The monsoons are on in this part of Tamil Nadu, and we are frequently getting to witness that astonishing multisensory symphony event of Nature - rain! Sure, we’ve all studied about evaporation and cloud formation, but it still seems like a miracle that so much water, and sound and light should come bursting out at us from above. Today’s discussion however, is not about what happens above, but what happens below. Its a common observation that on open land, water does not stagnant in one spot, but flows away in natural channels till it finds the lowest spot. Open and untouched countryside has undulations that facilitate the collection of water in the lowest spots, and this is how lakes and ponds are formed and sustained. Since water channels naturally form in the softest and most permeable places, a large quantum of the water that flows through these channels first has the opportunity to percolate into the ground and enrich the water-table. If you’ve looked at large tracts of land, you would have seen how the natural shallow undulations, tracks and troughs (also called ‘swales’) meld beautifully together into a perfect rain-water collection and ground-water recharge system.
This system, if maintained and reinforced, can retain lakhs of litres of water within the landscape, instead of letting it drain away. One way of benefitting from these natural swales is to plant thirsty plants and trees within the undulations so that they can take up the water and as an added benefit, prevent soil erosion. This way of planting is called contour farming, and many communities around the world are now following it. One more way of not wasting the potential of the natural swales is to observe where the lowest point is, and then try to integrate it with the watering system in use in the land.
This is what organic farmer Alladi Mahadevan has done on his farm near Nedumaram in TN. With a minimal amount of trenching, he has connected together the natural water-channels in his farm so that all the water falls into one of the 3 wells on the land. “With this system, if I get even a few days of good rain in the monsoon, I can rest easy that the trees here will not be parched next summer. The path the water takes runs in different, circuitous curves, covering so much of the land. Everywhere the water passes, there is some percolation, and the land becomes water-rich. This makes so much more sense than randomly digging straight channels”. Mahadevan says he he has been able to retain 27 lakh litres of water in the landscape after creating this system of connected natural swales.The water in the well rose by over 10 feet after the introduction of the bio-swale system
Inspired by these natural swales, building bio-swales in city areas and gardens in now slowly gaining popularity. These bio-swales are being seen as ways to filter/clean runoff before further processing. They also add aesthetic appeal to the landscape. It’s good to see urban communities and planners looking beyond cemented storm-water drains, but if all farmers could look at the naturals swales in their own lands, and plan minimalistic interventions accordingly, we could well have a glorious water-revolution to look forward to in the coming years.