UBC Theses and Dissertations
A digital model of fluctuations in wells produced by fluctuations in nearby surface waters McTaggart-Cowan, Gillian Hope
Fluctuation of water levels in wells due to fluctuations of the nearby surface water (by tides, ships, dams) interfere with well analysis by standard field techniques. Therefore an attempt has been made to approximate these variations analytically. These calculated values could then be used to approach a static water level. The basic ground water theory was considered for confined and unconfined aquifers. The same linear approximation for the equation of the variations of the water level was obtained. This was a diffusion equation. The sinusoidal solution was considered in conjunction with the tides, considered as a sum of sine waves. However this approach was limited to the tides and was quite lengthy. A better method was developed which approximates the earth as a digital filter, fully described by the diffusion equation and its geological and geometrical parameters. An application of this technique showed good time correlation with the actual data and good sensitivity to the ratio of the appropriate parameters. Accordingly, it is proposed that a method incorporating this filter could be used as a tool in the assessment of preliminary wells.
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