Strategy Area Description

Rivers and streams are linear habitats with flowing water. Small streams combine to form larger flows, rivers, that travel from high to lower ground and eventually the sea. Where they approach the sea, they may be tidal. The effects of salt water mixing with fresh has important effects upon the ecology of a river's lower reaches. In such situations, these may support areas of mudflats and saltmarsh. These habitats are important as wildlife corridors, supporting a diversity of species and harbouring a range of habitats, depending upon the watercourse's geography and location in the catchment.

The strategy area's main rivers, the Wear, Tyne and Derwent, originate on the flat-topped summits of the Pennine Hills. The first two flow through the area, and out to the North Sea; the once industrialised lower reaches of these are now more important for wildlife than for many decades past.

The rivers Tyne and Wear have increasing fish populations comprising both estuarine and migratory species (such as dab, plaice, sea trout and Atlantic salmon), and are important for these, and the species preying upon them. The latter include a range of piscivorous birds and increasing numbers of fish-eating mammals (for example otter, grey and common seal - the latter two often venturing surprisingly long distances up river).

The Tyne and Wear are tidal over much of their lower reaches within the strategy area. In the case of the Tyne, it is tidal along most of the strategy area's northern boundary (at least as far west as Clara Vale), whilst the Wear is tidal to as far west as Fatfield Bridge, perhaps to the bridge that carries the A182 over the Wear.

The valley of the river Derwent is still largely cloaked in woodlands and holds important populations of birds. The river itself supports the typical birds of fast-flowing river habitats, for example dipper, grey wagtail, common sandpiper and goosander. It reaches the river Tyne at Derwenthaugh, in Gateshead and is tidal up to Swalwell Gut.

The river Team, well wooded in its upper reaches and along its feeder streams (for example the Beamish Burn) rises in County Durham. Overlooked by the Angel of the North, it meanders past damp grasslands (for example Lamesley Pastures) and enters the Tyne at Dunston in Gateshead. Its lower reaches were extensively modified in the 1940s to facilitate the development of the Team Valley Trading Estate.

The lowest of the Tyne's southern tributaries is the River Don. This rises to the east of Eighton Banks, Gateshead, where converging agricultural land drains join and flow across the plain between Sunderland and South Tyneside. Flowing largely through South Tyneside, the Don reaches the Tyne at Jarrow, close to the important ecclesiastical church of St. Paul's. This is adjacent to what was once part of a large complex of inter-tidal mudflats at Jarrow Slake. This was in-filled with the spoil from slum clearance work during the mid-1950s. Some of the intertidal habitat remained until the early 1990s, but most of this remnant was lost to development before the turn of the Millennium, and only a tiny fraction now remains.

The water quality of all of the strategy area's rivers, especially in their lower reaches, improved between the early 1980s and 2010s. Their biological water quality remains 'variable' in such areas, but such stretches may still support important species such as water vole, for example, on the River Don in South Tyneside. The current ecological status of all of the area's rivers is considered 'moderate'.

The entire length of the Tyne's estuary is now an important wildlife corridor, hosting otter and migrating Atlantic salmon. Much of this improvement took place courtesy of major capital investment to reduce point-source pollution. The result was closure of sewage outfalls and improved treatment of discharges from sewage treatment works. In some places, such as at Birtley Sewage Treatment Works (adjacent to the River Team in Gateshead), large reedbeds were created during the early 2000s to support the role of combined sewage and mine water treatment. These hugely improved the quality of water discharges into the river Team and provided important new wildlife habitat. Most of these improvements had considerable benefits for wildlife, with riparian species, such as goosander, kingfisher and grey wagtail being particular beneficiaries.

The river valleys also provide natural flight lines for migrating birds. For example, in the autumn, barnacle geese turn into the Tyne estuary and head, via the Tyne Gap, across country to their wintering grounds in south west Scotland.

Angling

Recreational fly fishing occurs on stretches of the Derwent, the westerly reaches of the Tyne and the Wear, where 'runs' of sea trout and Atlantic salmon have increased, dramatically, over the last 50 years. Coarse fishing is practised at many closed waters and along the Tyne and Wear, whilst sea angling is a popular pastime along much of the area's coastal strip.

Wider drainage patterns and hydrology

Away from the main rivers, the strategy area is criss-crossed by a filigree of smaller watercourses, which create an intimate drainage pattern, especially across the agricultural landscape.  The biodiversity of these, and their adjacent areas, is heavily influenced by the surrounding agricultural practices.

Many of the strategy area's once extensive network of small meandering streams have been 'canalised' into ditches along the headlands of fields or the bases of hedgerows, to improve the drainage of the area's relatively poorly draining soils.

From a seasonal perspective, soils tend to be at their wettest in late winter and early spring, drying out through the seasons thereafter. Ground water levels are usually at their lowest in late summer and early autumn.

The quality of riverine habitats in the strategy area are negatively impacted by urban runoff and storm water overflows, all of which leads to downstream pollution. The groundwater quality of the strategy area is, overall, poor. This state results from the collective impacts of disused mine pollution, diffuse pollution from agriculture, saline intrusion (at the coast), and effluent seepage from landfill.

Estuaries

Over centuries, the estuaries of the Tyne and the Wear, which enter the North Sea less than 11 km apart (at South Shields and Sunderland, respectively), have been profoundly impacted by human activities.

Both rivers are tidal far inland and both are macrotidal (that is, they have a tidal range of over 4m). At low tide, in some parts, they exhibit 'ribbons' of variously interconnected mudflats that support huge numbers of invertebrates such as ragworm Nereis and the crustacean Corophium. Some of the best examples of such habitat are within sight of the 'heart of the city' in both Sunderland and urban Gateshead. These mudflats are important for a variety of migrating and wintering wading birds, for example redshank and curlew, and wildfowl for example teal and shelduck.

The Tyne mudflats form a linear complex that constitutes the largest area of such habitat in the Tyne and Wear area. Since the cessation of large scale river dredging in 1991 they are expanding. Nonetheless, this habitat may be under threat to 'coastal squeeze' as sea levels rise. The river Wear has significant areas of mudflat upriver of the Northern Spire Bridge at Deptford and Claxheugh, where important areas of saltmarsh can also be found.

Saltmarsh

Saltmarshes are productive eco-systems and a scarce local habitat; in the strategy area most of them occur inland on the estuarine stretches of the Wear and Tyne.

The largest area of this habitat along both main rivers has been lost to land claim since the commencement of the Industrial Revolution. On both rivers, large areas of fringing land would have once held this habitat but this has largely been infilled for industry for example at Jarrow Slake (South Tyneside). Today, the Tyne and Wear both retain small amounts of saltmarsh, both linearly and at specific locations. Sunderland has a particular local responsibility with good examples at Baron's Quay, Timber Beach and Claxheugh Riverside. Some of these sites have 'colonising salt marsh species', such as glassworts Salicornia spp., which are poorly represented elsewhere.

Other local examples include where the River Don meets the Tyne at Jarrow Slake (South Tyneside). Here there is a part-created pocket of such habitat, with further small sections on the River Team at Dunston and around Dunston Staithes Basin in Gateshead. In such areas can be found common saltmarsh grass, sea arrowgrass, greater and lesser sea spurrey, a variety of orache species and, on the upper edges of 'the marsh', thrift and sea aster.