To tackle the problem of fast depleting groundwater tables, Indian Concrete Institute, Chennai, has suggested that cement roads can be designed to allow water percolation. Such roads are made up of three layers. Each layer is 80 mm thick, below which is a 200 mm thick pavement slab and at the bottom lies a 350 mm cement stabilised soil.

Is it a viable strategy? We asked this question to DSrinivasan, secretary-general of ICI.

Q: Is this technique costly?
A: No. Only the composition of materials used for constructing the ordinary roads, needs to be altered.

Q: What is the permeability rate?
A: Varies with rainfall and soil type.

Q: Many areas in Chennai have clay soil. Will this technique work in these areas as well?
A: One cannot even build ordinary roads on clay soil.

Although, this experiment has been successful in Japan, in India it is still at an experimental stage.

Plumbers’ meet

On August 4, about 15 plumbers participated in a meeting organised by the Tamil Nadu unit of National Water Harvester’s Network, CSE and Akash Ganga Trust, a Chennai-based non-governmental organisation.

While welcoming the participants , CSE staffer explained the objective of this meet and the role of the rain centre in providing information. Only one participant had practical experience of rainwater harvesting. The three hours of interactive session cleared many of their doubts. The group came out with interesting suggestions like, using stoneware pipes for interconnection to reduce the cost. This meet was another step in strengthening rainwater harvesting, at the local level.