1 (13) Earith to Needingworth via Bluntisham – published
Download Walk Guide below
2 (14) Needingworth to St Ives via Holywell – being developed
3 Additional walk into Ouse Fen, RSPB nature reserve
4 & 5 Additional walks from St Ives to Godmanchester (and Huntingdon) and back to St Ives
For a key to the geology see the British Geological Survey map viewer.
The first walk heads upriver to Needingworth, via Bluntisham, and the second walk continues on, via Holywell to the historic town of St Ives. Although the main Trail then heads south to Fenstanton, an optional extension takes you further upstream through one of themost attractive sections of the river, via Houghton to Godmanchester and the extensive, and very biodiverse, Portholme Meadow. A short further walk takes you into the town of Huntingdon. The return walk takes you back along the south side of the river via the Wildlife Trust’s Godmanchester Nature Reserve and the Hemingfords. The RSPB is developing a large area of disused gravel pits for wildlife conservation, Ouse Fen, which can be visited as a detour from the first walk.
The geology of the valley has been important economically due to the large amounts of sands and gravel that were deposited in a series of River Terraces at various times in the last half a million or so years when glacial meltwater formed much larger and stronger rivers through the valley. Some of the excavated areas are now mostly flooded and are being developed as wetland areas for wildlife conservation. For more information on the formation and geology of the valley see the website of the Cambridgeshire Geological Society.
‘My favourite thing about this walk is that you can imagine being near the coast here 3,400 years ago, looking out over tidal creeks, with saltmarsh stretching into the distance’
The route: ‘into the valley of the River Great Ouse‘
5.3 miles (8.5 km) Walking guide time 2.5 hours minimum plus stops
Having arrived at Earith, at the southern end of the Ouse Washes, the Trail turns south west to Bluntisham and Needingworth. Most of the walk is only a few metres above Mean Sea Level reaching a maximum of 21m. At several points it crosses the 5m contour, the approximate fen edge. Partly following the River Great Ouse, the walk takes you through a gentle landscape that does not resemble the large, ’Ice Age’, braided river that formed the lower part of the valley as it reached the fenland basin. Extensive research by Cambridge Archaeological Unit has revealed many significant cultural sites showing that people adapted to changing water levels over the last few thousand years, in a dynamic delta-like landscape. The furthest extent of the sea incursion c.3,400 years ago, during the Bronze Age, saw marine conditions extend to just south of Earith and waterways were possibly tidal much further inland. The Ouse Valley has always been an important travel route and the walk joins up with several long distance footpaths – the Ouse Valley Way, Rothschild Way, Greenwich Meridian Trail and the Pathfinder and Via Beata Long Distance Walks. The land adjacent to the river, all below 5m, has extensive gravel workings, much of which are now wetland again, forming the reedbeds and open water of the RSPB Ouse Fen Nature Reserve.
Landscape and Geology
The local bedrock is Ampthill Clay. It dates from the Jurassic period about 160 million years ago when ‘mud’ on the floor of a shallow sea became compressed enough to form a sticky and relatively soft rock. This is now overlain by much younger deposits, from the Pleistocene ‘Ice Age’, the oldest being Glacial Till (Boulder Clay), material left by glaciers during the Anglian glaciation (c.425,000 years ago). There are also substantial amounts of sand and gravel deposited by powerful Glacial Rivers of meltwater which flowed during subsequent glaciations. In the last few thousand years (the Holocene), Peat formed on top of the gravels when (fresh) waterlogging lasted long enough for the build up of this organic material. It is at the surface in places but mostly it is covered by river Alluvium, up to 2m deep and extending over hundreds of hectares in this area. This walk starts on the river Alluvium, at 5m above sea level, passes across the 1st/2nd River Terrace gravels going as high as 21m just on the edge of the Glacial Till in the centre of Bluntisham. It then crosses the Ampthill Clay on the way down to another patch of 1st/2nd Terrace gravels before returning to Alluvium and levels as low as 2m by the river. It finishes at 15m on the 3rd Terrace at Needingworth.
Geology map from Map leaflet
© Cambridgeshire Geological Society