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2
REGULATORY AND INSTITUTIONAL CONSIDERATIONS
Background
The legislative and regulatory structure governing dredged
navigational channels reflects a long history. A summary volume of
regulations states that "since colonial times, harbors and channels
have played an Important role in the nation's settlement, commercial
and industrial growth, and system of defense" (U.S. Army Corps of
Engineers, 1981a). As the provision of dredged navigational channels
has been taken to be a federal responsibility of both military and
commercial importance, primary responsibility for the design and
maintenance* of these works has been taken by the O.S. Army Corps of
Engineers.
In recent decades, other national interests have increased in
public importance, notably those of protecting the marine and coastal
environment and preserving oceanic resources. (A summary of
*Until 1978, the U.S. Army Corps of Engineers also performed
improvement and maintenance dredging with its own fleet of dredges,
and by contract with private industry. In 1978, following the
Industry Capability Program and a congressional act (P.L. 95-269), the
Corps initiated a Minimum Dredge Fleet for purposes of national
security or defense, preserving sufficient work to keep the fleet
operational, and allowed private industry to bid on all other dredging
work.
2 - 1
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2-2
environmental protection laws requiring compliance in navigational
projects is given in Appendix C.) Among the environmental questions
raised about dredging are the immediate and long-term effects of the
activity, the location of onshore or of fshore disposal sites for
dredged materials of different types, and the handling and disposal of
dredged materials containing toxic or hazardous substances, such as
Depone, oil, and heavy metals .
A lengthy 20-step process for gaining approval and public funds
for the construction of navigational projects has evolved in response
to these and other interests and objectives, illustrated in Figure 1.
Congress exercises control of the process at several stages, beginning
with initiation (Congress must request a feasibility study), and
including three to four separate congressional acts of authorization
and appropriation of funds. The district office (in which a
navigational project is located) of the U.S. Army Corps of Engineers
examines several engineering options, as well as their costs and
benefits, and prepares reports, including environmental impact
statements, for various levels of internal and external approval.
Public hearings are convened, and the review or concurrence (or both)
of the affected organizations, on its of government, and other federal
agencies is sought. Progress to step 16, congressional authorization,
takes about 6 years (and each year's activities depend on
congressional appropriations), after which several years may elapse
before the funds for advance engineering and design are appropriated.
The median time to complete the process was 15.2 years in the
mid-1970s. This was for 36 projects that were completed (many were
not) and for which the initial survey reports were submitted in the
late l9SOs and early 1960s (Heiberg, 1981~. The complexity of the
process and the number of decision makers have since increased. It is
estimated (no major Improvements to navigational channels have been
approved since 1976) that the process would take 20 years to 25 years
to complete today.
The Corps recently proposed accelerating the pace of this process
(but without reform or abbreviation, which requires congressional
action) by assembling "fast-track teams" that would conduct concurrent
studies and reviews , and (subject to congressional approval) by
dropping work on projects that have not been recommended for further
development (or have languished many years) and concentrating on those
that have been recommended for pursual (U.S. Army Corps of Engineers,
1982a ~ . The proposal aims to reduce the time spent by the Corps in
completing required studies and reviews from 12 years to 7 years.
While it is possible for ports or private interests to undertake
navigational projects that will be funded by sources other than the
federal government, a permit is required from the district engineer of
the Corps, who coordinates responses to the application from other
agencies and affected groups. A period of public notice and comment
is required. An environmental impact statement is also required, as
well as a public hearing. Memoranda of understanding between the
Corps and five other federal agencies state that decisions will be
made on these applications within 90 days of the public notice. The
Corps has also initiated a "pull" in place of "push" system for
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2-3
Figure 1 Planning, approval, ~ut,~oxization, and funding process for for n.vigationa1 projects.
1 2
3
4
Congress Congxes. ~pps-~1.tes Following appropriation of funds, District Engineer
authorizes fund. District Engineer conduct" o Investigates .11 altern.ti~.
