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that there is very poor interconnecting between the sparse <br /> sand lenses . <br /> (3) The location of the soil contamination plume, if such <br /> exists as '''anything other than a small , localized area of <br /> contaminatTion under the excavated tank area, would not <br /> necessarily be related to the direction� of the ground water <br /> gradient . <br /> (Plume dispersion in a clayey medium is usually <br /> contained locally owing to low permeability of clays in <br /> general . The direction of dispersion in clays in the <br /> vadose zone would be' related to layer permeability and <br /> not to direction of groundwater gradient. Groundwater <br /> gradient direction would not enter into dispersion <br /> direction unless there were ,a floating product on the <br /> groundwater, which does not appearlto be the case <br /> here) . <br /> SUMMARY AND OPINIONS <br /> I <br /> Inasmuch as groundwater does not appear� to be contaminated, <br /> the direction of groundwater gradientli^s not pertinent. <br /> Dispersion in the vadose zone is likely, limited to a few <br /> tens of feet laterally and is not related to hydraulic <br /> gradient. <br /> Water well's in the area are generally completed below 150 <br /> feet while the contamination is' localiz,ed in the vadose zone <br /> above 80 ' . <br /> Additional investigative expense does not appear to be <br /> warranted 'to WJH based on these:. observations . <br /> WJH does riot deny the possibility that (there is a <br /> contamination plume and that it has not been delineated, <br /> however, it is the opinion of WJH that additional <br /> investigations that wil-1 entail-,; conside.r_able expense to the <br /> landowner are not warranted under the current circumstances . <br /> Quarterly ';water sampling and gradient determination for one <br /> year would be far more appropriate . <br /> J <br /> If the EHD has concerns regarding contamination in future <br /> water wells, then a better solution would be to restrict the <br /> drilling (or to not approve locations) :,- of future wells in <br /> the area; perhaps within ,a radius of 160 ' of the pulled tank <br /> site (Fig. 1) . This would not be an imposition on, properties <br /> other than that of Marei Diesel . <br /> i <br /> 3 <br /> i <br />