Vulnerable Areas

Updated on July 03, 2026

Vulnerable Water Areas

Vulnerable Aquifers 

Vulnerable aquifers are aquifers that are more susceptible to contamination from activities on the surface, such as pesticide use or improper disposal/ storage of hazardous waste. 

In the RDN, we have several communities and neighbourhoods built over top of vulnerable aquifers. These aquifers also provide drinking water to people on private wells. Residents of these areas need to be aware that their actions on the surface have a very direct impact on the groundwater beneath them. 

Vulnerable aquifers are near the ground surface, have a greater net recharge (lots of water flows into the aquifer), and are covered by a permeable type of soil such as sand and gravel. 

What Makes Aquifers Vulnerable?  

  • Depth of Water: Aquifers that are near the ground surface have less of a barrier between the activities above ground and the water below ground. Shallow soils/rock above the aquifer are limited in their capacity to naturally filter out surface contaminants. 
  • Amount of Water that Enters the Ground: Greater recharge, or flow of water into the aquifer, makes it more likely that contaminants will hitch a ride. Topography (slope of the land) influences this. Flatter ground means higher infiltration rate. 
  • Type of Soil/Substrate Overlaying the Aquifer: Thin, sandy soils are an ineffective barrier to contaminants. Aquifers that have a layer of clay above them are ‘confined’: the impermeable clay layer blocks surface contaminants from reaching the water table. Unconfined sand and gravel aquifers are more vulnerable to contamination. 

How They Are Contaminated 

Rain and snowmelt re-charge or re-fill the aquifer by seeping down through the soil and becoming groundwater. Water is filtered and cleaned naturally as it flows through the soil and sediments. Of course, deeper soil/sediment provides better filtration. Among other factors, how quickly water gets into the ground influences how vulnerable the groundwater is to contamination. 

Contaminants on the ground surface like oil, pesticides, fertilizer, pet/animal waste, paint, or antifreeze can be picked up by the rainwater as it runs off paved surfaces, lawns and fields. This is how water can become polluted on its journey into the aquifer. 

Household Tips for Protecting Aquifers 

  • Store and dispose of hazardous waster properly. Store hazardous materials safely indoors and away from water sources such as wells. Take unused or expired paints, cleaners, pesticides and prescription pills to the local hazardous waste facility. 
  • Maintain your septic. In vulnerable areas, water drains rapidly through the soil. If your septic isn’t working right, raw sewage can percolate very quickly into the groundwater below. Regular inspections and pump-outs when due go a long way to protecting water quality & saving money. 
  • Use non-toxic cleaning products and organic lawn care. Check the labels of your cleaners to ensure or make your own with a vinegar base. Cultivate health soil with compost; organic methods are cheaper and safer.  
  • Take care when refueling gas tanks or changing oil. Use a drop-cloth to catch spills and dispose of waste oil at proper facility. A single drop of oil can contaminate a million drops of water. 
  • Clean up pet waste and manage livestock manure. These wastes contain bacteria that can pollute waterways.  
  • Protect Your Water Well. Make sure your well is properly capped and has a surface seal so that no polluted surface run-off can enter the well and get into the groundwater. Do not use a pumphouse to store hazardous materials.  
  • Conserve water. Lower water level in a source can mean contaminants are more concentrated.  

Resources 

Riparian Ecosystems 

Riparian Ecosystems are the areas alongside a stream or river. They protect water quality while providing habitat. Trees, shrubs and grasses along a river act to stabilize the riverbank and filter any water before it reaches the stream. 

If vegetation in this area is grazed or removed, there are no plant roots to hold the soil in place and the banks are prone to erosion. When the stream banks erode, soil and sediment enter the water, making it cloudy and smothering fish habitat. 

Vegetation along stream banks slows the rush of water into the river when it rains and filters sediments and contaminants in the soil before they enter the waterway. If you have a stream on your property, keep its banks vegetated. 

Explore these resources for helping preserve Riparian Ecosystems: