National Science Foundation

A Report on

FLOOD HAZARD MITIGATION

Washington, DC

September 1980

NATIONAL SCIENCE FOUNDATION

WASHINGTON D C 20550

OFFICE OF THE DIRECTOR

September 11, 1980

Honorable George E. Brown, Jr.

Chairman, Subcommittee on Science, Research and Technology

Committee on Science and Technology

House of Representatives

Washington, D.C. 20515

Dear Mr. Brown:

It is my pleasure to transmit to you the Flood Hazard Mitigation Study
conducted by the National Science Foundation (NSF). The NSF
Authorization Act for Fiscal Year 1980 (PL 96-44) instructed the
National Science Foundation to conduct a study of flood hazard
mitigation policies and transmit the report to Congress by September 30,
1980. As requested, the Problem Analysis Group of the Directorate for
Engineering and Applied Science was assigned the responsibility for the
report.

The report was written by a committee of experts in flood hazard
mitigation from outside the Foundation. The committee, called the
External Working Group by NSF, was chaired by Dr. William C. Ackermann.
Group members prepared the analytic body of the report and arrived at a
series of conclusions and recommendations that represent their best
judgment of the strengths and deficiencies of flood hazard mitigation
policy, technology, and research. They were aided in their deliberations
by an Interagency Coordinating Committee, organized by NSF at the
request of Congress to assure sufficient input from the several agencies
responsible for the many aspects of flood hazard mitigation. This
Committee was especially cooperative, offering many helpful suggestions
for structuring the study and critically reviewing draft reports.

The report has not been reviewed in the context of the Administration's
budgetary and policy positions. It presents the views of the External
Working Group and should not be construed as representing the position
of the Administration or the Federal agencies represented on the
Interagency Coordinating Committee.

We are pleased to deliver this report to you and hope it will be useful
in your deliberations concerning flood hazard mitigation policies and
research.

Sincerely yours,

Donald N. Langenberg

Acting Director

ACKNOWLEDGMENTS

The National Science Foundation was requested to undertake a study of
flood hazard mitigation policies and research by the House Committee on
Science and Technology. Under the guidance of our Problem Analysis
Group, a committee of outside experts, chaired by Dr. William C.
Ackermann, was organized to conduct the study. The Foundation extends
its appreciation to Dr. Ackermann for his leadership and skill in
chairing the group of experts who so actively participated in the
dynamic process used to produce this report. We appreciate the tireless
devotion of this group to producing a report that would integrate their
various technical, behavioral and institutional perspectives on flood
hazard mitigation.

Special appreciation goes to the members of the Interagency Coordinating
Committee, who contributed substantially to the study through their
review of the planning phases and final review and criticism of the
draft report.

Jack T. Sanderson

Assistant Director for

Engineering and Applied Science

[CONTENTS]{.underline}

[Chapter]{.underline}

Preface

Contents

Executive Summary

I Introduction

II Nature and Causes of Flooding

III Flood Damages: Trends and Geographical Distribution

IV Approaches to Flood Mitigation

V Institutions and their Functions

VI Behavioral Responses to Floods

VII Assessment Strategies for Public Policies

VIII Areal Flood Analyses

Susquehanna River Basin

Tennessee Basin

South Florida

Pearl River at Jackson, Mississippi

Lower Mississippi River Valley

Green Brook Watershed, New Jersey

Houston, Texas

Big Thompson Canyon, Colorado

Soldiers Grove, Wisconsin

Red River of the North

San Diego Area

IX Policy Impact Analysis

X Conclusions and Recommendations

Appendix A - Federal Agencies Concerned

with Flood Hazard Mitigation

Appendix B - Selected References in Flood

Hazard Mitigation

Appendix C - Membership of Responsible Committees

NSF Study Group

External Working Group

Interagency Coordinating Committee

Appendix D - Glossary

PREFACE

Floods result in extensive loss of lives and damages measured in
billions of dollars annually, despite large expenditures for civil works
and other flood hazard mitigation measures.

Concerned for the safety of their constituencies and for the
effectiveness of federal monies spent for various flood hazard
mitigation strategies, Congress instructed the National Science
Foundation (NSF) to conduct a study of flood hazard mitigation and
report to Congress with specific program recommendations by the end of
the fiscal year 1980 (PL 96-\~\~). In the Report of the Committee on
Science and Technology (No. 96-61) on House Authorization Bill (HR
2729), the Committee requested that the NSF:

\"\...undertake an evaluation of the problems and needs of flood
prediction, the effect of changing climatic condition(s) and topography
on flood potential, deficiencies in flood recovery policy, the practical
application of science and technology in engineering and architectural
design for structures in flood plains, and such other flood related
matters as the Foundation deems appropriate.\"

NSF was further instructed to undertake this study with the assistance
of a broadly constituted group of outside experts and to involve full
participation of other agencies that are concerned with flood hazards,
including the Federal Emergency Management Agency, the Corps of
Engineers, the National Oceanic and Atmospheric Administration, and the
Water Resources Council. The study was to include recommendations for
Federal policies, action by Federal agencies, and action by other
sectors of society.

On October 25, 1979, the Assistant Director, Directorate for Engineering
and Applied Science, formed the NSF Flood Hazard Mitigation Study Task
Group, which held its initial meeting on October 26 to discuss the
composition of an External Working Group and an Interagency Coordinating
Committee. Effort was immediately initiated to contact potential members
of the external group. On November 21, the Director of the National
Science Foundation wrote to heads of 20 departments and/or agencies
asking for the designation of representatives to serve on the
Interagency Coordinating Committee which held its first meeting on
December 12. Formation of the External Working Group was completed in
December and its initial meeting was held on January 11 and 12, 1980.

Subsequent meetings of the full External Working Group were held on
February 8 and 91 April 11 and 12, May 16 and 17, and June 6 and 7. On
July 13, 1980, Federal agency representatives on the Interagency
Coordinating Committee and the National Science Foundation Flood Hazard
Mitigation Task Group were asked to review a draft of the report. This
draft did not include the bibliography, literature citations, glossary,
*photographs, graphics or the Executive Summary. A subcommittee of\' the
*External Working Group met on July 11 and 12 to consider the agencies\'
comments and revise the draft as appropriate Recommendations of the
subcommittee were presented and discussed at the final meeting of the
full External Working Group on July 25 and 26. Those recommendations
that were accepted were incorporated into the final draft of the report.
The Interagency Coordinating Committee Members did not have the
opportunity to review the report after this point.

Though the report is the result of the combined effort of many, it is
the product of the External Working Group and reflects their serious
concern for the issues in flood hazard mitigation and their best
judgment about policies, research, and technology. The report has not
been reviewed in the context of the Administration\'s budgetary and
policy positions. Thus, the final report should not be construed as
representing the position of the Administration or the Federal agencies
represented on the Interagency Coordinating Committee.

Presentation of this report is accompanied by the expressed hope by all
who participated in its preparation that it will provide a better
understanding of floods and contribute toward the mitigation of flood
damages.

Lynn Preston NSF\
Study Group Chairperson

Edward Bryan\
NSF Study Group Leader

[EXECUTIVE SUMMARY]{.underline}

Innovative approaches and increased attention to flood problems
nationwide are required if the United States is to arrest, much less
reverse, rising flood losses and the social and economic burdens they
place on people and the nation\'s tax-supported flood-relief
institutions. Without such an effort, flood losses will increase
steadily, particularly in urban areas.

Congress instructed the National Science Foundation to conduct a Flood
Hazard Mitigation Study during fiscal year 1980 and to report, by the
end of the year, specific recommendations for federal policies and
actions that should be taken by federal, state, and local agencies and
by other segments of society. Specific instructions regarding content of
the study are to be found in House Report 96-61 which accompanied H.R.
2729, the National Science Foundation Authorization Act for 1980. This
report also emphasized the fact that despite past expenditures of
billions of dollars for flood control measures, floods causing losses of
life and damages also measured in billions continue to occur annually.

[The hard facts are these]{.underline}:

Floods may indeed be natural phenomena, but their impact is often
aggravated\-\--if not actually caused\-\--by man\'s unwise activities
and occupation of floodplains. Such problems have been exacerbated by
urbanization.

The age-old hope for relief from flood problems by flood
[control]{.underline}, per se, has given way to a realization that a
more realistic goal is flood hazard mitigation.

Although 90 percent of all Presidential declarations of an emergency or
major disaster involve flooding or flooding in combination with other
weather problems there is no comprehensive national policy on flood
problems.

Average annual national flood damages have been increasing during this
century at 4 percent annually in real dollars. There is some indication
that this rate has accelerated during the last decade to 6-7 percent. A
1980 survey by the Water Resources Council has estimated that expected
damages in 2000, just twenty years from now, will exceed \$4,300,000,000
(in 1975 dollars). Losses from urban and urbanizing areas will increase
the most.

Tragically, the \$4.3 billion dollar figure will be reached in spite of
improved management of the floodplains. Without such improvements, the
damages could approach \$6,000,000,000.

Although annual loss of life is likely to continue to average in the low
hundreds, it must be remembered that 238 lives were lost in just two
hours at Rapid City, S.D., in June, 1972, and 6000 were lost in tidal
surges caused by the 1900 Galveston hurricane. There is great concern
that thousands more will be lost if a great storm brings tidal surges to
the heavily populated coastal and barrier islands areas; it is projected
that a high tide hurricane surge in New York City Harbor could isolate
and have serious impact on 1,300,000 persons in that city alone.

Flooding may produce some benefits, such as nutrient deposition on
agricultural lands or groundwater recharge, but the preponderence of
potential damage makes flooding the nation\'s continuously worst natural
hazard. A particular earthquake or tornado or volcanic eruption, for
example, may inflict extensive damage, death, and injury on a local
area; but year in and year out floods continue their seemingly
inexorable assault on man and his way of life. Nevertheless, the fact
that they occur with or without warning at varying intervals and
locations has significant effect on the public\'s continuing perception
of the flood hazard and on the use people choose to make of flood prone
areas.

Past approaches to mitigation of the flood hazard have ranged from
warnings and preventive measures, such as construction of dams and
levees, before a flood to costly relief and rehabilitation after the
event. Levees and reservoirs of all sizes have been widely used for over
a century, and even more extensively since the 1930s. Over the past
decade warnings, evacuation, preventive land management practices,
floodproofing, and insurance have been utilized to a limited extent,
especially since passage of flood insurance legislation with its related
land-use requirements in the 1960s and 1970s. Relief measures are
extensive and expensive and have become more complex as the size of the
problem and dependence on government to deal with almost every aspect of
the flood program continues to grow, and the responsibility for coping
with the flood threat has become proportionally less incumbent on
individuals and local groups. At the same time, requirements for
administrative or operational actions and funding have become
increasingly the province of higher levels of government \-- state,
regional, and federal.

There are two major and unique findings of this study: primary
responsibility for flood hazard mitigation efforts should be at the
local government level, and social aspects of floods deserve a great
deal more attention.

Complete planning of flood hazard mitigation measures requires
consideration of different aspects, including flood control, floodplain
management, and stormwater management. Responsibilities for planning the
various aspects is held by several federal agencies and by state and
local governments. It is recommended that the Water Resources Council,
in coordination with the agencies concerned, develop a methodology and
procedure for the accomplishment of complete flood hazard mitigation
plans.

The study supports the views expressed by former Mayor Don Barnett of
Rapid City, South Dakota, in an interview after his community was well
into its costly recovery from the June 1972 flood.

\"Elected public officials,\" he said, \"must give the same attention
and priority to their drainage problems as they give to their police and
fire problems. In the history of Rapid City, perhaps 35 people have died
in fires and another 35 have been killed during the commission of
crimes, but in just two hours, 238 died in a flood.\"

Altogether, since the passage of the Disaster Relief Act of 1974 (PL
93-288), funds obligated from the President\'s Disaster Relief Fund for
assistance to flood victims for calendar years 1974 through 1979 exceeds
\$1,700,000,000 \-- including \$172,000,000 for individual family
grants, with the states contributing another \$57,000,000 as their share
of these grants.

The foregoing figures are just a partial listing of flood related
expenditures by government agencies. They do not include the extensive
flood protection and relief programs of the Corps of Engineers, the Soil
Conservation Service, and numerous other federal, state, and local
agencies or those of private individuals and groups which are not
reimbursed government.

The slow but steady growth of the National Flood Insurance Program has
made flood insurance the single largest nonrepayable source of
assistance to flood victims, exceeded only by low interest Small
Business Administration disaster loans. However, flood insurance heavily
subsidized so far by the federal government represents a considerable
government expenditure over and beyond premium income. In the past year,
the Federal Insurance Administration (FIA) began concentrating its
efforts increasingly on the larger and more flood prone communities,
emphasizing technical assistance with the development of adequate
land-use and floodplain management, regulations; and, in post-flood
situations, FIA is beginning innovative use of land acquisition to
relocate families out of the paths of future floods.

In 1977, the President of the United States issued Executive Order 11988
calling for federal agencies to take appropriate steps related to
reducing the nation's flood vulnerability, and on July 10, 1980, the
Office of Management and Budget gave the new Federal Emergency
Management Agency lead responsibility for coordinating the efforts of
all federal agencies in bringing flood hazard mitigation requirements to
bear on planning to avoid future flood disasters and post-flood disaster
relief and reconstruction efforts.

Nevertheless, the study found many areas in which good beginnings need
to be nurtured with infusions of funds, staff, and program innovation.
Traditional efforts need to be strengthened \-- as in forecast, warning,
and response capabilities. The accomplishment of some of the study\'s
recommendations will require a reordering of priorities on staff and
funds; accomplishment of others will require broader awareness and
support by the public, officials, and other leaders at the local, state,
and federal levels.

Considering the preceding findings, the report makes the following major
conclusions and recommendations:

· Floods are not subject to complete control but their damaging effects
can be mitigated.

· Floods are the most consistently destructive natural hazards in the
United States, and the upward trend in damages continues in spite of the
nation's investment in structural and nonstructural measures.

· Urbanization increases flood peaks on small streams from two to six
times.

· High priority should be given to flood frequency data research, and
frequency prediction methodology should be improved.

· The upward flood cost trend can be moderated through comprehensive
floodplain, stormwater, and coastal zone management measures that are
economically, environmentally, and socially cost effective.

· Flood hazard mitigation strategies should reflect mixes of structural
and nonstructural approaches appropriate to the circumstances.

· Comprehensive flood hazard mitigation plans for coastal areas,
especially barrier islands, should be developed to counter the
continuing and inadequately planned growth in such regions.

· Potential benefits from structural flood control measures are often
lost through subsequent, unwise development in supposedly protected
areas; hence, it should be legally required that no federally funded
structural or nonstructural flood damage reduction measures shall be
carried out unless there are accompanying appropriate floodplain
regulations.

· Because continuing building in floodways increases property and lives
at risk, federal, state, and local standards should be changed to
prohibit any development that will increase flood elevations on adjacent
or nearby property unless the builder takes legal steps to protect the
other property owners who will be affected.

· Use of the 100-year flood standard for flood hazard regulation should
be continued; the 500-year standard should prevail in relation to
critical facilities.

· Action should be taken to eliminate flood insurance subsidies after
repetitive flooding in high hazard areas.

· Nationally consistent standards for floodplain mapping and regulations
for use should be developed to include the impact of urbanization and
detention storage on future flooding.

· A greatly expanded and coordinated data collection and reporting
effort is needed to correct serious deficiencies in the information
available for use by those responsible for developing and maintaining
flood hazard mitigation strategies and policies.

· There should be accelerated conversion of all flood prone communities
into the regular phase of the National Flood Insurance Program.

· All levels of government should accelerate the acquisition of the most
flood prone areas for open space uses.

· There must be increased nationwide dissemination of educational and
design information. The same is true of research findings from the
social and behavioral sciences.

· A determined effort is required to integrate and strengthen the
existing forecasting aspects of the flood warning system.

· Warning and response systems should be expanded and better integrated
so that local response systems can be effectively linked to regional and
national warning systems.

· The July 10, 1980, initiative assigning lead agency responsibility to
FEMA for coordinating the implementation of hazard mitigation steps with
post-disaster relief and reconstruction efforts should be supported, and
FEMA should be provided adequate funds and technical capability for
carrying out the responsibilities assigned in this initiative.

· The Water Resources Council, augmented by FEMA membership, should
carry lead responsibility for establishing and maintaining technical
standards and for relating flood mitigation to other aspects of water
resources management.

· FEMA should, under existing authorities, develop performance standards
for local flood hazard mitigation planning and implementation and take
appropriate action against communities failing to meet such standards.
The Congress should direct all federal agencies to deny flood relief and
recovery assistance to all local governments so designated by FEMA.

· There should be strong enforcement of Executive Order 11988 by federal
agencies to end federal support of construction in riverine and coastal
flood hazard areas. States should be encouraged to adopt state policies
and laws comparable to the Federal Executive Order.

· The Water Resources Council should, in coordination with appropriate
federal agencies and the states, develop a plan for comprehensive
analysis of the impact of flood hazard mitigation policies.

· The Congress should authorize a three-year Flood Hazard Mitigation
Study Commission for the lower Mississippi Basin to recommend alternate
solutions to the area\'s flood hazard mitigation needs.

· Research should be undertaken to accurately assess the socioeconomic
benefits and costs of flood hazard mitigation methods.

· Because policy makers are bound by the realities of public opinion and
the constraints of laws and regulations that are subject to change or
reinterpretation, continuing study is needed of public attitudes towards
flood hazard mitigation measures.

· FEMA and researchers should evaluate the ways in which flood hazard
mitigation is presented to residents of hazard prone areas and seek to
develop information dissemination methods with greater impact than those
presently in use.

· Interdisciplinary research should be conducted on the constraints and
incentives on local governments related to adoption of flood warning
systems and improved floodplain management and on the workings of
multiorganizational warning, emergency, relief, and recovery activities.

· There needs to be more knowledge of the short- and long-range mental
and physical health impacts of floods, with special emphasis on the
young, the elderly, the handicapped, and other special population
groups.

· The present and potential roles of financial institutions and the
private insurance industry in relation to flood hazards and risk
management need to be better understood to determine how these and the
real estate industry can be encouraged or required to stimulate private
property owner's awareness of flood hazards.

