Nar Valley Ornithological Society

The Nar Valley

The River Nar is a tributary of the River Great Ouse. It rises near the village of Mileham and flows 26 miles west through Castle Acre and Narborough (the latter giving the river its name), joining the Ouse at King’s Lynn. In 2011 the Nar was recognised by the Environment Agency as one of the top ten most improved rivers in England and Wales.

A former navigable river as far up as Narborough, it has been used to power a number of mills over the centuries and as a trade route until it ceased to be maintained as such in the mid to late 19th century. The buildings or remains of five mills are still visible. The realignment and diversions of river at these points created ponds and mill races some of which can still be seen today. They create conditions favoured by the Grey Wagtail, the NarVOS emblem, and even the black-bellied form of Dipper has been recorded at Narborough Mill.

The river route

The river rises from springs in the chalk aquifer to the east of Litcham, which create a rapidly-flowing chalk stream initially flowing to the east and then to the south to cross under the B1145 Litcham Road to the west of Mileham. Turning to the west, it passes through the south of Litcham and enters a series of lakes at Lexham Hall. Continuing westwards, the river reaches the lakes of West Lexham Hall. It is joined by a stream flowing northwards from Little Dunham before it crosses under the A1065 and on to Castle Acre.

From here it is wider and starts to form meanders. It passes more lakes at South Acre Hall then crosses Castle Acre Common, and several more lakes in Big Wood. The main channel and a mill bypass both cross a minor road at fords. At West Acre the river passes Narford Lake and to the north of Narborough where there are lakes and a fish farm.

The Nar Valley Way (see below), a long-distance footpath which follows the valley for most of the length of the river now runs along the river bank in a stretch to Pentney Abbey. From here the river is embanked, with flood banks on both sides. Some large lakes at Nar Valley Fisheries are located to the north of the channel, which were formerly a sand and gravel pits as the rather canal like stretch continues under the road from Blackborough End to Wormegay and on beneath Setchey Bridge over the A10. A little to the west, the channel turns to the north reaching South Lynn and the River Great Ouse at a sluice.

The nature of the river

The geology of the upper river consists of chalk covered by a layer of boulder clay making it one of only a few remaining fenland chalk streams and resembling a Hampshire chalk stream. Rainfall is purified as it passes through the chalk, and the spring water, which is crystal clear, alkaline, and always cool, gives the river its rare combination of a chalk stream and fenland river characteristic. This together with its complexities of riffles, pools, gravel beds and meanders, lush bankside vegetation and summer cattle-grazed traditional meadows creates a very rare and nationally important wildlife hotspot.

For this reason, the whole of the river is designated by Natural England as an SSSI (Site of Special Scientific interest), one of only ten chalk streams which have been designated in this way in the United Kingdom.

In 2011 the Nar was recognised by the Environment Agency as one of the top ten (7th) most improved rivers in England and Wales. Historically, the engineering of the channel, to make it straighter, deeper and wider, first for navigation and later for land drainage, took no account of the destruction of habitat which such action causes. Some improvement has been made by setting the flood banks further back from the channel, and creating artificial meanders within the resultant flood plain. Some weirs which inhibit wildlife passage have also been removed where possible. The river provides habitat for sea trout, quite rare in East Anglia, and in addition to the birdlife along the river and valley, its banks are frequented by water voles, otters and up to 12 different species of dragonfly.

There is currently an improvement scheme under way, the River Nar Restoration Strategy, involving the Norfolk Rivers Internal Drainage Board, the Environment Agency, Natural England and local landowners. At Narborough, Castle Acre and West Lexham, diggers are being used to restore natural features such as pools, meanders, and shallow gravel areas in the river channel and reed beds along the banks.

Most of the river is classified as a main river by the Environment Agency, which takes on various responsibilities, especially minimising flood risk. Below Narborough, the river is constrained by flood banks and the water level can be above the level of the surrounding land. A series of drainage channels and pumping stations mitigate the risk of flooding across an area which is primarily agricultural land, including most of the Nar Valley. The catchment that supplies this area is much larger, at 46.89 square miles (121.4 km2), as water flows from the higher ground around its edges.

The Nar Valley Way - Long Distance footpath

There is good access to the River Nar and this is particularly helped by the Nar Valley Way, a route contained almost entirely within the watershed of the River Nar. The walk links with the Peddars Way at Castle Acre. An extension from Gressenhall into East Dereham is included.

Visit the Long Distance Walkers Association web site entry for The Nar Valley Way.