There is no easy way to have character not run into the water. Probably your best bet is to use paths to guide the character around the water.
Experimenting a bit I was able to get a Cycle to avoid the water when hunting for apples. The way the kode works is to detect when the character hits water and have it turn around and move back from the water and try again. This works best with round lakes.
With a winding river you'll probably stay stuck. The kode looks like this:
Page 1 -- If I run into water while moving toward an apple, switch to page 2.
WHEN See Apple DO Move Toward
WHEN OnWater DO Switch Page2
Page2 -- Immediately stop moving, switch to page 3.
WHEN DO Move Freeze
WHEN DO Switch Page3
Page 3 -- Spin in place 1-2 seconds. For the Cycle this gets him mostly turned around. Then switchto page 4.
WHEN DO Turn Right
WHEN TImer 1Second Random 1Second DO Switch Page4
Page4 -- Move straight ahead for a couple of seconds and then switch back to page 1.
WHEN Timer 2Seconds DO Switch Page1
WHEN DO Move Forward
Note that all the timer values are set for the Cycle's normal speed. If you've changed the speed or are using a different character you might have to tune the values.
Hope this gives you some ideas.