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.107
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 each month using a wetted tape.
Observation well No.107 is completed to a depth of 9.8 m in the Osoyoos West unconfined, sand and gravel aquifer No. 0193. The aquifer is classified as an IIA (16) aquifer, which is a moderately developed, highly vulnerable aquifer to contamination. Since 1969, the ground water level in the well has ranged from a high of 1.6 m below ground level in September 1969, to a low of 4.8 m below ground level in January 1972. The difference between maximum and minimum ground water levels in any single year ranges from approximately 1.2 (in 1978) to 3.0 (in 1972) metres. The hydrograph shows ground water levels in this well generally follow a regular pattern, due likely to annual snowmelt and recharge from irrigation return flow. The hydrograph shows an increase of ground water at the start of the irrigation season, reaching maximum levels in August and September, and declines as irrigation recharge ceases to minimum levels in March, April and May.
This observation well is located on the edge of a runoff channel, caused by irrigation from orchards located above the well; therefore, ground water levels may be affected by this runoff recharge from the orchards. Pumping interference of a nearby pump house may also affect water level fluctuations experienced by the well. The observation well may also be responding to lake level fluctuations, as the well is located 330 m from Osoyoos Lake.