Hydraulic properties of the Ironton and Galesville sandstones, Shakopee Mdewakanton Sioux Community, southeastern Minnesota, 2004

Abstract

Shakopee Mdewakanton Sioux Community, conducted an aquifer test December 6-22, 2004, to improve definition of the hydraulic properties of the Ironton and Galesville Sandstones beneath the Shakopee Community in southeastern Minnesota. Three wells were used in the aquifer test-a production well and two observation wells, located 3,247 feet northwest of the production well and 3,049 feet southeast of the production well. The production well, completed in the Ironton and Galesville Sandstones, was pumped at about 600 gallons per minute from 10:30 a.m. on December 6, 2004, to 3:26 p.m. on December 9, 2004. Drawdown and recovery water levels were measured in all three wells. Four curve-fitting methods and two graphical methods were used to estimate the transmissivity and storage coefficient of the Ironton and Galesville Sandstones. The four curvefitting methods were the Theis, Hantush, Hantush-Jacob, and Neumann-Witherspoon methods. These methods were applied to the drawdown and residual recovery curves of the observation wells. The two graphical methods were the Cooper-Jacob method and the Theis recovery method. The Cooper-Jacob method was applied to the drawdown curve of the production well and the drawdown curves of the two observation wells. The Theis recovery method was applied to the residual drawdown curves of the two observation wells. The transmissivity estimated using the six methods ranged from 450 to 650 feet squared per day. The average transmissivity for the six methods was 540 feet squared per day. The storage coefficient estimated using the six methods ranged from 4.2 to 5.7 x 10-5. The average storage coefficient for all six methods was 5.0 x 10-5. The hydraulic conductivity was estimated by dividing the estimated transmissivity by 45 feet. The average hydraulic conductivity for the six methods was 12.1 feet per day.