Average rainfall during the month of January is found to be 58 mm. A Class A pan evaporation recorded an average of 8.12 mm/day near an irrigation reservoir. The average January inflow into the reservoir is 165 m3/s and the average irrigation demand during the month is 170 m3/s. The water level drops by 0.25 m in that month and the average surface area of the reservoir is 21,000 ha. Estimate the seepage through the banks and the dam during this month. Assume the pan coefficient of 0.7 for the month of January.
Given the net radiation, Rn = 204 W/m2,
Soil heat flux density, G = 0,
Mean daily temperature = 210C,
Humidity = 58%,
Wind velocity, u = 18 km/day,
All values measured at 2 m.
Calculate potential ET using the Penman-Monteith method
Take the value of as 0.065 kPa /oC.