Exercise 1
A 0.2 m diameter production well finished in a confined sand aquifer was pumped continuously at 300 L/minute for 10 hours. The water levels in the pumping well and two observation wells appeared to stabilize at about 6 hours as shown in this image.
Cross section of a confined sand water bearing unit. The production well is pumped at a constant rate of 300 L/min for 10 hours and the drawdown in two observation wells is observed under what appear to be steady state conditions. Drawdowns from the static pre‑pumping water levels are shown along with the radial distances of wells from the production well.
- Assuming the pumping test reached steady state or pseudo steady state by 10 hours compute T and K.
- Do you need to account for the effects of partial penetration on the observation well data? Why or why not?
- Assuming the production well radius is 0.1 m and the measured drawdown in the pumping well is 24 m, calculate the production well efficiency (i.e., measured drawdown divided by theoretical drawdown). A semi‑log plot of drawdown (arithmetic scale) versus distance (log scale) using the observation well data will be helpful.