The cost of building dams is always underestimated -
There's erosion of the delta that the river has created,
There's fertile soil below the dam that's likely to be looted,
And the tangled mat of forest that has got to be uprooted.
There's the breaking up of cultures with old haunts and habits loss,
There's the education program that just doesn't come across,
And the wasted fruits of progress that are seldom much enjoyed
By expelled subsistence farmers who are urban unemployed.
There's disappointing yield of fish, beyond the first explosion;
There's silting up, and drawing down, and watershed erosion.
Above the dam the water's lost by sheer evaporation;
below, the river scours, and suffers dangerous alteration.
For engineers, however good, are likely to be guilty
of quietly forgetting that a river can be silty,
While the irrigation people too are frequently forgetting
That water poured upon the land is likely to be wetting.
The the water in the lake, and what the lake releases,
Is crawling with infected snails and water-born diseases.
There's a hideous locust breeding ground when water level's low,
And a million ecological facts we really do not know.
There are benefits, of course, which may be countable, but which
Have a tendency to fall into the pockets of the rich,
While the costs are apt to fall upon the shoulders of the poor.
So cost-benefit analysis is nearly always sure,
To justify the building of a solid concrete fact,
While the Ecological Truth is left behind in the Abstract.
-- This phoem of the economist Kenneth Boulding is reproduced in Malcolm Newson's Land, Water and Development (1992), pages 174-175.