1) (18 points) Pumping tests are being used to determine the hydraulic conductivity and the storage coefficient in aquifers. Consider a confined aquifer that is about 10m thick. A well is being pumped at a rate of 15m3/min for 10 days and the hydraulic head at an observation well located 100m away is being monitored during this period. Use the Jacob method (described in R.C. Heath, 1982, p 38/39) to determine transmissivity, hydraulic conductivity, and the storage coefficient for the aquifer.
a) (4 points) Download the data(.csv file) and convert it into an EXCEL file and store under JACOB.XLS. The initial hydraulic head in the aquifer at the observation well was 2 m below the surface or 20 m above sea level. The file contains the hyraulic head data (in m above sea level) for the observation well as a function of time from the start of the pumping test. Convert the hydraulic head data into drawdown in meters and plot drawdown as a function of time with drawdown = 0 in the upper left corner. Describe the pattern that you see. When does the fastest drawdown occur? Print the plot.
b) (6 points) Make another plot similar to the one shown in Heath, p 39. Click the x-axis and change it into a logarithmic scale. Print the plot, it should look kind of similar to the one in the book. Use a ruler and a pen to manually determine delta S and to.
c) (6 points) Determine the transmissivity (=hyraulic conductivity * thickness of the aquifer), hydraulic conductivity, and storage coefficient from the formulas given on page 38/39.
d) (2 points) Based on the
values,
what kind of rock does the aquifer consist of (see Fig
6.5)?
Heath, R.C (1982) Basic Ground-Water Hydrology. United States Geological Survey Water-Supply Paper 2220, 84p.
(supplied by M. Stute to the BC library to keep. Also available as PDF file (complete document) or PDF file of pages 38/39 only.)
