Environmental Trends 2002

Ground Water

Percentage of Observation Wells that Show Declining Water Levels Due Primarily to Human Activity

SOURCE: Ministry of Water, Land and Air Protection, 2001. NOTES: Number of observation wells with suitable long-term trend data increased from 31 to 163 over a 35-year period. Due to missing data, loss of observers, etc., only 139 sites were suitable for assessing trends for the period 1995-2000.

Status and trends in groundwater supply

• This indicator was revised as a result of comments received from the last edition of Environmental Trends. It now accounts for natural climatic variation by reporting on only those wells that show declining water levels due primarily to human activities such as nearby groundwater pumping.

• The percentage of observation wells with declining water levels due primarily to human activities was 14% in 1995-2000 (20 of 139 wells monitored).

• The data show that groundwater levels are not declining across the province, but rather in local areas where groundwater withdrawal and urban development has been intensive. Of 20 observation wells showing water level decline in 1995-2000, 5 are on the Lower Mainland, 3 are in the Okanagan and 7 are along the southern east coast of Vancouver Island and on the Gulf Islands.

• The decrease in the percentage of observation wells showing declining water levels due to human impacts since 1990 is believed to reflect the changing spatial distribution of observation wells and changes in groundwater demand.

• Industry (e.g., manufacturing, mining and aquaculture) is the largest user of groundwater in British Columbia (approximately 55% by volume) followed by agriculture (approximately 20%) and municipalities (approximately 20%).

Why is it important?

• In some areas where available surface water supplies are already fully allocated, are too costly to develop, or are of marginal quality, groundwater is the only viable and cost-effective source of water supply.

What is being done?

• Phase 1 of the Ground Water Protection Regulation was announced on July 7, 2004.

• Enhancements are being made to groundwater inventory activities, including automating data collection, establishing additional observation wells in new groundwater areas and reporting water level data on the Internet.

• Development of well and aquifer protection plans at the community level, including measures to protect the quantity of groundwater supplies, are being encouraged in cooperation with local government and water purveyors.

For detailed information, including graph data, see In-Depth report [pdf].