ocean dumping, the federal entrance channel and main navigation channe l in Yaquina Bay cannot be economically

maintained. The benefits associated with cont inued ocean commerce of the Yaquina Bay system are substantial on a regional and national scal e. While all economic values would not be completely lost, failure to maintain the naviga tion projects would necessarily result in severe economic disruption to municipa lities, industries, and indivi duals throughout the Pacific Northwest. Failure to maintain the navigation pr ojects would not be expected to directly impact

recreational uses or esthetic values defined by this subpart.

With respect to this subpart, it is concluded that designation and use of the ODMDSs would not result in unacceptable adverse effects to esthetic, recreational and economic va lues. Further, it is

concluded that in the absence of ocean dum ping, unacceptable adverse economic effects to municipalities and industries will occur throughout the interior portion of th e Pacific Northwest region and the western po rtion of the nation.

Impact on Other Uses of the Ocean (Subpart E) . This evaluation study identified and

assessed the nature and extent of existing and potential uses of th e disposal sites themselves and of any areas that reasonably may be affected by designation of s ites and their use. Temporary and long-range effects were evaluated with particular emphasis on any irreversible or

irretrievable commitment of resources that would result from use of the designated sites. Based on these evaluations, it is concluded that ther e would be no unacceptable adverse effect on other uses of the ocean as defined by this subpart.



### AFFECTED ENVIRONMENT

Physical Resources

General

The Yaquina River flows into the Pacific O cean through a jettied entrance approximately 115 miles south of the Columbia River. Although Ya quina Bay is the fourth largest estuary in Oregon, its drainage basin ranks on ly eleventh in area. The estu ary is fed mainly by the Yaquina River, which drains 253 square miles and has a relatively short lengt h of 58.8 miles from its

mouth to headwaters. From its mouth to head of high tide at RM 26, it has one major tributary (Elk Creek at RM 22.3) and about 30 smaller creeks and sloughs discharging into it. The normal flow rate has been estimated at 1,078 cubic feet per second (cfs). The basin consists of 87% forest, 4% cropland, 2% rangeland, a nd 7% other. Elevations range from sea level to 2,300 feet. Annual rainfall averages 60 inches along the coas t to 100-110 inches in the eastern portions.

Yaquina Bay is described as being moderately expos ed to waves. Tidal influences extend as far as RM 26 of the Yaquina River and several mile s up Elk Creek. The mean tide range is 5.9 feetYaquina Bay ODMDS Environmental Assessment and MPRSA Criteria Evaluation page 30 with a diurnal range of 7.9 feet and an extreme range of 11.5 feet. Tidal prism on mean range is

8.35 x 10 cubic feet with a diurna l range of 11.5 x 10 cubic feet. Currents off Newport are quite variable and reportedly exhibit th e characteristics of a large eddy.

Yaquina Bay Sediments

The USACE conducted physical and chemical anal yses of sediment samples from Yaquina Bay and South Beach marina in 1980, 1986, 1990, 1991, 1995, 2000, 2005, and 2010. Potential

sources of contaminants to the federal navi gation channel are logging, wood processing, fish processing and urban runoff. From the USACE sediment sampling studies, the sediment is typically below screening levels (if they were identified at that time) for contaminants of concern. Consequently, sediment has been acceptable for in-wat er ocean disposal.

The federally authorized entrance reach extends from RM -1 to RM 4.4. Up to 370,000 cy of material is dredged from this reach annually. Material dredged from th e entrance channel is approximately 94% sand. The South Beach Ma rina access channel is approximately 2,035-feet long and runs from Yaquina RM 1 to the marina. Up to 25,000 cy of material is dredged from the access channel every 5 to 8 years. Material dredged from the South Beach Marina access channel is approximately 45% sand. The authori zed federal navigation channel is approximately 10 miles long and extends from RM 4 to 14, including Depot Slough; however only Depot Slough is maintained. Up to 100,000 cy of materi al is dredged from Depot Slough every 5 to 8 years. Material dredged from Depot Slough is predominantly silt/clay (up to 95%) with little sand (5%). Sediment evaluation reports, including sample loca tions, grain size, elutriate and bulk sediment test results are included in Appendix C.

ODMDS Sediments

The topography of the seabed in th e vicinity of the North and S outh ODMDS is fairly uniform. Depths at the sites range from 115 to 155 feet. The most recent study of sediment quality in support of EPA and USACE site designation at Yaquina was conducted in June and August 2008 by the EPA. The sampling stations were select ed based on the previous sampling efforts in 1999, 2000, and 2002 (USACE and EPA 2011). Sedi ment collected from 18 samples was primarily medium sand and showed little va riation, ranging from 97.8% to 99.7% sand-sized grains (“percent sand”) at stations in the North ODMDS drop zone and from 96.6% to 99.5% sand at the background stations. Th e mean grain size, calculated us ing percentage of grain size, was essentially the same at the North ODMDS drop zone stations (98.6%) as that of the background stations (98.3%). The mean grain si zes at the North ODMDS drop zone stations ranged from 0.195 millimeters (mm) to 0.213 mm, wh ile those at the background stations ranged from 0.171 mm to 0.308 mm. The largest grain size (0.308 mm) was collected at the deepest

location near the North ODMDS.

Sandy sediments such as these are common along the Oregon Coast with natural variation in percent fines occurring at differe nt stations depending upon variations in local current patterns.

The 1999 data showed a similar sand environment out to a depth of 160 feet off Yaquina Bay.

