Rejuvenation. Changing Channel characteristsics. Width and depth are simple variables and generally increase downstream as more water is added from tributaries. Width can be derived either from the water surface width (occupied channel width) or from measuring from bank to bank, giving the bank full width. We can calculate the stream order from source to mouth too, and this gives us an indication of the size and shape of river channels. The stream order is calculated as follows; Stream order 1 streams have NO tributaries feeding into them, they are the original streams that start at springs up in the source. Stream order 2 streams occur where two stream order 1 rivers come together at a confluence Stream order 3 streams occur where two stream order 2 rivers come together at a confluence (not a stream order 2 with a 1, it must be the SAME stream order meeting) The stream order continues like this. Wetted Perimeter is the measure of how much water contact there is with the bed and the banks of a river.
Source. Formation of a delta. Formation of a delta. BBC -The course of the River Severn - from source to sea. BBC How is a river formed - streams, tributaries and confluences. Rejuvenation. Flowing water.