The Water Festival marks the annual flow reversal of the Tonle Sap River!
There is a river of four 2-sided cards that gets “randomly” laid. By random, they may be rotated and shuffled, but laid in such a way that they create a horizontal line between players. Play starts and continues as normal, but players will play off the river to start their landscape. Each section of the river has a feature and if players have a majority of that particular feature in the connected paddy at the end of each season, they will earn a scoring ability. When playing with The Water Festival, the Wet Season has a set intermediate scoring. Before the Dry Season they’re all flipped over and have a more randomized scoring for the end of the game.
—description from the publisher