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).