Conjunctive Use of Water

Definition; Conjunctive use of water refers to the planned and coordinated use of both surface water (canal, tank, river) and groundwater in order to maximize water availability, improve irrigation efficiency, and minimize adverse effects such as waterlogging, salinity, or over-extraction.

Objectives of Conjunctive Use

• To ensure equitable distribution of irrigation water.
• To increase water use efficiency by combining two sources.
• To prevent waterlogging and salinity in canal command areas.
• To avoid over-exploitation of groundwater.
• To stabilize crop yields during rainfall fluctuations.

Need for Conjunctive Use in India

• Canal irrigation → leads to seepage, waterlogging, salinity.
• Groundwater irrigation → causes falling water table due to over-extraction.
• Rainfall → uncertain, seasonal.
  👉 Conjunctive use balances these three sources for sustainable production.

Modes/Practices of Conjunctive Use

• Simultaneous use; Farmers use canal water and groundwater together in rotation. Example: Irrigation with canal water at one critical stage and with groundwater at another.
• Alternative use; Canal water during canal-running period. Groundwater during lean period or canal closure.
• Mixing use; Poor quality groundwater (saline/alkaline) can be blended with canal water to bring it within permissible limits for irrigation.
• Spatial use; Some areas in command irrigated with canal water, others with groundwater, to avoid regional imbalance.

Advantages

• Reduces waterlogging and salinity in canal commands.
• Improves equitable distribution of water.
• Provides assured irrigation during dry spells.
• Enhances irrigation efficiency and crop productivity.
• Helps in utilizing poor-quality groundwater safely by blending.

Limitations

• Requires institutional planning and coordination (difficult at farmer level).
• Monitoring of groundwater quality and table is essential.
• Farmers often prefer groundwater due to flexibility → imbalance in practice.

Examples in India

• Punjab & Haryana → conjunctive use helps reduce waterlogging in canal commands and meet rice–wheat irrigation needs.
• Gujarat (Saurashtra region) → blending of saline groundwater with Narmada canal water.
• U.P. Canal Commands → rotation of canal + tube well irrigation (Warabandi + groundwater pumping).