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I I I I I I I I I I I I I I I I I I I 1. The East Fork drains into a 24-inch CMP storm sewer inlet at ford Street. Major flows continue down Ford Street with numerous businesses and residential properties affected. The approximate alignment of the existing storm sewer is shown on Sheets 9 and 18. 2. The grated intake immediately upstream of 21st Street becomes blocked frequently. The main flow path separates from Ford Street at this point and passes through a residential area to its confluence, with the main stem of Kenneys Run at 20th Street (Sheets 9 and 18). 3. A portion of the floodwaters which overtop Old Golden Road at cross section No. 205 will become hydraulically disconnected for the main flow path. These floodwaters will continue down Jackson Street and join West Fork floodwaters. The area between the East and West Fork floodplains is designated as a shallow flooding area. 4. The existing Interurban Railroad grade and the 24-inch clay pipe crossing structure will cause floodwaters to backup on the south and west side of the embankment. Excess flows will overtop the embankment and be conveyed by a limited capacity ditch between Old Golden Road and the railroad embankment. When the ditch capacity is exceeded, flows will inundate Old Golden Road and adjacent areas. The ditch flow area has been designated as such on Sheets 18 and 19. An estimated 300 cfs will be carried by the old railroad ditch as indicated in Table V. 5. The low capacity 24-inch RCP culvert under the Boys School Road forces road grade overtopping. The overflow area downstream of the crossing is shown on Sheet 19. Floodplain and F100dway Data The Flood Hazard Area Delineation plan and profile drawings show the outline of the 100-year flood event for present channel and floodplain conditions. The drawings are supplemented by Table V, "Floodplain and F100dway Reference Data" . The table contains a listing of descriptive information, 100-year flood discharges, stream stationing, thalweg elevations, 100-year flood elevations, and 100-year floodplain widths and average channel velocities at cross sections used in the study. The floodway data in this table defines an area required to convey the 100-year flood without causing significant increase in stage or velocity due to future development outside the established floodway. The floodway was determined based on criteria specified by the Urban Drainage and Flood Control District which allows a maximum rise of 0.5 feet on the energy grade line, assuming equal conveyance reductions on both sides of the floodplain. The floodway is a high hazard area characterized by relatively deep water and high flow velocities and should remain free of any development which would obstruct flow. The f100dway data tabulated presents f100dway widths to the right and left of the channel centerline, the total f100dway width, the mean velocity in the f100dway, and the 100-year flood elevations resulting from flows being confined to the f100dway. Flood Velocities Maximum flow velocities characteristic of a 100-year flood event are tabulated at typical cross sections on the water surface prlfi1e sheets. Average channel and floodway velocities are tabulated in Table V for each cross secti on. 22