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This page provides information and recommendations for maximizing volume retention in the MIDS calculator. | This page provides information and recommendations for maximizing volume retention in the MIDS calculator. | ||
+ | |||
+ | ==Green roof== | ||
+ | [[File:MIDS calculator green roofs symbol.jpg|thumb|200px|alt=MIDS calculator symbol for green roofs|<font size=3>MIDS calculator symbol for green roofs</font size>]] | ||
+ | |||
+ | *Applicability | ||
+ | **Can have a <span title="A convential roof is a standard roof with an impervious surface, such as an asphalt roof"> '''conventional roof'''</span> draining to a <span title="Green roofs consist of a series of layers that create an environment suitable for plant growth without damaging the underlying roof system. Green roofs create green space for public benefit, energy efficiency, and stormwater retention/ detention."> '''green roof'''</span>, but the conventional roof area must be less than or equal to the green roof area. | ||
+ | **If the entire area is green roof (no conventional roof), then it is relatively easy to meet the volume retention requirement | ||
+ | **The <span title="Engineered media is a mixture of sand, fines (silt, clay), and organic matter utilized in stormwater practices, most frequently in bioretention practices. The media is typically designed to have a rapid infiltration rate, attenuate pollutants, and allow for plant growth."> [https://stormwater.pca.state.mn.us/index.php?title=Design_criteria_for_bioretention#Materials_specifications_-_filter_media '''media''']</span> depth is no longer restricted to 4 inches <span title="an extensive green roof has growing medium that is 6 inches or less deep"> '''(extensive roofs)'''</span>. However, if you make the media thickness greater than 4 inches, you get a popup reminding you that you are designing an <span title="an intensive green roof has growing medium that is 6 inches or more deep"> '''intensive roof'''</span>. For most green roofs, a media thickness of 4 inches will be sufficient to meet the volume requirement. | ||
+ | *Volume retention | ||
+ | **Maximize media depth to increase retention | ||
+ | **Limit the amount of conventional roof being routed to a green roof to maximize volume retention | ||
+ | |||
+ | [https://stormwater.pca.state.mn.us/index.php?title=Green_roofs Link to green roofs] | ||
==Bioretention without underdrain (bioinfiltration)== | ==Bioretention without underdrain (bioinfiltration)== | ||
− | [[File: | + | [[File:Bioinfiltration icon 2.png|200px|thumb|alt=MIDS symbol for bioinfiltration|<font size=3>Symbol used for bioretention basin without underdrain (bioinfiltration) in the MIDS calculator.</font size>]] |
*Applicability | *Applicability | ||
**Limited to 1.5 foot ponding depth | **Limited to 1.5 foot ponding depth | ||
− | **The 1.5 foot depth restriction limits infiltration on highly permeable soils | + | **The 1.5 foot depth restriction limits infiltration on <span title="Permeable soils have rapid infiltration rates, typically 0.5 inches/hr or greater. These would be Hydrologic Soil Group A soils."> '''highly permeable soils'''</span> |
− | **Diverse BMP that can be incorporated into many landscapes; provides multiple benefits (e.g. habitat, aesthetics) | + | **Diverse <span title="one of many different structural or non–structural methods used to treat runoff"> '''best management practice'''</span> (BMP) that can be incorporated into many landscapes; provides multiple benefits (e.g. habitat, aesthetics) |
− | **Not effective in highly urban and ultra-urban environments because of required space | + | **Not effective in <span title="Highly urban and ultra-urban settings have a large percentage of impermeable surface and typically have limited space to install surface BMPs. An example would be a downtown area."> '''highly urban and ultra-urban environments'''</span> because of required space |
*Volume retention | *Volume retention | ||
**Typically, you will want to maximize depth and limit surface area unless you are designing for other benefits, such as habitat | **Typically, you will want to maximize depth and limit surface area unless you are designing for other benefits, such as habitat | ||
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==Bioretention with underdrain (Biofiltration)== | ==Bioretention with underdrain (Biofiltration)== | ||
