VI BEHAVIORAL RESPONSES TO FLOODS

Various institutional mechanisms have been available to cope with
flooding. To evaluate their effectiveness, it is necessary to understand
how individuals and groups, organizations and communities, respond to
information on flooding in pre- and post-disaster periods.

Research findings show several responses to flood events. From these
data, a model of choice emerges depicting the human decision making
process regarding such low probability events. Use of the model enables
critical evaluation of alternative approaches to risk assessment and
provides a context for interpreting public issues pertaining to flood
mitigation.

Individual and Group Responses to Flood Events

Field studies over the past 30 years have revealed much about the
behavior of individuals and groups confronting flood hazards.
Significant conclusions can be summarized within four topics: warning
responses, emergency period behavior, long-term impacts, and key
variations in model responses.

Several empirical studies have provided some basic foundations for a
knowledge base to inform policy makers on the physical aspects of
flooding, but relatively little research has been funded to ascertain
the complex human responses evoked. Reflecting minimal funding
priorities, most of the research completed has been constrained severely
in design, measurement, and sampling adequacies. Quality of the present
knowledge base is deficient: almost no comparative studies exist wherein
several events with different characteristics and locations might be
juxtaposed with common sets of measurement instruments; and there is a
scarcity of longitudinal data whereby the dynamics of change might be
monitored. These deficiencies and others have been highlighted
previously, and in recent years a few exemplary studies have received
funding. Guidance for future policy requires that human responses to
flood hazards receive a much higher priority within research
allocations. Such studies will improve our knowledge base of human
responses to low probability events, including floods.^1^

Warning Responses

Despite the near universal presence of telephones, radios, and
television sets whereby public information can be disseminated rapidly,
lives continue to be lost because of inadequate flood warning Systems.
Behavioral research studies have documented well the incorrectness of
the stereotype of mass panic upon issuance of riverine flood or
hurricane warnings. Indeed, quite the opposite type of response occurs:
general disbelief in the warning. If subsequent messages are received,
or if the first one has adequate precision, then some effort may be made
to confirm the threat information. Typically, relatives, friends, or
neighbors are consulted, and a few persons will turn to official
sources. Contradictory information frequently is obtained through the
media during this confirmation period. Often, this neutralizes urgings
of evacuation received from other sources.

Even if individuals gradually define a flood threat with reasonable
certainty and conclude that they might be at risk, they still must have
a plan of adaptive action.

When individuals do evacuate in response to warnings, they usually
respond as family units. If family members are physically separated when
warnings are issued, they will delay evacuation and seek to establish
rendezvous locations so that the family can be united upon relocating.

Much remains to be learned about responses to flood warnings, but the
current knowledge base does highlight a key policy concern.

Given existing technologies and scientific understanding, the time has
come to ask, \"Why don\'t local officials issue flood warnings which
elicit the desired evacuation behavior?\" With this in mind, failures in
the existing warning systems, especially the limited capacity of most
local units to evaluate and disseminate flood threat information, become
highlighted. A key research priority should be to improve understanding
of constraints and incentives related to the implementation of response
Systems based on what is known about human behavior.

Emergency Period Behavior

At the time of impact and shortly thereafter, field descriptions reveal
an imagery of \"organized-disorganization. That is, behavior is highly
organized when one looks at a single individual or the small groups
within which they operate, such as in families or work groups. These
independent actions typically are not well coordinated, and disaster
scenes have an appearance of mass disorganization.

A major reason for this response pattern is that in emergencies people
act. They do not wait for officials to tell them what to do. With
resiliency and resourcefulness, they initially ascertain the safety of
family members and take protective action. Once that priority is met,
victims will seek to help neighbors and friends. Strangers encountered
may receive a helping hand, too.

These behaviors are augmented by those outside the impact area.
Organized groups of emergency officials and volunteer units rapidly
mobilize and converge at the disaster site. Often motivated by dual
incentives of providing help and satisfying their own curiosity, these
rather small groups of volunteers often aggravate the demands on the
formal emergency organizational network. Rather than being recognized as
an available resource, they may be defined as a problem source. At times
this even can be true of highly skilled volunteer search and rescue
units, GB radio groups, and others who could greatly augment the
resource base of the response system. Despite such curtailments and the
typical duplications which fragmented responses produce, most flood
victims, like disaster victims generally, experience an intense
emotional impact. There is a consistent pattern of initially
underestimating the enormity of the devastation. When the consequences
are grasped, mental trauma intensifies gradually as the requirements of
restructuring and adapting to temporary lifestyles clarify. Mild
emotional upset will be experienced by many, but recent evidence
indicates that severe and lasting negative mental health impacts are
much less than had been thought previously.

Repeated offers of help come from relatives, friends, and numerous
agencies. Some persons are helped sooner and to a greater extent than
others; for example, the elderly may be neglected. Most victims
participate actively in a post-disaster theraputic community in which
emergent helping networks restore material losses and provide emotional
support. Unfortunately, enthusiasm of the helpers often wanes prior to
completion of clean-up and short-term recovery. Persons associated with
bureaucratic units responsible for continuing the operation, such as the
Red Gross, insurance companies and federal assistance agencies, may
become targets for pent-up emotions and fatigue. Delays by local
decision makers, especially delays on rebuilding plans, may foster a
climate of uncertainty which provokes these emotions and the hostility
they produce.^1^

Long-term Impacts

Responses during the warning and emergency phases of flood events have
been studied, but relatively little research has been conducted on
longer term impacts. Some evidence pertaining to macro-systems, such as
communities, suggests that disasters generally have little impact on
long-term economic recovery processes. This issue is complex, and data
analyzed are highly selective and subject to differing interpretations.

Serious and continuing adverse mental health consequences have been
documented following a savage flash flood in Buffalo Creek, West
Virginia. Critics have raised many issues with this study, and results
are not consistent with those from other flash floods such as at Rapid
City or those produced by hurricanes like Agnes.

Consistent with the Rapid City data are several studies of tornado
responses which may be applicable: Topeka, Kansas, 1966; Xenia, Ohio,
1974; and Omaha, Nebraska, 1975. These data indicate that two and three
years after a disaster, victims have a sense of well being which is very
similar to their pre-event state, but their primary group involvements
are altered slightly. Bonds to kin and friends are tightened and
relatives, especially, are now perceived as important help sources
should future adversity occur.

One study indicates that linkages to neighbors are weakened and
participation is most voluntary associations decreases slightly, with
one exception. Victims report more commitment to and involvement in
their churches during the years afterwards. Limited evidence thus
indicates growth of closer bonds with those elements of the theraputic
community response through which recovery occurred. Available evidence
strongly suggests that there may be different impacts on various other
groups.

Key Variations in Model Responses

Although the above response patterns have been studied, other important
variations have yet to be investigated adequately. For example, urban
responses seem to reflect less primary group involvement than do rural
responses in areas where fewer formal organizational resources exist. To
be effective, policy pertaining to all phases and locations of disaster
response may need to vary. Distinctive disaster sub-cultures have been
documented in regions confronting repeated flooding, be they river
valleys or hurricane prone coastal areas. These community based
expectation patterns structure more adaptive responses during flood
emergencies but also appear to neutralize somewhat the sense of future
risk. This may encourage resettlement and even further development of
the floodplain.

Impacts of flooding may be more acute for some population sub-groups.
Evidence from Rapid City, for example, indicated that disproportionate
numbers of the elderly died. Evacuation difficulties of handicapped
individuals involving fire hazards may be duplicated regarding flood
responses. Similarly, reflecting greater isolation from primary groups
who might buttress official warnings and aid in recovery, the elderly
and some ethnic minorities may not experience the positive effects of
participation in the theraputic community response to the same degree
that the general population does.

As the discrepancy in findings on mental health impacts indicates, flood
events differ in many qualities which may produce alternative types of
impacts. Typically, flash floods precipitate far more horrifying
experiences for victims than do those with slower speeds of onset.
Floods striking communities with minimal social integration and economic
resources for recovery, compared with floods striking highly integrated
communities, may be far more devastating to the social forces which bond
individuals together and provide for stability in individual identity
and performance.^6^ Comparative research designed to isolate and
systematically investigate these and other types of response differences
is in its most embryonic form today. National assessments of short-term
and long-term impacts of public and private flood relief programs for
families victimized should be completed. Such research should be given
priority in the coming decade.

Organizational and Community System Responses

Field and laboratory studies of the responses of organizational managers
to various types of crises, including flood events, provide a research
base that needs far greater dissemination, especially among those
responsible for flood mitigation in local
communities.^1^\'^3^\'^8^\'^10\ ^Unfortunately, too often, disciplinary
differences in emphases and terminologies make it very difficult to
integrate such insights. Encompassing several disciplines, key research
findings can include three themes: system response to stress events,
coping adjustment, and decision criteria and processes.

System Response to Stress Events

Numerous case studies describing community and organizations responses
to a wide variety of natural and manmade catastrophes document the
relatively decentralized structure of American society. Although state
and federal agencies provide critical resources, the major actions,
especially initially, are produced by local community organizations.
Typically\--although some exceptions have been identified, especially in
areas confronting reoccurring events like hurricanes\--these responses
are fragmented and not well coordinated. In part~\ ~this reflects the
relatively high degree of autonomy which each local organization enjoys.
Floods, especially those with rapid onset, create a set of demands which
are beyond the resource capabilities of any single unit. A different
type of interorganizational system is required to effectively meet these
demands, one which recognizes the heightened interdependence among the
responding units.^1^

Gradually some type of coordinating scheme emerges, although typically
in an ad hoc manner and with at least some wasted motion. Afterwards,
communication problems\" often are blamed as the barrier. This may be
accurate. Although each independent organization may have ample
equipment to monitor and adjust the actions of its own personnel,
frequently inadequate means exist to facilitate a regularized flow of
information across the organizations. Hence, their respective actions
and decision processes cannot be integrated into a unified response.
Structurally, local emergency operations centers could perform this
critical function, and some do. Field work continues to document the
lack of full realization by local officials that such demands constitute
a unique managerial problem requiring an organizational design which
differs from day-to-day operations.

Consequently, key decisions made within one sector of the community may
not be communicated to another at the appropriate time. Certain groups,
often hospitals, may not be alerted immediately, thus hindering their
mobilization. The specifics vary from case to case. The fundamental
principle which emerges is that large scale disasters produce sets of
demands that require far greater levels of coordination than most local
organizational managers have experienced. Constructing mechanisms for
crossagency communications is only the first step. A multiorganizational
command center is required wherein community needs can be assessed
rapidly, and group decisions can be implemented rapidly. A far more
centralized multiorganizational decision structure is required than
exists normally.^3^\'^10^

Adding to the complexity of this managerial design problem is the need
for better coordination with various extra-local organizations that
request information and offer assistance. Too often, these state and
federal actions further compound the volume of information requiring
processing. Also, local news media may lack information but must respond
to inquiries from regional and national networks seeking to make program
decisions within a very limited time.

The net result is an enormous informational processing task which
quickly overloads each individual response system, even if all their
communication equipment remains operational, which is rare. Telephone
systems become overloaded quickly and are especially vulnerable.
Clusters of managers must confront a morass: lack of needed information
for field decisions requiring immediate action, and inadequate
procedures for consultation across the respective units. Many decisions
are made in an informational vacuum without adequate knowledge of what
others are planning or doing. Too often, the emergence of more
centralized multiorganizational decision mechanisms become stabilized
only after emergency demands have been met.

Local communities exhibit remarkable resiliency and resourcefulness in
conquering such stress situations. Most officials come out of it with a
renewed sense of community pride, and like individual victims, with
appreciation for the massive resources made available. Cooperation, even
among old enemies, is the quality remembered. The trauma, which might
have been experienced temporarily when confusion abounded and the crisis
seemed only to be getting worse, dims rather quickly. Only a perceptive
few seem to grasp the inherent deficiency in their pluralistic system
and how it was transformed temporarily to meet the stress of disaster.

Coping Adjustments

Within this general context various short-term adaptations are more
readily understood. For example, regardless of the organizational
function or the degree of centralization of its communication and
decision system, more decisions are made at lower levels. Fewer
individuals are consulted prior to field units taking actions, and
communication patterns shift to maximize speed and efficiency.
Simultaneous with the gradual adaptation toward a more centralized
structure at the community level, local organizations reflect increased
decentralization tendencies. Temporarily, autonomy at the top decreases,
and those at lower levels are required to make more decisions.

