Appendix 3: RQI

Riparian Quality Index calculation

The Riparian Quality Index (RQI) represents the complexity, naturalness and continuity of the riparian zone The riparian zone is defined as the zone comprising the bank face, bank top and a buffer from 5m of the bank top assessed as part of the River Habitat Survey (RHS).

The RQI features three sub-scores for complexity, naturalness and continuity that are calculated separately for each bank and added to yield a final site score between 0 and 120.  The final RQI is classed into five equal quintiles to represent increasing riparian quality from ‘Very Low’ (1st quintile) to ‘Very High’ quality (Last quintile).

Complexity sub-score (maximum: 60)

Score each bank separately. For each spot-check, score the bank face and bank top vegetation structure using the following table and add the scores for both banks.

Naturalness sub-score (maximum: 40)

Score each bank separately. For each spot-check:

• score 1 if the bank material is natural and no modifications were recorded.
• score 1 if the 5m land use is natural

Add the scores for both banks

Continuity sub-score (maximum: 20)

Score each bank separately. Count the number of spot-checks with simple or complex vegetation structure on the bankface OR on the banktop that are contiguous.  Add the scores for both banks.

Examples: Left bank vegetation structure B = Bare; U = Uniform; S = Simple; C = Complex. In grey are highlighted valid scoring spot-checks.