AN EXPRESSION FOR THE VARIABLE BASIN LAG TIME
变动流域滞时方程

The basin lag time is an important factor in determining the basin hydrology. In this paper the basin lag time was expressed as a function of ratio of channel length from the centroid to the outlet of basin, divided by the velocity of flow at the gauging site at the time of passage of peak discharge. The channel length reflects the basin size and topographic characteristics, and the velocity characterizes the basin dynamic condition. The results of the test on five small basins were satisfactory.