I am just starting to mess with vim adventures and have come to the water. I cannot figure out how to jump it. So far I have passed the treasure chest because I read that you need something from Level 3 to get it and I have picked up nothing but the key that got me through to the water area.
Normally in vim, if you're at the end of a row and you move up or down to a shorter row, you will move to the end of the shorter row. If you then continue to move up or down to a row that is as long as (or longer than) the original row, you will move to your original column position in that row.
This is explained to you by the girl with the pink hair in the grassy section.
The solution is thus:
move yourself to the far left of the topmost grassy row (indicated by the red arrow, above)
juntil you reach the bottom row. You will appear just to the right of the one-way ramp (where the blue arrow points).
You will need to make use of this behavior several more times to fully navigate the grassy section.