Environmental Engineering Reference
In-Depth Information
west of the town of Ripon and whose ruins and visitor centre are a World Heritage site,
held extensive grazing rights in Upper Wharfedale to support the abbey's wool
production. The agricultural improvements of Britain in the eighteenth and nineteenth
centuries AD had little effect on this remote dale.
The two land uses which have had most impact on hydrology and soil erosion since
1800 have been lead mining and moorland improvement through drainage. Coarse
sediments in terraces and alluvial channels in Wharfedale have been correlated with
mining activities in the nineteenth and early twentieth centuries by analysing their heavy
metal content (Howard and Macklin 1998). Moorland drainage for purposes of improving
grazing or afforestation since the mid-twentieth century is achieved by 'gripping'. Upland
peat bogs normally slow down the release of precipitation by a 'sponge effect'. When
drained by 'gripping', however, there are better soils for plants, but soils which have
lower interception capacities and depression storage. The lag times of stream run-off
peaks are reduced, and flood peaks and the movement of sediment are enhanced (Stewart
and Lance 1983).
Upper Wharfedale is shown in the oblique air photo of Colour Plate 1 (below), taken
in winter. Grass Woods, a remnant of the original deciduous woodland cover, is seen in
the immediate foreground. The gorge of Conistone Dib and the village of Conistone are
in the centre, and Kilnsey Crag is centre left in the photo. Prominent limestone scars are
seen in the centre right of the image. The mouths of the glacial valleys of Littondale and
Langstrothdale are clearly visible in the upper left. Upper Wharfedale can also be seen on
the centre-right margin of the satellite image of Colour Plate 2 between pp. 272 and 273.
The underlying structure of the horizontally bedded rocks appears as terraces, especially
on sunlit slopes, and
drumlins
deposited by Devensian ice are also visible in the upper
parts of Wharfedale.
Plate 1
An oblique aerial view of Upper Wharfedale in
January, looking north-north-west. Grass Woods is in the
foreground, and Conistone Dib centre right with Kilnsey
Crag centre left. The mouths of Littondale and
Langstrothdale are clearly visible in the clear winter light.
Photo: National Monuments Record.
