The Matrimandir water harvesting project

Preparations are being made to realize a long intended goal for the Matrimandir gardens area, to harvest as much of the runoff water from the stormy winter monsoon rains as possible. Water harvesting is more and more a subject of interest in Auroville, as water levels in the underground aquifers are rapidly lowered during the summer due to intense usage by Auroville and the surrounding bioregion as a whole.

While it is true that recharge of the aquifers through rainfall is an important yearly occurrence, geologists note that less than 25% of the rainfall actually gets added to this recharge. Thus, if one can catch some of the rainfall and store and use it directly at the surface it could contribute greatly to our water balance in the city. Matrimandir is ideally suited for rainwater harvesting, as all three catchment areas in the gardens oval can be separately and easily dealt with. Out of the 86,000 sq. mt. of this oval, some are very near or below the Matrimandir. Water falling here is already collected in a large underground tank below the building and pumped back to the surface when needed by a set of pumps.

Water falling on the 4420 sq. mt. of the Amphitheater can also be easily collected. To do this, we will construct an underground sump in the line of the currently existing large drainage pipe, and redirect this water flow into our catchment area.

The third collection area is the web of paved pathways and plazas which lie between the gardens on site. These pathways all slope outwards, towards the edge of the garden oval. Thus here, at the edge of the gardens, we will now construct an open channel, about one meter wide and one kilometer long around the oval to collect this runoff water.

The water from all three sources will be directed in a large test pond which is to be made on the southeast edge of the gardens oval. It will be interesting indeed to make this experiment of collecting the runoff waters from the garden area. The catchment pond will have to be lined with a waterproof HDPE liner and will be stocked with fish and water plants to create a living and beautiful water body.

This project, which is being taken up now, will be monitored over the next few years: it will be a real test of the concept of rainwater harvesting in Auroville.

We note that the ancient villages surrounding Auroville, and throughout Tamil Nadu as a whole, had mastered the technique of seasonal water harvesting a thousand years ago! We are now trying to recreate this idea in more modern ways.