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OCR for page 45
rag I'
The Criteria Options'
and [valuation
OCR for page 46
OCR for page 47
4
Preservation Options
and Evaluation Criteria
THE OPTIONS
The committee identified and evaluated ten principal
options, some of which foreclose others. For example, relo-
cation would eliminate from immediate consideration the con-
struction of a seawall, and a seawall would make subsequent
relocation difficult or impossible. Other options, such as
beach nourishment or breakwater construction, could be used
in combination. The committee did not evaluate every pos-
sible option, but selected the following as worthy of consid-
eration:
Incremental relocation of the lighthouse intact
Rehabilitation of the groinfield without revetment
Rehabilitation of the groinfield with revetment
Seawall/revetment
Artificial- reefs
· Offshore breakwaters and groinfield rehabilitation
Deployment of artificial seagrass
Continuing beach nourishment
No action
New lighthouse
CRITERIA TO EVALUATE PRESERVATION OPTIONS
To evaluate the options, the committee developed a set of
criteria or tests against which to judge the options. The
47
OCR for page 48
48
committee then discussed
appeared relevant. Each
respect to each criterion.
The criteria the committee used are:
Criteria, Options, and Evaluation
and listed those criteria that
option was then discussed with
Technical feasibility. Can the option be implemented suc-
cessfully from a technical or engineering standpoint?
Long-term reliability. Will the option protect the light-
house for at least 100 years?
Short-term reliability.
house for at least 20 years?
Initial cost.
the option?
Will the option protect the light
What is the approximate cost to implement
Long-term cost. What are the likely recurrent future
costs to maintain the effectiveness of the option?
Protection of natural resources. What are the potential
effects on ecological, hydrological, geomorphological, and
related natural systems and processes in the vicinity of Cape
Hatteras Lighthouse?
Aesthetic impact. What is the visual effect of the option?
Local public considerations. How are residents of the
Outer Banks, specifically Buxton, N.C., likely to view the
option?
Protection of historical values. What is the implication of
the option for preserving the lighthouse, its associated build-
ings, and its historical milieu? Will a precedent be set for
protection of other historic structures similarly endangered?
Public access and recreation. What is the effect of the
option on public enjoyment of the lighthouse site, including
the beach in front of it?
OCR for page 49
Options and Criteria
49
Risk of damage to the lighthouse during implementation.
What is the likelihood of damage to or destruction of the
lighthouse due to or during implementation of the option?
Preservation of other options--short term. To what
extent does the option immediately foreclose alternative pres-
ervation options?
Preservation of other options--Ion" term.
ervation options foreclosed after 20 years?
Are other pres
Construction time. How long will it take to achieve
effective protection after an option is chosen?
Coastal Barrier Resources Act. Although NPS is not
covered by the CBRA, to what extent is the option consistent
with the act?
NPS shoreline-management policies. Is the option consis-
tent with NPS policy not to obstruct natural processes on
coastal barriers?
North Carolina coastal policies. Is the option consistent
with state policy on response to shoreline retreat?
Flood-hazard mitigation.
How does the option relate to
the national goal of reducing flood hazards through adjust-
ment of land use in floodplains, the National Flood Insurance
Act, and Executive Order 11988?
Wetlands effects. What is the
option on wetlands and other U.S.
Section 404 of the Federal Clean Water Act?
potential effect of the
waters regulated under
Fisheries. What are the potential effects of the option on
commercial and recreational fish habitats?
Navigation. How would the option affect commercial and
recreational navigation?
The criteria fit into four general categories. The first
contained crucial criteria: if an option failed to meet these
OCR for page 50
50
Criteria, Options, and Evaluation
criteria, it was not considered further. The crucial criteria
were technical feasibility, short-term reliability, initial and
long-term cost, protection of historical values, and risk of
damage to the lighthouse during implementation.
Options that met the criteria in category 1 then were
considered against criteria in category 2. This category con-
tained important criteria but not so important that failure to
meet one of them automatically excluded an option from fur-
ther consideration. Some of these criteria are relative--
although no option would guarantee protection under all cir-
cumstances, some would offer better protection than others.