As these actions occur, additional demands are identified which do not
fit within the usual task pattern of the various local organizations or
greatly exceed the capacity of those who might be expected to take on
the task. For example, following the 1976 Big Thompson Canyon flash
flood in Colorado, the local coroner was confronted with an enormous
task of body identification which was complicated severely since no one
knew the exact number of persons scattered throughout the canyon.
Inquiries from throughout the United States were received regarding the
safety of relatives and friends, which produced a unique information
processing demand for county officials.

In such situations, local organizations expand their resource base with
personnel and equipment from other agencies. Authorization of their use
or organization rarely has been preplanned. Under conditions of stress,
field personnel will form emergent groups and many actions are handled
informally since existing authority bases may not be applicable or fully
known by all responding.

After the crisis period, local officials are introduced to community
relief and rehabilitation options through state and federal programs.
When a Presidential Declaration is made, wide ranging alternatives of
individual family and public assistance are available. These resources
greatly expand the community capacity for recovery, but local officials
then confront many reconstruction issues which also must be decided
within a relatively short time.

Even short delays typically are met with mounting citizen pressure.
\"When can we return home?\" becomes translated quickly into \"When can
we begin repairs and rebuilding?\" Local officials are operating within
a context of intense public sentiment. Too often, more detached analyses
of floodplain management fail to recognize the intensity of the public
desire for a return to normalcy. This social reality is as much a
constraint on local officials, who must make the hard decisions of
reconstruction, as are the engineering analyses documenting how the
floodplain may have been inundated.

Decision Criteria and Processes

Local officials, like their counterparts at the federal level, can
articulate a broad set of decision criteria to guide flood mitigation
policy. Although the language varies with the locale, five major goals
would emerge on most lists: reduction in net losses to property,
reduction of casualties, avoidance of social disruption, protection of
the natural environment, and more equitable distribution of costs and
benefits.^12^

These broad criteria can provide only general guidelines. There is no
quantifiable decision system wherein selected data sets can be
formulated to specify \"the best\" decision. When officials seek to
apply these five criteria they confront difficult choices as to the
relative merits of one against the other. Value judgments enter the
process at each step of the way, and there is much uncertainty inherent
in the anticipated outcomes. Recent analyses have greatly improved the
understanding of the complexity of such analytical problems, but a
machine-like decision tool for flood mitigation policy selection does
not exist. Within a society which is decentralized structurally and
highly pluralistic in its value pattern, the policy decision making
process will remain highly complex, an art of political strategy which
has to be coupled with the tools of decision making.

Alternative consequences of decisions can be displayed much better so
that local officials can act in a more informed manner. Recent studies
have only begun to explore the dynamics of post disaster community
decision making and disaster policy formulation. Decision makers display
some rationality, but their behavior rarely is entirely systematic. It
is questionable how well they follow these steps: appraise the
probability and magnitude of extreme events, canvass alternative
actions, seek to evaluate consequences of selected actions, and make
conscious choices for a course of action.

Although the sequence of these behaviors is not uniform, there is some
ordering; but the pattern is variable and complex. Descriptive studies
also indicate that organizational managers assess policy proposals
regarding possible consequences for the autonomy, security, and prestige
of their units. These values are important augmentations in almost any
decision process as it occurs behaviorally.

Process of community decision making regarding flood mitigation are not
now well understood, but one study has identified six broad questions to
guide post-disaster reconstruction: should normal, as contrasted to
extraordinary, decision making mechanisms be used in deciding how, when,
and where to rebuild a heavily damaged city?; should there be changes in
land-use?; should building codes be changed?; should special financial
assistance for private property losses be provided?; and how should
disaster-produced family problems be handled? Contingency planning
focused on these questions, and for future planning, the necessary
informational inputs should be recommended to all local officials.^9^

The social reality local officials confront has been documented in a
recent survey which indicated that hazard mitigation ranks relatively
low in priority. Within a highly competitive mix of community issues,
including crime and inflation, flood mitigation ranks rather low. It has
the distinctive disadvantage of being subject to mechanisms of denial
because of the catastrophic consequences. Thus, paralleling the
processes of flood warning responses, among the public at large,
community officials can more easily delay policy reevaluation and action
regarding hazard mitigation, especially if they are confronted regularly
with vocal special interest groups. Rarely do public demonstrations
focus on flood mitigation matters. Indeed, public awareness seems
minimal except during and shortly after a flood event. Given the
typically hectic daily routine of most managers of local organizations,
long-range floodplain planning and emergency preparedness will not be
considered unless some source provides a stimulus.

A recently completed survey of 1415 jurisdictions across the United
States revealed that stronger programs of land-use management exist in
communities where the probability of experiencing flood damage is
greater than average and this and other floodplain problems are
recognized, this approach has been used before, and financial resources
had been available to mount a vigorous floodplain management effort.
Impacts of these programs vary significantly with changing community
characteristics, but floodplain invasion seems to be determined by local
community characteristics and is not generally affected by these
programs. Although reasonably effective in protecting future development
from flood damage, the regular phase of NFIP less adequately protects
natural values associated with undeveloped floodplains. As implemented
in most places today, floodplain land-use management is not effectively
reducing the flood hazard stemming from existing urban development.

In summary, stimulus for local action must occur and this must emanate
largely from the federal level where flood hazards are regularly
visible; and federal policy should seek to maximize opportunities for
improved flood mitigation efforts within a short time after actual
events, when local awareness of the risk is at its maximum level.

Decision Processes Toward Low Probability Events

Prior to a disaster there usually is lack of preparation for the
consequences of the event, as evidenced by inadequate warning systems in
many communities. Following the disaster the general concern is with
restoring victims and the community to normal activity as quickly as
possible. People respond to the crisis at all levels, from the
individual and family through different governmental units.

A sequential model of choice characterizes the decision processes of
different groups to low probability events such as natural disasters.
Empirical evidence on behavior in the pre- and post-disaster periods
illustrates the applicability of this choice model relative to the flood
problem. These data, coupled with the descriptive findings in the
previous sections of this chapter, raise questions to be dealt with in
the following sections as to how one should evaluate alternative
measures for dealing with flood associated risks.

Sequential Model of Choice

Empirical data from studies of natural hazards suggest the adoption of a
sequential model of choice as shown in Figure 7. Time constraints facing
individuals and organizations frequently force them to restrict their
attention to situations which they perceive to be serious problems
(Stage 1). Even if the flood hazard is perceived to be a serious
problem, there may be only a limited set of options which the
individual, organization, or community may feel is appropriate for
consideration (Stage 2). These options may be a subset of all possible
adjustments, either because of limited knowledge as to what is available
or because of a conscious choice by the relevant group to limit its
considerations to a manageable number. In the final stage of the process
a decision is made as to what options, if any, are attractive for coping
with the flood problem (Stage 3). Here simplified rules for evaluating
alternatives are ordinarily utilized.

Several factors influence each stage of the process. In Stage 1, the
situation in the post-disaster period is considered to be a problem if
it has caused sufficient damage to concern the affected individual or
group. The severity of the problem may be evaluated differently by the
disaster victim who suffers large losses and by the community in which
damage may appear to be relatively minor. At the pre-disaster level, the
situation differs because it involves preparation for an event whose
chance of occurrence in the near future may be relatively low. Past
experience is an important guide to action, and reliance on concrete
data may bias an individual\'s estimate of the probability of future
occurrence of the event.

If the event has occurred recently, people tend to overestimate its
chance of occurrence in the future and feel it is a problem worthy of
attention and possible action. If it has not occurred recently, most
people tend to view its future likelihood as being sufficiently small
that it is not worth worrying about. In the latter case, Figure 7
indicates that no measures would be considered.

In Stage 2, most measures are considered by observing or learning from
others.^17^ When disasters occur, people usually rely on friends and
neighbors for information. Most organizations consider specific measures
by learning from others. This process does not preclude innovation by
individuals or groups. A set of leaders may initiate a new measure by
considering and implementing it to determine its effectiveness. Others
are then in a position to imitate the action if they wish.

In Stage 3, individuals and organizations utilize simplified decision
rules in determining what action to take regarding a particular hazard.
With the exception of structural measures such as flood control works,
the adoption of most actions is not based on detailed benefit/cost
analysis. Instead, a measure will be chosen because it satisfies a need
or a specific goal. Individuals and organizations usually search for
satisfactory, not optimal, solutions to problems.

Illustrative Examples

The sequential model of choice is illustrated by two examples:
protective behavior by individuals in the pre-disaster period, such as
insurance purchase, and passage of relief measures by the federal
government in the post-disaster period.

Empirical data from field studies on flood prone communities throughout
the U.S. reveal that most residents in hazard prone areas have limited
knowledge of alternative mitigation measures to protect themselves
against the consequences of natural disasters. Individuals are reluctant
to collect information on possible adjustments related to natural
hazards because they have other things on their minds, and these low
probability events are not likely to receive attention. Those who
consider protective measures, such as insurance or floodproofing, do so
because they view the hazard as a serious problem (Stage 1). The field
survey data clearly indicate that past experience with flooding was the
most significant factor in alerting home-owners to the seriousness of
the hazard. A much larger proportion of policyholders than
non-policy-holders had discussed insurance purchase with a friend,
neighbor, or relative (Stage 2). Similar proportions exist between
insured and uninsured homeowners who knew someone who had purchased a
policy. These findings are similar to those concerning sources of
knowledge regarding flood warnings.

Finally, individuals utilize simplified decision rules even if they are
given information on the probability and loss associated with a hazard
and the cost of protecting themselves against the event (Stage 3)\~l5
Coverage is demanded when the probability of a loss is above a given
threshold level, in contrast to the individual deciding whether to buy
insurance using benefit/cost analysis. Particularly striking about these
results was the lack of interest in insurance protection when there was
a relatively low probability (e.g., 1 in 100) of a disaster and
relatively large loss (e.g., 1000). Rather, insurance was more
frequently demanded when the probability of a disaster was relatively
high (e.g. 1 in 10) and the loss low (e.g., l0).

The above findings on the relevance of a sequential model of choice
suggest that priority be given to research that determines how
information presented in different forms affects decisions. The findings
also raise questions on how well people understand the concept of
probability and what methods they utilize in assessing risk. Results
from this kind of research can help to suggest programs that are likely
to reduce flood losses by inducing individuals to protect themselves
voluntarily.

Turning now to the second illustrative example, legislation in recent
years indicates the increasing role of the federal government in
providing disaster relief. The Small Business Administration (SBA) is
the primary agency making disaster loans \"restoring a victim\'s home or
business property as nearly as possible to its pre-disaster condition.\"
Before the 1964 Alaska earthquake, the SBA provided 3 percent interest
loans with a maximum repayment of 20 years to cover the exact amount of
physical damage.

Beginning with the Alaska earthquake and continuing through a series of
disasters culminating in Tropical Storm Agnes in 1972 the SBA continued
to liberalize its disaster loan program in response to a set of
perceived needs. The changes in legislation were triggered because
Congress felt that without additional relief the disaster would cause
special recovery problems for victims (Stage 1). Rather than revamping
legislation to aid groups who may have needed special relief, such as
low-income or elderly victims, Congress focused on previous legislation
(Stage 2). Rather than innovating, they modified existing bills to
satisfy specific needs (Stage 3). There was no attempt to evaluate the
costs and benefits of alternative disaster relief measures.

These two examples illustrate the dilemma facing society in developing
future disaster policy. If the current situation continues in which
people do not protect themselves voluntarily against the consequences of
low probability events then society is likely to bear a large portion of
the costs of a disaster. For example, few residents in communities
struck by Tropical Storm Agnes had purchased flood insurance; hence,
there was considerable pressure placed on the federal government to
provide special relief. Congress then responded by forgiving the first
\$5000 of each loan and providing 1 percent interest rates on the
remaining portion. Particularly interesting about this situation is that
over two-thirds of the residents of hazard prone areas, whether insured
on uninsured, feel that the federal government should pay for little or
none of the losses suffered from a future disaster. Also, most residents
have little knowledge of the SEA loan program and do not expect any
relief if they suffer uninsured losses.

Although many victims have taken advantage of liberal government relief
following a disaster, some individuals are reluctant to incur large
debts even though the interest rate is low. It is well known that
elderly residents in Wilkes Barre preferred not to take advantage of the
1 percent interest loans because they wanted to die solvent. Some
uninsured victims who took large SBA loans have been financially
crippled because they were burdened with several post-disaster debts.

