A practical field technique for measuring reservoir evaporation utilizing mass-transfer theory

Studies of evaporation made in recent years nave provided values of the mass-transfer coefficient, N, in the equation E=Nut(e0—ea) for reservoirs having surface areas ranging from 1 to nearly 30,000 acres. The apparent correlation of N with reservoir surface area may in large part be associated with variations in the shape of the wind profile near the surface resulting from differences in surface roughness.

It appears that evaporation from many reservoirs can be determined with acceptable accuracy with a fairly simple system of instrumentation, data processing, and analysis.