Geology 127 (Hydrogeology)

California State University, Sacramento

Week 10: Thiem equation (steady-state flow, drawdown estimates using two observation wells); partial penetration, well interference, flow boundaries, image wells


Upon completion of this unit students should be able to:

  • Distinguish between steady-state and non steady-state flow.
  • Estimate drawdown using the Thiem equation: steady-state flow, two observation wells.
  • Discuss the problems with an analytical solution for non steady-state flow in an unconfined aquifer.
  • Use a mathematical definition for partial penetration.
  • Estimate drawdown with more than one extraction well in the zone of influence.
  • Define constant head and no flow boundaries in a model.
  • Create image wells to model injection, withdrawal and flow boundaries.


Reading Assignments:

Lecture 14: Fetter, pp. 188-190, 207-209

Lecture 15: Fetter, pp. 163-189


Lecture notes:

Lecture 14

Lecture 15



Homework Assignment:

Homework Assignment: 
Topic: Steady state flow in a pumped well with two observation wells- confined and unconfined solutions.

Assignment: Fetter, p. 148 #9, p. 216, #1, #13

Due date: Monday Nov. 5

Homework solution:

Fetter, p. 148 #9 and p. 216 #1, #13


  • 10 points: List all equations and conversions, draw a diagram if requested in the problem.

  • 20 points: Calculations, substitutions, conversions

  • 20 points: Obtain correct answer, including conversions and correct use of significant figures (subtract 2-5 points for each math error or incorrect use of significant figures).