Material finer than silt constitutes less than 2.3%. Volatile solids are less than 1.3%. The material at the ODMDS is very similar to that collected at the historic ODMDS sites. While fine-grained sediments placed at the disposal si te would be carried in suspension and quicklyYaquina Bay ODMDS Environmental Assessment and MPRSA Criteria Evaluation page 31 removed from the site by longshore and offshore cu rrents, the coarser sediments would remain at the site for longer periods. The zone of active sediment movement in the area extends to a depth

of about -150 feet. The thinness of the sedime nt layer indicates that there is no long-term accumulation of sediment offshore from Yaquina Bay.

Oceanographic Circulation

Circulation of coastal waters on the continenta l shelf (near Yaquina Ba y) results from an interaction of regional oceanic circulation, as tronomical tides, local wind-generated surface waves and current, swell, and Ya quina River flow as affected by inland meteorological events. Time scales for coastal circulation processes range from seconds for wind generated waves to months for seasonal weather patterns to years fo r large-scale events such as El Nino and La

Nina.

A generalized model for the seasonal changes in the along shore and offshore circulation along the Pacific coast of Oregon has been developed. The summer circulation of surface water on the continental shelf is influenced by the southw ard flowing California current, which attainsmaximum strength during the summer when surface winds are consistently from the northnorthwest. Winter circulation of shelf waters is dominated by the northward flowing Davidson current, which attains maximum strength due to winter storm (wind stress) patterns. The subsurface part of the Davidson current (below 300 f eet in depth) is believed to flow northward throughout the year, although the surface waters respond to seasonally varying wind stress patterns (reversals). Therefore, the net dir ection of bottom currents on the mid- and outer continental shelf (120 to 600 feet in depth) is believed to be northward and along shore.

The time-varying circulation of coastal waters co ntrols the transport and seasonal distribution of bottom sediments and suspended material within the water column. Circulation that is consistent through time (flow through the Yaquina Bay jettie s) tends to produce iden tifiable and relatively constant bathymetry features. Circulation that is highly variable (typi cally, flow along the open coast) tends to produce homogenous ba thymetry having ephemeral features.

Inner Continental Shelf. The most active region along the co ntinental shelf is the inner shelf (depth less than 120 feet), over which shoaling wind waves and swell, shelf-modified tidal currents, and estuarine-induced currents are at least as important as wind-driven currents for promoting the transport of bottom sediments. These variable processes act on ebb tidal shoal sediments at Yaquina Bay (depths less than 120 feet) to produce th e bathymetric condition observed at any particular time. Circulation of coastal (inner shel f) waters is subject to seasonal reversal, generally being north ward during winter and sout hward during summer. Bottom currents along the inner-shelf often reach speed s high enough to transport sand-sized sediment.

Middle and Outer Shelf . Circulation along the middle shelf (120 to 300 feet in depth) is governed mainly by wind-driven cu rrents. Circulation along the outer shelf (300 to 600 feet in depth) is affected by shoaling in ternal waves and seasonally modi fied regional currents. Bottom currents along the middle and outer shelf genera lly do not reach speeds high enough to transport sand-sized sediment, but are capable of transporting fine-grain se diments (silt-size and smaller).Yaquina Bay ODMDS Environmental Assessment and MPRSA Criteria Evaluation page 32 Geology

The coastal area of Oregon has been influenced by a combination of tectonic forces and glacial effects during the past few million years. Regional uplift, coupled with a fluctuating sea level, is evidenced by marine terraces up to 100 feet above present sea level. Beneath deposits of recent sands are rocks up to 40 million years old. At th e maximum extent of the continental glaciers sea level was as much as 400 feet below presen t. Delta-like features formed from massive amounts of sediments, estimated up to 10 times pr esent volumes. The la st episode of glacial retreat began less than 20,000 y ears ago with sea level risi ng rapidly until 5,000 to 6,000 years ago. Filling the valley bottoms and the estuary are modern river sediments. These grade into marine sands near the river mouth, which cont inue offshore. Extensive coastal dunes and beaches have been formed in modern times by wind forces acting upon river/marine sands.

A succession of siltstones, mudstones, and sandstones dip seaward from 10 ° to 20 ° . A layer of

basalt intrudes the sandstone layer and forms Yaquina Head a nd the offshore reefs. In the Newport area, marine terrace deposits over 50 feet thick overlie the much older eroded

sandstones and mudstones. These terrace deposits form the steep se a cliffs north from the jetties

but are absent for 1.5 miles to the south where m odern sands form the South Beach area. Little, if any, sand is presently escaping from the estuary.

Biological Resources

Introduction

This section summarizes biological conditions in the ocean environment offshore of Yaquina Bay. Additional information is provided in Appendix A.

Plankton and Fish Larvae

Peterson and Miller (1976) a nd Peterson and others (1979) sampled the zooplankton community off Yaquina Bay and found copepods to be the dominant taxa. The species of copepods present varied with season. Of the 58 species collect ed, 8 occurred commonly in both summer and winter, 7 occurred only or predominantly in th e summer, and 6 only or predominately in the winter. In general, winter species are less abundant than summer species.

Fish larvae are a transient member of the insh ore coastal plankton comm unity. Their abundance and distribution has been described by Richar dson (1973), Richardson and Pearcy (1977), and Richardson and others (1980).

