Spatial-data management techniques allow convenient, cost-effective representation of the spatially-varying data that are necessary for effective water and related-land resources planning. Application of the techniques began in the U.S. Army Corps of Engineers in the early 1970's as an experiment. Since then, the techniques have been used for regional planning studies, major flood-control studies, and limited-scope investigations. The HEC-SAM software, developed and supported by the staff of the Hydrologic Engineering Center (HEC), has made practical these applications. Keywords: Geographic information systems; Data bases.

The U.S. Army Corps of Engineers is using spatial data management techniques in studies that are structured in a manner that requires spatial data management techniques to play a central and dominant role. The Corps of Hydrologic Engineering Center (HEC) provided the basic developmental work on the spatial data management and attendant processing techniques and it is continuing in the role of the basic technology transfer agent. The significant efforts required to document, maintain and service the technology and provide ready consultation service reported herein were planned for during the developmental efforts and are currently being centrally managed to encourage smooth adoption of the techniques by Corps field offices. (Author).

Flood control and flood plain management investigations using spatial data management techniques are increasing in the Corps of Engineers. Pilot studies initiated in the mid-1970's were successful in consolidating analysis concepts, fostering the development of spatial data file creation and management technology and enhancing the consideration of existing and alternative future development patterns in Corps' planning studies. Over 30 studies using HEC-SAM, the Corps' spatial data management system, are now completed or underway. HEC-SAM was created through selective acquisition of commercial software, adaption of academic research products, and development by researchers at the Corps' Hydrologic Engineering Center (HEC). The HEC role continues to be that of system developer and technology transfer agent. The evolution, present capabilities, and applications of HEC-SAM are described. Observations are offered on spatial technology development, implementation, and servicing. (Author).

Water resources planning at the federal level is comprehensive multi-purpose multi-objective planning. The increasing complexity of issues, planning alternatives, and evaluation criteria have spawned an ever growing need for increased data and associated analysis procedures. The increased number of such models, both demanding and generating large amounts of data, have stimulated awareness of the need for planning oriented data management systems. This paper describes recent activities of the Corps of Engineers Hydrologic Engineering Center in data management for water resources planning studies.

The Corps' Hydrologic Engineering Center (HEC) has developed a generalized simulation model capable of analyzing complex river-reservoir systems. The development of the model, 'HEC-5, Simulation of Flood Control and Conservation Systems' (Eichert, 1974, 1975) has been paced by the changing mission of the Corps as well as the evolution of computer systems. HEC-5 development and management, including code development, testing, documentation, training and field application experience, is discussed. (fr).