# WMS:Taylor Schwartz Lag Time Equation

Taylor and Schwartz (1952) developed an equation for estimating Snyder unit hydrograph parameters that was used for 20 different watersheds in the northeastern region of the U.S. Their equations are as follows:

$C_t = \frac {0.6}{ \sqrt {S}}$
$T_{LAG} = C_t \ast (L \ast L_{CA})^{0.3}$

where:

Ct = coefficient of watershed topography based on watershed slope.
S = weighted slope of maximum flow path in ft/ft.
TLAG = watershed lag time in hours.
L = maximum flow length in miles.
Lca = length to the centroid in miles.