− | [[File:Symbol for biofiltration with an underdrain.jpg|300px|thumb|alt=Symbol for | + | [[File:Symbol for biofiltration with an underdrain.jpg|300px|thumb|alt=Symbol for bioretention basin (with underdrain)) used in MIDS calculator|<font size=3>Symbol for Bioretention basin (with underdrain) used in MIDS calculator.</font size>]] |
*Applicability | *Applicability | ||
**Limited to 1.5 foot ponding depth | **Limited to 1.5 foot ponding depth | ||
+ | **Diverse <span title="one of many different structural or non–structural methods used to treat runoff"> '''BMP'''</span> that can be incorporated into many landscapes; provides multiple benefits (e.g. habitat, aesthetics) | ||
+ | **Not effective in <span title="Highly urban and ultra-urban settings have a large percentage of impermeable surface and typically have limited space to install surface BMPs. An example would be a downtown area."> '''highly urban and ultra-urban environments'''</span> because of required space | ||
+ | *Volume retention | ||
+ | **Typically, you will want to maximize depth and limit surface area unless you are designing for other benefits, such as habitat | ||
+ | **Raise the <span title="An underground drain or trench with openings through which the water may percolate from the soil or ground above"> '''underdrain'''</span> to the extent possible to maximize infiltration | ||
+ | **Maximize <span title="Loss of water to the atmosphere as a result of the joint processes of evaporation and transpiration through vegetation"> '''evapotranspiration'''</span> by placing a tree into the BMP | ||
+ | **Phosphorus | ||
+ | ***Use [https://stormwater.pca.state.mn.us/index.php?title=Design_criteria_for_bioretention#Guidance_for_bioretention_media_composition Mix C or D] to maximize phosphorus removal. Mixes A and B require testing and will likely fail the test. | ||
+ | ***[https://stormwater.pca.state.mn.us/index.php?title=Soil_amendments_to_enhance_phosphorus_sorption Incorporate iron] into the system | ||
+ | |||
+ | [https://stormwater.pca.state.mn.us/index.php?title=Bioretention Link to bioretention] | ||
+ | |||
+ | ==Infiltration basin/infiltration trench== | ||
+ | [[File:MIDS symbol for infiltration.jpg|thumb|200px|alt=MIDS calculator symbol for infiltration basin|<font size=3>MIDS calculator symbol for infiltration basin.</font size>]] | ||
+ | *Applicability | ||
+ | **More effective than bioinfiltration because depth is only limited by drawdown time requirement | ||
+ | **Not as effective as underground systems in <span title="Highly urban and ultra-urban settings have a large percentage of impermeable surface and typically have limited space to install surface BMPs. An example would be a downtown area."> '''highly urban and ultra-urban environments'''</span> | ||
+ | **May have limited ability to remove pollutants on highly permeable (A) soils | ||
+ | *Volume retention | ||
+ | **Typically, you will want to maximize depth and limit surface area unless you are designing for other benefits, such as habitat | ||
+ | |||
+ | [https://stormwater.pca.state.mn.us/index.php?title=Infiltration Link to infiltration basin/trench] | ||
+ | |||
+ | ==Underground infiltration== | ||
+ | [[File:Symbol for underground infiltration in MIDS calculator.png|right|thumb|200 px|alt=This image shows the Symbol for underground infiltration in MIDS calculator|<font size=3>Symbol for underground infiltration in MIDS calculator</font size>]] | ||
+ | |||
+ | *Applicability | ||
+ | **A very effective <span title="one of many different structural or non–structural methods used to treat runoff"> '''BMP'''</span> on highly permeable (A) soils. Less effective on B soils due to cost of construction and maintenance. | ||
+ | **Effective in <span title="Highly urban and ultra-urban settings have a large percentage of impermeable surface and typically have limited space to install surface BMPs. An example would be a downtown area."> '''highly urban and ultra-urban environments'''</span> | ||
+ | **Can be difficult to make calculations and use the calculator to size the practice since calculations are made outside the calculator, unless you have specifications from the manufacturer | ||
