Analysis of flow processes in fractured chalk under pumped and ambient conditions (UK)

Butler, A.P.; Mathias, S.A.; Gallagher, A.J.; Peach, D.W.; Williams, A.T.. 2009 Analysis of flow processes in fractured chalk under pumped and ambient conditions (UK). Hydrogeology Journal, 17 (8). 1849-1858. 10.1007/s10040-009-0477-4

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Official URL: http://www.springerlink.com/content/102028/

Abstract/Summary

An integrated set of different measurements has been used to study the behavior of groundwater in an observation well in a fractured rock formation, the UK Chalk, under pumped and ambient conditions. Under pumped conditions, the response of the open borehole was relatively straightforward with flow mainly concentrated along four discrete flow horizons. Furthermore, excellent correspondence was observed between the three methods of borehole flow velocity measurement: impeller flowmeter, heat-pulse flowmeter and dilution testing. Under ambient conditions, the system appeared more complicated. Specifically, in the upper half of the borehole, the impeller flowmeter exhibited substantial downward flow and the heat-pulse flowmeter exhibited almost negligible upward flow, whilst dilution testing indicated significant dilution. It was concluded that this was due to cross-flow occurring over the upper 29 m. Analysis of drawdown data, recovery data and a Drost analysis of the ambient cross-flow data yielded aquifer transmissivity estimates of 2,049, 2,928 and > 4,388 m2/day respectively. The discrepancy between the drawdown and recovery estimates was attributed to non-linear head-losses associated with turbulence and inertial effects. The difference between the pumping test and Drost results was explained by the flow during the pumping test bypassing this aforementioned 29 m region of rock.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	10.1007/s10040-009-0477-4
Programmes:	BGS Programmes 2009 > Groundwater science
ISSN:	14312174
Additional Keywords:	GroundwaterBGS, Groundwater, Aquifer characterisation, Catchment processes, Major aquifer, Chalk
NORA Subject Terms:	Earth Sciences Hydrology
Related URLs:	http://www.bgs.ac.uk/research/groundwate...
Date made live:	06 Jan 2010 10:25 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/8975

Item Type:

Publication - Article

Digital Object Identifier (DOI):

10.1007/s10040-009-0477-4

Programmes:

BGS Programmes 2009 > Groundwater science

ISSN:

14312174

Additional Keywords:

GroundwaterBGS, Groundwater, Aquifer characterisation, Catchment processes, Major aquifer, Chalk

NORA Subject Terms:

Earth Sciences
Hydrology