Effect of Well Radius on Drawdown Solutions Obtained with Laplace Transform and Green’ s Function Chiu-Shia Fen & Hund-Der Yeh Received: 30 July 2010 /Accepted: 20 September 2011 / Published online: 7 October 2011 # Springer Science+Business Media B.V. 2011 Abstract We have developed a drawdown solution for a partially penetrating well under constant flux pumping in a confined aquifer with finite thickness. The predictions of our solution diverge from the predictions of Hantush’ s solution (1961), particularly for problems with low ratios of well screen length to aquifer thickness. Furthermore, the predicted drawdown from Hantush’ s solution (1961) differs from that of Yang et al.’ s solution Water Resour Res 42:W0552, (2006) only near the well and at small time values as indicated in Yang et al. Water Resour Res 42:W0552, (2006). Our solution is based on Green’ s function with a columnar source (sink) that represents pumping from a finite-radius well. Hantush’ s solution (1961) and Yang et al.’ s solution Water Resour Res 42:W0552, (2006), however, were derived from Laplace transform techniques for pumping in a well with an infinitesimal and a finite radius, respectively. Keywords Analytical solutions . Confined aquifer . Groundwater hydraulics . Partially penetrating well . Laplace transform . Green’ s function Notations B Thickness of the aquifer [L] D =K z /S s , hydraulic diffusivity [L 2 /T] J 0 , J 1 Bessel functions of order 0 and 1 K r , K z Hydraulic conductivities in the radial and vertical directions [L/T] Q Pumping rate [L 3 /T] S s Specific storage [1/L] V’(z D ,τ,α) ¼ DW z; t ; l ð Þ= b r 2 w V 0 t ; a ð Þ A function given by Eqs. B2 to B8 Water Resour Manage (2012) 26:377–390 DOI 10.1007/s11269-011-9922-y C.-S. Fen Department of Environmental Engineering and Science, Feng Chia University, Taichung, Taiwan, Republic of China H.-D. Yeh (*) Institute of Environmental Engineering, National Chiao Tung University, Hsinchu, Taiwan, Republic of China e-mail: hdyeh@mail.nctu.edu.tw