By Rakesh Koti
Tiruchengode in Tamil Nadu is called the borewell rig capital of India. With up to 20,000 borewell rigs digging originating from this area and travelling as far as Rajasthan, and digging anywhere between 1000 feet to 1400 feet daily for many months of the year across India, the amount of water being pumped from deep aquifers in the Earth is unimaginable.
Is this sustainable? It sometimes takes years for water to percolate from the surface into these deep-seated channels. How much more water-stressed will our nation become?
An ideal source of water is rainfall which has the better overall quality and can be immediately tapped. Considering a city of the size of Hyderabad with a population of 68 lakhs, and considering a daily water usage per capita at a conservative 135 litres, total annual water requirement is 33,507 Crore litres while the total rainfall falling on Hyderabad is about 50,000 Crore litres considering an annual average rainfall of 800 mm falling over 625 square km of land.
Only 50% of this can be tapped at full efficiency due to percolation, evaporation and other losses. This leaves a huge deficit of almost 15,000 crore litres. Where is this water coming from? Some of it should come from the groundwater table, some of it should come from the freshwater lakes and the rest is the deficit which makes up all the water-stressed days in our communities.
Bear in mind that this is the case when rainwater harvesting is happening at full scale. The reality is much worse.
The above picture is from the apartments that I live in. This is during the rains in May 2020. Even this huge amount of rainfall is not sufficient for such a high-density settlement (up to 140 homes per acre).
So how can the water woes be solved? Ruthless extraction of groundwater or diversion of rivers and lakes are definitely not sustainable alternatives. If we continue down this path, there will come a time when the resources are exhausted and living in cities will no longer be an option.
At Organo, our intent is to promote counter-urbanization and develop eco-habitats that are low-density settlements which depend on rainwater for most of their needs. For example, in Organo’s upcoming project, where the density is 3 units per acre, the above requirements translate to a total water demand of 7 lakhs annually per acre with a rainfall of 32 lakhs per acre on average. Could counter-urbanization and rainfall dependence be a potential solution for the water crisis? It could be.
Our attempt at water security starts with analyzing rainfall pattern over the last 40 years and identifying the year with the least amount of rainfall. Daily rainfall data was taken for this year and a detailed analysis was done to see how much storage is required for domestic water security in case such a famine condition repeats.
The target sizing of the tank was achieved using the analysis to determine daily water demand vs the amount of water run-off from the farmland and hardscapes – rooftops and roads. The longest period between two showers of rain was calculated and the sizing of the storage systems was done to cater to that period.
Attempts like this towards water security cannot be possible unless a holistic approach is taken to first, reduce water demand, develop low-density communities, make people sensitive towards water conservation and provide robust systems in place to harvest rainwater.
Water mismanagement is usually a bigger cause for concern than non-availability of water. For an exciting monologue on how water mismanagement is happening, please refer to this tremendously interesting talk by P. Sainath on water management.