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→Water Quality
Roof catchment area can be estimated using one of many online digital maps. e.g. Distance can be measured on Google maps by right clicking on the desired start point. <br>
Roof catchment area can be estimated using one of many online digital maps. e.g. Distance can be measured on Google maps by right clicking on the desired start point. <br>
1 mm of rain landing on 1 m<sup>2</sup> of roof top produces 1 litre of water to store. <br> So a 5 mm storm on a 75 m<sup>2</sup> roof would require 375 L of storage volume. <br>
1 mm of rain landing on 1 m<sup>2</sup> of roof top produces 1 litre of water to store. <br> So a 5 mm storm on a 75 m<sup>2</sup> roof would require 375 L of storage volume. <br>
Rain barrels or cisterns are readily available in pre-formed plastic up to around 500L. <br>
Rain barrels are readily available in pre-formed plastic in a variety of sizes, ranging from 150 to 200L (typical) up to 500L. <br>
Alternatives include:
Alternatives include:
*modular systems to increase total storage capacity,
*modular systems to increase total storage capacity,
*slim designs to fit small spaces,
*slim designs to fit small spaces,
*aesthetic designs for high profile locations,
*aesthetic designs for high profile locations,
Many people choose to reuse or recycle a container as a rain barrel or cistern. Re-purposed containers should be screened to prevent [[Wildlife#Mosquitoes|mosquitoes]] from breeding, and should be opaque to prevent algae from growing.
Many people choose to reuse or recycle a container as a rain barrel or cistern. Re-purposed containers should be screened to prevent [[Wildlife#Mosquitoes|mosquitoes]] from breeding, and should be opaque to prevent algae from growing.
==Performance==
==Performance==
{{:lit review}}
===Water Quantity===
===Water Quantity===
The use of rain barrels (190L) across a watershed of 100 residential units has been modelled for a number of U.S. cities[http://onlinelibrary.wiley.com/doi/10.1111/jawr.12038/abstract]. In Philadelphia and Milwaukee (reflecting the most similar climates to Southern Ontario) the use of rain barrels for irrigation only, provided an annual stormwater reduction of less than 2%.
The effectiveness of rain barrels depends heavily on whether the homeowner will utilize the stored water. The use of rain barrels (190L) across a watershed of 100 residential units has been modelled for a number of U.S. cities[http://onlinelibrary.wiley.com/doi/10.1111/jawr.12038/abstract]. In Philadelphia and Milwaukee (reflecting the most similar climates to Southern Ontario) the use of rain barrels for irrigation only, provided an annual stormwater reduction of less than 2%.
===Water Quality===
===Water Quality===
There is a draft of [https://www.iccsafe.org/wp-content/uploads/110116-Draft-CSA_ICC-B805-Rainwater-Harvesting.pdf CSA B805 draft] currently under review. The scope of the document includes single family dwellings. But the guide is still under review and may not account for rain barrel systems when officially published.
There is a draft of [https://www.iccsafe.org/wp-content/uploads/110116-Draft-CSA_ICC-B805-Rainwater-Harvesting.pdf CSA B805 draft] currently under review. The scope of the document includes single family dwellings. But the guide is still under review and may not account for rain barrel systems when officially published.
(comments made in reference to draft v. 2, on 1st June 2017).
(comments made in reference to draft v. 2, on 1st June 2017).
Research in warm climates (Texas and Greece) has demonstrated that first flush diverters improve the chemical characteristics of the harvested rainwater[http://www.sciencedirect.com/science/article/pii/S0043135410008535][http://www.sciencedirect.com/science/article/pii/S0022169412006993]. However, the use of diverters does not prevent the development of pathogens in stored water.
Research in warm climates (Texas and Greece) has demonstrated that first flush diverters improve the chemical characteristics of the harvested rainwater[http://www.sciencedirect.com/science/article/pii/S0043135410008535][http://www.sciencedirect.com/science/article/pii/S0022169412006993]. However, the use of diverters does not prevent the development of pathogens in stored water. Rain barrels are not typically accepted to provide any quantifiable water quality treatment beyond that achieved through runoff volume and pollutant load reduction.
==Costs==
==Costs==