1. Introduction

Over the last decade, hardly a year has gone by in which one or more Latin American countries have not been subject to extensive flooding. Floods disrupt economies, play havoc with public services, and often create the need for assistance from abroad. Economic losses, especially in agriculture, may be crippling for years.

The severity of these floods is often exacerbated when natural causes are compounded by deforestation, faulty dam construction, and other human alterations of the environment. Flash floods may result from these and other phenomena, such as hurricane sea surges and earthquake-related tsunamis. When flash floods do occur, the toll on human life can be heavy.

As a rule, however, the floods that have ravaged large areas of country after country have been slow in onset and prolonged in duration. As a result, it has been possible to warn endangered communities and to evacuate them if necessary.

Because of this characteristic of floods in Latin America, however, confusion and inefficiency have arisen in relief management. Accustomed to thinking of disasters as acute phenomena with a sudden rise in deaths and injuries, the international community often responds with costly medical equipment, teams of specialists, emergency medicines, and mobile hospitals. Yet even a superficial survey may show that there is no dry ground on which to erect the hospitals and there are no acute trauma cases that cannot be handled by local personnel. Press reports of "epidemics" in the early stages of the floods may prove to be equally unfounded, yet health authorities are pressed by public opinion to carry out emergency vaccination campaigns, aerial insecticide spraying, emergency food relief, and similar measures.

Paradoxically, because floods can last several months, the real hazards to health emerge as concern about addressing them is waning and international relief assistance is considered complete.

The inappropriateness of the timing and nature of relief assistance is in no small part due to the lack of a sound method for assessing needs. Needs vary according to whether the disaster is an earthquake, volcano, or flood, and according to the phase of the disaster.

Spirgi (1979) describes the following phases:

1. The impact phase: when the disaster strikes.

2. The emergency phase: when lifesaving measures are taken. This phase has been subdivided into:

- the isolation period:

when contact with the "outside world" has been broken and the community must rely on its own resources

- the "convergency" period:

when there is an outburst of assistance from outside-assistance that is often unsolicited and frequently useless, however well intentioned

3. The rehabilitation phase: when essential services are provided on a temporary basis. Here, emphasis is on environmental measures, sanitation, and provision of emergency shelter.

4. The reconstruction phase: which has been defined as the "time-phase of permanent return to normalcy."

In natural disasters of sudden onset, these phases are clearly marked; in slow floods, however, the boundaries are blurred. It may take months for the disaster to be recognized as such and for authorities to realize that an emergency exists. The isolation period may last for months, and rehabilitation and reconstruction may overlap with the next flood.

Dramatic, well-defined disease outbreaks are generally not found in the immediate aftermath of a flood. Instead a slower, widespread deterioration of general health conditions takes place, which all too often becomes part of a chronic lowering of the affected community's health status. The longer the flood lasts, the more likely risk factors will converge that can lead to epidemics. Unless the health sector is alert to this process, it may find an explosive problem on its hands long after the "emergency" has been declared over and external assistance has ceased.

What, then, is the best way to safeguard the health of the affected population and make good use of relief supplies? When are what measures called for?

Strategic information gathering is critical to making these decisions. Although data are routinely collected by national and foreign personnel involved in relief and rehabilitation efforts, the selection process is rather subjective, and as accurate as the individual in charge is experienced. Over the years, the number of people with that experience has grown. Yet their approaches to selecting reliable indicators of health needs have not been systematized in writing.

There is, therefore, a marked need for a standard methodology for the rapid assessment of needs. If applied, such a method should make it possible to take sound short-term measures and-more important in the event of floods-to set up a longer term monitoring system for alerting health authorities to delayed risks.

From experience we know that a flood's major effects on health are in four main areas: certain communicable diseases, environmental sanitation, food and nutrition, and vectors. Ideally, therefore, the assessment team sent from a central level should comprise an epidemiologist, a sanitary engineer, a nutritionist, and an expert on vector control. If the stricken country relies heavily on an international or bilateral agency for assistance, then a technical officer of that agency should be part of the team. However, the goal should be for the countries to develop their own expertise in this field-a goal that can be achieved by developing the right method for damage and needs assessment and by training others in that method.

This publication, which was authored by Dr. Miguel Gueri, is a step toward that end. It presents a methodology for selecting the appropriate data from the proper sources. The method is based on the premise that, although each flood has its own peculiarities, there are common key decisions that must be made.

Given the political nature of emergencies, these decisions will be made, right or wrong. The adoption of a standard rapid assessment methodology should provide the basis for improving the record by moving the decisionmaking process into a sound technical realm.

In practice, the assessment team referred to throughout is often only a single individual. Although the world "team" is used here, the method described can be applied effectively by one person if he or she enlists the aid of others who can help supply the required information.

This first contribution toward a standard method for assessing health needs after floods should be treated as a working document; gradual refinements can only move national and international relief and rehabilitation efforts more quickly into an age of informed effectiveness.

Although slow-onset floods are the main subject here, the same approach can be applied generally to hurricanes when, as is often the case, the winds usher in torrential rainfall. The major differences are that in hurricanes the isolation period is shorter, the geographical extent of the affected area smaller, and, in the case of some islands, the need for food relief more immediate and acute.