· The Congress should recognize the major role appropriate to local
levels of government in planning and implementing flood hazard
mitigation measures, except in intra- or inter-state situations, and
should assure that the availability of federal flood insurance and other
forms of assistance should be contingent upon effective local land-use
planning and implementation. Research should be done on ways in which
the federal and state governments can carry out their programs while
still strengthening the assumption of responsibility at the local
governmental level.

· Background information, including specific studies of local and
regional flood disasters and river basin problems, leading to the
foregoing and other conclusions and recommendations will be found in the
body of this report. This report was prepared by an \"External Working
Group\" composed of men and women with many years of experience and
expertise in flood problems and disaster response, natural hazards law
and research, who despite their diversity of backgrounds share a concern
for the ultimate victims of misguided flood hazard policies and
practices \-- the family whose way of life is invaded by the impact of
rising waters or coastal storm surges and the taxpayer who bears the
increasing burden of flood and flood related costs.

[I INTRODUCTION]{.underline}

[Geomorphology and Floods]{.underline}

If a visitor from far-distant space were ever to approach the planet
Earth, he would be struck by its heavy cloud cover and the vast areas of
oceans, signs of the abundant water which makes life as we know it
possible. For untold millions of years, moisture has evaporated from the
seas, the ice caps, the land and its vegetation, and the moisture has
precipitated back to the surface in the form of snow and rain in the
endless hydrologic cycle. On different parts of the earth, the shifting
atmospheric conditions reacting on land forms have created widely
varying precipitation zones, from deserts to rainforests. Runoff
gradually erodes the land and rocks, and forms the streams and rivers
through which the waters reach the sea. These streams have channels
through which the water flows more or less continually. Larger flows
occasionally occur, passing over the normal margins of the streams and
over the land beyond. Large flows are known as floods; and the broader
areas inundated are the floodplains.

Similarly, the ocean shorelines are dynamic and shifting, and during
geologic time have been impacted by the forces of tides and storms.

Floods are a basic phenomenon of nature and are only partially
predictable in timing and in magnitude. They may be caused or
accentuated by man\'s activities; and, conversely, the damage from most
floods can be minimized by various manmade programs. The occurrence of
conditions causing floods is largely beyond human control and the
elimination of all flood damage is presently unattainable.

[Significance of Floods as a Natural Disaster]{.underline}

From a national economic viewpoint, floods, both riverine and coastal
are the most destructive category of natural hazards in the United
States. Other natural hazards to which floods can be compared are
hurricane wind damage, tornadoes, hail, earthquakes, and landslides.

Regarding loss of life, flood hazards are roughly comparable to those of
tornadoes, each averaging more than one hundred lives a year during the
period 1925-1972. Less readily quantified, but important, are the public
health effects of floods when they inundate water supply and sewage
disposal plants leaving deposits of mud and pools of polluted water.

The economic losses to homes and personal property, crops, business
facilities and stock, utilities, and transportation are striking
manifestations of flood losses. Perhaps as large a magnitude of loss is
incurred by establishments which never get wet but are forced to shut
down because their suppliers or supply routes are damaged. It is
philosophically impossible to set a monetary value on human life; but if
lives are assessed by the one time federal standard of anticipated
future earning power of individuals, at average rates of income, then
the losses of property during the floods, and related indirect and
intangible associated damages, far outweigh the monetary value of the
lives lost.

Although floods on large rivers attract most national attention, the
little-noticed floods on small and upstream streams are also important.
The flood damages in upstream areas were estimated at \$1,700,000,000 in
1975 out of an estimated total flood cost of \$3,800,000,000 that year.
Over the next few decades increases are anticipated in urban and
miscellaneous property damages, with crop damages remaining about the
same.

[Rising National Concern]{.underline}

Mounting flood losses in recent years have led to a growing concern with
the effectiveness of existing approaches to flood hazard mitigation. The
present report, in response to a Congressional directive, is a
reflection of this concern. Although distinctive in many ways, this
report is not the only recent or on-going contribution to the subject.
Among many efforts is the recent report, \"Issues and Options in Flood
Hazards Management,\" by the Office of Technology Assessment of the
Congress of the United States.

The Water Resources Council published the report, \"A Unified National
Program for Flood Plain Management,\" in September 1979, and within the
past year has issued other reports dealing with various aspects of the
flooding problem.

The National Oceanic and Atmospheric Administration currently is
conducting a systematic review of all federal programs significantly
affecting coastal resources including the flooding problem.

Outstanding among university and other research institution projects is
the Program on Technology, Environment and Man at the University of
Colorado which has assessed research needs and made numerous
contributions in the flood hazard field.

At state and local levels interest is accelerating in implementing flood
management measures and informing citizens through institutes and other
means.

In contrast to these and other efforts, however, the present report
focuses on flood hazard mitigation and has many unique emphases. Written
by a group of experts, none of whom is affiliated officially with any
agency directly responsible for administering federal policy, the
physical aspects of flooding are juxtaposed against the human dimension.

Thus, much attention is devoted to various behavioral and social aspects
of the problem, especially group and individual decision making
processes regarding low probability events. Clearly, the flood hazard
must be viewed within existing institutional contexts and competing
value priorities. This report introduces many legal, economic, and
public health issues which will confront decision makers at all levels
of government during the coming decade.

The report also concludes that new data bases are required so that
developing techniques of policy impact analysis and decision support
systems can be used to assist policy makers identify the most
appropriate mix of flood hazard adjustments. As pressures of urban
development intensify, flood mitigation \-- in the broadest sense of the
term \-- must become an integral facet of comprehensive community
planning, including such diverse matters as stormwater management and
floodplain land-use.

The report devotes little attention to the agricultural component of
flood hazard mitigation, although such losses presently constitute about
one-half of the national total. Instead, attention is directed almost
entirely to urban and urbanizing areas where losses are mounting
rapidly.

[Nature and Organization of Report]{.underline}

This report deals with basic causes, approaches, responses, and issues
which it is hoped will lead to policy changes related to flood hazard
mitigation. It discusses successively the nature and causes of flooding
and its geographical distribution, damages, and trends. It reviews
available means for coping with floods and details existing governmental
and private institutions involved with mitigation.

Two chapters concern basic human responses to stress, uncertainty, and
risk. This is followed by a collection of a real flood analyses and
another on policy impact analysis. These highlight the necessity to
measure the impact and effectiveness of the multiple programs being
applied in real or simulated circumstances.

Findings and conclusions emerge at numerous points in the report, and
these are summarized in a final chapter on conclusions and
recommendations.

Appendices note the principal federal agencies concerned with flood
hazard mitigation, selected references, membership of responsible
committees, and a glossary of terms. Among these committees listed, the
NSF Study Group organized the study which led to this report, monitored
its progress, and reviewed the final draft. The External Working Group
wrote the report, and the Inter-agency Coordinating Committee offered
numerous suggestions during the organizational period and reviewed the
draft report.

[II NATURE AND CAUSES OF FLOODING]{.underline}

[Flooding Along Streams]{.underline}

Flooding in riverine areas occurred under natural conditions long before
the existence of man. Natural flooding events become a problem requiring
intervention by various means because of man\'s activities in the
floodplains.

[Variability of Floods]{.underline}

Floods are characterized by great variability, both in time and space.
Within a given climatic regimen, tremendous variations in precipitation
occur due to different effects of cyclonic storms, thunderstorms,
hurricanes, snow melt, and other weather phenomena. Only by chance is
there any regularity in the size or character of floods. When a storm
occurs which is of a magnitude equalled or exceeded, on the average,
once in ten years, there is no tendency whatsoever for a ten year
interval to pass before the next such occurrence. Except for events
related to an annually occurring condition, such as snow melt, a second
\"ten year\" flood or a larger one, is as likely to occur two weeks
after the preceding major flood as at any other time.

There is also a tremendous locational variation in flood occurrence, and
the different regions of the United States have very different flood
regimes. Floods in the Pacific Northwest usually occur due to winter
rains and snow melt, but in Florida hurricane floods of summer or fall
are of main concern. The semiarid portions of the country, such as the
western Great Plains and Rocky Mountain states, can be subject to
localized but excessively violent storms and floods, particularly in
summer. In most of the United States the largest floods are likely to
occur in the springtime due to heavy rains.

The spatial impact of floods on a stream may be broader than expected.
Where a floodplain has been mapped, or is identified in a community by
past experience, inhabitants outside the floodplain may feel completely
safe; but this confidence may be misplaced. Unexpectedly, a large flood
from some sudden magnitude of rainfall may inundate areas previously
considered safe. For example, in 1935, on the Republican River in
Kansas, a flood occurred which was six times the discharge of the
previous flood of record.

[Kinds of Floods]{.underline}

The lower Mississippi River produces the largest natural flood flows in
North America. These include a long slow rise of the river, predictable
weeks in advance, with waters originating in rains and snow melt
hundreds or even thousands of miles away. If the extensive levee systems
were not there, the floodplain would be one hundred miles wide, as it
was during the greatest flood of record in 1843. At the other end of the
spectrum are the highly localized cloud burst floods which may come
roaring out of a canyon in a breaking wave of water many feet high,
churning together mud, rocks and debris, moving boulders and trees, and
destroying manmade structures in their paths, for example, the Big
Thompson flood of 1976. In many parts of the United States large rivers
usually flood as the result of general rains, snow melt, or hurricanes;
but small streams may have quick, localized floods from summer
thunderstorms. Long continued precipitation can raise groundwater,
inundate basements, and infiltrate sewers. In California, particularly,
mud flows caused by heavy rains on bare land previously damaged by
fires, are a problem.

Some major floods are caused by excess precipitation. The greatest flood
of record on the Missouri River in the Dakotas was due to the breaking
of an immense ice jam. The upper Snake River, in Wyoming, experienced a
tremendous flood within historic times, due to the breaking of a natural
dam formed by a landslide which had impounded the flow of a tributary
for two or three years. Other exceptional floods have been caused by the
disastrous breaching of a major dam upstream.

[Nature of the Problem]{.underline}

Unlike many other disasters, floods occur in areas which can be defined
with a fair degree of certainty. It is, therefore, theoretically
possible to avoid catastrophic flood damage either by not building in
these areas or by designing developments to survive floods. For a
variety of reasons, these seemingly simple expedients are not
effectively practiced in the United States and flood damages continue to
increase. In fact, population migration and development are important
factors in our worsening flood experience.

A major cause of flood damage is the continued migration to floodplains
and coastal shorelines. Some people freely choose to live in areas that
flood frequently. Others move from another city or state and unknowingly
settle on floodplains. Developers often build in flood prone areas and
sell the homes to people who have no knowledge of the local flood
hazards. When floods strike, these people are usually helped to rebuild.
Unfortunately, many homes and businesses are rebuilt on the same
floodplain, often with the encouragement and assistance of relief
programs funded by tax dollars and/or public contributions.

Flood damage potential may be increased by structural flood control
measures which are misused or misunderstood. For example, many levees
were built to protect farmland which subsequently was urbanized.
Although these levees provided adequate protection to farmland, they
were not designed to protect homes which represent a much larger and
more valuable investment. In other cases, the presence of a dam miles
upstream may lead people to believe that their homes are protected from
all floods, when in reality the dam could do little more than lower
flood crests. Even properly designed flood control works can lead to
increased damages by encouraging development that will be inundated when
the design flood is exceeded.

Another major aspect of the flood problem is modern man\'s ability to
alter hydrologic characteristics. Urbanization can change runoff
patterns so that both the height of, and area covered by, floods
increase downstream. Encroachment on valley storage by levees, bridges,
fill for buildings, navigation facilities, and other structures can
alter the height and duration of floods. Drainage, channelization,
forestry, and agricultural practices can all alter a watershed so that
downstream flood conditions change. Such alterations in a basin\'s
hydrologic regimen can increase the risk of damage to structures that
originally were designed and located to minimize flood damage.

It is not practical to plan development for unpredictable super floods
which may occur once or twice in a millennium. Such floods are usually
the products of rare phenomena, and it is not economically feasible to
protect against them except for highly sensitive or vital facilities.
However, the ravages of such floods are reduced by proper planning and
timely warning.

Levees may fail from overtopping or by being breached. As in the case of
dams, levee failures may be caused by inadequacies of design,
construction, or maintenance, or by a flood larger than the design
flood. The interior drainage arrangements in a levee area may also fail
or prove inadequate due to acts of commission or omission by man. In
some cases, flooding and flood damages may be attributable to
insufficient channel capacity of either improved or unimproved channels
which in turn may be due to human rather than natural causes. In
hydraulically improved channels, including diversion channels, faulty
maintenance is a common cause of inadequacy. Examples are failure to
provide periodic dredging, protection of banks, or removal of
obstructions.

Dams built for any purpose may fail for reasons ranging from design,
construction and operational inadequacies, to flood events larger than
the design flood. Whatever the cause, a dam failure can result in
flooding downstream, sometimes with catastrophic effects. Damages are
usually much worse than before the dam was built because during the
existence of the dam, the developments in the floodplain below will have
adjusted to a regulated stream regimen that would safely accommodate
more development than was feasible without the dam.

[Benefits of Flooding and Open-space Floodplains]{.underline}

Although flooding is usually considered a problem, in the appropriate
location it has natural benefits including sediment deposition. Benefits
of open-space floodplains relate to water quantity, water quality,
asthetics, and to recreational and resource values.

The benefits of flooding and open-space floodplains include the natural
storage of floodwaters, filtering or dilution of pollutants which enter
the waterways, flushing of nutrients in river systems, preserving of
wetlands, decreasing runoff having direct access to the waterway,
enhancing of recreational opportunities, recharging of groundwater, and
maintaining the river ecosystem by providing breeding, nesting, feeding
and nursery areas for fish, shell fish, migrating waterfowl, and others.

[Flooding in Coastal Areas]{.underline}

Coastal flooding by salt water is usually caused by a combination of
circumstances that may include astronomical tides, storm surges, or
tsunamis. It may be exacerbated by general land subsidence, erosion of
protective barriers, coastal developments, and by the simultaneous
occurrence of a river flood.

Certain types of shorelines or bays are more likely to be flooded than
others. Coasts that are only a few feet above sea level, and which may
also be near river mouths, are susceptible to both salt water and fresh
water flooding. This is especially true of the gulf coast and east
coasts where high winds can blow shoal waters ashore. Also more flood
prone are cities at the apex of narrowing bays which increase the height
of a mass of entering water, such as at Providence, R.I. Coastal cities
or locations such as Hilo, Hawaii, have learned by experience that they
are subject to tsunami flooding.

These components of coastal flooding need to be evaluated separately,
but they can be additive in accordance with local circumstances.

[Tides]{.underline} - Tides are long period waves with crests on
opposite sides of the earth that are supported by the difference in
gravitational attraction of the sun and moon on the solid earth and the
water of the ocean. The earth turns beneath these waves and we call the
crests high tide and the troughs low tide. On most coasts there are two
high tides a day spaced hours and 25 minutes apart, half the lunar day.
The two high tides are always the same height because of the moon^1^s
eliptical orbit about the and because the plane of the moon\'s orbit is
not perpendicular to the earth\'s axis of rotation. Moreover, twice a
year the sun, earth, and moon are in line at the same time the moon is
closest. This causes the highest tides of the year.

Tides are predictable with accuracy and the times and heights of high
tide can be forecast years in advance. They are not, by themselves, a
source of flooding; but when high tides coincide with other causes of
high water coastal flooding can occur.

[Storms and Hurricanes]{.underline} - Storms at sea can cause a rise in
the height of coastal waters, usually called a storm tide or storm
surge, in several ways. First, storms are usually associated with abrupt
changes in barometric pressure. Low pressure indicates an approaching
storm. Sea level rises about one foot for an atmospheric pressure drop
of one inch of mercury.

Second, if the wind blows toward (or parallel to) the coast it pushes
water ahead of it. This is partly the frictional drag of the wind on the
sea surface and partly the \"mass transport\" of water in the waves
raised by the wind. This is especially important where there are wide
shallow areas just offshore as in the Gulf of Mexico.

Storms also may have other effects, sometimes overlooked. On top of the
generally higher level of the sea there are storm waves which break as
they move into shallow water. These can be exceedingly destructive
because of the violent horizontal motion of the water which is quite
different from a simple vertical rise of water. In addition, the
corrosive effect of sea water, salt water, on machinery is far greater
than that of fresh water, and the effect of the salt on land plants is
very damaging.

The rise of water caused by extratropical storms and hurricanes can be
forecast, but not far in advance or with as great an accuracy as tides.
The National Weather Service has operational forecast techniques for
storm surges. Furthermore, it is possible to set up sea level measuring
stations well offshore that can give a few hours warning of an impending
rise. This has been, or is being, done in the Adriatic for Venice and in
the North Sea for London which have similar problems with storm tides.

The U.S. has a long history of coastal flooding by storm tides or surges
that go back well before the Galveston flood of 1900 when a hurricane
raised the water level 15 feet above the high tide level. Storm waves,
atop the surge, demolished the city and 5000 people drowned. Many
hurricanes since, including Carla in 1961, Betsy in 1965, and Camille in
1969, also did considerable damage along the gulf coast. Hurricane Carol
caused \$41,000,000 damage to Providence, R.I., at the head of
Narraganset Bay. Extratropical storms also have caused severe flooding
such as in February 1978, March 1962, November 1963, and November 1950.
Generally, hurricane and storm surges are an east coast, gulf coast
problem.

[Tsunamis]{.underline} - Tsunamis are long period, 10-20 minute, waves
usually set in motion by undersea earthquakes or landslides. They are
also known as seismic sea waves or tidal waves. As a result of some
crustal disturbance that gives a vertical impulse to the sea surface,
waves are generated. These waves travel long distances at high speeds,
up to 600 miles an hour in the Pacific Basin, with little loss of
energy. In deep water the wave front or crest is not discernable but
when these waves enter shoal waters of the continental shelf their
height is greatly amplified. Usually the first indication to watchers on
the shore is a slowly receding sea level. That is, the trough of the
wave arrives first and areas of bottom never before seen are exposed;
sometimes curious onlookers unwisely walk out to investigate. Then, in a
few minutes, the crest arrives; it may be a large breaking wave. Usually
three to six high waves are included although the disturbance may
continue for some time.