Saudi initial public meting to revie. o Perform 11~1ted
drag t plan of aim, his Patti-. - technical fossil 11ty studies
opportunity to identify and discuss - en~lro~ntal asses~nte
~1 palm ~ ~-r~i~ ~ o _ ~ ~~. ~1
=~ ~i~1 _c elf_ ~ ~1~ ~i~
and envi ro~nta1 qu. 1 i ty
Survey Investig~t10n.
s
6
7
B
o ~~l~i~ Dimes ~~ me =~- ~~ ~1- ~t~, aim, 1~
Stage public o lnvestig.te. to~ul"~'on Tentative plan pro-ted groups, public resend co
meting to stage alternative" and discussed draft EIS and draft F.
discuss ~~t o Peafowl detailed
feasible - teeb~ical feasibil Sty studies
alter~tl~es - ~vi~ntal aunts
o Select. plan for proposal
in hi 1- ~ibi lip
0 =~ ~~ Hi
(ma ~ ~
( 15 has prior to late state
publ lc "eeti ng
0 N~ mat
10
11
12
o Reviews consents o Reviews o Considers Vie.e of o Aevie.e B~ ad rearm
~ ~ ~ ~ ~ - ~ ~ ~ _
o Prepares r~n~ - Film F. as arm: isle - States o Distributes for ~tel~ remix
- Fang EIS - f inal EIS - agencies o Files f inal EIS with EP^
- F1na1 FA o Issues public notice o Reviews and provides o Circulates to public for 30-day
requesting public views recommendations review period and to
be sent to Ward of - Final E1S governors, federal d_rt.ents
- ~1
Har~r. (BE-) o Tr~nesits to chief of
o Forwards reco_ndat ions engineers
to Bum
Ida ~ ~
I] 14 15 16
~~ ~ _ ~ ~ ~ ~ _
o Reviews received o Foz.~:ds remend o Revue." o Congress holds hearings
co_nte to Secretary of the away o Coordinates with me O Congress include. in Water
o M-~1 lea ·~t fog considex~tion o Pre-re~ his rec~nd.tion. Resource. ~velo~ent act
as appropriate - Final Report o Forbids final FR, final EIS. air other legislation
o Prepare. record - final E1S o ED co Congress (6 ho. ~ o President signs
of decision { ~D) - ~
-vie.
17 18 19
Project ^uthorizat10n
abut ~~- ~1 impel" ~
o Reviews Corps budget o Congress includes in guarantee to fulfill o Fo[.ulates pre-construct10n
o Su-it. to Congress ^~propri~t Ions act obl ignitions xequi led by 1~. planning genera1 design
0 Pxesident Signs f e.g., real estate, cost ~~r~nd. [C-)
aim, I, - _t~ EM ~ mire ~
Am, u~ ~- Ha. ~ aim, him
necessary -ter Quality
certif icates
- Issues peal ic Entice and
condoms .: least one p-1 ic
Meting (36 an.)
o ~~ ~~ ~1
(24 an.)
0 Initiates and complete.
~nstr~ien (60 go.
e ~~ _ Hi_
^~xt~ng Funds gate: AE6D to Construction Funding Construction
~]~ ~1
by Congress
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2-4
, . . ~
internal decision making to allow as many decisions as possible to be
made at lower levels, where local knowledge has been accumulated and
more timely decisions can be made, and to allow higher levels of the
Corps to "pull" up for consideration only the decisions that must be
made at that level.
These recent changes are only now being exercised. AS few major
deepening projects have been undertaken in the United States since
World War II, and only one planned for nonfederal funding,* the
principal criteria used in this country to determine the depths of
navigational channels are those of the U.S. Army Corps of Engineers.
The criteria consist of guidelines published by the Corps for the use
of district offices, and the practices of the districts established by
research or experience. A brief summery is given in the succeeding
section.
Criteria Used in the United States
to Determine Channel Depth
The Engineer Regulation "Deep Draft Navigation Project Design" (U.S.
Army Corps of Engineers, 1981b) states for determining the depths of
channels:
The channel depth must be adequate for the design
vessel draft, squat, trim, sinkage due to fresh water
conditions, location of salt water intakes on ship,
wave action and appropriate under keel clearance.
Minimum under keel clearance should be two feet for
soft channel bottoms and three feet for hard channel
bottoms. Squat is calculated for expected vessel
speeds and passing conditions for two way traffic
channels. Salt water intakes on vessels must be five
feet or more above soft channel bottoms. This
clearance is needed to prevent silt from being pulled
into the vessel condenser. Additional channel depth
may be provided by advanced maintenance dredging based
on the economics of dredging intervals and the need to
ensure appropriate under keel clearance between
dredging periods.
The references cited are the Engineer Manual, Tidal Hydraulics,
published in 196S, Devaluation of Present State of Knowledge of
Factors Affecting Tidal Hydraulics and Related Phenomena," also
published in 1965, and "Effects of Depth on Dredging Frequency,"
published in 1978 (U.S. Army Corps of Engineers, 1965a,b; Trawle and
Boyd, 1978).
