Question

A lake with a drainage area A_D has a surface area of A_L and an average depth of z_L. The long-term rates of precipitation and evapotranspiration for the portion of the drainage basin are P_D and e_D, respectively. For the lake itself the average rate of precipitation and evaporation are P_L and e_L, 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 A_D = 1000 km², P_D = 1,350 mm/yr, e_D = 650 mm/yr, A_L = 250 km², P_L = 975 mm/yr, Q = 15.8 m³/s, and z_L = 25 m; use the equation from part b to calculate e_L.

Answer 1

mm 15-a Po LT LT → Pou"fla lion.atyti Lo ke PL= mm]yn

3 b) ->(st }L = 25 m PD 135D mm

135403 3-))10 6.2 5 x (03 eL 3 e eapain to lake