DEVELOPMENT OF ENVIRONMENTAL STANDARDS
(WATER RESOURCES)

STAGE 1 REPORT: IDENTIFICATION OF HYDRO-MORPHOLOGICAL PARAMETERS TO WHICH THE AQUATIC ECOSYSTEM IS SENSITIVE

WFD48 Stage 1
March 2005

EXECUTIVE SUMMARY

Background to research

This project arises as part of a coordinated effort by the UK environmental agencies to prepare for implementation of the Water Framework Directive – specifically in relation to water resources regulation.  Its overall aim is to develop methods for the establishment of regulatory standards for rivers and lakes.  The project excludes Heavily Modified Water Bodies.

Objectives of research

This is a Stage 1 report based on review of the international literature in order to identify all hydro-morphological parameters which affect aquatic ecosystems – either being used by water users/regulators around the world or identified within the research literature.  It includes a gap analysis to report on parameters which have not been adopted in reported studies or practices, but which may merit consideration in the UK.  It provides a focus for discussion between members of the project steering group and the contractors, and a sense of direction for future stages of the project.

Key findings and recommendations
The main outcome of Stage 1 was that the regulatory parameter for environmental standards for rivers at a broad scale should be flow, since data on potentially more ecological meaningful parameters such as depth and velocity are not widely monitored and cannot be determined with detailed surveys at all sites.  Since flow varies greatly between water bodies, generic flow standards need to be expressed in dimensionless terms, such as proportions of natural flow or unit flow per drainage area or channel width. Nevertheless, UK agencies should develop a hierarchical approach to standards, where broad scales methods based on flow are used for screening, but detailed scale methods based on more directly ecologically meaningful parameters, such as depth and velocity, are used for site level impact assessment and license setting.

For lakes, water level is the key hydromorphological parameter because of its integrative role in relation to the volume and dynamics of flow (including residence time) and its relative simplicity of measurement.  The relative ease of measurement however belies the paucity of existing long-term data in relation to natural regimes of lakes across the UK.

Key words: abstraction, flow release, hydrological regime, timing, magnitude, duration, frequency, hydro-morphology, parameters, standards, rivers, lakes.

Copies of this report are available from the Foundation, in electronic format on CDRom at 20.00 + VAT or hard copy at 25.00, less 20% to FWR members.

N.B. The report is available for download from the SNIFFER Website