Problem 3. The curve number (CN) of a small watershed is 81. According to historical data, the unit hydrograph (time unit t = 2 hour) has been derived and is given below. During a 6-hour rainfall event, a rain gage recorded a total precipitation of 1 inches with the following temporal distribution: 0.2 inch from hour 0 to 2, 0.5 inch from hour 2 to 4 and 0.3 inch from hour 4 to 6. Please develop the direct runoff hydrograph of this storm event. Table. The Unit-Hydrograph (for 1 inch of rain pulse) Time (hour) Unit Hydrograph (ft/s) 2 200 4 800 6 400 8 100 10 50 You can work with this table: Time (hr) 2 4 6 Rainfall hyeto, I (in) 0.2 0.5 0.3 P Pe le Time (hr) UH (cfs) Q (cfs) 2 200 4 800 6 400 8 100 10 50 12 14