Coastal & Port Engineering Considerations of the Jacksonville Harbor Deepening Study

Coastal & Port Engineering Considerationsof the Jacksonville Harbor Deepening Study

Kevin Bodge, Ph.D., P.E.Port & Coastal Engineer

Senior Vice President -- Olsen Associates, Inc.

Coastal & Port Engineering Considerationsof the Jacksonville Harbor Deepening Study

Physical Impacts

1. River hydraulics (flow, levels & sedimentation)Deeper, hydraulically-efficient artificial channel -- increases upstream salinity -- increases water levels -- changes flow patterns

Coastal & Port Engineering Considerationsof the Jacksonville Harbor Deepening Study

Physical Impacts

1. River hydraulics (flow, levels & sedimentation)Deeper, hydraulically-efficient artificial channel -- increases upstream salinity -- increases water levels -- changes flow patterns

2. Storm water levels-- Tide ranges increase up to 0.4 feet-- Storm tides not described

Coastal & Port Engineering Considerationsof the Jacksonville Harbor Deepening Study

Physical Impacts

1. River hydraulics (flow, levels & sedimentation)Deeper, hydraulically-efficient artificial channel -- increases upstream salinity -- increases water levels -- changes flow patterns

2. Storm water levels-- Tide ranges increase up to 0.4 feet-- Storm tides not described

3. Salt water intrusion-- impacts to aquifer . . . not included

Coastal & Port Engineering Considerationsof the Jacksonville Harbor Deepening Study

SOME OF THE STUDIES NOT IN THE DRAFT REPORT FOR PUBLIC REVIEW & COMMENTS

Coastal & Port Engineering Considerationsof the Jacksonville Harbor Deepening Study

Physical Impacts, Cont’d4. Salinity

-- The Corps claims that natural changes in salinity cause more stress than the project’s changes.-- The impacts are real, but not clearly presented-- Fish & shrimp studies etc. are still ongoing

NO ACTION (No Project) 50-Ft PROJECT

Coastal & Port Engineering Considerationsof the Jacksonville Harbor Deepening Study

Physical Impacts, Cont’d

5. Ship Wake and Bank Erosion-- Corps study claims no increase in ship wake, but that is based upon the current design vessel.-- Deeper channel Bigger Ships Greater Ship Waves

970’ ship length at 15 knots: wake = 3.7’1260’ ship length at 15 knots: wake = 6.8’ (84% increase)

970’ ship length at 10 knots: wake = 0.4’1260’ ship length at 10 knots: wake = 1.0’ (150% increase)

Coastal & Port Engineering Considerationsof the Jacksonville Harbor Deepening Study

Physical Impacts, Cont’d

6. Offshore Disposal Area-- Construction requires disposal of 18 million

cubic yards (mcy)-- Existing offshore disposal area capacity =

3.3 mcy-- Expanded offshore disposal area close to

sand borrow areas.

Coastal & Port Engineering Considerationsof the Jacksonville Harbor Deepening Study

Fiscal Impacts

1. Initial Construction CostFed: $350M (48%) Local: $384M (52%)

2. Maintenance Dredging Costs-- Fiscal projections are not included in report-- Local cost-share increases from 0% to 50% !

Dredging requirements will increase by 130,000+ cy/yror, about $1.2M per year.

Probable annual dredging req’t = 1,540,000 cy/yrProbable equivalent total cost = $14 million / yearProbable NON-FEDERAL cost = $7 million/year.

My estimates, not in report