TY - JOUR

T1 - How appropriate is the Thiem equation for describing groundwater flow to actual wells?

AU - Tügel, Franziska

AU - Houben, Georg J.

AU - Graf, Thomas

N1 - Publisher Copyright: © 2016, Springer-Verlag Berlin Heidelberg.

PY - 2016/12/1

Y1 - 2016/12/1

N2 - The Thiem equation of radial groundwater flow to a well is more than 100 years old and is still commonly used. Here, deviations caused by some of its simplifications are quantified by comparing the analytical to a numerical model that allows the implementation of more complex geometries. The assumption of horizontal flow in the Thiem equation, which necessitates uniform inflow over the entire screen length of the fully penetrating well, was found to cause deviations from actual pumping wells where the pump is placed above the screen, resulting in non-uniform inflow and additional drawdown. The same applies to partially penetrating wells, where inflow peaks and additional drawdown occur, especially when the well is screened in the lower part of the aquifer. The use of the Thiem equation in the near-field of a well should thus be restricted to situations where the screen inflow is relatively uniformly distributed, e.g. when it covers large portions of the aquifer thickness. The presence of a gravel pack and a background gradient, on the other hand, are of limited importance.

AB - The Thiem equation of radial groundwater flow to a well is more than 100 years old and is still commonly used. Here, deviations caused by some of its simplifications are quantified by comparing the analytical to a numerical model that allows the implementation of more complex geometries. The assumption of horizontal flow in the Thiem equation, which necessitates uniform inflow over the entire screen length of the fully penetrating well, was found to cause deviations from actual pumping wells where the pump is placed above the screen, resulting in non-uniform inflow and additional drawdown. The same applies to partially penetrating wells, where inflow peaks and additional drawdown occur, especially when the well is screened in the lower part of the aquifer. The use of the Thiem equation in the near-field of a well should thus be restricted to situations where the screen inflow is relatively uniformly distributed, e.g. when it covers large portions of the aquifer thickness. The presence of a gravel pack and a background gradient, on the other hand, are of limited importance.

KW - Analytical solutions

KW - Drawdown

KW - Hydraulic properties

KW - Thiem

KW - Water well

UR - http://www.scopus.com/inward/record.url?scp=84981240730&partnerID=8YFLogxK

U2 - 10.1007/s10040-016-1457-0

DO - 10.1007/s10040-016-1457-0

M3 - Article

AN - SCOPUS:84981240730

VL - 24

SP - 2093

EP - 2101

JO - Hydrogeology journal

JF - Hydrogeology journal

SN - 1431-2174

IS - 8

ER -