Hyderabad: Relaying of 1,800 km of city roads prior to the GHMC elections was done with concrete, but without any modern technology or ideas being used.
In the Netherlands, the roads are constructed with material that absorbs rainwater, which allows for recharging of groundwater. In Hyderabad, after a single downpour there is water logging on roads but no change in groundwater levels.
The cost per kilometre is almost the same. Several areas, like Habsiguda, have been declared dry as there is zero groundwater.
Experts hold GHMC responsible for not applying such techniques or working on water harvesting pits.
Prof. N.V. Ramana Rao of JNTU’s civil engineering department said, “This technology is called ‘pervious concrete roads’ in which there are open pores on the road surface. Whenever it rains, the road absorbs water and this recharges the groundwater level. Indian roads are normally made of solid blocks. The pervious concrete road technology is currently used in Delhi. Some apartments and gated communities have laid these roads.”
“Pervious roads are also designed to take the traffic load. It is a mixture of ‘aggregate’ – small broken pieces of stone and a special grade of cement —when water flows on it, it gets absorbed into the ground below. Foreign nations spend around $80,000 (about Rs 54 lakh) on one km of this road. “In India, going by present calculations, it will cost around Rs 60 lakh per km of pervious concrete road,” said Mr Rao.
“There are two advantages with this technology. Rainwater is absorbed into the ground. So roads do not break down and have a longer life. Rainwater directly seeps through the pores in the road and joins the groundwater, slowly resulting in the rise of groundwater levels,” said Prof. G.K. Viswanadh of civil engineering at JNTUH.
A senior engineer from GHMC said, “The amount spent on 1 km of road is Rs 10 lakh to Rs 50 lakh keeping in mind the past condition of the roads. In case of a concrete cement road, almost Rs 50 lakh is spent per km.
“While experts suggest alternative ways, the GHMC in association with residents’ welfare associations should encourage people to lay pervious concrete roads within colonies on partnership bases, with 70 per cent of the cost paid by GHMC. Secondly, it should construct rainwater harvesting pits free of cost in every colony.”