All options that would provide at least some protection would
cost a substantial amount of moneY. but some would cost
more than others.
. . . . . . -
~. ~. . . - . ~
~ ,
The criteria in category 2 were long-term
ready, Nag and ~ong-~erm cost, protection of natural
recreation,
lone term.
_
resources, aesthetic impact, public access and
preservation of other options in the short and
construction time, and NPS shoreline-management policies and
North Carolina's coastal policies.
The third category consisted of criteria that overlapped
with one or more in category 2: Coastal Barrier Resources
Acts flood-hazard mitigation, and wetlands effects. Although
these criteria were not identical to any in category 2, every
time the relevant category 2 criteria--i.e., protection of
natural resources and relevant coastal-management policies--
were met, these criteria also were satisfied.
Category 4 contained two criteria that did not appear to
be affected much by any option--fisheries and navigation--
and one criterion, local public considerations, which is impor-
tant to decision makers but outside the committee's purview.
Six options failed criteria in category 1. Deployment of
artificial seagrass is not technically feasible in that it does
not work, and the committee was uncertain of the effective-
bullulng a new light-
nouse would not protect historical values as required by
NPS's mandate. Beach renourishment would incur excessive
long-term costs, and no action or rehabilitation of the groin-
field without a revetment would not provide reliable short-
term protection for the lighthouse.
The committee's evaluations of the remaining four options
were based largely on criteria in category 2 and are dis-
cussed in detail in Chapter 5. In brief, relocation would not
,
. .
ness of artificial reefs at this site.
OCR for page 51
Options and Criteria
51
fail any criterion. The seawall/revetment option would con-
flict with coastal management policies, historic preservation,
long-term cost, public access and recreation, aesthetic con-
siderations, risk of damage during implementation, and pres-
ervation of other options. Rehabilitation of the groinfield
with a revetment and offshore breakwaters with groinfield
rehabilitation would not satisfy criteria concerning long-term
reliability and shoreline management policies.
The types of conflicting considerations faced by the com-
mittee (such as conflicting public policies and the desirability
of minimizing cost while maximizing protection) also might
arise in other NPS decisions regarding historic preservation
and conservation. The committee suggests that an approach
similar to one it used--developing a set of relevant criteria
and studying options against those criteria--would prove use-
ful for other decisions that involve conflicting considerations.
OCR for page 52
OCR for page 53
5
Evaluation of the Options
The committee provides cost estimates for the options
discussed below (except for artificial reefs, for which too
many variables are involved, and artificial seagrass, for which
no effective level of application can be determined). In some
cases, estimates from other sources were used as the basis
for the committee's estimates. In other cases, the committee
developed its own estimates.
The committee's cost estimates are conservative, and
should be considered as guides, within a range of perhaps
+20%. The actual cost of each option can be determined only
by receiving a specific proposal from a contractor. Variables
not included in the committee's cost estimates include com-
petition, experience, expertise and equipment already owned,
and time involved in obtaining necessary permits and insur-
ance.
Several options imply costs of maintenance and repair or
of rebuilding or choosing another option in the future. In
addition, an appropriate discount rate must be applied when
considering future costs.
-
For example, if OMB's current dis-
count rate of 10°h per year is applied, a cost of $5 million 30
years in the future is minor compared with a similar cost
next year. Except in the case of beach nourishment, the
committee did not attempt to account for inflation in future
costs, and all estimates of future costs are in present dollars.
In addition, the committee made no attempt to adjust pre-
vious cost estimates from other sources. Thus, the dollar
values of all previous estimates are valid for the dates of the
estimates.
53
OCR for page 54
54
Criteria, Options, and Evaluation
INCREMENTAL RELOCATION: THE PREFERRED OPTION
Overview
The committee concluded that the best option is to relo-
cate the lighthouse a minimal distance--400-600 feet (122-
183 meters)--to the southwest, which will ensure protection
for approximately 25 years. Thereafter, the lighthouse should
be moved further as advance of the sea requires. Steel
lifting beams for the move would be left in place (concealed
by sand) to facilitate future moves. Subsequent moves would
be less expensive than the first, because much of the work
required need be done only once. * The current groinfield
would not be repaired under this option.
