Stormwater management

Rain barrels and cisterns

• it must hold a minimum of 200 litres/52 gallons.
• the barrel should be positioned on a flat surface
• the cover and barrel cannot have leaks or be broken in any way
• there must be a screen on the opening of the barrel to prevent contaminants from entering
• the elbow of the eavestrough must be attached so that water is flowing into the barrel
• two or more rain barrels must be connected to downspouts, in sequence or separately
• the overflow spout should not be draining to an paved surface such as a driveway

Tips:

• the barrel/cistern should be disconnected for the winter months to prevent cracking
• raise your barrel a few inches from the ground for better pressure and flow of water
• drain your barrel before the next rain event to make room for more water

Trees

Trees provide many benefits for stormwater management. A tree canopy intercepts rainfall and releases it back into the atmosphere. Root systems promote infiltration and reduce erosion.

For this credit, trees on your property are measured based on their diameter at breast height (DBH). There are two levels for the tree credit.

Level 1: must have the approximate equivalent of five trees on your property. Each one with a trunk the size of a dinner plate or bigger. The total tree diameter must exceed 130 cm (50 inches) to qualify for a 200 litre credit.
Level 2: must have the approximate equivalent 13 large trees on your property.Each one with a trunk the size of a dinner plate or bigger. The total tree diameter must exceed 330 cm (130 inches) to qualify for a 500 litre credit.

Infiltration galleries, soakaway pits, dry wells and French drains

Infiltration galleries have many names including soakaway pits, dry wells and French drains. Their purpose is to allow clean water to soak into the ground and recharge drinking water sources.

They usually take the form of underground pits that are filled with stone or gravel, providing a storage space for water while it absorbs into the ground.

The galleries receive clean rainwater from rooftops, so that groundwater does not become contaminated.

Tips:

• Galleries should be at least five metres away from the house to prevent basement flooding
• there should be nothing blocking the flow into the pit or chamber
• rainwater should be routed from eavestroughs into the gallery

• eavestroughs should have gutter guards to prevent debris from plugging the gallery

Permeable pavers

Permeable pavers allow stormwater to percolate and filter through the pavement and into the aggregate layers or soil below.

Permeable pavement surfaces are made of nonporous and porous materials and allow water to flow between the gaps. Examples of these materials are:

Nonporous materials:

• paving stones
• interlocking paver

Porous material:

• pervious concrete
• porous asphalt

Permeable pavers reduce runoff and improve water quality by filtering pollutants in the subsurface layers.

Tips:

• the difference between traditional paving stones and permeable pavers is a larger spacing between stones
• permeable pavers use a loose gravel mix containing no sand around and below the pavers
• it must contain at least 0.3m (1 ft) of stone base/subbase beneath the paver stones to store stormwater
• patio stone driveways or other systems that lack spacing between the stones and a loose gravel base beneath do not qualify for stormwater credits

Rain gardens

A rain garden is a shallow depression in the ground filled with well-draining soil and mulch and native plants that soak up rain and reduces runoff to local creeks and rivers.

This credit requires the following:

• a quantifiable volume of water must be held on your property
• water from impervious surfaces such as rooftops must be routed directly to the garden
• water should soak into the soil within 72 hours of a rainfall event

Learn more about building a rain garden at the Reep Green Solutions website.

Visit our rain garden at the Waterloo Service Centre from May to October, Monday to Friday, 8:30 a.m. to 4:30 p.m. The customer service desk at the main entrance will direct you to the garden.

Flood controls

Controls include:

• Rooftop storage: a flat roof designed to collect stormwater during rainfalls through orifice plates. The water drains through the outlets and downspouts to the underground drainage system.
• Parking lot storage: allows water to be collected and stored before it flows into the stormwater system.
• Underground storage: detention storage located underground in tanks or vaults that collects and stores runoff. The water is slowly released into our stormwater system.
• Stormwater management pond: designed to collect runoff to prevent flooding.
• Green roof: consists contains soil and vegetation on the rooftop of a building. The plants act as a sponge, soaking up rain water and preventing runoff.

Pollution controls

The credit received for pollution control is based on the level of treatment.

• Enhanced treatment is considered to provide an 80 percent or higher total suspended solids (TSS) removal rate. Enhanced treatment is eligible for up to 15 percent credit.
• Normal treatment is considered to provide a 70 percent TSS removal rate. Normal treatment is eligible for up to 10 percent credit.
• Basic treatment is considered to provide a 60 percent TSS removal rate. Basic treatment is eligible for up to 5 percent credit.
• Additional credit up to the 15 percent maximum may be awarded for other best management practices implemented on site, such as a salt management plan or paved area sweeping program.

Controls include:

• Bioswales: a vegetated open channel designed to reduce and treat runoff. They are formed similar to ditches and are filled with soil called filter media and vegetation that absorbs the runoff.
• Oil/grit separator: a structure installed underground as a part of the stormwater system. It filters runoff by removing pollutants, sediment and oils from the water.
• Paved area sweeping program: sweeping paved areas on a regular basis to reduce the amount of sediment, debris, and trash from entering the storm sewers.

• Salt management plan: reducing the amount of salt used during the winter season improves water quality. The plan must be certified through the Smart about Salt program.
• Stormwater management pond: a pond designed to collect runoff and it allows sediment in the water to settle removing some of the pollutants before releasing the water into our waterways.
• Vegetated filter strip: a low-angled slope covered in vegetation that is designed to slow runoff from entering our waterways. The vegetation acts as a pre-treatment to slow runoff and remove sediment.

Education programs

• Customer: businesses that offer services to customers that may result in impacting our stormwater system may be eligible for the education credit should they offer educational tools. We require copies of the training material(s) to be submitted for review.
• Employee: companies that have implemented a training or awareness program about stormwater management may be eligible for the education credit. We require copies of the training material(s) to be submitted for review.
• Student: schools or post-secondary institutions that distribute materials in highly visible areas or add stormwater management to their curriculum may be eligible for the education credit. We require copies of the training material(s) to be submitted for review.
• Tenant/landlord: landlords who create and distribute educational materials to their tenants may be eligible for the education credit. We require copies of the training material(s) to be submitted for review.