Dredging for more
Can infrastructure be sustainably built in a developing economy? As India undergoes a developmental period, this question assumes importance. Infrastructure growth is likely in railways, roads, airports, smart cities, large industrial units, super technological communication systems and the like. One of the major factors in infrastructure development is civil construction. In this sand, soils, cement, aggregate, and steel are forerunners.
With shrinking utility services, the requirements of legal environmental restrictions and advocacy and desirability of sustainability, the cost of construction is steadily rising. To overcome the above situation, it is possible to use the huge amount of dredged material from various ports. At the moment, this material is dumped in the sea.
Every year, ports such as Kolkata, Paradip, Visakhapatnam, and Chennai on the east coast of India produce millions of tonnes of dredged material. A similar situation also exists on the west coast.
Dredging is essential for navigation, remediation and flood management of waterways Use of dredged material can reduce the quantities of primary resource needed for activities such as construction and habitat creation. Some countries do already make extensive use of dredged material. In Japan, more than 90 percent of dredged material was used in the past.
In India, a new capital city of Andhra Pradesh is coming up at Amaravati. An area covering 30 villages between Vijayawada and Guntur, some 35 km away from Amaravati town has been marked for capital development.
Pitched as a world-class riverfront capital city, Amaravati will be an energy-efficient and green city with a concentration on industrial hubs. The Andhra Pradesh government, through the Capital Region Development Authority, has acquired some 30,000 acres of land. Expected to be completed by 2018-19, the Seed Capital Area (SCA) of 16.7 sq.km. will be home to about 300,000 residents. The business hub is expected to generate about 700,000 jobs in various sectors, including government.
There will be a thriving, state-of-the- art Central Business District (CBD) for business and living.
The master plan envisages nodes and corridors for a transit-oriented development approach. So, there will be an integrated network of 12 km of Metro railway, 15 km of Bus Rapid Transit system, seven km of downtown roads, 26 km of arterial and sub-arterial roads and 53 km of collector roads.
The plan for the capital city has huge potential for infrastructure, civil engineering, and construction activity.
It is possible that the dredged material from the ports on the east coast could be easily used at Amaravati. Depending upon properties of dredge material, it could be used for brick-making. Initially, some trials may be required for this purpose, but once it is found to be useful, it would be the most sustainable process for development.
The dredged material could also be used for several other purposes such as landfill caps and covers, beach nourishment, topsoil creation and enhancement, habitat creation or restoration, reclaiming of mined land and parks as well as in agriculture, forestry, aquaculture, and horticulture. If the dredged material is sold to the Amaravati Capital Project, it would generate a huge business. The capital project is planned to be developed in three stages and over 10 years. Financially, that would be highly beneficial to all dredging companies and also to Andhra government which could use the material for sustainable development. There’s a historical example of such sustainable development happening.
In the sixties of last century, laboratory experiments were conducted to find out whether fly ash waste from thermal plants could serve as a partial replacement for cement. After successful trials, researchers came to the conclusion that fly ash could be used in making concrete. At present, about one-third of fly ash replaces cement in making concrete.
There is no reason why dredging material cannot do what fly ash did for the construction industry.
(Arun Bapat is a research seismologist formerly at Central Water & Power Research Station, Pune.
The views expressed are strictly personal.)