Each player tries to erode their mountain and generate the most amount of sediment in their delta. Players erode their mountains with the processes they successfully bid on and acquire. The sediment supplied to the delta becomes the coinage used in the bidding process. Mountains uplift 1,500 meters per turn until one player reaches 8,000 meters, or until the "Active Uplift Shutdown" event card is drawn. Then, it's a race to see who can erode their mountain away the fastest. When a player successfully erodes their mountain, the game ends. The winner is the player with the most sediment in their delta, after subtracting any sediment that remains in their mountain.
To the play the game, you need to print out a copy of the rules, the bidding row, the game cards (the card types include event, process, mountain front, and mountain type), and enough game boards for the number of players that will play. A cool rock and a cup to hold the sediment is also needed. You will also need to buy a couple boxes of Jujubees (you can eat them while you play), as they are the "sediment" used in the game.
The designer recommended printing the game materials (except the rules) in color, on 11" x 17" cardstock. To make the game, the designer recommended using a paper cutter, a glue stick, scissors (for minor clean up), and scotch tape.
The "Erosion" v. 1.0 ZIP file was available for download as of May 9, 2008 at the designer's former webpage
The files have been unavailable since Sierra Madre Games announced that they were publishing a revised version of Erosion in 2009.