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 071
The hydrograph above shows the change in ground water level in the observation well (m below ground level) over time. This observation well was monitored continuously using a Stevens ground water level chart recorder until 1992, when it was then converted to manual wetted tape measurement recordings.
Observation well 071
is completed in an unmapped, sand and gravel aquifer to a depth of 16.8 m. Since
1976, the ground water level in the well has ranged from a high of 2.5 m below
ground level in March 1999, to a low of 4.5 m below ground level in November
1994. The hydrograph shows that ground water levels follow a complex seasonal
pattern. Complex peaks may be due to the draw down effect of pumping by neighbouring
de-watering wells. Maximum ground water levels occur most often during February,
March and April and minimum ground water levels occur most often in September,
October and November. The difference between maximum and minimum ground water
levels in one season ranges from approximately 0.2 to 0.7 metres.