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→Ferguson & Church (2004)Ferguson, R.I. and Church, M. 2004. A simple universal equation for grain settling velocity. Journal of sedimentary Research, 74(6), pp.933-937. for settling solids. http://geoweb.uwyo.edu/geol5330/FergusonChurch_GrainSettling_JSR04.pdf
====Ferguson & Church (2004)<ref>Ferguson, R.I. and Church, M. 2004. A simple universal equation for grain settling velocity. Journal of sedimentary Research, 74(6), pp.933-937. for settling solids. http://geoweb.uwyo.edu/geol5330/FergusonChurch_GrainSettling_JSR04.pdf</ref>====
====Ferguson & Church (2004)<ref>Ferguson, R.I. and Church, M. 2004. A simple universal equation for grain settling velocity. Journal of sedimentary Research, 74(6), pp.933-937. for settling solids. http://geoweb.uwyo.edu/geol5330/FergusonChurch_GrainSettling_JSR04.pdf</ref>====
Ferguson & Church's calculation meanwhile allows for designers to include the relationship between settling velocity and particle diameter size. A relationship for settling velocity that incorporates larger particles, such as sands with Reynolds Number (RE) > 10, has been developed by Ferguson and Church (2004) as shown in equation 10.2. Equation 10.2 becomes Stokes' Law at small particle diameters and results in a constant drag coefficient for large particle diameters.
Ferguson & Church's calculation meanwhile allows for designers to include the relationship between settling velocity and particle diameter size. A relationship for settling velocity that incorporates larger particles, such as sands with Reynolds Number (RE) > 10. The equation becomes Stokes' Law when particles have smaller diameters and allows for a constant drag coefficient to be applied for larger particle diameters.
* ''R'' = Specific gravity for solid in question (i.e. 1.58kg/cm<sup>3</sup> for sand)
* ''R'' = Specific gravity for solid in question (i.e. 1.58kg/cm<sup>3</sup> for sand)
* ''C'' = Typical constant for spherical solids (0.4) and (1.0) for sand grains}}
* ''C'' = Typical constant for spherical solids (0.4) and (1.0) for sand grains}}
See the table below for average settling velocities of different particle size ranges and particle types based on MOEE (1994)<ref>MOEE (1994). Stormwater management practices planning and design manual. Ministry of Environment and Energy, Ontario, Canada. </ref> and from Muschalla, 2014<ref>Muschalla, D., Vallet, B., Anctil, F., Lessard, P., Pelletier, G. and Vanrolleghem, P.A., 2014. Ecohydraulic-driven real-time control of stormwater basins. Journal of hydrology, 511, pp.82-91.</ref>
{| class="wikitable" style="width: 900px;"
|+'''Visual Indicators Framework - Bioretention/Swales'''
|-
!<br>'''Size Fraction (i)'''
!<br>'''Particle size range (µm)'''
!<br>'''Average settling velocity of particles in size fraction i, V<sub>si</sub> (m/s)'''
!<br>'''Fraction of total mass contained in size fraction i (%) - MOEE'''
!<br>'''Fraction of total mass contained in size fraction i (%) - measured'''
|-
|'''1'''
|x ≤ 20
|2.54E-06
|20
|83.4
|-
|'''2'''
|20 ≤ x ≤ 40
|1.30E-05
|10
|9.1
|-
|'''3'''
|40 ≤ x ≤ 60
|2.54E-05
|10
|4.4
|-
|'''4'''
|60 ≤ x ≤ 130
|1.27E-04
|20
|4.1
|-
|'''5'''
|130 ≤ x ≤ 400
|5.93E-04
|20
| -
|-
|'''6'''
|400 ≤ x ≤ 4000
|5.50E-03
|20
| -
|-
|}<br>
===Excess flow control===
===Excess flow control===