Dependent on the Cauvery for its waters and the Raichur thermal power plant for its energy and a vast hinterland for its food requirements, how can Bengaluru become resilient to water, energy and food demands and shortages?
Here are some things going for the city which can reduce these demands. Suppose we imagine the city with 40 sq. m. of land for every resident. As we have a human right to water which can arguably be 50 litres per person per day and a right to lifeline energy of say 1 unit per person per day, suppose we had a right to land too and this right we can imagine it as 40 square metres per person.
With this land, a person could dig a basement or a cellar for a house and excavate enough earth for constructing the walls for his home. Stabilised earth blocks made on site using stabilised earth mortar reduce the need for sand and thus help save rivers. Roofs can be made of these earth blocks too.
Rainwater falling on the rooftop can be harvested. With an average rainfall of 900 mm in a year, 40 square metres can harvest 36,000 litres of water. If this water is stored or recharged into the aquifer then it can provide 100 litres per person per day equivalent. Enough for normal consumption. This will provide water security.
If solar panels are placed on this 40 square metre, it can generate 20 units of electricity. Enough for one citizen with a surplus to export to the grid. This will provide energy security.
With the enthusiasm of terrace gardening in the city and the experience developed, 40 square metres of terrace garden can provide a substantial portion of the vegetable and grain requirement of the individual. This will provide food security.
The waste stream generated by a person such as from the kitchen, the bathroom and the toilet need space to be absorbed. 40 sq.m of land can absorb all the greywater, the composted kitchen waste and even the black water waste from twin pit toilets completely, thus becoming a self-contained unit. This will provide non-pollution security.
By growing plants and crops and say by planting two trees each, the bio-diversity of the place can be enhanced, thus providing ecological security to all matters of life such as birds, bees and butterflies.
Imagining poly-nodal cities, with self-contained townships of 200,000 to 500,000 people connected with mass transport through a hub-and-spoke model; and imagining cities which are productive of the material needed for their construction, for their water and energy needs and the ability to absorb waste streams is crucial to India’s urban challenge.
Different imaginations are needed and that would be ecological and water wisdom.