Natural features

This sections contains information on natural features recorded in RHS that are not part of the derivation of the 6 indices.  Features include the number of riffles, pools and bars and the extent of trees and related features.  Channel vegetation extent is also recorded in a broad-brush manner as simple, absent/present/extensive indices. Some features may appear and disappear as you scroll between surveys.  This reflects changes in the survey methodology over the years.