Keister and Peterson (2003) pr ovided a discussion of the z ooplankton community found off the central Oregon coast in the New port coastal area (along the New port hydrographic line). Keister and Peterson (2003) indicate that the zooplankton community is influenced strongly by seasonal variations in wind and current patterns. Accord ing to Peterson and Miller (1977), boreal neritic copepods such as Pseudocalanus mimus

, Calanus marshallae

, Centropages abdominalis

, Acartia longiremis , and Acartia hudsonica dominate the coastal plankton dur ing summer. In winter, the coastal zooplankton is populated by warm-water species such as Mesocalanus tenuicornis

,Yaquina Bay ODMDS Environmental Assessment and MPRSA Criteria Evaluation page 33 Paracalanus parvus

, Ctenocalanus vanus

, Clausocalanus spp.

, Acartia tonsa , and Corycaeus anglicus.

Auth and Brodeur (2006) examined ichthyoplankt on off the central Oregon coast (along the Newport hydrographic line). The dominant taxa collected were northern anchovy ( Engraulis

mordax ), slender sole ( Lyopsetta exilis ), rockfishes ( Sebastes spp

. ), northern lampfish ( Stenobrachius leucopsarus ), and blue lanternfish ( Tarletonbeania crenularis ). Relatively few larvae were found at depths greater than 100 meters (~328 feet), while highest larval concentrations generally were observed from depths of 0 to 50 meters (0 to ~164 feet). Larval diversity and concentration were higher offshore at 46-84 kilometers (~28.5 to 52 miles) off the

coast than in nearshore areas at 9-28 kilomete rs (~5.6 to 17 miles) off the coast. Highest concentrations were normally f ound at an intermediate station, approximately 65 kilometers (~40 miles) off the coast. Species designated as eith er coastal or offshore species by previous studies were predominantly found in their respective shel f regions. Most larval concentrations were positively correlated with temperature and negatively correlated with salinity.

Benthic Invertebrates

Early Benthic Studies . Benthic invertebrate studies were conducted offshore of Yaquina Bay in 1984, 1986, 1989, 1999, and 2000. The invertebrate fauna collected during these early studies was typical of the nearshore, high-energy environment found along th e Oregon coast. It also was

similar to the communities found near other di sposal sites along the Oregon coast. The community was dominated by highly mobile orga nisms that are adapted to a shifting sand environment. Dominant speci es and groups included gammaridean amphipods, sand dollars, surface-dwelling gastropods and various species of polychaete worms. These organisms provide

a direct food source for other bent hic organisms and demersal fishes , and also play an active role in the breakdown of organic debris, which reintroduces it back into the system.

Dominant molluscs in the early stud ies were the carnivorous gastropod Olivella spp. Three species of Olivella occur along the Oregon coast, two of which, O. biplicata and O.pycna, were collected off Yaquina Bay. Both species were present in significan t numbers during 1984, 1986 and 1989 studies. In 1999, O. biplicata was not present, but the 1999 samples were taken in deeper water and O. biplicata is a shallow-water species, while O. pycna is more abundant in water depths from 30-150 feet. Dominant sp ecies of gammaridean amphipods in the early

studies included Mandibulophoxus gilesi, Synchelidium shoemakeri, and Psarnrnonyx longimerius. These amphipods are scavengers and feed primarily on particles of organic debris

found in the sediment.

Current Benthic Studies . The most recent study of benthic infa una at and near the ocean disposal sites was conducted in June and August 2008 by EPA (USACE and EPA 2011). Appendix A provides detailed information on this study. The dominant speci es in the June 2008 data set included the polychaetes Chaetozone nr . setosa

, Magelona sacculata

, Nephtys caecoides, Onuphis iridescens

, Spio filicornis, and Spiophanes bombyx ; the crustaceans Anchicolurus

occidentalis and Eohaustorius estuarius ; and the miscellaneous phylum nemertinea. The number of polychaetes, specifically Spiophanes bombyx at a count of 3,313, far exceeded the number of other individual organisms. There were a tota l of 106 taxa of which 46 were polychaetes, 18Yaquina Bay ODMDS Environmental Assessment and MPRSA Criteria Evaluation page 34 were mollusca, 34 were crustacea, 3 were echin oderms, and 5 were miscellaneous groups. No Dungeness crab larvae or juveniles were collected.

The August 2008 survey data show a high-energy benthic community structure. The dominant species included the polychaetes Magelona sacculata, Spio filicornis and Spiophanes bombyx ; the mollusca Siliqua sp. juvenile (razor clam); the crustacea Anchicolurus occidentalis, Diastylopsis dawsoni and Photis sp. indeterminate; and the miscellaneous phylum nemertinea. As in June, the count of Spiophanes bombyx exceeded the number of other individual organisms.

There were a total of 98 taxa of which 45 were polychaetes, 20 were mollusca, 29 were crustacea, 2 were echinoderms, and 2 were mis cellaneous groups. There were four Dungeness crab larvae or juveniles collected.

The species collected in the 2008 st udy are what would be expected and are very comparable to

earlier and current studies of ODMDS areas along the Oregon co ast. The benthic infauna found were typical of the sand dwelling communities f ound along the Oregon coast, and are well suited to survival in this dynamic environment by either being very mobile or being able to respond to both man made or natural perturba tions. Either strategy allows re -colonization of disturbed areas such as dredging scars or disposal site events.

Fish and Epibenthic Species

Appendix A provides detailed information concerni ng the fish and epibenthic resources offshore of Yaquina Bay. The nearshore ar ea supports a variety of pelagic and demersal fish species and epibenthic invertebrate species. The habitat at the ocean disposal sites is not a rare or especially unique habitat for the Oregon coast, consisting of a primarily sand bottom with only a few gravel patches. Pelagic fish species include anad romous salmonids such as coho salmon, winter steelhead, and spring and fall Chin ook salmon. Other pelagic species include the Pacific herring, northern anchovy, and surf smelt.

