Waterlogging and Salinity in the IGNP Command
In the Indira Gandhi Nahar command near Hanumangarh, 1,200 ha of the 8,000 ha command has had water table rise from 18 m to 3.5 m since canal lining was extended in 2010. About 300 ha now shows white salt crust and wheat yields have fallen by 40%. The canal runs at 85% efficiency; the soils are sandy loam over a calcium carbonate layer at 1.2 m. Farmers continue flood-irrigated wheat and paddy; paddy occupies 25% of the area. The irrigation department proposes lining the remaining distributaries at ₹22 crore, while the agriculture department proposes a subsurface drainage system at ₹9 crore for 300 ha. The state also wants a solar plant on 100 ha of the worst-affected land. Farmer groups resist drainage because it takes land and they fear losing the paddy income. The district must prepare an integrated plan within a five-year horizon.
1. Diagnose the causes of waterlogging and secondary salinisation in this command, and rank the proposed interventions.
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Diagnosis: excess application plus impeded drainage, not canal leakage alone.
The water table has risen to 3.5 m, which is within capillary reach for sandy loam; evaporation then draws salts upward and concentrates them at the surface, producing the white crust. Three causes interact. Canal seepage adds water continuously, and 85% efficiency means 15% is lost along the system. Flood irrigation of wheat and, especially, paddy adds far more water than the crop consumes. The calcium carbonate layer at 1.2 m restricts downward percolation, so the profile behaves like a shallow basin. Removing canal seepage without reducing irrigation would slow the rise but not reverse it.
Ranking: (1) Subsurface drainage for the 300 ha is the only measure that directly lowers the water table and flushes salts; it should be first because it treats the affected area at a manageable cost. (2) Lining remaining distributaries is useful but slower and more expensive per hectare; it should be sequenced after drainage, not instead of it. (3) Crop diversification away from paddy is essential, because paddy is the largest single water input and is agronomically marginal here. (4) Solar development on the 100 ha of degraded land is a sensible use of land that cannot be profitably farmed, but it must not become an excuse to abandon drainage for the rest.
An integrated plan should combine drainage, lining, warabandi water scheduling and a phased reduction of paddy.
2. How should the district address farmer resistance and design a monitoring plan for the integrated works?
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Resistance is rational and must be negotiated with evidence, not overridden.
Drainage takes 5–8% of land for trenches and may require an outlet, while paddy gives farmers a familiar income and fodder. The district should begin with a demonstration block of 20–30 ha, where water-table and yield data are shown for two seasons before expanding. Farmers whose land is taken for drains need compensation or land consolidation, and the drainage outlet must be legally secured so that neighbours cannot block it.
A package that pairs drainage with support for alternative crops is more acceptable than drainage alone. Provide assured marketing for cotton, guar or pulses, and explain that paddy yields are already falling by 40% in the salt-affected patches. Involve the panchayat and water-user association in siting drains, and publish the water table and salinity data.
Monitoring should include: water-table depth in a grid of observation wells, at least monthly and weekly during canal running; electrical conductivity of soil saturation extract before and after the monsoon; sodium adsorption ratio for irrigation water; crop yield and area under paddy; drain discharge and salt load removed; and the performance of lining reaches. A simple dashboard with thresholds will let the district adjust the five-year plan rather than discover failure at the end. The solar site should be monitored separately for groundwater effects, because levelling and fencing can alter local recharge.