House, A.R. et al

Groundwater levels data for the CEH River Lambourn Observatory at Boxford (01/02/2012 to 16/01/2015)

This dataset contains logged and manual observations of groundwater levels for piezometers at the Centre for Ecology & Hydrology (CEH) River Lambourn Observatory wetlands at Boxford, Berkshire, for the period February 1 2012 to January 16 2015 (01/02/2012 to 16/01/2015). The CEH River Lambourn Observatory located in Berkshire, UK (51.445o N 1.384o W) comprises c. 10 ha of riparian wetland which is bordered to the east by a 600 m stretch of the River Lambourn. The subsurface architecture comprises bedrock Chalk, overlain by gravels and then peat. Also presented are datums and ground levels for each piezometer, with data available for groundwater levels in peat, gravels and chalk. Groundwater heads were routinely checked at all piezometers by manually dipping observed water levels. At selected piezometers groundwater heads were monitored every 15 minutes using pressure transducers. Piezometers were not anchored to bedrock, though piezometer datum movement due to peat compressibility with saturation was discounted after comparisons of level surveys.

Publication date: 2016-10-19

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Supporting documentation

Format of the dataset : Comma-separated values (CSV)

Access and use conditions

This resource is made available under the terms of the Open Government Licence

You must cite: House, A.R.; Roberts, C.; Stratford, C.J.; Old, G.H.; Hewitt, E.J.; Bell, R.; Manamsa, K.; Woods, I.; Williams, P.; Townsend, J.; Sorensen, J.; Thompson, J. (2016). Groundwater levels data for the CEH River Lambourn Observatory at Boxford (01/02/2012 to 16/01/2015). NERC Environmental Information Data Centre. https://doi.org/10.5285/f4b8ca09-31a7-4f20-9fc1-eb35744e28d6

 

© Centre for Ecology & Hydrology (Natural Environment Research Council)

Where/When

Study area
Temporal extent
2012-02-01    to    2015-01-16

Provenance & quality

An existing gridded piezometer array originally installed by CEH in February 2012 was numbered 1-15. Supplemental piezometers to the same design specification were added in May 2013 to target observed temperature anomalies (locations 16-21). All locations comprise separate peat (P) and gravel (G) piezometers, with the exception of location 8 where the peat was too thin to complete an installation. Gravel piezometers were screened approximately 2.5-3.5 m below ground level (bgl) while peat piezometers were screened across the entire peat thickness. Peat piezometers in the pre-existing array were installed with the slotted screen extending above ground level, while bentonite was used to seal new piezometers with closed screens above ground level. Chalk (C) boreholes are also located at sites 3, 22 and 23; these were screened at 9.5-10.0, 8.0-9.0 and 5.0-6.0 m bgl, respectively.
At selected piezometers groundwater heads were monitored every 15 minutes using either In-Situ Level Troll 500sTM or SWS DiversTM installed to a consistent depth of 3 m bgl in gravel piezometers and to the base of the peat in peat piezometers. Groundwater heads were routinely checked at all piezometers by manually dipping observed water levels to quality control logged data susceptible to drift.
Piezometers were not anchored to bedrock, with the possible consequence that datums for water levels, taken at the top of piezometers, could move with the expansion and contraction of the peat due to saturation. Though it has been suggested that shallow (<0.5 m) peat generally possesses low compressibility, piezometer elevations were surveyed at periods of low (November 2013) and high (April 2014) water table level to ascertain any vertical movement. Surveys were carried out using Trimble 5600 DRTM total station and Trimble R8TM differential GPS (dGPS). Three total station setups were positioned with dGPS based on line of sight to fixed benchmark points, and to enable best coverage. Selected piezometers were included in the surveys based on line of sight to total station setups.
Results from the surveys showed differences could be grouped dependent on instrument setup. Mean differences for setups 1, 2, and 3 were 0.019, 0.000 and 0.006 m, respectively, which indicate systematic error and are likely due to inaccuracies in the Trimble R8TM GPS receiver due to obstructions, satellite geometry or atmospheric conditions. Variance around the means was not more than 0.003 m, within the accuracy for the Trimble 5600 DRTM total station. Hence, piezometer movement due to peat compressibility with saturation was discounted.

Correspondence/contact details

Dr. Gareth Old
Centre for Ecology & Hydrology
Maclean Building, Benson Lane, Crowmarsh Gifford
Wallingford
Oxfordshire
OX10 8BB
United Kingdom
eidc@ceh.ac.uk

Authors

House, A.R.
Centre for Ecology & Hydrology
Roberts, C.
Centre for Ecology & Hydrology
Stratford, C.J.
Centre for Ecology & Hydrology
Old, G.H.
Centre for Ecology & Hydrology
Hewitt, E.J.
Centre for Ecology & Hydrology
Bell, R.
British Geological Survey
Manamsa, K.
British Geological Survey
Woods, I.
British Geological Survey
Williams, P.
British Geological Survey
Townsend, J.
British Geological Survey
Sorensen, J.
British Geological Survey
Thompson, J.
University College London

Other contacts

Custodian
Environmental Information Data Centre
eidc@ceh.ac.uk
Publisher
NERC Environmental Information Data Centre
eidc@ceh.ac.uk

Spatial

Spatial representation type
Tabular (text)
Spatial reference system
OSGB 1936 / British National Grid

Tags

Topic categories
Environment , Inland Waters , Elevation , Geoscientific Information
INSPIRE Theme
Elevation
Hydrography
Environmental Monitoring Facilities
INSPIRE Theme
Soil
Keywords
Hydrology