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{{alert|The anticipated construction period for this page is January through March, 2013|alert-under-construction}}
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{{alert|Many of the following pages have been updated and the links below redirect you to the updated page. The old pages can be accessed from the redirect page.|alert-info}}
  
==Infiltration Overview==
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Stormwater [[Glossary#I|infiltration]] practices capture and temporarily store stormwater before allowing it to infiltrate into the soil. Design variants include; the infiltration basin, the infiltration trench, the dry well and the underground infiltration system. As the stormwater penetrates the underlying soil, chemical, biological and physical processes remove pollutants and delay peak stormwater flows.
<p>''Natural or constructed depressions located in permeable soils that capture, store and infiltrate the volume of stormwater runoff associated with a particular design event.''</p>
 
  
[[file:Infiltration trench Lino Lakes.jpg|thumb|300px|alt=Photo of a Infiltration trench in Lino Lakes|Photo of a Infiltration trench in Lino Lakes]]
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[[file:Infiltration trench Lino Lakes.jpg|thumb|300px|alt=Photo of an infiltration trench in Lino Lakes|<font size=3>Photo of a Infiltration trench in Lino Lakes</font size>]]
  
[[file:Underground storage and infiltration - Stillwater.jpg|thumb|300px|alt=Photo of a Infiltration trench in Stillwater|Photo of a Infiltration trench in Stillwater]]
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Infiltration practices are applicable to sites with naturally permeable soils and a suitable distance to the seasonally high [[Glossary#G|groundwater]] table, bedrock or other impermeable layer. They may be used in residential and other urban settings where elevated [[Glossary#R|runoff]] volumes, pollutant loads, and runoff temperatures are a concern. In applications where the stormwater runoff has a particularly high pollutant load or where the soils have very high Infiltration rates, a significant amount of [[Glossary#P|pre-treatment]] should be provided to protect the groundwater quality. Sources that include potential stormwater [[potential stormwater hotspots|hotsposts]] (PSH) should not be introduced to Infiltration areas.
  
 
<u><font size=3>Infiltration trench articles</font size></u>
 
<u><font size=3>Infiltration trench articles</font size></u>
 
 
*[[Overview for Infiltration trench]]
 
*[[Overview for Infiltration trench]]
*[[Types of InfiltratioInfiltration trench]]  
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*[[Types of Infiltration trench]]  
 
*[[Design criteria for Infiltration trench]]
 
*[[Design criteria for Infiltration trench]]
 
*[[Construction specifications for Infiltration trench]]  
 
*[[Construction specifications for Infiltration trench]]  
*[[Operation and maintenance of Infiltration trench]]  
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*[[Operation and maintenance of Infiltration trench]]
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*[[Assessing the performance of infiltration]]
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*[[Calculating credits for infiltration trench]]
 
*[[Cost-benefit considerations for Infiltration trench ]]
 
*[[Cost-benefit considerations for Infiltration trench ]]
 
*[[External resources for Infiltration trench ]]
 
*[[External resources for Infiltration trench ]]
*[[References for Infiltration trench]]
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*[[References for infiltration]]
 
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*[[Requirements, recommendations and information for using infiltration basin/underground infiltration BMPs in the MIDS calculator]]
 
 
===Design Criteria:===
 
*Contributing drainage area
 
*Underlying soil types
 
*Depth to the water table, bedrock or other impeding layer
 
*Proximity to buildings, drinking water supplies, [[Glossary#K|Karst]] features, etc.
 
*Source of stormwater [[Glossary#R|runoff]]
 
 
 
===Benefits===
 
*Reduces volume of stormwater [[Glossary#R|runoff]]
 
*Increases ground water [[Glossary#R|recharge]]
 
*Improves surface water quality
 
*Provides thermal benefits (e.g. to cold water fisheries)
 
*Mimics pre-development hydrology
 
 
 
===Limitations===
 
*Unusual construction considerations
 
*Potential for [[Glossary#G|ground water]] contamination
 
*Tendency to lose effectiveness over time due to clogging – if not properly constructed or maintained
 
*Not recommended for areas with steep slopes
 
*May require landscaping: consideration should be given to periods on inundation and drought
 
 
 
===Description===
 
<p>In general terms, [[Glossary#I|infiltration]] systems can be described as natural or constructed depressions located in permeable soils that capture, store and infiltrate stormwater runoff within 48 hours. These depressions can be located at the surface of the ground (e.g. infiltration basin) or they can be designed as underground facilities (e.g. structural chamber or excavated pit filled with aggregate such as an infiltration trench). Typically, infiltration systems are designed with one or more [[Glossary#P|pre-treatment]] facilities or they are designed as off-line facilities.</p>
 
{{alert|[[glossary#I|Infiltration]] systems should be located in permeable soils and a minimum 3-foot distance is ''REQUIRED'' from the bottom of the seasonally high water table, bedrock or other impeding layer per the [http://www.pca.state.mn.us/index.php/water/water-types-and-programs/stormwater/construction-stormwater/index.html Minnesota Pollution Control Agency Construction General Permit (CGP)]]|alert-danger}}
 
 
 
