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Role of groundwater in irrigation development

Short answer

Groundwater provides a dependable dry-season source when surface water is scarce, enabling supplementary irrigation and increasing cropping intensity. It allows farmers individual control over timing and amount, reduces conveyance losses, and when used conjunctively with canal water prevents waterlogging and salinity.

Briefly describe the role of ground water in irrigation development.

Groundwater is water stored in the pores and fractures of soil and rock below the water table. It is a major, reliable source for irrigation, especially where surface water is limited or seasonal.

Role in irrigation development

  1. Dependable dry-season source: Rivers and canals often carry little water in winter and spring. Wells give water when it is needed.
  2. Supplementary irrigation: Where canal water is short, tubewells give extra water for the second and third crops.
  3. Terai development: In Nepal's Terai the shallow aquifer allows shallow tubewells (STW) and deep tubewells (DTW). The Bhabar zone recharges the aquifer.
  4. Individual control: Farmers can irrigate at the time and amount they need, which raises yields.
  5. Quick and cheaper development: Small wells need less capital and time than large canal systems, and have no conveyance loss or large land acquisition.
  6. Conjunctive use: Using surface water and groundwater together lowers waterlogging and salinity by keeping the water table low.
  7. Drought protection: Stored groundwater reduces the risk of crop loss in dry years.

Limits

Over-pumping lowers the water table, energy cost is high, and water quality (salts, arsenic in some Terai districts) must be checked. Pumping should not exceed the recharge.

✓ Answer checked by Claude Sonnet 5.5

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