Evaporimeters

Q. An evaporation pan of $1.25m$ diameter placed in a catchment area receives $10mm$ rainfall. The total evaporation on that day is $5mm$. The net volume of water collected in the evaporation pan will be____ $c{m}^3$.

1. 6135

Q. A standard, ground-based evaporation pan, corresponding to Indian Standards, is installed at the banks of a surface reservoir. The water surface area on a particular day is 100 hectares. The recorded evaporation loss from the pan, on a certain day, is nearly 4.0 cm. What is the anticipated evaporation loss from the reservoir for that day?

1. $\left(1.8to2\right)\times {10}^4{m}^3\text{per day}$
2. $\left(2.5to2.75\right)\times {10}^4{m}^3\text{per day}$
3. $\left(3.0to3.25\right)\times {10}^4{m}^3\text{per day}$
4. $\left(3.8to4.05\right)\times {10}^4{m}^3\text{per day}$

Q. An irrigation canal is 80 km long. It has an average surface width of 15 m. If the evaporation measured in a Class A pan is 5 mm/day, the volume of water evaporated in a month of 30 days is: (take pan coefficient as 0.7)

1. $18000{\text{m}}^3$
2. $126000{\text{m}}^3$
3. $18000{\text{cm}}^3$
4. $126000{\text{cm}}^3$

Q. A reservoir receives 5 ha-m water and the loss due to evaporation from the pan is 11 cm. It receives the rainfall of 5 cm over its plan area of 100 ha. The decrease in the level is observed as 3 cm. Taking the pan factor as 0.7 loss due to seepage will be

1. 5 ha-m
2. 6 ha-m
3. 7.3 ha-m
4. 5.3 ha-m

Q. The average surface area of a lake in the month of June was 240 ha. The volume of water evaporated from this lake during this month was found to be 42.6 ha-m. Assuming calibrated pan coefficient to be 0.8, the pan evaporation during this month would be_____mm/day (round off to 1 decimal place).

1. 7.4