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.
Related Topics:
Computing Lag Time or Time of Concentration from Basin Data