ARCHIVED REPORTS XR0000879 - Laserfiche WebLink

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`1 On August 23, 1999, the PHS/EHD approved a work plan submitted by Foothill Engineering to install replacement wells for MW#1, MW#2, and MW#3. These replacement wells were installed to correct the over screen conditions of the existing monitoring wells. Also, included in this work plan was the installation of three CPTs.To date CPT#1,CPT#2 and CPT43 have been installed. Soil and groundwater samples extracted during the installation of CPTs indicate gasoline contamination to a depth of eighty-five feet. On May 2 and 3, 2000 the soil borings for both MW#5 and MW#6 were made as described in the work plan of 3/17/2000. Monitoring wells were installed in both of these soil bores. The work plan of 3/17/2000 also included a soil bore and monitoring well (MW#4)to be installed in the sidewalk on the north side of Lafayette Street. This soil bore was not completed as planned. An unknown underground storage tank was encountered in the direct path of the soil bore. As a result of this encounter, the soil bore was abandoned and the local agencies were notified. A work plan to expand the horizontal definition of the contamination plume was approved in December of 2000.This work plan called for the installation of three new CPT's within the Caltrans R/W to the north of the project site. These CPT's were completed on March 8, 2001 and soil and water samples were extracted to a depth of 125 feet. Also, included in the work plan of December 2000 was the installation and testing of four new monitoring wells,MW-8S,MW-81),MW-7,MW- 9, to be placed on the project site or the adjacent property. These monitoring wells were completed on April 11, 2001. • In January of 2002 the owners of this property removed the apartment house structure on the east side of the property. At the time of this report that portion of the property is clear without any structures or other improvements. On August 9 & 10, 2002 the extraction well installed for the pump test was completed and developed. In December of 2002,work crews under the control of others,removed the buildings on the lot directly East of the site. This lot is not owned by the Olivarez's. Monitoring wells MW-8S and MW-8D were damaged and the caps and covers were removed along with the upper portion of the casing by the crews removing the buildings. These monitoring wells were repaired in March of 2003. Funds were made available for extraction well pump test. The pump test was performed on June 25, 2004. The pump test successfully demonstrated that the extraction well has influence with all areas that are contaminated. REPORT OF FINDINGS FOR THE FIRST QUARTER 2004 MONITORING EVENT Procedure On June 11,2004 Del Tech Geotechnical Support Services extracted water samples from all of the monitoring wells on the above stated property and extraction well EW-1.The work was supervised by Foothill Engineering. 2