The crest of a tsunami and the mass of the water behind it have
considerable shoreward velocity quite capable of smashing or moving
whole blocks of buildings Photos of Hilo, Hawaii, after the tsunami of
May 23, 1960, show lines of houses cast like driftwood along a high
water mark.

The Pacific coast of the U.S., especially including Hawaii and Alaska,
is most likely to be affected by tsunamis,but they can occur in any sea.
Generally, points facing into tsunamis and bays open to them are hardest
hit.

[Land Subsidence]{.underline} - The subsidence of coastal land is
usually a slow process, but on some occasions it can happen in a
relatively short time. There are three main causes. Rocks along a
coastline may be moved by tectonic forces, causing damage rapidly by an
earthquake, as at Anchorage, Alaska, or more slowly over a period of
several decades.

Materials on coasts made of soft sediments, such as sands or muds, may
be slowly compacting into rock as gravity squeezes water from the
interstices between the mineral grains. This may be happening in parts
of the Mississippi Delta and the area at the head of Galveston Bay,
Texas. Rapid shaking of soft ground can cause it to liquify, becoming
thixatropic. The famous pirate city of Port Royal, Jamaica, sank beneath
the sea in a few moments because of this effect. Earthquakes can also
cause major changes in soft sediments.

The extraction of water, oil, or gas from underground formations lowers
the surface of the ground. In Long Beach, California, parts of the
harbor area sank over 20 feet, putting the old ground surface well below
sea level.

It is likely that these types of settling, or their possibility, would
be known to local inhabitants and could be taken into account in coastal
development.

[Seiches]{.underline} - A seiche is a wave trapped in a basin. After
cessation of the originating force, the water continues to slosh back
and forth from end to end or side to side at a speed controlled by the
depth of water. Seiching in lakes is quite common but only rarely does
the sloshing water rise high enough to cause a flood.

Usually seiches are set in motion when the atmospheric pressure on one
end of the lake is different from that on the other as, for example,
when a storm or severe weather squall line passes over one end.

Seiching formerly caused flooding around Lake Okechobee, Florida, before
a surrounding dike was built. Seiching on the Great Lakes is common but
usually not of damaging extent.

[Sea level rise]{.underline} - World wide sea level changes as ice is
added to or removed from the polar ice caps. It has not changed
appreciably in about 4000 years, before which it was much lower, and it
is not likely to rise significantly within the foreseeable future. The
average rate of rise from 1940 to 1973 has been estimated to be 1.5 mm
per year.

[Effects of Encroachment and Urbanization]{.underline}

[Flood Magnitude and Timing]{.underline}

Much research and observation have documented instances in which
development of land has increased flooding downstream. Whether this is
true for agriculture depends largely upon soil and water conservation
practices employed, but it is almost always true for high density
residential, industrial, and commercial development. It has been found
generally that after urbanization peak discharge for small floods
exceeds those existing prior to development by two to six times with a
larger volume of runoff. For larger floods the effects, although
considerable, are proportionately much less. The increase in extent of
impervious the rate of runoff. direct-connected to many country roads,
flooding due to development results mainly from the area created which
prevents infiltration and expedites Impervious areas increase runoff
much more if they are drainage channels than if, as with isolated roofs
and the runoff drains overland over pervious surfaces before entering a
channel. Therefore, the building of curbs, gutters, and storm sewers in
a development considerably accentuates the effects of a given extent of
total impervious surface.

[Debris]{.underline}

Debris movement is a particular phenomenon of floods. To natural debris
of leaves and fallen trees are added cultural debris of astonishing
variety in urban channels. Old automobile tires and shopping carts may
be present in quantity. Rock, broken concrete slabs, discarded sheet
metal, and old asphalt pavement are pushed in from the side, either to
prevent erosion of the bank or just to get rid of the material. Smaller
trash, paper, grass clipping, cut branches, and sometimes garbage\--may
be thrown over the bank. Unless a community makes a special effort,
stream channels can become the depository for much unwanted solid and
liquid waste of all kinds.

[Pollution from Stormwater]{.underline}

Stormwater runoff from both urban and rural sources merits attention. It
is during floods that streams which are normally restricted to channels
invade the wider landscape. People are exposed to unaccustomed health
hazards in their homes and places of work. Water supplies originating
from both surface and ground sources are vulnerable to contamination and
may require special disinfection before use.

[Channel Erosion]{.underline}

Increases in peak rates and total amounts of runoff resulting from
urbanization increase the tendency of a stream to erode its bed and
banks. With rare exceptions, erosion of all streams in their natural
condition was relatively stable, with slopes appropriate to the amount
of flood flow and the material in which the channel was incised, and
with certain other influences such as vegetation.

In these urbanizing areas, as impervious surfaces increase, the erosive
powers of the stream may be more than doubled, in terms of the power to
move quantities of bed load of a given size. The stream bed widens as
erosion attacks the convex as well as the concave bank. The bottom
deepens, and the erosion tendency moves upstream. Tons of heavy bed load
may be deposited further downstream in reaches of flatter slope where it
causes increased flood heights. Masonry walls built to protect the banks
of streams may be undermined and fall inward toward the channel.

[Effect of Changing Climatic Conditions]{.underline}

Climatic change has been a popular subject for discussion in rec\~i\~
years as the National Climate Program has developed. This subject was
specifically cited in the Congressional directive to the National
Science Foundation in establishing the current study.

Much attention regarding climate change is directed to piedicting
whether the climate is becoming wetter or drier, colder or
hotter\--without clear resolution among scientific investigators.
0ff-setting factors which can result in climate change are recognized,
but which of these will dominate remains conjecture.

Two significant factors can be cited relative to flood hazard
mitigation. Within the period of measured precipitation and runoff, wide
variations of climatic conditions exist. Geologic and other studies add
strong evidence of even wider fluctuations of climate for thousands of
years past. There is no reason to believe that such wide oscillations in
climate will not continue, and flood mitigation strategies should
consider them.

While studies and arguments continue regarding continental and global
climate change, strong evidence indicates that the climate of storm
rainfall over and downwind of major cities has resulted in greater
flooding and resulting damage there than in less populous areas.

During the past 20 years, study of limited historical weather records
shows evidence of changes in precipitation in cities and in areas
extending beyond in a downwind direction. Studies of nine American
cities, in different climatic areas and with different industrial
complexes, indicated that the seven largest\--Chicago, St. Louis,
Detroit, Washington, Houston, New Orleans, and Cleveland\--provided
evidence of a change in both cold and warm season precipitation. Also,
it was found that the urban effect might account for substantial
increases in incidence of thunderstorms, hailstorms, and heavy
rainstorms downwind of large cities. Increases in these events occurred
at very different types of cities, such as Washington, D.C., and
Chicago, but occurred only at cities of more than 1,000,000 population.

An intensive study at St. Louis was undertaken to obtain a better
definition of urban precipitation anomalies and to discover their causes
and impacts. Associated with the added storminess and heavier rainfall
were many additional costs. Fifteen impacts resulting from heavier
rainfalls in the St. Louis study were classed as involving major costs.
For instance, soil erosion was calculated to be 34 percent more than
would occur without the anomalous heavy rains. The major floodplain east
of St. Louis contains many suburban areas and many transportatio\~n
links, and the increased heavy rains resulted in a 20 percent increase
in automobile accidents. Sewage and water quality problems of the
suburban communities have been aggravated by a 40 percent increase in
surcharges or by bypasses of suburban waste water treatment plants
resulting from the greater number of the urban-induced heavy rain
events. As exemplified by the St. Louis study, the inadvertent
modification of climate near large urban centers requires the attention
of all concerned with stormwater management, and is a fruitful field for
further studies.

III FLOOD DAMAGES: TRENDS AND

GEOGRAPHICAL DISTRIBUTION

Flood losses in the United States are grim, indeed, and are projected to
increase. The Water Resources Council (WRC) estimates that such losses
were \$3,400,000,000 in 1975, and that the potential loss will increase
to \$4,300,000,000 in 1975 dollars by the year 2000. NOAA has estimated
that average annual losses in the U.S, during this century, have been
increasing at about 4 percent per year in real terms. Comparable figures
averaged only \$104,000,000 from 1926 to 1940. These figures probably
are understated because the federal agencies never have been able to
obtain accurate estimates, and the WRC refers to them as approximations.
The trend of flood losses in the United States is shown in Figure 1.

According to the WRC, agriculture accounted for 48 percent of the 1975
potential losses, urban areas 22 percent, and other areas including
public lands, public buildings, mining, utilities, and rural industries
were 19 percent. By the year 2000, agricultural losses are projected to
rise slightly in dollar value but drop to 40 percent of the total. Urban
losses are projected to rise to 36 percent and other areas to 23 percent
of probable flood losses in the year 2000.

Further costs are incurred, primarily by federal agencies, to combat and
reduce losses. Again such data are difficult to isolate, but the
following is a partial list for fiscal year 1980.

The above costs do not include those of the Soil Conservation Service
and numerous other federal, state, and local agencies, as well as those
of private individuals and groups which are not reimbursed.

Flooding Along Streams

Flooding occurs in all regions of the United States. It is a problem on
floodplains because people historically have used river systems for
transportation and life support systems. There is also an aesthetic
appeal which makes these flood prone areas among the most attractive
places in which to live or work. Both urban and rural communities are
vulnerable.

The distribution of flooding, as indicated by total land area flooded
and by the population affected during flooding, is shown on Figure 2.
That map of the United States depicted by river basins, indicates that
the largest acreages subject to riverine flooding are in the Missouri,
Arkansas-White-Red, Lower Mississippi, and South Atlantic-Gulf regions.

The percentage of a given drainage basin which is subject to inundation
varies considerably, depending upon the particular stream, the
topography of the area, gradient of the stream, and other factors. In
parts of New England and dry parts of Wyoming only a very minor portion
of land area is inundated. In the Chicago area approximately 15 percent
is subject to inundation, and in the low areas of Florida and Louisiana
nearly all of the land may be inundated at times.

Development and Population

Development and population are currently concentrated in flood prone
areas along the northeast, Ohio Basin, Great Lakes, and California water
resource regions. Along other portions of the nation^'^s floodplains,
considerable farming occurs in river bottoms with little population in
the risk category. This is particularly true in the southern and western
Mississippi regions. About 7 percent of the 48 contiguous states is in
the 100-year flood zone. The following additional characteristics are
supplied by James E. Goddard:

Over 200,000 square miles in the nation are subject to flooding, an area
equal to the combined size of California and Ohio. One-sixth of all
urban areas are in the floodplain which is subject to flooding on the
average once in 100 years. There have been estimated to be more than
20,000 flood prone communities in the United States.

The mountainous areas of the Appalachian regions present unique problems
for growing populations since suitable space for expanding population is
minimal.

Trends

Population and property at risk under current policies will continue to
increase. This situation could be exacerbated by demographic trends if
people continue to move into flood hazard areas at an increasing rate,
despite floodplain regulations. This is evident by the recent upward
trend in damages over the past several decades. As our development
patterns continue to remove permeable soil and replace it with
impermeable roofs and pavements, increased runoff will result in
increased damage and loss of life potentials from floods. All of these
trends point toward more disasters, more loss of life, and higher public
expenditures, unless flood hazard mitigation programs become more
successful.

A significant commitment on the part of Congress and the nation will be
needed for improvement in present flood hazard mitigation efforts which
will lead to reduction in taxpayers\' dollars for disaster relief and
other subsidized investment in the nation\'s floodplains. A major effort
is needed to stop federal investment in flood prone areas in the form of
increased economic development subsidy and also in subsidized housing
and highway construction which encourages development in highly
susceptible places such as coastal barrier islands. Also there is an
increase in flood damages on small streams and watersheds. Policies must
be implemented which regulate small watershed development. All of these
trends and factors will require a commitment for data collection, flood
hazard mitigation, and incentives to encourage nonstructural flood
damage reduction solutions.

The Economics of Coastal Areas

The elements that attract people to coastlines are economic and social.
Ports generate tremendous economic activity and stimulate huge
manufacturing infrastructures adjacent and integral to the vital
waterborne transportation system. It is no strange phenomenon that most
of \~ largest cities are either on the coasts or within relatively short
rail or water transport distances, and the seven largest cities are in
the coastal zone. Forty percent of the nation\'s industrial complexes
and 50 percent of the manufacturing facilities border on the east
coast\'s estuaries. In 1976, 53 percent of the population lived in
counties within 50 miles of a coastline. Population within this coastal
50 miles shows a density of 72 per square mile as compared to 40 per
square mile for the balance of the United States.

It cannot be inferred that the total population within this 50-mile
corridor of the nation\'s 12,383-mile coastline is subject to flooding.
Certainly it can be assumed that this is a good estimate of the
population which is potentially subject either to direct flood hazards
or to indirect economic impacts that major hurricanes, tsunamis, or
other tidal flood events can inflict. Considering the unpredictable
nature of these tidal events, their frequency, and the ever increasing
and human-created vulnerability to them, it is useful to make the point
that the flood hazard is in direct correlation, however the
quantification, with the general population of the hazard prone area.

Total investment in exploration for oil, gas, sulphur, salt, and other
minerals and mining extractives in coastal and offshore areas of the
United States is very difficult to enumerate. In Louisiana alone in
1974, outer continental shelf oil and gas production value was
\$3,155,000,000. This in turn generated an estimated \$1,823,000,000 in
economic production in all other economic sectors of the state. Thus,
the urban and industrial development attributable to offshore oil and
gas exploration is highly significant and, in practical terms,
inevitably impacts the coastal flood-plain. Louisiana is only one of
many states, and the current leading producing state, experiencing
offshore development. The energy situation foreshadows that increased
exploration, with its onshore development impacts, is likely to increase
in all coastal areas with any potential for oil and gas production,
including the northeast, California, and Alaska.

Some of the most scenic and valuable recreational areas are on coasts.
Few of us want to give up the convenience that shorefront hotels,
condominiums, restaurants, and shops provide.

In summary, an almost unlimited number and variety of attractions exist
which draw people to communities and jobs within coastal flood prone
areas.

The Coastal Setting

Barrier Islands - Barrier islands extend the length of the coastline
from Texas to Maine. These islands are formed from unconsolidated
materials by tidal and river deltaic action. They range in size from a
few yards to many miles and from totally undeveloped and isolated to
heavily urbanized and exploited areas. The scenic beauty and rich marine
life these islands exhibit attract more and more people every year for
recreation and settlement. Forty barrier islands that had no urban
acreage in 1950 had undergone development by 1973. In their natural
state, these islands are subject to readjustment with the forces of
nature. Periodically, barrier islands vanish or materialize from nowhere
as a result of a single powerful storm. One such event occurred with the
complete disappearance of an inhabited island off Louisiana\'s coast
early in this century.

Effects of urbanization on these islands can be dramatic. Shifting sands
can accrete or erode, depending on the placement of a jetty, a bridge,
navigation channel, or other development. The leveling or paving of
dunes will determine the fate of property and lives during subsequent
storm events. Barrier islands together with coastal wetlands represent
the first line of natural defense against oncoming tidal storms. These
islands are geographically placed in the position of greatest
vulnerability to oncoming storms and can significantly buffer inland
communities from the full force of hurricane waves.

To protect and enhance their uniqueness and value, the barrier islands
justify man\'s special attention. Development in many instances cannot
be prevented or eliminated, but their recreational, intrinsic, and
strategic worth is such that intensive and committed policies consistent
with the preservation and enhancement of barrier islands is imperative.

Beaches - Beaches vary in size, form, and composition. Sand beaches can
stretch inland for miles with the aid of prevailing winds and currents,
or they can be so narrow that they barely provide for sunbathers.

Beaches are a geologic creation of upland erosion and alluviation. Their
sand particles and miniature mountain dunes are in constant flux as are
barrier islands, but unless interfered with by man, most of the movement
is a steady littoral shift of sand ripples, bars, and spits. Beach
erosion can be costly in terms of loss in recreational resources or
storm buffering and in expensive erosion preventive measures. Recreation
has become the leading economic activity of the coast, increasing by 76
percent in the past 15 years and accounting for more than
\$15,000,000,000 spent in a single recent year. As a result of massive
hotel construction on beaches, loss of beach area has received more
attention. Society\'s persistence in overdeveloping beachfront resources
increases the risk of economic and life loss. This problem is not
confined to the east and gulf coasts but is serious in the Pacific area,
as has been reflected by Hawaii and California coastal zone management
policies for several years.

Coastal Wetlands - By many scientific and lay testaments, coastal
wetlands are the most biologically productive and diverse of all earth
ecological communities. It is here that terrestrial and marine life and
interact in highly complex and interrelated processes.

Wetlands are invaluable assets for fisheries production, storm tidal
buffering, hunting, recreation, and other exploitation of their
resources. This value is not fully appreciated by the general public.
One reason may be that there is a very pronounced and irreconcilable
contrast; the wetlands benefit from and are dependent on regular
flooding events; larger floods have highly destructive impacts on both
man and habitats.

Thus, in coastal wetland floodplains as in riverine settings, policies
to mitigate and protect against flood hazards must be formulated with
forethought and comprehensive planning which adequately recognizes the
interrelationships and complex dynamics of floodplains and their human
inhabitants.

The History of Coastal Floods

Hurricanes and other coastal floods have always been periodic
atmospheric events with impacts along North American shores. Between
1900 and 1977, an average of two major hurricanes every three years made
landfall somewhere along the U.S. gulf or Atlantic coasts.

The costliest hurricanes, for the most part, have been recent events.
Figure 3 expresses this with a scatter diagram showing the trend in
damage assessments increasing in recent years. Few of the deadliest
hurricanes (Figure 4) have occurred in the past 20 years in contrast to
most of the costliest hurricanes. This is largely due to successful
evacuation of the public just before the storm\'s arrival.

Inferences can be made about the inverse association of costliest and
deadliest hurricanes. The death rate may have been decreasing as a
result of improved early warning systems and civil defense programs. It
would be dangerous to assume reduced incidences of death will continue,
however, because continuing development on the coastline augments the
vulnerability of populations living there.