+ | *Volume retention | ||
+ | **Typically, you will want to maximize depth and limit surface area unless you are designing for other benefits, such as habitat | ||
+ | |||
+ | [https://stormwater.pca.state.mn.us/index.php?title=Infiltration Link to infiltration basin/trench] | ||
+ | |||
+ | ==Permeable pavement== | ||
+ | [[File:MIDS calculator symbol permeable pavement.jpg|thumb|300px|alt=MIDS calculator symbol for permeable pavement|<font size=3>MIDS calculator symbol for permeable pavement.</font size>]] | ||
+ | |||
+ | *Applicability | ||
+ | **Very effective at reducing volume | ||
+ | **Effective in <span title="Highly urban and ultra-urban settings have a large percentage of impermeable surface and typically have limited space to install surface BMPs. An example would be a downtown area."> '''highly urban and ultra-urban environments'''</span> | ||
+ | **Limited to 5:1 ratio for impervious:permeable pavement area (Note: permeable pavement is included in impermeable acreage in the calculator) | ||
+ | **Should not route pervious runoff to permeable pavement and should limit impervious:pavement ratio to 2:1 due to maintenance needs | ||
+ | **Generally cannot be used in high traffic areas or with heavy loads | ||
+ | *Volume retention | ||
+ | **Typically will want to maximize surface area versus making the BMP deeper since the BMP is typically able to meet volume retention requirements | ||
+ | **To increase volume retained, unless required, do not compact subsoil | ||
+ | |||
+ | [https://stormwater.pca.state.mn.us/index.php?title=Permeable_pavement Link to permeable pavement] | ||
+ | |||
+ | ==Tree trench system/box without underdrain== | ||
+ | [[File:Symbol for tree trench.png|300px|thumb|alt=Symbol for tree trench system-treebox|<font size=3>Symbol used for the tree trench system/box (w/o underdrain) BMP in the MIDS calculator. Note the symbol shows multiple trees since tree trench systems contain multiple trees.</font size>]] | ||
+ | |||
+ | *Applicability | ||
+ | **This is a good <span title="one of many different structural or non–structural methods used to treat runoff"> '''BMP'''</span> in <span title="Highly urban and ultra-urban settings have a large percentage of impermeable surface and typically have limited space to install surface BMPs. An example would be a downtown area."> '''highly urban and ultra-urban environments'''</span> | ||
+ | **Water is stored in the <span title="Engineered media is a mixture of sand, fines (silt, clay), and organic matter utilized in stormwater practices, most frequently in bioretention practices. The media is typically designed to have a rapid infiltration rate, attenuate pollutants, and allow for plant growth."> [https://stormwater.pca.state.mn.us/index.php?title=Design_criteria_for_bioretention#Materials_specifications_-_filter_media '''media''']</span> instead of being ponded. Thus, the amount of water stored is less than bioinfiltration or infiltration basin per unit volume because solids are taking up some of the available storage space | ||
+ | **Diverse BMP that can be incorporated into many landscapes; provides multiple benefits (e.g. habitat, aesthetics) | ||
+ | *Volume retention | ||
+ | **This is typically an underground BMP, so the system could be designed to maximize volume retention by maximizing either area or depth | ||
+ | **Volume retention increase with tree size <span title="Loss of water to the atmosphere as a result of the joint processes of evaporation and transpiration through vegetation"> '''(evapotranspiration)'''</span>, but make sure the tree size is practical for the site | ||
+ | **Determine the soil volume needed to maximize tree growth. This can be done by entering the number of trees in the appropriate cell in the calculator and examining the cells displaying volume reduction for ET and the soil volume per tree. Enter the tree number that maximizes ET while maximizing soil volume per tree. | ||
+ | **Coniferous trees increase ET and canopy interception (Note: they must be suitable for the site) | ||
+ | |||
+ | [https://stormwater.pca.state.mn.us/index.php?title=Trees Link to information on tree trenches] | ||
+ | |||
+ | ==Tree trench system/box with underdrain== | ||
