Geology 127 (Hydrogeology)

California State University, Sacramento

Week 2: Water resources in the Central Valley, event hydrographs, baseflow recession, gaining and losing streams


Upon completion of this unit students should be able to:

  • Discuss the competing interests in California's water
  • Understand the concepts of baseflow and baseflow recession
  • Construct a stream hydrograph, and use the hydrograph to describe seasonal variability or flood events.
  • Describe the geologic factors that influence the shape of a recession curve.
  • Distinguish between a seasonal recession curve and a flood hydrograph.
  • Analyze a storm hydrograph to separate baseflow from storm input (determine the duration of overland flow).
  • Describe groundwater flow patterns for gaining and losing streams.

Reading Assignments:

Fetter, pp. 37-52

Class notes:

Lecture 3

Homework Assignment: base flow and stream flow

Homework assignment:  Fetter, 4th ed., pp. 62-64, # 9, 10

#9) The flow of a river at the start of a baseflow recession was 712 m3/s; after 60 d the flow declined to 523 m3/s.

  a) What is the recession constant?

  b) What would the flow be after 112 d?

#10) Assume that the hydrograph in Fig. 2.15 (Fetter, 4th ed,. p. 46) has a drainage basin of 722 mi2.  How long will the overland flow continue after the flood peak passes?

Homework solution: Click here for homework solution:

Due Date:  Monday, Sept. 10 at the start of class

Show your work to get partial credit!