It is important that scientific research on physical systems and applied research on the development of design procedures should both contribute to narrowing the gap between research and practice in flood estimation. The contribution of applied research would be aided by better information on current needs and practice, wider recognition of the economic importance of small rural and urban watersheds and of problems with geomorphological measures used in design relationships, and the use of identical procedures and measures in derivation and application of methods. For scientific research, some aspects of the use of the computer have been counterproductive. Several problems related to both types of research also contribute to the gap with practice. These concern current trends in data storage, inadequate information on accuracy of data, regional differences in flood characteristics, and various common assumptions that need to be challenged and evaluated. Inadequate attention has.been given by researchers to several problems of considerable importance to practice.