Abstract
AbstractResidence times of tracers in rectangular seepage lakes with wind-driven circulation are investigated in this paper. The key dimensionless parameters are DTW/qLT2 and VW/qLL, in which DT is the diffusion coefficient transverse to the wind direction, W is the dimension of the lake aligned with the direction of groundwater inflow/outflow, q is the specific discharge of groundwater entering and leaving the lake, LL and LT are the lake dimensions in the wind direction and transverse to the wind direction, respectively, and V is the wind speed. The well-mixed approximation in rectangular lakes is reasonable when DTW/qLT2>1 and VW/qLL≫1. Under these conditions, tracer particles are distributed uniformly over the outflow surface, and the probability distribution of tracer residence times can be estimated theoretically without the need to develop a numerical mixing model for the lake.
