Geology 210

Aquifer Characterization

 

California State University, Sacramento

 

Week 3

 

- Slug tests, data loggers and pressure transducers

 

Objectives:

Upon completion of this unit students should be able to:

  • Service and calibrate vented and non-vented pressure transducers

  • Start, stop and modify a test using a Solinst levelogger

  • Describe the advantages and disadvantages of slug tests

  • Estimate the displacement that a slug will have in a particular well

  • Use pneumatic or physical slugs to conduct slug-in and slug-out tests

  • Evaluate slug tests using Hvorslev and Bouwer and Rice methods

 

Reading for week 3:

Your readings and references this week come from several different sources:

 

1) Fetter, 4th ed., pp. 190-205

    Fetter, 3rd ed., pp. 243-256

 

2) Literature on slug tests:

 

Hvorslev, M.J, 1951, Time Lag and Permeability in Ground-Water Observations, Bulletin 36, US Army Corps of Engineers, Vicksburg Mississippi, 55 p.

 

Hvorslev, 1951

 

Bouwer, H., and Rice, R.C., 1976, A Slug Test for Determining Hydraulic Conductivity of Unconfined Aquifers with Completely or Partially Penetrating Wells, Water Resources Research, v. 12, pp. 423-428

 

Bouwer and Rice, 1976

 

 

Activities:

Morning activities:

  • Collect slug-in and slug-out data using Solinst levelogger data loggers

 

Afternoon activities:

  • Return to Placer Hall, and evaluate slug tests using Hvorslev and Bouwer and Rice methods.

Semi-log paper for slug test analysis


Slug test data:

MW-1 4 ft slug

MW-1 7 ft slug

MW-1 7 ft slug b

MW-1 7 ft slug c

MW-3 4 ft slug

MW-3 7 ft slug

MW-1A 4 ft slug

MW-3A pressure test

 

Assignment for week 3:

Estimate hydraulic conductivity in the shallow aquifer using Hvorslev and Bouwer and Rice methods.  Show your work. 

 

Answer this question in 5 pages or less (cover letter to the client and figures are extra, and may go beyond 5 pages).  Please double space your report, with normal margins and standard font (times or arial).  Refer to all figures in the text.  Citations are optional.  Use appropriate technical writing style, and include the following sections in your report:

 

Cover page (letter to the client):  Provide a cover letter and company logo that introduces your report to the client.

 

Introduction and purpose: Evaluate hydraulic conductivity in the shallow water-bearing interval.

 

Hydrogeologic setting: Geologic, hydrologic, land use, construction, hazards, etc. as appropriate.  Which wells did you use?

 

Methods: Field methods, type of slug used, length and displacement of slug, graphical methods, brief summary of Hvorslev and Bouwer and Rice methods and assumptions.  Compare two wells, and use two methods of analysis for each (Hvorslev and Bouwer and Rice).

 

Results: Summarize results. 

 

Conclusions and recommendations  Based on slug test results at the CSUS wellfield, what is your estimate of hydraulic conductivity (K) in the shallow water-bearing interval?

Due date: Saturday, Aug. 18