Characterisation

Characterisation of water bodies is a critical element of the work required under the Water Framework Directive. It sets the scene for where the water resources are and how they function in the landscape, and provides the understanding of how they are impacted by the pressures caused by human activities. The outcome of characterisation is the identification of water bodies at risk of not meeting their WFD objectives. Article 5 of the WFD, supported by Annex II which contains some of the required detail, identifies three components in the characterisation of water bodies:

  1. an analysis of its physical characteristics, i.e., the physical information that describes the water
    bodies including water body boundaries, typologies, reference conditions, the geology and
    hydrogeology of groundwater bodies including the nature of the overlying strata, linked
    groundwater and surface water systems, etc.
  2. a review of the impact of human activity on the status of surface waters and groundwater, and
  3. an economic analysis of water use.

Programmes of measures are implemented in those water bodies identified as being at risk, and monitoring programmes are designed to assess whether the measures are effective. The characterisation process is therefore a major driver in designing appropriate monitoring networks and implementing measures. Measures have to be cost effective so the economic analyses, as well as other factors such as the beneficial uses of the water resources, help to prioritise the measures. The effectiveness of the measures is checked using the monitoring data, incorporating various metrics such as status, trends and capacity
assessments, which are then fed back into the next characterisation cycle. Figure 1 provides a summary of the process.

Characterisation in the WFD Framework

Figure 1: Characterisation in the WFD Framework‌

Characterisation Approach and River Basin Mangement Plans

Nationally, we are required to deliver a River Basin Management Plan in 2017. To do this, we must first characterise our water bodies. This allows us to then develop mitigation measures targeted at restoring and/or protecting our water bodies that are at risk of not being at good status. There are three steps in the characterisation process:

  1. Preliminary Risk Screening: a risk assessment of the status of water bodies, trends based on monitoring data and existing measures. This tier identifies water bodies ‘At Risk’ of not achieving good status. The results will be published in the Significant Water Management Issues (SWMI) Report.
  2. Initial Characterisation: allows the ‘At Risk’ water bodies to be further investigated. This tier focuses on small catchments to determine which pollution sources have the greatest impact on water bodies by identifying likely significant pressures such as point sources and critical source areas for diffuse pollution.
  3. Further Characterisation: is targeted at the significant pressures, such as critical source areas for example, and involves undertaking catchment walks and monitoring to get an understanding of how these sources of pollution can be better managed.

The characterisation process informs the selection of the programme of measures. The involvement and cooperation of local communities, local authorities, and government/public bodies will be essential to ensure that the measures implemented are successful in improving our water resources.

Learn more:

You can find out more in An approach to characterisation as part of implementation of the Water Framework Directive (May 2015)