The Province operates a network of 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.154
The hydrograph above shows the change in ground water level in the observation well (meters below ground level) over time. This observation well is manually monitored each month using a wetted tape.
Observation well No.154 is completed to a depth of 14.9 m in aquifer No. 0297, a confined, sand and gravel aquifer. The aquifer is classified as an IIIB (11) aquifer, which is lightly developed and moderately vulnerable to contamination. Since 1969, the ground water level in the well has ranged from a high of 2.0 m below ground level in August 1972, to a low of 4.7 m below ground level in April 2001. The difference between maximum and minimum ground water levels in any single year ranges from approximately 0.4 (in 1989) to 1.5 (in 1972) meters. The hydrograph shows that ground water levels in this observation well generally follow a regular pattern. Maximum ground water levels occur in August and September, and minimum ground water levels occur in the months of April and May. The water level in this observation well may be affected by nearby irrigation return flow, as the maximum ground water levels in August and September coincide with high seasonal irrigation use. Since 1973, this well has generally shown a declining trend in ground water levels.