Southampton Water is classified as a heavily modified water body (HMWB) under the Water Framework Directive. Such water bodies are unlikely to reach good ecological status due to socio-economic uses. To review how to maximise the Ecological Potential of Southampton Water, the Environment Agency developed an Opportunity Mapping project; this began with the establishment of a database, based on aerial photography, that mapped coastal structures throughout Southampton Water where mitigation (removal, remediation, or in situ ecological enhancement) measures could potentially take place.
The Solent Forum ran a consultation, with Southampton Water stakeholders, to get their view on how how we could potentially develop mitigation measures for the identified infrastructure and review some of the opportunities and barriers to in achieving this. The findings have now been published - Opportunity Mapping in Southampton Water - Final Report.
All the structures identified from the aerial photography were mapped in GIS and an aerial image of each was drawn. The two maps of Southampton Water (north and south) along with the images can be viewed at: www.solentforum.org/services/Current_Projects/oppmap/Consultation/. The structure types (see table below) were broken down into the three river catchments covered by Southampton Water; Test and Itchen, New Forest and East Hampshire. The Hamble river was used as a pilot for this project and the structures on the river were already consulted on so were not included in the consultation.
|Seawalls||Tyres||Jetties||Concrete blocks/pipes/outfalls||Wooden posts/structures|
|Metal wrecks||Plastic wrecks||Wooden wrecks||Concrete slipways||Revetments|
|Rip Rap Walls||Moorings/pontoons||Quay walls|
The Environment Agency also mapped the Southampton Water habitats to identify what the underlying habitats are for the identified structures.
The Solent Forum was contracted by the Environment Agency to consult on the structures identified. It was undertaken in three phases:
Once this consultation finished, a revised list was drawn up; in the future this list could be used as a basis for ground-truthing and consultation with landowners. Eventually it is hoped that we can identify potential structures for mitigation for developers, local authorities, port and harbour authorities and the EA’s Flood and Coastal Erosion Risk Management who need to undertake mitigation measures for Water Framework Directive Assessments as part of proposed works or development.
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.
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 https://environment.data.gov.uk/catchment-planning/OperationalCatchment/3419.
A glossary of terms used in river basin management planning is available at https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/496499/RBMP_Glossary.pdf.
The Environment Agency measures whether a HMWB meets its Ecological Potential or not by:
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.