River explodes tires

I have been having a problem where the rivers on my map http://www.beamng.com/threads/6870-Glass-View-Mountains, cause the tires to explode when they touch the water, i believe it has something to do with how many nodes the river has because it doesn't happen at the start of the river, only after about 10-15 nodes along it.

 

The problems answer is: You just have to put down the water density

 

i have done that, it should be using the same density as the official maps unless they changed somewhere, but its only half of the rivers doing it, and its the same density right through.

Edit: just checked the official maps and they are now using 1000, but tires still explode at 650 on my map.