Turning to the cited Engineer Manual,** two sets of criteria are
specified for determining channel depth: one for navigation, another
for ease of maintenance. These are briefly summarized here. The
factors considered by the panel in evaluating them are addressed in
detail in succeeding sections.
*Galveston, Texas
**Pertinent sections are reproduced in Appendix B
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2 -s
Navi gation
For Nazi gation, channel depth is generally considered to be determined
"by the in-motion draft of the design vessel, the density of water,
wave characteristics, the tidal characteristics, the characteristics
of the bottom, and the economics of greater depth as a factor to
reducing power requirements for the propulsion of the design vessel.''
Data for most of these factors are sparse and uncertain. The
Engineer Manual recommends site-specific data gathering and
-
consultation with ship owners and local pilots but acknowledges that
for calculation of such factors as squat, for example, "dependence
will have to be placed on estimates." The references cited for
calculations and considerations in estimating squat and other
important characteristics of the design ship are at least 20 years
old, some more than 30. These have not been updated. The rules of
thump given by the Engineer Manual for underkeel clearance are draft +
squat (3 ft) + rolling and pitching allowance (estimate) + clearance
(2 ft or 3 ft).
While the criteria for underkeel clearance have not been updated,
it is interesting to note that the more recent Engineer Regulation now
requires consultations with pilots and the concurrence of the U.S.
Coast Guard in channel dimensions and other aspects pertinent to the
safe use of the proposed channel, both in the preliminary and in the
final design stages. The Engineer Regulation also calls for
site-specific evaluation of physical environmental factors, including
gathering of baseline data and model studies, and recommends the use
of "[plertinent textbooks, research reports, or expertise from other
agencies."
The choice of the design shipts), as pointed out in the Engineer
Manual, is a crucial one, and this is clarified by the Engineer
Regulation as "selected from comprehensive planning studies of the
various types and sizes of vessels expected to transit the
channel...over the economic life of the project...." Usually the
largest vessel of the major commodity movers, it "is selected by
evaluating tradeoffs of delay cost incurred by larger vessels and cost
of increased channel dimensions. The maximum size vessel and least
maneuverable vessel in the fleet must be able to make a safe transit
[taking into account special conditions that may be imposed--for
example, speed limits' use of high tides for additional water depth,
one-way traffic, tug assistance!."
There are regulatory and institutional concerns beyond those of
the U.S. Army Corps of Engineers: those of port authorities and the
U.S. Coast Guard, for example, about the consequences of groundings.
These may result in the "special conditions that may be imposed."
While many vessels can strike a soft channel bottom or ground without
harm, all groundings must be reported to the U.S. Coast Guard under
the Port and Waterways Safety Act of 1972, and a fine may De levied
against the master or pilot.
Maintenance
The Corps has expended considerable ef fort investigating, modeling,
and adding to the understand' ng of the hydrology of channels,
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20
estuaries, and rivers. This understanding is essential to several
missions of the Corps--for example, engineering design and
construction of flood control and water-resources projects--and to the
interactions of these works with navigational channels.
One updated reference in the Engineer Regulation is Trawle and
Boyd (1978) and, by parity of reason, Trawle (1981b). Trawle and Boyd
(1978) is the first and Trawle (1981b) the second report in the series
, _
Effects of Depth on Dredging Frequency. The first report discusses
:
the evidence from questionnaire surveys of Corps districts respecting
overdredged depths (or "overdepth dredgings. Overdredged depths are
of two types (see Figure 2~: One is the "allowable pay overdepth," an
additional depth for which the Corps agrees to pay the dredger to
ensure that the design depth is achieved--that is, allowing for the
inaccuracies of dredging and surveying. The other is "advance
maintenance overdepth" or "purposive overdepth" for (1) maintaining
project depth in rapidly shoaling areas, (2) reducing the frequency or
maintenance dredging, or (3) allowing more efficient dredging
operations, if deeper cuts are more cost-effective, or for some
combination of these reasons. The surveys indicated that in all
coastal districts the allowable pay overdepth varies from 0 ft to 3 ft
(0.9 m}, most clustering at 2 ft (0.6 m), for channels from 30 ft to
47 ft (9.1 m to 14.2 m) deep. This "plus 2 ft" seems to be a rule of
thumb that has evolved.
The surveys also revealed that past shoaling history seems to be
the main determinant of advance maintenance dredging in the coastal
districts (amounts varied from 1 ft to 8 ft (0.3 m to 2 e4 m) nut are 3
ft (0.9 m) or less in 84 percent of the projects) and that the method
of assessing past shoaling varied from district to district.