Choice of the initial resting site should be made by NPS;
the committee favors an area close to the southwest corner
of the present parking lot. This and other areas are dis-
cussed under "Site Selection." The committee recognizes that
methods for relocating the lighthouse other than the rail and
track method described below are available. However, based
upon the information currently available to it, the committee
believes this method will minimize cost and
will minimize cost and ecological
damage. Detailed confirmation of the correctness of this
approach and the technical details of any relocation must be
determined by a contractor, retained by NPS. A conceptual
description of the committee's suggestion is outlined below.
In preparation for the move, the building's structure
would be assessed and minor repairs and reinforcements made
as needed. The foundation of the lighthouse would be tun-
neled for insertion of a series of needle beams. Then the
lighthouse (minus part of its below-surface foundation and
The three groins were constructed by the Naval Facilities
Engineering Command to protect the U.S. Navy facility north
of the lighthouse, although the south groin was installed
south of its originally planned location to extend protection
to the lighthouse (U.S. Army Corps of Engineers, 1985~. The
present committee was asked to consider options to protect
the lighthouse, not the Navy facility. If the groins were
maintained, they would probably continue to reduce beach
erosion in front of the Navy facility and the lighthouse.
OCR for page 55
Evaluation of the Options
55
the timber mat) would be vertically raised by hydraulic jacks
to clear the below-surface foundation that remained.
The lighthouse would be lowered onto rollers that rest on
multiple horizontal steel-rail beams supported by precast con-
crete piles. The entire lighthouse structure would be moved
on the tracks with hydraulic jacks and pulled to its new site
,
where it would be placed on a newly constructed foundation,
such as a pile-supported concrete mat (Figure 9~. The total
time estimated for the move, including engineering analyses,
is approximately 1 year; preparation and relocation of the
lighthouse would take fewer than 3 months. The actual relo-
cation should not occur during hurricane seasons--summer
and fall. It is expected that the light will be nonfunctional
during this 3-month period. The keepers' quarters could be
moved using standard housemoving techniques.
Before relocation, the external structure would be
strengthened and reinforced as an integral unit by vertical
and circumferential prestressing as discussed in "Risks to the
Lighthouse," and as shown in Figure 10. The foundation tun-
neling would involve no movement of the tower. Needle
beams would be inserted immediately into 3-foot (91 cm) tun-
nels; thus, the base of the lighthouse would not be weakened.
During lifting, hydraulic jacks would be equipped with
mechanical locknuts, and cribbing would be placed close
behind; this would limit vertical displacement to less than
inch ( 1.3 cm) in case of jack failure. Were a jack to fail,
the center of gravity would move about 11 inches (3.2 cm)
horizontally. The top would move more, but such displace-
ment should have little effect on the stability of the light-
house.
_
~. ~. .
~- - - - - ,
· .
Cost of First Move
The MTMA Associates report ( 1980) described relocation
of the lighthouse in one piece to an area approximately 2,800
feet (850 meters) southwest of the present location at a cost
of $2.7 million. The NPS Environmental Assessment ( 1982)
estimated $5.9 million, and the Move the Lighthouse Commit-
tee (Fischetti et al., 1987) estimated $3.2 million to move the
lighthouse to the same area.
OCR for page 90
90
Criteria, Options, and Evaluation
Beach Nourishment
Sand from nearby sources could be pumped to the beach
in front of the lighthouse. Beach nourishment has been
applied to eroding shorelines north of the lighthouse in
amounts of 312,000 cubic yards (240,000 cubic meters) in
1966, 200,000 cubic yards (153,000 cubic meters) in 1971, and
1.25 million cubic yards (960,000 cubic meters) in 1973
(MTMA Associates, 1980; U.S. Army Corps: of Engineers,
1985~.
