Mean and 95% Cl for 483 semi-natural River Habitat Survey (RHS) sites across the UK. Small steams (Strahler (1957) stream order 1 and 2), are characterised by, a) the steepest slopes (%), b) relatively few sediment storage features (bars) per unit length of channel (no/500 m), c) smallest bankfull channel widths (metres) and, d) highest substratum diversity within the river network (Shannon diversity index). Original Data from the Environment Agency, RHS database.