WMS:Eagleson Lag Time Equation: Difference between revisions

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where:
where:


<math>T_{LAG}</math> = watershed lag time in hours.
''T<sub>LAG</sub>'' = watershed lag time in hours.


<math>L</math> = maximum flow length in miles.
''L'' = maximum flow length in miles.


<math>L_{ca}</math> = length to the centroid in miles.
''L<sub>ca</sub>'' = length to the centroid in miles.


<math>S</math> = weighted average slope of the maximum flow path in ft/mile.
''S'' = weighted average slope of the maximum flow path in ft/mile.




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*Areas from 0.22 to 7.5 square miles.
*Areas from 0.22 to 7.5 square miles.
*<math>L</math> from 1 to 7 miles.
*''L'' from 1 to 7 miles.
*<math>L_{ca}</math> from 0.3 to 3 miles.
*''L<sub>ca</sub>'' from 0.3 to 3 miles.
*<math>S</math> from 6 to 20 ft/mile.
*''S'' from 6 to 20 ft/mile.
*Impervious cover from 33 to 83 percent.
*Impervious cover from 33 to 83 percent.


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{{WMSMain}}
{{WMSMain}}
[[Category:Equations|E]]
[[Category:Equations|Eagleson]]
 
[[Category:WMS Basins|Eagleson]]
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Revision as of 16:05, 7 December 2016

Eagleson’s method (1962) for computing lag time in completely storm-sewered watersheds is given as follows:

where:

TLAG = watershed lag time in hours.

L = maximum flow length in miles.

Lca = length to the centroid in miles.

S = weighted average slope of the maximum flow path in ft/mile.


The typical characteristics of watersheds for which the Eagleson method was applied include the following:

  • Areas from 0.22 to 7.5 square miles.
  • L from 1 to 7 miles.
  • Lca from 0.3 to 3 miles.
  • S from 6 to 20 ft/mile.
  • Impervious cover from 33 to 83 percent.


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