Question

What are the three disadvantages of tank irrigation?

Answer 1

1. High Evaporation Losses: Tanks are shallow, open reservoirs with large surface areas. Because they are directly exposed to the blistering tropical sun throughout the dry months, a huge amount of stored water is constantly lost through evaporation before it can be effectively used by crops.
2. Siltation and Capacity Reduction: Streams and surface runoff transport large amounts of mud, sand, and debris directly into tanks. Over time, this loose silt settles at the reservoir’s bottom, making the tank shallower and significantly limiting its total water-storage capacity unless expensive, frequent dredging is performed.
3. Unreliable and Seasonal Supply: Tanks are entirely dependent on direct rainfall from the seasonal monsoon to fill up. If the monsoon rains are delayed, inconsistent, or fail completely, the tanks would remain dry, leaving farmers without a backup irrigation source during important crop-growing seasons.