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conditional approval ofthe Federal Insurance Administrator is first obtained. The Developer should initially attempt to reduce the surcharge to the base level. This may be accomplished by evaluating alternatives such as widening the floodway or other conveyance modifications described in Sedion 4-2 to compensate for loss of conveyances caused by the proposed development. If the rise cannot be entirely negated, but the water surface profile elevation is within the surcharge limit, the developer must request a floodway revision as defined in Sedion 4-3. If the developer demonstrates that an unavoidable increase in the profile elevation above the surcharge limit results from the development, a request for a conditional map change must be made. Basically this requires the following: 1. A request for conditional approval of the map change and the ap- propriate initial review fee if applicable. 2. An evaluation of alternatives which would not result in a flood elevation increase above the allowable surcharge limit. This evaluation should demonstrate why these alternatives are not feasi ble. 3. Documentation of individual legal notice to all impaded property owners within and outside of the community, explaining the impact of the proposed adion on their property. 4. Concurrence of the Chief Executive Officer of any other communities impacted by the proposal. 5. Certification that no strudures are located in areas which would be impaded by the increased base flood elevation 6. A request for revision of the base flood elevation and the f100dway. Upon receipt of the Administrator's conditional approval of map change and prior to approving the proposed encroachments, the community must provide evidence to the administrator of the adoption of floodplain manage- ment ordinances incorporating the increased base flood elevations and/or revised floodway refleding the post-projed condition. Finally upon comple- tion of the proposed encroachments, the community must provide as-built certifications. A final map revision is then initiated upon receipt of the certification. 5-2. Downstream Side of ExistingStrudure. A small addition to strudure may be acceptable jf it is construded on the downstrearr strudure within the flow patterns shown in Figure 4. However, the of losses and flow patterns around buildings and other obstn complex, espeCially in urban areas. The developer may be requir that the assumptions as shown in Figure 4 are applicable to th, development location and that no rise in the base flood will occu - - 2g:...... - -- - PROPOSED EXISTING ADDITION STRUCTURE , , , , , 20'...... POSSIBLE DEVELOPMENT ZONE 5. Examples of Floodway Development S-l. Overview. This section overviews typical development proposals for f100dways and describes basic analysis considerations and requirements for submittal for approval. The adual conditions may necessitate a variation in analysis procedures and requirements. In general, approval for proposed developments in the floodways is contingent on demonstration that the projed will not result in a rise in the f100dway profile. Specific criteria and adions are described in Sedion 6. 1 I Figure 4: Development Downstream Side of Stru If it can be shown that the flow patterns are such that the devE on the downstream side, the flow patterns are not significantly intE by other obstrudions, and that the addition is relatively small, tl may be approved without detailed water surface profile analysis. for this condition the proposed development must be located flowline shadow of the existing building conceptualized by 20 de with the downstream corners of the building. For complex areas where the flow patterns are affeded by sevel tions, more complex hydraulic modeling and analysis may be I demonstrate that no rise in the base profile will occur. 5-3. Relocation of Channel Alignment. Development within th areas may include realignment of the existing flow conveyano floodway delineations. Figure 5 shows an example of a realig, 10