Aquifer Measurements at Different Scales

Multilevel slug test data from five wells in a confined, sandy aquifer were analyzed to obtain an estimate of the vertical variation of the horizontal hydraulic conductivity, K(z). Hydraulic conductivity profiles for each well are shown with values of K(z) calculated between 563.0 and 13.5 ft/day. Vertically averaged values of hydraulic conductivity calculated from the multilevel measurements, K¯ = (l/b) ∫ o b K(z)dz, where b = the aquifer thickness, were between 204.5 and 35.9 ft/day. Conventional full aquifer pumping tests were conducted using the same wells for pumping and drawdown observations. Hydraulic conductivity values calculated from larger scale pumping tests, K o , were between 195.5 and 175.9 ft/day. To quantify the scale of measurement for the multilevel slug tests, the line source approximation (Ferris and Knowles, 1954) is analyzed to show that head and velocity fields induced by the slug test penetrate 10 to 100 feet into the aquifer.