Question: a lake with a drainage area ad has a surface...
A lake with a drainage area AD has a surface area of AL and an average depth of zL. The long-term rates of precipitation and evapotranspiration for the portion of the drainage basin are PD and eD, respectively. For the lake itself the average rate of precipitation and evaporation are PL and eL, respectively. Average rate of stream outflow is Q. There is no groundwater inflow or outflow to the basin.
a. Identify the units (Length[L], Time [T], Mass [M], etc.) for each of the variables (i.e. Area has units of [L2]).
b. Write the water balance equation for the drainage basin (remember that the equation must have homogeneous units).
c. Using AD = 1000 km2, PD = 1,350 mm/yr, eD = 650 mm/yr, AL = 250 km2, PL = 975 mm/yr, Q = 15.8 m3/s, and zL = 25 m; use the equation from part b to calculate eL.