The Solent Forum

Working in parnership for the future

Opportunity Mapping on Southampton Water Shoreline

Water Framework Directive and River Basin Plans

The purpose of the Water Framework Directive is to establish a framework for the protection of inland surface waters, estuaries, coastal waters and groundwater. The framework for delivering it is through River Basin Management Planning. The Solent lies within the South East Basin River District.

River Basin Management Plans set out the environmental objectives for the river basin district, with a summary of the programme of measures that will be taken to achieve them; the achievement of the objectives is measured against the Ecological Status or Ecological Potential of the water body.

Water Bodies

Each River Basin District is characterised into smaller management units known as Water Bodies. The Water Body for this project is the transitional and coastal waters (TraC) of Southampton Water. A transitional water is a surface water in the vicinity of river mouths which are partly saline in character as a result of their proximity to coastal waters but are substantially influenced by freshwater flows. Transitional waters include estuaries and saline lagoons.

A map of the operational catchment for Southampton Water is available to view at

A glossary of terms used in river basin management planning is available at

Achieving Good Ecological Potential

Southampton Water is a heavily modified water body (HMWB); these water bodies are unlikely to reach good Ecological Status due to socio-economic uses. The aim is to maximise the Ecological Potential of the site. The Environment Agency measures whether a HMWB meets its Ecological Potential or not by:

  1. Identifying the impacts affecting the water body
  2. Identifying the mitigation measures necessary to ensure the hydromorphological characteristics of a water body are consistent with Good Ecological Potential; and
  3. Assessing whether those measures have been taken.

This project seeks to fulfil the second objective above, identifying mitigation measures. Hydromorphological characteristics are the physical character and water content of water bodies. Good hydromorphological conditions support aquatic ecosystems such as water flow, and substrates provide physical habitat for biota such as fish, invertebrates and aquatic organisms.

Identifying Mitigation Measures to Achieve Good Ecological Potential

The Environment Agency has put together a database, from aerial photography, for identifying opportunities throughout Southampton Water where mitigation (removal, restoration, or ecological enhancement) measures could take place. The Hamble river was used as a pilot and the database has been mapped for this location and has gone through the first stage of stakeholder verification.

The Environment Agency has also mapped the Southampton Water habitats to identify what the underlying habitats are for the identified structures.

The Solent Forum has been tasked with consulting with a range of local stakeholders on the identified opportunities to check their viability for mitigation measures, in the parts of Southampton Water outside of the Hamble Estuary. Once this consultation has taken place, a revised list will be made available for ground-truthing and consultation with landowners. Eventually this list will be released to developers, local authorities, port and harbour authorities and FCERM who need to undertake mitigation measures for Water Framework Directive Assessments as part of proposed works and/or development.

Southampton Water Catchment Consultations

For the purpose of this project, Southampton Water has been broken down into four areas that reflect the river catchments that drain in to it. Each section will be individually consulted with relevant local stakeholders. 

1. River Hamble

Consultation complete, revised list published. The next stage is for the revised list to be ground-truthed and landowners confirmed.

2. East Hampshire
3. Test and Itchen
4. New Forest Coast