water plug-in:can’t place foliage under river

[baobao4435]

hello,all.
I can’t place foliages under a river,why?
but I can place them under a lake.
Which parameter should I adjust so that I can place rocks under a river like lake do?

Here’s a video indicating the issue:

left side is a lake and right side is a river.
what should I do?
im new to this plugin .thank you.

[baobao4435]

got it!
for anyone who wants to know how to place foliages under a river.
the solution:

1:turn off the river’s collision at selection mode.

2:enter foliage mode.then you can put foliages under the water.

3:back to selection mode.turn collision back on.