Determining Ground Water System Well Losses

Determining where significant decreases in head losses in a ground water system is useful to improve future designs as well as giving information on well rehabilitation, pumping plans, etc. The term, "ground water system" is used to include the well, surrounding sand filter and aquifer. The step drawdown test has been suggested to separate linear losses from turbulent losses, the latter being assumed attributable to the well screen and the former to the aquifer. However, it has been shown that this is not always accurate. A recent simulation model gives insight into these losses and is useful in well design. It can also aid in determining well losses in existing wells. This model is explained and an example given from an actual production well.