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g Addendum to Interim Corrective Action Plan Frontier Transportation, Inc. t April 14, 2006 - I Page 7 > Drawdown will be maintained at static level for 4 hours or until dewatering from (` the pumping well reaches asymptotic minimal flow levels for a period of at least 60 minutes. The aquifer test will be performed to identify lateral hydraulic conductivity, transmissivity, storativity and aquifer dewatering capability allowing technical and cost effective groundwater treatment. Variance in transmissivity (T), hydraulic conductivity (K), Specific Yield (S), the lateral extension of the cone of depression in this unconfined aquifer will be determined by pumping in two events at the two dewatering wells, MW-9 and MW4, near the contaminated area. The lateral variation of T within the aquifer unit will be determined using an average K determined by averaging conductivity data identified in the two wells. . The groundwater table will be measured in each of two pumping wellsand each of observation wells prior to equipment installation using an electronic water table measurement tape calibrated to 0 .01 -foot accuracy. The thickness of the aquifer will be determined from boring logs identifying the shallow groundwater retarding layer J underlying the first aquifer. The groundwater hydraulic gradient will be measured in all site-monitoring wells immediately prior to aquifer testing. Dedicated groundwater level indicators will be placed immediately above termination depth in each pumping and observation well and dedicated for the life of the aquifer test. The groundwater level loggers will be calibrated to 1 -minute test interval at 0.01 ` accuracy prior to installation of a submersible pump. Depth to groundwater will be measured throughout the pumping operation, proposed for a four hour and eight-hour :Ff 1+ period shouldrufficient. The pumping will be performed using an approximate 0.3 hp submersible pump with the discharge hose secured to a 2 thousand gallon portable tank on site and emptied ' by vacuum truck during aquifer testing. Pumping flow rate will be controlled and measured using a separate knife gate valve in each pumping well. Flow rate will be identified using a variable area rotameter with flow rate measurement range from 0.5 to 25 gallons per minute. Aggregate total discharge will be measured with a flow totalizer. Groundwater temperature and ambient pressure will be monitored periodically during the aquifer test. 1 . Contaminant mass, by measuring the pumping rate q, and knowing the water table depth in two observation wells, we can establish a value of k for field conditions. The equation in these conditions is i , i f 7