Photo Of The Day

Image: Ueslei Marcelino/Reuters A worker is seen inside the Cuncas II tunnel that will link the canals being built to divert water from the Sao Francisco river for use in four drought-plagued states, a project that is three years behind schedule and has doubled in cost from the original estimate of $3.4 billion, near the city of Mauriti, Ceara state, Brazil, Jan. 28, 2014.

Image: Ueslei Marcelino/Reuters
A worker is seen inside the Cuncas II tunnel that will link the canals being built to divert water from the Sao Francisco river for use in four drought-plagued states, a project that is three years behind schedule and has doubled in cost from the original estimate of $3.4 billion, near the city of Mauriti, Ceara state, Brazil, Jan. 28, 2014.

Darkness at the End of Brazil’s Great Water Tunnel

When complete, this tunnel – it is a tunnel carved by humans, not water – will be more than 4 kilometres long. The Cuncas II tunnel is part of an ambitious 477 Kilometre network of tunnels and canals that is being built to provide north-eastern Brazil with water. The region has a long history of droughts, and it is currently experiencing its worst in half a century.

The government’s solution is to divert water from the mighty São Francisco River. Originating in the south-east and flowing for nearly 3000 kilometres through much of the country, the São Francisco is known as “the river of national integration”. But it turns to the ocean before it reaches north-east Brazil. This means the four states of Ceará, Paraíba, Rio Grande do Norte and Pernambuco are left parched. Diverting some of the river’s flow could give the region a major boost.

Yet relief from the drought is unlikely to come any time soon. The government’s biggest infrastructure venture is only half completed. It isn’t technical problems that are slowing progress; it is bureaucracy and red tape. The cost of the plan has doubled from its original estimate, to $3.4 billion.

The government says water will start to flow to the north-eastern states by 2015.

New Scientist

 


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  • Hedgehog

    How come other countries can dig tunnels and irrigate drought stricken states and we’d be at it for years before a spade touched the ground?

  • caochladh

    Whatever happened to the project to complete a canal between the Manukau and the Waitemata?

  • peterwn

    There is a trade-off between pre-tunneling work and the predictability of tunneling cost. Geologists and engineers do what they can but there is always the possibility of surprises. In Auckland the Vector tunnel project would have yielded valuable information on soil/ rock conditions which would provide some greater degree of certainty of costs for the proposed rail tunnels.

    An interesting feature of the Brazil tunnel it its roughness. Presumably a larger rough tunnel is more economic to build to do than a smaller smooth tunnel. Roughness does reduce flow capacity for a particular tunnel size. Meridian considered it economic to build a second Manapouri tailrace tunnel to reduce the head losses of the water exiting the turbines and flowing through the tunnels to Doubtful Sound. There was a partial constriction in the first tunnel which engineers thought would erode away but it never did. This was another case where the construction of the first tunnel provided excellent geological information to plan and cost the second tunnel. If there were significant cost over-runs on the second tunnel heads would have rolled in no uncertain terms. Incidentally the second tunnel (unlike the first one) was completed with no fatalities.

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