m |
m |
||
(14 intermediate revisions by the same user not shown) | |||
Line 7: | Line 7: | ||
**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. | **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 | **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 restricted to 4 inches | + | **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 | *Volume retention | ||
**Maximize media depth to increase retention | **Maximize media depth to increase retention | ||
Line 19: | Line 19: | ||
*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 | ||
Line 32: | Line 32: | ||
*Applicability | *Applicability | ||
**Limited to 1.5 foot ponding depth | **Limited to 1.5 foot ponding depth | ||
− | **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"> '''BMP'''</span> 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 | ||
− | **Raise the underdrain to the extent possible to maximize infiltration | + | **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 evapotranspiration by placing a tree into the BMP | + | **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 | **Phosphorus | ||
− | ***Use Mix C or D to maximize phosphorus removal. Mixes A and B require testing and will likely fail the test. | + | ***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. |
− | ***Incorporate iron into the system | + | ***[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] | [https://stormwater.pca.state.mn.us/index.php?title=Bioretention Link to bioretention] | ||
Line 48: | Line 48: | ||
*Applicability | *Applicability | ||
**More effective than bioinfiltration because depth is only limited by drawdown time requirement | **More effective than bioinfiltration because depth is only limited by drawdown time requirement | ||
− | **Not as effective as underground systems in highly urban and ultra-urban environments | + | **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 | **May have limited ability to remove pollutants on highly permeable (A) soils | ||
*Volume retention | *Volume retention | ||
Line 59: | Line 59: | ||
*Applicability | *Applicability | ||
− | **A very effective BMP on highly permeable (A) soils. Less effective on B soils due to cost of construction and maintenance. | + | **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 highly urban and ultra-urban | + | **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 | **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 | *Volume retention | ||
Line 72: | Line 72: | ||
*Applicability | *Applicability | ||
**Very effective at reducing volume | **Very effective at reducing volume | ||
− | **Effective in highly urban and ultra-urban | + | **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) | **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 | **Should not route pervious runoff to permeable pavement and should limit impervious:pavement ratio to 2:1 due to maintenance needs | ||
Line 86: | Line 86: | ||
*Applicability | *Applicability | ||
− | **This is a good BMP in highly urban and ultra-urban | + | **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 media 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 | + | **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 | **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 (evapotranspiration), but make sure the tree size is practical for the site | + | **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. | **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) | **Coniferous trees increase ET and canopy interception (Note: they must be suitable for the site) | ||
Line 101: | Line 101: | ||
*Applicability | *Applicability | ||
− | **This is a good BMP in highly urban and ultra-urban | + | **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 media 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 | + | **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 | **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 (evapotranspiration), but make sure the tree size is practical for the site | + | **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. | **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) | **Coniferous trees increase ET and canopy interception (Note: they must be suitable for the site) | ||
Line 120: | Line 120: | ||
*Applicability | *Applicability | ||
− | *Swale side slope and swale main channel (with or without underdrain) act as a single BMP. 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 | + | *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) | **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 a good volume retention practice unless on A soils and/or designed with check dams or bioretention base | ||
− | **Not good for highly urban and ultra-urban | + | **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 | *Volume retention | ||
**Increase swale length to maximize volume retention | **Increase swale length to maximize volume retention | ||
− | **Check dams are the most effective way of capturing and infiltrating water on permeable soils | + | **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 | **Adding a bioretention base increase infiltration if underlying soils are permeable | ||
**Increasing the channel slope reduces infiltration | **Increasing the channel slope reduces infiltration | ||
Line 136: | Line 136: | ||
*Applicability | *Applicability | ||
− | **It is difficult to meet the retention requirement with this BMP | + | **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 | + | **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 ultra-urban | + | **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 | **Most effective when there are large green spaces that can be irrigated | ||
*Volume retention | *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. | **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 | **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 permeable soils, excess water will infiltrate. On other soils, to maximize volume reduction, choose “No” for the question asking about a user-defined irrigation rate. | + | **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 | **For vegetation, volume retention follows this order: Trees > turf = vegetables > forage > cereals | ||
**Retaining water on-site typically has a small effect on volume retention | **Retaining water on-site typically has a small effect on volume retention | ||
Line 154: | Line 154: | ||
*Applicability | *Applicability | ||
**Cannot be used to meet the Construction Stormwater permit volume retention requirement | **Cannot be used to meet the Construction Stormwater permit volume retention requirement | ||
− | **It is difficult to meet the retention requirement with this BMP | + | **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 | **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) | **Limited by the area that can effectively infiltrate water (see diagram on BMP Parameters tab for this BMP in the calculator) | ||
Line 164: | Line 164: | ||
==Wet swale, sand filter, constructed wetland, and constructed pond== | ==Wet swale, sand filter, constructed wetland, and constructed pond== | ||
− | These BMPs do not reduce volume | + | These <span title="one of many different structural or non–structural methods used to treat runoff"> '''BMPs'''</span> do not reduce volume |
==Summary table== | ==Summary table== | ||
− | The following table provides some summary information for BMPs in the MIDS calculator. Several cells show a range of values. These are explained below. | + | 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 | *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 | *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 media requirements. High volume retention capacity may require extensive media, which could be cost-prohibitive. | + | *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. | *Tree trench with underdrain may be limited by media requirements. Moderate volume retention capacity may require extensive media, which could be cost-prohibitive. | ||
Line 201: | Line 201: | ||
| Stormwater disconnection || Moderate || Moderate || No || Limited | | Stormwater disconnection || Moderate || Moderate || No || Limited | ||
|} | |} | ||
+ | |||
+ | [[Category:Level 3 - Models and modeling/Specific models/MIDS Calculator]] |
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.