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The Value of Maintenance Dredging. Jim Kruse Texas Transportation Institute August 2007. Overview. One task of a comprehensive study on value of Texas ports Task 6: Channel Siltation and National Economic Development Benefits of Maintaining Authorized Depths. Focus of Analysis.
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The Value of Maintenance Dredging Jim Kruse Texas Transportation Institute August 2007
Overview • One task of a comprehensive study on value of Texas ports • Task 6: Channel Siltation and National Economic Development Benefits of Maintaining Authorized Depths
Focus of Analysis • Focus strictly on two cost components: • Cost of Marine Transportation • Cost of Maintenance Dredging • Inverse of the Corp’s National Economic Development (NED) Benefits • Rather than benefit to be achieved if action taken, here it’s costs incurred if action not taken
Focus of Analysis • Other costs that could be studied: • Relocations • Changes in activity levels • Diversion of cargo • Loss of ability to compete • Vessel security • Increased traffic rise in charter rates/collisions
GIWW (for all of Texas and in three separate reaches) Lower – Corpus Christi to Brownsville Middle – Galveston to Corpus Christi Upper – Sabine to Galveston Texas consolidated Chocolate Bayou Arroyo Colorado (Port of Harlingen) Channel to Victoria List of Waterways
Colorado Lock Data • Selected 4 mths of data randomly • Calculated: • Average draft for barges with greater than 8 feet of draft • Average empty draft • Weighted average tons per barge for barges with greater than 8 feet of draft • Tons of cargo per foot of draft • Average number of barges per tow when barges draft more than 8 feet
Draft Assumptions • Baseline: 2005 • Barges limited to 8 ft • Towboats limited to 9 ft
Barge/Tow Assumptions • Towboat: 1800-2000 HP category • Speed of 5 mph was assumed • Tank barges: 297.5’ x 54’ x 12’ tank barge without coils • Hopper barges: 195’ x 35’ x 12’ covered hopper
Costs • USACE Economic Guidance Memorandum 05-06: Shallow Draft Vessels Operating Costs for 2003 • Adjustment made to fuel cost due to dramatic increases in fuel costs since 2003 • Other operating costs were inflated using Inland Waterways Towing Transportation Producer Price Index
Selection of Tows to Analyze Draft of Each Tow (Barges) Excess Draft Current Draft (8’ 9”) Silted Draft (8’)
Effect Cargo to be Reallocated Increased Cost Per Ton Draft of Each Tow (Barges) Current Draft Silted Draft
Effect New Shipments Draft of Each Tow (Barges) Current Draft Silted Draft
Cost-per-ton Penalty Cost of 400–mile Voyage (Hopper): $24,170 With 1,887 tons/barge, cost per ton is $5.338 With 1,692 tons/barge, cost per ton is $5.954
Cost-per-ton Penalty 1,692 tons times ($5.954 - $5.338) What happens to the other 195 tons?
Additional Voyages Each additional voyage @ $24,170
Asphalt Barge Kirby 27702300 x 54 x 12 Current Draft (8’ 10”) 3,208 tons Silted Draft (8’) 2,810 tons Cost per ton over 431 miles: $5.69 vs $6.49 ($2,248 extra)
Shallower Still? • For GIWW and Channel to Victoria anywhere from 8% to 28% of the towboats working these channels could find themselves incapable of taking on a full store of fuel and water • Reduces their efficiency even further or causes them to be redeployed elsewhere
Inspirational Closing Thought • When the chips are down…. • the buffalo is empty.