Aquifer Awareness

Here in Shoreacres, we rely on Aquifer 514 for our groundwater supply.

Groundwater is water that infiltrates Earth’s surface.  It fills the space between particles, gravels, and rock fractures in the Earth’s subsurface for storage and transport.

Aquifer 514 below Shoreacres is partially confined.

Aquifers are permeable layers of rock that store and transport water.

• Confined aquifers are saturated units contained by two confining layers.
  • Saturated: a zone where available air space is completely filled with water.
  • Confining layers (aquitards) are not permeable or have relatively very low permeability. Solid rock is an example of a confining layer, as is silt or clay.
  • These aquifers are very slow to recharge.
• Unconfined aquifers do not have confining layers and are unsaturated.
  • Unsaturated: a zone where the available air space is not completely filled with water.
  • These aquifers are more vulnerable to contamination.
• Partially confined aquifers are confined aquifers with windows where there is no confining layer.
  • These aquifers are also vulnerable to contamination.

Aquifer 514 is a glacio-fluvial sand and gravel aquifer.

• The type of our aquifer is:
  • Glaciofluvial sand and gravel aquifers at surface, as well as sand and gravel aquifers occurring underneath till or glaciolacustrine deposits.
    • Glaciofluvial means having to do with glacial rivers.
    • Glaciolacustrine means having to do with glacial lakes.
• The subtype is:
  • Confined sand and gravel aquifers underneath till, in-between till layers, or underlying glaciolacustrine deposits.
    • Till is a rock load deposited by glaciers.

The aquifer type can help determine the amount of water that can be stored and transported in the subsurface. The aquifer type will have characteristic porosity and permeability.

• Porosity is the amount of space between particles in the subsurface. Round particles have greater porosity than angular ones.
  • Particles of the same size have a higher porosity.
  • Smaller particles have more porosity than larger ones.
  • Porosity is made up of both effective porosity (interconnected porosity) and isolated pore space.
    • Effective porosity is measured by:
      • Specific retention: the amount of water that a unit can retain; and
      • Specific yield: the amount of water that is available for pumping.
• Permeability describes the water’s ability to move through pore spaces in the subsurface. Larger particles give higher permeability.

Since Shoreacres has a sand and gravel aquifer, porosity would be moderate to high and permeability high.

Aquifer 514 below Shoreacres is recharged by precipitation.

• Aquifers are recharged by the water cycle.
  • The water cycle “starts” when water is evaporated from the ocean or a surface water body into the atmosphere.
  • This water condenses into clouds and later falls as precipitation (rain or snow etc.).
    • Snow can accumulate and either be stored as ice caps or glaciers for thousands of years or as snowpack which melts and flows overland as snowmelt in the following spring.
  • Most precipitation falls back into the oceans or onto land.
    • Precipitation onto land contributes to surface water bodies (lakes), streamflow (rivers, streams), and if infiltrated, groundwater flow.
    • As water moves across Earth’s surface, much of it soaks into the ground as infiltration, replenishing groundwater flow.
  • Eventually, groundwater and surface water will return to the ocean where it can “begin” another cycle.

The recharge rate for the Aquifer 514 is also related to the overlying geologic material. The groundwater flow below Shoreacres is likely to the west.

• The surficial soils of Shoreacres are made up of mineral particles derived from the glaciofluvial aquifer material .
• Underlying the soil is a variety of glaciofluvial units comprised of clay, silt, sand, and gravel.
• The soils in Shoreacres drain readily to rapidly due to a low to intermediate specific retention.
• Groundwater flow at Shoreacres likely moves towards the west, except for at the western extent where if in contact with the river, it will flow south.
  • In unsaturated zones, water is transported via infiltration or seepage.
  • In saturated zones, water is transported via groundwater flow. Groundwater flow is determined by porosity, permeability, pressure, and slope.

Water levels are lowest in February and highest in the spring as measured in 2019/2020

The water table is where the saturated and unsaturated zones meet.

• The unsaturated zone below Shoreacres is about 22.3m deep. Below this depth, the ground will be saturated.

Aquifer 514 below Shoreacres is moderately developed and moderately vulnerable (Class IIB).

Maintaining the health of our aquifer is important!

The greatest threats to groundwater resources are created by human activity, which is why our collective actions are so important.

• Water quantity can be threatened when aquifer recharge is slower than the rate of withdraw.
• Water quality can be compromised when human activities introduce pollutants to groundwater.

THREE REASONS TO PROTECT OUR AQUIFER!

Community Health: In Shoreacres, we all rely on groundwater found in Aquifer 514. Compromised groundwater quality or quantity would impact our lifestyles. Shoreacres has a moderately-productive aquifer, so water resources must be managed sustainability for future generations to also be water-secure. In terms of water quality, we know that Shoreacres has a vulnerable aquifer. That means we must take care that our actions do not have the potential to contaminate our own water or our neighbour’s water. If our groundwater were contaminated, we would be at risk of illness.

The Environmental Case: Groundwater will eventually interact with the surface environment and surface water. For example, if polluted groundwater were to discharge into a freshwater body or land surface, those contaminants would be introduced and be a potential threat to local plants and animals .  Additionally, groundwater discharge is important for regulating surface water temperature; groundwater is cold, so it cools surface water. This ensures that surface water retains a livable temperature, which is critical to fish survival. Water use should also be managed so it does not threaten water levels or temperatures.

The Business Case: When groundwater is polluted it can be very costly to impossible to “clean up” . It is therefore far more cost-effective to be proactive and preserve aquifer health.

More Online Resources:

Did you know? Aquifer 514 is being monitored by the Living Lakes Canada Groundwater Observation Program! You can…

View the 2020 data summary

View the 2019 data summary

Use the BC real-time data tool and quick-start guide.

Questions or Comments? Submit Here!