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WFD Expert Assessment of Flood Management Impacts - FD2609

This research will support the implementation of the Water Framework Directive (WFD) and enable flood and coastal erosion risk management (FCERM) activities to comply with the legal requirements of the WFD. FCERM activities and infrastructure often result in changes to the natural hydromorphological condition of parts of a river, estuary or length of coast in order to perform their prime function and to be effective. The WFD divides rivers, estuaries and coasts into units of management called Water Bodies (WB). The WFD requires that all water bodies should aim to be maintained or restored to at least good ecological status (GES) and for designated Heavily Modified and Artificial water bodies good ecological potential (GEP). For a surface water body to reach or maintain good status the hydromorphological conditions of the water body are not important in themselves, but they must be consistent with the achievement of the relevant biological quality elements. Additionally there is a default objective that they must not be allowed to deteriorate from their current status.

An assessment tool called MIMAS has been developed to enable non experts to screen engineering activities for their likely impact, using these thresholds. If an impact is screened as potentially significant there will be a need for a more robust assessment (e.g. Expert Assessment) to justify any consent and requirements for mitigation measures. To meet these requirements a fully effective method is required to assess impact of FCERM structures and activities on the ecological status so that it can either be avoided, mitigated or accepted. The impacts of existing and potential new structures and activities need to be assessed. The expert assessment framework must also be able to take into account the cumulative effect of multiple existing impacts and complex or non standard morphological changes.

A scientifically robust piece of work is required that identifies and sets out the practical process that would need to be followed to make an effective expert assessment of the impact of FCERM infrastructure and activities on WFD ecological quality of a WB based on the use of information and expert judgement.

The project concluded that there is currently insufficient data on the hydromorphological conditions within each water body to develop a quantitative scoring mechanism to evaluate whether hydromorphological change results in deterioration between ecological status classes. The majority of surface water bodies have been modified in terms of river continuity and morphological structure and/or the hydrological, tidal and sediment regime thus it is not possible to assume morphological response for a given surface water type. In addition, due to the gap in the science base in understanding the relationship between hydromorphological change and consequent impact on biology, it is not possible to define generic pressure impact relationships. This framework provides a process for determining a proportionate level of assessment in a consistent way to assess hydromorphological functioning, the likely changes as a result of FCRM activities and potential ecological impacts.
Project Documents
• Final Report - SID5 : FD2609 Final Report   (127k)
• Technical Summary : FD2609 Technical Summary   (43k)
• TRP - Technical Report : FD2609 Technical Report   (1316k)
Time-Scale and Cost
From: 2007

To: 2008

Cost: £57,506
Contractor / Funded Organisations
Royal Haskoning
Environmental Protection              
Flood and Coastal Defence              
Flood Defence              
Policy Development              
Fields of Study
Flood and Coastal Erosion Risk Management