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Line 7: − + + − + − * Costs for conveyance piping are not included in the model design for indoor tanks because conveyance would be needed even without RWH. − * The cost for decommissioning an outdoor above-ground plastic tank for [[#Cold climate considerations#Winter Management|the winter]] is not included. − * The tool assumes that only one trench is needed for all piping, including conveyance, service and top-up piping.
Rainwater Harvesting & Cisterns: Life Cycle Costs (view source)
Revision as of 19:28, 10 January 2023
, 1 year ago→Design Assumptions
==Design Assumptions==
==Design Assumptions==
[[Rainwater harvesting|Rainwater harvesting (RWH)]] is ideal for sites that cannot infiltrate water (e.g. contaminated soils, WHPAs, IPZs, etc.), zero-lot-line developments, large gardens and landscaped areas. Components include: catchment area (e.g. rooftop), [[Pretreatment| pretreatment]] filter to remove coarse debris, cistern storage, and a connecting pipe network. Additional components include pumps to lift water to higher elevations, additional water filtration and treatment. <br>
[[Rainwater harvesting|Rainwater harvesting (RWH)]] is ideal for sites that cannot infiltrate water (e.g. contaminated soils, WHPAs, IPZs, etc.), zero-lot-line developments, large gardens and landscaped areas. Components include: catchment area (e.g. rooftop), pretreatment filter to remove coarse debris, cistern storage, and a connecting pipe network. Additional components include pumps to lift water to higher elevations, additional water filtration and treatment. <br>
Design and operation and maintenance program assumptions used to generate the cost estimate are based on tool default values and the following STEP recommendations:
Design and operation and maintenance program assumptions used to generate the cost estimate are based on tool default values and the following STEP recommendations:
* Total daily water use of 2,000 L per day (tool default).
* Total daily water use of 2,000 L per day (tool default).
* User specified storage tank capacity of 50,000 L.
* User specified storage tank capacity of 50,000 L.
* Two (2) German-style in-line filters and precast concrete containment structures are included to provide pretreatment of roof runoff.
* Operation and maintenance (O&M) cost estimates assume annual inspections and cistern pump tests, removal of trash and debris from rooftop and pretreatment filter four times a year, and cleaning of cistern and replacement of pump and pressure tank every five years. Verification inspections are included every 5 years to confirm adequate maintenance.
* Operation and maintenance (O&M) cost estimates assume annual inspections and cistern pump tests, removal of trash and debris from rooftop and pretreatment filter four times a year, and cleaning of cistern and replacement of pump and pressure tank every five years. Verification inspections are included every 5 years to confirm adequate maintenance.
===Notes===
===Notes===
* Overflow was not costed as it would be needed even if the RWH system was not constructed.
*
* The tool calculates costs for new (greenfield) development contexts and includes costs for contractor overhead and profit, material, delivery, labour, equipment (rental, operating and operator costs), hauling and disposal.
* The tool calculates costs for new (greenfield) development contexts and includes costs for contractor overhead and profit, material, delivery, labour, equipment (rental, operating and operator costs), hauling and disposal.
** Land value and equipment mobilization and demobilization costs are not included, assuming BMP construction is part of overall development site construction.
** Land value and equipment mobilization and demobilization costs are not included, assuming BMP construction is part of overall development site construction.