Introduction to Hydrogeology

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1. A well that is screened in a confined aquifer is to be pumped at a rate of 165,000 ft3
   /day for 30
   days. The aquifer transmissivity is 5320 ft2
   /day, and the storativity is 0.0007. What is the
   drawdown at distances 50, 150, 250, 500, 1000, 3000, 5000, and 10,000 ft? Plot the computed
   distance-drawdown data on a semi-log paper.
2. A well that is screened in a confined aquifer is to be pumped at a rate of 165,000 ft3
   /day for 30
   days. The aquifer transmissivity is 5320 ft2
   /day, and the storativity is 0.0007. Computer the
   drawdown at a distance of 100 ft at the following times: 1, 2, 5, 10, 15, 30, and 60 minutes; 2,
   5, and 12 hours; and 1, 5, 10, 20, and 30 days. Plot the computed time-drawdown data on a
   semi-log paper.
3. You are asked to design a pump test for a confined aquifer in which the transmissivity is
   expected to be about 1.4 × 10-2 m2
   /s and the storativity about 1.0 × 10-4
   . What pumping rate
   would you recommend for the test if it is desired that there be an easily measured drawdown of
   at least 1 m during the first 6 hours of the test in an observation well 150 m from the pumping
   well?

Sample Solution