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Emergency Remediation - 2480 Tracy Blvd., Tracy, CA. • Page 20 By raising its floor elevation, the necessity to operate a groundwater pump to prevent flooding of the basement of the new car-wash and lubrication-service facility has been eliminated for as long as fluctuations in the position of the water table do not cause it to rise to an elevation that is greater than approximately one foot above its elevation on May 2, 1996. It is expected that, given the as-built elevation of the basement slab, under normal conditions, this will not occur. However, on occasions when the regional water table rises due to unusually prolonged and intense seasonal rainfall or an infortuitous sequence of winter storms passes through the area, the natural water table may rise to above the elevation of the basement floor. Longer-term, cyclical changes in the regional may cause a more prolonged rise in the elevation of the water table. If the water table rises to an elevation close beneath the basement floor, or higher, it will 1 be necessary to pump from the dewatering sump to maintain the basement dry. The pumped water will be affected by low to moderate concentrations of components of gasoline. Plans should therefore be developed in a timely manner to design and install an ' alarm system and specify an operating procedure that will warn facility personnel of the imminence of basement flooding and provide for the treatment and disposal of the pumped water. Discharge of the pumped groundwater will be subject to authorization by the concerned regulatory agencies who should be consulting when a long-term plan for management of the basement dewatering system is developed. The results of analyses of samples of soil and groundwater, the engineering observations and evaluations, and all other information compiled during the site investigation and remediation work reported herein supports a conclusive finding that the soil and groundwater contamination affecting the subsurface beneath the subject property migrated down the groundwater gradient from a source located on the adjoining property at 574 West Grant Line Road that was formerly the site of a Chevron service station. A copy of this report should be sent to the SJCPHS under cover of a letter of transmittal that references Site No. 1408, which is that agency's designation for the property at 575 West Grant Line Road as the site of an unauthorized release of hydrocarbon fuels. A copy should also be made available, without restriction, to Chevron so that they may be ' informed of our findings and have access to the supporting data. A copy of this report should be permanently kept with other important documents related to the property. In the event of a sale of the property, the condition of the subsurface should be disclosed to any potential buyer. REFERENCES 1. The San Joaquin Company Inc. (1996): Plan for Emergency Remediation for Continuation of Construction 2480 Tracy Boulevard Tracy California. April 3, 1996. 2. The San Joaquin Company Inc. (1993):Master Health and Safety Plan.