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hazardous velocities are not produced~ study was based on a surcharge limit of the City of Brush in their November 16, The floodway used in this O~5 foot, as recommended by 1976 letter. The floadway for this study was computed on the basis of equal conveyance reduction from each side of the flood plain. The results of these computations are tabulated at selected cross sections for each stream segment for which a floodway is computed (Table 1). AS shown on the Floodway Map (Exhibit 3), the floodway boundaries were determined at cross sections; between cross sections, the boundaries were interpolated~ Where the floodway and flood bound- aries coincide, only the floodway boundary has been shown. The area between the floodway and the boundary of the 10Q-year flood is termed the floodway fringe. The floodway fringe thus encompasses the portion of the flood plain that could be completely obstructed without increasing the water-surface elevation of the IOO-year flood more than 0.5 foot at any point. Typical relationships between t~e floodway and the floodway fringe and their significance to flood plain development are shown in Figure 5. I~ 1 aO-YEAR FLOOD PLAIN -, FLOODWAY FRINGE FLOODWAY FLOODWAY FRINGE STREAM CHANNEL FLOOD ELEVATION WHEN CONFtNED WITHIN FLOODWAY AREA OF FLOOD PLAIN THAT COULD BE USED FOR DEVELOPMENT BY RAISING GROUND FLOOD ELEVATION BEFORE ENCROACHMENT ON FLOOD PLAIN LINE AB IS THE FLOOD ELEVATION BEFORE ENCROACHMENT. LINE CD IS THE FLOOD ELEVATION AFTER ENCROACHMENT. ~SURCHARGE IS NOT TO EXCEED 1.0 FOOT (F1A REQUIREMENT) OR LESSER AMOUNT IF SPECIFIED BY STATE. Figure 5. Floodway Schematic 11