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<br />N <br />C"') <br />N Results of the slug-test analyses are preiented in table 2. Differences in results are due to the <br />N differing assumptions inherent in each Iechnique and the differing equations based on well design, Several <br />c:.. assumptions had to be made to use the three techniques: <br />;:;.. <br /> <br />I. The method of Hvorslev (1951) was assumed to be applicable for screened intervals that are <br />small in relation to aquifer thickness, This is a major assumption, as it decreases the effective <br />radius used in the solution, jeopardizing the assumption of horizontal steady-state flow, which <br />in turn may make estimated hydraulic conductivities too low. <br /> <br />2. The screened interval was used as the aquifer thickness in the method of Cooper and others <br />(1967). TIris may introduce errors because vertical flow almost certainly occurs to some degree <br />when a slug of water is introduced, probably resulting in higher esliri1~ted hydraulic <br />conductivities than actually exist. The radius of the screened interval was considered to be equ8J <br />to the radius of the well. This is acceptable if the sand pack is assumed to have a hydraulic <br />conductivity on the same order as that of the aquifer. <br /> <br />3. No changes in storage were assumed to occur due to water-table fluctuations in any of the <br />methods. <br /> <br />TABLE 2.--Estimated Iwrizontal and venical hydraulic conductivities at <br /> cluster-well sites, from slug-test data <br /> Estimated hydraulic conductivity (feet per day). and <br /> method of estimation used <br /> Depth Horizontal Vertical <br /> interval <br />Site and (feet below Bouwer Cooper and <br />cluster.well land and Rice Hvorslev others <br />designation surface) (1976) (1951) (1967) K,.=K2/Kh <br />WG035AN 4-6 (a) (a) (a) (a) <br />BN 8-10 6 12 47 3 <br />CN 13-15 13 24 88 6 <br />DN 16-18 2 4 8 1 <br />EN 28-30 I 2 6 .4 <br />WG044AN 6-8 5 10 20 4 <br />BN 10-12 5 9 26 3 <br />CN 20-22 I 2 8 .5 <br />DN 31-33 .4 .2 .6 .04 <br />WG053AN 6-8 ,3 (b) (c) (e) <br />BN 10-12 23 43 150 12 <br />CN 16-18 8 12 42 3 <br />DN 18-20 8 12 52 3 <br />EN 23-25 2 3 8 ,5 <br />WG062A 4-6 .9 2 (e) (e) <br />B 10-12 .3 ,8 2 .3 <br />C 15-17 .4 1 1 ,7 <br />D 20-22 4 6 22 2 <br />E 26.28 .01 .04 .15 .01 <br />a Water table below screened interval. <br />b Method not applicable for well screens extending above the water table. <br />C Method not applicable for shallow unconfined conditions. <br /> <br />-12- <br />