Hydrodynamical connectivity in a small and deep tropical lake, a numerical study

The hydrodynamical connectivity of Lake Zirahuén was analyzed for the stratification (summer) and isothermal (winter) periods, in which the dispersion of passive particles was investigated for two hypothetical cases: i) a surface dispersion and ii) a deep resuspension, processes. The Lagrangian probability density functions were used to estimate the connectivity at a time scale of up to 30 days, and real drifting buoys were used to adjust the horizontal dispersion coefficients in the numerical model. In case i), the horizontal dispersion was similar between both seasons; only at the beginning during the first week was slightly different, but after day 10 and forward, they were alike due to the lake's small size. With respect to the vertical dispersion, the particles remain above 10 m deep during summer and travel along the total water column during winter, mainly from 10-20 m. For case ii), the horizontal dispersion was similar between both seasons. However, the vertical dispersion was inhibited by the thermal stratification during summer, where the particles do not reach depths above 20 m. In winter, the dispersion was more intense, and around day 3 they reached the total water column.