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 %|
The hydrograph above shows the change in ground water level in the observation well (m below ground level) over time.
Observation well 100
is completed to a depth of 18.9 m in the Osoyoos West (0193) aquifer, a sand
and gravel aquifer. The aquifer is classified as a IIA(16) aquifer, which
is a moderately developed, highly vulnerable aquifer. Since 1969, the ground water
level in the well has ranged from a high of 2.4 m below ground level in September
1993, to a low of 5.3 m below ground level in December 1969. The difference
between maximum and minimum ground water levels in one season ranges from approximately
1.0 to 2.5 metres. Since 1975, this hydrograph shows a relatively regular
pattern likely reflecting recharge from irrigation return flows. The hydrograph
shows an increase of ground water at the start of the irrigation season, peaking
in September and October, and declining as irrigation recharge ceases. Minimum
ground water levels occur in April and May. Some erratic behaviour is seen
in some years, which may be due to pumping interference from surrounding wells.
The observation well may also respond to Osoyoos Lake level fluctuations.