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.115
The hydrograph above
shows the change in ground water level in the observation well (meters below
ground level) over time. From 1973 to 1996, the well water level was measured
by a Steven's recorder, which monitors ground water level fluctuations in the
observation well. In September 1996, the recorder was removed and replaced
by a digital data logger, which monitors ground water level fluctuations and
sends the data via satellite.
Observation well No.115 is completed to a depth of 21.9 m in an undelineated, bedrock aquifer. This observation well was drilled to gain information on the relationship between ground water recharge and snowmelt runoff at higher elevations. Since 1973, the ground water level in the well has ranged from a high of 0.9 m below ground level in May 1990, to a low of 7.9 m below ground level in April 2001. The hydrograph shows that the ground water levels in this well follow a regular seasonal pattern. Maximum ground water levels occur in May and June, corresponding to ground water recharge from snowmelt, and minimum ground water levels occur in the months of March and April. The difference between maximum and minimum ground water levels in any single year ranges from approximately 4.0 (in 1999) to 6.2 (in 1995) metres. From 1999 to 2001, the well had mechanical problems where the float became intermittently stuck and therefore could not accurately record all fluctuations. In October 2001, a 5 inch float was replaced with a 4 inch float in the well casing.