Increasing costs of floods also can be associated with increased
development. This fact implies that damage costs may grow due to rising
values of construction and added exposure.

Death rates and costs apparently are not related to storm intensity, and
Figure 5 indicates that the intensity of storm seems to be distributed
equally over time.

The National Weather Service and other agencies are concerned about what
they consider to be citizen complacency and lack of perception about
hurricane risk. In 1970, according to Hebert and Taylor, 80 percent of
coastal residents from Texas to Maine had never experienced a direct hit
by a major hurricane because they were new to the coastal region. In the
nearly two decades between 1960 and 1977 an anomalous drop in hurricane
frequencies occurred. This phenomenon combined with naivete of
inexperienced residents regarding hurricane risk may be creating a false
sense of security for the public.

The most recent evidence of hurricane flood impacts was provided by
Hurricane Frederick which hit Mobile Bay late in 1979. A complete
assessment of the damage impacts is not yet available, but it is certain
to be included as a major hurricane. Political and economic pressures
already are being applied to redevelop the hardest hit areas of Gulf
Shores and Dauphin Island.

Frequency and Prediction

The previous discussion on historic events and accompanying Figures 3,
4, and 5 provide a general understanding of historic hurricane and tidal
flood frequencies. Additionally, Figure 6 depicts frequencies of
hurricanes impacting the gulf coast since 1831. This is an incomplete
illustration, however, when one recognizes that many storms of less than
hurricane strength result in extensive coastal flooding.

Other Coastal Floods

It should not be concluded that hurricanes are the only causes of
coastal floods. They are discussed first because they are the most
notorious. Dramatic flooding incidents also can be the result of
geologic events such as tsunamis and atmospheric events such as intense
rainfall leading to flash flooding and perigean spring tides. Flash
flooding is discussed elsewhere and is not specifically coastal in
character.

Over 100 documented cases of severe tidal flooding occurred along both
Atlantic and Pacific coasts in a 341-year period resulting from the
Perigee-Syzygy effect caused by alignment of sun, moon, and earth. In
1962 a storm driven Perigean tide hit the entire mid-Atlantic coastline,
and, extending over a 65-hour period, caused \$5,000,000,000 in property
damage and was responsible for 40 deaths. Other severe examples occurred
along the Atlantic on December 30, 1959, March 4-5, 1931, and April
10-12, 1918. All points on the Pacific coast experienced Perigean tides
on March 6, 1970, February 3-4, 1958, and January 3-5, 1939. Floodings
were experienced [simultaneously on both coastlines]{.underline} on
December 11, 1973, on March 26, 1971, and on January 6, 1931.

[IV APPROACHES TO FLOOD MITIGATION]{.underline}

[Adjustment Options]{.underline}

Man must move toward a balance with nature, recognizing that he cannot
and need not control all flooding, yet he can exercise a measure of
control and also can adjust his actions to minimize losses.

Three general types of adjustments are available: [modifying the
hazard]{.underline}, by the physical means of dams, levees, land
treatment, channel improvements, and others; [moderating the
impacts]{.underline}, by flood insurance, floodproofing, relief and
rehabilitation, warning systems, and others; [reducing the
risk]{.underline}, by reduction of hazardous uses of floodplains through
floodplain management techniques.

[Modifying the Hazard]{.underline}

[Storage Reservoirs]{.underline}

A storage reservoir is a stream impoundment with controllable outlets.
Such storage areas can be created by dams designed primarily to
ameliorate flood problems downstream or designed to serve additional
purposes as for water supply, hydro-power generation, recreation and
other activities.

Controllable storage capacity for flood control affords flexibility for
effective operation over a wide range of conditions, seasonally and
annually, short-range and long-range. Selection of an optimum capacity
can be achieved with reasonable approximation insofar as monetary
benefits and costs are involved, but adequate consideration of
nonmonetary factors which may be important or paramount is difficult.

Both adequate storage capacity and ample emergency spillway capacity are
essential to minimize the possibility of failure of the dam.

[Detention Basins]{.underline}

Detention basins typically are small impoundments with uncontrolled
outlets. They may be created by building a dam, by embankments, by
excavation, or by a combination of these. Usually they are designed to
retard the

water in the basin to achieve a reduction in the peak flood stage
downstream. They also may be designed to improve infiltration for
recharge of acquifers. A developing concept is to detain runoff
sufficiently to permit settlement of sediment thus reducing particulate
pollution. This may provide a possible approach to the vexing problem of
controlling nonpoint pollution.

Detention basins may mitigate flood damages at relatively low cost, but
the beneficial effect does not extend far below the impoundment;
therefore detention basins should not be relied upon to provide an
appreciable improvement at major flood damage centers on major rivers.

[Levees]{.underline}

Levees are structures constructed on the floodplain to prevent the
streamflow from extending further in a landward direction. Areas
protected by levees are provided with interior drainage arrangements
such as ponding and pumping to handle inflows to the protected area from
sources landward of the levee.

A flood wall is a more compact stream channel confinement structure than
the familiar levee. It is usually a reinforced concrete retaining wall
designed to confine the stream channel where there are space
limitations; it is generally placed at the stream bank.

Calculation of the flood elevation for which a levee will provide
protection may be a relatively simple problem in a compact area where
the source of the flood problem is related to one or two simple streams;
or it may become very complex, as in the lower Mississippi area where
possible flood elevations are affected by what happens in a vast
drainage area comprising nearly two-thirds of the 48 contiguous states.

Levees and walls may be designed and built to use emergency spillways or
removable plugs during extreme floods.

[Channel Modifications]{.underline}

Stream channels may be modified by deepening, widening, straightening,
or by removal of obstructions to enhance the capacity of the stream
channel to carry higher flows thereby reducing the height, extent, or
duration of overflow to the floodplain.

Channel modifications may be a direct way to deal with specific
localized flood problems, as in congested developed areas. They also may
be useful or necessary as an adjunct to other structural measures for
flood control, as below reservoirs where changes may be needed to
accommodate the modified regimen of flow or in levied areas where the
amount and velocity of streamflow may threaten the stability of the
levee.

Channel modifications cause changes in the natural regimen of streams
and may have adverse effects at site and downstream. For example,
channel modifications almost always reduce natural valley storage and
increase flooding downstream.

[Land Treatment]{.underline}

Land treatment, often called watershed improvement, encompasses those
measures that can be taken to alter the physical characteristics of the
land to achieve a beneficial effect in reducing the flood hazard
downstream. Those measures include improving or preserving vegetative
cover, regarding, terracing, and those which increase infiltration or
delay runoff to the stream channel such as wise management of forests
and open range.

Depending on the nature of the flood problem downstream, land treatment
usually has a beneficial flood control effect on all but sustained high
flows. Other significant benefits may include reducing erosion,
maintaining groundwater levels, and recharging aquifers.

[Emergency Flood Fighting]{.underline}

Relatively few types of structural measures can be taken on an emergency
basis before or during a flood event. Sandbagging is one means of adding
a few feet to the effective height of existing levees for additional
temporary protection. It also can be used to create a temporary
protective barrier at unprotected low points. Flashboards or other
structural devices for providing temporary additional elevation may be
feasible on flood walls or in limited specific areas. Emergency pumping
may be necessary to maintain satisfactory interior drainage behind
levees or to remove water from basements or other limited areas where
water normally drainable may accumulate during floods.

The usefulness of emergency measures can be enhanced by advance
preparation of flood emergency manuals which identify responsibility and
capability of organizations and specific individuals who can help in
flood emergencies. Sandbags can be stockpiled and sources of material
and equipment can be earmarked to help make best use of all resources
during flood emergencies.

[Moderating the Impacts]{.underline}

[Flood Insurance]{.underline}

In effect for little more than a decade, the National Flood Insurance
Program (NFIP) has become an important element in the nation\'s flood
loss reduction effort, bringing into play four nonstructural approaches
to the problem: insurance, floodplain regulation, floodproofing, and
land acquisition.

The private insurance industry abandoned flood insurance except for
coverage on automobiles and mobile homes when insurance companies
suffered catastrophic losses following major flooding in the late 1920s.
In 1956, after major flooding in the northeast, Congress authorized a
National Flood Insurance Program but never funded it. Nine years later,
following a series of hurricanes that caused extensive flooding and a
450 percent increase in federal disaster assistance the Department of
Housing and Urban Development undertook a study of existing flood
related policies and recommended to the Congress a federal flood
insurance program that included steps to discourage additional building
in flood hazard areas.

Key recommendations included adoption of floodplain regulation as a
requirement before communities could become eligible for the sale of
flood insurance, and a dual rate structure insuring existing buildings
at subsidized rates and new buildings at actuarial rates based on the
actual extent of hazard to which they were exposed.

The bill that emerged as the National Flood Insurance Act of 1968 took
effect exceedingly slowly. During the first year, only four communities
joined the program, and only 20 policies were purchased. One deterrent
was the lack of flood insurance rate maps that communities could use to
determine their flood related land-use ordinances. Consequently, in
December 1969, Congress amended the law to permit communities to join
the subsidized \"emergency\" program pending completion of the detailed
mapping. Program growth continued to lag. By 1973 only 3000 of the
approximately 20,000 communities with potential flood problems had
joined and only 300,000 policies were in effect.

When the tragic flood killed 238 people in Rapid City, South Dakota,. in
June 1972 only 29 policies were in effect even though the city had a
known flood history. Sixteen days later, when tropical storm Agnes sent
floodwaters raging through eastern Pennsylvania, only 683 policies were
in effect in the state, and only two or those were in Wilkes-Barre,
hardest hit community in the state. Subsequently, Wilkes-Barre residents
complained they were not aware that flood insurance was available.

Slow growth of the program was attributed to lack of public awareness,
lack of insurance agent motivation and sales effort, failure of local
authorities to seek eligibility, and general lack of concern about flood
problems. In December 1973, the Congress moved to strengthen the
National Flood Insurance Program (NFIP) by passing the Flood Disaster
Protection Act which required flood insurance participation before a
community could get any form 4 of federal or federally related financial
assistance for land acquisition or construction in any designated flood
hazard area. Nor could flood victims receive any form of federally
funded relief or loans if they were not insured or if the community was
not in the NFIP even though its hazards had been formally identified and
mapped. Even though these mandatory factors were enacted, it was
anticipated by skeptics that they would be waived by special
Congressional action if flood victims were actually denied assistance
because their communities were not in the program. Just this did happen,
in New Jersey, and there was special Congressional action. In other
cases the \'4 sanctions have generally been applied.

Since that time, there has been a steady growth of the program, although
a few communities have dropped out rather than comply with the
floodplain regulation requirements or floodproofing building
requirements, and there have been numerous appeals against specific map
delineations or ground flood elevation requirements, and Congress in
1977 weakened some of the mandatory requirements related to issuance of
mortgages by banks and loans by federally related lending institutions
in the identified flood hazard area of nonparticipating communities.
Almost 1,800,000 policies were in effect in 16,732 communities at the
end of 1979. Coverage totaled almost \$73,000, 000,000 in face value.
Much of this coverage was achieved through the requirement that flood
victims purchase the policies to get federally funded relief or disaster
loans; also there has been a lot of sales promotion in areas with
current potential flood threats. The program still can expand; FIA
projects a market for 7,000,000 policies.

Concerning insurance aspects of the program, NFIP now is the single
largest nonrepayable resource for flood victims. In Calendar Year 1979,
NFIP paid \$427,483,256 to 66,175 claimants. During this same year,
individual assistance programs funded through the President\'s Disaster
Fund provided approximately \$229,500,000 in various forms of help after
the President declared 39 major disasters involving flooding. Only
disaster [loans]{.underline} from the Small Business Administration and
Farmers Home Administration exceeded the federally subsidized insurance
program as a recovery resource, with almost \$1,800,000,000 in loans
going to about 103,000 eligible borrowers.

The patterns of claims payments indicates most of the payments occurred
at the time of a single disaster or series of floods that followed
earlier ones in which recipients of government aid were required to buy
flood insurance against the future.

NFIP is more than just a program for insurance claims as it encompasses
floodplain regulation, floodproofing, and land acquisition. Progress in
these other categories has been much slower, as they require State,
county, or local political entities to take the major actions concerned.
It is estimated that as of late 1979 only 4800 communities had adopted
land-use regulations required for participation in the regular program.
The other communities in the program remain eligible for subsidized
coverage without moving significantly toward managing their floodplains.

To encourage more action toward local floodplain management, NFIP is
redirecting some of its efforts. In mapping over 16,000 community flood
hazard areas, FIA had assumed that any area subject to 100-year flooding
is a special flood hazard area regardless of the amount of development
therein. Therefore, NFIP, in order to acknowledge these phenomena, to
meet statutory deadlines, and to reduce program costs, says certain
initiatives have been undertaken to redirect the program. These are
included: accelerated conversion of minimally flood prone communities
into the Regular Program (where actuarial rates will be levied against
new construction); refocussed priority on communities with development
in their floodplains and/or potential for floodplain development;
technical assistance to states and local communities; state assistance;
and coordination of federal efforts in flood hazard mitigation.

Approximately 9800 communities with minimal flood problems have been
identified for accelerated conversion into the Regular Program, whereas
8600 communities with significant building or potential for building in
the flood-plains will be the principal focus of the redirected NFIP
priorities. These communities will get detailed flood hazard studies,
rate maps and data essential to floodplain management, and a broad
panoply of technical assistance aimed at integrating floodplain
management into total community planning, management, and development
contexts. It should be noted that \$4,600,000 has been made available
for this State Assistance Program from FY 1980 appropriations.

Although Section 1362 of the 1968 National Flood Insurance Act permits
FIA to enter into negotiations to voluntarily acquire flood damaged
property covered by flood insurance, the section was not funded prior to
FY 1980. With \$5,400,000 appropriated this fiscal year, the 1362
acquisition program is now being implemented.

This past year FIA has been successful in relocating flood damaged
structures out of the floodplain. FIA now has a mechanism which may
allow some individuals to accomplish permanent relocation out of the
floodplain. This mechanism, referred to as a Constructive Total Loss
(CTL) declaration can be authorized solely by the Federal Insurance
Administrator. For consideration prior to final approval, those
structures eligible for this declaration must have been damaged while a
Standard Flood Insurance Policy was in force and, as a result of the
nature of those damages, are precluded from repair or reconstruction
because of the denial of the local community to approve a building
permit application. This CTL final settlement under the flood insurance
policy may allow an insured homeowner to be paid up to the full face
value of the policy in force at the time of the subject loss (minus any
claim payment already made for the most recent damages). This additional
amount may allow a homeowner to pay for the cost of relocation. A
relocation usually will include the purchase of either a new or an
existing structure outside the floodplain and physically moving the
individual\'s home to a new site. As of February 25, 1980, there have
been 41 such constructive total loss payments, all in Texas, and others
are under consideration. To fully effect this approach, the FIA is
working with the Small Business Administration to amend various
regulations that in the past actually have forced people to remain in
the floodplains if they wanted a low interest disaster loan or that have
prevented use of such loans for relocation purposes.

[Floodproofing]{.underline}

Floodproofing is a method of moderating the impacts of flooding. It
provides a means to utilize lands susceptible to occasional flooding or
to protect existing structures when it is not practical or appropriate
to control flooding.

Floodproofing is a basic floodplain management criterion of the National
Flood Insurance Program (NFIP). Specifically, the NFIP mandates that
local governments must require any proposed building, residential or
nonresidential, that is to be constructed in defined flood hazard areas
to floodproof utility and sanitary facilities and to elevate the lowest
floor, including basement, to a height at or above the 100-year flood
level.

The advantages of floodproofing are that damages to structures and
contents are reduced or prevented, architectural design and construction
techniques are well-known, and the occupancy of a floodplain site and
surrounding infrastructure is allowed under controlled conditions. The
disadvantages are that larger floods can occur that rise above the
floodproofed elevation, flooding of surrounding areas still occurs with
possible damages to other facilities and services, and emergency access
can be difficult during flooding events.

Several specific floodproofing approaches have been applied to new or
existing structures and there is evidence regarding their applicability
and effectiveness. Various approaches must be evaluated based on the
site conditions; one or more may be feasible. Also, the effectiveness of
floodproof-mg measures can be enhanced when combined with other
mitigation techniques such as warning systems.

[New Structures]{.underline} - New structures can be floodproofed by
small walls or levees, elevating, or a combination of the two. Also,
proper construction materials and practices can reduce flood damages.

[Elevating a New Structure]{.underline} - Numerous residential and
commercial structures built in flood hazard areas have been elevated for
years. Methods used to elevate vary depending on aesthetics, the type
and use of the structure, availability of material, and on the nature of
the flood hazard. Various materials are commonly used: earth fill;
concrete walls; and wood, steel, concrete or masonry posts, piles, or
piers.

[Walls and Levees]{.underline} - Walls and levees can be used to protect
one or several buildings from flooding and are contrasted to flood walls
and levees *along *rivers *and *streams intended to provide more general
protection. Flood-proofing walls and levees usually are not more than
six feet high and are built to be compatible with local landscape and
aesthetics. Walls may be of brick, stone, concrete, or other material
designed to resist the lateral and uplift pressures associated with
flooding. Levees usually are constructed with an impervious inner core
to prevent seepage and with slope protection if erosion is a problem.

Walls or levees can protect property outside a structure; but they may
pose problems with internal drainage, and they may require openings
which must be closed during a flood. If the closures are manually
operated, a warning time is necessary.

[Construction Materials and Practices]{.underline} - Water resistant
materials and damage reducing construction practices are available to
protect against flooding. Generally, they are used to modify one or more
of the following areas: basements and/or first floor walls, floors, and
ceilings; structural interior walls, insulation, and outside utilities;
and electrical, heating, and air conditioning systems.

Use of construction materials and practices to reduce flood damages is
most appropriate where flooding is not severe or where this approach is
the only feasible alternative. Requirements for this procedure can be
made a part of local building codes or other building regulations.

[Existing Structures ]{.underline}- Floodproofing options for existing
structures are somewhat more constrained than for new structures. They
include temporary and permanent closures for openings, elevating, small
walls or levees, rearranging or protecting damagable property, and using
flood resistant construction materials and practices. Uses of levees and
walls, and construction materials and practices are discussed above.

