Sunday, 17 January 2010

The 'upper' Upper Kennet

Above Swallowhead Springs the River Kennet is fed by seasonal winterbournes that are usually dry for long stretches during the Summer and Autumn, but which can swell in the winter and spring to a significant enough level to merit their inclusion on Environment Agency mapping of flood warning areas.

The most northerly point where public access enables you to view the latent Kennet is from the A4361 at Gadbourne Bridge, south of Swindon and NNE of the village of Uffcott at SU 122 782, but, unless you like looking at ditches and small culverts, it's not the most exciting spot.

The water in this image at Gadbourne Bridge is just a residual puddle, as the winterbourne below this point was dry down to and beyond Uffcott in late October 2009.

Flowing to the east of Uffcott, the Kennet stream stores itself as a pond at the bottom of the village (SU 124 774), which, when sufficiently charged, escapes over a stone slab and travels south.  Another pond at The Weir (Su 113 769), just to the West of Broad Hinton village, acts as a similar small seasonally releasing reservoir, and the two channels meet where they are crossed by the White Horse Trail at SU 115 761.

The pond at Uffcott...

and the pond at The Weir.

Still appearing to be somewhat of a small agricultural ditch, and clearly having been alligned as such over the years, this winterborne flows under the minor road between Broad Hinton and Hackpen Hill, and the A3461, before passing through the eastern edge of Winterbourne Bassett.  Taking the road into the village from A3461 the Kennet can be viewed from the bridge at SU 102 749, just before the White Horse Inn.

Upstream from the Bridge at Winterboune Bassett in January 2010.

Downstream from the bridge at Winterbourne Bassett in October 2009,...

...and in January 2010.

At the western edge of Winterbourne Bassett another small stream rises and flows south to join the main channel below the village near the site of the medieval village of Richardson.  A public footpath crosses the stream at the back of Rabson Manor (at SU 097 745), but after this the next view of the Kennet is at the hamlet of Berwick Bassett.  From the road bridge at SU 099 733 the cyclical nature of a winterbourne can be clearly seen.

Downstream from the bridge at Winterbourne Bassett in late October 2009,... mid-December 2009,...

...and in mid-January 2010.

The water levels occasionally get much higher and when talking to a resident in January 2010 he expressed some interest in whether water levels were "backing up".

In flood conditions the water level may rise up across the grassed area to the road in front of the houses.

Following the left fork of the road at Berwick Bassett to SU 097 371 a public footpath runs alongside the right bank of the river for most of its journey down to Winterbourne Monkton.  At the northern end of this village the winterbourne once again demonstrates its flow variability, but this time with the aid of a measuring gauge.

Upstream of the bridge at SU 098 724 in late-October 2009,... mid-December 2009,...

...and mid-January 2010.

Downstream of the bridge at SU 098 724 in late-October 2009,... mid-December 2009,...

...and mid-January 2010.

The public footpath continues running south through Winterborne Monkton, although not quite on he bank of the river, until it reaches the road to the church in the southern half of the village at SU 098 718.  There is also an off-shoot public footpath across the river at SU 098 720.

The river continues southwards, travelling to the west of Avebury Manor, where it is joined by another winterbourne tributary that flows from small collective catchment area NE of Yatesbury, which is itself to the NE of Avebury.  The joined streams flow between the villages of Avebury and Avebury Trusloe, crossed by the A4361 at New Bridge (just past the Avebury visitor car park) at SU 099 695.  From here a public footpath travels alongside the left bank of the Kennet almost all the way to Pan Bridge, where the river flows under the A4 by Silbury Hill and across  field to Swallowhead Springs.  Just before Pan Bridge, the river is joined by a third smaller winterbourne that flows from Beckhampton, and around the northern edge of Silbury Hill to a confluence at SU 102 684. 

It is possible to walk along the dry bed of the nascent River Kennet to the east of Silbury Hill at certain times of the year, in this case October 2009.


You can even walk right under the A4 at Pan Bridge during dry periods (Oct. '09).

Fortunately, the river will reappear rapidly after the water table is sufficiently replenished - upstream from Pan Bridge in January 2010.