Demersal fish species in the nearshore area are mostly residents and include a number of sculpins, sea perch, and rockfish species associated rocky habitats , as well as flatfish species occurring predominantly over open sand flats. Flatfish include Englis h sole, Pacific sanddab, and starry flounder. English sole and starry flounder and sand sole spawn in the inshore area in the summer and juveniles of thes e, as well as other marine species, may rear in Yaquina Bay.

The neritic reefs off Yaquina Bay are a unique feature of the coas t and are associated with bull kelp beds. These beds provide important invert ebrate and fish habitat and increase the overall productivity of the reef.

The commercially and recreationally important epibenthic invertebrate species in the Yaquina Bay nearshore area include shellfish and Dungeness crab. Razor clam beds are located north and south of the jetties along the beac h. Recruitment to the inshore b eaches comes from the subtidal spawning areas. Gaper clams are present in large numbers near the mouth and upriver in the estuary proper. Cockles are also present in the in tertidal areas near the base of the jetties. Piddock clams occur in the sandstone outcroppings north of the estuary mouth. Dungeness crab

adults occur on sandflat ha bitat along the entire Oregon coast. They spawn in offshore areas andYaquina Bay ODMDS Environmental Assessment and MPRSA Criteria Evaluation page 35 occur in the estuary when conditions are favorable in late summer and fall. There are currently no known squid spawning areas offshore of Yaquina Bay.

Field surveys were conducted in August 2008 by EPA to provide current information about the fish and epibenthic species present in the ar ea of the Yaquina ODMDS (USACE and EPA 2011). From all trawls, a total of 919 epibenthic fish typical of the Oregon coas t were identified. The top five species caught were but ter sole, English sole, Pacifi c sanddab, Pacific tomcod, and sand sole. Overall, the area north of the North ODMDS appeared to have a higher productivity than either the North or South ODMDS; it had the greates t number of individual fish collected during each trawl and the most fish species identified. Epibenthic invertebrates collected also showed a variety of species typical of the Oregon coast, with only Dungeness crab and short-spined pink

star collected in all trawls. These data support that the area north of the North ODMDS is a more productive area, at least locally.

Commercial and Recreational Fisheries Economics

Based on data from the National Marine Fisher ies Service (NMFS 2006) fo r commercial fishing, a total of 393 vessels, all commercially register ed, delivered landings to Newport in 2000. Landings were in the following West Coast fisher ies (data shown represents landings in metric tons/value of said landings/number of vessels making landings; NA = not available): coastal pelagic (158/$14,203/17), crab ( 1,613/$7,474,302/99), groundfish (40,389/$9,382,966/179), highly migratory species (1,403/$2,626,906/ 180), salmon (368/$1,361,844/181), shellfish (NA/NA/2), shrimp (3,628/$3,240,124/38), and ot her species (50/$222,093/106). Newport
residents owned 90 vessels in 2000; in To ledo, community members owned 20 vessels.

For Newport, the 2000 recreational salmoni d catch was 1,141 Chinook salmon and 9,124 coho

salmon. The recreational non-salmonid catch wa s a total of 125,112 fish. The top species landed included black rockfish, bl ue rockfish, lingcod, Albacore t una, Pacific halibut, chilipepper rockfish, California halibut, kelp greenling, yelloweye rockfish, a nd yellowtail rockfish.

Wildlife

Three species of seals and sea li ons inhabit the Yaquina Bay coas tal area. Steller sea lions, a federally threatened species, a nd harbor seals are year-round reside nts, while California sea lions are present most of the year. Steller sea lions forage at rive r mouths and nearshore areas along the Oregon coast. The closest Steller sea lion haul out site is located a bout 7 miles south of the Yaquina North Jetty (Seal Rock). Harbor seals br eed in the estuary and on nearshore rocks. The Yaquina Bay nearshore area and sh oreline provides habitat for s horebirds, waterfowl, herons, bald eagles, hawks, and many other species of birds. Pelagic birds (e.g., murres, auklets, cormorants) likely use Yaquina Bay and River, as well as adjacent waters for foraging.

Threatened or Endangered Species

There are 25 threatened or endangered species pr otected under the Endangered Species Act that may occur in the Yaquina Bay nearshore area. Appendix A provides detailed information concerning these species and their li kelihood of occurren ce in the area.Yaquina Bay ODMDS Environmental Assessment and MPRSA Criteria Evaluation page 36 Salmonids . The threatened listing for Oregon Coast coho salmon includes a ll naturally spawned populations in Oregon coastal streams south of th e Columbia River and north of Cape Blanco, including the Cow Creek coho hatchery program (73 Federal Register (FR) 7816). Critical habitat also was designated. Yaquina Bay and Rive r were designated as critical habitat but ocean waters were not included. Coho salmon are presen t in the Yaquina offshore area as both adults and juveniles. Adults hold in th e offshore area prior to entering the estuary to migrate up river to spawn. Juveniles rear in the nearshore ocean area after migrating downstream and transitioning to saltwater. Upstream migration of adult coho salmon ranges from August through November. Juvenile outmigration extends from Ap ril through June and peaks in May.

