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I I I I I I I I I I I I I I I I I I I 1500 1400 1300 1200 1100 1000 0 z 0 900 .......... 0 \ ILl I VI \ a: 800 I ILl \ Q. I- 700 I \ ILl ILl 0 Il.. - \ 0 600 I \ - III /- :J I / ' ..... 0 ".s- O z 500 \. I \ \ ~ \ 0 400 I \ \ --l \ Il.. \ I \ \ 300 I '\ "- 200 If " ............ ..... ..... p ...... 100 A 0 0 1020 40 60 80 100 120 140 160 180 200 TIME, MIN., FROM BEGINNING OF STORM lO surface flows which would occur in a lOO-year flood after con- struction of the proposed facilities as shown on the plan sheets. Location: Miller Street and l4th Avenue (Dry Gulch) Hydrologic Characteristics Under Present Channel Conditions: Because the culverts which convey Dry Gulch under Colfax Avenue at this location are inadequate, ponding occurs in relatively frequent storms (approximately two-year floods or greater). In lO-year and lesser floods, the ponding is contained within the low-lying area. The lOO-year flood ponds to a depth which causes surface flow north across Colfax and eastward along Colfax. Hydrologic Characteristics After Implementation of the Master Plan: A new culvert will carry the lO-year flow under Colfax without ponding. The lOO-year flood will pond slightly, but will not reach Colfax Avenue. Therefore, flows reaching Dry Gulch north of Colfax would be greater than those which would presently occur, in all floods of 5- year or greater magnitude. Location: Garrison Street and Colfax Avenue FIGURE m-3 COMPARATIVE HYDROGRAPHS OF FLOODS REACHING THE INTERSECTION OF COLFAX AVENUE AND GARRISON STREET AFTER CONSTRUCTION OF RECOMMENDED FACILITIES Hydrologic Characteristics Under Present Channel Conditions: Dry Gulch consists of a system of small culverts crossing under Colfax Avenue in a southeasterly direction. The