Water from an underground lake within a Savanna lake creates three waterfalls and flood a cave entrance. Note: Pointless channels are no more as of V1.1.1
1.0.0 - A tall Mountain waterfall heads to the river
1.0.0 - A Mountain spring creates two waterfalls into the river
The waters from a hill spring have eroded a creek down the hill in a forest
1.0.0 - Two Plains lakes flow to the sea
A three level Gravel->Sand generator can convert all that spare gravel you've mined into useful sand
An eroded creek curves through the forest
1.0.0 - A creek flows through a Big Tree Taiga
This entire creek system would not exist in the stock game. It would just be the small lake at the top of the hill.