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Appendix E PERMEABILITY TEST PROCEDURES Three in situ permeability tests were conducted at the San Joaquin County Landfill Development Site. Two types of in situ tests were conducted. The first type involved slug testing of a saturated sandstone in Well G-1 . The second type involved falling-head tests in Permeameters P-2 and P-3 to determine the permeability in the unsatu- rated zone immediately below proposed excavation depths. The results of these tests, together with laboratory permeability results, are presented in Table E-1. Slug testing is used to determine values of hydraulic conductivity for a water-bearing zone. Hydraulic conductivity is a measure of the water-transmitting characteristics of a material . Values obtained from a slug test represent a "point measurement" and provide an evaluation of aquifer permeability in the vicinity of the borehole. Slug testing involves inserting into or removing from a well a "slug" or object of known volume to create an instantaneous change of water level . At this site a PVC slug, 11 feet in length and 2.25 inches in diameter, was used. The slug was quickly lowered into the well , and the changes in water level were measured using a pressure transducer while the level returned to static (falling-head test) . After the water level stabilized, the slug was removed, and levels were again monitored as they returned to the original static water level (rising- head test) . Both falling- and rising-head tests were conducted at Well G-1 . The well is completed in the uppermost water-bearing zone, which is considered to be unconfined. EMCON slug tests are analyzed using a computer program that employs the method developed by Bouwer and Rice (1976) . This method of analysis assumes that the aquifer is uncon- fined, homogenous, isotropic, and infinite in areal extent and that