Josh Bean

In the current version of the game (1.22.2) this is wrong. A drop in elevation will set total length to 6 (including the block it drops on). So it'll flow for 5 blocks before you need to drop a level. I think you included the -1 to the height difference because you thought you needed use the height the rapids started after the first drop. This is true, but you also "gain" a level because the last run doesn't require a drop, so it evens out. The corrected equation simplifies to: L = 6 + (h)*5 Note that this gives you the distance that the rapids will travel starting at the source block coordinates and ending at the last flow length of the final run (ie, the block you usually drop down at). If you start with a rapids at 0, 150, 0 and you want the rapids at y = 148 the max distance is 16 blocks. This is just considering the rapids travel distance. If you want to power your water wheel at max power, then use a destination height positioned above the expected water wheel location.