The purpose of a summary report is to show factually in a brief document the presence or absence of interstate pollution in an interstate water body; when present, its effect on water uses in the receiving State; its sources; and area affected - upper and lower limits. Summary reports will be used by officials of the Public Health Service and the Enforcement Branch in answering queries, frequently from Members of Congress. In addition, these reports will provide a basis for evaluating the need for enforcement action.