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-� 1, 511111 WD <br /> f , <br />�y.. <br /> Work-Plan <br /> Stewart's Beacon <br /> Pro;eet No.b2-1y.1.2 <br /> �`. March 12,1990 <br /> Page: S <br /> 4. Periodically, samples will be collected from the influent and effluent r, <br /> waters, "is believed that tl-,e air stripping method will remove a majority <br /> of the hydrocarbons and the crrbon absorption units will remove the rest. <br /> Sampling intervals will depend on the pumping rate. The pumping rate <br /> will depend on two factor:: 1)aquifer recharge and/or, 2)desired ptuaping <br /> rate. If the aquifer can sustain a long term high rate of recharge(5 to 6 <br /> gptr%then the rate of pumping may need to be slowed down. <br /> S. To help evaluate the optimum pumping rate, the water level at the site <br /> will be monitored on a routine basis. The purpose of this is to monitor the <br /> zone of influence of the pumping well. The pump can be adjusted to sldm off <br /> of the surface of the water table or pump from deeper in the well. <br /> 6. The.volume of waterextracted during this process will depend:on three <br /> main factom <br /> rs. Fiest is the site of the plume and the level of contamination <br /> present:n it Secondly,will be the amount of monies available to perform <br /> -,. this task. Thirdly, is the limits the City of Tracy may put on us for <br /> discharge to their sewage treatment system. It is expected that between <br /> 10,000 and 100,000 gQ11ons will be treated. At a pumping rate of 3 gprn, <br /> r-�r <br /> about 30,000 gailor"s would be extracted in one week(7 days)..The exact <br /> pumping rate and volume would be determined as the project proceeds. <br /> M, <br /> 7. A schenitic of the extraction/treatment system is given in Figure 6. The <br /> fallowing section discusses the project future. <br /> 3.4.1 Catculatic)u of Radii of Influence of Extraction Welts <br /> - The method of calculating the radius of influence of a water well is well <br /> established. However,the involved variables must be known sufficiently well <br /> for precise determinations. Since there are no continuous aquitards above the <br /> water table,the aquifer at this site is,in practice,unconfined. The water table <br /> is sloping and therefore the recharge to the well,when pumped,is unequal from <br /> the different directions. The equation applying to a well in an unconfined <br /> aquifer with uniform flow(i.e. sloping surface) is (Todd, David K., 1980,p. <br /> 121f): . <br /> K= _ <br /> x r(hu+hd)(iu+id) (3.i} <br /> Where: <br /> K=hydraulic conductivity <br /> Q=well discharge <br /> ----------—r-�.distance.from well- --------—-- ---- -- --. - ---- �9 <br /> ----, -- - n a 3.1416' — -- <br /> �' hu=saturated thickness at distance r upgradient from well <br />