Answer:
combined evapotranspiration is 12.63 in/yr
for avg daily 0.035 in/day
Step-by-step explanation:
areas = 21000 sq. km
precipitation in year 2000 = 21 in/yr.
stream flow (Q) = 5000 ft³/s
runoff =

runoff=

runoff= 8.37 in/yr
total precipitation = 21 in/yr
hence
Evapotranspiration for watershed
ET= P - R
ET = 21 - 8.37 = 12.63 in/yr
so the combined evapotranspiration is 12.63 in/yr
for avg daily ET= 12.63/365 in/day
= 0.035 in/day