The threatened listing for Lower Columbia Ri ver coho salmon includes all naturally spawned populations in the Columbia Rive r and its tributaries in Washi ngton and Oregon, from the mouth of the Columbia up to and including the Big White Salmon and Hood Rivers, and includes the Willamette River to Willamette Falls, Oregon, as well as 25 hatchery programs (70 FR 37160). While migrating individuals may utilize the coastal habitat off Yaquina Bay for migratory purposes, they are likely to be further offshore than the ODMDS.

Several listed Chinook salmon (70 FR 37160) coul d potentially be in the ocean area off of Yaquina Bay. These include the Lower Columbia River (threatened), Upper Willamette River spring-run (threatened), Upper Columbia River spring-run (endangered), Snake River spring/summer run (threatened), and Snake River fa ll-run (threatened). A ll of these ESUs have designated critical habitat, but critical habitat does not include ocean waters. During their ocean life history residence period, these speci es have been found off Yaquina Bay.

Eulachon . Southern DPS Pacific eulachon is listed as threatened (75 FR 13012). Eulachon are a small, anadromous fish from the eastern Pacific Ocean. They occur in nearshore ocean waters and to 1,000 feet (300 meters) in depth, except for the brief spawning runs in to their natal (birth) streams. Most eulachon origin ate in the Columbia Basin but eulachon has been documented in the Rogue and Umpqua rivers in Oregon. Although eulachon migrate along th e coast, little is

known about their use of nearshore and marine ha bitat. In January 2011, critical habitat was proposed (76 FR 515) and did not include any ocean waters.

According to NMFS analysis supporting their lis ting, the most significant threat to eulachon and their habitats are changes in ocean conditions due to climate change (75 FR 13018). Impacts associated with dredged material disposal were not identified as a threat . Even though eulachon are found in nearshore waters, the potential for eulachon to be in the area during disposal is low because: (1) eulachon are not known to use Yaqui na Bay; thus, large numbers of returning outmigrants or adults are unlikel y to be transiting through the ODMDS areas; and (2) disposal actions occur for a limited number of days per ye ar, which limits the likelihood of fish coming in contact with dredged material disposal.

Green Sturgeon . The Southern Distinct Population Se gment (DPS) of green sturgeon was listed as threatened in 2006 (71 FR 17757) and critical habitat was designated in 2009 (74 FR 52300). According to NMFS analysis suppo rting the listing of the Southern DPS of green sturgeon, “The principal factor for decline of the Southern DPS is the reduction of the sp awning area to a limited area of the Sacramento River” (71 FR 17762). The nearest spawning habitat is in theYaquina Bay ODMDS Environmental Assessment and MPRSA Criteria Evaluation page 37 Sacramento River. Southern DPS green sturge on likely occur at the Yaquina ODMDS as they migrate north and south to access estuaries durin g summer and early fall. Designated critical

habitat includes all U.S. coastal marine waters out to the 60 fathom depth bathymetry line from Monterey Bay, California north and east to incl ude waters in the Strait of Juan de Fuca, Washington, which encompasses the ODMDS and a ll tidally influenced areas of Yaquina Bay up to the elevation of mean higher high water.

Marine Mammals and Sea Turtles . There are many whale and s ea turtle species in Oregon’s offshore coastal area that are federally listed. Th e blue, fin, sei, sperm, humpback, and southern

resident killer whales are all federally endangered species and o ccur as migrants off the Oregon coast in waters typically farther from shore than within the Yaquina ODMDS. The loggerhead, green, leatherback, and oliv e ridley sea turtles are federally lis ted and have been recorded from strandings along the Oregon and Washington coasts. The occurre nce of sea turtles off the Oregon coast is associated with the appearance of albacore and jellyfish. Albacore occurrence is strongly associated with the warm waters of the Japanese current. Because these warm waters generally occur 30 to 60+ miles offshore, these s ea turtle species do not typically occur in the nearshore area. However, NMFS designated critical habitat for the leatherback sea turtle off the coast of Oregon, which includes the North and South ODMDS.

Birds . Federally listed marine birds that may be present in the Yaquina offshore area include

marbled murrelet and short-tailed albatross. Threatened marbled murrelets are observed in small

flocks or as individuals in th e ocean throughout the year. The endangered short-tailed albatross may forage in open ocean areas off the coast. The Pacific coast popula tion of western snowy plover is a threatened species th at breeds in coastal areas in Ca lifornia, Oregon and Washington. Western snowy plover breeding and feeding occur on beaches rather than in open water.

Socio-Economic Resources

The City of Newport is located on the central Oregon coast at the mouth of the Yaquina River and is the county seat of Lincoln County. The City of Toledo is located on the Yaquina River

about 7 miles inland from the Pacific Ocean. The 2010 Census reports that Newport had a population of 9,989 people and 4.8% population growth (2000 to 2010), while Toledo had a population of 3,465 people and - 0.2% population growth. Acco rding to the September 2011 Local Labor Trends newsletter, publish ed by the Oregon Employment Department ( http://www.qualityinfo.org ), the major employers in Lincoln County include leisure and hospitality, retail trade, educational and hea lth services, manufacturing, and government. The unemployment rate in Lincoln County was 10% in July 2011.

Cultural Resources

Appendix D provides detailed information con cerning cultural resources offshore of Yaquina Bay. Prehistoric cultural resour ces are unlikely to be found within the Yaquina offshore area. It is possible that prehistoric Native Americans may have used portions of the offshore reefs as a fishery. Any remaining remnants of prehistoric fi shing activity are unlikely or not retrievable. Shipwrecks are the most probable cultural resources expected to exist in the offshore area.

