Topic 5- SP 5A - Develop a Unit Hydrograph

Attached on Brightspace is the streamflow record from the Los Angeles County Department

of Public Works for Alhambra Wash above Klingerman St. in Rosemead, CA, for January 23 to

24, 2021. Alhambra Wash drains a primarily urban area from Pasadena through El Monte and

has a watershed area of 15.2 square miles (9,728 acres).

a)

Perform baseflow separation; you may assume a straight line from the starting flow to the

ending flow in the record. Determine the direct runoff volume, and the direct runoff depth,

inches, from the total watershed.

b)

Using all of the data (roughly 15-min increments) develop the ordinates for a unit

hydrograph.

c) Using the ordinates from "b)" select the flow values at 1 hour time periods, in even hours,

since the start of the storm flow (5:00 pm on January 23, 2021) as your unit hydrograph

and plot it. It will be used in follow-on problems.