4 Is a functioning floodplain present? 

 Does your stream overflow its banks every few 

 years? If not, the stream may be changing because of 

 alterations in the watershed. Without a floodplain, the 

 stream's energy is concentrated in the channel during flood 

 flows. This increased energy may either downcut the channel 

 or erode the banks. 



To determine the edge of the bankfull channel, which is the 

 beginning of the floodplain, look for: 



• top of point bar 



• change in 

 vegetation 



• slope break 



• change in 

 particle size 

 of bank 

 material 



• undercuts in 

 the bank 



• stain lines 

 or lower 

 extent of 

 lichens on 

 boulders 



Downcut stream 

 with no floodplain 





All of these 

 characteristics 

 influence the 

 personality of your 

 stream under natural 

 conditions. Stream 

 types may be changed 

 by our alterations and 

 activities. 



Stream with functioning 

 floodplain 



5 



What is the channel shape? Channel shape is mostly influenced by: 



• quantity of water • amount and type of vegetation 



• amount and size of sediment and its associated root mass 



• type of bank and bed material * human activities that directly 



, „ , alter channel or watershed 



• gradient/valley slope 



wsBSSm Mfli KMH 



Common channel shapes 



