Water is a very precious resource in the Auroville bio-region. The climate is semi-arid with the rain coming mainly during two monsoons; the South-West between July and September which provides 30% of the total annual rainfall and the North-East between October and December which provides 60% of the total annual rainfall. The remaining 10% of the rainfall occurs sporadically during the rest of the year. On a regional scale, the rainfall decreases from the coastline inland.With much of the rain coming during two relatively short periods flooding is common, especially during the second monsoon.
The yearly average rainfall between 1911 and 2001 was 1,192 mm. A maximum of 2,604 mm was recorded in 1943 and a minimum of 626 mm was recorded in 1952.
Auroville and its bio-region is running out of water as it is estimated that the actual extraction of water by bore wells from the underground aquifer is in the order of 15 times the natural recharge. In the 30 years of Auroville’s existence the ground water table has fallen by 45 meters. This has come about, not only because with the development of Auroville and the region, the number of bore-wells has increased, but because they are used with little regard to preserving the acquifer (the underground water source). Salt water has already been found in some of the underground water and it is urgent that ways are found to preserve what fresh water we have both above and below the ground.
For more details go to: http://www.auroville.org/contents/1921
Since in India agriculture uses more water than either industry or domestic users it is important that farmers find ways to use water most effectively. Buddha Garden is in an area of Auroville where the water table is very high so that provided we are careful with how we use the water we should have enough for our irrigation needs.
The problem is that irrigation systems that improve the efficiency of water use often cost a lot of money. Usually they do not lead to increased production to pay for it. Over the years we have been very lucky in getting grants to set up a more effective water system in Buddha Garden.
In the beginning Buddha Garden shared the pump and well at Siddhartha Farm. Over the years, however, it became clear that this was insufficient for our needs. In 2003 we therefore purchased a new solar pump so that Buddha garden now has its own pump, pumping water from the Siddhartha Farm well. In 2009 we moved the solar panels from Siddhartha farm (where we felt they were increasingly open to vandalism) to Buddha Garden. This has enabled us to set up a community electricity system with batteries and an inverter using the solar panels when they are not pumping water.
Soon after installing the new pump in 2004 we were able to completely refurbish the irrigation system using a grant from Stichting de Zaiier, an NGO in Holland. When we started Buddha Garden we used old irrigation pipes that had been used by another farm. Although we were very grateful for them, as they saved us a lot of money, after nearly three years they were in need of being changed. Many of the drip holes had got blocked and there were many holes caused by animals biting the pipes in their effort to get at the water in the pipes – especially during the hot season.
With this grant we were able to install three irrigation lines with drippers placed at 20cm intervals on each bed. We also arranged to have the water delivered to both ends of each irrigation pipe so that the water was equally spread in the pipe and therefore on the bed.
In the back yards we did not have enough money to install drip irrigation so we installed a sprinkler system instead which was much cheaper. The problem, however, is that sprinklers sprinkle the paths as well as the beds so weeds are much more of a nuisance. When cost is an issue it is better to have a sprinkler system than no system at all. Care has to be taken, however, asalthough some plants like leafy vegetables don’t mind having water on their leaves, some like tomatoes and brinjal don’t like it at all.
Early in 2005, Bastien, a French student from an agricultural university in France carried out a survey of the irrigation systems in several of the Auroville farms including Buddha Garden. He found that while the Buddha Garden irrigation system provided the crops with enough water it was being used indiscriminately and probably not very efficiently. This was, however, difficult to assess.
Watering was being carried out by turning on the whole irrigation system to the vegetable garden for a certain amount of time each day. There were changes according to the climate with a longer time being used in the hot period compared to the less hot periods but this was not very precise. There was no measuring device for determining how much water was being used although a rough estimate could be made according to how many tank-full were utilized. How much water went onto each bed could not be calculated easily as there were often differences in pressure depending on how much water was in the tank.
To use water more effectively Bastien suggested that the farm change the water system so that each bed had a separate outlet. Beds with young seedlings do not need as much water as mature plants so this would enable a more precise watering to be undertaken according to the need of the plants on the bed. This would be further enhanced if we put water meters in place, or at least calculated the amount of water going onto the bed by measuring the water coming out of the drippers over a fixed period.
In the light of Bastien’s research and recommendations we decided that we needed to use water much more consciously and decided that we would modify the irrigation system by putting independent outlets at each end of the bed. At each outlet there would be a tap together with a water meter so that the amount going on to the bed could be measured.This was not a cheap modification and at the time we were unable to pay for it out of the income from Buddha Garden. We were therefore very lucky to receive a grant from AVI-UK which enabled us to pay for it. There was not enough money to install water meters on every bed. We were able to install valves at the end of each bed that enables us to turn off the water to each bed should we need to do so.
We now have drip irrigation installed on all the raised vegetable beds, which are the heavy water users in Buddha Garden. When we grow food producing trees we try to confine ourselves to those that do not need a lot of water. At all times we are conscious of how much water we are using and try to use the least possible that enables the plants to grow successfully. Vivek has the idea for an automatic computer controlled watering system that would provide the plants with exactly the right amount of water, thus having the potential to save a lot of unnecessary watering. We live in hopes that one day we will be able to install this.
Water this could have been because of changes in the global weather system (in particular El Nino) or the result of climate change. Since with climate change ‘extreme weather events’ are likely to increase there is no way of predicting what is likely in the future.