U.S. Department of Defense


Date of this Version


Document Type



The minimum unambiguous citation for this document is: EIG 32, 1961.


This digital copy of EIG 33, 1961, was provided by the US Geological Survey, National Center.

According to the OCLC record for this document (Accession No: OCLC: 27694922), the corporate author of this document is the Army Map Service and it was published in 1961.

Engineer Intelligence Gudes (EIGs) were intended to distribute “intelligence collection, processing, production, and dissemination guidance” to “elements of the Corps of Engineers.” In 1961, the Army Corps of Engineers was one of the Army Technical Services, a bureau providing numerous services to the US Armed Forces including preparation of intelligence concerning geography and mapping.

Since the army often reused document numbers and titles, the date must be included to unambiguously identify any given army publication.


Despite the title, this engineer intelligence guide (EIG) is a photo-interpretation handbook. It was intended to help photo-interpreters recognize streams, rivers, lakes, and other hydrologic features. The introduction says that the purpose is:

a) To give “the officer responsible for furnishing hydrologic and hydraulic data in an assigned area … an understanding of the usefulness and limitations of photography in furnishing the type of information needed …,” and to assist in planning requests for photographic coverages of the assigned area.

b) To give “photo-interpreters sufficient knowledge of hydrology and hydraulics to be able to satisfy requests for information that can be secured from photographs and become aware of the need for communicating changes in … conditions, such as, breaks in levees, sudden drawdown or filling of reservoirs, rising water in rivers, and formation and breakup of ice jams…”

It contains extensive guidance in preparation of requests for photographic missions.

It contains detailed information on the value of photographs as sources of hydrologic and hydraulic data.

This EIG contains detailed information with extensive illustrations to assist in interpretation of hydraulic characteristics of watershed, hydraulic characteristics of streams, and of hydraulic structures such as dams, hydroelectric plants, canals, irrigation systems, flood control structures, etc.

It contains a bibliography of literature related to military hydrology and the application of aerial photography to understanding hydrologic features.

It contains an lengthy distribution list of officials and organizations within the Army interested in military engineering.