Modeling Shallow Draft and Deep Draft Traffic in Deep Draft Harbors

1. Modeling Shallow Draft and Deep Draft Traffic in Deep Draft Harbors September 15, 2011 Joe Berlin Anne Watkins

2. National Economic Development Benefits of Channel Widening • Widening projects decrease congestion within a waterway or harbor • Allow more vessels to pass each other, reduce one-way restrictions • Decrease in vessel wait time decreases vessel operating costs • Decrease in vessel operating costs are considered NED benefits

3. National Economic Development Benefits • Contributions to national economic development (NED) are increases in the net value of the national output of goods and services, expressed in monetary units. Contributions to NED are the direct net benefits that accrue in the planning area and the rest of the Nation. Contributions to NED include increases in the net value of those goods and services that are marketed, and also of those that may not be marketed.

4. HarborSym - Overview • Data-driven model of vessel traffic • Simulates vessel traffic moving in and out of a harbor using navigation rules • Calculates vessel wait times and operating costs • By comparing the operating costs of different scenarios, USACE planners can determine the NED Benefits of improvement alternatives • Designed to model deep draft traffic, but can be adapted to model shallow draft traffic

5. HarborSym - History • Development by USACE Institute for Water Resources (IWR) starting in 2002 • HarborSym Widening – certified in 2011 • HarborSym Deepening – certification in 2012 • Once a model is certified, USACE planners are required to use it

7. Port of Corpus Christi (2007-2008) • Ranked 5th in U.S. by tonnage • Handled over 76 million tons in 2008 • 55 million tons foreign • 21 million tons domestic • Mostly crude oil and petrochemical products • Almost 1,500 deep-draft vessel calls in 2007 • Approximately 3,350 barge tows

8. Corpus Christi Ship Channel • Currently at 45’ deep, proposed depth 52’ • Width within Corpus Christi Bay is 500’ in Cut A and 400’ in Cut B • Studying widening Cuts A & B to 530’ • Studying adding two 200’ wide by 12’ deep barge shelves in Cut B

9. Corpus Christi Ship Channel

10. Corpus Christi Ship Channel

11. HarborSym Node Network

12. Barge Traffic in the U.S. • Generally bulk commodities • Grain • Petrochemicals • GIWW is 12’ deep x 125’ wide • Tank barges are 54’ wide x 300’ long • Dry bulk barges are 35’ wide x 195’ long

13. Barge Traffic in CCSC • Barges share the ship channel with deep draft vessels • Vast majority tank barges (petrochemicals) • Up to 6-barge tows • Most tows consist of 2 barges • A tow consisting of 2 tank barges would be 300’ long x 108’ wide

14. Selected Hourly Operating Costs

15. Using HarborSym to Determine Barge Shelf Benefits • Deep-draft vessels designated “Priority” vessels • Barges should not cause deep-draft vessels to wait • Reaches cannot be two different depths • Used combined beam width and combined draft rules • Sets the maximum beam/draft of passing vessels, but not the maximum number of vessels

16. Combined Beam Rule • Combined Beam = 0.7 of channel width • 530’ channel + two 200’ barge shelves = 930’ • Maximum combined beam = 651’ • Combined beam without barge shelves = 0.62 (329’) • Would allow two crude oil tankers to pass in channel and two 6-barge tows to pass in barge shelves

17. Combined Draft Rule • Combined Draft = 104’ • Channel depth = 45’ • Combined draft maximum without barges = 80’ (from pilots) • Would allow two 40’ vessels to pass in channel, and two 12’ barges to pass in barge shelves

18. HarborSym Modeling Constraints • Cannot have two depths for the same reach • HarborSym rules designed for deep draft traffic • With some limited exceptions, cannot make rules apply only to certain types of traffic • Hard to ensure 3 deep draft vessels don’t pass using the barge shelves • Must check output files closely

19. Barge Shelf NED Benefits • Three Scenarios: • Without Project • Widening (with 45’ depth) • Widening Plus Barge Shelves (with 45’ depth) • Barge Shelf NED Benefits = “Widening Plus Barge Shelves” –“Widening”

20. HarborSym Output - 2007

21. Benefits of Barge Shelves