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1
INTRODUCTION
As elaborated in succeeding chapters of this report, several
considerations affect decisions about the depths of dredged
navigational channels. These can be separated into two general
categories, the requirements of navigation (principally the underkeel
clearance required in a variety of physical conditions) and those of
achieving and maintaining dredged depths, but in actuality, they must
be considered together. AS noted by Kray (1973), "=is is to provide
for smooth operation and to avoid costly accidents for inadequately
designed channels and maneuvering areas, and an excessive cost of
constructing and maintaining the overdesigned navigational facilities."
Table 1 indicates the scope of concerns for navigation and
maintenance in the channels of deep-draft ports and harbors--those 30
ft or more in depth.* The costs of dredging to maintain channel
depths and the tonnages of trade accommodated by these channels are
obviously considerable.
*The U.S. Army Corps of B gineers defines deep-draft navigational
projects as those 14 ft or more in depth. The concern of this study
is the navigational channels of the major coastal ports and
harbors--the 85 ports and harbors reached by navigational channels 30
ft or more in depth.
1-1
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Table 1 Costs to maintain channels and harbors of major ports in the United
States by dredging, and 1978 trade, by tonnage*
Annual Average
Port Depth Maintenance Cost 1978 Tonnage
(in feet) (in thousands)
Alaska
AlabAt'~a
Anchorage Harbor 35 $1,453.6 2,226,200
Mobile Harbor 40 5,303.2 17,336,800
California
Humboldt Harbor & Bay 35 1,243.9 1,435,900
Stockton 30 979.8 2 ,277 ,600
Suisun Bay Channel 30 147.4 1,164,800
San Pablo Bay 35 503.1 7, 082,600
Oakland Harbor 35 1,143.3 6,232,500
Richmond Harbor 35 1,182.1 15,902,900
San Francisco Harbor 40 39.1 50,4()L,500
Los Angeles-Long Beach 45 144.0 60,780,900
Harbor
San Diego Harbor 35 0 2,360,;200
Connecticut
Bridgeport Harbor 35 2;24.8 3,732,600
New Haven Harbor 3S 566.9 11,323,200
New London Harbor 33 7.8 2,550,600
Delaware
Florida
Georgia
IWW Delaware to 32 10,322.9 10,226,200
Wilmington Harbor 35 1,851.0 2,162,100
New Castle 35 1,202.2 8,278,;200
Delaware City 35 516.5 3,556,400
Charlotte Harbor 32 1,322.5 1,067,300
Canaveral Harbor 36 2,438.7 2,341,500
Panama City Harbor 32 210.0 282,900
Port St. Joe Harbor 35 167.8 326,200
Pensacola Harbor 33 633.6 1,538,600
Palm Beach Harbor 33 209.9 728,600
Jacksonville Harbor 38 3,098.7 13,119,400
Key West Harbor 30 25.7 202,600
Tampa Harbor 36 2,309.4 46,866,400
Miami Harbor 38 20.3 3,098,900
Port Everglades Harbor 42 83.7 11,929,300
Brunswick Harbor 30 3,490.5 1,259,000
Savannah Harbor 38 10,429.8 10,633,400
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Annual Average
Port Depth Maintenance Cost 1978 Tonnage
(in feet) (in thousands)
Hawaii
Port Allen Harbor 35 63.7 89,300
Nawiliwili Harbor 35 535.3 765,900
Kahului Harbor 35 671.2 1,922,100
Hilo Harbor 35 352.2 1,272,700
Honolulu Harbor 45 167.7 7,140,500
Louisiana
Calcasieu River & Pass 40 7,336.1 13,563,000
New Orleans 40 16,661.9 77,231,400
Baton Rouge 40 18,297.5 123,937,800
Maine
Portland Harbor 35 613.4 21,964,800
Maryland
Baltimore Harbor 42 2,477.6 37,074,600
& Channel
Massachusetts
Cape Cod Canal 32 4,096.6 12,226,600
Fall River Harbor 35 133.2 4,642,300
Boston Harbor 40 181.1 24, 700
Mississippi
Gulfport Harbor 30 1,899.2 950,000
Pascagoula Harbor 38 2 ,485 .5 18 ,258,200
New Hampshire
Portsmouth Harbor 35 140.7 3, 293, 300
New Jersey
Camden 30 264.6 1,787,400
Gloucester 35 245.4 1,690,000
Paulsboro 40 2,522.9 17,372,800
New York
Hudson River, Albany 32 1,907.5 10,440,500
New York-New Jersey 45 12 ,905 .7 119, 317 ,600
North Carolina
Morehead City Harbor 40 1,969.6 2,069,400
Wilmington Harbor 38 3,041.6 7,422,800
Oregon
Yaquina Bay & Harbor 32 1,379.2 668,500
Coos Bay 45 3,652.3 S,218,900
Portland 40 12,567.1 16,524,952
Astoria 40 881.7 1,159,300
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Annual Average
Port Depth Maintenance Cost 1978 Tonnage
_ {in feet} (in thousands)
Pennsylvania
Penn Manor 40 1,376.6 4,041,200
Philadelphia 40 6,702.0 37,067,600
Chester 35 4.1 28,100
Marcus Hook 40 3,446.4 23,731,900
Puerto Rico
Mayaguez Harbor 30 106.7 335,300
Ponce Harbor 30 77.7 911,400
San Juan Harbor 48 852.9 10,147,800
South Carolina
Charleston Harbor 35 5,816.9 9,548,800
Texas
Brazos Island Harbor 36 3,116.6 1,162,900
Matagorda Ship Channel 38 2,610.3 3,963,200
Freeport Harbor 36 3,590.8 18,657,400
Galveston Harbor 40 1,638.8 7,004,300
& Channel
Corpus Christi 45 ~ 6,202.1 46,244,500
Sabine Ports 40 7,981.8 69,740,900
Houston 40 8,312.5 81,221,825
Texas City 40 1,954.1 23,627,800
Virginia
Norfolk Harbor 45 2,801.7 25,286,900
Newport News 45 932.0 5,740,900
Washington
Grays Harbor & 30 4,668.4 2,664,000
Chehalis River
Vancouver 40 1,185.5 1,558,800
KalamA 40 199.6 262,500
Longview 40 4,645.5 6,108,500
Everett Harbor & 30 457.0 2,167,900
Snohomish River
Bellingham Harbor 30 140.8 891,000
Seattle Harbor 34 376.5 11,357,500
Ediz Hook-Port Angeles 30 19.3 2,774,100
Tacoma Harbor 35 44.5 9,667,300
a Rounded to the nearest hundred tons
*SOURCE: From U.S. Senate Committee on Environment and Public Works (1981),
Report to Accompany S. 1692, National Harbors Improvement and Main-
tenance Act of 1981, 97th Congress, 1st Session, pp. 29-32.
