Rain garden

Parts of a model rain garden

Rockery

Depression

Plants (native shrubs/perennials and flowers)

Filter bed

Bern

What is the best definition for a raingarden?

Sunken bed that collects stormwater runoff

Functions of plants and rockery

Channels water from the storm drains to flow into the filter bed

Functions of filter bed

Filter stormwater runoff

Function of depression

To hold the stormwater runoff

What is the function of the bern?

To direct water toward specific areas within the rain garden for optimal infiltration

OR

Helps to create separate planting zones within the garden itself

How does raingarden work?

• Runoff collected from paved and other hard surfaces are directed into the garden

• Runoff is first filtered through the plants at the surface, and then percolates through a filter media where fine particles are removed and soluble nutrients are taken up by the plants and soil microbes

Rain gardens are (dryness)

dry most of the time

Holds water only during and after rainfall

Drain water within 48 hours → prevent breeding of mosquitoes

Benefits of rain gardens

- Conserves water:

- Improves water quality:

- Reduces flooding and erosion:

- Supports local wildlife and biodiversity:

- Preserves native vegetation:

- Provides localized stormwater and flood control:

- Attracts beneficial birds, butterflies, and insects:

Elab conserves water

Rain gardens help the community by reducing the need for irrigation, saving water resources.

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This not only benefits the environment but also helps lower water bills for residents and promotes a sustainable water use culture within the community.

Elab improves water quality

By filtering pollutants before they enter local water systems, rain gardens protect the quality of the community’s water supply.

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This ensures cleaner rivers, lakes, and drinking water for everyone in the area.

Elab on helps reduce flooding and soil erosion

Rain gardens help protect neighbourhoods by managing stormwater runoff, reducing the likelihood of local flooding, and preventing erosion.

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This keeps streets, homes, and public spaces safer, contributing to a more resilient community infrastructure.

Supports local wildlife and biodiversity:

• Rain gardens create green spaces that support local wildlife, enriching the community by providing residents with opportunities to engage with nature.

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• This fosters a sense of pride and well-being, while also preserving native species and biodiversity.

elab Preserves native vegetation

By incorporating native plants into rain gardens, communities can protect and promote local biodiversity.

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This not only supports the ecosystem but also connects residents to the area's natural heritage.

- Provides localized stormwater and flood control:

Rain gardens help reduce stormwater runoff by capturing and slowly releasing it into the ground. This minimizes the risk of flooding in neighbourhoods and relieves pressure on the local drainage systems, making the community more resilient to heavy rains.

Attracts beneficial birds, butterflies, and insects:

The plants in rain gardens provide habitats for pollinators and other beneficial species, enhancing the beauty and ecological health of the community.

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These natural spaces can foster a sense of pride and connection among residents.

What do the plants do?

Maintain porosity of the soil and take up nutrients from the runoff (filter)

Soil particles, some types

These are ‘filter media’

Burnt soil (clay-based)

Sand

Slit

Gravel

Soil properties and what affects it

Porosity (spaces between particles)

Permeability (water drainage)

Holding capacity (water retention)

Affected by the size and texture of particles

Pores, what is it

Space between soil particles

• can be filled with water/air

Porous soil has?

A lot of pores

How does pore size affect water retention?

Larger pores → allow water and nutrients to move quickly

Smaller pores - tightly hold onto water and nutrients

What is permeability

Rate at which a fluid flows through a porous substance under given conditions

What is holding capacity

Ability of the soil to stop water and nutrients from seeping out

Permeability, holding capacity and porosity of sand, gravel, silt and clay, increasing order

Permeability

Clay, silt, sand, gravel

Porosity

Clay, silt, sand, gravel

Holding capacity

Gravel, sand, silt, clay

How does rain gardens prevent eutrophication?

Rain gardens can be set up near ponds or lakes

The rainwater runoff will flow into the rain gardens

The nutrients in the runoff will be absorbed by the plants of the rain garden

This reduces the amount of nutrients released into ponds or lakes, preventing the growth of excessive algae.