Historical review indicates se veral recorded wrecks and all known shipwreck remnants are located in the South Beach area. It also is pos sible that unrecorded wrecks exist elsewhere in theYaquina Bay ODMDS Environmental Assessment and MPRSA Criteria Evaluation page 38 area. In July 2000, a side-scan sonar survey wa s conducted over a large area in and around the Yaquina North and South ODMDS. No shipwrecks or other historic remn ants were detected. Based on this information, it is unlikely that any significant cultural resources would be affected by designation of the North and South ODMDS.

Recreational Uses

Recreational resources in the area of the North and South ODMDS are described in Appendix E. Yaquina Bay area offers a wide variety of recrea tion opportunities during all seasons of the year. The primary activities include sightseeing, fishing, beachcombing and boating. Nearby beaches and entrance jetties rece ive a continual influx of recreationi sts. South Beach State Park is located adjacent to the Yaquina Bay south jetty and provides camping and day-use facilities and beach access. Yaquina Bay and the nearshore ar ea are heavily used by recreational anglers and boaters. Clamming is also a popular recreation activity. The princi pal recreational fishing is for salmon and bottom fish. Salmon fishing is done by charter boat and private boat. Bottom fishing is done along the south reef area by char ter boat for black rockfish and lingcod. The north reef is not fished to any extent becau se of its hazardous navigation conditions. Other

recreational activities include clamming in the bay and along th e beach, and spear fishing along the jetties.

Commercial Uses

The Yaquina Bay offshore area supports a mode rate commercial fishery primarily for salmon, groundfish, and Dungeness crabs. Clams are commerc ially harvested in the estuary. The fishing and tourist industries are a primary source of income to the local economy. No significant mineral or petroleum deposits are known to exist in the vicinity of the North and South ODMDS.



### ENVIRONMENTAL EFFECTS

Physical Resources

Sand deposited at the site most likely will disp erse somewhat between an nual dredging events. Sediment transport would include movement predom inately to the northwest in the winter with some southerly movement either onshore or offshore in the summer. A 500-foot “setback zone” should be inscribed within the sites to keep ma terial within the ODMDS during dredged material placement. Dispersal would occur at a lower rate overall at the sites since they are deeper than the existing sites.

Placement of material at the site will be managed to avoid creation of single conical mound features. Based on sediment fate modeling (Appendix B) th e seabed at the ODMDSs would likely experience various degrees of accumulation. On a per dump basis, the seafloor at the sites could be subjected to individual burial events ranging from 0.01 to 0.3 feet thick coveri ng an area of 5-20 acres. On a seasonal basis, the sites may be subjected to accumul ations ranging from 1-10 feet thick covering an

area of 100-500 acres. Total bot tom accumulation would be limited to a maximum of generating wave height increases of 10% or less over ex isting conditions based upon model predictions.Yaquina Bay ODMDS Environmental Assessment and MPRSA Criteria Evaluation page 39 Sediment characteristics would be modified from finer-grained botto m sediments to coarser-grained

over much of the site for a short time following disposal. Prevailing conditions will redeposit finergrained sediments within an estimated 6 months base d on monitoring data for ocean disposal sites at similar depth off the mouth of th e Columbia River (Siip ola et al. 1993). Chemical analysis of sediments likely to be placed at the disposal site s indicate contaminants are well below levels of concern for in-water placement.

No significant contaminant or suspended solids re leases are expected from use of the ODMDS. Based on previous work at Yaquina Bay, disposal of either sandy or fine-grained material would not have any long-term impact on the wate r quality. There woul d be no water quality perturbations to be concerned with moving toward any beach, s horeline, marine sanctuary, or known geographically limited fishery or shellfis hery. Bottom movement of deposited material generally shows a net offshore movement for the fi ner fractions. Coarser size fractions stay in the same general area as deposited.

Biological Resources

The most recent study of benthic infauna (USA CE and EPA 2011) show a benthic community dominated by highly mobile organisms that ar e adapted to a shifting sand environments or periodic anthropogenic disturbances . A difference in the number of species and density of

individuals between the North ODM DS drop zone (disposal has occurred) and areas outside of the drop zone (no disposal) was found. This indi cates an effect from disposal of dredged material at the drop zone. The eff ect appears to be localized to the dredge disposal site itself, and likely does not persist for greater than a few m onths given the high repr oductive rates of the majority of the benthic infauna encountered. It is not likely the e ffects on benthic infauna translate into an adverse effect on prey res ources for benthic feeding fish or epibenthic

invertebrates because of the discre te area of effect and likely s hort duration of effect (months).

In general, the locations of the Yaquina ODMDS do not provide unique breeding, spawning, nursery, feeding, or passage habitat. It is unlikely that any of th e larger organisms (fish, marine mammals, etc.) would experience physiological eff ects as a consequence of disposal because the resulting turbidity plume and physical disturbanc e to the water column would likely cause them to avoid the area. Based on modeling complete d by USACE, water column turbidity would be expected to dissipate within a few minutes to half hour. A ny avoidance behavior would be limited to the duration of this physical disturbanc e. Indirect impacts could occur if disposal operations changed the value of the habitat by burying the existing be nthic community where dredged material is deposited. The benthic community would be e xpected to re-colonize within a period of a few weeks to months after disposal, limiting any effects to fo rage fish. In addition, evaluation of past disposal activ ities has not indicated that an y long-term adverse impacts to living resources have occurred.

