11.   But the ice dam was structurally weak.

12.   But the dams are at no more than one-third capacity, officials say, straining demands for rural irrigation and urban water supplies.

13.   By the fifteenth year, the dam will be free to sell all its power to the highest bidder.

14.   Critics say the dams are needed for agriculture, flood control and electricity generation.

15.   Dams always have been essential to hydropower because the turbines that produce the electricity require an extremely forceful, confined flow of water to work.

16.   Ecologists say the dam will be a disaster.

17.   For all these reasons, ecologists say dams are a major reason why rivers and streams are generally becoming biologically poorer, even as they get cleaner.

18.   For Beijing, the dam is a matter of national pride.

19.   For fall chinook, virtually everyone agrees, dam breaching would be a boon.

20.   For Republicans, the dam is also fraught with risk.