Large-Scale Drip Irrigation: Hilltop Tank Design for Indian Farm

Horticulturist in southern India: 5 ha farm (900 mango, 2,500 teak, 700 oil palm) on sloped laterite soil. Open well at bottom not feasible for direct drip (power, uneven pressure). Plans hilltop tank (100,000–250,000 L) for gravity drip. Needs tank design, pressure regulation, zoning.

Tank Construction Options

• Concrete: Most cost-effective where cement is available. Seal interior with 2–3 coats of cementitious sealer (e.g., Thoroseal).
• Lined earthen pond: Excavate, line with HDPE/EPDM geomembrane. Lower cost, larger volume possible.
• Steel/plastic tanks: Modular, faster, higher cost per liter.

Critical Design: Pressure Regulation on Slope

Every 4 m (≈13 ft) of elevation drop = ~0.4 bar (6 PSI) pressure gain. Install pressure regulators at intervals no greater than 4 m drop to equalize emitter flow.

Zoning by Crop

• Separate zones for mango, teak, oil palm—each has different water needs at each growth stage.
• Example: mango fruit sizing needs more water; teak may not.
• Drip allows precise control per zone.

Next Steps

Provide: available materials, elevation profile (meters), pipe sizes, emitter types. Then detailed hydraulic design can be outlined.