To develop meaningful approaches to coping with the flood problem, there
must be awareness of the decision processes of individuals and groups
both in the pre- and post-disaster period. Also, there is need to
recognize the interaction between these two phases in formulating a
meaningful disaster mitigation program.

Note: For references cited, see table following Chapter VII.

VII ASSESSMENT STRATEGIES FOR PUBLIC POLICIES

Introduction

To cope effectively with flood problems, there must be awareness of the
behavioral responses of individuals, groups, and organizations in the
pre- and post-disaster periods. There are alternative methods for
developing and evaluating flood mitigation and recovery strategies. The
flood hazard is representative of a class of low probability events in
which alternative approaches must recognize the limitations of
individuals and groups to collect and process information. Methodologies
discussed include a set of economic, legal, public health, and
statistical issues which are at the cutting edge of flood mitigation
policy analysis.

Uncertainty and Risk Assessment

Flood mitigation programs can rely on a combination of four approaches.
They can utilize a market system in which information is provided to
residents who have the free choice of making decisions. For example,
floodproofing techniques can be offered to residents by the private
sector. A program can utilize incentive systems which promote or
discourage certain policies or developments; for example, a government
subsidized flood insurance program. Alternatively, the government can
impose regulatory measures to control development, such as land-use
measures. Finally, the government can provide projects or services for
alleviating potential damage. Flood control projects are classic
examples of this type of project; warning systems are also illustrative
of information which the public sector provides to flood prone areas.

Any floodplain management measure or combination of measures will impact
on a number of different stakeholders. Not only are the residents and
businesses of the floodplain directly or indirectly affected, but so are
the general taxpayers who have to pay part of the disaster bill.

Businesses and industrial concerns such as the insurance industry,
financial institutions, and the construction and real estate industry
also are impacted by hazard mitigation and recovery programs. Similarly,
state, local, and federal agencies concerned with hazards have a stake
in any policy.

Strategy-Stakeholder Interaction

Figure 8 illustrates the interaction among adjustments and stakeholders
who are affected by particular measures. The first four rows represent
alternatives for dealing with the flood problems. The remaining items
are the more realistic options, a combination of several approaches to
floodplain management. For example, a strategy could be a set of
specific measures such as those comprising the National Flood Insurance
Program coupled with flood control works. Each column lists the set of
stakeholders who are affected by a particular strategy.

The cells in the matrix can be used to indicate costs and benefits of
any strategy. For example, a strategy of subsidized flood insurance
would involve costs: to floodplain residents and businesses in premium
payments and benefits to victims in the form of claims; costs to the
general taxpayer in subsidies; and costs to private industry, such as
insurance agents, and government agencies, such as FEMA, in
administrative costs. This strategy could affect development of the
floodplain which also would have to be considered. Costs and benefits
will depend on the type of flooding and the nature of the flood prone
areas. Each strategy will yield a different set of costs and benefits
which must be specified.

The challenge in developing a meaningful floodplain management program
is to evaluate data entered in the various cells in the matrix shown in
Figure 8 and utilize criteria for selecting among them. This action is
termed the policy evaluation phase which tries to determine the impact
of alternative policies on different constituencies: the flood victim,
the general taxpayer, and businesses and government agencies involved in
hazard mitigation and recovery. The relative merits of alternative
policies are reflected in two types of considerations.

Resource Allocation Costs - These costs are likely to be incurred if
homeowners and businesses located in a flood prone region have
misperceptions of potential consequences from future disasters and ways
they can protect themselves. Recent empirical evidence on natural
hazards suggests that individuals have these misperceptions. Many
newcomers are unaware of the potential damage they face because they are
given little information from knowledgeable sources such as real estate
brokers or homebuilders. Once settled, they tend to assume that a flood
will not occur during their lifetime. In evaluating the impact of
alternative programs \-- such as required insurance, land-use
regulations, and building codes \-- on resource allocation, policy
makers need to understand how individuals collect and process
information.

Distributional Inputs - This feature represents the relative financial
burdens to the flood victims and the rest of society. Governmental
policy implies some value judgment as to what subsidies will be paid by
the general taxpayer and what by the residents of hazard prone areas.

For example, if liberal relief is provided to flood victims and few of
these individuals are insured, then this implies that recovery is viewed
as a public responsibility. Similarly, if flood control projects are
financed primarily by the federal government, then hazard mitigation is
also considered largely a public concern. Within the community itself
there are distributional questions concerning differences in treatment
received by high-income victims and low-income individuals. For example,
if the SBA loan program offered special assistance to uninsured victims
whose annual income was below a given level, then this would have
different distributional consequences than if everyone were subject to
the same relief measures.

The normal starting point for the policy evaluation phase is to
determine how well the market system performs in allocating resources
among different groups Under such a free-choice system, residents of the
floodplain would be in charge of their own destiny. If they chose to
protect themselves they could do so; if not, they would have to bear the
consequences of disaster. What relief they received would be provided
solely by nongovernment funded resources such as the Red Cross, church
groups, friends and relations.

The government becomes involved for several reasons:

\(1\) Certain services such as those provided by flood control projects
benefit many individuals, but there is no incentive for any single
person to pay for them. This kind of public good will be provided by
government or not provided at all.

\(2\) Individuals misprocess information on the consequences of the
event. Government then comes to the rescue after a disaster. As an
alternative, the government may desire to induce hazard prone residents
to protect themselves by providing them with incentive systems or by
regulating the event.

\(3\) The market system does not distribute resources among individuals
equitably. In this case, government may want to redistribute wealth or
income to certain groups such as low-income or elderly residents.

Analyzing Governmental Involvement

To analyze government^s^ involvement in flood program management, the
following topics will be considered: benefit/cost analysis;
multiobjective planning; risk/benefit assessment; and decision support
systems, a recently developed method to assess potential flood
management strategies wherein the boundaries between policy makers and
research scientists are defined more explicitly.

Traditional Benefit/Cost Analysis

Benefit/cost analysis systematically incorporates benefits and costs of
various public projects.

In authorizing comprehensive flood control studies throughout the United
States, the 1936 Flood Control Act (PL 74-738) stipulated that benefits
created, to whomsoever they accrue, must exceed the project costs.
Through the years, this was interpreted as requiring that the ratio of
all expected tangible (monetary) benefits on an average annual basis,
such as prevention of damage to structures, must exceed the annual
amortized first cost of the project plus annual maintenance and
operation costs. Intangible benefits and costs such as social and
environmental impacts were recognized and sometimes discussed in project
reports but not evaluated in monetary terms and, therefore, not included
in the benefit/cost ratio that must be 1.0 or greater for project
justification.

A relevant consideration in analyzing any project is the choice of an
appropriate discount rate for comparing future streams of benefits and
costs. In amortizing first costs or capitalizing benefits and
maintenance and operation costs, an interest or discount rate equal to
the interest rate paid on long-term government obligations was initially
adopted by the Federal government. In 1968 a rate annually revised and
based upon the current yield on long-term government obligations was
adopted and continued in use today. This discount rate policy gives no
consideration to rates of return on alternative investment opportunities
or to the effects of inflation, two considerations which would have
opposing effects on the benefit/cost ratios. Rather than trying to
pinpoint a specific discount rate, it could be useful to determine over
what range or discount values there is no difference in preferences
among projects. If a particular project is favored over a wide range of
values between the market and riskless rate, then there is little reason
to be concerned with the choice of a specific value.

The benefits from the proposed projects were also determined as if
individuals on the floodplain were \"willing to pay\'^1\ ^the expected
value associated with damage reduction from a flood control project. If
they are willing to pay even more than this amount because they are
adverse to risk then the projects will seem more attractive. Or, if
individuals have little concern with future floods or have limited
knowledge of the probability distribution or losses associated with
these events, then the benefit will be overstated.

Multiobjective Planning

A principal criticism of benefit/cost analysis in water resources
planning generally is that it focuses almost entirely on economic
efficiency criteria without concern for other objectives such as income
redistribution, and social, environmental, and ecological impacts; but
it is possible to use multiple objectives in the planning process.

Multiobjective planning has been federal policy since 1962, when the
following objectives were adopted: development; preservation (e.g., wild
rivers); and well-being of people (e.g., saving of life from floods).
Eleven years later these criteria were broadened by the U.S. Water
Resources Council so that analyses of beneficial and adverse effects of
projects were to be assessed under four general accounts: national
economic development, environmental quality, regional economic
development, and social well-being. The plan selected for authorization
and funding was to meet four tests: technical performance efficiency
(i.e., least-cost means), capability of full realization, and public
acceptability.

The Carter Administration has retained the basic multiobjective features
of the Principles and Standards of 1973 and has added other important
features:

· Emphasis on water conservation measures

· Requirement of the preparation of a nonstructural plan to meet
objectives (e.g., floodplain zoning, etc.)

· Consideration of risk and uncertainty in analyses

· Manuals of procedures for national economic evaluation and evaluation
of environmental quality

· Reconciliation of the WRC Principles, Standards and Procedures with
the requirements for environmental impact statements under the National
Environmental Policy Act in 1969 and the Handbook on Urban and Community
Impact Analysis under coordinated preparation by the Urban Policy Staff,
Office of Community Planning and Development, U.S. Department of Housing
and Urban Development.

For 20 years much effort has been made to develop ways that a policy
maker can systematically evaluate a multicriterion objective
function.^19^ After objectives of the policy proposal have been stated,
attributes must be defined which can measure how well each alternative
meets specific objectives.

A major problem is to define a set of attributes for qualitative
objectives. For example, how does one measure \"preservation and
aesthetics\" in a quantitative manner? One way to measure this objective
is to divide it into subobjectives (e.g., create recreational
opportunities to preserve wildlife) which may then suggest specific
attributes (e.g., number of visitor days in a park).

If several attributes describe a given objective~\ ~then appropriate
weights must be given to them. How well the process is likely to work in
practice is still at issue. It requires very sophisticated technical
analysis and decision making It does not directly address the trade-offs
among alternative floodplain management measures nor explicitly
incorporate the decision process of individuals in the floodplain.

Risk/Benefit Analysis

For several years, both public and government decision makers,
especially persons involved with environmental protection or public
health issues, have become familiar with the concept of risk/benefit
analysis. Increasingly, identification and prevention of
\"unreasonable\" risks to public health and safety are a central
objective of federal regulation. For example, in the House Report
accompanying the Toxic Substances Control Act, this concept is of
central concern:

\"In general, a determination that a risk associated with a chemical
substance or mixture is unreasonable involves balancing the probability
that harm will occur and the magnitude and severity of harm against the
effect of proposed regulatory action on the availability to society of
the benefits of the substance or mixture.. ..

Procedures for determination of such a goal are not straightforward.
Major disagreements exist among the experts on how to deal with
questions of externalities, incommensurables, inequitable distribution
of costs and benefits, discounting future benefits, and valuing
intangible things such as environmental quality.

It is generally agreed that one of the functions of government is to
protect the public against those hazards for which individuals would not
easily be able to protect themselves. This theory supplies the rationale
for government provision of armed services, fire protection, police, and
other services As our society becomes more complex and adopts
technologies which increase our interdependence, the state attempts to
safeguard the citizenry from more and more threats. In so doing,
government has to decide whether the benefits of its action exceed the
costs of that action.

Such decision making never can be absolutely objective. This is partly
because of the difficulty in adequately quantifying costs, risks, and
benefits. These are separated in time, affect different groups of the
population differently) and often appear to be incommensurable. Usually,
costs are measured in dollars, and benefits may include intangible
values such as improved environmental quality. Experiences in the risk
area have demonstrated that policy decisions on incommensurability
require the consideration of social values. These value questions are
intimately connected with the organization and conduct of risk/benefit
analyses.

Risk and benefit are separate and extremely distinct concepts. Much
effort has been made to separate the quantifiable from the
unquantifiable. Risk and safety should mean two different things. Under
the best circumstances, the scientifically and probabilistically
understandable, evaluable data can generate an idea of the nature and
magnitude of risk.

\* House Report 94-1341 to accompany HRl4032, The Toxic Substances
Control Act of 1976.

Social and value decisions based on this and other information represent
the degree of safety which society requires. Despite the best
intentions, value questions and value decisions are intimately
intertwined with the organization and conduct of risk/benefit
analyses.^21^

One extreme approach to concerns about value decisions has been to
assume that for certain risks the public should not be permitted any
choice, or no avoidable risk should be permitted. Such situations are
rare. More commonly, decision makers weigh cost, risk, and benefits and
come to a judgment: a value judgment. If one person making this decision
is a government official, the public is subjected to his or her values
even though both the official and the public may have regarded his/her
judgment as being scientifically based.

