OR/15/048 Geographical setting

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Bearcock, J M, Smedley, P L and Milne, C J. 2015. Baseline groundwater chemistry: the Corallian of the Vale of Pickering, Yorkshire. British Geological Survey Internal Report, OR/15/048.

Study location

The Vale of Pickering is a low-lying flat-floored valley within the catchment of the River Derwent in North Yorkshire (Figure 1). The valley extends with an east-west orientation from Scarborough and Bridlington in the east, to the Howardian and Hambleton Hills in the west. The Vale is constrained to the north by the North York Moors, and to the south by the East Yorkshire Wolds. At its eastern extremity the Vale of Pickering is cut off from the North sea by a thick moraine deposit (Wilson, 1948[1]). Jurassic Corallian strata, which form the aquifer in this region, outcrop at the periphery of the Vale of Pickering. The aquifer constitutes a major resource in the River Derwent catchment (Reeves et al., 1978[2]; Tattersall and Wilkinson, 1974[3]). The sample sites in this study extend over an area of approximately 1000 km2. Figure 1 shows the location of the Corallian in the Vale of Pickering.

Land use and physical features

Arable farming is the dominant land use and industry in the study area (Figure 2). Westwards from Pickering, approximately half of the crops are cereals, the remainder include carrots, potatoes, sugar beet and oil seed rape. In the area extending eastwards from Pickering, cereals are generally not grown. Towards the north of the region, grasses, shrubs and trees prevail. These represent the higher ground and steeper slopes of the North York Moors. The grassland tends to line river valleys, the trees occupy lower slopes, and bog and shrub occupy the highest ground in the region. Scarborough, Pickering and Malton are the main urban centres.

Figure 1 Location of Corallian Group strata in north-east Yorkshire.
Figure 2 Land use around the Vale of Pickering.

The Vale of Pickering is a broad, flat, alluvial plain with an elevation less than 60 m AOD. The vale is constrained to the north by the steep dip slopes of the Jurassic Corallian strata, which form the lower slopes of the North York Moors, and to the south by the chalk escarpment of the East Yorkshire Wolds (Wilson, 1948[1]). Besides the main outcrop that forms the northern boundary of the vale, the aquifer crops out in a narrow strip between Gilling and Malton, and it is concealed beneath the impermeable Kimmeridge Clay in the centre of the region (Tattersall and Wilkinson, 1974[3]). The valley floor is covered by a variable thickness of alluvium (Wilson, 1948[1]).

The Vale of Pickering is drained by the River Derwent and its many tributaries (Figure 3), which mainly originate in the North York Moors and flow southwards. The River Derwent itself rises in the North York Moors, approximately 17 km north-west of Scarborough. Once in the low-lying vale the Derwent is joined from the east by the canalised River Hertford, and from the west by the River Rye. The River Rye itself has numerous tributaries that originate in, and drain southwards from, the North York Moors. The Derwent flows out of the Vale of Pickering and into the Vale of York via the Kirkham Gorge, which was formed by outflow of a glacial lake, formed in the vale during the Ice Age. Summer flows of these rivers are maintained by a substantial baseflow contribution from the main Corallian and other minor aquifers. The large areas of the vale covered by impermeable strata give rise to rapid stream responses during rainfall events (Reeves et al., 1978[2]; Wilson, 1948[1]).

Figure 4 shows the major urban areas and other places named in this report for reference. Sites of groundwater samples used in this investigation are given in Figure 5. Samples collected in this study were supplemented by data from the Environment Agency database (discussed in Groundwater data sources).

Figure 3 Physical features around the Vale of Pickering.
a) Shaded geology demonstrating the nature of the valley: flat bottomed, constrained to the north by the Corallian strata forming the lower slopes of the North York Moors and to the south by the Chalk Group
b) Geology and drainage network.
Figure 4 Places named in this study.
Figure 5 Location and data source of samples in this study.

References

  1. 1.0 1.1 1.2 1.3 WILSON, V. 1948. East Yorkshire and Lincolnshire. British Regional Geology. (London: HMSO.)
  2. 2.0 2.1 REEVES, M J, PARRY, E L, and RICHARDSON, G. 1978. Preliminary investigation of the groundwater resources of the western part of the Vale of Pickering. Quarterly Journal of Engineering Geology, Vol. 11, 253–262.
  3. 3.0 3.1 TATTERSALL, K H, and WILKINSON, W B. 1974. Groundwater Investigation in the Vale of Pickering: Final report on preliminary investigation. Yorkshire River Authority and Water Resources Board.