LESSON 2: Irrigation Losses and Efficiencies

Question 1

The irrigation water losses in canals; these are due to:

Answer 1

1. Evaporation from the water surface
2. Deep percolation to soil layers underneath the canals
3. Seepage through the bunds of the canals
4. Overtopping the bunds
5. Bund breaks
6. Runoff in the drain
7. Rat holes in the canal bunds

Question 2

The irrigation water losses in the field; these are due to:

Answer 2

1. Surface runoff, whereby water ends up in the drain
2. Deep percolation to soil layers below the root zone

Question 3

Represents the efficiency of water transport in canals

Answer 3

conveyance efficiency (ec)

Question 4

Represents the efficiency of
water application in the field.

Answer 4

field application efficiency (ea)

Question 5

Wind drift and evaporation from water droplets are almost exclusive to sprinkler systems

These losses occur between the time the water leaves the sprinkler nozzle and when the
remaining water reaches the soil.

Large portions of these losses leave the fields as water vapor, they are not always visible
and may be “out of sight and out of mind.” However, these water losses can be
significant, and evaporation is a non-recoverable loss.

Answer 5

Wind Drift and Evaporation

Question 6

Wetted crop canopy depends on the canopy size, percentage of the canopy that is wetted, and weather conditions such as temperature, humidity, and air movement.

Answer 6

Wetted Canopy Evaporation

Question 7

It is a source of water loss in most irrigation systems, but it is especially prevalent in surface irrigation systems. This excess water moves downward through the soil profile and drains deeper than the crop’s root zone. Therefore, the crop can no longer access this water.

Answer 7

Deep Percolation

Question 8

Is visible, and most irrigators can easily see and manage it.
Although runoff water quality is often degraded due to nutrient and sediment loading from running across fields, it is often collected in streams, ponds, or
drainage ditches and is reused downstream for irrigation, recreation, or wildlife habitat.

Answer 8

Runoff