To assess risks, benefits, and appropriate governmental policy on
flooding issues is a complex process, and quantitative data must be
juxtaposed with qualitative data. Despite sophisticated application of
statistical arid other scientific principles, identification of the most
advantageous policy remains a matter of judgment which involves social
values.^20^\'^22^

Decision Support Systems

Researchers recently have sought to address policy makers\' needs
through the development of decision support systems. Decision support
denotes the use of computers to help improve the effectiveness of
decision making.

With the use of decision support in floodplain management, makers can
simulate situations for evaluation. For example, a flexible decision
support system enables policy makers to investigate the relative
performance of alternative strategies in various situations\--such as
the 100-year flood or different flood events in an area. Sensitivity
analysis can be performed involving socioeconomic and physical
characteristics of the flood prone area or the nature of flooding. The
computer facilitates data analysis, standardizing data bases so policy
makers can communicate with each other and contrast the relative
performance of different strategies.

The computer does not provide an answer as to which policy or set of
strategies is most desirable for adoption. It enables the policy maker
to fill in the cells of a matrix such as in Figure 8 50 as to articulate
the qualitative and quantitative measures associated with strategies and
stake-holders. The decision support system is a way of organizing data
which may utilize benefit/cost analysis, multiobjective planning, and
optimization models for evaluating the trade-offs among strategies and
for arriving at solutions. Decision support systems users such as
government agencies and the U.S. Congress, are likely to find that
desirable strategies consist of a combination of adjustments for hazard
mitigation. Policy makers still will have to make relevant value
judgments in determining a final course of action.

Future research on flood hazard mitigation must link understanding of
the decision processes of individuals, groups, and communities with
policy formulation and evaluation. Future public issues related to flood
mitigation must include economic, legal, and public health
considerations.

Public Issues

Many issues pertaining to flood mitigation are viewed differently by
various groups. Typically, these publics are coalitions of interest
groups and public officials at various levels of government. Also, a
cadre of professionals become involved in policy making by providing key
information. Among all these groups certain issues emerge while analytic
techniques guiding earlier decisions come under continued scrutiny. The
following examples illustrate the range and complexity of economic,
legal, public health, and statistical issues involved in flood
mitigation policy analysis today.

Economic Issues

Flood losses are often exacerbated by policies which cause inefficient
use of resources and policies which shift the cost burden onto those
relatively less able to bear it. Three economic issues related to such
results illustrate the types of public issues inherent in flood
mitigation efforts.

Impact of Disaster Relief - Federal flood relief has existed for many
years and has risen dramatically during the last two decades. One reason
for this is lack of interest by residents in hazard prone areas in
protecting themselves against the consequences of disaster. Another
reason is lack of local leadership. As more individuals have located in
these regions, both damage from disasters and pressure on Congress to
provide liberal aid after a catastrophe have increased.

Furthermore, although current relief policies have led to an increase in
the net worth of some victims after recovery, these same policies have
allowed a steady worsening of the financial situation of some victims.
Most personal assets such as homes, autos, and savings accounts have
increased during the aftermath, but most liabilities also have
increased. For example, the SBA loan for repairs has, on average,
trebled the long-term debt owed before the flood. This has altered
adversely key financial ratios such as debt/equity and
assets/liabilities. These ratios influence residents\' sense of
financial security. A deteriorated financial position may affect
post-disaster spending patterns significantly and may make residents
more vulnerable to future hazards or family crises.

Who benefits and who loses from disaster relief measures? If low-income
groups are more reluctant to seek or receive low interest loans than
middle- and high-income groups, then policy makers should be aware that
liberal relief may not achieve its desired effect. Specific measures
designed to help particular groups may be appropriate if there is
concern with improving the welfare of these victims relative to others.

Economic Impacts of Natural Disasters - Some evidence suggests that
there are no discernible long-term economic losses; population or
housing impacts to communities struck by natural disasters. The rapid
pattern of recovery seems to be independent of the severity of the
disaster and the amount of external aid received by the area. It may be
tempting to conclude that there is little need to be concerned with
recovery problems of communities following a disaster. At the aggregate
level this may be true, but certain segments of the population may be
adversely affected, such as elderly residents or low-income victims.
Severely damaged public facilities such as schools and public works may
require immediate attention because of their impact on the functioning
of the community.

What is the basis on which relief should be provided to a community
after a disaster? One alternative would be to adopt a damage threshold
which automatically commands or initiates a disaster
declaration.^27\ ^General social aid, such as employment compensation
and health and welfare programs, has been provided in this manner at
times of economic distress, including the aftermath of floods. Private
insurance reimbursements are automatically triggered as well. A more
specific disaster declaration should relate aid to the type of damage,
whether public or private, its magnitude, and its impact. If there are
distributional considerations, then special attention may be given to
certain socioeconomic groups.

Implementation of Alternative Mitigation Measures - After choosing a
particular alternative, the best means of implementing it must be
selected. For example, if relocation is considered desirable, it is then
necessary to decide whether regulation, financial incentives,
persuasion, or voluntary action will best achieve it.

Measures such as building codes and land-use controls represent
government regulations and are backed up by legal enforcement powers.
These are becoming the most widely applied flood management policy
instruments. Their disadvantages may include limitations on the freedom
0 choice and misallocation of resources due to inflexible requirements.
Conversely, regulations are more certain to implement protective
measures in a crisis and may be the only way to bring about the intended
compliance, or demonstration effect, when gains from flood protection
are underestimated.

A second group of instruments, usually termed fiscal incentives,
includes subsidies and taxes. The approach is intended to be
self-enforcing since people will weigh the out-of-pocket costs of paying
a tax (or the opportunity cost of declining a subsidy) against the
marginal benefits of undertaking, or not undertaking, a given course of
action. For example, subsidies are attached to National Flood Insurance
to make policies more attractive. These incentives may not achieve their
desired effects if individuals have imperfect information or misprocess
data; if a tendency to ignore low probability events exists, then
insurance may not be attractive even at highly subsidized rates. Penalty
taxes are much less prevalent as a means of inspiring a desired response
to flooding. Tax instruments for flood mitigation merit further inquiry.

In externality cases, as where the actions of some parties affect the
flood vulnerability of others, an appropriate policy measure could be
based on the delineation and assignment of private property rights. Many
individuals treat rivers, reservoirs) and debris basins, all of which
are normally \"publicly owned,\" as free discharge grounds for debris
and excess water without consideration of damage to others. Assignment
of property rights to individuals or groups, however, would give them
recourse to receive compensation if damage does arise or to sell rights
to their property when a higher value use presents itself. The purchase
of easements as practiced by public agencies in Wisconsin and the Soil
Conservation Service among others follows a similar principle. Although
the property rights solution is somewhat limited in that it is most
applicable to cases in which there are small numbers of participants and
clearly delineable rights, it deserves a trial in flood hazard
mitigation.

A third policy instrument is the more subtle one of moral persuasion,
which amounts to an appeal to altruistic social interest in an effort to
modify people\'s actions. In most cases of mitigation, though, appeals
to ordinary self interest or better informing people about their options
would be more effective.

Key considerations among these policy instruments are the trade-offs
among efficiency, equity, enforceability, and freedom. Ramifications of
each policy instrument as applied to flood hazard need to be examined
more carefully so that wiser choices can be made.

Legal Issues

Increasingly, Americans are taking matters of dispute and conflict to
the courts. Flood mitigation policies and actions may be susceptible to
this trend which may have far reaching consequences for flood managers
at all levels of government.

Dimensions of these issues are not well understood and have not been
studied intensively. Legal issues related to earthquake hazard have
provided insights which may have important parallels for flood
mitigation (Association of Bay Area Governments, ABAG, Earthquake
Preparedness 28,29 Program). Meriting top priority for future research
are analyses of legal issues related to flood mitigation which parallel
those completed for the earthquake hazard.

Land-Use Controls - The 1970s brought a proliferation of state and local
land-use control programs designed to avert or mitigate flood damage.
Through various types of state enabling legislation and favorable
judicial decisions, these programs have become widespread. If this trend
is to continue, laws and ordinances placing restrictions on private
lands must not evoke widespread negative public views. If legal change
is to evolve through human response to flood hazards, proposed laws must
attract popular support.

As use of land-use controls increases, it is likely that several legal
issues will emerge. Some could arise from improper techniques in the
application of criteria. An ordinance restricting land-use could be
challenged on the ground that land included in the hazard zone was
inaccurately mapped. A property owner could have a claim for
compensation if the flood hazard to be avoided results from other
government action. For instance, a Pennsylvania township installed a
small culvert and drainpipe under a road, but the pipe was too small to
accommodate storm flows. The township then mapped as floodplain those
lands which flooded as a result of the township infrastructure design.

More serious challenges could contest the basis for the entire map, such
as a claim that the hazard was improperly calculated, or that blind
adherence to the 100-year flood was unreasonable where special
circumstances require a more flexible criterion.

The most common legal challenge is that a land-use restriction is an
unconstitutional \"taking\" of property, as discussed above. Measures
that avoid property confiscation extremes are among options more
acceptable to the property owner and the public. Several alternatives
exist between harsh and possible impermissible regulation and fully
compensated acquisition by the public. Partial acquisitions may include
these options: purchasing an easement, a covenant, a surrender of
development rights, buying the title and leasing back, temporary or
seasonal flooding rights.

Popular acceptance and judicial approval of land management controls may
be increased by coupling them with environmental protection and
enhancement of recreational opportunities. Further support can be gained
through integration with city-wide and area-wide zoning and land-use
planning. Ideally, use restrictions should not include broad blanket
prohibitions, but should be designed for local needs and, when possible,
leave the landowner some choice of action.

This is a critical matter to landowners. Despite a floodplain
regulation, the owner must be left with a beneficial use, and what it
may consist of can become quite complex. The owner may seek to alter the
land in some way, such as to dredge or fill it, to increase its economic
worth. Courts have differed on this matter and ambiguity exists as to
what may define \"reasonable use\" in varied circumstances. If owners
have the constitutional right to alter the natural condition of certain
floodplains or wetlands, should it extend to all such owners and land?
What should be the rationale for any given right or limitation?

Variance provisions for exceptions may encourage ingenuity among
prospective developers, but these greatly increase the complexity of the
execution of floodplain management. In certain instances, a requirement
of planning permission rather than use prohibition would be desirable,
and permits could be granted for individual developments under adequate
standards. Thus, in the fringe, a large block-like building might be
unacceptable, yet a highrise building on a narrow floodproofed base
might be permissible. In low hazard areas where restrictions can be
minimal, and in rural and fringe areas where land values typically are
lower, tax incentives such as lowered assessments and shelters from tax
raises may be traded for uses relinquished.

Complexities differ in developed areas where land-use controls demand a
rollback of existing development of the floodplain. Generally, removal
of existing buildings or curtailment of an ongoing but nonconforming use
requires a formal taking through voluntary transfer of title or eminent
domain. In fixing the price or determining just compensation, the value
of flood prone property may be discounted by the probability of future
flood damages. Determination of such values often is not done easily nor
without challenge.

In contrast, after flood damage has occurred, prohibitions against
rebuilding or repairing damaged structures may give opportunities for
the public agency to acquire base property at reduced value. Sometimes
this can be coupled with a program in which the agency purchases lots on
high ground outside but nearby the flood hazard area, and sells or
trades these to the victims. Recent experiences suggest that reluctance
to leave flood prone areas may be reduced sharply if victims are
provided with such options. Many residents still may resist because they
may not wish to incur debt obligation. This seems to be true among
elderly victims, especially, for whom a mortgage-free home may have both
symbolic and economic value. In some cases, resistances to such land
takings can be reduced by paying the costs of moving some houses to new
locations. These matters ought to be researched soon.

A variety of legal issues related to land-use controls will become more
complex. Multidisciplinary, legally oriented, research is required so
that new approaches can be implemented selectively and evaluated
carefully for legal ramifications and public reactions.

Liability - Liability means that individuals, or social units
represented by them, are legally responsible for actions, events, or
procedures. Persons who believe that they have suffered some kind of
injury, be it economic, emotional, or physical, may seek redress through
the courts within a context of tort liability. Increasingly, courts are
reflecting a changed judicial attitude toward legal defenses based on
\"Acts of God\" arguments. No longer are all damages resulting from
natural disasters viewed as unavoidable and, hence, liability free.
Technological advances provide important guidelines as to how to build,
where to build, and how to forecast flood events. Those who ignore such
technologies, or fail to implement them in a reasonable manner, may be
held negligent under some circumstances.