[Temporary and Permanent Closures for Openings in Existing
Structures]{.underline} -Structures whose exterior is generally
impermeable to water can be made to keep flood water out by installing
watertight closures to openings such as doorways and windows. Seepage
can be reduced by applying a sealant to walls and floors and by
providing a floor drain where practical. Closures may be temporary or
permanent. Temporary closures are installed only during a flood threat
and need warning time for installation. The use of closures may be
feasible if the exterior walls are impermeable or can be made so, all
openings below the design flood level can be closed, and the structure
can withstand the anticipated hydrostatic pressures including buoyancy.

Several advantages of using temporary or permanent closures exist:

floodproofing may be done on a selective basis; it is easy and quick to
implement; and for large commercial or industrial type structures
potential benefits are high relative to the cost. Conversely, this
approach is applicable only to basementless structures with brick or
masonry type walls that can withstand hydrostatic and uplift pressures,
there is reduced likelihood of effective closure at nights and during
vacations when temporary closure is used, and a false sense of security
may induce people to stay in the building longer than they should.

[Raising Existing Structures]{.underline} - Existing structures in flood
hazard areas often can be raised in place to a higher elevation to
reduce damages from flooding. Generally, the technology exists to raise
almost any structure, but it can be costly. The lower-cost methods
usually involve structures which are accessible below the first floor
for placement of jacks and beams, are light enough to be jacked with
conventional house moving equipment, and are small enough not to have to
be partitioned.

Raising existing structures include these advantages: flood damage below
the raised first floor elevation is reduced; it is especially applicable
to single- and two-story frame structures on raised foundations;
structures can be raised to heights of nine feet; means of raising a
structure are known and contractors are available; the owner/user can
continue operation at the existing location; and flood insurance
premiums are reduced. Disadvantages of this approach are that residual
damages exist when floods exceed first floor elevation, it is generally
not feasible for structures with slab-on-grade foundations or structures
with basements, and landscaping and terracing may be necessary.

[Rearranging or Protecting Damageable Property within an Existing
Structure]{.underline} - Within an existing structure or group of
structures damageable property often can be placed in a less damageable
location or protected in place. For example, furnaces and water heaters
can be raised off the floor or be relocated to higher floors, and all
property that might be damaged by movement can be anchored.

This measure provides several advantages: most property owners can take
at least some of the necessary actions; it can be done on a per item
basis, thus allowing selective protection; and a structure can continue
to be used at its present site. Disadvantages are that damages can be
reduced only on those items which can be relocated or protected, a
potential residual damage to the structure and contents not relocated or
protected remains, and new patterns must be established for the
relocated property.

Note: The above information on floodproofing is based primarily on U.S.
Corps of Engineers \"Physical and Economic Feasibility of Non-Structural
Floodplain Management Measures\" by W. K. Johnson, March 1978.

[Relief and Rehabilitation]{.underline}

Emergency response and relief agencies believe that the relief and
rehabilitation process begins with the evacuation of actual or potential
flood victims from their homes and continues until they return home or
to permanent, alternate living arrangements and are able to resume
normal living.

Precautionary or escape evacuations usually are accomplished under the
leadership of local public safety and emergency service agencies with
appropriate technical advice from the National Weather Service, the
Corps of Engineers, or local water district officials. It is difficult
to quantify the number of evacuees resulting from floods or flood
threats. Generally, the larger numbers\-\--500,0O0 along the
Texas-Louisiana gulf coast in 1961, perhaps 200,000 along the Florida
and southeastern states Atlantic coastal areas and another 300,000 along
the Florida-to-Louisiana coasts in 1979\-\--are caused by hurricane
threats with projected coastal and lowland flooding. Red Cross
historical data show hundreds of thousands of evacuees sheltered during
widespread flooding in 1927 and 1936. In some cities, like Minot, North
Dakota, preflood evacuation has become almost a way of life, with
activities such as opening of Red Cross shelters and removal of
furniture and other possessions preorganized and routinely implemented
when the Souris River begins to rise.

Evacuation and sheltering of evacuees by the Red Cross or by friends and
relatives enhances personal safety, but except when furniture is removed
or machinery is protected by greasing or other methods and mobile homes
are towed to higher ground, the degree of property loss reduction is
minimal. Estimates of the savings in property loss reduction resulting
from such preflood actions range from about 5 to 25 percent of the
losses that otherwise might have been suffered.

Emergency Red Cross shelters are usually in churches, schools, colleges,
fairgrounds, union halls, veterans facilities, and similar public
buildings and are operated in cooperation with a variety of agencies and
groups. In modern times, rarely has it been necessary to house people in
public shelters for more than a week or two. After the 1972 Agnes floods
in Wilkes-Barre I and the 1977 Johnstown flood, small numbers of elderly
flood victims were sheltered for up to two months. The cost of such mass
care usually represents a small fraction of relief costs.

For those whose homes are damaged and who need assistance so that they
can return to their homes, and those who take up alternative quarters
while their homes are being restored or until new accommodations are
located, various assistance programs are available to meet essential
needs not covered by insurance. None of these programs will replace all
losses. These relief and rehabilitation programs are generally the same
for victims of all natural disasters, with only the National Flood
Insurance Program applying uniquely to flood or mudslide disasters.

Historically, most flood victim assistance was provided by the Red Cross
before the late 1950s and mid-1960s. The organization, acting under its
Congressional mandate as a disaster relief agency, provided initial mass
care assistance and financial aid to individuals and families for
rebuilding or repair of homes and replacement of essential household
contents, assistance with flood caused health needs, and replacement of
occupational supplies and equipment. The cost of Red Cross assistance is
borne from private contributions. Government assistance to the Red Cross
commonly has provided, without charge, government food commodities from
the Department of Agriculture and logistical support from the military
or FEMA. Until relatively recently, federally funded assistance was
primarily for the restoration of publicproperty and facilities and for
emergency services related to protecting public health and safety.

In the late 1950s, low interest Small Business Administration (SEA)
disaster loans became available to flood victims, and later, Farmers
Home Administration (FmHA) loans became available to farmers and rural
residents. As a result, Red Cross recovery assistance was developed to
supplement the victims^1\ ^borrowing abilities and other resources.
During the same period, other federally funded assistance programs
evolved: special, expedited disaster unemployment insurance for flood
victims whose jobs were affected; use of food stamps for disaster
victims; tax rebates on uncovered losses to provide flood victims with
additional cash by making the rebate from already paid taxes; aid
pertaining to existing mortages, vocational help, emergency welfare and
related activities.

The current programs were institutionalized and coordinated by the
Disaster Relief Acts of 1970 and 1974. The latter placed the reorganized
federal disaster response under the direction and coordination of the
Federal Disaster Assistance Administration (FDAA) in HUD. The FDAA has
been reorganized as a component of the Federal Emergency Management
Agency.

As the federally funded programs expanded, the Red Cross focused
primarily on mass care and emergency assistance needed until government
programs were operational, and on meeting the more extensive needs of
victims for whom government programs were unavailable because there had
been no Presidential Major Disaster Declaration or for whom they were
not adequate.

Federally funded flood relief programs are triggered by a Presidential
Declaration of a Major Disaster upon request of the governor of an
affected state. From January 1 1974, through December 31, 1979, there
have been 203 such declarations, of which 155 involved flooding or
flooding in combination with other impacts. In this six year period,
almost \$1,744,827,693 were obligated from the President\'s Disaster
Relief Fund for disaster assistance, \$697,931,000 being for individual
assistance and the remainder for public property restoration and other
projects. During this same period, Red Cross aid to flood victims
totaled \$63,415,000.

In those six years, federally funded programs provided for temporary
housing in mobile homes, for rental quarters, or for minor repairs for
over 85,000 families. Such housing can be occupied rent-free for a year,
after which the family has the option to buy or rent at a fair market
price. FEMA plans for temporary housing as a 90-day occupancy although
it often takes longer because of slow rebuilding or lack of alternate
housing in affected areas. The federal cost of such housing has been
over \$162,000,000 of which \$132,000,000 were obligated in 1977, the
year of the big Appalachian floods and the Johnstown flood.

The Disaster Relief Act of 1974 established the Individual and Family
Grant (IFG) program through which families could receive up to \$5000
for urgent needs. The program is administered through the states, with
75 percent federal funding. It has been variously implemented depending
upon the capabilities of the states involved. Some states took several
years to pass enabling legislation. In some cases more than a year
passed from the date of a disaster to the time a grant check was
written. The average grant has been well below \$5000, and is
insufficient for a significant number of families who, in many cases,
are not eligible for disaster loans. These families are referred to the
Red Cross. In the past six years, the federal share of this program has
amounted to almost \$172,000,000. States presumably have expanded or
obligated over \$57,000,000.

Another major resource, Disaster Unemployment Assistance, also provided
through state channels, represents a \$53,000,000 expenditure during the
six years, with more than 57 percent of that spent in 1977 when flooding
in Johnstown led to layoffs in the steel mills and Appalachian flooding
halted some coal mining.

An unknown amount of money also was spent to subsidize food stamps for
disaster victims and provide commodities for mass feeding of flood
victims, and to fund other programs for tax rebates, mental health
service support, debris clearance from private property, and to
administer and support the programs involved. Registration at federal
disaster assistance centers following the 155 flood related disaster
declarations totaled 519,905 persons, representing an average of about
85,000 families annually.

Also during this period, SEA and FmHA disaster loans, at varying low
interest levels, were made to 72,035 homeowners, 18,528 businesses and
12,410 farmers or rural residents to help them recover from flood
related losses. These totaled almost \$1,800,000,000, most of which
ultimately will be recovered by the Treasury.

Temporary housing, especially if it involves many mobile homes, tends to
become permanent and it may be located in a flood hazard area. In
Wilkes-Barre, the requirements of the SEA disaster loan program
literally forced those whose homes were less than 50 percent damaged to
rebuild in the floodplain. Ironically, those getting the loans were
required to buy flood insurance. Yet the flood insurance program was
designed to better manage floodplain problems.. IFG grants now include
the cost of purchasing and maintaining the first year\'s flood insurance
coverage if the family cannot afford it, but no study has revealed
whether families continue the policies after the initial year.

Some persons in the disaster response and research communities maintain
that programs for relief and rehabilitation and for flood insurance
contribute to the perpetuation and exacerbation of flood loss problems
by encouraging maintenance of the status quo, the tradition of
rebuilding a community as it was. In a sense, this may be true. Red
Cross officials once spoke wryly that they probably could mail their
forms each spring to families along certain rivers and handle the relief
process by mail. This was during the years when there were no
nonstructural flood loss reduction alternatives, and the Red Cross felt
a moral and legal obligation \'to provide needed assistance even if it
would have to be done repeatedly.

Recently promulgated regulations for implementation of Section 406 of
the Disaster Relief Act of 1974 requires state and local recipients of
disaster relief to perform a hazard mitigation assessment following
declared major disasters. To qualify for disaster loans and grants for
building and repair, homes are required to conform to standards and
elevations for both riverine and coastal situations for the 100-year
flood. Grants and loans for restoration of critical facilities such as
hospitals will have to conform to 500-year flood level requirements.

These rules noteworthy in intent, cause concern. One is that the
published processes of assessment, publications, and implementation may
be time consuming and could be lengthened further by litigation brought
by individuals, civic associations, developers, or even public officials
who object to the promulgated standards for a given area. Several
questions arise: what happens\--to people in temporary housing during
such a period? \--as the pressure of available insurance money mounts?
\-- as impatience and frustration because of delayed returns to normalcy
become a political pressure problem insofar as local and state elected
officials are concerned?

The dilemma currently is obvious in southern California, where heavy
rains in 1978 and again in 1980 have led to mudslides placing a number
of families in a seemingly insoluble circumstance that involves them,
the Red Cross, and federal programs. These are persons whose houses have
been damaged or destroyed by mudslides in Orange County. The homes are
old, and the families are believed to be ineligible for SEA loans.
Repairing the houses would require meeting current building codes
enacted after the houses were built. The estimated cost, not covered by
insurance, will be perhaps three to five times what the original homes
cost. The families can\'t afford it, the Red Cross can\'t afford it,
government programs don\'t cover it. Because the areas are now fully
developed there is no possibility of waiving the costly code
requirements. The only viable alternative is relocation outside the
county at a considerable distance from schools jobs, and friends.
Because the homes were not under flood insurance coverage, use of 1362
funds may not be possible. At this time, the Red Cross and federal
agencies are trying to devise a mechanism for helping the families, and
it will have to be decided whether or not they are to be helped to
rebuild in their hazardous locations. It is the classic dilemma of
relief versus mitigation.

For the future, the link between relief and rehabilitation and new
approaches under the National Flood Insurance program may prove
fruitful. To date, the actual move to relocate people has been small and
scattered. Rapid City cleared its floodway forever, but the same kind of
action would not be practical if the whole flood prone city of New
Orleans should be flooded by broken dikes, causing large areas of the
city to go under water as they did after Hurricane Betsy in 1965.

[Forecast Warning and Response System]{.underline}

Studies have shown that a coordinated flood forecast and response system
can lead to a substantial reduction of adverse flood impacts. The cost
of these Systems is *modest *compared with the savings in life,
property, and productivity.

The response of a river to flood producing inputs of precipitation is
slowed by the physical delays inherent in water movement from the
headwater and tributary catchments and by natural attenuation of the
flood wave. For large flowing rivers, forecasts can be provided several
days to weeks in advance, depending on the extent of the river system.
Streams in headwater catchments peak too quickly to allow the NWS River
Forecasting Centers (RFC) to respond, and Flash Flood Watches, Warnings
and Statements are released by Weather Service field offices or alerts
may be issued by local flash flood warning systems.

Approximately 200 lives are lost annually in flood related events, the
majority in flash floods. Depending upon the specifics of any particular
event, current warning systems do save lives. It is clear, though, from
National Disaster Survey Reports by NWS that improved and coordinated
forecasting and response would lead to an appreciable reduction in lives
lost. The reduction in other damages comes about through evacuation of
property and temporary floodproofing.

[Benefits of Forecast/Response]{.underline}

1\. In a study of the Susquehanna River, it was found that combining a
limited warning time of 12 to 24 hours and suitable response by the
population could result in a potential reduction of urban residential
flood damages of one-fifth to one-third. Potential benefit/cost ratios
ranged from 3.1 to 27.5 for this situation. In a Connecticut River
Study, the impact of flood warnings on four communities was studied in
detail for alternative strategies: the no-warning, limited warning (6-12
hours), maximum practical evacuation (12-24 hours), and floodproofing of
one-story houses. The results show surprisingly high benefit/cost ratios
for a forecast warning and response system. These studies, and other
figures, seem to indicate that potential annual savings of
\$400,000,000-\$500,000,000 would be possible through improved flood
forecasting and response.

[Forecast/Warning Offices]{.underline}

The various aspects of meteorology and hydrology forecasting are
severely fragmented among various groups within NOAA. The Environmental
Research Laboratories (ERL) conducts meteorological research covering
heavy precipitation forecasting. The National Environmental Satellite
Service (NESS) performs research on meteorological satellite
applications to flood forecasting and monitors satellite images to
detect hazardous weather and provide estimates of heavy precipitation
rates through their Satellite Field Service Stations, SFSS. The
operational components of NESS dealing with heavy precipitation are
co-located with selected NWS offices.

The NWS includes a National Meteorological Center (NMC) that produces
quantitative precipitation forecasts from dynamical numerical models and
statistical models. The National Heavy Precipitation Unit (NHPU) within
NMC provides guidance to NWS field offices regarding anticipated heavy
precipitation situations. NHPU can monitor current conditions and
fore-casts to insure that major discrepancies do not go unnoticed.

Atlantic and Gulf coast hurricane warnings are issued by the National
Hurricane Forecast Center (NHFC) in Miami. Storm surge predictions use
guidance from both NMC and NHFC. Similarly, the National Severe Storm
Forecast Center (NSSFC) in Kansas City is responsible for reporting on
severe convective storms including wind gusts, lightning, and tornadoes
but not flash floods.

River and flood stage forecasting is the responsibility of thirteen
regional River Forecast Centers (RFCs). Observations supporting the RFCs
are assembled in the Weather Service Forecast offices (WSFOs) or Weather
Service Offices (WSOs) that have responsibility for a designated area
handled by RFCs. In many headwater areas there is insufficient time for
the RFCs to make forecasts. Floddsin headwaters not serviced by RFCs are
flash floods and flood forecasts in such areas are called flash flood
watches. Responsibility for these headwater areas is assigned to WSFOs
or WSOs. When heavy rain is forecast, a Flash Flood Watch is issued.
When precipitation has been observed that is expected to lead to rapid
flooding Flash Flood Warnings are issued by the responsible
meteorological office which can be a WSFO or WSO Observations may be
made at Weather Service Meteorological Offices (WSMOs), such as at
weather radar stations, but these offices normally do not directly
release public Flood Watches or Warnings.

Separation of river flood stage forecasting by RFCs and headwater flood
forecasting by WSFOs is logical because of the different time scales and
methodologies used. Separation of hydrology from meteorology is not
practical in the headwaters, so service hydrologists are being assigned
to WSFOs.

The WSFO lead forecasters must be knowledgeable in hydrometeorology
because they are responsible for issuing headwater flood forecasts. Both
WSFO and WSO personnel must be prepared to issue flash flood warnings.
Hydrologists are not available 24 hours a day except during major floods
when they may not have time to deal with every threatened county.
Follow-up information within threatened areas is provided in Flash Flood
or (river) Flood Statements. Unusual reports outside areas with known
threats are sent in Storm Reports.

Summaries of forecasts and observations of hazardous weather throughout
the nation are forwarded to headquarters of agencies responsible for
disaster emergency services and disaster recovery through NWS
headquarters.

[Observations]{.underline}

Precipitation observations are divided functionally into the following
types: real-time data from gage readings and inferences from radar data;
Post-event reports; and local networks.

The real-time data include a relatively sparse network of National
Weather Service affiliated gages with reports typically every six hours
from an average of six first-order stations per state. An average
additional 10 sites per state with telemetered raingages can be
interrogated by telephone or satellite.

