Extending riverfly Extending riverfly monitoringmonitoring

Richard Chadd,Richard Chadd,Senior Environmental Senior Environmental

Monitoring Officer,Monitoring Officer,Environment Agency Environment Agency

(Lincolnshire and (Lincolnshire and Northamptonshire Area)Northamptonshire Area)

The old approach – water qualityThe old approach – water quality

• Started in the 1960sStarted in the 1960s• From 1990 onwards, From 1990 onwards,

regular reporting to regular reporting to government (‘colours on government (‘colours on maps’), NRA then EAmaps’), NRA then EA

• 1995 – 2005: General 1995 – 2005: General Quality Assessment Quality Assessment (GQA)(GQA)

• Trend very much Trend very much upward, so now rather upward, so now rather old newsold news

Different stresses Different stresses • Drought & abstraction Drought & abstraction

pressurepressure• Leads to development of Leads to development of

Lotic-invertebrate Index for Lotic-invertebrate Index for Flow Evaluation (LIFE) in 1999Flow Evaluation (LIFE) in 1999

• British invertebrates placed British invertebrates placed in one of six flow-groups in one of six flow-groups based on velocity preferencebased on velocity preference

• Final index is derived from Final index is derived from taxa in these groups & taxa in these groups & adjusted by relative adjusted by relative abundanceabundance

Different stresses (2)Different stresses (2)• Sediment accumulation (tillage, Sediment accumulation (tillage,

livestock poaching, urban livestock poaching, urban runoff)runoff)

• Metric for this - Proportion of Metric for this - Proportion of Sediment-sensitive Sediment-sensitive Invertebrates (PSI)Invertebrates (PSI)

• Derives an abundance-Derives an abundance-weighted ratio of sediment-weighted ratio of sediment-sensitive to sediment-tolerant sensitive to sediment-tolerant taxa (output = 0 to 100)taxa (output = 0 to 100)

• EU Water Framework Directive EU Water Framework Directive will require other stressors to will require other stressors to be assessed and classifiedbe assessed and classified

HydroEcological Validation (HEV): River HydroEcological Validation (HEV): River Nene (Duston Mill, NorthamptonNene (Duston Mill, Northampton))

Score reduces with Score reduces with rising abundance of rising abundance of fine sediment & low fine sediment & low flow indicators and flow indicators and rises with sediment rises with sediment & flow-sensitive & flow-sensitive taxa.taxa.

May try 1, -1, -2, -3, May try 1, -1, -2, -3, as presence of these as presence of these indicators in low indicators in low abundance indicates abundance indicates a ‘healthy’ state.a ‘healthy’ state.

Original 8-taxon list Original 8-taxon list still operates.still operates.