Increasingly, the media have nurtured a public expectation for
government officials to reduce the losses from floods. The extent of
this expectation is growing while simultaneously local officials
indicate more uncertainty as to how the courts might evaluate their
actions. One recent survey of nearly 400 local officials indicated that
nearly all viewed tort liability rules as uncertain and unpredictable.
Five general causes of this uncertainty were identified in the study
(Association of Bay Area Governments): lack of clarity in the law,
vagueness of certain tort concepts, unfamiliarity with tort law
concepts, judicial lawmaking, and unpredictable judges.

Substantively, several potential liabilities for local governments
detailed by the ABAG Staff for the earthquake hazard appear to have
relevance for flooding, such as systems and typical public responses. It
is not clear now under what conditions local governments might be held
liable for losses contributed to by their action or inaction. Regarding
earthquake prediction and warning the ABAG Staff concluded:

\"some states provide some immunities if the governor has declared a
state of emergency. In the absence of such a declaration, however, there
are no specific immunities. Therefore, local governments could find
themselves liable. \"

Their recommendation: \"Make decisions about how to respond to an
earthquake prediction or warning at the highest policy level, in order
to maximize the applicability of the discretionary immunity\" (i.e.,
immunity derived from decisions characterized as pertaining to basic
policy, rather than to operational matters, which do not qualify). Other
suggestions were included: establishment of a modern risk management
system, investigation of pooling arrangements for liability insurance,
and re-examination of self-insurance policies.

As a result of serious damage resulting from dam jajiures, it nas been
suggested that strict liability should be the rule for structural
failure of a dam. However, under present law, those damaged by failure
of either dams or levees must bear the burden of proving fault such as
negligent design, construction, or maintenance.

Recent field research has uncovered a different dimension of this issue.
In post-disaster responses, a great deal of emergency assistance is
provided by private citizens guided by altruistic motivations. They are
not representing any agency but just seek to help in the best way
possible. Recently some of those helping have revealed moderate fright
regarding uncertainty as to their legal liability. Uniformly, no reports
have been made of helpers who had misgivings about their behavior in the
disaster aftermath. Later they expressed worry and wondered whether they
could be sued. while this matter awaits systematic empirical
exploration, it appears that much of the public has little understanding
of the workings or meanings of \"good samaritan\" laws. It will be
unfortunate if fear of litigation erodes the scope of voluntary helping
responses in post-disaster settings, which reflect an important core of
American values.

The key question awaiting further study applies both to governments and
to private citizens: What legal liabilities confront those responding to
flood hazards?

Public Health Issues

Germane to flood hazard mitigation are public health issues. Because of
increasing numbers of people at risk in floodplains and in coastal zone
areas, these issues probably will be exacerbated in the future. Four of
the critical issues are discussed here: pre-disaster planning, medical
care, public evacuation, and data collection.

Pre-Disaster Planning - Coordination and communication among units
involved in emergency operations is usually lacking. Although some
communities and states have developed general flood relief programs, a
fragmented approach is the rule. Usually, individual agencies,
hospitals, and governmental agencies have developed individual programs
without recognizing the need to coordinate plans. For example, the
Public Health Service (PHS) has no programs directly related to flood
hazard mitigation nor are any such programs planned.

A fundamental issue involves design of integrated warning systems to
insure successful evacuation of threatened populaces, including the
elderly, minorities, and handicapped.

Medical Care - The proportion of people requiring medical care following
a flood vary between 0.2 percent and 2.0 percent having relatively minor
ailments such as lacerations, abrasions and exposure; burns and
fractures are few. Experience in recent disasters has shown clear
examples of over-reaction. Various mobile hospitals, teams of
specialized surgeons and unprepared volunteers, and useless medical
supplies have been rushed to flooded areas and remained unused while
needed supplies arrived late or not at all. This is partly due to
improper need assessment but mainly due to the flood induced physical
breakdown of communication lines. Until adequate procedures for improved
damage survey and needs assessment are implemented, and a fail safe
communication network is established, such ineffectiveness will
continue.

In contrast, experience indicates that a serious technical design error
has been made in many hospitals and other critical facilities, wherein
emergency power apparatus has been located in areas subject to flooding.
Also, no attention has been given to assuring an emergency water supply
to hospitals without which they cannot function.

Turning to medical practice specifically, experts now indicate that the
age-old practice of mass vaccination to prevent typhoid, para-typhoid,
and tetanus following floods is no longer valid and detracts from the
overall flood relief efforts by taking personnel away from more
constructive pursuits. Although there may be a theoretical risk of
enhanced transmission of enteric infections following floods, accrued
data do not support the theory. More practical prevention strategies are
to aggressively maintain safe water supplies, and if contamination does
occur, then the population should be cautioned to boil water before
drinking it. PHS hospitals have specific plans to provide assistance to
flood victims, and PHS also provides crisis counseling to victims of
flood and other disasters under the authority of P.L. 92-288, the
Disaster Relief Act of 1974. For optimal resource utilization, there is
need to integrate existing plans, identify and develop remedial measures
for existing deficiencies.

Also needed is an integrated approach in floodplain management relating
to public health activities and facilities. For example, water and
sewage treatment plants are usually located in or near low-income areas
which frequently correspond with flood prone areas. The same is true of
animal and insect control facilities. The impact on public health of
flood induced paralysis of these services during the emergency relief
period is critical.

Of major concern to public health is coordinated pre-disaster planning
for emergency relief measures including site selection of critical
facilities.

Public Evacuation - Public evacuation is a lifesaving measure, and new
knowledge of human responses and advanced technological devices now
provide ingredients for workable flood mitigation Systems. If
implemented and maintained, these could produce effective evacuation
responses for a large majority of the public.

Due to limited incomes and other factors, many elderly, ethnic minority,
and handicapped persons reside in flood prone low rent districts.
Additional consideration must be directed toward these populations. Such
individuals function reasonably well within their normal surroundings
but may become somewhat disoriented if urged to leave their residences,
especially if relatives or friends cannot assist them. Research is
required to ascertain the dimensions of this problem and alternative
organizational designs for best dealing with it.

A broad ranging set of mental health needs require attention. Crisis
intervention programs clearly are required, especially following flash
floods which typically produce psychological trauma. The administrative
design of such efforts, and careful evaluation of short- and long-term
impacts, require research.

Another high priority concern is the need to improve dissemination of
current knowledge regarding public health needs related to flood hazard
mitigation both within the medical community and the facility design
community.

Data Collection - A major deterrent to the development of realistic
flood hazard mitigation procedures in public health has been the lack of
a reliable data base. It is now realized that the effects of floods and
other natural disasters on the health of populations can be studied by
epidemiological methods. Death rates can be computed for different types
of floods, and attack rates can be calculated for various types of
disorders occurring in survivors. These indices can be used in planning
appropriate rescue and relief measures. The effectiveness of various
types of assistance also could be assessed if adequate pre-disaster
information were available.

If flood disaster relief is to be improved through policy decisions
based on fact, another issue emerges: development of an epidemiological
approach to the evaluation of flood hazard mitigation related to public
health.

Statistical Issues

Flood frequency prediction is a technical matter pertaining to critical
areas in flood hazard management. Here the interaction among science,
technology, and public policy becomes evident.

Undoubtedly, estimation of future flood conditions is extremely
important to American society and is intimately tied to potential
losses. Forecasts that are too low discourage proper preparation;
overestimated forecasts result in unnecessary expense and anxiety and
compromise the credibility of subsequent forecasts.

While much disagreement exists in the scientific community concerning
prediction methodology there is consensus with the desirability for
using the 100-year flood as the regulatory standard. Consider, for
example, how flood frequencies are determined in the United States.
Shortly after the passage of the Water Resources Planning Act in 1965,
the responsibility for defining a federal flood frequency methodology
was given to the Hydrology Committee of the U.S. Water Resources
Council. The Committee members represent all Federal agencies with an
interest in the subject. Individual members have no power to commit
their respective agencies. The committee is not part of the staff of the
Director of the Water Resources Council, nor is it funded by a line item
in the Federal budget.

The Committee has issued a continuing series of reports. The most recent
is Bulletin 17A (June, 1977) entitled, \"Guidelines for Determining
Flood Flow Frequency.\" Bulletin 17A is intended to be used by all
agency personnel in all situations where gauging station data exist, as
a result of a desire for equity and procedural uniformity in government
decision making. This means that a \"formula\" or standard approach is
to be used, even in special situations where deviations must be
supported by appropriate study and accompanied by a comparison of
results using the recommended procedures.

The mathematics of this method need not be examined here. What is
important is the growing consensus that the Hydrology Committee has
recommended a procedure that may not lead to an accurate or reasonable
estimate of the flood hazard for a given site.^34^

This consensus does not represent a trivial criticism. Scientists never
can know the actual distribution of floods; they can only hypothesize
from available data. Since all observations and all hypotheses have
their limitations, judgments must be made as to which hypothesis or
model is the most satisfactory. There appears to be compelling reason to
conclude that the currently used American choice is not universally the
most satisfactory.

Many scientists and engineers have emphasized that there is no natural
reason that floods should follow particular mathematical laws, and that
there are many indications that they consistently fail to do so. It is
dangerous to suggest or to assume that there is, in fact, a single
theory as to why rivers flood. Different regimes should not and do not
produce similar floods. Hence, it would appear that the generalizability
of the Water Resources Council\'s recommendations on flood flow
frequency should be reevaluated.

The issue raised, which concerns mostly the involved professionals, is
whether or not it is reasonable and desirable to apply the same methods
for defining all annual flood events.

Concluding Remarks

The social and behavioral sciences offer many insights and analytical
tools which can help to interpret public issues pertaining to flood
mitigation. A rudimentary scientific knowledge base now includes
descriptive analyses of human responses to flood events and various
systems to encourage appropriate public behavior such as warning and
evacuation measures. Most of this information awaits dissemination to
local levels of government wherein much of the activity most critical to
flood mitigation occurs, especially nonstructural activity.

Flood mitigation can be improved through research directed at
integrating knowledge of probable human responses and choice of policy
options. These efforts must be augmented with more basic research to
explore and expand the limits of existing methodologies for risk
assessment. Innovative approaches must be developed to deal effectively
with complex economic, legal, public health, and statistical issues.

As research is conducted, there must be a major focus on dissemination
of the information to potential users. Incentives should be built into
nearly all funding programs to insure that the research community *is
*interacting with user groups. Such interaction will facilitate
dissemination of findings and help researchers to be responsive to
topics of users priority and to constraints of implementation
confronting them.

Understanding of human responses to stress, uncertainty, and risk is
imprecise and deficient in methodology compared with engineering and
other technical knowledge pertaining to flood mitigation. This reflects
a historical pattern of minuscule research funding and the complexity of
these social elements. Future policy making can be improved if emphasis
on the social sciences is encouraged.

In the next chapter, a dynamic interplay among these social dimensions
and various engineering approaches to flood mitigation is illustrated in
11 regional case studies documenting how the flood hazard differs
throughout the nation.

References

for

BEHAVIORAL RESPONSES TO FLOODS

and

ASSESSMENT STRATEGIES FOR PUBLIC POLICIES

1 Mileti, Dennis S., Thomas E. Drabek, and J. Eugene Haas. behavior in
extreme environments. Boulder: University Institute of Behavioral
Science.

1975\. Human of Colorado,

2 Mileti, Dennis S., 1975. Natural hazards warning systems in the United

States: a research assessment. Boulder: University of Colorado,
Institute of Behavioral Science.

3 Barton, Allen H. 1969. Communities in disaster: a sociological
analysis of collective stress situations. New York: Doubleday and
Company.

4 Friesma, Paul et al. 1979. Aftermath: communities after natural
disasters. Beverly Hills: Sage Publications.

5 Wright, James D. et al. 1979. After the clean-up: long range effects
of natural disasters. Beverly Hills, California: Sage Publications.

6 Tierney, Kathleen J., and Barbara Baisden. 1979. Crises intervention
programs for disaster victims: a source-book and manual for smaller
communities. Rockville, Maryland: National Institute of Mental Health.

7 Drabek, Thomas E., and William H. Key. 1976. The impact of disaster on
primary group linkages. Mass Emergencies, 1:89-105.

8 Quarantelli, E. 1. (ed.). 1978. Disasters: theory and research.
Beverly Hills, California: Sage Publications.

9 Haas, J. Eugene, Robert W. Kates, and Martyn J. Bowden. 1977. Re:
construction following disaster. Cambridge, Massachusetts: The MIT
Press.

