The term riparian buffer refers to the vegetation next to a creek. Depending on the size of the stream an appropriate buffer may be 30 ft or more in width. The buffer should include trees, shrubs, grasses and other plants. The plants directly adjacent to the stream are especially important in protecting the streambanks from erosion. Plants further back help control flooding and improve water quality in the stream. The diagram at the left describes the benefits of the different regions in the riparian buffer.
https://www.tn.gov/content/dam/tn/agriculture/documents/forestry/UrbanRiparianBufferHandbook.pdf