53:078 Principles of Hydrology (Spring 2004)
Problem #15
Rainfall Excess Using the SCS Method for the NB Ralston Creek (July 1972 storm)
Compute the rainfall excess (direct runoff) for the North Branch Ralston Creek watershed (drainage area of 3.01 sq mi) for 17-18 July 1972 storm using the SCS method. Use the areal-average precipitation estimated using the Thiessen Polygon method (this is provided). Assume that the SCS runoff curve number (CN) is 82. Compute the following:

  1. Total storm precipitation (in inches)
  2. Cumulative rainfall hyetograph (in inches) (i.e., the mass curve)
  3. Rainfall excess (Pe) hyetograph (in inches) [round-off to 2 decimal places]
  4. Cumulative abstraction (Ia+Fa) (in inches)
  5. Depth of direct runoff (rd) (in inches)
  6. Volume of direct runoff (Vd) (in acre-feet)
  7. Effective storm duration (tr) (in hr)
  8. Runoff coefficient (C)
Last changed on 03/22/04 by aab.