The incremental rainfall data in the table were recorded at a rainfall gage on a small urban parking lot of 1 acre. Be careful to use a 0.5-hr time step and record intensity in cm/hr.
(a) Plot the rainfall hyetograph.
(b) Determine the total storm rainfall depth (inches).
(c) If 100 percent of the rainfall occurs as runoff and the time base of a triangular hydrograph (flow rate vs. time) is 3 hr, find the peak flow of the hydrograph in cfs. Be careful with units.
First find the volume of rainfall, and then equate it to the area under the hydrograph.
Time (hr)Rainfall (cm)
0 .................................. 0
0.5 .............................. 5.0
1.0 .............................. 5.5
1.5 ............................ 10.0
2.0 ............................ 12.0
2.5 ............................. 10.0
3.0 .............................. 4.5
3.5 .............................. 3.0
4.0 ............................... 2.5
4.5 ................................ 0