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+ | [[File:General information page image.png|right|100px|alt=image]] | ||
+ | [[File:Overview image.png|right|thumb|300 px|alt=This schematic shows Example Stormwater Harvesting and Use System Schematic|<font size=3>Example Stormwater Harvesting and Use System Schematic</font size>]] | ||
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+ | Harvest and reuse is the practice of collecting and/or storing stormwater on site to be used in water applications as needed. Harvest and reuse systems use collected water from various sources, treats them, and then reuses this water on site for different purposes such as irrigation or water features. This practice mitigates the users cost for water, reduces the site's stormwater runoff, and prevents pollution runoff. | ||
+ | |||
+ | Sites containing these systems are not regulated by the EPA but may be regulated by the state through the Safe Drinking Water Act or the Clean Water Act. Water harvest and reuse systems are regulated in Minnesota by Minnesota Rules Section 4714, chapter 17. | ||
+ | |||
+ | Rainwater harvesting is categorized into two types of harvest: | ||
+ | *Surface runoff harvesting | ||
+ | *Rooftop harvesting | ||
+ | |||
+ | Both categories of rainwater harvesting follow the same principles for stormwater reuse. When the rainwater falls onto the site the water is collected through a series of conveyance systems into a storage system, the water is then treated and stored, and the user applies it to their site through a distribution system for the designed purpose. Some designed purposes can be: | ||
+ | *Irrigation systems | ||
+ | *Potable water resources (with treatment) | ||
+ | *Urinal flushing | ||
+ | *Water features | ||
+ | *Vehicle, building, and street cleaning | ||
+ | *Fire suppression systems | ||
+ | |||
+ | Harvest and reuse systems are excellent stormwater treatment practices due to the pollutant removal mechanisms they can be paired with such as vegetative filtering, settling, evaporation, infiltration, transpiration, biological and microbiological uptake, and soil adsorption. Additionally, the pollutants stay on site instead of being flushed downstream. These systems are particularly effective when used for irrigation on C and D soils where traditional infiltration practices are less effective. | ||
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==Green infrastructure and multiple benefits== | ==Green infrastructure and multiple benefits== | ||
+ | {| class="wikitable" style="float:right; margin-left: 10px; width:500px;" | ||
+ | |- | ||
+ | ! Benefit !! Effectiveness !! Notes | ||
+ | |- | ||
+ | | Water quality || <font size=4><center>◕</center></font size> || Primary benefit is retention of sediment and associated pollutants; nutrient cycling in properly functioning wetlands; may export phosphorus if not designed and maintained properly. | ||
+ | |- | ||
+ | | Water quantity/supply || <font size=4><center>◑</center></font size> || Rate control, flooding benefit. | ||
+ | |- | ||
+ | | Energy savings || <font size=4><center>◔</center></font size> || | ||
+ | |- | ||
+ | | Climate resiliency || <font size=4><center>◑</center></font size> || Provides some rate control. Impacts on carbon sequestration are uncertain. | ||
+ | |- | ||
+ | | Air quality || <font size=4><center>◔</center></font size> || | ||
+ | |- | ||
+ | | Habitat improvement || <font size=6><center>●</center></font size> || Use of perennial vegetation and certain media mixes promote invertebrate communities. | ||
+ | |- | ||
+ | | Community livability || <font size=4><center>◕</center></font size> || Aesthetically pleasing and can be incorporated into a wide range of land use settings. | ||
+ | |- | ||
+ | | Health benefits || <font size=4><center>◑</center></font size> || | ||
+ | |- | ||
+ | | Economic savings || <font size=4><center>◕</center></font size> || Generally provide cost savings vs. conventional practices over the life of the practice. | ||
+ | |- | ||
+ | |Macroscale benefits || <font size=4><center>◑</center></font size> || Individual practices are typically microscale, but multiple practices, when incorporated into a landscape design, provide macroscale benefits such as wildlife corridors. | ||
+ | |- | ||
+ | | colspan="3" | Level of benefit: ◯ - none; <font size=5>◔</font size> - small; <font size=5>◑</font size> - moderate; <font size=5>◕</font size> - large; <font size=6>●</font size> - very high | ||
+ | |} | ||
+ | |||
Green infrastructure (GI) encompasses a wide array of practices, including stormwater management. Green stormwater infrastructure (GSI) encompasses a variety of practices primarily designed for managing stormwater runoff but that provide additional benefits such as habitat or aesthetic value. | Green infrastructure (GI) encompasses a wide array of practices, including stormwater management. Green stormwater infrastructure (GSI) encompasses a variety of practices primarily designed for managing stormwater runoff but that provide additional benefits such as habitat or aesthetic value. | ||
Harvest and reuse is the practice of collecting and/or storing stormwater on site to be used in water applications as needed. Harvest and reuse systems use collected water from various sources, treats them, and then reuses this water on site for different purposes such as irrigation or water features. This practice mitigates the users cost for water, reduces the site's stormwater runoff, and prevents pollution runoff.