10 Dynes, Russell R. 1970. Organized behavior in disaster. Lexington,
Massachusetts: D. C. Heath and Company.

11 Drabek, Thomas E. et ai. 1979. The flood breakers: citizens band
radio use during the 1978 flood in the Grand Forks region. Boulder:
University of Colorado, Institute of Behavioral Science. 135

12 Burton, Ian, Robert W. Kates, and Gilbert F. White. 1978. The
environment as hazard. New York: Oxford University Press.

13 Burby, Raymond J., and Steven P. French. June 1980. Evaluating flood
plain land use management. Cambridge, MA: paper presented at First World
Regional Science Congress.

14 Kunreuther, Howard, et al. 1978. Disaster insurance protection. New
York: John Wiley.

15 Slovic, Paul, Howard Kunreuther, and Gilbert White. 1974. Decision
processes, rationality, and adjustment to natural hazards. In Gilbert F.
White (ed.), natural hazards: local, national and global. New York:
Oxford University Press, 187-205.

16 Tversky, A., and D. Kahneman. 1974. Judgment under uncertainty:

heuristics and biases. Science, 185:1124-1131.

17 Rogers, E. and F. Shoemaker. 1971. Communication of innovations. New
York: Free Press.

18 Slovic, P., B. Fischloff, S. Lichtenstein, B. Korrigan, and B. Combs.
1977. Preference for insurance against probable small loss: implications
for theory and practice of insurance Journal of Risk and Insurance 44:
237-258.

19 Keeney, Ralph, and Howard Raiffa. 1976. Decisions with multiple
objectives: preferences and value tradeoffs. New York: John Wiley and
Sons.

20 Rowe, William D. 1977. An anatomy of risk. New York: Wiley
Interscience.

21 Jutro, Peter R. 1979. Risk assessment and management: decision makers
proceed with caution. Sludge - Municipal and Industrial Residuals
Management. 2:No. 6.

22 Hardin, G. 1972. Nobody ever dies of overpopulation. Science.

23 Kunreuther, Howard, et al. 1978. An interactive modeling system for
disaster policy analysis. Boulder: University of Colorado, Institute of
Behavioral Science.

24 Vinso, Joseph D. 1977. Financial implications of natural disasters:

source preliminary indications. Mass Emergencies (2).

25 Cochrane, Harold C. 1975. Natural hazards and their distributive
efforts. Boulder: University of Colorado, Institute of Behavioral
Science.

26 National Governor\'s Association. 1978. State comprehensive emergency
management. Washington, DC: U.S. Government Printing Office.

27 Rose, Adam. 1980. Local government emergency management. Boulder:

university of Colorado, Institute of Behavioral Science, NHRWP
(forthcoming).

28 Margerun, Terry. 1979. Will local governments be liable for
earthquake losses? Berkeley, California: Association of Bay Area
Governments.

29 Committee on Socioeconomic Effects of Earthquake Predictions. 1978. A
program of studies on \~he socioeconomic effects of earthquake
predictions. Washington, DC: National Academy of Sciences.

30 Lechat, M. F. 1979. Disasters and public health. Bulletin of the
World Health Organization, 57(l):ll-17.

31 Coolidge, Thomas T. June 1978. Rapid City flood - medical response.
Arch. Surg. 106: 770-772.

32 Curry, Wesley. November 1969. Camille revisited - a critique of
community response to a major disaster. Hospitals, J.A.H.A., 43:
26a-36d.

33 Western, K. A. 1976. Epidemiology of communicable diseases in
disaster situations (Summary). Ann. Soc. Beig. Med trop. 56: 199-200.

34 Wallis, J. R. 1980. Risk and uncertainty in the evaluation of flood
events for the design of hydrologic structures. Occasional paper.
Yorktown Heights, New York: IBM T. J. Watson Research Center.

35 Flood Studies Report. 1975. United Kingdom: Natural Environment
Research Council.

[VIII AREAL FLOOD ANALYSIS]{.underline}

[Introduction]{.underline}

No adequate data base exists, covering the whole country, that would
enable comprehensive analyses of the principal beneficial and adverse
effects of modern institutional means \-- federal, state, local, public,
and private \-- for coping with natural flooding. Thus, a comprehensive,
rigorous *assessment *is not now possible. Only a very few overall
measurements, more or less reliable, now exist.

Areal flood analysis, covering areas of flooding studied intensively,
are the best measurement available to gain current understanding of the
effects of present *institutional *tools *in dealing *with floods. *A
*few of the 20,000 identified potential flood hazard areas are included
within the areal analyses which follow.

Appalachia, particularly prone to flood problems, is represented by two
regional analyses: the Susquehanna and the Tennessee River Basins. Three
areal analyses cover the southeastern and gulf region plus the nation\'s
first and most troublesome area of concern, the Lower Mississippi. Green
Brook, New Jersey, highlights the urban storm drainage problem prevalent
throughout the nation; and Houston, Texas, highlights urban flood
control problems. The analyses of Big Thompson Canyon, Colorado, and
Soldier\'s Grove, Wisconsin, indicate the successes and failures of the
newer institutional responses to major flood events. Both analyses of
the Red River of the North and the Southern California Coastal Plain
present unique and difficult problems.

The locations of areal studies in this chapter are on Figure 9.

[Susquehanna River Basin]{.underline}

[Setting and Key Features]{.underline}

The Susquehanna River Basin drains an area of 27,500 square miles in New
York, Pennsylvania, and Maryland. The Susquehanna River is about 450
miles long and has its source at Lake Otsego, Cooperstown, New York. It
flows in a southerly direction to its mouth at Havre de Grace, Maryland,
where it empties into the Chesapeake Bay.

The average flow of the Susquehanna River is about 39,000 cubic feet per
second (cfs), but this flow is not constant and has varied from a low of
1500 cfs in September 1932 to a high of about 1,130,000 cfs during the
Tropical Storm Agnes flood of record in June 1972.

The Susquehanna River Basin includes three major physiographic
provinces: the Appalachian Plateau, the Valley and Ridge, and the
Piedmont, plus very small portions of the Blue Ridge and Atlantic
Coastal Plain Provinces.

The basin has a continental type climate, somewhat modified by moisture
which periodically enters the area from the Gulf of Mexico and the
Atlantic Ocean.

Although primary control of atmospheric conditions within the basin is
by high and low pressure systems that normally move eastward across the
United States, storms often develop along the southeastern coast of the
United States picking up considerable moisture as they move northward.
Such storms usually bring moderate to heavy precipitation to the
Susquehanna River Basin, and when temperatures are low, these storms
frequently produce large amounts of snow.

Hurricanes and tropical storms also bring varying amounts of
precipitation to the basin and have been responsible for major flooding.
During the passage of Tropical Storm Agnes in June 1972, which produced
the flood of record on many streams in the basin, rainfall amounting to
19 inches was recorded.

Average annual rainfall is about 42 inches over the entire basin. In
extreme years, over 50 inches of rainfall have been recorded at various
places, but drought years have seldom recorded fewer than 25 inches.

Average annual snowfall varies considerably within the basin ranging
from about 28 inches in the southern portions to 85 inches at
Binghamton, New York, with some mountain areas receiving well over 100
inches each winter.

[Types of Floods]{.underline}

The climatic pattern in the Susquehanna Basin is such that floods may
occur at any time of year. Located in the path of major west-east Storm
tracks, the basin receives generous rainfall and heavy snowfall in the
winter season. Historically, most flooding has been caused by general
heavy rains associated with frontal-type storm Systems occurring in
early spring. This type of precipitation falling on heavy snow cover and
frozen ground has produced many of the basin 5 major flood events,
including that of March 1936, the flood of record prior to 1972. In the
winter and spring, major streams often have a heavy ice cover adding to
the flood threat.

During summer months torrential rains associated with severe
thunderstorm activity often cause localized flooding in some of the
smaller sub-basins. In summer and early fall, the basin is also subject
to flooding caused by unusually heavy rainfall accompanying tropical
storms passing through the area.

[Existing Urbanization]{.underline}

Many of the early settlements were established in the river valleys
because of the mountainous terrain and settlers\' need for water
trans-portion and power to develop the basin\'s abundant natural
resources. Although these settlements have expanded through the years,
present urban centers are located essentially on the same sites as the
early small settlements.

Principal urban population centers are the Binghamton-Corning-Elmira
areas in New York State, the Scranton-Wilkes-Barre-Williamsport areas in
the central basin and the Harrisburg-York-Lancaster triangle in the
southern basin.

Total population of the Susquehanna Basin was about 3,600,000 people in
1970, living in 1360 separate municipal entities. The U.S. Department of
Housing and Urban Development (HUD) has determined that *1154 *of these
municipal entities, 85% percent, should be classified as flood prone.

Significantly, too, about 1,000,000 of the basin's population live
within the limits of the 500-year flood, and about 500,000 live behind a
levee/flood wall system of flood protection. The existing vulnerability
and flood damage potential is seen more clearly when one considers that
the delineated floodplain represents only about 4 percent of the total
basin area, and that it was determined after the June 1972 flood that
over 90 percent of the total dollar losses occurred in that floodplain.

[Nature of Problems and Responses Chosen]{.underline}

Even with what has been done to date toward controlling floods in the
Susquehanna Basin, floods will continue to cause human suffering and
create economic hardship. A recurrence of any flood of the magnitude of
those which occurred in June 1889, July 1935, March 1936, May 1946,
November 1950, March 1964, June 1972, and September 1975, would still be
felt acutely in some area of the basin. As land development has
increased, it has become increasingly obvious that minor flooding in
certain areas, which formerly was considered only a temporary
inconvenience, is now causing damages. Few of these areas can be
provided with structural flood protection.

Taking into account existing and planned flood protection projects the
residual average annual flood damages in the Susquehanna Basin exceed
\$40,000,000. Recent flooding experiences associated with Tropical Storm
Agnes have resulted in flood damages estimated at \$3,185,000,000. For
comparison purposes, damages of the previous maximum flood of March 1936
were \$275,000,000.

After the flood of March 1936, response to the need for flood damage
reduction was in structural flood protection provided by the federal
government, mostly by the U.S. Army Corps of Engineers (COE) (Corps),
and by the Commonwealth of Pennsylvania.

As of now, the Corps has constructed a total of 47 projects including 13
flood water retention dam projects and 34 local flood protection
projects. Another federal agency, the Soil Conservation Service, U.S.
Department of Agriculture, has constructed 40 small watershed protection
projects in the basin.

To meet flood protection needs on some of the smaller tributaries, where
projects could not be authorized by federal agencies, the Commonwealth
has constructed 36 flood protection projects including six multipurpose
dam structures. An additional local flood protection project was
completed by New York State in the upper basin.

Total construction cost of all of these flood protection projects
represents an estimated investment exceeding \$460,000,000.

In spite of this, flooding continues to be a serious problem in the
basin. Much of the current potential damage now is concentrated in
unprotected areas near large population centers where growth has put
more pressure on the floodplain. In some cases, structural protection
still may be economically feasible, but in most areas there is obvious
need for nonstructural flood damage reduction.

One of the first steps toward the nonstructural approach was taken after
the March 1936 flood when the Federal-State Flood Forecasting Service
was formed, the forerunner of the present nationwide flood forecasting
service of the National Oceanic and Atmospheric Administration (NOAA).
This was a cooperative program among the (then known as) U.S. Weather
Bureau, the U.S. Geological Survey, and the Commonwealth of Pennsylvania
to develop a better and more reliable river forecasting and flood
warning service. The Weather Bureau provided its technical expertise and
general management, and the Commonwealth provided the staff and funds to
establish, operate and maintain a statewide stream gauging network, a
statewide recording rain gage network, and a flood warning radio network
in the Susquehanna Basin. By issuing accurate and timely flood crest
information during floods the Federal-State Flood Forecasting Service
was able to alert all interests to take appropriate protective action.
Reduction of flood damage and loss of lives resulting from this service
was made evident during field investigations after floods, and savings
far outweighed costs of operation.

The National Flood Insurance Program provided another nonstructural
approach to flood damage reduction. It not only helped to repay the
property owner for part of his loss but also required the municipality
involved to provide assurances to restrict use of flood prone areas
through appropriate legal regulations.

[Changing Responses]{.underline} - After each flood, the usual first
demand from flooded areas is still for structural flood protection. Even
after being provided with information that a flood protection project
cannot be built, some municipalities continue to pursue this approach
doing little to implement a nonstructural program to improve their
situation. The greater number of flood prone communities, however, are
looking at their flood problems in a more realistic way.

