Beginning on Tuesday January 31, 2006 and continuing until approximately February 17, 2006, drill rigs and support equipment will complete a monitoring well closure project. The main area of work is in the field north of Crow Drive to the west of Building 167 (Figure 3 of Report).
The purpose of this project is to decommission an historic research monitoring well field that is no longer in use. The well field was installed in the 1950's by the College of Engineering as part of a State Water Resources Control Board funded project to study deep-well injection and transport of materials such as sewage. Over twenty wells were installed to a depth of ninety feet. State and county regulations require that the wells are destroyed by filling them with grout (cement) to prevent accidental contamination of the groundwater aquifer. A full account of the well field history, investigation and decommissioning methods can be found in the attached December 8, 2005 Stellar Environmental Solutions' report Revised Technical Specifications for Well Destructions.
During the two to three weeks of activities, drill rigs will pump grout into the wells in two phases. The first phase will take one hour per well for grouting the lower segment. The second and final phase of closure will take approximately one- half day per well. Prior to the final grout injection during the second phase, well casings will be cut throughout the length of the wells. During these activities you may expect some truck engine noise. Additionally, in three locations (Figure 2 of Report), temporary groundwater monitoring equipment, known as piezometers, installed as part of the remediation and restoration project, will be removed by a drill rig.
In addition to the field north of Crow Drive, activity will take place near Buildings 164, 180 and 183. Following is the current schedule for work in these locations:
- Thursday February 2, 2006- two wells (225S and 224SE) between Buildings 164 and 180. Approximately two hours first phase well closure activity.
- Tuesday February 7, 2006- one well in the southwest corner of the Building 183 parking lot. Approximately two hours activity to remove with a drill rig.
- Thursday February 7, 2006- second phase to finish closure of two wells between Buildings 164 and 180. Approximately eight hours activity (four hours per well).
All wells have been sampled extensively by the campus Office of Environment, Health & Safety. There are no hazardous constituents present in the wells and there will be no soil disturbance that will create any dust emissions.
All work has been reviewed and approved by Contra Costa County Health Services and State of California Department of Toxics Substances Control.