Wednesday, 23 April 2014

March 2014 overview

Groundwater levels, March 2014
March was unusually typical! After several months of exceptional rainfall, rainfall totals for March were within the normal range at the national scale. Rainfall was, however, below average over swathes of England and Wales, north-eastern Scotland and parts of Northern Ireland.

The groundwater recharge season has ended in many lowland areas, with hydrographs showing falling levels.  However, levels in the index wells remain within or above the normal range for the time of year.

Areas impacted by groundwater flooding are diminishing, however, it remains an issue in some areas, such as parts of Berkshire, south London, north Hampshire and Oxfordshire.

Hydrograph at Newbridge
(Permo-Triassic sandstone, south west Scotland)
Record monthly maximum levels were recorded in Skirwith and Newbridge boreholes (Permo-Triassic sandstones of north west England and south west Scotland) for the third successive month, though levels did peak during March.

For more information, see the Hydrological Summary for March 2014 [PDF].




Wednesday, 9 April 2014

BGS research recognised in the recent IPCC Fifth Assessment

Work initiated and funded by BGS through the Groundwater Science Directorate has been recognised by the Intergovernmental Panel on Climate Change (IPCC).  Research published by  Chris Jackson, Alan MacDonald, David Macdonald, George Darling, Brighid Ó Dochartaigh and Lou Maurice has just been cited in the Freshwater Resources chapter (Ch 3) of the Working Group II contribution to the Fifth Assessment Report (WGII AR5).


The Groundwater Science directorate continue to work on issues related to environmental change and groundwater resources and quality. For example, with work focussing on analysis of reconstructed groundwater levels, analysis of historic droughts (a NERC funded UK Droughts Programme project with a range of academic partners), and, along with CEH, analysis of the role of climate change as one of multiple stressors on water resources and ecosystem services across Europe with a case study focussing on the Thames Basin (the EU FP7 funded MARS project).


Montage of BGS Groundwater scientists cited in IPCC report

The papers cited are:
·         Jackson, C.R., R. Meister, and C. Prudhomme, 2011: Modelling the effects of climate change and its uncertainty on UK Chalk groundwater resources from an ensemble of global climate model projections. Journal of Hydrology, 399(1-2), 12-28
·         Guardiola-Albert, C. and C.R. Jackson, 2011: Potential Impacts of climate change on groundwater supplies to the Doñana wetland, Spain. Wetlands, 31(5), 907-920.
·         MacDonald, A.M., R.C. Calow, D.M.J. MacDonald, W.G. Darling, and B.É.Ó. Dochartaigh, 2009: What impact will climate change have on rural groundwater supplies in Africa? Hydrological Sciences Journal, 54(4), 690-703
·         Taylor, R.G., B. Scanlon, P. Döll, M. Rodell, R. van Beek, Y. Wada, L. Longuevergne, M. Leblanc, J.S. Famiglietti, M. Edmunds, L. Konikow, T.R. Green, J. Chen, M. Taniguchi, M.F.P. Bierkens, A. MacDonald, Y. Fan, R.M. Maxwell, Y. Yechieli, J.J. Gurdak, D.M. Allen, M. Shamsudduha, K. Hiscock, P.J.-F. Yeh, I. Holman, and H. Treidel, 2013a: Ground water and climate change. Nature Climate Change, 3(4), 322-329
·         Taylor, R.G., M.C. Todd, L. Kongola, L. Maurice, E. Nahozya, H. Sanga, and A.M. MacDonald, 2013b: Evidence of the dependence of groundwater resources on extreme rainfall in East Africa. Nature Climate Change, 3(4), 374-378.


Congratulations to everyone in BGS who has contributed to the IPCC reports.

Tuesday, 25 March 2014

Groundwater outlook - from March 2014

BGS Groundwater Science has been working with partners to develop a forecast for river flows and groundwater levels over the coming months — Hydrological Outlook UK.  You can view and download the most recent Hydrological Outlook from the website.  They are published monthly.  Here, we will summarise the latest groundwater outlook.
Hydrological Outlook from March 2014
(from http://www.hydoutuk.net/latest-outlook/)

As described in the previous post, groundwater levels in February remained high across most of the major aquifers.  Even with modest rainfall over the period to mid-April, groundwater levels are expected to remain high.

3 month outlook

Over a 3 month period (March to May), it is likely that levels will return to more normal conditions for the time of year in many areas.  Below average groundwater levels will probably persist in the Chalk of eastern England.  Levels are expected to remain high for the time of year in:

  • the southern Chalk (with an ongoing elevated risk of flooding in susceptible areas), and in
  • the Permo-Triassic aquifers of northwest England and southwest Scotland.
View or download the most recent Hydrological Outlook from the Hydrological Outlook UK website.


