1. Definition and Establishment of Reference Conditions
Roger Owen, Willie Duncan, Peter Pollard
Outline of major issues for REFCOND guidance
Evaluation of questionnaire data
Definition of Reference Conditions
Establishing the values representing Reference Conditions
Dealing with variability of values within type-specific Reference Conditions

2. Outline of major issues for REFCOND guidance
1. Definition of Reference Condition
do we need a more precise or more practical definition?

3. Outline of major issues for REFCOND guidance
2. Establishing values representing Reference Condition
what benchmark should we use to determine undisturbed condition?
what is meant by minimally disturbed?
does any modification of a water body disqualify it as reference?
how do we deal with “other significant pressures”?
what methods should be used to establish reference condition?
should we update reference condition values eg.climate change?

4. Outline of major issues for REFCOND guidance
3. Dealing with the variability of values within type-specific Reference Conditions?
how much natural variation can be accommodated within types?
how can we predict different biological reference values from the same physical and chemical variables within types?
how can we avoid the problem of large numbers of types to be able to detect impacts?

5. Evaluation of current practice in Europe
Information used:
REFCOND questionnaire returns
EU project guidance and recommendations
EurAqua
AQEM
CEN: recent standards
Other WFD interpretation papers

6. Evaluation: relevant issues
are WFD quality elements already used in classification schemes in Europe?
are national and international standard methods used?
are current methods WFD compliant?
do current methods employ reference conditions?
which approaches and methods are used to set reference conditions?

8. Evaluation: Use of Quality Elements in River Classification
all except phytoplankton in use
benthic invertebrates, nutrients, oxygen, pH/ANC, non-synthetic pollutants most used (10 member states)
macrophytes, phytobenthos, fish, hydromorphology least used (4-5 member states)
national/international standard methods in use reflect current classification methodologies …… but status?
WFD compliant methods claimed for all except phytoplankton and fish age-structure …….but
further information required to judge compliance

9. Evaluation: Current approaches to setting Reference Conditions in rivers

10. Evaluation: Approaches used to set reference conditions in Rivers
all optional approaches used in Europe
Spatial Network methods
Expert Judgement methods
Historical Data methods
Predictive Modelling 40 methods
Palaeoecology methods

12. Evaluation: Use of Quality Elements in Lake Classification
all biological and physico-chemical quality elements in use in Europe
nutrients; pH/ANC most commonly used (12; 8 member states)
phytoplankton, macrophytes, benthic inverts fairly commonly used (5 - 7 member states)
few hydro-morphological elements in use
national/international standard methods in use reflect current classification methodologies …… but status?
WFD compliant methods claimed for all except phytobenthos and hydromorphological elements

13. Evaluation: Use of different approaches to setting Reference Conditions in lakes

14. Evaluation: Approaches used to set reference conditions in Lakes
all optional approaches used in Europe
Spatial Networks methods
Expert Judgement methods
Historical Data methods
Palaeoecology methods
Predictive Modelling 28 methods

15. Evaluation: Criteria used to set Reference Condition at selected sites

16. Evaluation: Conclusions on REFCOND data
majority of WFD quality elements being used already across Europe but no Member State is using all of them
a small number of current methods are claimed as WFD compliant
a number of current classification methods claim to establish reference conditions …..but
uncertainty about precise criteria used to set reference conditions, including “minimally impacted”

17. Options for Suggested Approaches
1. Definition of Reference Conditions
Definition 1: Directive derived
“ For any surface water body type Reference Condition is where there are no, or only very minor, changes to the values of the ...quality elements which would be found in the absence of anthropogenic disturbance. The following criteria should be met:
the values of ... quality elements should correspond to totally, or nearly totally undisturbed conditions.
specific synthetic pollutants should have concentrations close to zero or at least below the limits of detection….
specific non-synthetic pollutants should have cocentrations remaining within the range normally associated with undisturbed conditions.”

18. 1. Definition of Reference Conditions
Definition 2: EurAqua STR8
Reference condition is:
“A situation with hydromorphological and physicochemical regime sustaining a healthy ecosystem functioning with natural biodiversity”

19. 1. Definition of Reference Conditions
Definition 3. CEN standard (Biological classification using benthic macroinvertebrates in rivers)
“… data from a site (the observed data) should be compared with a set of reference data. The reference data represent the expected natural community that would be found at the site, when only natural stresses are present and man-made stresses are absent or considered to be insignificant”

20. 1. Definition of Reference Conditions
Recommendation:
The definition of Reference Condition should be as precise as possible and follow the terminology of the Directive. The guidance document should provide further interpretation and assistance.
Stick with Definition 1!

21. 2. Establishing Values Representing Reference Condition
Main questions:
what benchmark to use to determine undisturbed condition?
what is “minimally disturbed” condition?
what about “other significant pressures”?
what approaches should be used to establish reference condition values?
what criteria should methods for determining quality element values be judged by?

22. 2. Establishing Reference Condition Values
Guidance required: how to set limit values on quality elements to include “nearly totally undisturbed”
Suggested process:
Set criteria for minimally disturbed state
Use flexible benchmarks - dependent on pressure
Set criteria against which to test quality element measuring tools

23. Minimally Disturbed: Concept
High Status
Criteria for Acceptable Pressure State?
UNDISTURBED
MINIMALLY DISTURBED
SLIGHT DISTURBANCE
Good Status

24. 2. Establishing Values Representing Reference Condition
Recommendation:
Develop a matrix of criteria for REFCOND guidance which provides the degree of acceptable change in an anthropogenic pressure that would provide the limits for sites at “reference condition”.

