Declining quality of water detected in reservoirs below Fraser Valley, expert says

How much water is beneath our feet?

• Groundwater exists almost everywhere underground.  Water is found in soil, rock fractures, faults and joints.  The level below which all of these spaces are entirely filled with water is called the water table.  This is also the level to which water will rise in a shallow well.

• An aquifer is a geological formation of permeable rock or loose material that can be developed to yield useful quantities of water.  Aquifers range in size from a few hectares to thousands of square kilometres.  They can be a few metres thick or hundreds of metres thick 
• Abbotsford-Sumas Aquifer

• . 

• Confined aquifers are located beneath a layer of impermeable materials, so they are more susceptible to declines in water volumes. 

• Unconfined aquifers - such as the Abbotsford aquifer - rise up as far as the water table.  They are easier to recharge, but more susceptible to contamination because they aren't protected by clays or other impermeable layers.

Is B.C.'s groundwater contaminated?

Ten of these problem aquifers are in the Fraser Valley, where the public health guidelines for one or more water contaminant were exceeded at one or more wells. 

Nitrate levels exceed guidelines in nine of the 17 aquifers, likely because of agricultural fertilizer, manure and/or septic fields.

Most of the information about aquifers is collected in areas with large populations.   Little is known about groundwater quality outside these areas.

Source:  Groundwater in B.C., environment, lands and parks ministry, 1997.