A storm event occurred in a watershed that produced a rainfall pattern of 5 cm/h for the first 10 minutes, 10 cm/h in the second 10 minutes, and 5 cm/h in the next 10 minutes.

The watershed is divided into three subbasins (Figure 5. 35) with the 10-minute unit hydrographs (UHs) as specified in Table 5. 11. Subbasins A and B have a loss rate of 2. 5 cm/h for the first 10 minutes and 1. 0 cm/h afterward. Subbasin C has a loss rate of 1 cm/h for the first 10 minutes and 0. 0 cm/h thereafter. Determine the storm hydrograph at point 2.

Assume a lag time of 20 minutes.

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8.00 90 100 2539 TABLE 5.11 Inflow Hydrographs of Problem 7 Time (min) Inflow (L/s) ABC 0000 10 40 30 50 22% 20 30 70 110 65 100 80 105 41228 40 50 60 75 50 30 75 50 35 90 75 50 2222 70 80 20 20 7 35 218 10 20 10