WFD Classification Explained

Appendix X

WFD Classification explained

There are two classification systems for the waterbodies within the Water Framework Directive; one for Natural waterbodies and one for Heavily Modified waterbodies (HMWBs). There are over 30 different measures tested for classification purposes and they are split into biological measure, water quality measures and mitigation measures (HMWBs only).

Natural waterbodies.

This classification system is the simplest of the two. It works on a one out all out basis. This means that as soon as any one of the measures used to determine the overall ecological status of the waterbodies falls under good status, it affects the whole waterbody and drops the status.

Examples (based on biological measures only):

Fish Bad Macrophytes Moderate Overall status Bad Invertebrates Moderate Diatoms Good

The above example is at bad status as the fish are driving down the classification.

Fish Good Macrophytes Moderate Overall status Poor Invertebrates Moderate Diatoms Poor

The above example is at poor status as the diatoms are driving down the classification.

Heavily Modified waterbodies (HMWBs).

This is the more complex system.

Initially, three measures must be discounted from the classification of HMWBs. These are fish, macrophytes (aquatic plants) and invertebrates. This is because these three measures are highly sensitive to physical changes in waterbodies. These physical changes are often referred to as morphological changes and the three biological measures above are said to be morphologically sensitive.

The only biological measure that can be taken into consideration is diatoms. These are microscopic algae that indicate the ecological health of rivers. They are not morphologically sensitive and have a direct link to nutrient enrichment (and phosphates in particular). Mitigation measure assessments must be carried out on all HMWBs to see whether the measures identified to mitigate the affect of the physical change have been put in place. There are only two classification levels for mitigation measures. If they are all in place then the mitigation measures are at good status and if they are not all in place then the classification for mitigation measures is moderate status.

Availability of water (flow) in a waterbody is also very important when classifying HMWBs. If there is not enough water available (flow fails), then any one of the biological measures including those that are sensitive to changes in morphology can cause a waterbody to have a worsened status. This is shown clearly in the last example below.

Examples:

Mitigation Measures Good Fish Bad Macrophytes Moderate Overall status Good Invertebrates Moderate Diatoms Good Flow Pass

The above example is at good status as the fish, macrophytes and invertebrates are not included in the classification.

Mitigation Measures Moderate Fish Bad Macrophytes Good Overall status Moderate Invertebrates Good Diatoms No data Flow No data

The above example is at moderate status as there is no data on diatoms and flow and the mitigation measures are at moderate (i.e. not all in place). Again the fish, macrophytes and invertebrates are not included in the classification.

Mitigation Measures Moderate Fish Good Macrophytes Moderate Overall status Bad Invertebrates Bad Diatoms Poor Flow Fail

The above example is at bad status as there is a flow failure. This is the only time in a Heavily Modified Waterbody that the morphologically sensitive biology are taken into consideration when classifying. Current classification data for the LocalLEE river waterbodies. s ? e r d u s s m e s i s e o e f e t i 0 a t a h i h a t d 1 y e n r p

C n o h w h

o b x M O e H s m o p 8 P i e M e WB Code WB name Ecological status l b m p t e

D o n n F r F r o x y T o t l n m e c i e i t y v a A A n v a h n n a I M g P i e A t i H M 2009 N/A 2010 GB106038027950 Y Lee Navigation Subsiduary A 2011 C 2009 C C C C C U 2010 C C C U C C GB106038077852 Y Lee (From Tottenham Locks to Tideway) 2011 C C C C U C C C 2009 C C C 2010 C C C GB106038077851 Y Lee (From Woolens Brook to Tottenham Locks) 2011 C C C C 2009 C C C C C N/A 2010 C GB106038027940 Y Pymmes Brook (Upper Channel) 2011 C C C C C 2009 C C C U C C 2010 C C C C U C C U GB106038027960 Y Salmons Brook 2011 C C C U U C C 2009 C C N/A 2010 C C GB106038033180 Y Cuffley Brook to Turkey Brook 2011 C 2009 C C N/A 2010 C C C GB106038033190 Cobbins Brook 2011 C C C C 2009 N/A 2010 U GB106038033200 Y Small River Lee & Tribs 2011 U C 2009 U N/A 2010 C GB106038033210 Nazeing Brook 2011 C 2009 U N/A 2010 C C C C GB106038027910 Y Pymmes Brook (Salmons Brook to Lee) 2011 C C U C 2009 U N/A 2010 C GB106038027920 Y Moselle Brook 2011 2009 C C C C C 2010 GB106038027930 Y Ching Brook 2011 Key

Ecological Status No data Moderate Data Certainty Biological Status Bad Good U - Uncertain Chemical Status (including Annex 8) Poor High C - Certain Annex 10 Status/flow N/A Good Moderate Fail