can some1 plesae tell me why braided channels are a problem to river navigation?

Answer 1

Braided channels are those that tend to be rocky (with small rocks) and shallow. They are called braided because the river follows many channels at once and it looks like the "braid" back and forth.

The reason they pose an issue is that the river spreads out to the various channels. this causes two thing: 1, the river must get shallower in order to provide water to all these channels and 2, it is often very difficult to determine which channel has enough water to navigate. A third dilemma is that in the winter and spring when there is a lot of water flow, the rocks that make up the braiding will often shift, so even if there was a channel through one braid one year, it may not be the same the next year.