+ | [[File:Symbol for tree trench with underdrain.jpg|300px|thumb|alt=symbol for tree trench system-treebox with underdrain|<font size=3>Symbol used in the MIDS calculator to represent the tree trench system-tree box BMP with an underdrain. Note the symbol shows multiple trees since tree trench systems contain multiple trees.</font size>]] | ||
+ | |||
+ | *Applicability | ||
+ | **This is a good <span title="one of many different structural or non–structural methods used to treat runoff"> '''BMP'''</span> in <span title="Highly urban and ultra-urban settings have a large percentage of impermeable surface and typically have limited space to install surface BMPs. An example would be a downtown area."> '''highly urban and ultra-urban environments'''</span> | ||
+ | **Water is stored in the <span title="Engineered media is a mixture of sand, fines (silt, clay), and organic matter utilized in stormwater practices, most frequently in bioretention practices. The media is typically designed to have a rapid infiltration rate, attenuate pollutants, and allow for plant growth."> [https://stormwater.pca.state.mn.us/index.php?title=Design_criteria_for_bioretention#Materials_specifications_-_filter_media '''media''']</span> instead of being ponded. Thus, the amount of water stored is less than bioinfiltration or infiltration basin per unit volume because solids are taking up some of the available storage space | ||
**Diverse BMP that can be incorporated into many landscapes; provides multiple benefits (e.g. habitat, aesthetics) | **Diverse BMP that can be incorporated into many landscapes; provides multiple benefits (e.g. habitat, aesthetics) | ||
− | |||
*Volume retention | *Volume retention | ||
− | ** | + | **This is typically an underground BMP, so the system could be designed to maximize volume retention by maximizing either area or depth |
− | ** | + | **Volume retention increase with tree size <span title="Loss of water to the atmosphere as a result of the joint processes of evaporation and transpiration through vegetation"> '''(evapotranspiration)'''</span>, but make sure the tree size is practical for the site |
− | ** | + | **Determine the soil volume needed to maximize tree growth. This can be done by entering the number of trees in the appropriate cell in the calculator and examining the cells displaying volume reduction for ET and the soil volume per tree. Enter the tree number that maximizes ET while maximizing soil volume per tree. |
+ | **Coniferous trees increase ET and canopy interception (Note: they must be suitable for the site) | ||
**Phosphorus | **Phosphorus | ||
***Use Mix C or D to maximize phosphorus removal. Mixes A and B require testing and will likely fail the test. | ***Use Mix C or D to maximize phosphorus removal. Mixes A and B require testing and will likely fail the test. | ||
***Incorporate iron into the system | ***Incorporate iron into the system | ||
− | [https://stormwater.pca.state.mn.us/index.php?title= | + | [https://stormwater.pca.state.mn.us/index.php?title=Trees Link to information on tree trenches] |
+ | |||
+ | ==Swales== | ||
+ | [[File:Symbol for swale with no underdrain.png|300px|thumb|alt=symbol for swale with no underdrain|<font size=3>Symbol for Swale main channel (without an underdrain) used in the MIDS calculator.</font size>]] | ||
+ | [[File:Symbol for swale side slope.jpg|200px|thumb|alt=Schematic used as a symbol for swale side slope|<font size=3>Symbol for Swale side slope used in the MIDS calculator</font size>]] | ||
+ | |||
+ | *Applicability | ||
+ | *Swale side slope and swale main channel (with or without underdrain) act as a single <span title="one of many different structural or non–structural methods used to treat runoff"> '''BMP'''</span>. Make sure impervious and pervious acres are applied to the side slope and not the main channel, unless water is routed directly to a main channel. Swale lengths for side slopes and main channel should be the same for a swale system | ||
+ | **Diverse BMP that can be incorporated into many landscapes; provides multiple benefits (e.g. habitat, aesthetics) | ||
+ | **Not a good volume retention practice unless on A soils and/or designed with check dams or bioretention base | ||
+ | **Not good for <span title="Highly urban and ultra-urban settings have a large percentage of impermeable surface and typically have limited space to install surface BMPs. An example would be a downtown area."> '''highly urban and ultra-urban environments'''</span> | ||
