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

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

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?

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?

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

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?

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

Evaluation: Current approaches to setting Reference Conditions in rivers

Evaluation: Approaches used to set reference conditions in Rivers all optional approaches used in Europe Spatial Network 147 methods Expert Judgement 87 methods Historical Data 75 methods Predictive Modelling 40 methods Palaeoecology 12 methods

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

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

Evaluation: Approaches used to set reference conditions in Lakes all optional approaches used in Europe Spatial Networks 95 methods Expert Judgement 93 methods Historical Data 58 methods Palaeoecology 39 methods Predictive Modelling 28 methods

Evaluation: Criteria used to set Reference Condition at selected sites

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”

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.”

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”

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”

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!

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?

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

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

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”.

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

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

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

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

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.

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

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

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 ? ……………………………...

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?

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

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

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

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.