When heavy precipitation is occurring, volunteer observers phone in
precipitation reports normally every six hours and hopefully more often
in extreme events. The number and distribution of volunteer observers
varies greatly depending on the personal interactions of NWS and local
agency personnel with residents in flood prone basins. The NWS network
weather radars and FAA radars, from which weather information is
extracted for the western states, help to identify heavy precipitation
areas.

The National Environmental Satellite Service (NESS) monitors the
half-hourly visual and infrared imagery from the Geostationary
Operational Environmental Satellites (COES) to detect potentially
hazardous storms. These select areas are then specially examined to
estimate precipitation intensity. Coverage of this service is
nationwide.

Post-event reports include gages not read or not reported until after
the event and such information is available from a large number of
sites. Typically, hourly data are available for 60 sites per state and
daily totals are available for 240 sites per state. These data are
collected for climatic studies and used extensively in planning and
research.

Stream and river stage and discharge information is collected by many
organizations, mostly for water management. Waterways on which flow is
controlled by a series of dams have much more thorough data collected
each day, or every six hours during critical periods. Uncontrolled
rivers generally have sparse coverage, particularly regarding discharge.
Headwater basins subject to flash flooding have few stage observations,
relative to the needs of hydrologic models. Snow cover observations
using satellite imagery has been finding wider use in western states.
These observations are most useful for predicting runoff values from
snow melt for water management.

[Communications]{.underline}

In spite of the diverse means that can be exercised before and during
floods, communication remains one of the weakest links in the
forecast/warning system. Land lines carry the bulk of observation and
warning messages, and these often fail when heavy rains begin and before
critical information is collectd and disseminated. The voice circuits
often remain operable after the teletype and telephone lines fail, but
they become overloaded with traffic that appears more important than
observations of rainfall and stream gages.

Observation-collection and forecast/warning dissemination usually
depeneds on leased telephone and telegrpahic lines. Some dial-up lines
are used to interrogate remote rain and stream gages, called telemetered
gages. Radio reporting and satellite reporting gages are employed in a
few special programs. Intrastate low speed telegraph lines, including
NOAA Weather Wire and State Emergency Service lines are primary means of
sending warnings to action agencies and commercial broadcasting
stations.

NOAA weather radio is the most direct means for communicating official
flash flood warnings to the public. The Emergency Broadcast System (EBS)
can be used by commercial broadcasters to forward warnings received by
NOAA-Weather Wire to the public. The Natiional Warning System (NAWAS) is
a voice cicruit connecting NWS offices with many police and civil
defense offices. Different states have unique voice communication
circuits, usually for police business.

[Preparedness and Response]{.underline}

Improved forecasting and warning is of little value unless local
communities are prepared to respond. Construction in the floodplain
insures that flood hazards exist and disaster preparedness is needed,
including floodproofing, evacuation plans, relief plans, and a
forecast/response system keyed to those plans.

Agencies such as the Corps of Engineers, Soil Conservation Service,
Water and Power Resources Service, and Tennessee Valley Authority are
active in flood hazard mitigation through planning, construction, and
operation of water management projects The Federal Emergency Management
Agency helps coordinate preparedness efforts among local, state, and
federal agencies through the Office of Disaster Response and Recovery.

Response to flood forecasts (or Flash Flood Watches) is normally the
duty of state and local civil defense/emergency service organizations.
Clearly, response is essential to achieve flood hazard mitigation and
this response must be to a forecast/warning that, in turn, is a response
to an observation. NWS staff cannot maintain the county level
observation network nor can they establish or maintain a county response
system or an industrial response system. The NWS does provide technical
assistance to communities in establishing a Local Flash Flood Warning
System (LFFWS) which includes the local maintenance of rain and stream
gages, and development of response plans.

Private industries exposed to severe flood hazards often develop their
own flood forecast/warning and response systems. These systems are
developed for maximum benefit/cost ratios and often are excellent
examples of detailed planning with specific responses keyed to specific
warnings.

State offices of emergency services cooperate with national and county
programs. Federal funding and technical assistance often are channeled
through regional commissions controlled by states. It is impossible for
NWS to deal separately with each county without assistance from state
personnel during phases of planning, evaluation, and maintenance.

The role of planning organizations like river basin commissions and
economic development associations is often critical to success. Although
many differences occur in specific cases, their role is that of
coordinating intergovernmental cooperation. They can sponsor meetings,
conduct surveys, and compile information from many sources. Normally
they do not have operational responsibilities but they can foster
development of an operational system and monitor the extent to which it
meets users\' needs.

The above discussion identifies many groups active in planning responses
to flood forecasts. Decisions to be coordinated prior to occurrence of
damage include forecasting, water storage, warning, evacuation and
relief planning. It is when time is of the essence and communications
are overloaded and subject to failure at any moment that federal, state,
local, and individual actions must be coordinated to prevent major
damage.

[Performance of the Existing System]{.underline}

Natural Disaster Survey Reports have been prepared by NOAA for major
disasters and by NWS for other disasters. They focus on the
forecast/warning system including dissemination and local response. The
cases summarized below will be used to highlight the findings of these
surveys. These reports are rather frank and contain enough detail for
the careful reader to discern major strengths and weaknesses in the
system. Outside professionals participate in some of these surveys.

In the 1970s three major flood disasters occurred in Pennsylvania and
several in West Virginia and Kentucky. Too few staff and vulnerable
communications were highlighted in NOAA\'s Tropical Storm Agnes Disaster
Survey report. As a result, 15 additional hydrologist positions
were\~authorized by Congress. Yet, this staff still did not exist in
1977. This example is part of a larger problem: 880 new positions have
been authorized in the National Weather Service during a period in which
staff diminished from 5022 to 5016, from 1967 to 1979. While new
positions and new programs are authorized, existing positions are being
abolished with few reductions in programs. The result is a large growth
in programs with zero growth in staff.

A comprehensive interagency report reviewed the flood forecast and
warning system in the Susquebanna River Basin six years after the
multibillion dollar disaster associated with Tropical Storm
Agnes.^5\ ^The report revealed that progress was being made, but it was
slow and erratic. Recommendations were made for substantial improvements
in the speed and reliability of the river forecasting system, an
improved flash flood warning system, and improved local response. This
report emphasized the need for annual or semiannual reviews of the
systems to insure that progress is made and that none of the
intergovernmental links deteriorates.

· The Johnstown, Pennsylvania, disaster in 1977 was reviewed in detail
by a NOAA Survey team. This report concluded that the flash flood
warning system did little good in this storm that killed at least 76
persons and caused \$200,000,000 damage. The National Weather Service
had not released a Flash Flood Watch and did not detect the flooding
rains until well after communications had been broken between the
stricken area and the outside world. The city was officially closed to
incoming traffic at midnight, but the NWS flash flood warning was not
issued until the following 2:40 a.m.

· In 1979 flash floods in eastern Kentucky caused three deaths and
\$13,000,000 damage and damaged or destroyed 450 homes. The flood
producing rains went undetected and no NWS Flash Flood Watch or Warning
was released. No realtime rainfall observations were available to radar
operators and offices with flash flood watch/warning responsibilities.
The flash flood rainfall reporting network did not respond, and early
reports of the flooding situation were not passed along to the NWS until
after the event. A serious breakdown in data collection appeared to have
occurred The avail-able radar and satellite information was of limited
usefulness to the fore-casters This report shows the tremendous
devastation that can occur from a storm 30 miles across that was
undetected by the existing observing system in 1979.

· National Weather Service and the Commonwealth of Pennsylvania Civil
Defense organized local flash flood forecast and warning systems
throughout the state (except in Philadelphia) beginning in July 1978.
Between January 1, 1979, and September 1979 ten flash flood events
occurred in 16 counties. The systems performed excellently in three
counties, well in ten, and poorly in two. Performance was measured by
the extent to which information was exchanged between NWS and local
coordinators and the extent to which warnings were disseminated.

· Tropical Storm Amelia moved inland over south Texas in August 1978,
producing precipitation depths in the hill Country \-- Kerr, Gillespie
and Bandera counties \-- and in Shackelford County, 200 miles away, of
20 to 30 inches in over 12 hours. Twenty-seven persons died in the hill
Country where the flash flood occurred during the early morning. Six
persons died in Shackelford County.

The post-disaster survey found that the lack of real-time river and
precipitation reports seriously affected ability to make timely and
accurate forecasts. This absence of data during the storm was due to
lack of automatic, telemetered raingages and breakdowns in landline
communication. Radar data were helpful, but without precipitation data
NWS could not fully utilize the radar information.

· Two storms on September 12, 1977, inundated the Kansas City
Metropolitan Area with 16 inches of rain resulting in a flash flood
killing 25 persons and causing damages estimated at \$90,000,000. It was
found that tke weather radar was extremely helpful in providing
information used in the flood warnings. Satellite data also were useful
in identifying areas of thunderstorm development and in observing
thunderstorm movement. Data from hydrological networks were of little
use because they arrived too late to assist in making the forecasts, or
too few reports were received. Again, this points to the need for
automatic, telemetered gages from which real-time data can be acquired.

Persons who work with the nation\'s flood forecast and warning system
know its weaknesses and what needs to be done to overcome them.
Improvements are being implemented slowly because of staffing
limitations. Field personnel, through continued determination, oft en
make the system work in spite of obvious difficulties.

Clearly, substantial improvements are needed in making, collecting, and
processing observations. Forecast and warning dissemination during flood
producing storms is a substantial problem that must be overcome.
Designing the National Weather Service activities and the Local Flash
Flood Warning Systems to be mutually supportive will become increasingly
important as the goal extends beyond lifesaving to damage reduction in a
hazard mitigation system. The forecast and warning system of the 1970s
will not meet the requirements of the 1980s.

[Agency and Individual Perceptions of the Existing Systems]{.underline}

Misunderstanding concerning forecast and warning responsibility is
widespread at all levels. The problem is that water management and flood
hazard mitigation is the business of many agencies and people confuse
many of those activities with the public forecast and warning activity.
If precipitation information and flood mitigation information in a
locality is handled 364 days per year by one group, it is difficult for
another group to be recognized on the one day that a flood strikes. For
example, a dam operator in the Johnstown, PA, area reported
precipitation to the organization that operated the Flood Control
Project in his basin. At 8:00 p.m. when intense precipitatiQn began he
called that office, which was closed. His call to the after-duty hours
number failed because the line was out. He also had the NWS number but
could not even try that one since by then his phone was dead. The flash
flood struck and close to 80 persons were killed in a five county area
of Pennsylvania without the National Weather Service 5 receiving a
single authoritative report on a very intense storm (4ohnstown, PA, July
1977)

It is not clearly perceived whether hydrologists or meteorologists
should do flash flood forecasting. Policy changes evolve differently
from individual actions when capabilities are not provided along with
responsibilities. For example, one office may have the responsibility
for providing flash flood warnings to a particular county. The flash
flood watch for that county, however, is the responsibility of another
office. Flash flood guidance is supplied by a third office, and
collection of the precipitation data necessary for all these functions
is the responsibility of another unit. Early evidence of a problem may
be detected by a radar operator at another site. Alternately, the storm
may be spotted first by a satellite specialist. In different locations
and at different times of day almost any combination of the above must
be coordinated.

Perception problems, along with many other problems, can disable a
system during an unusual crisis. Exercises, drills, or tests are
essential parts of any emergency system. If flood hazard mitigation is
to succeed, the forecast, warning, response system not only must be
prepared but also must be tested. Each locality must participate in a
test, either real or simulated, at least twice per year.

[Research Needed for Improved Forecast/Warning Systems]{.underline}

Precipitation forecasting is among the most difficult meteorological
problems. The precipitation and hydrologic data assembled by a
computerized flood information system can be used to develop and test
advanced meteorological and hydrologic techniques and models. These
advances then can be implemented using the same computerized data base.

Meteorological research is needed in small-scale regional (mesoscale)
numerical prediction models. Operational implementation of these
techniques requires very large computers and the data bases assembled in
the minicomputers, but the large computers could be obtained when
justified by research results. In addition to numerical analysis and
prediction model development research, intensive case studies of
convective storms are required to understand the key mechanisms that
determine which storms will produce heavy precipitation and which will
move fast enough that local accumulations will be tolerable.

Research is required to systematically measure performance and
validation of hydrological forecast models. Operational models in use in
the United States range from very simple runoff curves to a rather
sophisticated conceptual soil moisture accounting (SMA) hydrological
model. Operational implementation of the more sophisticated SMA model
has been hampered by lack of skilled hydrologists to calibrate the model
for particular basins even though the Office of Hydrology in the NWS
conducts training programs in model calibration. Research is needed to
develop improved methods for calibrating various hydrological models and
for comparing the performance of the various models now being
implemented throughout the U.S. Studies comparing model performance and
calibration/implementation effort are desperately needed.

A vital need is to develop reliable and scientifically sound forecasting
models that can be implemented and calibrated easily and efficiently on
mini-computers to be used in county level flash flood systems;
otherwise, these systems never will be set up due to the above problems.
The large conceptual models currently used in the United States require
large computer systems which cannot utilize efficiently real-time data.
Such models are more appropriate for water management than for flash
flood forecasting.

At present the NWS is modifying its flood forecasting system to
incorporate various hydrological approaches within a compartmentalized
system. Additional support should be made available to the NWS to
incorporate recently available models within this system.

The main operational problems in improving the flood forecasting system
lie in data handling and forecast uncertainty. Improved methods are
needed for real-time data analysis and for handling and converting the
hydrological data into model inputs especially for the analysis of
precipitation data. These methods are critically needed for models being
used for rapidly responding headwater areas. In the area of forecast
uncertainty, methods must be developed and implemented to quantify
forecast uncertainty caused by uncertainty in data inputs (areal
precipitation estimates, streamflow measurements, evapotranspiration
estimates) and hydrological model limitations.

Current forecast model procedures are incapable of utilizing real-time
data to update internal model variables that define current hydrological
conditions. Procedures must be implemented so that current model results
correctly filter the data to accurately reflect current observations.
Such procedures do not require unusually powerful computers and these
systems are being installed in other countries. Computer systems with
which hydro-meteorologists can interact to examine data, analyses, and
predictions to insure high quality output are readily available.

At present, the National Weather Service is aware of many of the above
research needs, and at tempts are being made to initiate research. It is
questionable whether the NWS supervisors can successfully manage this
research activity or carry it out with its current personnel level.

Satellite technology applications require research and development in
three areas: detection of conditions that assist in prediction of storms
with heavy precipitation, estimation of heavy precipitation in progress,
and communications of rain and stream gage reports and watch and warning
information.

Satellites have unique capabilities to observe wind, water vapor, cloud
pattern, temperature, and soil moisture conditions needed to predict the
probability that flood producing storms will develop. Thus, 2- to
12-hour heavy precipitation probability predictions could improve
markedly from successful application of satellite systems. Radar is
useful only after the storms form, rain gages after the rain begins to
accumulate, and stream gages after the streams begin to rise.

Estimation of heavy precipitation rates within the United States by
satellite is unlikely to meet the reliability requirements of a
comprehensive flood hazard mitigation program. The digital
radar/automatic raingage systems must be implemented to serve these
needs. At any rate, satellite rainfall estimates will provide required
back-up as the radar system will fail occasionally when information is
essential. Also, the satellite information extraction system required
for rainfall estimation will contribute greatly to the prestorm
observation function described above.

Satellite communication systems can be used to collect reports from rain
and stream gages and relay them to any location. The requirement for
reliable communications among all locations during the flood also can be
met by satellite systems. Currently, costs favor ground-based microwave
and radio links, but these are still expensive; substantial saving may
become possible using satellite links in the future.

References

for \"Forecast Warning and Response System\"

1 Day, H.J. March 1970. Flood warning benefit evaluation \-- Susquehanna

River Basin (urban residences). ESSA Technical Memorandum WBTM

Hydro 10. Silver Spring, MD: National Weather Service, Office of

Hydrology.

2 Day, J.J., and K.K. Lee. February 1970. Flood damage reduction
potential of river forecast services in the Connecticut River Basin.
NOAA TM, NWS Hydro 28. Silver Spring, MD: National Weather Service,
Office of Hydrology.

3 Bresehan, T.P., ed. April 16-17, 1979. Industrial flood preparedness
proceedings of the flood warning and flood proofing seminar for
industry) Williamsport, PA. Harrisburg, PA: Pennsylvania Department of
Community Affairs, Bureau of Planning.

4 Mogil, H.M., J.C. Monro, and H.S. Croper. 1978. NWS\'s flash flood
warning and disaster preparedness programs. American Meteorological
Society Bulletin 59, 690-699.

5 Flood forecast and warning system evaluation. January 1979.
Harrisburg,

PA: Susquehanna River Basin Commission. 139 pp.

6 Johnstown Pennsylvania flash flood of July 19-20, 1977. Natural
Disaster Survey Report 77-1. Rockville, MD: NOAA. 60 pp.

7 Pike, KY \-- Buchanana, VA flash floods of July 15, 1979. Natural
Disaster Survey Report. Silver Spring, MD: National Weather Service. 22
pp.

[Reducing The Risk Through]{.underline}

[Land-Use Management]{.underline}

Flood damages could be greatly reduced if human activities on
flood-plains could be made more compatible with natural processes and
systems. Floodplain developments and uses designed in anticipation of
inevitable flood events could prevent much suffering and economic loss.
Activities in one portion of a watershed often affect flood
characteristics in another. For this reason floodplain management
programs must consider the existing and potential watershed developments
if they are to be successful. For example, sites downstream of
urbanizing areas, major drainage projects, and timbered forests could
experience a change in flood regimen. Management plans within a
watershed must take into account existing floodplain uses and damage
potential.

Undeveloped floodplains suffer little economic damage from floods, and
wise government policy will do nothing to encourage damageable
properties to be located on them. These areas include swamps, marshes,
floodplain forests, backwaters, many barrier islands, and large coastal
areas. Another level of floodplain-use is that of commercial timber or
crop production which is economically viable under local flood
conditions. Urbanizing floodplains are undergoing the transition from
low risk to potential disaster areas.

