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mLine 38:
Line 38: − <h3>Design for Maintenance </h3>+ Line 49:
Line 49: − <em>RWH systems producing higher quality water will have additional maintenance requirements. These will depend on the the treatment technologies being used.</em>+ − + − <h3>Catchments</h3>+ − <h3>Cisterns</h3>+ − <h3>Plumbing and Regulation </h3>+
→Design
#All pipework, pumps, filters and the cistern are protected from freezing during the winter
#All pipework, pumps, filters and the cistern are protected from freezing during the winter
The first option may be suitable for systems optimized for exterior irrigation only. But regulatory authorities may not permit the use of such seasonal systems as part of a storm water control strategy. Year round systems can be protected from freezing by locating the pipes, pumps and cistern indoors and/or below the frost penetration depth[http://www.raqsb.mto.gov.on.ca/techpubs/ops.nsf/0/ee1f1756eacc00e18525808200628fbf/$FILE/OPSD3090.101%20Rev%231%20Nov2010.pdf].
The first option may be suitable for systems optimized for exterior irrigation only. But regulatory authorities may not permit the use of such seasonal systems as part of a storm water control strategy. Year round systems can be protected from freezing by locating the pipes, pumps and cistern indoors and/or below the frost penetration depth[http://www.raqsb.mto.gov.on.ca/techpubs/ops.nsf/0/ee1f1756eacc00e18525808200628fbf/$FILE/OPSD3090.101%20Rev%231%20Nov2010.pdf].
===Design for Maintenance===
Detailed inspection and maintenance advice can be found in [http://www.sustainabletechnologies.ca/wp/wp-content/uploads/2016/08/LID-IM-Guide-7.7-Rainwater-Cisterns.pdf Sustainable Technologies' LID I&M guide].
Detailed inspection and maintenance advice can be found in [http://www.sustainabletechnologies.ca/wp/wp-content/uploads/2016/08/LID-IM-Guide-7.7-Rainwater-Cisterns.pdf Sustainable Technologies' LID I&M guide].
The two primary operational concerns for RWH systems are:
The two primary operational concerns for RWH systems are:
*Can the leaf screens accessed from the roof? Or from a maintenance room?
*Can the leaf screens accessed from the roof? Or from a maintenance room?
*Will the cistern require entry for inspection in the future? How will this be accessed?
*Will the cistern require entry for inspection in the future? How will this be accessed?
''RWH systems producing higher quality water will have additional maintenance requirements. These will depend on the the treatment technologies being used.''
==Design==
==Design==
[[File:RAINWATER HARVESTING TANK 550x550.jpg|thumb|Large cistern being installed underground]]
[[File:RAINWATER HARVESTING TANK 550x550.jpg|thumb|Large cistern being installed underground]]
[[File:RWH.gif|thumb|Conceptual diagram of an underground cistern being used for irrigation]]
[[File:RWH.gif|thumb|Conceptual '''gif''' of an underground cistern being used for irrigation]]
[[Rainwater Harvesting: Sizing and Modelling]]
[[Rainwater Harvesting: Sizing and Modelling]]
===Catchments===
Decisions need to be made about the selection and grading of catchments. If one catchment is very large, can it be regraded to drain to two or more outlets? Is it desirable to capture both rooftop water and other stormwater? This will may determine the quality improvements required to use the water. See table below, which illustrates the higher treatment required for storm water (i.e. non-rooftop).
Decisions need to be made about the selection and grading of catchments. If one catchment is very large, can it be regraded to drain to two or more outlets? Is it desirable to capture both rooftop water and other stormwater? This will may determine the quality improvements required to use the water. See table below, which illustrates the higher treatment required for storm water (i.e. non-rooftop).
===Cisterns===
Preformed above-ground tanks are usually constructed from polyethylene or galvanized steel. They are available with storage capacity up to around 50,000 L. Preformed below-ground tanks may be constructed from reinforced fiberglass or concrete. Fiberglass tanks are available up to around 150,000 L. Concrete vaults can be constructed in almost any size. Wooden tanks are less common but are also available and permitted in the regulations.
Preformed above-ground tanks are usually constructed from polyethylene or galvanized steel. They are available with storage capacity up to around 50,000 L. Preformed below-ground tanks may be constructed from reinforced fiberglass or concrete. Fiberglass tanks are available up to around 150,000 L. Concrete vaults can be constructed in almost any size. Wooden tanks are less common but are also available and permitted in the regulations.
As a standing body of freshwater, RWH cisterns present ideal habitat for [[Pests#Mosquitoes|mosquitoes]]. Mosquitoes should be prevented from entering by using a mesh screen on all openings. Larvicides may be added when the water is only to be used for irrigation purposes.
As a standing body of freshwater, RWH cisterns present ideal habitat for [[Pests#Mosquitoes|mosquitoes]]. Mosquitoes should be prevented from entering by using a mesh screen on all openings. Larvicides may be added when the water is only to be used for irrigation purposes.
To prevent algal growth, the cistern must be opaque or otherwise protect the water from light.
To prevent algal growth, the cistern must be opaque or otherwise protect the water from light.
===Plumbing and Regulation===
The current Ontario Building Code requires that rainwater harvesting systems are designed, constructed and installed to conform to good engineering practice. References are made to ASHRAE, ASPE[https://www.aspe.org/content/arcsaaspeansi-63-2013-rainwater-catchment-systems-electronic-download] and CSA [http://shop.csa.ca/en/canada/plumbing-products-and-materials/cancsa-b1281-06b1282-06-r2016/invt/27024892006] guides for plumbing detailing.
The current Ontario Building Code requires that rainwater harvesting systems are designed, constructed and installed to conform to good engineering practice. References are made to ASHRAE, ASPE[https://www.aspe.org/content/arcsaaspeansi-63-2013-rainwater-catchment-systems-electronic-download] and CSA [http://shop.csa.ca/en/canada/plumbing-products-and-materials/cancsa-b1281-06b1282-06-r2016/invt/27024892006] guides for plumbing detailing.
These guides focus on ensuring that the rainwater does not contaminate or become mistaken for the municipal drinking water supply. Similarly, rainwater must be prevented from becoming contaminated from the sewer. In both cases, an air gap or a back-flow preventer is required.
These guides focus on ensuring that the rainwater does not contaminate or become mistaken for the municipal drinking water supply. Similarly, rainwater must be prevented from becoming contaminated from the sewer. In both cases, an air gap or a back-flow preventer is required.