Cost
MTMA Associates ~ 1980) estimated an initial cost of $2.9
million to pump 500,000 cubic yards (380,000 cubic meters) of
sand to the beach in front of the lighthouse. Supposing a
need for an additional 300,000 cubic yards (230,000 cubic
meters) every other year and 300,000-500,000 cubic yards
after every major storm, the long-term cost was estimated at
more than $120 million (not discounted) over 100 Years. NPS
~ , ,
(1982) estimated an initial cost of $3 million and a 50-year
cost of $60 million. To nourish the beach with 1,000,000
cubic yards, the committee estimated an initial cost of
approximately $2 million and further estimated that the
maintenance cost--initially about $700,000 per year--would
increase with time. Even applying OMB's discount rate of
10% per year, a maintenance cost of $700,000 per year over
the next 20 years is worth more than $5,000,000 in present
value.
Evaluation
Beach nourishment, achieved by transporting sand from
near Cape Hatteras or from Diamond Shoals, is one techni-
cally feasible response to the erosion problem at the light-
house. This approach -has the merit of requiring no visually
obtrusive structures at the lighthouse except those related to
pumping sand. Furthermore, the sand to be taken for place-
ment at the lighthouse is not needed to maintain a developed
the virtually permanent
.
-
downdrift shoreline.
~i,
~. . .
Nevertheless,
OCR for page 91
Evaluation of the Options
91
pipeline and pumping equipment necessary for the repeated
nourishments would intrude upon the natural setting and
interfere with beach use by visitors to the seashore. ~^
~ ~ 11- sand
were taken from the beach near Cape Hatteras, the huge
borrow pits might interfere with beach access and reduce
nesting sites for birds. However, the benefits of beach
nourishment are short lived. Therefore, large quantities of
new sand must be applied frequently to counteract erosion.
The decisive criterion that this option fails is cost. The
costs of beach nourishment are prohibitive, as described
above, and, as the shoreline continues to retreat, the costs
of maintaining an increasingly large artificial promontory at
the lighthouse would grow disproportionately. Within 50
years, this option may become technically unfeasible as well
as prohibitively costly. Furthermore, this option to control
erosion at the lighthouse does not ensure against loss of the
lighthouse during a major storm.
,, ,
. .
No Action
Although the committee was charged with evaluating
options to preserve the lighthouse, it includes! no action as a
management alternative, consistent with the National Envi-
ronmental Policy Act. No action would lead to loss of the
lighthouse within the next few decades, or possibly sooner, in
the event of a direct hit by a severe hurricane or series of
lesser storms.
The option of doing nothing was eliminated from consid-
eration because it would expose the lighthouse to a high risk
of loss. The lighthouse probably would not be standing today
without the present groin system.
An additional risk is deterioration of the lighthouse foun-
dation if no action is taken. The top of the existing timber
mat is now approximately +2 feet (61 cm) MSL. When the
lighthouse originally was constructed, the fresh groundwater
level was above the top of these timbers, protecting them
from dry rot. As the sea approaches, the groundwater level
will continue to drop closer to MSL, exposing the timbers to
dry rot and the lighthouse to serious settlement and possible
collapse, if it remains in its present location (Lisle, 1985~.
OCR for page 92
92
Criteria, Options, and Evaluation
Because no action probably will lead to loss of the light-
house, this option is not satisfactory.
New Lighthouse
This option was not considered in the interim report. A
new lighthouse would be built a suitable distance inland from
the shoreline. A replica of the present lighthouse would be
one possibility; another would be to hold a design competi-
tion.
Cost
It is impossible to provide a cost estimate for this option,
because the committee could not predict the designs that
would be considered.
Evaluation
Building a new lighthouse would be consistent with the
history of the first lighthouse at this site, which was
destroyed when the present one was built (Holland, 1968~.
When the original 1803 lighthouse at Cape Hatteras became
endangered by the sea in the 1 860s, it was replaced by the
current structure. The original tower was destroyed.
When the present tower appeared to be endangered in
1936, it was abandoned temporarily, and a steel tower was
erected farther inland. When shoreline erosion was reversed
in the 1 940s, the steel tower was abandoned, and the 1870
lighthouse was reactivated.
