Severe flooding threatens several counties in a Midwestern state. A district director for the state public health department is the field supervisor for the emergency. In the state capital, a deputy state public health officer coordinates logistical support and serves as the primary liaison to the Federal Emergency Management Agency.
At the center of the emergency response operations is a shared GIS database of the state which includes detailed geographic information about the population, buildings, state and county offices and facilities, transportation systems, water systems, and wells. Projections from the National Weather Service, which are used to update the database, indicate the probable areas that will be inundated in the next 24 hours. The actual progress of the river is documented by aerial photographs that are scanned and calibrated using physical features already represented in the database. Emergency workers in the field use global positioning systems (GPS) to determine the locations of particular problems, such as impassable roads and bridges, which are difficult to pinpoint in a flood.
The linking of data from weather service projections to the GIS database indicates that the flood is likely to require the evacuation of about 15,000 residents within the next 24 hours, to inundate town water systems and wells serving about 30,000 residents, and to temporarily close at least one district public health office. Invoking a decision-support algorithm, the district health officer develops a plan for allocating district public health personnel and emergency supplies. At the state capital, the deputy state public health officer makes arrangements for the National Guard to dispatch water and amphibious vehicles to a staging area near the region that will be affected first. As the evacuation occurs, regular updates from the field allow appropriate modifications in support and the development of an improved plan for the next 24-hour period.