For a given month, a $121\mathrm{.}4$ hectare lake $(1\mathrm{.}0$ hectare$=10,000$ m$2)$ has

$424$ l$/$s of inflow and $1325\mathrm{.}2$ m$3/$day of outflow. If the lake is free of

vegetation and its water surface has increased by $1\mathrm{.}62$ cm during

this month, it is required to write the relevant water budget

equation and to determine the evaporation depth in $($mm$)$ and in m$3$

for the following two cases:

a$)$ In case $1,$ neglect infiltration and neglect groundwater flow;

b$)$ In case $2,$ neglect groundwater flow and assume that the

infiltrated water volume is $30\%$ of the evaporated volume.