Reference conditions and class boundaries: initial set of guidlines for reference conditions and class boundaries

Abstract

The main purpose of this document is to provide guidance toimproveassessment criteria for individual biological quality elements and to increase harmonisationof methods for establishing reference conditionsand setting class boundaries within and among quality elements.This is done by establishing acommon understanding of important concepts, identifying strengths and weaknesses of current approaches and suggestingways forward towards an efficient and harmonised approach for defining reference conditions and class boundaries.Through discussions, an internal questionnaire and studies of the EU assessment of the Swedish WFD implementation, we identifiedchallengesand potential solutions forissues concerningindividual quality elements and,in terms of the overall coherence,ofassessmentcriteria. Challenges in coastal waters are mainly associated with the definition and quantification of pressure criteria, which cause problems in the definitionand harmonisation of reference conditions or alternative benchmarks. In inland waters challenges are associated with the efficiency and harmonisation of water body typologies and the definitionof type-specific reference values. A general challenge for most biological quality elements in coastal and inland is to account for factors causing natural spatial variability within types as well as individual water bodies.As a result of these analyses we suggest the following priorities and guidelinesfor coming work within WATERS and projects related to the development of new assessment criteria for the WFD in Sweden:

•Perform a systematic assessment and gap-analysis of pressures in coastal waters using existing data sources (measured and / or modelled) according to pressure types defined in annex 4, in order to define pressure criteria for reference conditions or more likely alternative benchmarks.

•Use the newly developed typology for inland waters (or arevised version) as a framework for developing type-specific references and class boundariesfor all quality elements as is currently done for coastal waters.

•Use the proposed framework for modelling to explore the potential for empirical modelling using environmental factors to account for variability due to natural processes and thereby reduce uncertaintyin ecological assessments.

Keywords

reference conditions; lakes; streams; coastal; marine

Published in

WATERS Report
2014, number: 2014:5
Publisher: Swedish Institute for the Marine Environment

SLU Authors

• Johnson, Richard

  • Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences
    

Associated SLU-program

Lakes and watercourses
Eutrophication
Biodiversity
Acidification
Use of FOMA data

UKÄ Subject classification

Ecology

Publication identifier

• ISBN: 978-91-980646-4-3

Permanent link to this page (URI)

https://res.slu.se/id/publ/64316