Pumping testing using a siphon well

Abstract

This paper determines the aquifer transmissivity and storage coefficient from timedrawdown data of pumping tests using a siphon well including a main pumped well along with ten brach pumped wells (deaired wells). The pumping data was analyzed by the Cooper-Jacob graphical method. The computed transmissivity and storage coefficient are 435.8 m2/day and 6.54 × 10-4 with pumping rates of 432 m3/day. Distances from the pumped wells to the observation well ranges from 225 to 268 m. The pumping tests from this siphon well (No. 38), one of the siphon wells in the Nansalum Pump Field, Tainan, Taiwan, were started at 10:40 a.m. on 19 March, 1992 and continued for 1534 min and then were shut simultaneously for water recovery. Groundwater withdrawals were pumped from the uppermost confined aquifer in the pump field. The siphon well is used to continuously provide a sufficient yield for pumping tests and irrigation, and is used when the pumped level and aquifer coefficients for more distant observation wells are to be measured and computed. These may not be achieved in less transmissive aquifers when a single pumped well is used. The siphon well can become a single pumped well in case the ten brach pumped wells (or deaired wells) are not used.