+ | *Volume retention | ||
+ | **Increase swale length to maximize volume retention | ||
+ | **Check dams are the most effective way of capturing and infiltrating water on <span title="Permeable soils have rapid infiltration rates, typically 0.3 inches/hr or greater. These would be Hydrologic Soil Group A and B soils."> '''permeable soils'''</span> | ||
+ | **Adding a bioretention base increase infiltration if underlying soils are permeable | ||
+ | **Increasing the channel slope reduces infiltration | ||
+ | |||
+ | [https://stormwater.pca.state.mn.us/index.php?title=Dry_swale_(Grass_swale) Link to information on swales] | ||
+ | |||
+ | ==Harvest and reuse/cistern== | ||
+ | [[File:Symbol used for harvest and reuse.jpg|thumb|300px|alt=symbol for harvest and reuse in the MIDS calculator|<font size=3>MIDS calculator symbol for harvest and reuse.</font size>]] | ||
+ | |||
+ | *Applicability | ||
+ | **It is difficult to meet the retention requirement with this <span title="one of many different structural or non–structural methods used to treat runoff"> '''BMP'''</span> | ||
+ | **Useful on <span title="low permeability soils typically have low infiltration rates, less than 0.1 inches per hour. These are Hydrologic Soil Group D soils"> '''low permeability soils'''</span> for reducing the volume delivered to downstream BMPs | ||
+ | **Can be used in <span title="Highly urban and ultra-urban settings have a large percentage of impermeable surface and typically have limited space to install surface BMPs. An example would be a downtown area."> '''highly urban and ultra-urban environments'''</span> where there are small green spaces to irrigate | ||
+ | **Most effective when there are large green spaces that can be irrigated | ||
+ | *Volume retention | ||
+ | **If there is sufficient space on the site, ponds allow for greater volume storage. Volume reductions with cisterns are typically limited by the storage capacity of the cistern. | ||
+ | **To maximize volume reduction, maximize the volume application area | ||
+ | **On A soils you can apply up to 2 inches per week. This will exceed plant demand but because of the <span title="Permeable soils have rapid infiltration rates, typically 0.5 inches/hr or greater. These would be Hydrologic Soil Group A soils."> '''highly permeable soils'''</span>, excess water will infiltrate. On other soils, to maximize volume reduction, choose “No” for the question asking about a user-defined irrigation rate. | ||
+ | **For vegetation, volume retention follows this order: Trees > turf = vegetables > forage > cereals | ||
+ | **Retaining water on-site typically has a small effect on volume retention | ||
+ | |||
+ | [https://stormwater.pca.state.mn.us/index.php?title=Stormwater_and_rainwater_harvest_and_use/reuse Link to information on stormwater harvest and reuse] | ||
+ | |||
+ | ==Stormwater disconnection== | ||
+ | [[File:Symbol for Stormwater Disconnection in MIDS calculator.png|right|thumb|200 px|alt=This image shows a symbol for Stormwater Disconnection in MIDS calculator|<font size=3>Symbol for Stormwater Disconnection in MIDS calculator</font size>]] | ||
+ | |||
+ | *Applicability | ||
+ | **Cannot be used to meet the Construction Stormwater permit volume retention requirement | ||
+ | **It is difficult to meet the retention requirement with this <span title="one of many different structural or non–structural methods used to treat runoff"> '''BMP'''</span> | ||
+ | **Useful on low permeability soils for reducing the volume delivered to downstream BMPs | ||
+ | **Limited by the area that can effectively infiltrate water (see diagram on BMP Parameters tab for this BMP in the calculator) | ||
+ | *Volume retention | ||
+ | **Maximize the impervious area delivering water to the practice | ||
+ | **Maximize the pervious area (NOTE: this cannot exceed the pervious acres entered in the Watershed tab for this BMP) | ||
+ | |||
+ | [https://stormwater.pca.state.mn.us/index.php?title=Turf Link to information on stormwater impervious disconnection] | ||
− | == | + | ==Wet swale, sand filter, constructed wetland, and constructed pond== |
+ | These <span title="one of many different structural or non–structural methods used to treat runoff"> '''BMPs'''</span> do not reduce volume | ||