This option has several advantages. The beach would not
be affected by any new structure, and natural processes
would not be impeded.
lowed. An example would be set for other problems In
coastal-zone management elsewhere, teaching the value of
adapting to ecological forces rather than trying to hold fast
to difficult positions.
However, NPS's purpose is to preserve Cape Hatteras
Lighthouse as required by its mandate to preserve historic
Historical precedent would be fol
~. ~. ~Ha -
OCR for page 93
Evaluation of the Options
93
structures. Construction of a new lighthouse, however
imaginatively designed or built to resemble the original,
would not serve the purpose of historic preservation. Recon-
struction merely suggests the form and materials of the old
structure. To replicate the lighthouse in all its detail, using
original construction methods and materials, would be pro-
hibitively expensive and might not be possible. For this rea-
son, this option does not meet NPS's needs.
OCR for page 94
OCR for page 95
6
Practical Consiclerations
The committee discussed a variety of practical matters
related to moving the lighthouse. Some would apply to any
option chosen by NPS, others are specific to the relocation
option.
CONTRACTING CONSIDERATIONS
Because of the unusual nature of lighthouse relocation and
the intricacies of federal procurement regulations, the com-
mittee believes it prudent to comment on the potential NPS
contracting process. NPS must comply with the Federal
Acquisition Regulations System ( 1987), as well as its own
agency-specific procurement regulations and policies. Within
those constraints, two considerations are of great importance
in this matter:
.
.
The need to select a well-qualified contractor from the
small number of firms technically capable of performing
such a project successfully.
The need to allow appropriate flexibility regarding spe-
cific methods to be used by the contractor to accom-
modate realities such as local availability and cost of
materials, as well as geological, structural, and engi-
neering factors that will be inherent to the methods
employed.
95
OCR for page 96
96
Criteria, Options, and Evaluation
A suitable way to select a contractor is a two-stage,
negotiated procurement process such as that used by the U.S.
Army Corps of Engineers on similarly complex projects
involving potential risk, such as the Wolf Creek Dam cut-off
wall in Kentucky. Offerors would submit qualifications (e.g.,
experience in similar projects, technical and engineering
capabilities, and proposed supervisory staff). NPS would
carefully screen the technical qualifications of potential con-
tractors (with an independent advisory board if necessary)
before specific technical and cost proposals for the actual
work were solicited.
Qualified offerors would provide a detailed technical pro-
posal for carrying out the lighthouse relocation. This would
include the following:
Prepare detailed plans to strengthen the lighthouse to
give it full structural integrity.
Prepare detailed plans for the permanent foundation of
the relocated lighthouse.
Prepare detailed specifications for repairs to the
gallery, lantern, stairs, windows, and masonry coatings.
Prepare detailed plans for moving the lighthouse.
Prepare detailed performance criteria for the move,
including raising the structure, temporary dewatering
and excavation, jacking procedure and controls, allow-
able tilt, allowable accelerations and restrictions on
jerk, control during the horizontal move, and final set
down.
With the advice of a board of consultants (and an inde-
pendent engineering consultant with structural and geological
expertise), NPS would review all submitted materials and
select qualified contractors and request a financial proposal.
NPS would be permitted to suggest minor modifications in
any offeror's technical plans. Selected contractors would
submit competitive cost proposals for the total project, which
would include assumption of responsibility, and an appropriate
insurance policy.
OCR for page 97
Practical Considerations
97
Allowing flexibility in methods to be used implies the need
to develop and specify performance criteria for the light-
house relocation--rather than detailed methodological require-
ments--in the NPS request for proposals. The committee
emphasizes that no set of detailed methocls, including the
committee's own example of a relocation concept, should be
specified at the outset. Rather, performance criteria, such as
the desired lighthouse site location, structural and architec-
tural rehabilitation and strengthening, measurable damage
limitations, allowable displacement of structural components,
and other criteria suggested above are preferable for this
type of project.
INSURANCE
Builder's risk insurance is available to cover any physical
damage to a structure that results from external events, such
as tornadoes and hurricanes during the contract period.