Governments can exercise certain control over floodplain development
without resorting to ordinances. The direction of development can be
encouraged away from floodplains by the wise location of schools,
courthouses, and government offices. Development also can be retarded by
providing minimal sewer and highway facilities to floodplains. In some
cases public exposure to floods could be eliminated if the government
would not provide access to barrier islands. Inexpensive measures such
as posting flood heights and publishing flood maps help. Long-term
policies which removed damageable buildings from floodplains after they
had served their economic lives would greatly reduce damages.

[Encroachment Lines]{.underline}

Once a floodplain is adequately mapped, local authorities can take steps
to protect structures and public safety by restricting development which
threatens to reduce the capacity of the local floodway. Such
restrictions usually are designed to assure that a given flood flow will
pass through an area without causing excessive damage. The restricted
area is bounded by encroachment lines on either side of a stream or body
of water inside which no structure or fill may be added without a
special permit. If encroachment lines are not established, the filling
of low spots and the construction of new buildings will reduce the flood
carrying capacity and cause increased damage to existing property. In
undeveloped areas encroachment lines should be made to warn developers
of flood threats and prevent large investment in unprotected property.

[Urban Storm Drainage]{.underline}

Urban storm drainage has been developed through municipal engineering,
with programs adopted holding a balance between budgetary limits and the
complaints of citizens flooded. Despite considerable efforts,
particularly by the American Society of Civil Engineers, little
federally funded research or general data gathering relative to urban
drainage has been done. Large cities generally have been able to
assemble adequate staffs of competent hydraulic engineers, but most
storm drainage systems of smaller cities and towns have been planned
inadequately. For example, culverts and storm drains usually have been
sized with no allowance for future increases in storm flows due to
future, more intensive development.

In many cases, storm and sanitary wastes are carried together in
combined sewers. This situation makes it almost impossible to avoid
massive pollution of waterways in time of storm. Where sanitary sewers
are separate, they usually overflow into the streams or into storm
sewers during wet weather; in either case, urban streams are almost
invariably polluted from raw sewage and high bacterial content of runoff
from streets.

In most cities, storm sewers are sized for a storm of estimated
frequency to be exceeded perhaps once in 10-25 years. When larger storms
occur, the storm water overflows the storm sewer system and flows
overland, down streets, lawns, and vacant land.

In recent years developers in many areas have been required to provide a
given degree of storm water detention or infiltration, intended to
compensate for increases in flood hazards which otherwise would occur.
This protection is usually provided by detention basins, although
recharge basins, dry wells, roof-top storage, or other alternatives may
be allowed. Commonly consideration must be given to protecting against a
range of floods up to the magnitude of that expected to be equaled or
exceeded once in 100 years.

The requirement for alleviation of potential flood hazard almost always
is calculated at the site, with no consideration of effects further
downstream. From the state and federal viewpoint, this difference is
important. The favorable local effect of a few hours of detention of
peak flows diminishes rapidly downstream where total volume from urban
runoff accumulates, increasing peak flows of the larger rivers.

It now appears that settlement in detention basins will be very
effective for water quality improvement by removing bacterial pollution,
and lead and hydrocarbons from urban runoff; it will be less effective
in removing organic pollution, phosphates, and copper. Very soluble
pollutants, such as nitrates and ammonia, are not materially reduced by
settlement.

In planning for dual purpose use of detention basins to remove
particulates, an economic balance must be struck between flood control
and water quality. The assumption is that the regulation is designed for
areas in which the use of detention basins for control of floods is
justified and acceptable in itself, and that the control of particulates
is to be justified on an incremental basis, as a project function which
would not be included except as an adjunct to another project purpose.

[Zoning and Building Codes]{.underline}

The establishment of a special form of zoning in the floodplain is the
basic mechanism by which further development is precluded or limited.
Usually a floodway is established within which no buildings are allowed
to be built or fill material placed; and permitted facilities, such as
bridges and fences, are strictly defined. Outside the floodway a flood
fringe area is defined, within which any buildings built must safely
withstand a specified design flood, such as the 100-year flood. In
practice, this generally means constructing a fill upon which to build
above the specified elevation in inland areas and on piers and pilings
in coastal areas.

Other provisions can be required) which in effect are modifications of
general codes. For example, it is common to prohibit basements in such
areas, because of the likelihood of their settling and leaking if built
in filled ground.

Special building restrictions, such as construction above a projected
elevation of the water surface, are frequently imposed in high hazard
coastal areas.

[Sanitary And Well Codes]{.underline}

During floods, water supply and wastewater collection systems may be
inundated and sewage may back up into homes and contaminate water wells.
Overloaded, poorly designed, improperly constructed and maintained
storm, sanitary, and combined sewer systems can result in flood damage
in basements even when water does not stand in streets. It is important
that wells and water distribution systems be designed to minimize risk
of contamination. Comprehensive ordinances specifying the design and
location of such facilities are necessary to protect public health.

[Relocation]{.underline}

Past policies and public attitudes often encouraged flood victims to
rebuild on the floodplain. Such defiance of natural forces has lead to
repeated tragedies in some communities. Programs which relocate victims
outside floodplains would be far more sensible and ultimately save
money. The vacated land could be used for a variety of functions
including recreation, parking, wildlife habitat, and floodway.

[Public Acquisition]{.underline}

Although the nation has purchased millions of acres for flood control
dams, it has been slow to accept buying floodplain lands to prevent
flood damages. The public interest in preserving the capacity of
existing flood-ways is great because their loss will increase flood
heights and velocities. In general, floodways should be preserved by
regulation. Where development already exists in floodways, selected
floodplain areas may be obtained by outright purchase or by purchasing
selected development rights. For example, in agricultural areas flood
carrying capacity can be maintained by buying development rights and
leaving the farming operation intact. In certain urban situations it may
be desirable to purchase the land outright. The purchase of land for use
as a floodway could easily be made compatible with a variety of other
uses including wildlife protection, river recreation, hunting, timber
production, and the growing of biomass for energy development. It must
be recognized though that the presently occupied floodways are so
extensive that only in especially urgent situations can purchase be
financed.

[State and Local Land-Use Controls]{.underline}

During the 1970s many state and local land-use control programs have
been designed to avert or mitigate flood damage. Whether these programs
employ regulation, tax incentives, and/or compensation to reduce flood
damage depends largely on the character of the land and its present use.
The land may be a natural flood storage area, such as a floodplain or
wetland, or it may be a source of stormwater runoff. In short, either
floodplain management or stormwater management may be involved. The land
may be developed or undeveloped.

Information below describes the types of state enabling legislation
authorizing control of land-use for flood hazard mitigation, summarizes
the constitutional principles governing runoff and flood storage
regulation, and cities judicial decisions applying these principles to
specific cases.

[State Enabling Legislation]{.underline}

Three types of state enabling legislation exist: general and permissive,
specific and permissive, and specific and mandatory. General, permissive
legislation authorizes the state and/or its local governments to act to
promote public health, safety, welfare, and morals. Specific, permissive
legislation authorizes the state and/or its local governments to act to
protect people from the dangers of flooding. For example, Massachusetts
authorizes zoning of land \"\...subject to seasonal or periodic
flooding\...\" so that it not be used \"\...to endanger the health or
safety of the occupants. Specific, mandatory legislation requires
action. For example, New Jersey requires local governments to enact
floodplain zoning once the state has delineated the floodplain. Flood
hazard mitigation regulations adopted under each form of enabling
legislation have been upheld.

States may authorize state or local purchase of wetlands or land subject
to flooding. The authorization may provide for purchase of voluntary
agreement or condemnation of the fee or lesser interests. Wisconsin, for
instance, voted funds for state purchase, by eminent domain if
necessary, of wetlands easements.

A variety of state laws provide tax relief as reduced assessments on
land-use in open space, including use as floodplain and wetlands. These
tax laws offer incentives to land owners but do not assure floodplain or
wetland preservation.

Some states, including New Jersey, have many local ordinances requiring
developers of property not in the floodplain to build detention basins
as a condition of municipal or county approval for development of the
site. Most of these ordinances require only that the peak runoff from a
design storm occurring after development not be greater than would have
been produced by the same storm prior to development. Such ordinances
are now extensively utilized) and no information is available as to
their being contested in court. Other ordinances go further and require
that the post-development peak discharge for a given design storm be
less than the pre-development discharge) presumably to compensate for
the fact that for other still larger storms the post-development
discharge would not be similarly controlled.

In still other cases, a further requirement is added that runoff from at
least the smaller storms be retained long enough for particulate
pollution to be settled out prior to discharge. These more stringent
applications of stormwater management control are relatively recent in
origin and have been applied only in a few jurisdictions; so lack of a
judicial record leaves their legal status still unconfirmed.

[Constitutional Principles]{.underline}

When a public agency takes or condemns land) some constitutional issues
arise: whether the purpose is a public one) whether there is a present
need for the taking, and whether the compensation is just.

When a public agency regulates land, a land owner may raise several
constitutional issues: the regulation violates the requirements of due
process of law) the land has been taken for public use without just
compensation) and/or the regulation denies the land owner the equal
protection of the laws. In essence) the issue to be addressed is whether
the regulation is reasonable and fair. The United States Supreme Court,
upholding the validity of New York City\'s historic district zoning as
it applied to Grand Central Terminal, acknowledged in a 1978 opinion
that there is no fixed test by which to distinguish valid from invalid
regulation:

\..... this Court) quite simply, has been unable

to develop any \'set formula\' for determining

when \'justice and fairness\' require that economic injuries caused by
public action be compensated by the government, rather than remain
disproportionately concentrated on a few persons\....\"^5^

Floodplain regulations that help the public by lessening flood damage
also tend to decrease the value of the regulated land. The market value
of real property to some extent reflects the discounted value of
prospective development, and if that prospect is eliminated the holder
of, or investor in, undeveloped property may suffer a loss just as real
as that suffered by the holder of tangible improvements destroyed by
flood. The land owner may challenge the regulations) alleging that his
property has been \"taken\" in the sense that the restrictions deprive
him of a substantial portion of the property\'s value.

Among factors considered by courts are the extent of the loss of market
value, the value of the public interests furthered by the regulation,
the number and kinds of uses left to the owner, the possible economic
return left to the owner, and the net value of the public benefit over
private costs. Some courts have said that prohibiting a use to prevent
harm to the public is constitutional while requiring a user to provide
public benefits is not. This distinction is not particularly helpful
because in every case the public receives a benefit when it is protected
from the harm that would accrue from the use, although the owner may be
harmed by being barred from the use. Many decisions, including the Grant
Central Terminal case, hold that regulation enacted for a valid public
purpose will be upheld unless the land owner is denied all reasonable
beneficial use of the land.

The requirement that all persons must receive equal protection of the
laws means that the laws must not be discriminatory. In the context of
flood hazard regulation, this means that similarly situated property
owners should be similarly treated.

The problem of equal protection arises most forcefully in the
flood-plain context regarding establishment of hazard area boundaries.
Specifically, problems are inevitable concerning the
[inclusion]{.underline} of property believed by its owner not to be
flood prone and the [exclusion]{.underline} of property which may be
flood prone. This in turn raises questions as to the technical
sufficiency of floodplain maps and studies for purposes of land-use
regulations. This entire matter is under study by the Federal Emergency
Management Agency with the assistance of a special Committee on Flood
Insurance Studies established within the National Academy of
Sciences/National Research Council. The report of that committee is not
yet available.

[Judicial Decisions]{.underline}

Most decisions pertain to regulation of undeveloped floodplains and
wetlands, but as awareness of the costs of flooding mounts) efforts are
increasing to affect use of developed land and to control stormwater
runoff. Principles articulated in decisions regulating the floodplain
and wetlands will contribute to emerging jurisprudence applicable to
other situations involving developed and undeveloped land.

[Developed Land]{.underline} - Conventional development increases
flooding. The degree of increase in flood risk depends on the location,
density, and bulk of the development. Where the impact is great) the
public may act to remove structures through purchase, amortization, or
nuisance abatement. In most instances purchase is the only option. In
fixing the compensation, the value of flood prone property may be
discounted by the probability of future flood damages. There are some
exceptions to the need to buy and pay compensation.

Zoning districts) including mapped floodplains, have nonconforming uses
and structures. Whether these uses or structures can be discontinued by
amortization will depend upon the reasonableness of the amortization
provisions relative to the public benefit provided and the economic
burden placed on the property owner.

If a building, excavation, or dike is a nuisance, creating a hazard to
the lives and property of others, it may be abated.

If the government can assert a superior title to the land it may remove
buildings without paying compensation. For example) buildings and other
encroachments on some beaches and wetlands, or below high or low water
marks on navigable rivers, may be on public land or be subject to the
navigation servitude, the public trust, or an implied dedication to
public uses.

Even compensated takings can seem inequitable and be unpopular, and
their impact can be lessened. Acquisition of floodplain properties may
be more acceptable if part of a broad, popular program of urban renewal
such as open space development. Sometimes less than the fee may be
taken. Buildings can be purchased and moved away and resold, leaving the
land to the private owner, or the land can be taken but the buildings
retained and moved by the owner, sometimes to a lot furnished by the
public.

After flood damage has occurred, prohibitions against rebuilding or
repairing damaged structures may enable the public to acquire property
at a reduced price. Sometimes this can be combined with a program in
which the public purchases flood free lots on high ground and sells or
trades then to dispossessed property owners. Relocation assistance to
occupiers) whether tenants or owners, is a form of personal
compensation.

New uses and new structures can be required to conform to the zoning
ordinance and building codes. Building codes can require design and
construction features that minimize the risk of flood damage even though
there is an added cost to the owner, if requirements of the code relate
to the magnitude of the risk and can be shown to be both physically and
cost effective.

[Undeveloped Land]{.underline} - Objectives of a range of regulations
used to minimize flood damage may include these: preservation of natural
functions of floodplains and wetlands) protection of structures allowed
to be built in flood prone areas by specifying design characteristics,
and detention of stormwater runoff. Riverine floodplain zoning by local
government now is widespread, stimulated by the National Flood Insurance
Program. Coastal flood hazard zoning and marshland zoning are less
common but increasing. Regulation of development to reduce and/or slow
stormwater runoff also is increasing.

Justification for retention of floodplains and marshes in their natural
state is that these lands, by acting as flood storage areas, reduce the
severity of flooding. Justification for requiring developers to create
stormwater detention systems is that the impervious cover which is a
concomitant of development increases the amount and rate of runoff. It
is beyond dispute that both forms of regulation serve to promote public
health, safety, and welfare. Whether specific regulations may be so
burdensome on land owners as to be found invalid remains a subject of
some litigation.

Allison Dunham, in 1959, described several arguments supporting
regulation of floodplains: development in the floodplain obstructs flood
flows and results in greater damage to others, persons occupying
structures in the floodplain are likely to suffer personal and property
damage) and flood damage leads to public costs for flood relief. Courts
frequently have cited Dunham with approval in upholding floodplain
regulations.

Judicial support for regulation of development in floodplains dates back
to 1924, but because little floodplain zoning was adopted until the
1960s, most decisions are more recent. Cases from Massachusetts) New
Jersey, and Pennsylvania, upholding the constitutionality of riverine
floodplain regulations, typify judicial responses. The Massachusetts
Supreme Court) upholding the 1963 Dedham ordinance, stated that there
was no taking because the plaintiff retained a beneficial use of the
land, despite an alleged drop in value of 88 percent. A 1979
Massachusetts decision, upholding the denial of a special permit to
build a warehouse and office building in a floodplain, illustrated the
courts? deference to administrative findings. The Court stated that the
finding of the Board of Appeal \"\...of the seriousness of the problem..
is controlling\...\" unless the finding is arbitrary or legally unsound.
New Jersey also deferring to administrative agency findings sustained
denial of a variance from a three-year moratorium was reasonable
because* *\... increased urbanization and changing circumstances warrant
a more sophisticated approach to flooding problems. A 1979 Pennsylvania
decision goes farther than most in effect denying a land owner\'s tight
to a reasonably beneficial use. Once again, a court was upholding
administrative action. The Court said that the owner \"\...finds himself
for all practical purposes stuck with a useless property. But in the
interest of all the residents, he must suffer along with other property
owners who are likewise affected by the ordinance\....\"^12^

Decisions concerning coastal flood hazard zoning are less common, but
there is no reason to anticipate a different judicial response than for
riverine floodplain zoning. The New Jersey Supreme Court has upheld a
total ban on residential construction in an area seaward of a building
line established based on past storm experience.^13^

The public purposes stated as being served by wetland regulation do not
always include flood storage; 50 some of the decisions concerning the
validity of such regulations are not directly in point. A New Jersey
Supreme Court decision) holding invalid a wetland zoning ordinance which
essentially barred all development in 1500 acres of marsh, took care to
distinguish this situation from floodplain zoning. A New York court
reached a similar conclusion, holding the state Fresh Water Wetlands Act
invalid as a violation of due process, because \..... the property (is)
unsuitable for any reasonable income-productive or other private use for
which it is adapted and thus destroys its economic value, or all but a
bare residue\....\" On the other hand, the Connecticut Supreme Court
sustained denial of a state coastal wetlands permit under a statute
whose purpose includes \"\...protection of life and property from flood,
hurricane and other natural disasters\.... One famous wetland zoning
case, in which the court adopted a very distinctive line of reasoning,
is [Just]{.underline} v. [Marinette County]{.underline}. Wisconsin
requires its counties to zone shoreland to protect water quality; if a
county fails to zone, the state may do so. The ordinance in question was
upheld on the grounds that a land owner has \"\...no absolute and
unlimited right to change the essential natural character of his
land\...\" and that the state has an \"\...active public trust
duty\...\" to protect the quality of its navigable waters, a duty which
extends to zoning of shore-lands. The Wisconsin Court, unlike other
courts passing on wetland ordinances, defined reasonable beneficial use
of land in an environmental rather than an economic sense.

To resist constitutional challenge, stormwater management and flood
plain and wetland regulations should be written to emphasize that they
advance the police power objectives of protection of public health,
safety and welfare: through prevention of uses that increase danger to
other property, protection of people who do not have a free or knowing
choice to be in the flood prone area, and prevention of sales of
endangered property to the unsophisticated or unwary. Regulations also
should emphasize their conformity with state and regional flood hazard
mitigation goals and *their role in furthering environmental values.
This approach will go far to *resist a charge of lack of due process, by
showing that the regulations are reasonably related to stated public
purposes and are not arbitrary, capricious, unreasonable, or
confiscatory.

