Lyell Collection
Quarterly Journal of Engineering Geology and Hydrogeology
Lyell Centre  |   Lyell Collection  |   Subscriptions   |   Geological Society  |   Email alerts  |   Online bookshop  |   Help

Keywords:
Author:
Advanced search>>
This Article
Right arrow Figures Only
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in ISI Web of Science
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow Request Permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Shepley, M.G.
Right arrow Articles by Streetly, M.
Right arrow Search for Related Content
GeoRef
Right arrow GeoRef Citation
Quarterly Journal of Engineering Geology and Hydrogeology; 2007; v. 40; issue.3; p. 213-227;
DOI: 10.1144/1470-9236/06-038
© 2007 Geological Society of London

The estimation of ‘natural’ summer outflows from the Permo-Triassic Sandstone aquifer, UK

M.G. Shepley1 & M. Streetly2

1 1The Environment Agency, Olton Court, 10 Warwick Road, Olton, Solihull B92 7HX, UK(e-mail: martin.shepley@environment-agency.gov.uk)
2 2Environmental Simulations International, New Zealand House, 160–162 Abbey Foregate,Shrewsbury SY2 6FD, UK

This paper examines some techniques that have been applied to estimate the ‘natural’ summer outflow for the Permo-Triassic aquifer of England, the second most important aquifer in the UK for public water supply. A method for naturalizing groundwater models is discussed and the naturalized flows predicted by the groundwater models of three Permo-Triassic Sandstone aquifers are compared against results of an analytical method to determine natural summer outflows for the equivalent aquifer properties. The results from the naturalization of the three groundwater models are broadly comparable and indicate that the simulated naturalized Q85 (i.e. the flow exceeded for 85% of the time) lies in the range of 70–90% of the naturalized long-term average recharge with a mean of 80% long-term average recharge. This provides the basis for a reasonably robust ‘first pass’ method to determine the natural summer outflows of an unconfined Permo-Triassic Sandstone aquifer unit. Some of this variability in the estimated natural summer outflows can be accounted for by the average distance from the ‘upstream’ edge of the aquifer unit to the discharge boundary (i.e. the perpendicular length). Comparison of the results of the naturalized simulations with the predictions of an analytical solution shows that the typical minimum summer baseflow of the analytical solution appears to be most consistent with the Q85 flow condition simulated by the groundwater models. However, it is clear that, at shorter perpendicular lengths (<1.5 km), the simple idealization of the aquifer implicit in the analytical solution is unable to predict natural summer outflows for the Permo-Triassic Sandstone aquifer system. This is likely to be a result of the increased significance of vertical components of flow in smaller aquifer units.

Key Words: groundwater management • groundwater modelling • naturalization




This article has been cited by other articles:


Home page
 Quarterly Journal of Engineering Geology and HydrogeologyHome page
M.G. Shepley, A.D. Pearson, G.D. Smith, and C.J. Banton
The impacts of coal mining subsidence on groundwater resources management of the East Midlands Permo-Triassic Sandstone aquifer, England
Quarterly Journal of Engineering Geology and Hydrogeology, 2008; 41: 425 - 438.
[Abstract] [Full Text] [PDF]