Sites containing these systems are not regulated by the EPA but may be regulated by the state through the Safe Drinking Water Act or the Clean Water Act. Water harvest and reuse systems are regulated in Minnesota by Minnesota Rules Section 4714, chapter 17.
Rainwater harvesting is categorized into two types of harvest:
Both categories of rainwater harvesting follow the same principles for stormwater reuse. When the rainwater falls onto the site the water is collected through a series of conveyance systems into a storage system, the water is then treated and stored, and the user applies it to their site through a distribution system for the designed purpose. Some designed purposes can be:
Harvest and reuse systems are excellent stormwater treatment practices due to the pollutant removal mechanisms they can be paired with such as vegetative filtering, settling, evaporation, infiltration, transpiration, biological and microbiological uptake, and soil adsorption. Additionally, the pollutants stay on site instead of being flushed downstream. These systems are particularly effective when used for irrigation on C and D soils where traditional infiltration practices are less effective.
Benefit | Effectiveness | Notes |
---|---|---|
Water quality | Primary benefit is retention of sediment and associated pollutants; nutrient cycling in properly functioning wetlands; may export phosphorus if not designed and maintained properly. | |
Water quantity/supply | Rate control, flooding benefit. | |
Energy savings | ||
Climate resiliency | Provides some rate control. Impacts on carbon sequestration are uncertain. | |
Air quality | ||
Habitat improvement | Use of perennial vegetation and certain media mixes promote invertebrate communities. | |
Community livability | Aesthetically pleasing and can be incorporated into a wide range of land use settings. | |
Health benefits | ||
Economic savings | Generally provide cost savings vs. conventional practices over the life of the practice. | |
Macroscale benefits | Individual practices are typically microscale, but multiple practices, when incorporated into a landscape design, provide macroscale benefits such as wildlife corridors. | |
Level of benefit: ◯ - none; ◔ - small; ◑ - moderate; ◕ - large; ● - very high |
Green infrastructure (GI) encompasses a wide array of practices, including stormwater management. Green stormwater infrastructure (GSI) encompasses a variety of practices primarily designed for managing stormwater runoff but that provide additional benefits such as habitat or aesthetic value.
There is no universal definition of GI or GSI (link here for more information). Consequently, the terms are often interchanged, leading to confusion and misinterpretation. GSI practices are designed to function as stormwater practices first (e.g. flood control, treatment of runoff, volume control), but they can provide additional benefits. Though designed for stormwater function, GSI practices, where appropriate, should be designed to deliver multiple benefits (often termed "multiple stacked benefits". For more information on green infrastructure, ecosystem services, and sustainability, link to Multiple benefits of green infrastructure and role of green infrastructure in sustainability and ecosystem services.
Maximizing specific green infrastructure (GI) benefits of constructed areas requires design considerations prior to installation. While site limitations cannot always be overcome, the following recommendations are given to maximize the GI benefit of water harvesting and reuse.
Note: Harvest and reuse systems are a good stormwater treatment practice when used in a treatment train. Under the Minnesota Construction Stormwater Permit GI, if Class D soils are present on the site infiltration practices cannot be used. Class A soils are the most desirable for infiltration but infiltration can also be successful with B or C soils. These notes are not mandates nor are they a complete list of what is the best practice for each site, site consideration needs will be addressed by the building design team.
--- Maybe add a chart indicating soil penetrability of different HSG groups —
The Pollution Control Agency allows for infiltration to be used as a credit source when meeting pollutant budgets for Total Suspended Solids (TSS) and Total Phosphorus (TP). The methodology for counting credits can be found here.
Additional Information: Water harvest and reuse systems are effective for use in class C and D soils Harvest and reuse systems can be incorporated in a useful and beneficial manner to site owners. An example of a well designed harvest and reuse system that serves multiple purposes can be found in Thailand at the Chulalongkorn University