February 2014 overview

Groundwater levels, February 2014
Groundwater levels - February 2014

February was another exceptionally wet month, during which groundwater levels continued to rise across most aquifers.  Groundwater flooding occurred in the south and south-west of England.

Southern Chalk

Exceptional February groundwater levels were recorded over most of the southern Chalk.  Groundwater flooding was widespread from Dorset to Kent, and impacts on property and infrastructure were widely reported.  In some localities this flooding was the most severe since the winter of 2000/01.

Record monthly maximum levels were recorded at a number of monitoring sites, including:

Levels stabilised and fell overall across the south-western Chalk and South Downs by the end of the month.  However, groundwater flooding is ongoing in some areas, where it is likely to persist throughout the spring.

Northern and Eastern Chalk

Levels in the northern and eastern Chalk (East Anglia, Lincolnshire and Yorkshire) rose during February but remained at or below average, with the exception of Wetwang.

Permo-Triassic Sandstones

Groundwater levels were above normal in the Midlands and north Wales, and exceptionally high elsewhere.  Record monthly maxima were recorded for the second consecutive month at:
For more information, see the hydrological summary for Febuary 2014 [PDF].

Friday, 14 February 2014

January 2014 overview

Map showing index well groundwater levels for January 2014
Groundwater levels - January 2014
January saw a continuation of the exceptionally wet weather that began in December 2013.  For example, much of central and southern England received over twice the average rainfall for January.

The persistent rainfall has led to significant recharge across the southern Chalk outcrop, with new January maxima established for six Chalk boreholes.  For example, Chilgrove House well has overflowed.  We believe this well has the longest continuous observation of water levels in the UK - the record starts in 1836 - and such artesian conditions have only happened 6 times before.  Groundwater emergence in bournes has also been observed, e.g. the South Winterbourne (Dorset), Aldbourne (Berkshire), Lavant (Hampshire) and Nailbourne (Kent).

Levels are now increasing in the northern and eastern Chalk, which received less rainfall in December, but these are still below average.

Above average levels have been observed in the Permo-Triassic sandstones of the Midlands and north Wales.  In the north-west and south-west these have been exceptionally high, with record monthly levels recorded at Newbridge, Skirwith and Bussels.

In other aquifers, levels were typically above average, with Ampney Crucis (Jurassic limestone) registering exceptional levels.

With rising water levels in the southern Chalk, concerns over sewer surcharging and groundwater flooding heightened through January; flood alerts were widespread across the southern Chalk (from Dorset to Kent, but predominantly in the west), and were also issued for the Lower Greensand in south-west Surrey. The high water levels on the interfluves will gradually feed into the lower parts of catchments over a period of weeks to months, and it is likely groundwater flooding will persist well into the spring. In some of the major river valleys (e.g. the Thames Valley), elevated groundwater levels in superficial sands and gravels are exacerbating current flooding and the risk of future flooding

For more information, see the hydrological summary for January 2014 [PDF].

Wednesday, 13 February 2013

BGS on Channel 4 flooding documentary

David Macdonald appeared in last night's Channel 4 documentary, "The Year that Britain Flooded".  As well as impressive footage of flood events, the programme explained some of the meteorological and hydrogeological processes which contributed to the flooding.

David used a water level dipper to measure the depth to water in one of our boreholes. The water level was close to the top of the borehole casing (metal tube), which sticks up above the ground level.

This borehole penetrates a confined aquifer: in this area, the Upper Greensand Formation is confined by overlying low permeability clayey chalk (chalk marl).  The water level is frequently above ground level, so the borehole was designed with the extra casing above ground level to allow us to measure the water level accurately over a greater range.  At times, including earlier this year, the water level rises even higher and water naturally flows out of the casing when the flange sealing the top is removed.
An image from inside the borehole casing showing David lowering the water level dipper down into the hole.

Wednesday, 23 January 2013

December 2012 overview

Groundwater levels - December 2012
We expect to see groundwater levels rising in December, as this is part of the usual recharge season when soils are wet and rainwater can infiltrate into aquifers.  However, the final month of 2012 was still exceptional - as the map shows, groundwater levels in over three quarters of our index wells exceeded their December average.

Record levels for December were seen in 7 index wells, e.g. Skirwith in the Sherwood Sandstone and Wetwang in the Chalk.  The second highest levels on record were seen at a number of sites including the long record boreholes Chilgrove House (since 1836) and Compton (1894) in the South Downs.  Further extensive groundwater flooding is probable given the high levels in the Chalk.

Groundwater flooding has been occurring in some Chalk areas, and groundwater discharge has been contributing to high flows in some streams and rivers for which the Environment Agency have issued flood alerts.

For more information, see the hydrological summary for December 2012 [PDF].