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DR~FT TABLE 2.11 - ONE-HOUR RAINFALL VOLUMES ---------------------------------------------------------------- Return Period (Years) Rainfall (Inches) 2 0.62 5 0.83 10 25 0.96 1.20 50 1. 38 100 1. 57 TABLE 2.12 - ONE-HOUR STORM RAINFALL DISTRIBUTION ---------------------------------------------------------------- TIME RAINFALL INTENSITY (INjHR) (MIN) 2-YR 5-YR 10-YR 25-YR 50-YR 100-YR ---------------------------------------------------------------- 5 0.17 0.10 0.12 0.14 0.17 0.19 10 0.22 0.30 0.35 0.43 0.50 0.57 15 0.37 0.50 0.58 0.72 0.83 0.94 20 0.45 0.60 0.69 0.86 0.99 1.13 25 0.67 0.90 1. 04 1. 30 1.49 1.70 30 1.19 1.59 1.84 2.30 2.65 3.01 35 2.45 2.89 3.34 4.18 4.80 5.46 40 0.89 1. 20 1.38 1. 73 1.99 2.26 45 0.52 0.70 0.81 1.01 1.16 1. 32 50 0.45 0.60 0.69 0.86 0.99 1.13 55 0.30 0.40 0.46 0.58 0.66 0.75 60 0.15 0.20 0.23 0.29 0.33 0.38 ---------------------------------------------------------------- Results The results of the local drainage peak discharge determinations are provided in Tables 2 .13a through 2 .13r. These tables list both the exsting flows and future flows side by side for comparison. The watershed delineation and individual units are shown on Plates 3 through 12. The area modeled was divided into a total of 18 separate basins. There were seven small basins on the east side of the Blue River designated E-l through E-7. There were also seven small basins on the west side of the Blue River designated W-l through W-7. Four larger basins were modeled. These were Jones Gulch, Sawmill Gulch, Lomax Gulch and the Klack. For the main channel of Sawmill Gulch, the peak discharges defined by FEMA are substituted in the table. The results listed in Tables 2.13a through 2. 13r are used in sections XV and XV to answer questions such as where detention would be useful from a flood control standpoint, what existing components of the storm drainage system are inadequate and a general assessment of the drainage system. 22