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The River Hamble Harbour Authority

Habitats and their protection

The River Hamble has a wealth of interesting environmental features that include food rich mudflats, a wide variety of wildfowl, fish nursery areas, saltmarsh that acts as a natural coastal defence and even historic ship wrecks.

The River is part of the Solent Estuarine system which is particularly noted for its national and international importance as a habitat for breeding and migratory birds. It is fascinating to see which birds will chose the Hamble as their home for the winter months. If it weren’t for food and shelter that the river provides these birds would no longer be seen here.

The main habitats found in the extensive inter-tidal areas include; 125 hectares of mudflats, 60 hectares of salt marsh and 60 hectares of coastal grazing marsh. At the mouth of the river there is a saline lagoon which is internationally designated. The Hamble offers some of the best examples of mature saltmarsh on the south coast.

The mudflat and saltmarsh habitats are important for wildfowl and wading birds, as well as for molluscs, crustacea and annelids. The water vole, the otter and important species of beetles, moths and invertebrates can also be found in the river’s habitats.

Nature Conservation Areas

The River Hamble has a number of areas which are recognised as important sites for nature conservation. These designations are made because of particular habitats, species or numbers of a particular species found within the designated area.

Official monitoring and reporting on the status of designated sites is undertaken by Natural England (NE). Maps, the monitoring results, any required actions and those bodies responsible for these are available at Nature on the Map. A map showing site boundaries can also be found on the Hamble Estuary Partnership website.

Site of Special Scientific Interest (SSSI)

Lee-on-the-Solent to Itchen Estuary SSSI

A component of this SSSI includes several sections of the River Hamble. These sections are recognised as being Internationally Important for over-wintering dark-bellied brent geese. Nationally Important for teal, wigeon, dunlin & ringed plover. Additionally there is cord grass saltmarsh, as well as a high population of benthic invertebrates including species of mollusc, crustacea & marine worms. Low water intertidal muds provide major feeding grounds for waders and dark-bellied brent geese.

Lincegrove and Hackett's Marsh SSSI

Structurally this area is one of the best examples of mature saltmarsh on the south coast. Dominated by sea purslane, common cord grass, saltmarsh grass, sea lavender, thrift, sea aster & sea club rush, as well as providing feeding grounds & high water roosts for waders and geese.

Upper Hamble Estuary and Woods SSSI

Site includes woodland community species of ancient semi-natural woodland. With gradation from ancient semi-natural woodland to estuarine saltmarsh which is a nationally rare feature. The saltmarsh is particularly dominated by species such as sea couch grass, sea club rush, sea arrow grass, sea purslane & thrift. The mudland also supports large populations of marine worms, crustacea & molluscs. Consequently provide feeding grounds for several other species of birds including waders and ducks.

Special Protection Area

Solent and Southampton Water SPA

Designated as important because it is regularly used by the following species:

Ramsar Site

Solent and Southampton Water - Wetland Of International Importance (Ramsar site)

Similarly to the SPA this has been designated because it regularly supports 20,000 waterfowl, and significant numbers of the following species.

Special Area of Conservation

Solent Maritime SAC

The sections of the River that are included within the SAC are principally designated for the saltmarsh incl. cord grass & mudflats. These areas provide extensive feeding areas for birds, in addition to being home to a significant assemblage of invertebrate, crustacea and molluscs. Due to the extended tidal stands in the Solent there is greater feeding time for many of the species concerned. This designation is also there to protect the form and function of the Hamble as an estuary.

What effect do these designations have?

In the case of SSSIs there are certain operations listed for each site which cannot take place without permission from Natural England, or the consent of another public body such as the Harbour Authority (provided that the other body has formally consulted Natural England). Natural England will consider the application and give a decision as to whether the operation can take place or whether it is prohibited or may be undertaken within certain restrictions.

In respect of SPA and SAC sites a single management scheme exists - The Solent European Marine Sites scheme (SEMS). This covers all SPA and SAC sites in the Solent and there is not a separate scheme specifically for the sites in the Hamble.  The SEMS scheme includes a set of conservation objectives and a favorable condition table for the site, provided by Natural England. The management scheme considers all activities which take place within and adjacent to the SAC or SPA and assesses whether or not they will have an adverse effect on the site, and whether any form of control or prohibition is required. Any new projects or developments require separate consideration. In these circumstances, Natural England advise decision making bodies as to whether the proposal is likely to have a significant effect on the features of the designated site.  The Ramsar sites are very similar to SPAs in terms of locations and species, and also the way they are considered.

In-combination Effects

Decision makers (such as the River Hamble Harbour Board) have a statutory duty to asses whether a plan or project is likely to have a significant effect on a SAC or SPA, either alone or in-combination with other planned or proposed developments. Natural England provides advice to assist this process. The in-combination aspect recognises that an operation that by itself may have no significant effect but if undertaken many times or in combination with other operations/projects may cause a deterioration to the features for which the site is designated.

If the decision making body determines that the project may result in a significant effect then an Appropriate Assessment must be carried out.  The Harbour Authority (or other lead decision-making body such as the Local Planning Authority or Marine Management Organisation) may only permit the proposals if the Appropriate Assessment concludes that there would be no adverse effect on the integrity of the SAC/SPA site. Where it cannot reach this conclusion, the project can then only proceed in particular circumstances. This process allows those proposals which clearly will not impact upon the special features of the site to proceed. Natural England is able to provide advice to authorities on how proposed activities can avoid adverse impacts on a SAC.

Acceptable Limits

When considering the effect of an operation on a designated site it is likely that some change to the designated site is inevitable. This change must be considered as to whether it is acceptable in terms of the designated features and falls within acceptable limits.


River Hamble

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