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" . . . ADMINISTRA TIVE ASPECTS OF FLOODW A Y REVISIONS WITH HEC-2 David J. Greenwood, P.E. Michael Baker Jr., Inc. Consulting Engineers Alexandria, VA 22314 BACKGROUND The HEC-2 computer program has become the primary method for development of most flood ways in the country through the National Flood Insurance Program (NFIP). The NFlP itself has matured and will soon be completing all cost-effective, first-time Type 15 studies for communities across the nation. As a result, the role of the NFlP will change to what has been called a maintenance mode where the focus is on keeping the NFIP maps up to date. This will also result in changes in the use and application of the HEC-2 program in floodplain mapping and floodway delineation. INTRODUCTION In the future, we will see much more refinement, on a micro scale, to previously developed floodway boundaries. This will come about as a result of the shift to small scale revisions, limited map maintenance program studies, and the ever-increasing pressure to develop along and in the nation's floodplains. As our technology advances, we will closely examine the basic assumptions built into the existing modeling techniques used to develop the floodway models, as well as the basic premises of the technical aspects of the hydraulic modeling used. This is evidenced by the need and interest of this conference for HEC-2. We, as the nations technical specialists in the areas of hydraulics and hydrology, must also keep in mind the administrative side of our work. This will make our end product more usable by the public-and will also help assure that we maintain the trust the less- teChnically-informed public has in our profession. Therefore, it is the intent of this paper to flow chart (Figure 1) the administrative decision process we should follow in revising or developing flood ways with HEC-2 or other models. 1