A look at traditional water harvesting techniques used across the country.india Updated: May 19, 2003 15:29 IST
The north Bengal rivers - Ganga and Teesta, are in the habit of changing course very often.
However, the people of the region, have deviced a way of cutting the embankment into small irrigation channels called jampoi from the streams which seemed suitable.
The channels have to be watched carefully as they change course. The loose friable soils in many parts of north Bengal along with the changing course of the rivers make it impossible to have long canal network.
Inundation canal in Bengal is called kana nadi, literally translating to a blind river.
When a river floods, a breach is made in the embankment and canal or kana nadi is led away. Now, the elevation of the canal vis-à-vis the river bed is such that only the top layer of the flooded water is rooted out carrying silt and fishs leaving the course sand on the bed.
As the river further swells, the floodwaters from the inundation canal enter the fields. While fresh silt gets settled on the agricultural lands, the fish swim into the lakes and tanks feeding on larva of mosquitoes, thereby, keeping malaria in check.