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Flow path length is important only if high flows are not <span title="Stormwater runoff in excess of the design flow, which is diverted around a stormwater structure"> '''bypassed'''</span>. Below are recommendations from other states or localities.
 
Flow path length is important only if high flows are not <span title="Stormwater runoff in excess of the design flow, which is diverted around a stormwater structure"> '''bypassed'''</span>. Below are recommendations from other states or localities.
 
*North Carolina: The geometry of the cell shall be such that width, length, or radius are not less than 10 feet. This is to provide sufficient space for plants.
 
*North Carolina: The geometry of the cell shall be such that width, length, or radius are not less than 10 feet. This is to provide sufficient space for plants.
*[http://vwrrc.vt.edu/swc/april_22_2010_update/DCR_BMP_Spec_No_9_BIORETENTION_FinalDraft_v1-8_04132010.htm Virginia]: Length of shortest flow path to overall length is 0.3 for Level 1 Design and 0.8 for Level 2 Design
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*[https://swbmpvwrrc.wp.prod.es.cloud.vt.edu/wp-content/uploads/2017/11/BMP-Spec-No-9_BIORETENTION_v1-9_03012011.pdf Virginia]: Length of shortest flow path to overall length is 0.3 for Level 1 Design and 0.8 for Level 2 Design
*[http://www.dakotacountyswcd.org/pdfs/Dakota%20LID%20Standards%20Revised%2002-09-12.pdf Dakota County Soil and Water Conservation District]: Where <span title="A stormwater system in which part or all of the stormwater runoff is diverted from the primary treatment practice. Partial diversion is employed for bypass runoff, which is runoff in excess of the designed treatment volume of the practice. Full offline diversion is employed as a temporary means to divert all runoff from a stormwater practice, typically to avoid erosion of exposed soil or establishment of vegetation."> '''offline'''</span> designs are not achievable, bioretention practices shall be designed to route high flows on the shortest flow path across the cell to provide the least disturbance and displacement of the <span title="The volume of water that is treated by a BMP."> [https://stormwater.pca.state.mn.us/index.php?title=Water_quality_criteria '''Water Quality Volume''']</span> to be treated. Energy dissipation to avoid high flow velocity turbulence is required.
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*Dakota County Soil and Water Conservation District: Where <span title="A stormwater system in which part or all of the stormwater runoff is diverted from the primary treatment practice. Partial diversion is employed for bypass runoff, which is runoff in excess of the designed treatment volume of the practice. Full offline diversion is employed as a temporary means to divert all runoff from a stormwater practice, typically to avoid erosion of exposed soil or establishment of vegetation."> '''offline'''</span> designs are not achievable, bioretention practices shall be designed to route high flows on the shortest flow path across the cell to provide the least disturbance and displacement of the <span title="The volume of water that is treated by a BMP."> [https://stormwater.pca.state.mn.us/index.php?title=Water_quality_criteria '''Water Quality Volume''']</span> to be treated. Energy dissipation to avoid high flow velocity turbulence is required.
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[[Category:Level 3 - Best management practices/Structural practices/Infiltration (trench/basin)]]
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[[Category:Level 3 - Best management practices/Specifications and details/Design criteria]]

Latest revision as of 22:45, 3 December 2022

Flow path length is important only if high flows are not bypassed. Below are recommendations from other states or localities.

  • North Carolina: The geometry of the cell shall be such that width, length, or radius are not less than 10 feet. This is to provide sufficient space for plants.
  • Virginia: Length of shortest flow path to overall length is 0.3 for Level 1 Design and 0.8 for Level 2 Design
  • Dakota County Soil and Water Conservation District: Where offline designs are not achievable, bioretention practices shall be designed to route high flows on the shortest flow path across the cell to provide the least disturbance and displacement of the Water Quality Volume to be treated. Energy dissipation to avoid high flow velocity turbulence is required.

This page was last edited on 3 December 2022, at 22:45.