Author(s): Suny Sunjoto
Linked Author(s): Suny SUNJOTO
Keywords: Full penetration well, partial penetration well, pumping, recharging, correction factor. V
Abstract: Partial penetration well is a well which its depth or tip of its casing does not reach an impermeable stratum beneath the aquifer. Basic pumping system equations of Dupuit-Thiem formulas is based on Darcy's Law for confined and unconfined aquifer as well as for full penetration well with fully perforated casing. In the practical implementation, this condition rarely occurs especially for thick aquifer; therefore, many researchers developed a correction for those formulas from full penetration to be partial penetration wells. Despite the correction, those formulas still have difficulty to compute the design of pumping system due to its need for hydraulic gradient data which can only be defined by two real time data of piezometric head before and after pumping related to horizontal distance of both points. This value is not a constant for different discharge of pumping. This study developed 16 equations for the confined and unconfined aquifer based on Forchheimer's formula. There are 6 configurations of confined aquifer which all of those equations are valid for computation of pumping as well as of recharging. For the unconfined aquifer, there are 10 configurations which contain 4 equations valid for computation of pumping as well as of recharging, 3 equations are valid only for computation of pumping of partly perforated casing and the 3 remaining equations are valid only for computation of recharging of fully perforated casing. All of those above equations are in steady state flow condition and it can be harmonized easily to be unsteady state flow condition by following Sunjoto's equation. With these proposed equations, the design of well systems can be computed easily, as to a relationship between coefficient of permeability, shape factor, discharge of pumping and drawdown or built-up
Year: 2017