References for

\"State and Local Land-Use Controls\"

1 M.G.L.A. ch. 40A, 2.

2 N.J.S.A. 58:16A-50.

3 W.S.A. 32.02; W.S.A. 990.02 (35).

4 Keene, John C., and Ann L. Strong, et al. 1976. Untaxing

Open Space. Washington, DC: U.S.G.P.O.

5 Pennsylvania Transportation Company v. New York City, 438 U.S. 104 at
124, 1978.

6 Modjeska Sign Studio v. Berle, 373 NE 2d 255 (CANY), 1977.

7 Flood Control Via The Police Power, 107 U. Pa. L. Rev. 1098, 1959.

8 City of Welch v. Mitchell, 121 SE 165 (W.Va.), 1924.

9 Turnpike Realty Co. v. Town of Dedham, 284 NE 2d 891 (Sup. Ct. Mass.),

1972\.

10 Subaru of New England, Inc. v. Board of Appeals, 345 NE 2d 880
(Appeals Ct., Mass.), 1979.

11 Cappture Realty Corp. v. Board of Adjustment of Borough of Elmwook
Park,

336 A2d 30 (N.J. Super.), 1973.

12 Kraiser v. Zoning Hearing Board of Horsham Township, 406 A2d 577 (Pa.
Cmwlth.), 1979.

13 Spiegle v. Borough of Beach Haven, 218 A 2d 129 (N.J. Sup. Ct.),
1966.

14 Morris County Land Improvement Co. v. Township of Parsippany-Troy
Hills,

193 A2d 232 (N.J. Sup. Ct.), *1963.*

15 Spears v. Eerie, 407 NYS 2d 590 (Sup. Ct., App. Div.), 1978.

16 Brecciaroli v. Connecticut Commissioner of Environmental Protection,

362 A2d 948, 952 (Conn. Sup. Ct.), 1974.

*17 201 *\~ 2d *761 (wi\'s. Sup. Ct.), 1972; see also: Sibson V. State,
\~1\~A*

2d 239 (N.1\~. Sup. Ct.), 1975.

V INSTITUTIONS AND THEIR FUNCTIONS

Introduction

Public and private institutions for coping with natural flooding existed
on this continent beginning with levee districts established to protect
agricultural lands in the Lower Mississippi basin before the Louisiana
Purchase of 1803. Location of our major cities close to waterways, at
the time when commercial navigation was almost the sole means of
commercial transport, made urban flooding in many places inevitable.

Institutional responses, initially, to modify the flood hazard by
construction of levees appeared to be the only rational course of
action. The federal government assumed responsibility in 1927 for flood
control on the Mississippi River from Cairo, Illinois, to the Gulf of
Mexico through the Mississippi River and Tributaries Project of the Army
Corps of Engineers.

Contemplating development of flood storage space in reservoirs and other
structural means to modify flood hazards, the Flood Control Act of 1936
expanded federal responsibility for flood control by public works
throughout the country. Local public agencies cooperated with the
federal government in local flood control projects: furnishing necessary
lands, easements and rights of way; agreeing to provide appropriate
maintenance; and holding the federal government free of liability. By
the mid 1960s about \$11,000,000,000 of federal investment for flood
control had been made. Nevertheless, lives and property continued to be
lost. Public and private expenses for relief and rehabilitation
continued to soar.

Reports by the National Planning Board as early as 1934 began to
question the wisdom of the concept of flood control and suggested the
alternative of restricting housing and other buildings from floodplains.
The Tennessee Valley Authority was the first federal agency to
experiment with non-structural means of reducing flood risks. Reports of
the President\'s National Water Policy Commission in 1950 and the
Presidential Advisory Committee on National Water Policy in 1955
recommended consideration of nonstructural measures in planning. It was
not until the 1960s, with publication of the very influential report of
the Senate Select Committee on National Water Problems and the report in
1966 of the Task Force on Flood Control Policy entitled \"A Unified
National Program for Managing Flood Losses,\" that modern concepts and
means of institutional response to natural flooding began to congeal.
Contemporary institutional concepts and means of coping with natural
flooding involves many types of institutions: federal, federal-state,
state, regional, local, public and private.

Federal

Numerous federal programs are available for assistance in flood hazards
and mitigation. Table 1, Federal Agencies Concerned with Flood
Mitigation, and a more comprehensive explanation in Appendix A
demonstrate this. Activity includes technical assistance and
information, programs for both structural and nonstructural measures,
and programs for emergency preparedness and disaster assistance.
Assistance available ranges from programs with very direct and easily
identified subject areas to more peripheral subjects, but all may have
significant impact on floodplain management and mitigation.

Table 1

FEDERAL AGENCIES

CONCERNED WITH FLOOD HAZARD MITIGATION

DEPARTMENT OF AGRICULTURE

Economics, Statistics, and Conservation Service Agriculture
Stabilization and Conservation

Service

Farmers Home Administration

Forest Service

Soil Conservation Service

DEPARTMENT OF THE ARMY

Corps of Engineers

DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

Economic Development Administration

DEPARTMENT OF ENERGY

Federal Energy Regulatory Commission

DEPARTMENT OF HEALTH, AND HUMAN SERVICES

Public Health Service

DEPARTMENT OF HOUSING AND URBAN DEVELOPMENT

Community Planning and Development Federal Housing Administration

DEPARTMENT OF THE INTERIOR

Bureau of Land Management

Heritage Conservation and Recreation Service

Geological Survey

Fish and Wildlife Service

Water and Power Resources Service

Office of Water Research and Technology

DEPARTMENT OF TRANSPORTATION

Coast Guard

Federal Highway Administration

FEDERAL EMERGENCY MANAGEMENT AGENCY

Disaster Response and Recovery

Federal Insurance Administration

Plans and Preparedness Mitigation and Research

NATIONAL AERONAUTICS AND SPACE ADMINISTRATION

NATIONAL SCIENCE FOUNDATION

SMALL BUSINESS ADMINISTRATION

TENNESSEE VALLEY AUTHORITY

WATER RESOURCES COUNCIL

Through the early years of this century the federal programs on floods
concentrated on structural approaches on major streams, utilizing
reservoirs, dikes, and channelization. During the 1970s there was an
increasing awareness of the environmental consequences of these actions
along with the growing acceptance of nonstructural approaches as a
viable planning alternative. This movement was aided by the realization
that in spite of the millions spent for structures to protect flood
prone areas, damages continued mount. Over the years flood related
programs have been authorized as part of many different federal agency
programs as explained above; and, ironically, nonrelated federal
programs were contributing to the flooding which some other federal
program was supposed to eliminate or minimize.

The most significant new program, authorized in l968 involved a
non-structural approach to floodplain management using flood insurance
as a means of limiting development or redevelopment in flood prone
areas. For this approach to be effective, it was recognized that all
related federal, state, and local programs must be coordinated. On May
24, 1977, following up on initiatives by previous administrations,
President Carter issued Executive Order 11988 calling on all federal
agencies to join in a coordinated effort to bring unity to federal
programs and to work with state and local counterparts to encourage a
more cost-effective approach to flood disasters and floodplain
management. Emphasis is placed on sound floodplain management to guide
future floodplain development and attempts to restore floodplains to
enhance their natural values. Three years of effort produced minimal
results. On December 31, 1979, President Carter addressed a memorandum
to the affected agencies directing them to redouble their efforts to
issue and promulgate regulations. The Water Resources Council is
monitoring the progress of implementation and submits reports to the
Executive Office periodically. The Council of Environmental Quality and
the Federal Insurance Administration, along with the Water Resources
Council act as consultants to the federal agencies in developing their
regulations to comply with E.O. 11988.

In the 1970s it became evident that disaster related programs located in
several agencies could be administered more effectively under one
management structure. This prompted the formation of a new executive
agency, the Federal Emergency Management Agency, and a shift of several
program responsibilities including flood insurance, emergency
preparedness, and disaster assistance. Other flood related programs,
like the structural programs of the Corps and the SCS are still separate
programs not under FEMA.

State Agencies

The responses of the states to flood hazard mitigation have been varied.
Generally, state input to the federal-local partnership promoting
structural solutions has been minimal. States have not provided either
the legislative or the institutional framework to accommodate or promote
integration of the structural solution into a more comprehensive
approach. Although there are exceptions, the prevailing water resources
development actions (projects) largely have been the result of federal
response to local requests for help. As federal policy has evolved from
controlling the floods (the structural approach) to managing actions in
the floodplains (the nonstructural approach), states have become more
active participants.

Zoning, one of the primary tools of a comprehensive floodplain
management or flood damage reduction program, is an exercise of the
police powers that reside in each of the sovereign states. State
enabling legislation, both for general zoning and for floodplain
management, is a prerequisite for determining the kinds of actions
undertaken at the state level or at the local level under authorities
delegated from the state. In some states floodplain, or only floodway,
permits are issued by a state agency.

Various types of enabling legislation for floodplain management exist.
Theoretically, approximately half of the states have floodplain enabling
legislation; some of them have sufficient authority to set technical
standards that meet their unique needs and to enforce their program
requirements when local units of government fail to do so. Although
these are not the only elements needed in a comprehensive state program,
they are part of the set of authorities needed to ensure success. Some
states have active pro-grams in which staff perform technical analyses,
develop program materials, assist local units of government in the
adoption and administration of regulations, and promote sound floodplain
management and flood hazard mitigation. In other states, floodplain
management exists \"on paper,\" if at all, and staff involvement is
limited to being the repository of correspondence relating to the
National Flood Insurance Program.

Effective floodplain management programs function best locally where
there are strong state programs to support them. This occurs because the
state can best provide assistance and enforcement of local ordinances
and provide a vital link for assistance and cooperation with federal
agencies.

Another area of state activity has involved agencies for emergency
services or disaster relief. Their actions traditionally have been
associated with disaster preparedness and relief operations. In most
cases, they have not considered hazard mitigation to be a part of their
duties; but it is likely that the implementation of Section 406 of the
Federal Disaster Relief Act of 1974 for hazard mitigation as a condition
of federal disaster assistance will result in the consideration of flood
mitigation in their operations. Another likely outcome of Section 406
will be better coordination among the state disaster relief agencies and
the state agency responsible for floodplain management.

If flood hazard mitigation is to succeed nationwide, it is imperative
that federal policies, programs, and funds support the state role. The
FIA has taken a step, through the State Assistance Program, to
strengthen the state role. The State Assistance Program is a grant
program whereby the states can apply for money to expand their present
floodplain management efforts. This program will allow active states to
go even further and, perhaps, develop more innovative approaches. Also,
it will provide financial incentive for less active states to assess
their present role and develop program strategies to meet their
individual needs. By recognizing and strengthening the state role, FIA
has enhanced the ability of all states to promote *and implement hazard
mitigation more effectively.*

Providing incentives to states to encourage adoption of adequate
legislation and program efforts is sensible. Strong state programs can
result in sound floodplain management at all levels of government.

*Local Communities*

*Community *responses *to flood *hazard *mitigation *measures vary
considerably: floodplain regulation and control of development, warning
plans prepared and rehearsed in anticipation of a flood, and proven
means of recovering after a flood event.

Where successful hazard mitigation occurred, it has almost always due to
a strong and sustained local effort. Especially important is that the
solution be perceived as \"their solution.\" With that realization, it
is imperative that federal programs, policies, and funding support
strong local efforts. These programs and policies must be implementable
and realistic.

Community attitude toward flooding is developed from the combined
attitude of the governing body and staff and pressure they receive from
citizens. They all must perceive a real flood problem and the need to
institute flood hazard mitigation measures. If this is the case the
organization can respond by developing approaches, hiring staff, and
taking other action. Perceived needs depend largely on how recently and
how seriously flooding has affected the citizenry. Many actions to
accomplish mitigation are not taken solely for purposes of hazard
mitigation. Local communities may think of them as urban and economic
development, community planning, or other such purposes.

A complicating factor in most urban areas is the multijurisdictional
characteristic of flooding. Warning systems might involve several
agencies and communities; the evacuation plan of one community may be
affected by what a neighboring community does or does not do; and
structural measures must be compatible from one community to the next.
Federal policies should encourage basin-wide hazard mitigation efforts.

The federal program with the most effect on local communities is FEMA's
flood insurance program, involving potentially* about *20,000
communities. Because of the flood insurance program, many communities in
the United *States *regulate or manage floodplain and coastal zone areas
to some extent.

Typically, FEMA uses an incentive approach. \"regulate the floodplain or
receive no federal assistance for acquisition and construction
activities in flood hazard areas.\" Ten years ago floodplain regulation
was not widespread. Today, many affected local governments are cognizant
of the need for such regulations and many nave adopted some form of
regulatory program. It is hoped that floodplain regulation will some day
be accepted by communities as commonly as are building codes, height
limitations, and liquor laws.

Local communities must possess *the *resources *and *basic *data to
select *the proper mix of alternatives to achieve flood hazard
mitigation in their situation. Federal programs or actions can supply
tools to successfully implement hazard mitigation in a community. These
could include block grants, redevelopment and economic development
programs, and programs to dovetail with this important effort.

Locally developed alternatives for flood hazard mitigation can
accomplish multiobjectives for local communities: flood hazard
mitigation; *economic development; reduced energy consumption; decent,
safe, and sanitary housing; reduced agricultural crop damage and soil
erosion; improved *water quality; and recreation and open space use by
people and the environment. After a local community has developed the
proper mix of alternatives, with help from state and federal lead
agencies, some mechanism must be established to assure complete and
continual funding for implementation. Too often when a community is
*ready to *implement *a nonstructural measure *there is not a commitment
for funding the federal partnership share. This has been true even
though *a *federal agency may have helped the community do the planning.
A strong local commitment will be needed, which always requires local
funding support. It is unreasonable to expect local communities involved
in cost sharing programs to take long-term financial responsibility when
the accompanying federal funding pledge is given one year at a time with
no assurance of continued future funding. Federal partnerships must
include an initial covenant for assistance with the entire project over
an appropriate period of years.

Private

Several nongovernmental or quasi-governmental agencies and groups have
significantly active programs to provide emergency assistance and
long-term aid to disaster victims. Also, some trade and industry
associations have become involved in providing assistance to members
affected by floods; and many groups earnestly are attempting to
influence hazard mitigation efforts.

The major national voluntary groups involved in emergency assistance and
relief and rehabilitation, and to some extent in advocacy programs
related to the plight of flood victims and to hazard mitigation efforts,
are members of the National voluntary Organizations Active in Disaster
which has existed for several years and was formally structured at its
annual meeting in 1978.

When a Presidential Major Disaster or Emergency Declaration is made,
efforts of voluntary groups may be coordinated by the Federal
Coordinating Officer at the scene, as provided for in Public Law 93-288.
To enhance such coordination larger agencies such as the American Red
Cross, the Civil Air Patrol, and the Salvation Army, have written
statements of understanding with the Federal Emergency Management Agency
which describe the working relationships. Many of them also have written
statements of understanding with the American Red Cross because of its
role as the primary, Congressionally-chartered, voluntary disaster
relief agency. The Red Cross responds to thousands of disaster incidents
annually that are not Presidentially declared, and hence do not involve
implementation of federal programs.

American Red Cross - An act of Congress approved in 1905 as amended,
constituting the American National Red Cross charter, requires the Red
Cross to undertake relief activities to mitigate suffering caused by
disaster and obligates the Red Cross to develop and carry out measures
to prevent suffering. The organization\'s Disaster Program includes many
kinds of assistance:

damage assessment; emergency shelters; registration; communications;
first aid personnel and stations; distribution of emergency supplies,
stationary and mobile facilities to feed victims and emergency workers;
supplementary medical and nursing care; blood and blood products;
welfare inquiries and information services; emergency financial
assistance for food, clothing, rent, bedding, selected furnishings,
transportation, medical needs, temporary home repairs, occupational
supplies and other essentials on an individual or family basis; referral
service to government and private agencies; and casework services to
provide additional recovery assistance when government programs and
other resources are not adequate to meet disaster caused needs. Red
Cross works through over 3000 local chapters supported by additional
personnel, equipment, material, and financial resources from 60
divisional and 4 regional offices, and national headquarters. Red Cross
assistance is an outright gift, funded from voluntary contributions.

Numerous other primarily religious organizations cooperate with
government at various levels, and typically with the Red Cross: Ananda
Marga Universal Relief Team, the B\'nai B\'rith, Christian Reformed
World Relief Committee, Church of the Brethren, Church World Service,
Menonite Disaster Service, National Catholic Disaster Relief Committee,
Salvation Army, Seventh-Day Adventist Community Services, Society of St.
Vincent de Paul, Southern Baptist Convention Home Mission Board, United
Methodist Committee on Relief, United Presbyterian Church USA, and
Volunteers of America.

Also, a variety of groups provide major support to emergency service and
disaster relief agencies, and particularly to the Red Cross: National
Defense Transportation Association, the Civil Air Patrol, AFL-CIO
Community Service, American Humane Society, American Legion, American
Society of Civil Engineers, American Radio Relay League, REACT, scouting
organizations, and Goodwill Industries.

Increasingly, some of the religious groups and the Red Cross are
becoming involved in public education efforts related to the National
Flood Insurance Program, land-use regulation, building codes, and other
hazard mitigation efforts. They also participate in and support
campaigns such as the Texas Coastal and Marine Council\'s Hurricane
Awareness program and work with Agencies on the Aging to educate elderly
persons in flood and storm related safety measures.

Finally, a large variety of organized conservation, consumer, and public
affairs groups are taking more interest in natural hazard problems and
ways to prevent or respond to damage created by such hazards.

Outstanding among these groups are the League of Women Voters, which has
had disaster preparedness and hazard mitigation as a major agenda item
for its local units, the Sierra Club, and the Environmental Defense
Fund. Also, insurance associations and banking organizations have been
intermittently active with flood problems, particularly those related to
implementation of the National Flood Insurance Program. Some of the
environmental groups have purchased floodplain or wetland properties and
dedicated them to nonhazardous use by deeding them to park, recreation,
and other similar agencies.