Flood problems are receiving much greater attention and the nature of
responses is changing. A significant indication of this is the present
participation in the National Flood Insurance Program. As of September
30, 1979, 69,651 flood insurance policies were in force in the basin
with insurance coverage of \$1,913,000,000. Annual premiums are
estimated to exceed \$5,000,000.

Implementation of statewide floodplain management programs are in
process to help local municipalities to better control the use of their
floodplains. This is being done through a program first to identify the
floodplain then to enact zoning ordinances to control uses of these
areas, assuring that nothing further will be done to interfere with the
ability of the floodplain to perform its natural function.

In another area of nonstructural response, an interagency task force
undertook a careful review of the flood warning system in the basin
resulting in coordinated efforts by basin agencies to improve
reliability and timeliness of flood forecasts. *A *back-up satellite
data assembly system is installed and operational, enabling the
Harrisburg River Forecast Center to obtain river gage readings in spite
of failure of conventional communication means.

In addition, over 40 self-help flood forecast and warning systems,
organized at the local level, are operating to provide complementary
flood warning for areas not routinely covered by the National Weather
Service river forecasting system. Other nonstructural means are
watershed land treatment measures and floodproofing.

[Appraisal]{.underline}

Implementation of structural measures to totally control floods in the
basin is cost prohibitive and there is growing awareness of their
possible adverse impacts upon upstream and downstream communities and on
the environment. Exorbitant cost also would be associated with
relocation of communities or structures from the floodplain.

Each community has its own distinct beneficial and adverse conditions
affecting its choice of solutions to problems of flood damage reduction.
The community\'s location, existing development, economic factors, and
degree of flood vulnerability are important items which require thorough
examination before the best solution is determined.

It appears that in almost all cases the best plan for flood damage
reduction would include a mix of various structural and nonstructural
measures available.

A major flood certainly will occur again. In view of this, strong effort
has been made by responsible agencies to continue the educational
process directing information on flood damage reduction to all levels of
interest.

To plan ahead, the Susquehanna River Basin Commission, in cooperation
with the Susquehanna Economic Development Association - Council of
Governments, a regional multicounty organization, is proposing a pilot
program to test the effectiveness of a comprehensive mix of structural
and non-structural approaches to flood damage reduction. This program
will provide interagency coordination and involvement with 10 selected
communities whose various flood problems are representative of the
region. With direct community involvement, the comprehensive flood
damage mitigation approaches identified can then be used throughout the
Susquehanna River Basin.

[Tennessee Basin]{.underline}

An outstanding example of flood control as an element of multipurpose
water control management exists in the Tennessee basin. There the
Tennessee Valley Authority (TVA) reservoir system was designed to
regulate the main river and major tributaries in the region for
integrated purposes. This development was unique in that a complete
river basin was used as a planning unit, overlapping the boundaries of
seven states.

The foremost operational objectives were navigation and flood control
and, as consistent with these, the production of hydroelectricity.
Through the years additional uses of the water were found. Today the
reservoir system is also operated to provide municipal and industrial
water supplies, regulate flows to minimize the effects of effluents in
including thermal discharges, fluctuate water levels for control of
mosquitoes and troublesome aquatic vegetation, and control flows and
levels for various recreational uses.

From 1933 to 1953, 20 dams and reservoirs were constructed in the
valley, and several existing ones were acquired becoming part of the
system. From 1953 to 1980, three additional dams were completed. This
does not include 16 nonpower projects on tributary streams. Two projects
are in some stage of construction now.

The region overlaps the heart of Appalachia with a drainage area of
40,900 square miles encompassing portions of seven states: Virginia,
North Carolina, Georgia, Tennessee, Alabama, Mississippi, and Kentucky.
The Tennessee River was at once the scourge of the region and an almost
untapped resource of tremendous potential. In terms of flow, the
Tennessee is the fifth largest river in the United States.

[Hydrology of the Region]{.underline}

Mean annual precipitation of the Tennessee Valley is about 52 inches but
has varied between 38 and 65 inches. Snowfall averages about 8 inches
annually but rarely remains on the ground for more than a few days at a
time except in higher mountainous areas. Mean annual runoff is about 22
inches, but it has varied from 11 inches in the driest years to 33
inches in the wettest years. Variation in runoff from month to month is
in sharp contrast to precipitation. In winter and early spring, leaves
are gone from the trees, vegetation is dormant, and lower temperatures
reduce evapotranspiration. As a result, more of the rainfall becomes
streamflow in this period.

[Operation of the Reservoir System]{.underline}

The high priority assigned to flood control by the TVA Act ensured that
the plan of operation for each reservoir would provide storage space for
flood control. Initial investigations revealed that within the Tennessee
Valley, by far the greatest potential for urban damage from floods was
at Chattanooga. Thus, planning of the reservoir system upstream from
Chattanooga was directed primarily toward eliminating, or at least
reducing, potential flood damages in that city.

In designing and developing the plan of operations of the reservoir
system, seasonal occurrence of floods was an important factor. The
definite seasonal pattern shown by long-term records implies that the
full amount of flood storage space need be reserved only during flood
season \--December through March.

Reservoirs in the system fall into two general groups: tributary
multiple-purpose reservoirs and main Tennessee River multiple-purpose
reservoirs; the two are greatly different in method of operation,
relative flood storage capacity, and effect at critical flood control
points.

[Tributary Multiple-Purpose Reservoirs]{.underline} - Storage
reservation for flood control on March 15 is determined as the amount
necessary, in conjunction with other reservoirs and levees, for
controlling the maximum probable flood at Chattanooga. Drawdown of the
reservoir prior to January 1 provides useful water for meeting
navigation and power production requirements during drier months, and
normally it can be accomplished with greater assurance and efficiency
than would be possible during the January 1 through March 15 period. The
lesser reservation on March 31 and thereafter makes allowance for
decreased chance of floods near the end of the valley-wide flood season.
After March 31 the reservoir is allowed to fill more rapidly dependent
upon hydrologic conditions and may be filled to normal maximum level if
rainfall is abundant. Deficient rainfall, combined with heavy demands
for hydroelectric power production during the normal filling period,
April 1 to June 1, will prevent filling of the reservoir, which then may
remain substantially below top level through the summer. A small amount
of flood detention capacity is reserved through the summer months as a
protection against flood producing storms over limited areas.

When heavy runoff occurs during the flood season, discharge from the dam
is reduced or cut off and the reservoir may be temporarily filled above
the operating guide curve thus storing floodwaters and reducing
downstream flood crests. When flood danger has passed, the reservoir is
returned to seasonal level by releasing water at rates that will not
create or supplement downstream flooding. Sometimes this drawdown can be
accomplished by operating the hydroelectric plant at turbine capacity
until the necessary quantity of water has been discharged from the
reservoir. Often, however, it is necessary to release additional water
through sluiceways or spillways to lower the reservoir level more
quickly and regain detention space needed for future rains.

Lowering of the reservoirs to prepare the system for the next flood
season normally begins in early summer and accelerates during relatively
dry fall months. Water is withdrawn gradually, to supplement diminishing
natural streamflow, for navigation improvement and power production. By
late December the reservoirs normally have been returned to low levels,
completing the annual cycle.

[Main Tennessee River Multiple-Purpose Reservoirs]{.underline} - The
annual operation plan for a multiple-purpose main Tennessee River
reservoir also provides flood control storage, conservation storage for
power, and a permanent pool for navigation.

Operating guides for the main Tennessee River reservoirs also require
the lowest reservoir levels during January but unlike the tributary
reservoirs, available flood storage space is so small that low levels
are held until near the end of the flood season before filling to summer
levels. During a flo~o~d control operation, the main river reservoirs
may be temporarily filled to top-of-gates level, if required, thus
storing floodwaters and reducing downstream flood crests.

Lowering of the main Tennessee River reservoirs also begins during the
summer and accelerates during the relatively dry fall months.

[Flood Requirements]{.underline} - The objective of all flood control
operations is the regulation of damaging floods to minimize potential
damage. The existing reservoir system provides almost complete
protection to areas below the tributary dams and a substantial degree of
protection below the main river dams. The principal use of the flood
control storage in the Tennessee River reservoirs below Chattanooga is
to regulate floods below each dam and on the lower Ohio and Mississippi
Rivers.

The 10 large flood storage reservoirs on the tributaries to the
Tennessee have a relatively large capacity with respect to flood volumes
equivalent to 6.4 inches over their drainage areas on March 15 \-- and,
therefore, are operated to store all, or almost all, of the flood
inflow. The eight main Tennessee River reservoirs, which have a flood
storage reservation, have a much smaller flood storage capacity \--
equivalent to about 1.8 inches over their drainage areas, excluding
Kentucky Dam \-- and, therefore, are operated to accelerate preflood
flows downstream, thereby reserving their limited capacity for use in
reducing their flood crest.

[Flood Control Benefits]{.underline}

The success of managing floods is measured in prevented flood damages.
Since completion of the first project, operation of the system has
prevented damages that would amount to over \$2,000,000,000. That amount
is over seven times the portion of reservoir expenses allocated to flood
control. Several major floods inside and outside the valley were
contained in the 1970s. Damages averted during the period 1970-1979
(through June) amount to \$1,693,000,000 at Chattanooga, \$169,000,000
elsewhere in the valley, and \$159,000,000 on the lower Ohio and
Mississippi Rivers.

[Floodplain Management Services]{.underline}

Although its reservoir system has been effective in reducing damaging
effects of many floods, complete flood protection is not provided
downstream of the reservoirs and many areas of the valley remained
unprotected. Since about 1950 TVA\'s approach has been to broaden use of
flood damage reduction measures beyond sole reliance on its flood
control system by encouraging thorough planning for wise use of
floodplain lands. This is the first large-scale example of floodplain
management in the country.

Initially, this program placed emphasis on simply providing information
to assist in making local decisions about wise floodplain use.
Information in 1953 indicated that more than 150 valley communities had
significant flood problems. in many of these communities local leaders
were unaware of the potential for serious flooding. Consequently, early
goals were to create an awareness of the cause and nature of flood
damages and stimulate local action. By 1975 more than 170 flood studies
had been requested through state agencies, and 135 reports providing
information had been published.

The Floodplain Management Services staff of the TVA works with state,
regional, and local officials, developers, builders, private citizens,
and others by applying hydraulic data and engineering and economic
principles to reduce flood losses and flood damage potential through
wise floodplain management practices. Staff engineers and specialists
implement this program by giving assistance to communities in the
development of land-use control regulations designed to prevent unwise
use of floodplain lands, assistance in securing eligibility for sale of
flood insurance, and by providing related engineering or technical
assistance and guidance required for informed planning and for
administration of local floodplain regulations.

The staff provides flood data and analyses applicable to the sites of
proposed developments to local officials, developers, builders, and
private citizens and assistance to federal agencies and others in
meeting requirements of Executive Order 11988 - Floodplain Management.
It also assists communities in making decisions about alternative flood
damage reduction efforts and in obtaining assistance from other agencies
for implementation. It works closely with local officials, state and
federal agencies, and others in integrating flood damage reduction
objectives into local comprehensive development or redevelopment
projects.

More than 100 communities have adopted some form of land-use regulations
to guide development away from the floodplain. In the absence of
specific land-use regulations, many individuals after being informed of
the flood hazards involved have either located facilities outside the
floodplain or minimized their exposure to flood losses by elevation or
protection of the use.

In the Tennessee Valley, as elsewhere in the nation, regulatory power
rests with local governments. Therefore, TVA depends upon local
initiative and strong local involvement in planning for flood damage
reduction. TVA\' 5 experience has shown that there is a lack of
technical expertise at the local level to understand and deal with flood
problems and that technical assistance is needed for floodplain
regulations to be applied effectively.

With technical assistance several valley communities are carrying out
small flood damage prevention projects. Experience has shown that
further reduction in local flood problems in most cases is not best
achieved by federal projects planned solely for flood control. Instead,
flood damage prevention needs to be made an integral part of other
community land-use and facility planning.

