POKKALI

Sluice gates are used to regulate farm water in and out of the Pokkali Farms aligned with daily tidal sea level swings. It consists of a narrow channel (typically 2x8ft) wide opening from the canal or lake in to the farm. The channel water flow is regulated by simply lowering or raising several stacked rectangular wooden planks (typically 6x24inches) in and out of the sluice gate. Sluice gate channel sidewalls are typically made of wood as well with natural clay holding it in place. More recently concrete sidewalls have been built for longevity and reduced maintenence.

Automated Sluice Gate Control One-Way Valve (Aalam | ആലം)

A one-way sliice control valve, known as Aalam, is fabricated using wood planks and traditionally used by farmers to regulate water level in Pokkali farms synchronized with tidal flows during cultivation season. This valve opens up during low tides under water pressure from the farm to drain excess accumulated rain water in the farm. Likewise during high tides the valve closes shut with external water pressure and prevents canal salt water from entering the farm during cultivation season. Placement of the valve controls water level in the farm. See following illustrations with specifications, fabrication steps and example farm deployment.

Draining of Farms

April to May summertime farm preparation is essential for a successful Pokkali harvest outcome. This includes reinforcing of inner and outer boundaries (cheras) and sluice gates to prevent breaches and flooding, plugging of leaks, tilling and ploughing of dry clay farm soil, mounds and channel creation for sowing, clearing wild foliage along boundaries to prevent nesting of birds, insects and rodent pests - all carried out prior to onset of monsoon in late May or early June. A critical requirement is the compliance of annual District Collector/PLDA Chairman’s directive to drain (de-water) farms starting April-14th in all Pokkali Padasekharams for needed farm preparation in the summer months.

PLDA Pokkali Farming Draining Directive

Non Compliance Issues

Non-compliance of timely draining of farm and needed farm preparatons is a root cause of Pokkali farming crop loss. This directive is blatantly and openly ignored every year by Farm owners, Prawn farmers (Kettukarans) and Padasekharam Committee officials often in collusion with local Agriculture Officers, Panchayath officials and vested interest lobbies of fisheries and tourism to continue Prawn Farming through the summer months resulting in perpetual state of fallow farms. Without needed farm preparation, misleading photographs and reasons for crop failure are routinely submitted to claim free govt crop loss compensation that is treated as a regular source of income and to continue unlicensed Prawn farming from April to November.