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August 1994 -5- 933-2713.003 <br /> 4.1.2 SlugTesting <br /> esting <br /> Sandy gravels generally yield poor core recovery; this was also the case for the Sunnyside <br /> project. In order to gather reliable information regarding permeability of the sandy gravel <br /> lenses, in-situ 'slug' testing was conducted. The slug testing involved introduction and <br /> subsequent removal of a 'slug' in each piezometer. The slug consisted of a 1.2-inch O.D., <br /> variable length sealed PVC pipe weighted with environmental-grade silica sand. The water level <br /> was measured immediately prior to slug-testing and the water level response during the test was <br /> measured using a Hermit Model-1000C transducer and data logger from In-Situ, Inc. The data <br /> logger provided data as early as 0.2 seconds after introduction or removal of the slug, which <br /> yielded valuable early time response data. <br /> Water level responses after slug introduction are referred to as "falling head tests", responses <br /> after slug removal are referred to as "rising head tests." At each piezometer, a falling head test <br /> was conducted first. After the water level returned to pre-test conditions, (or no further change <br /> in water level versus time was observed), a rising head test was conducted. By conducting both <br /> falling head and rising head tests in each piezometer, the results of the two tests can be <br /> compared to ensure their representativeness. <br /> 4.2 Slug Test Analysis <br /> 4.2.1 Methods <br /> The slug test data were analyzed using the Hvorslev and Bouwer and Rice Methods. The <br /> Hvorslev method (Hvorslev, 1951) and the Bouwer and Rice method (Bouwer and Rice, 1976) <br /> are empirical methods which involve a straight line fit to the slug test data on a log-linear graph. <br /> Both methods were used on the data. <br /> Golder Associates <br />