[South Florida]{.underline}

Virtually all of South Florida and the entire state\'s Gulf of Mexico
and Atlantic Ocean coastline are vulnerable to hurricanes. In addition
to high winds, the coast is also subject to flooding as a result of
storm surges, hurricane tides which sweep across and inundate islands
and the coastal plain. Flooding also occurs due to rainfall associated
with hurricanes. South Florida is particularly susceptible, as it is
situated in the track of hurricanes approaching from the east, south,
and west. Miami, located in Dade County on the southeastern coast of the
state, is the most hurricane prone metropolitan area in the United
States. Especially since World War II, millions of people, many elderly
and infirm, have moved to this extremely disaster prone area. Because
hurricanes and flooding are so interrelated, this section will examine
hurricanes in detail.

[Hurricane Incidence]{.underline}

The earliest hurricane of record in Florida struck what is now the
Pensacola area on September 19, 1559. Since then big storms have hit the
state with unnerving regularity causing over 2500 fatalities and
billions of dollars\' worth of damage between 1926 and 1975 alone.
During the same period, 32 hurricanes were recorded, the most severe
occurring in 1935 in the Florida Keys. The worst hurricane death toll in
Florida came in 1928 when winds blew water out of Lake Okeechobee,
flooding several communities and drowning over 1800 persons.

[Nature of Hurricanes, Storm Surge, and Rainfall]{.underline}

\"Hurricane season runs from June through November, with a peak in
September, but there have been hurricanes before and after. Hurricane
tracks follow generally curving paths, but they can be extremely
difficult to predict. At maturity, a hurricane may be 10 miles high,
several hundred miles in diameter, and have winds at or well over the
74-miles-per-hour defined threshold of hurricane force. The most extreme
devastation of a hurricane is usually confined to a core area 50 miles
or less in diameter, with squalls extending outward up to 500 miles.

In most parts of the United States, the landfall of a hurricane will
cause the storm to lose energy, the source of which was the warm ocean
where it originated, and begin to die. In Florida, however, a strong
hurricane can strike one coast of the peninsula, weaken slightly on its
passage across the state, and regain hurricane intensity when it reaches
Gulf of Mexico or Atlantic waters again.

Hurricane severity is generally rated on a scale of 1 to 5, with worst
being 5; criteria for measurement include central pressure (in
millibars), wind speed, and storm surge.

[Storm Surge Heights]{.underline}

One of the most dangerous aspects of a hurricane is a general rise in
sea level called storm surge. It begins over the deep ocean; low
pressure and strong winds around the hurricane\'s center (\"eye\") raise
the ocean surface a foot or two higher than the surrounding ocean
surface, forming a dome of water as much as 50 miles across. As the
storm moves into shallow coastal waters, decreasing water depth
transforms the dome into a storm surge that can rise 20 feet or more
above normal sea level and cause massive flooding and destruction along
shorelines in its path. This problem is even more critical when full
consideration is given to the additional impact caused by high,
battering waves which occur on top of the surge.

Florida hurricanes have brought storm surges of 15 feet or more above
mean sea level. The 1935 Keys storm was accompanied by an 18-foot storm
surge. Tampa Bay had 14 feet in an 1848 hurricane, and the 1926
hurricane raised 13.2 feet of storm surge in Biscayne Bay. Hurricane
Donna (1960) brought a storm surge of 13 feet to Islamorado in the
Florida Keys.

Meteorologists at the National Oceanic and Atmospheric Administration
(NOAA) have calculated storm surge heights for the entire
[open]{.underline} coast of Florida, based on what is known of storm
surge from hurricanes striking the state. Calculated storm surge heights
for storms such as 1969\'s Camille and the 1935 Florida Keys hurricane
have reached as high as 32 feet above mean sea level. Those two storms
are considered to ^h^ave produced the most severe hurricane conditions
of record for the United States, and, although such storms may be rare,
they are possible in any hurricane season.

If a coastline is uniformly flat and only a few feet above mean sea
level, the storm surge will spread water rapidly inland. The hurricane
forecasters\' \"rule of thumb\" holds that storm surge diminishes one to
two feet for every mile it moves inland. Thus, a 20-foot surge in South
Florida, wh\~re the land is only four to six feet above mean sea level,
would be felt 7 to 10 miles or more inland although the major hazard is
usually along the shore and offshore islands.

[Wind Speeds]{.underline}

Wind speeds vary greatly between hurricanes and within each storm. Gusts
often exceed sustained winds by 25 to 50 percent. A storm with sustained
winds of 100 miles per hour might have gusts of over 150 miles per hour.
Nonwater wind damage is caused by the wrenching and bending forces
imposed by gusting winds and by rapid increases in wind force as wind
speed increases. When wind speed doubles, four times more force is
exerted on structures.

[Rainfall Variation]{.underline}

Rainfall varies with factors such as hurricane size and forward speed.
During the \"average\" 24-hour period that it takes a hurricane to pass
through a community, there may be 5 to 10 inches of rainfall, flooding
all low-lying areas. Many Florida hurricane rainfalls have ranged from
12 to more than 20 inches. The heaviest rainfall associated with a U.S.
storm fell at Yankeetown, Florida, during Hurricane Easy in 1950:. a
24-hour maximum of 38.7 inches.

[Response]{.underline}

Miami is headquarters of the hurricane research and warning efforts of
the U.S. Commerce Department\'s NOAA. From the National Hurricane
Center, a major office of NOAA\'s National Weather Service, warnings of
approaching storms go out to coastal locations from Maine to Texas and
to the several dozen nations of the Gulf of Mexico and Caribbean Sea.

Advisory operations begin when a storm with hurricane potential is first
detected, usually in satellite imagery. Advisories become more frequent
as the storm intensifies and moves toward coastal areas. Hurricane
warning is added to advisories when conditions warrant: winds of at
least 74 miles per hour, high water, and storm tides. Advisories also
identify probable flood danger in coastal and inland areas, and any
expectation of hurricane-spawned tornadoes. Most warnings give 12 to 16
hours^1^ notice to threatened coastal areas, but a hurricane with an
unusually erratic track can reduce that advance notice. Areas such as
the Florida Keys with limited means of egress require considerable
warning time.

This hurricane warning system has proved to be very effective in
preventing loss. Other measures are helping to reduce hazards:
evacuation and emergency services, relief and rehabilitation systems,
seawall construction, and building codes designed to encourage
floodproofing of structures Also, resident education is given high
priority to help keep hurricane deaths and damages low through
preparedness.

[Pearl River at Jackson, Mississippi]{.underline}

A discussion of the Pearl River flood of April 1979 at Jackson,
Mississippi, is included among the report\'s regional flood analyses
because of its recency, and because it teaches valuable lessons about
flood management.

[Setting]{.underline}

The Pearl River is the principal stream of south central Mississippi.
Its watershed extends 240 miles from its headwaters to the Gulf of
Mexico. The total area drained, about 8700 square miles, includes all or
parts of 23 Mississippi counties and three Louisiana parishes.

The gradient of the Pearl River is relatively flat, averaging about one
foot per mile In most places it is a shallow meandering stream,
nonnavigable except for recreational boating. Land-use adjoining the
Pearl is largely rural. The chief exception is the Jackson Metropolitan
Area with about 320,000 people, located about halfway down the length of
the Pearl in central Mississippi.

Jackson, the state capital, borders the west bank of the Pearl. About
one-fourth of the city\'s land area is flood prone, either from the
Pearl directly or from the 14 tributary creeks which flow eastward
through the city toward the Pearl. Opposite Jackson, the floodplain of
the Pearl is much broader extending to three miles in width; and
political jurisdiction on that side of the river is fragmented among
three incorporated municipalities and unincorporated land in Rankin
County. The east side of the Pearl is much less developed than is
Jackson but has displayed rapid residential and commercial development
during the last two decades.

[Flood Experience]{.underline}

Flooding on the Pearl River is the result of intense rainfall over the
upper basin. Local flash flooding in Jackson also results from surface
runoff to tributary creeks at times of high flow in the Pearl. These
conditions occur frequently, and Jackson has a long history of flood
problems. Prior to April 1979, the flood of record occurred in March
1902 when a discharge of 85,000 cfs at the Woodrow Wilson Bridge caused
the Pearl to crest at 37.5 feet. In December 1961 a much lower discharge
of 66,100 cfs produced nearly the same flood stage of 37.2 feet. This
seeming anomaly was explained in a contemporary newspaper account:

\"At the turn of the century, the railroads, highways, and earth
improvements now in the area were absent and the water had a wider, less
obstructed area over which to travel.\"

In other words, it was clear to those who noticed that the much greater
toll of flood damage in 1961 from a lesser magnitude of discharge was
the result of human encroachment on the floodplain. This in no way
caused Jackson to modify its land-use policies. The 1969 Zoning Map for
Jackson indicates the entire floodplain of the Pearl and its tributaries
within the city limits to be zoned for residence, commerce, or industry.

[Public Response]{.underline}

Before the April 1979 flood, official response to flooding in the
Jackson Metropolitan Area was entirely structural in form. Two major
public works constructed during the 1960s affect flood levels in the
vicinity of Jackson. First is the Ross Barnett Dam which impounds the
Pearl Rivet just north of the city. This project was constructed
entirely with state funds by the Pearl River Valley Watet Supply
District. Although its enabling act refers to \"flood control\" as a
legislative purpose, the Ross Barnett Dam and Reservoir were designed
and operated primarily for recreation and water supply (not presently
utilized). In 1961, the nearly completed dam successfully held back
enough water to lower the crest at Jackson by a few inches; but in April
1979, the reservoir was nearly at peak capacity when the upstream flood
crest arrived. No appreciable storage was therefore available.
Furthermore, the rapid increase of discharge through the spillway to
l30,000 cfs raised subsequent charges that the dam actually worsened the
flood problem downstream.

The other major public works effort to tame the Pearl River was a
program of levee construction and channel modification below Ross
Barnett Dam. This project was planned and constructed by the COE between
1964 and 1968 at a total cost of \$8,000,000, of which \$1,000,000 was
financed locally through bonds. Levees were built to a length of 1.5
miles protecting 420 acres on the Jackson side and 10.3 miles protecting
5870 acres on the Rankin County side. The Pearl was straightened by a
2.3 mile cutoff to flow between the levees. The project was constructed
to accommodate a \"standard project flood\" discharge of 207,000 cfs,
estimated to reach a stage of 42.9 feet. The levees were thus five feet
higher than the 1961 crest. Public statements at the initiation of work
on the levees declared that the project would

\"\...mark the end of the devastating floods which almost annually have
inundated thousands of acres, forced hundreds from their homes, and
threatened to destroy major industries vital to the economy of both
Rankin and Hinds Counties.\"

[The April 1979 Flood]{.underline}

The above prediction was washed away by the \"Easter Flood\" of April
1979. Following a week of flash floods from local storms, the Pearl rose
to an unprecedented crest of 43.25 feet. This exceeded the stage of the
standard project flood despite a discharge far less than 207,000 cfs.
About 17,000 persons were displaced from their homes in Jackson. Flood
damage was inflicted upon 1900 residential structures, 730 business and
industrial firms in 298 structures, and upon a large number of public
facilities including a new \$70,000,000 sewage treatment plant, the
Mississippi Coliseum, State Natural History Museum, and numerous
electrical substations Mayor Dale Danks, Jr., of Jackson estimated total
damage to his city at \$500,000,000. Total federal allocations for
assistance to public and private victims of the Pearl River flood of
1979 were estimated to be \$375,000,000. This included grants under the
President\'s Disaster Fund, Small Business Administration disaster
loans, and subsidized flood insurance payments by the Federal Insurance
Administration.

Jackson bore the brunt of losses in the Pearl River flood. In part, this
resulted from the failure of the west bank levee to restrain floodwaters
from reaching the \"fairgrounds\" where much new investment had been
located since the 1961 flood. Additional widespread damage was inflicted
on residential and shopping facilities in northeast Jackson where no
levee protection exists. Meanwhile, on the east side of the Pearl,
emergency flood fighting by the COE, National Guard, and volunteers
succeeded in protecting the levee against overtopping. Ironically, much
of the land protected by the east side levee is undeveloped.

[Implications for Public Policy]{.underline}

The Pearl River flood of April 1979 bears many lessons for\' public
policy both locally and nationally. The following discussion will
consider six key issues.

[1. Overconfidence in Structural Flood Control]{.underline} - The
boundless optimism of public officials during the 1960s concerning the
\"elimination of the flood threat\" for Jackson through levee
construction was obviously misplaced. First, the flood control project
did not purport to protect areas along the river in northeastern
Jackson. Admittedly, much of this land was developed under county
jurisdiction before being annexed to the city in the early 1970s; but no
public authority \-- federal, state, regional, or local \-- apparently
called for limitation of building in exposed portions of the Pearl
floodplain.