Disposal at the sites will result in the mortality of benthic organisms and some crabs and fish that are in the disposal location. From the 2008 bent hic and epibenthic studi es, all of the species collected were typical of nearshore, sand-dominat ed seafloor habitat. The effect to benthic invertebrates is localized to the disposal area and the effect is likely limited in duration, with full recovery expected prior to the following year’s disposal events. Any further effect up the food chain, limited prey resources, is unlikely a limiting factor for species growth or reproduction.Yaquina Bay ODMDS Environmental Assessment and MPRSA Criteria Evaluation page 40 EPA prepared a Biological Assessment (BA) to a ssess the potential effect s of designating the Yaquina North and South ODMDS on the 25 ESA-lis ted species that may occur in the Yaquina

nearshore area and submitted the BA to the NMFS and U.S. Fish and Wildlife Service. While site designation would not have a direct imp act on any ESA-listed species, there would be indirect impacts associated with reasonably foreseeable future disposal activities. These indirect impacts include a short-term increase in suspende d solids and turbidity in the water column when dredged material was disposed at the ODMDS, impacts to organi sms in the water column during disposal, and an accumulation of material on the ocean floor. EPA concl uded that its action may affect, but is not likely to a dversely affect 18 ESA-listed speci es but would likely adversely affect Oregon Coast coho salmon. In addition, EPA concluded that the indirect effects of the designation of these Sites would not adversely affect designated critical habitat for southern
green sturgeon.

Socio-Economic Resources

Designation and use of the ODMDS would not result in unacceptable adverse effects to recreational, commercial fishing, and economic values. The sites are located to minimize resource impacts and use conflicts to acceptable le vels. Placement of dredged material into the sites will be managed to avoid formation of mounds that could interfere w ith commercial fishing activities. Further, in the absence of ocean dumping, the Yaquina federal channels cannot be economically maintained. The benefits associ ated with continued ocean commerce of the Yaquina Bay system are substantial on a regional a nd national scale. While all economic values would not be completely lost, failure to mainta in the navigation project would necessarily result in severe economic disruption to municipalitie s, industries, and i ndividuals throughout the Pacific Northwest. Failure to maintain the naviga tion projects would not be expected to directly impact recreational uses or esthetic values defined.

The cultural resource literature search conducte d (see Appendix D) resu lted in documentation of

wrecked vessels in the nearshore area. Although most of these sh ipwrecks occurred on the bar, ocean currents deposited some of these vessels on South Beach. In addition, other vessels were

towed and then abandoned on South Beach. Given the characteristics of the bar, onshore current pattern, hard sand bottom, and the fact that the navigation channe l over the bar has been actively maintained by dredging, it is unlik ely that any shipwrecks have surv ived. Several sidescan sonar studies were conducted in the vicinity of the North and South ODMDS. No potential shipwrecks or other cultural features were noted. Thus, it is unlikely that any signifi cant cultural resources will be affected from designation and use of the North and South ODMDS.



### SUMMARY OF COORDINATION

Federal Action

The federal action consists of designation of two ODMDS at Yaquina Bay. Site designation does not create or confer rights on any person to use a designated site upon the effective date of site designation. Persons or entiti es who seek to use a site must first obtain a federal permit, or in the case of the USACE, meet the substantiv e permit requirements, in order to actually use a designated ocean dredged material disposal s ite. This process would include meeting theYaquina Bay ODMDS Environmental Assessment and MPRSA Criteria Evaluation page 41 requirements of applicable statutes and regula tions. The EPA recognizes, however, that site designation is intended to have a practical result. When sites ar e designated, it is expected that such sites will be used by persons or entities meeting the statutory and regulatory criteria for ocean disposal of dredged material. Therefore, actual disposal is an indirect effect of site designation and is included in the evaluation of effects unde r the below listed statutes.

Endangered Species Act

The EPA initiated consultation under Section 7 of the Endangered Sp ecies Act of 1973, as amended (16 United States Code (U.S.C.) Sec tions 1531 to 1544) with the U.S. Fish and Wildlife Service and National Marine Fisheries Service. For marbled murrelet ( Brachyramphus

marmoratus ) and short-sailed albatross ( Phoebastria albatus ) under the USFWS jurisdiction, the

EPA concluded that the indirect effects of EPA’s proposed site de signation may affect, but is not likely to adversely affect these ESA-listed species. The USFWS concurred on the EPA’s finding for endangered or threatened species under the jurisdiction of the USFWS.

The NMFS issued a Biological Opinion on July 10, 2012. The NMFS considered disposal by the

USACE and all other entities as an interrelated action to the EPA’s proposed site designation, thus, the effects from future disposals are in direct effects of the EPA’s action. The NMFS concluded that the EPA’s action is not likely to jeopardize the continued existence of Oregon Coast coho salmon, southern distinct populati on segment (DPS) of North American green sturgeon, southern DPS of Pacific eulachon, or re sult in the destruction or adverse modification of designated critical habitat fo r southern DPS North American green sturgeon. The NMFS also concluded that the EPA’s proposed action is not lik ely to adversely affect 18 ESA-listed salmon, sea lions, whales, marine turtles, and critical ha bitat for southern DPS of North American green sturgeon and leatherback turtles.