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Thus, economic considerations (specifically excluded from the
panel's analysis) dictate that the depth and other dimensions of a
channel be minimal, but consistent with the safe passage of ships
calling at the port or harbor. These ships,-over the past decade and
a half, have been increasingly larger. Some examples of common ship
types and their-design data are given in Table 2.
The hydrodynamic forces and effects experienced by these vessels
in navigational channels differ markedly from those experienced in the
open ocean. The draft and attitude of a vessel change continuously
while it is under way in a navigational channel, owing to the combined
effects of natural and ship-generated forces and the dimensions and
layout of the channel. Vertical excursions present the danger that
the vessel may ground or strike bottom. Ships are rarely reinforced
in the areas most likely to be scratched or breached by grounding or
striking bottom, nor is such reinforcement feasible, owing to the
enormous forces that develop in such an accident. Thus, these
casualties present risks from the leaking of hazardous or polluting
cargoes. Damage to the ship, loss of cargo, and containment and
cleanup operations can be expensive: the breaching of the tanker
Tamano inbound to Portland, Maine, in 1972 cost more than $2 million
in vessel damages and pollution mitigation.
The designed configuration of a navigational channel, according
to the National Waterways Study (1980), "influences the probability of
vessel casualties." In considering strategies to enhance the safety
of domestic waterways, the report states: "the only single action
which by itself could reduce accidents is the structural improvement
of the waterways."
Depth is an important component of the designed configuration of
a navigational channel. In the interest of providing the technical
basis for design and maintenance of dredged navigational channels, the
panel undertook an evaluation of the criteria used to determine
channel depths in the United States. The panel reviewed
o Criteria used in the United States for channel depths;
o Considerations important to the evaluation of channel depths;
o Voluntary consensus standards developed by international
organizations; and
o Criteria used in other maritime nations with highly
developed port technology.
It also assessed the adequacy of the criteria used in the United
States.
The results of the panel's review and appraisal are briefly
summarized in succeeding chapters of this report: Chapter 2 discusses
regulatory and institutional issues. Chapter 3 deals with
considerations important to determining channel depth (ship movements
and sedimentations. Chapter 4 addresses the adequacy of criteria for
dredged depths of navigational channels and compares those of the
United States and other countries, international organizations, and
shippers. Chapter 5 sets out the panel's conclusions and
recommendations. Abstracts compiled by the panel in a preliminary
search of the literature constitute Appendix A.
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Table 2 Gown ship types and their design data
Cargo Capacity Length Beam
"me (dot, unless noted) (ft.) (ft)
Draf t
(ft)
Ferry STAMEN ISLAND 2,721 310 70 12
Tugboat JALBAR 1,010 126 36
Bulk
AI.TNES
Tanker MARINDUS
4,550 301
10,000 470
Shrine FRANK CA=E 23,000 643
Tender
49
60
85
21
23
25
Tanker EXXON GALVESTON 27,240 552 95 29
Dry Cargo A~ITRITI 16,952 468 69 31
Container~hip EUROLINER 40,800 798 100 32
ROMEO BOOGABm.T ~ 31,500 749 105 35
Barge Carrier YF:t IUS TUCHIK 36,382 874 115 36
Navy Tanker HUDSON 37,276 672 89 36
LNG Carrier EL PASO SOUTHERN 126,000m3 846 135 37
Ref. ined Product BALDBVTTE 244bbl 665 84 31
Tanker
Tanker ESSO PORTI`AND 50,084 645 120 37
Crane Ship
SARITA
42,000
677
121
37
Barge Carrier AIMERIA LYKES 38,410 876 106 39
Dry Cargo AMERICAN TRADER 29,749 820 100 41
Containership KORRIGAN 57,200 947 43
Ore/Bulk/Oil ULTRASEA 83,437 893 106 46
Bulk WORLD DULCE 133,361 570 142 52
Bulk SAMRAT ASHOK 72,600 856 58
ore SlIINRXU MARIJ 88,800 959 59
Tanker SAN DIEGO 188,500 952 166 59
Ore/Bulk/Oil RHETORIC 77,000 996 - 60
Ore/Oil BRAZILIAN WEALTH 141,800 1099 72
Bulk/Oil LAUREL W=A~1 72,300 940 72
Tanker ESSO PACIFIC 508,000 1280 233 83
a
a Not acac~odated by dredged channels of the United States
Representative terms from entire chapter:
channel depths
