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Workshop sessions

Topic 2. Legislative/ Management needs.

• Contrast the EU, North American, and other legislative frameworks for river management
• What are the important needs for defining hydromorphic condition in the context of these legislative constraints?

a) Roger Owen, SEPA.

EU environmental policy on management of hydromorphological pressures.

The key policy driver within the EU for the sustainable management and restoration of surface waters is the Water Framework Directive (WFD) which has incorporated the specific requirements of many previous water policies. The main ambitions of WFD are to restore and protect ecological and chemical status; prevent deterioration and manage flood risk. Although the assessment provisions of the Directive are focused on chemical and biological status it also recognises that hydromorphological condition underpins ecological status and specifies a range of relevant quality elements for that purpose.  The Directive requires monitoring programmes to establish the degree of risk from hydromorphological pressures as expressed by the consequent modification of ecological status.  Water bodies at risk of failing to meet status objectives, for reasons including physical modification, must set out a programme of measures to achieve these objectives in River Basin Plans. A key issue is that WFD ecological status classifications are based on the degree of divergence from reference conditions representing a state of no, or very low, pressures. Attempts have been made in the WFD intercalibration process to define reference state, including hydromorphology, by agreeing low pressure thresholds for drivers, pressures and stressors at various catchment scales. Refinement of this reference condition approach used in intercalibration will be undertaken within the EU in the next 3 years.  This will also be informed by parallel work to define European standards for hydromorphological assessment methods. Although the WFD does not specifically require a hydromorphological status classification of rivers, it does strongly imply a need to understand the relationships between ecological status and hydromorphological pressures in order to determine appropriate restoration measures. Providing robust assessments of the ecological impacts of hydromorphological pressures has proved to be a difficult task but is also a great opportunity to develop the underpinning science.  The lack of cost-effective, pragmatic methods has caused the UK to adopt systems which use surrogates for ecological impacts based on expert judgement. There is an urgent need for scientists and end-users to work in partnership to develop better, low-cost tools to enable water managers to assess the ecological effects of hydromorphological pressures and to direct resources more appropriately at restoration measures.

b) Tim Beechie, NOAA, Seattle.

Hydromorphology and legislation: a North American perspective.

Two main pieces of legislation drive the need for defining riverine reference conditions in the United States: the Clean Water Act and the Endangered Species Act. These acts loosely parallel the EU Water Framework and Habitats Directives, with the Clean Water Act and the Water Framework Directive focusing broadly on river health or integrity, while the Endangered Species Act and the Habitats Directive focus on conservation of specific species. Both US Acts require some method of assessing habitat or biological degradation, as well as some means of setting targets for ‘recovery’. The ideal is to define hydromorphological reference conditions in such a way that one can assess environmental degradation by measuring deviations from the reference regime or state. Early definitions of reference condition tended to be static, one-size-fits-all criteria, such as water quality standards or physical habitat standards. Recent measures of reference condition attempt to account for natural dynamics in at least two ways, (1) assessing deviations from historical ‘regimes’ rather than states in evaluating process that drive hydromorphological conditions, and (2) describing maximum daily loads of specific non-point ‘pollutants’ (including sediment) that vary greatly through time. Both types of reference conditions are best identified through holistic, watershed-scale analyses that simultaneously help accomplish the hydromophology-related purposes of both the ESA and CWA.

Topic 3. What do we mean by ‘reference conditions’ in relation to hydromorphology?