Dredging, Disposal Management and Impacts on Lake Sediments

1. US Army Corps of Engineers Dredging, Disposal Management and Impacts on Lake Sediments

2. US Army Corps of Engineers Great Lakes Harbors • Corps maintains 139 channels and harbors (total harbors on the Great Lakes is over 200) • 68 commercial harbors • Represents 24% of Nation’s commercial harbors • 71 recreation harbors • Represents 12% of Nation’s recreation harbors • About 700,000 recreation vessels traverse the lakes annually Duluth Harbor, MN Commercial Arcadia, MI Recreation

3. US Army Corps of Engineers Operation & Maintenance Budget • Annual budget to operate and maintain Corps navigation projects on the Great Lakes ranges from $82M to $89M • Includes surveys, dredging, structure and lock maintenance • Cost to dredge Corps projects ranges from $16M to $24M annually, with an average of $20M • Federal yardage dredged is 3.5 - 4.0 million cubic yards • Including non-Federal harbors yardage is 5 - 6 million cubic yards

4. US Army Corps of Engineers Great Lakes Dredging • Corps dredges 26 - 41 projects annually • Average is about 35 for deep and shallow draft harbors • Average 9 recreation harbors • In FY 2000 Corps dredged 41 projects • 25 were commercial and 16 recreation • In FY 2001 Corps estimates 40 projects will be dredged • 24 are commercial and 16 recreation

5. US Army Corps of Engineers Dredging (con’t) • Did the low lake levels in 1999 & 2000 change the way the Corps dredges within the Great Lakes? • No • Projects are dredged to depths to meet user needs, up to authorized depths below low water datum (LWD) • LWD establishes the depth to which projects are maintained • Harbors dredged to project depth whether lake levels are high or low • Some channels maintained to less than authorized depth • Projects are dredged based on shoaling rates and commercial importance (priority) of the project • High lake levels allow dredging at recreation harbors to be deferred

6. US Army Corps of Engineers Dredging (con’t) • Commercial navigation industry was impacted by low lake levels in 1999 and 2000 • Industry was used to above average lake levels • One inch loss in draft equates to a loss of 270 tons of cargo carrying capacity for a 1000-foot vessel • In general, lake levels do not impact dredging • Some impact at tributaries entering the lake • Sediments drop out quicker with lower lake levels • Corps now has authority to dredge deeper • Section 343, WRDA 2000, allows Corps to dredge to provide authorized depths when lake levels go below LWD

7. US Army Corps of Engineers Dredging (con’t) • Did the Corps dredge all harbors which had shoaling problems in 2000? • Funding constraints prevented dredging at some recreation harbors • Previous high lake levels masked the issue of a lack of funding for all needed dredging • Some harbors have issues preventing dredging • Lack of a disposal site • Other environmental issues

8. US Army Corps of Engineers Dredging (con’t) • If low lake levels continue in FY 2001, what impact will this have on the way the Corps dredges? • Commercial harbors will receive highest priority • Funding constraints will impact some recreation harbors • The Corps will dredge as many harbors as funding allows • In FY 2000 the Corps dredged more harbors than it had originally scheduled due to dropping lake levels

9. US Army Corps of Engineers Confined Disposal Facilities • Disposal of dredged material used to be unconfined and placed in the open water • Least cost alternative • Lake water quality degradation dictated alternative disposal methods be investigated • Public Law 91-611 provided funds to construct CDFs • First CDF constructed in early 1970s • 44 CDFs constructed on the Great Lakes • Current disposal methods include open water, beach nourishment, or a CDF

10. US Army Corps of Engineers Dredging and Its Placement • Quantity dredged averages 3.6 M CY of sediments • Cost to dredge averages $20 M annually • About a 50 - 50 split between confinement and open lake disposal, but recent trend is towards more confinement • Confined disposal accounts for 55 percent of material • Open lake disposal or beach nourishment accounts for 45 percent of material Pt. Mouillee

11. US Army Corps of Engineers Great Lakes Dredged Material Testing & Evaluation Manual • Regional guidance developed by USEPA • and Corps • Applicable to dredged material discharges • to Great Lakes, connecting channels, and • tributaries • Tiered testing approach consistent with national • guidance, but using regionally chosen methods • Available online: • www.epa.gov/glnpo/sediment/gltem

12. US Army Corps of Engineers Confined Disposal Facilities • Existing CDFs won’t last forever • Slightly less than half are filled or inactive • Corps is assessing each project’s disposal needs • Dredged Material Management Plans developed to assess disposal needs over a 20 year period • All new CDFs require cost sharing with a sponsor • WRDA 1996 establishes cost sharing requirements • Non-federal cost linked to project depth requirements • Approximately from 10 to 50 percent of total cost • Allows for private disposal facilities

13. US Army Corps of Engineers Disposal Management • What can be done to extend the useful life of existing containment facilities? • Better consolidation of dredged material • Use of ditches to drain water • Beneficial re-use of dredged material • Beach & near-shore nourishment • Mining and treatment of material for some productive use • habitat restoration, landscaping, road construction fill, agricultural soils, strip mine restoration, or temporary cover for landfills

14. US Army Corps of Engineers Disposal Management (con’t) • Beneficial use of dredged material offers a sustainable long-term management option for dredged material • Regulatory and public perception issues are major obstacles to beneficial use • State regulations lack a coordinated regulatory approach to beneficial use • Better communicate pertinent information to the public • Institutionalize the concept that dredged material is a valuable resource

15. US Army Corps of Engineers Disposal Management (con’t) • The Corps is dredging the same quantity of sediments while the quality of it is improving • Sources of pollutants becoming less • Dredging reduces pollutants within channels • Requirement for confining dredged sediments will continue in the future • The Public and State agencies will require it • Requirements for dredged material management will increase rather than decrease in the future • Trend is to confine more dredged material • Unused capacity of CDFs is diminishing

16. US Army Corps of Engineers Cooperative Efforts • Corps is working with the USEPA and State / local agencies to clean up toxic harbor sediments • Examples • Ashtabula Harbor • Indiana Harbor • Waukegan Harbor

17. US Army Corps of Engineers Impacts on Lake Sediments • Effect of lower lake levels and vessel traffic • Vessels closer to channel bottom • Prop wash aggravates sediments • Suspends toxic materials within the water column • Effect of lower lake levels on tributaries • More scour occurs near the mouth of a tributary • Causes more sediments / toxic materials to enter lake • Sediments more mobile with low lake level conditions • No studies which quantify the effect between low lake levels and toxic sediments • Conceptual efforts and cannot quantify numbers / impacts

18. US Army Corps of Engineers Dredging, Disposal Management and Impacts on Lake Sediments Questions ?