Alberta groundwater observation-well network

Groundwater level fluctuations are the result of a number of natural processes affecting addition and subtraction of water to and from the saturated zone. Within the saturated zone itself, intrinsic hydraulic processes are continuously active. There is a complex relationship between such processes, and identification of the specific effect of one process on water levels is very difficult if not impossible. Major natural processes affecting groundwater levels include recharge and discharge of water to and from the saturated zone respectively, and movement of water in hydrodynamic flow systems. Other important processes affecting levels are atmospheric pressure changes, transpiration, aquifer compression and aquifer dilatation.

In addition to natural processes, the activities of man affect groundwater levels. The primary activity is the withdrawal of groundwater by means of wells. Other major activities include artificial recharge, irrigation, land clearing, secondary recovery of oil, construction of reservoirs and mining.

In this report, these natural processes and major activities of man that affect groundwater levels are discussed, and illustrative examples of fluctuations are selected from hydrographs for 64 observation wells located throughout Alberta. Examples of typical hydrographs for annual water level fluctuations unaffected by man's activities are also presented.

Examination of these hydrographs leads to a general conclusion that groundwater levels in Alberta have remained rather constant 1959, with exceptions in local areas. The exceptions are usually caused by large scale production (withdrawal) of groundwater from wells. Water levels are lowered during production, but recover to normal levels when production ceases. The period required to re-establish preproduction water levels ranges from a few months to many years.