The NMFS did not issue an incident al take statement with their Bi ological Opinion to the EPA. This decision was based upon the following: 1) th e adverse effects identified in the Biological Opinion will result from indir ect effects of subsequent Federa l actions carried out by the Corps

and other entities ca rrying out dredging and disposal; 2) thes e individuals actions are likely to cause take of ESA-listed species therefore it is mo re appropriate to consider exempting take on a case-by-case basis as such actions are proposed in the future; 3) the EPA’s action as described in the Biological Opinion does not authorize and will not itself resu lt in disposal of any dredged materials; and 4) the NMFS does not anticipate a ny take will result from the site designation and adoption of the SMMP. The NMFS further stated that “any further analysis of the effects of disposal of dredged material at th e disposal site and i ssuance of an incidental take statement with reasonable and prudent measures and non-discretionary terms a nd conditions to minimize take will be prepared when an ESA consultation on a dredging and disposal action is requested.”

Magnuson-Stevens Act and Marine Mammal Protection Act

EPA prepared an essential fish habitat (EFH) assessment pursuant to Section 305(b), 16 U.S.C. 1855(b)(2), of the Magnuson-Stevens Act, as amended, 16 U.S.C. 1801 to 1891d, and submitted

that assessment to the National Marine Fisher ies Service. The NMFS reviewed the EPA’s EFH assessment and Endangered Species Act (ESA) Bi ological Assessment and addendum thereto forYaquina Bay ODMDS Environmental Assessment and MPRSA Criteria Evaluation page 42 purposes of the Marine Mammal Protection Act of 1972, as amended (MMPA), 16 U.S.C. 1361

to 1389. The NMFS found that that all potential adverse effects to ESA-listed marine mammals, marine turtles, and designated critical habitat fo r leatherback sea turtles from the EPA’s action to designate the Yaquina North and So uth Sites are discountable or in significant. Those findings are documented in the Biological Opinion issued by the NMFS to the EPA on July 10, 2012. With respect to EFH, the NMFS concluded that the dispos al of dredged material will adversely affect water quality from increased turbidity in the water column, availability of benthic prey species, and safe passage during disposal. The NMFS provided two EFH Conservation

Recommendations to avoid or minimize the e ffects to EFH mentioned above. The NMFS recommends monitoring how fish interact with the disposal plume a nd conducting surveys to determine seasonal distribution, abundance, and hab itat use of EFH species and their prey at the disposal sites. The EPA will respond in a separate written response to the NMFS’

recommendations.

Coastal Zone Management Act

The Coastal Zone Management Act, as am ended, 16 U.S.C. 1451 to 1465, requires federal agencies to determine whether th eir actions will be consistent w ith the enforceable policies of approved state programs. EPA prepared a cons istency determination for the Oregon Ocean and Coastal Management Program (OCMP), the appr oved state program in Oregon, to meet the requirements of the CZMA and submitted that determination to the Oregon Department of Land Conservation and Development (DLCD). The DCLD concurred on May 7, 2012, with the EPA’s determination that the designation of the North and South Yaquina ODMD sites is consistent to the maximum extent practicable with the enforceable policies of the OCMP. The

DLCD based its concurrence on the informa tion contained in the EPA’s consistency determination and supporting materials, and on ex tensive conversations with the EPA. The Oregon Department of Fish and Wildlife (ODFW) participated in discussions with the EPA and the DLCD concerning the cons istency determination and both the ODFW and the DLCD encouraged the EPA to pursue future di sposal sites within the littoral zone.

National Historic Preservation Act

EPA initiated consultation with th e State of Oregon's Historic Pr eservation Officer (SHPO) to

address the National Historic Pr eservation Act, as amended, 16 U.S.C. 470 to 470a-2, which requires federal agencies to take into account the effect of thei r actions on districts, sites, buildings, structures, or objects, included in, or eligible for incl usion in the National Register.

EPA determined that no historic properties were affect ed, or would be affected, by designation of the Yaquina ODMDS. EPA did not fi nd any historic properties with in the geographic area of the

sites. This determination was based on an extens ive review of the National Register of Historic Districts in Oregon, the Oregon Na tional Register list and an a ssessment of cultural resources near the sites. On July 16, 2012, the State agreed with the EPA th at the designation of the North and South Yaquina Sites will have no e ffect on any known cultural resources.

Tribal Consultation

Government-to-government consultation letters were sent to the Coquille Indian Tribe, the Cow Creek Band of Umpqua Tribe of Indians, the Confederated Tribes of the Grand RondeYaquina Bay ODMDS Environmental Assessment and MPRSA Criteria Evaluation page 43 Community, the Confederated Tribes of the Siletz Indians, and the Confed erated Tribes of the Coos, Lower Umpqua and Siuslaw Indians. Trib al comments were also solicited during the NHPA process. The EPA specifically solicited comment from tribal officials. The EPA did not

receive comments from tribal officials.



### SELECTION OF OCEAN DISP OSAL SITES FOR FORMAL
DESIGNATION

Based on the evaluation of the criteria contained in 40 CF R Parts 220 through 228, the USACE

and EPA have determined that the North and S outh ODMDS are suitable for designation and use as disposal sites for ocean dumping of dredged ma terial, when disposal and site management is performed in accordance with the Site Manage ment and Monitoring Plan that was developed

under 40 CFR 228.9 and with use restric tions that will be specified as part of this designation.

The USACE and EPA have further determined that material dredged from the Yaquina Bay and estuary projects meet the criteria for dredge d material dumping. The North and South ODMDS are designated by EPA through formal rulemaking, adopting this ODMDS Evaluation/EA/Section 103 study and the a ppendices to supp ort this action.Yaquina Bay ODMDS Environmental Assessment and MPRSA Criteria Evaluation page 44 

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