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.153
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 every month using a wetted tape.
Observation well no. 153 is completed to a depth of 7.0 m in aquifer no. 297, 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 0.6 m below ground level in August 1997, to a low of 2.9 m below ground level in May 1998. The difference between maximum and minimum ground water levels in any single year generally ranges from approximately 0.01 (1973) to 1.7 (1998) meters. Ground water level fluctuations in 1998 and 2001 were more significant (up to 1.7m fluctuations in 1998). The cause of the large fluctuations in 1998 to 2001 is currently not known but could possibly be due to well pumping nearby.
The hydrograph shows that ground water levels in this observation well generally follow a regular pattern. Maximum ground water levels occur in July and August and minimum ground water levels occur in the months of April and May. Ground water levels for this observation well may be affected by pumping interference, causing complex peaks and lows.