Why Can't Washington State get it togther?

The Washington State Army Corp. of Engineers control water levels on the states largest body of water, Lake Washington.  yet with annual flooding from rivers across the state, we seem to have problems with damages year after year. Am I iggorant about how this could be? or can there be things done statewide to fix this annual problem.

I can't bear to see all the lost business, homes, personal effects caused by the flooding in these areas, This in turn adversly affects real estate and the economy.

China is building the world's largest dam at Three Gorges that will stop flooding. How can we accomplish the same goals?