25. Type of pressure Examples Indirect pressures on supporting conditions
Land-use effects such as diffuse pollution; run-off rates
Airborne inputs such as acid rain
Climate change effects
Indirect pressures on supporting conditions
Point discharges to water;
Abstractions;
Impoundments
Other direct morphological changes
Direct pressures on supporting conditions
Direct pressures on biological quality elements
Resource exploitation (e.g. fishing);
Vegetation clearance;
Introductions of alien species

26. Reference condition criteria
1. Indirect pressures on supporting conditions
Pressure
Criteria defining very minor disturbance
Land-use change
Impacts compatible with pressures pre-dating any recent land-use intensification
Airborne inputs
Impacts compatible with pressures pre-dating any recent intensification in airborne inputs
Climate change
As airborne inputs above? Or update reference conditions so effects are ignored?
Example:
Impacts resulting sea level rise or increased drought frequency would be unacceptable. Therefore, managed retreat & some reductions in abstraction during drought would be justified to achieve good status
Example:
Impacts resulting from inputs of acid gases associated with industrialisation would be unacceptable. A level of control over acid emissions would be required to achieve good status
Example:
Impacts resulting from net nutrient imports into a river basin would be unacceptable. Therefore, some controls over diffuse pollution would be justified to achieve good status

27. Reference condition criteria
2. Direct pressures on supporting conditions
Pressure
Criteria defining very minor disturbance
Morphological alterations
Impacts compatible with past modifications to which the biological, chemical and hydromorphological systems have been able to adapt and recover a level of diversity and function similar to comparable unmodified systems.
Example:
Persistent synthetic substances are likely to be present in many EU waters. However, where their presence does not have an environmental significance, it would be environmentally arbitrary to consider them.
Example:
Some river engineering over the last few centuries may have changed the river from one ‘stable’ hydromorphological state to another. Today such systems are difficult to distinguish from unaltered rivers.
Abstraction/ impoundment
Variability of the flow regime is not affected but there may be minor reductions in the flow levels
Example:
Although the biological relevance of flow reductions is not well established, proportionately small reductions in flow would not be expected to cause direct or indirect stress on biota.
Point source discharges
No discharges of synthetic substances liable to increase existing concentrations, and the existing concentrations are less than the EQSs

28. Reference condition criteria
3. Direct pressures on biological elements
Pressure
Criteria defining very minor disturbance
Species introductions
Established species not causing further ecological displacement of the native flora and fauna can be regarded as naturalised - an acceptable impact.
Alien species should be disregarded as a pressure unless they are of ecological significance to the native flora and fauna.
The loss of a species is unacceptable. Species abundance shows some disturbance but only causing a very minor change in the overall recruitment.
Age class structure of fish show some signs of disturbance but there is not a failure in the reproduction or development of a species.
Over-fishing

29. Establishing Reference Condition Values
Spatial network? Modelling? Historical data? Palaeoecology?
Recommendation:
An heirarchical decision process should be established to assist in the selection of approach used for setting reference conditions.

30. Suggested approaches for determining reference conditions
Conceptual Model of Method
Expert view
Validated Working Methods
Test and Refine Model
Reference condition values

31. Determining reference conditions
Availability of data for water body type
Suggested Approach
Spatial network + predictive model
Yes
Minimally impacted sites available?
Minimally impacted sites available elsewhere? No
Borrow data and use in spatial network + predictive model
Yes
Historical data? No
Predictive model eg.palaeoecology; hindcasting
Yes
No relevant sites or data? No
Expert judgement model concept and test when data become available
Yes

32. 2. Establishing Reference Condition Values
Criteria for evaluating quality element tools
Can it predict values at reference condition?
Can it provide a robust statistical probability of class status?
Will it assist with the risk assessment of pressure-impact (good stress-biological response relationship?)
Does data already exist?
Is it already well-established and validated?
How resource-demanding is it ?
……………………………...

33. 3. Dealing with variability of values at Reference Condition
how much natural variability can be accommodated within types?
how can we differentiate between natural variation and impact?

34. 3. Dealing with variability of values at Reference Condition
Type 295
Natural biological variability
High natural variability may lead to large numbers of types to narrow range of values in order to detect impacts

35. 3. Dealing with variability of values at Reference Condition
If site specific reference conditions can be defined for each quality element the need to identify large numbers of water body types to accurately predict the values of quality elements can be circumvented.
Recommendation:
Within any water body type it is permissable to define site-specific reference conditions for each quality element

36. Using physico-chemical/hydromorphological factors to predict biological quality elements in a water body
Different sets of factors necessary to predict reference conditions at different sites

37. 3. Dealing with variability of values at Reference Condition
Site-specific reference conditions for different biological quality elements are likely to be determined by different sets of physical and chemical factors
this approach implies that multiple site-specific reference conditions are allowable within any one water body type
Recommendation:
For any water body type it is permissable to use different sets of chemical and physical factots to determine the reference conditions for each quality element.