+ | ==Summary table== | ||
+ | The following table provides some summary information for <span title="one of many different structural or non–structural methods used to treat runoff"> '''BMPs'''</span> in the MIDS calculator. Several cells show a range of values. These are explained below. | ||
+ | *Bioretention without underdrain, because of the depth limitation, has moderate retention capacity on A soils compared to other infiltration practices which can be built deeper to infiltrate more water | ||
+ | *Swale main channel has low infiltration capacity on low permeability soils, but high capacity on A soils when check dams are used | ||
+ | *Tree trench without underdrain is an effective infiltration practice but design may be limited by <span title="Engineered media is a mixture of sand, fines (silt, clay), and organic matter utilized in stormwater practices, most frequently in bioretention practices. The media is typically designed to have a rapid infiltration rate, attenuate pollutants, and allow for plant growth."> [https://stormwater.pca.state.mn.us/index.php?title=Design_criteria_for_bioretention#Materials_specifications_-_filter_media '''media''']</span> requirements. High volume retention capacity may require extensive media, which could be cost-prohibitive. | ||
+ | *Tree trench with underdrain may be limited by media requirements. Moderate volume retention capacity may require extensive media, which could be cost-prohibitive. | ||
+ | {| class="wikitable" | ||
+ | |- | ||
+ | ! BMP !! Volume reduction capacity (total) !! Volume reduction capacity (per unit BMP area) !! Ultra-urban applicability !! Multiple benefit applicability | ||
+ | |- | ||
+ | | Green roof || Low || High || Yes || Yes | ||
+ | |- | ||
+ | | Bioretention w/o underdrain || Moderate || Moderate-high || No || Yes | ||
+ | |- | ||
+ | | Bioretention w/underdrain || Low || Low || No || Yes | ||
+ | |- | ||
+ | | Infiltration basin/trench || High || High || No || Limited | ||
+ | |- | ||
+ | | Underground infiltration || High || High || Yes || Limited | ||
+ | |- | ||
+ | | Permeable pavement || Low || High || Yes || Limited | ||
+ | |- | ||
+ | | Tree trench w/o underdrain || Moderate-high || High || Yes || Yes | ||
+ | |- | ||
+ | | Tree trench w/underdrain || Low-moderate || Low || Yes || Yes | ||
+ | |- | ||
+ | | Swale main channel || Low-high || Low-high || No || Yes | ||
+ | |- | ||
+ | | Swale main channel w/ underdrain || Low || Low || No || Yes | ||
+ | |- | ||
+ | | Harvest and reuse/cistern || Moderate || Moderate || Yes || Limited | ||
+ | |- | ||
+ | | Stormwater disconnection || Moderate || Moderate || No || Limited | ||
+ | |} | ||
− | + | [[Category:Level 3 - Models and modeling/Specific models/MIDS Calculator]] | |
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This page provides information and recommendations for maximizing volume retention in the MIDS calculator.
Link to infiltration basin/trench
Link to infiltration basin/trench
Link to information on tree trenches
Link to information on tree trenches
Link to information on stormwater harvest and reuse
Link to information on stormwater impervious disconnection
These BMPs do not reduce volume
The following table provides some summary information for BMPs in the MIDS calculator. Several cells show a range of values. These are explained below.
BMP | Volume reduction capacity (total) | Volume reduction capacity (per unit BMP area) | Ultra-urban applicability | Multiple benefit applicability |
---|---|---|---|---|
Green roof | Low | High | Yes | Yes |
Bioretention w/o underdrain | Moderate | Moderate-high | No | Yes |
Bioretention w/underdrain | Low | Low | No | Yes |
Infiltration basin/trench | High | High | No | Limited |
Underground infiltration | High | High | Yes | Limited |
Permeable pavement | Low | High | Yes | Limited |
Tree trench w/o underdrain | Moderate-high | High | Yes | Yes |
Tree trench w/underdrain | Low-moderate | Low | Yes | Yes |
Swale main channel | Low-high | Low-high | No | Yes |
Swale main channel w/ underdrain | Low | Low | No | Yes |
Harvest and reuse/cistern | Moderate | Moderate | Yes | Limited |
Stormwater disconnection | Moderate | Moderate | No | Limited |
This page was last edited on 1 December 2022, at 20:16.