4.3 Chapter Summary

Before initiating technical studies to model a reach of river, the engineer should develop a detailed outline of the hydraulic study to assist in establishing a defensible time and cost estimate and to serve as a guide in processing the technical study. Floodplain modeling almost always includes the steps itemized in this chapter to model base, or predeveloped, conditions. A key factor in the technical outline is whether or not a hydrologic model is needed to develop the peak discharges and complete hydrographs throughout the study watershed. Flood profiles and flooded area maps for the base condition of the river are the prime result of this work and may be used to estimate the potential flood economic damages. Various measures to reduce the severity of flood damages, such as reservoirs, levees, or channelization, can be simulated with hydrologic or hydraulic models. Conversely, nonstructural solutions, including floodway analysis, floodproofing, and relocation, which serve to reduce damages rather than to modify the stream system, may be examined. The technical report describing the hydraulic studies should not be overlooked. Adequate time and funds should be allocated to ensure that a high quality technical report is prepared for independent review and to document the analysis.