<p>Dry wells and Trenches should be designed to handle the smaller, more frequent rainfall events. Stormwater associated with the larger rainfall events should bypass these practices by a separate pipe or an overflow device. Infiltration basins and underground infiltration systems should be designed to handle both the [[Glossary#W|water quality volume]] and as the water quantity volume.</p>
 
<p>Infiltration systems can be designed to address a number of stormwater management issues including: water quality, stormwater [[Glossary#G|runoff]] reduction, flow attenuation, [[Glossary#T|thermal impacts]] to cold water fisheries, and [[Glossary#G|groundwater]] [[Glossary#R|recharge]].</p>
 
 
 
===Maintenance Requirements===
 
*Establishment of native vegetation may require weeding, watering, pumping, replacement of plants and tree/shrub trimming
 
*Inspection and removal of [[Glossary#S|sediment]] accumulation
 
*Street sweeping of impervious areas adjacent to infiltration practices
 
*Avoid the application of fertilizer or herbicide in or near [[Glossary#I|infiltration]] practices
 
 
 
===SITE FACTORS===
 
[[file:Trench-storm.jpg|thumb|300px|alt=Schematic of Start of Storm Event - Initial runoff & storage|Schematic of Start of Storm Event - Initial runoff & storage]]
 
[[file:Trench-storage.jpg|thumb|300px|alt=Schematic of Duration of Storm Event - Storage & filtration/infiltration|Schematic of Duration of Storm Event - Storage & filtration/infiltration]]
 
[[file:Trench-infiltration.jpg|thumb|300px|alt=Schematic of inflitration trench following storm event - Remaining storage drawdown|Schematic of inflitration trench following storm event - Remaining storage drawdown]]
 
 
 
*Max Drainage Areas: Dry Well/ Trench/ Basin = 1/ 5/ 50 Acres
 
*Max. Site Slope = 20 percent
 
*Min. Depth to Bedrock = 3 feet
 
*Min. Depth to Seasonally High Water Table = 3 feet
 
*NRCS Soil Type *C & D soils have limited infiltration ability but can be used to match predevelopment conditions = A,B,C*,& D
 
*Freeze/ Thaw Suitability = Poor - Good
 
*Potential [[Glossary#H|Hotspot]] [[Glossary#R|Runoff]] = NO
 
  
===MANAGEMENT SUITABILITY===
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*<font size=3>[[Fact sheet|'''Fact sheet''']]</font size>
*Water Quality (V<sub>wq</sub>) = High
 
*Med. Channel Protection (V<sub>cp</sub>)
 
*[[Glossary#O|Overbank Flood Protection]] (Vp<sub>10</sub>) = Low/Med.
 
*[[Glossary#E|Extreme Flood]] Protection (Vp<sub>100</sub>) = Low
 
*[[Glossary#R|Recharge]] Volume (V<sub>re</sub>) = High
 
  
===MECHANISMS===
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==Related pages==
*Screening/ [[Glossary#F|Filtration]]
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*[[Understanding and interpreting soils and soil boring reports for infiltration BMPs]]
*Temperature Control
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*[[Determining soil infiltration rates]]
*Transpiration *if vegetated
 
*Soil [[Glossary#A|Adsorption]]
 
*Biological/ Micro. Uptake
 
  
===POLLUTION REMOVAL*===
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[[Category:Level 3 - Best management practices/Structural practices/Infiltration (trench/basin)]]
*Total Suspended Solids [[Glossary#T|(TSS)]] = 100 percent
 
*Nutrients - [[Glossary#T|Total Phosphorus]]/ = 100 percent
 
*Total Nitrogen = 100 percent
 
*Metals - Cadmium, Copper, Lead, and Zinc = 100 percent
 
*Pathogens - Coliform, Streptococci, E. Coli = 100 percent
 
*Toxins - Hydrocarbon = 100 percent
 
<p>Pollution removal addresses only the impact on surface water, as there could be some transfer of pollution to the soil layer and [[Glossary#G|groundwater]].</p>
 

Latest revision as of 16:25, 12 January 2023

Information: Many of the following pages have been updated and the links below redirect you to the updated page. The old pages can be accessed from the redirect page.

Stormwater infiltration practices capture and temporarily store stormwater before allowing it to infiltrate into the soil. Design variants include; the infiltration basin, the infiltration trench, the dry well and the underground infiltration system. As the stormwater penetrates the underlying soil, chemical, biological and physical processes remove pollutants and delay peak stormwater flows.

Photo of an infiltration trench in Lino Lakes
Photo of a Infiltration trench in Lino Lakes

Infiltration practices are applicable to sites with naturally permeable soils and a suitable distance to the seasonally high groundwater table, bedrock or other impermeable layer. They may be used in residential and other urban settings where elevated runoff volumes, pollutant loads, and runoff temperatures are a concern. In applications where the stormwater runoff has a particularly high pollutant load or where the soils have very high Infiltration rates, a significant amount of pre-treatment should be provided to protect the groundwater quality. Sources that include potential stormwater hotsposts (PSH) should not be introduced to Infiltration areas.

Infiltration trench articles

Related pages

This page was last edited on 12 January 2023, at 16:25.