Insurance also is available to cover contractor's errors or
omissions. Maximum coverage would be limited to replace-
ment value of the structure.
Professional liability insurance is available to protect the
relocation contractor and the engineering consultant from
errors in design or specifications, including omissions. Limits
are specified, but usually have a maximum of $5,000,000.
Project wrap-up insurance can be obtained on a case-by-
case basis, which includes the professional liability of all
parties involved in design. An insurance company usually
will insist on an independent review.
INTERIM MEASURES
The committee was asked to comment on interim measures
for protecting the lighthouse. Such measures should be taken
as soon as possible to reduce the possibility of damage or
destruction of the lighthouse before long-term protective
measures can be completed. However, no interim measure
would provide enough protection to justify postponement of a
long-term solution.
OCR for page 98
98
Criteria, Options, and Evaluation
The immediate danger to the lighthouse is the destructive
erosion that might occur during a single storm or series of
storms, rather than gradual, long-term retreat of the beach.
A storm or storms might occur at any time of year, and
would provide at most a few days' warning of their arrival.
The most cost-effective interim measure--and one that
could be implemented quickly--is beach nourishment in the
bight immediately south of the southernmost groin. The
~ ~ ~ e ~ ~ ~ ^~^ ___ ~ _ (9 1 0
meters' ot neacn south of the southernmost groin. This
would require a volume of sand 3 yards (2.7 meters) deep and
40 yards (37 meters) wide, totalling 120,000 cubic yards
(92,000 cubic meters). The estimated cost of pumping this
quantity of sand from the vicinity of Cape Point is $530,000.
It should be recognized that this measure would be sacrifi-
cial--the new sand would be lost in a major storm. But its
purpose would be served if it buys enough time to implement
a long-term protective option.
committee suggests adding sand along Mu varos
REHABILITATION OF THE LIGHTHOUSE
. . ~. ,~.
Constructed of mass brick masonry, the lighthouse is
structurally sound. However, long vertical cracks are evident
in the interior brick wall on the north and south sides of
the lighthouse from the first landing level to the sixth land-
ing level, extending intermittently for 150 feet (46 meters).
These cracks pass through many points where stair stringers
are anchored to the wall and through the sections that con-
tain the window openings.
Thermal effects probably caused these long cracks. When
the outer cylindrical masonry wall of the lighthouse expands,
high tensile stresses are induced in the inner cylindrical wall,
because the two are tied together by a series of large, brick
ribs. Cracks would be expected to occur in the interior wall
along its weakest vertical sections. Movement of these
cracks under thermal changes was confirmed by field instru-
mentation measurements.
Additional cracks also have been observed at various loca-
tions where metal attachments are fastened to the interior
wall. These cracks likely have developed as the result of
corrosion of the anchorage for the attachments.
_ . . . . . ~
OCR for page 99
Practical Considerations
99
Although these cracks do not adversely affect the struc-
tural integrity of the lighthouse, the committee recommended
that they be cleaned and sealed with a high quality, flexible
joint sealant to prevent further deterioration and intrusion of
moisture into the wall. These necessary rehabilitation efforts
and other preservation measures have been thoroughly
defined by an architect/engineer team (Hasbrouck Hunderman
Architects et al., 1986) and should be implemented as soon as
feasible, regardless of the option chosen for long-term pro-
tection of the lighthouse.
The committee hopes it will be possible to open the light-
house to public access on completion of relocation or other
long-term protective measures.
SITE DESIGN
Before the lighthouse is moved, the future location of the
dwellings and other structures that form the lighthouse com-
plex must be considered carefully. It would be best to place
these structures at the new lighthouse site so that their
physical relationship to the tower will continue as it has
been in the original location.
The present visitor parking and picnic areas impinge on
the historical setting of the lighthouse. The committee
suggests that additional parking and other visitor facilities
should be separated from the lighthouse complex and
screened by natural vegetation. Every effort should be made
to recreate the sense of isolation of the original 1870 light-
house setting.
OCR for page 100
Representative terms from entire chapter:
beach nourishment