Specifically, Trawle (1981b) indicates that three techniques and
formulas were being used to determine whether and where advance
maintenance dredging was needed, all less than adequate, and that
hydrographic surveys were generally infrequent (Table 3~. The second
report offers a formula for calculating shoaling rates as a function
of the volumes dredged in the past (from annual records of dredging
work) to maintain project depth in segments of a channel, and
correcting with hydrographic surveys. One object of this technique
and formula is more efficient scheduling of maintenance dredging,
another is to encourage variable advance maintenance dredging (that
is, by channel segment} for fast-shoaling areas. An implicit
objective of the report seems to be to bring these practices into
conformity with an adequate standard and encourage more frequent
hydrographic surveys.
Implications
The glacial pace of the multistage process for approvals,
congressional authorization, and other steps to be completed, and the
number of years over which the process itself has evolved, have
several Implications for channel design. First, the validity of
original assumptions and estimates attenuates with time, necessitating
update studies and reexamination of needs, costs, and benefits. The
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2-7
Figure 2 Two types of overdredged depths in navigational channels:* (a) typical
dredged channel, showing allowable pay overdepth; (b) dredged channel
with allowable pay overdepth and advance maintenance dredg~ng overdepth
WAJER SURfACE _
~ ~ _ n—T11~4
~_ DEP~ ~ AU - ORJZED OR RE~ R")
_ — _
'/~/~N
(a)
(b)
, ,
SLOPE
_ALLOWABLE PAY OVERDEPnt (USUALLY ~ OR 2 F~
I ~
r ~
WATER 9~1RfACE ~
`sorrou WID7H (AU"IOPIZED OR RE - IRED)
- _ DREDGD
DEP TH
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_ DEPTH tAUTHORtZED OR REOUIREa
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40V - CE ~~NT - - CE (OVERDEP - )
p_ALLOW - LE PAY OVERDEP~
*SOURCE: M. J. Trawle and J. A. Boyd, Jr. (1978), Effects of Depth on Dredging
Frequency, Report 1, Survey of District Offices, Technical Report H-78-5
(Vicksburg, Miss.: U.S. Army Engineer Waterways ExperLment Station),
May 1978, p. 6.
OCR for page 20
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2 - 9
deepening of the major channel serving Tampa Bay, for example, was
authorized in 1970. The final environmental impact statement was
submitted in 1971, an updated statement was filed in 1975, the draft
of a supplement in 1976, and the final supplement in 1977. The
original estimated cost to deepen channel segments was $97.5 ~ [lion.
In 1981, the estimated cost was $178 million and this included
reductions of more than $12 million owing to favorable bids, to work
completed under bid, and to the savings represented in dredging to
depths a foot less than those authorized (U.S. Army Corps of
Engineers, 1982b).
While much may still remain valid from earlier studies, the time
scale of the decision making process is far longer than the time scale
of major changes in the world shipping fleet. Less than 5 percent of
the ships in the world's merchant fleet are 25 years old or more:
more than 59 percent are under 10 years old (Lloyd's, 1980~. The
design ship used to specify channel improvements may pass from drawing
board to desuetude before channel improvements receive final approval
and work begins.
Second, the nature of this process (and the time needed to
complete it) discourages innovation. Approximately 1 percent of the
total budget of the U.S. Army Corps of Engineers is for research, and
this must be divided among several subjects of equally preening
importance to the missions of the Corps. As described in succeeding
sections, the number and complexity of the factors that need to be
understood to determine the depths (and other dimensions) of
navigational channels demand considerable research. Some of this may
be undertaken by the districts on passage of the legislation
authorizing a navigational project--for example, model and simulation
testing of the channel design for various vessels and unique features
of the local environment--as their budgets allow. Model tests,
simulations, and intensive local data collection are generally
expensive. In their absence, design depth is usually based on
empirical rules ("rules of thumb") set out in Corps publications, with
additional depth ts) for achieving the design depth and advance
maintenance dredging.
Furthermore, the design and engineering undertaken after
authorization are bound by the terms of the authorizing act. Even in
areas of a particular project's design and engineering that may allow
some latitude, the nature of the decision making process and the
number of decision makers involved ensure that changes will be
addressed conservatively, and in terms that are readily understood or
familiar. These considerations, together with the very long tome
needed to plan and secure approval of navigational projects, tend to
fossilize the rules of thumb for channel depth.
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Representative terms from entire chapter:
maintenance dredging
