PARK DRAINAGE & GEOMORPHOLOGY
Eastfield Park, Northampton, is a large public open space in West Northamptonsire. It should not be confused with Eastfield Park in Wellingborough, a neighbouring town which lies 14.5km (9 miles) to the east. The Park is located about 4km (2.5 miles) north-east of the town centre. It covers an area of just over 24 hectares (around 60 acres) and is very roughly rectangular in shape, measuring approximately 825m long by 200-400m wide.
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The park is situated about 110m above sea level on a hill that rises from the floodplain of the River Nene to its crest in Moulton park. The figure below shows an exaggerated vertical profile along a line from the floodplain to the Moulton Park Industrial, passing through Weston Favell Village and Eastfield Park. (Heights in metres above sea level (m.a.s.l.) are based on Google Earth and may be subject to error.)
Although located on a south-facing slope, Eastfield Park is in the catchment of the Walbeck (or Wallbeck) Brook which drains south-westward into the Kingsthorpe Branch of the Nene in Kingthorpe Hollow, north of Northampton’s Town Centre.
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The figure below shows the location of Eastfield Park (in green) within the Walbeck Catchment. The base map is a 1 inch (1:63,360) Ordnance Durvey map dated, in part, 1857 (Sheet 52, Bedford). The direction of drainage from the park is shown as the dark blue dotted arrow. Walbrook Brook and its tributaries are labelled in lighter blue.
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Today, most of Walbeck Brook is underground in pipes and culverts but, historically, it drained a large area including much of what is now Bradlaugh Fields, the Racecourse, Parklands, Kingsley Park and Eastfield.
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The hill that Eastfield Park is located on, is capped with Blisworth Limestone, overlain in some areas with glacial till. Moving southwards, down the slope, deeper deposits are exposed: first those of the Rutland Formation, then the Northampton Sand Formation. Underlying the Blisworth Limestone is a layer mainly consisting of mudstone but with the Wellingborough Limestone Member (interbedded limestone and mudstone) running through it. Eastfield Park sits almost entirely on the Rutland Formation mudstones with the Wellingborough Limestone Member forming a horseshoe shaped band around the Lake (see figure below).
The Blisworth Limestone is a principal aquifer whereas the mudstones are almost impermeable, accounting for the numerous springs, flushes and seepages that occur close to the interface between these strata. There are numerous reports of springs and seepages in the area immediately to the north of Eastfield Park (in addition to mapped springs to the south and west). These sources of groundwater, coupled with the impermeable nature of much of the underlying rock, help to account for the fact that Eastfield Park is very poorly drained with some areas frequently waterlogged, particularly in winter and spring. This can, however, be considered beneficial (an Environmental Service) because the park holds back water that would otherwise drain rapidly downstreanm, possibly causing flooding.