My physics teacher once narrated a tale of how politicians were misleading villagers by telling them 'remove power from the water', hence crops would not grow properly.
The politician was supposedly referring to the electricity generated upstream, hence 'power removed', there would be 'lesser power' left for the crops to grow.
So, my teacher said, villagers must be given proper information about dams and how generating electricity does not remove any actual 'power' from the water, and that scrupulous politicians were using the situation to rail against the dam.
However, in my opinion, the politicians were inadvertently right, and my teacher was wrong: putting up dams does actually remove 'power' or 'punch' from the water - silt and hence nutrients are held back - which could lead to lower crop yield. I have no idea which dam he was talking about and dams have varied locations and maintenance; so silt accumulation may or may not be a major problem, but in many dams this has been a problem(wiki, Aswan dam, 1, 2, KRS Mysore, Mettur dam).
To sum up, politician makes a seemingly inaccurate statement to further his goals; they could be ultimately true albeit in a different sense.