The Ground Water Section of the Ministry 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 075
The hydrograph above shows the change in ground water level in the observation well (m below ground level) over time. This observation well is monitored manually by taking ground water level measurements using a wetted tape.
Observation well 075 is completed to a depth of 28.0 m in aquifer 0259, an unconfined, sand and gravel aquifer. The aquifer is classified as an IIA (14) aquifer - moderately used and highly vulnerable to contamination from land surface. Since 1963, the ground water level in the well has ranged from a high of 0.6 m below ground level in June 1968, to a low of 4.8 m below ground level in January 1967. Records for this observation well appear to reflect effects of pumping and precipitation recharge. The hydrograph shows that ground water levels follow a seasonal pattern, with maximum ground water levels occurring in May and June, corresponding to annual snowmelt and minimum ground water levels occurring during the September to November period. A second minor peak in ground water levels occurs in November and December, possibly reflecting recharge from irrigation return flow. The difference between maximum and minimum ground water levels in one season ranges from approximately 0.5 to 3.5 metres.