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Landscaping practices, and the choices we make when planning, planting, and tending to our properties, can have notable effects on local drinking water sources, including lakes, rivers, and underground aquifers. This article details the ways in which landscaping and gardening has the power to impact drinking water, both in terms of quality and quantity, and provides suggestions for landscaping strategies that can help to protect our drinking water supplies.

How Can Landscaping Impact Source Water?
Landscaping choices can impact drinking water sources in the following ways:

  • Reduction of surface run-off and flooding: vegetation will intercept and uptake rainwater, reducing the amount of water available to contribute to surface run-off. Run-off from rain events can easily accumulate contaminants as it travels over the ground’s surface, before entering drinking water sources.

  • Filtration of contaminants: plants – especially their roots – are able to intercept & capture contaminants, removing them from the soil matrix before they can enter drinking water sources.

  • Reduction in soil erosion: plant roots protect against erosion, by physically helping to hold soil in place. The displacement of soil that occurs during erosion processes can result in a higher amount of sediment entering local drinking water sources; this soil can also contain chemicals and other drinking water contaminants.

  • Reduction of chemical contamination: replacing pesticides and synthetic fertilizers with chemical-free gardening practices, and natural compost can help to protect drinking water sources from contamination.

  • Protection against over-use: Landscapes that require significant amounts of added irrigation, pulled from the local drinking water supply, can have a detrimental effect on the available quantity of drinking water –  particularly during periods of summer drought. Choosing locally adapted, drought-tolerant plant species can reduce the need for added irrigation. Similarly, rain barrels can be used to capture and store rainwater, to allow for irrigation without depleting drinking water sources.

Seven Intentional landscaping practices for source water protection

This list highlights seven ways to utilize plants, and landscaping strategies, for the purpose of preventing drinking water contamination, and maintaining abundant water supplies:

  1. Choose native plants.
    Native plants are better adapted to the local environment and have a lesser need for added fertilizer in order to flourish. They are also better suited to the local climate conditions, often requiring less irrigation, which can reduce the demand on your drinking water supply. In fact, when possible, opting for drought-tolerant, native plants, will further decrease the need for added irrigation, and protect your drinking water quantity.
  2. Choose a diverse mix of plant types.
    A mix of trees, shrubs, and ground cover species will introduce root systems into multiple layers of the soil. This aids in reducing erosion, as well as the ability of your garden to capture contaminants throughout the soil matrix. A diverse garden is also more resilient in the face of extreme weather or damaging events, increasing the likelihood that it will persist year after year.
  1. Plant cover crops.
    Bare ground does very little to mitigate or reduce surface run-off and is highly susceptible to erosion – both of which provide contaminants a pathway into drinking water sources. Cover crops, such as native clover, can help to reduce both run-off and erosion, in order to protect water quality.
  1. Leave, or restore, natural buffers around water sources.
    Leaving an untouched, natural, grassy, or vegetated buffer around your well can reduce the risk of well damage by lawn mowers and other equipment, as well as provide an added line of defence against contaminants, as these plants will help to intercept and capture pollutants before they can enter the well supply. Leaving or restoring natural, vegetative buffers along shorelines provides similar benefits, especially when drinking water is obtained from surface water (e.g., via surface water intakes). For properties adjacent to agricultural lands, planting a row, or rows of trees (called “windrows”) around the property’s perimeter can further help to protect the local water source against pesticide drift.
  1. Switch to chemical-free gardening practices.
    Replace synthetic fertilizers and pesticides with non-chemical alternatives. For example, household food scraps can be saved to create nutrient-rich compost, that will support plant health and growth, while manual weeding of invasive plants is also just one way (of many) to manage undesirable weeds.
  1. Install a rain barrel.
    Installing a rain barrel under a downspout, to capture and store rainwater, will provide water for garden irrigation without impacting drinking water quantity.
  1. Construct an artesian well or a rain garden.
    Artesian wells are dry, dug wells, filled with stones, for the purpose of collecting and storing rainwater and surface-run-off; their presence can help to reduce flooding and the quantity of run-off, thereby helping to protect again drinking water contamination. Rain gardens are gardens planted in shallow pits (natural or constructed); these concave gardens are also intended to collect rainwater and surface run-off and are typically placed along the usual path of surface water flow. The presence of plants in these pits is particularly effective at controlling the absorption of water into the soil, as well as intercepting and capturing contaminants.

If looking to hire the assistance of a landscaper this summer, professionals and business that place an emphasis on environmental protection or climate resilience through their work, are most likely to make landscaping decisions that best align with the protection of your drinking water sources, along with that of the natural environment.  

Helpful Resources:

  1. Utilities Kingston: Water Conservation Garden
  2. Ontario Clean Water Agency: Water-Efficient Landscaping
  3. Toronto Region Conservation Authority: Building a Rain Garden
  4. Government of Ontario: Best Practices for Source Water Protection
  5. Conservation Ontario: Source Water Protection
  6. Conservation Ontario: What Landowners Can Do to Protect Water (Resource)
  7. Conservation Ontario: Run-off, Erosion Protection and Additional Best Management Practices (Resource)