FLOOD06078 - Laserfiche WebLink

Home Browse Search

No floodway was overflow occurs in inadequate channel computed the reach capacity. for Dry Gulch Creek because shallow from Delwood Avenue to the mouth due to The floodways presented in this study were computed for certain stream segments on the basis of equal conveyance reduction from each side of the floodplain. Floodway widths were computed at cross sections. Between cross sections, the floodway boundaries were interpolated. The results of the floodway computations have been tabulated at selected cross sections (Table 2). In cases where the floodway and lOO-year floodplain boundaries are either close together or collinear, only the floodway boundary has been shown. The area between the floodway and 100-year floodplain boundaries is termed the floodway fringe. The floodway fringe encompasses the portion of the floodplain that could be completely obstructed without increasing the water-surface elevation of the lOO-year flood more than 1.0 foot at any point. Typical relationships between the floodway and the floodway fringe and their significance to floodplain development are shown in Figure 2. I- lOO-YEAR FLOODPLAIN .1 FLOODWAY FRINGE << FLOODWAY FLOODWAY FRINGE STREAM ~ CHANNEL FLOOD ELEVATION WHEN CONFINED WITHIN FlQODWAY ENCROACHMENT AREA OF FLOODPLAIN THAT COULD BE USED FOR DEVELOPMENT BY RAISING GROUND FLOOD ELEVATION BEFORE ENCROACHMENT ON FLOODPLAIN LINE AB IS THE FLOOD ELEVATION BEFORE ENCROACHMENT. LINE CD IS THE FLOOD ELEVATION AFTER ENCROACHMENT, 'SURCHARGE IS NOT TO EXCEED' ,0 FOOT (FIA REQUIREMENT) OR LESSER AMOUNT IF SPECIFIED BY STATE. Figure 2. Floodway Schematic 14