At a water elevation of 6391 ft, Mono Lake has a volume of 2,939,000 ac-ft, and a surface area of 48,100 ac. Annual inputs to the lake include 8 in. of direct precipitation, runoff from gauged streams...

At a water elevation of 6391 ft, Mono Lake has a volume of 2,939,000 ac-ft, and a surface area of 48,100 ac. Annual inputs to the lake include 8 in. of direct precipitation, runoff from gauged streams of 150,000 ac-ft per year, and ungauged runoff and groundwater inflow of 37,000 ac-ft per year. Evaporation is 45 in. per year.

(A) Make a water budget showing inputs, in ac-ft per year and outputs in ac-ft per year. Does the input balance the output?

(B) Will the average lake level rise or fall from the 6391-ft elevation over the long term?

(C) What would be the lake surface area when the inputs balance the outputs? (Assume that the volume of gauged and ungauged runoff and ground-water inflows remain constant with a change in lake surface area.)

(D) What is the residence time* for water in Mono Lake when the water surface is at 6391 ft?