Adjust cost of levees and water gates

With the addition of bad tides and the anti-cheese for water dumps the early game i feel the cost is too high for these items in the early game as you are priority is going to be food, water, and prepping for a bad tide

Levees could use a lower unlock price and a drop is log cost (maybe from 12 to 10?)
Flood gates are essentially a required item for dealing with a bad tide and they could use a drop in unlock price, at least for a small one