The Lower Bann River drains 38% (4500 square kilometres) of the catchment of Northern Ireland and part of the Republic of Ireland. At approximately 60m wide for most of its 60 kilometre length, it is considered to be a large river in the context of Ireland. The Lower Bann River leaves Lough Neagh at Toome, widens at Lough Beg and in the Estuary before it enters the Atlantic to the north between Portstewart and Castlerock.
As well as being vital for drainage, the Lower Bann River and hinterland are important in terms of the natural and built heritage and local economy and for amenity value. The river corridor is rich in wildlife, with Lough Beg and the Estuary being particularly important for breeding and passage birds. The Lower Bann River itself provides a conduit for migrating eels and salmon and a habitat for coarse fish species. The River is navigable from the sea to Lough Neagh with various water based activities, such as cruising, canoeing, water skiing etc. taking place along its length. The Lower Bann also provides a focus for land based recreational activity including walking and cycling.
The Lower Bann River leaves Lough Neagh at Toome and enters the sea 60 kilometres to the north between Portstewart and Castlerock. In an Irish context it is a large river; it is about 60 metres wide along most of its length with wider stretches at Lough Beg and the Bann Estuary. The overall gradient of the river is modest - it drops from 12.55 metres above sea level from Lough Neagh to its mouth.
Lough Beg is essentially a widening of the Lower Bann, 3 kilometres downstream of Toomebridge. It has an area of approximately 5 square kilometres and apart from the deeper navigation channel the lake is generally about 2 metres deep. The spire of the church on Church Island stands out as a landmark above the low woodland in a deeply tranquil and remote wetland fringe landscape. In this area the valley floor is wide and flat with areas of cut-over bog and extensive flat pastures merging into shallow drumlins.
The Kilrea glaciofluvial complex extends from Portglenone to the Vow (downstream from Movanagher). These steep sided sand and gravel hills and ridges are very distinctive with well-wooded slopes.
From the Vow to Ballylagan (downstream from Drumaheglis) the valley floor widens and flattens where there was a former lake at the confluence of the Agivey, Aghadowey, Macosquin and Ballymoney rivers. Here low-lying fields are criss-crossed by a network of straight drainage ditches. Many of the fields have been enlarged to form extensive open flat pastures with a scanty hedgerow network although close to the Bann there are areas with a small scale field pattern.
From Ballylagan to Coleraine town the valley narrows with steep well-wooded sides contrasting markedly with the upstream section.
From Coleraine to the sea the river is a tidal estuary. Downstream from the town, where the estuary begins to widen, there are extensive sand dunes on both banks. The estuary is long and narrow with limited mud flat development on the seaward side.
The Lower Bann river runs through 5 local authority areas; Coleraine, Ballymoney, Ballymena, Antrim and Magherafelt. The main settlements close to the Lower Bann River are Toome, Portglenone, Kilrea and Coleraine.
From the Cutts weir to the sea for a distance of 11 kilometres the Lower Bann is tidal. The outer estuary is not large (it has a maximum width of 0.5 kilometres). The Coleraine urban section of the estuary supports some reedswamp and woodland fringe but, as the channel further widens in the middle part of the estuary, larger reedswamps appear. There are areas of mudflat and marsh and sand dune systems on both the Castlerock and Portstewart sides with older dunes at Grangemore, near Articlave. Coleraine Harbour is less commercially active than it once was but a dredged channel for boats entering and leaving the harbour is still maintained between the breakwaters at the Barmouth. The estuary is used by commercial boats, for angling, watersports, walking, etc.
The Bann Estuary is important for birds especially wintering waders and wildfowl that mostly feed on the mudflats and roost on the shore. The estuary usually supports about 4000 birds each winter. Its local importance is highlighted by the success of the birdwatching hide at the railway crossing but it is clearly important in a wider context as it is part of a Lower Bann migration flyway. Each spring and autumn large numbers of birds on their way to and from countries further north pass through the Lower Bann corridor linking to either Lough Neagh or wetlands and coastal areas further south in Ireland or even mainland Europe.
The sand dunes at Portstewart and Grangemouth are managed as National Trust nature reserves. The National Trust also leases the shooting rights from The Honourable The Irish Society over the mudflats to manage these as a no-shooting wildfowl refuge. The North Derry Area of Outstanding Natural Beauty extends to the west side of the Bann Estuary. The Bann Estuary is an Area of Special Scientific Interest and proposed Special Area of Conservation.
Apart from the deeper navigation channel most of Lough Beg is about 2 metres deep. Drainage schemes on the Lower Bann have inadvertently benefited the Lough Beg marginal habitats in that lowered water levels have helped to create an area of wet grassland on the former lake bed one thousand acres in extent on the west shore - an area known locally as ‘The Strand’. This land is grazed but has not otherwise been agriculturally improved. The wet grassland is largely flooded in winter providing habitat for wintering wildfowl and as the winter floods recede it supports large numbers of breeding waders (redshank, lapwing, curlew, snipe and occasionally dunlin).
In spring and autumn Lough Beg is an important staging post for migrating birds to rest and feed on their way through. The Strand is rich in plant species including a remarkable number of rarities most notably Irish Lady’s Tresses (Spiranthes spiralis), Northern reed grass (Calamagrostis stricta) and Penny Royal (Mentha pulegium). All of Lough Beg with its marginal habitats is protected as an Area of Special Scientific Interest, a Special Protection Area and a Ramsar Site.
Recreation pressure at Lough Beg is low as boats are confined to the deeper navigation channel and access to the lake shore is difficult. There is some wildfowling and birdwatching.