WMS:Putnam Lag Time Equation: Difference between revisions

Revision as of 20:53, 26 February 2013

Putnam (1972) developed a lag equation for watersheds around the Wichita, Kansas area as follows:

T_{LAG}=0.49{\sqrt {\frac {L}{\sqrt {S}}}}I_{a}^{-0.57}

where:

$T_{LAG}$ = lag time in hours.

$L$ = maximum flow length in miles.

$S$ = weighted slope along the maximum flow path in ft/mile.

$I_{a}$ = Impervious cover as a fraction.

This equation was used for watersheds ranging in size from 0.3 to 150 sq. miles, impervious covers less than 0.3 and a ratio of between 1.0 and 9.0.

@@ Line 1: / Line 1: @@
 Putnam (1972) developed a lag equation for watersheds around the Wichita, Kansas area as follows:
-:[[Image:image118.gif]]
+:<math>T_{LAG} = 0.49 \sqrt { \frac {L}{ \sqrt {S}}} I_a^{-0.57}</math>
 where:

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