The Ground Water Section of Water, Land and Air Protection operates a network of 163 observation wells to provide data on ground water level fluctuations and ground water quality information on developed aquifers in British Columbia. Observation well water levels are monitored using one of four methods: 1) manually with a wetted tape, 2) continuously using Steven's chart recorders, 3) electronically with data loggers or 4) remote monitoring using cellphone technology.
Water level data from observation wells are collected on a monthly basis by field observers and forwarded to Regional Offices. Data are then checked for errors and ommissions and forwarded to the Water and Air Monitoring and Reporting Section for final checking and storage. Water level data are referenced from ground level and the month end water level reading are entered and stored in Excel to produce a month-end hydrograph. The method of measurement and accuracy of each method are given below:
|Method of measurement||Accuracy|
|Wetted Tape Method||+/- 1 mm|
|Steven's Chart Recorder||+/- 1 mm|
|Data Logger||+/- 0.1 %|
Hydrograph Analysis- Observation Well No.117
The hydrograph above shows the change in ground water level in the observation well (meters below ground level) over time. Well water level measured by a Steven's recorder, monitors the ground water fluctuation in this observation well.
Observation well No.117 is completed to a depth of 190.5 m in aquifer number 0111, a confined, sand and gravel aquifer. The aquifer is classified as an IIC (11), which is an aquifer that is moderately developed and has a low vulnerability to contamination. Since 1971, the ground water level in the well has ranged from a high of 15.5 m below ground level in March 1973, to a low of 17.6 m below ground level in August 1992. The hydrograph shows that ground water levels in this well generally follow a regular pattern. This well may be affected by nearby pumping over the irrigation season beginning in spring. The ground water level recovers during late fall when irrigation ceases, hence rising ground water level in late fall through winter. The difference between maximum and minimum ground water levels in any single year ranges from approximately 0.1 (in 1976) to 1.5 (in 1998) metres.