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Judge Steve Herrera Judicial Complex Update for December 14, 2009

Santa Fe County has begun remediation of contaminated soils at the site of the new courthouse. The County is working with the New Mexico Environment Department (NMED) and its contractor, Daniels B. Stephens & Associates(DBS&A), in the installation of a subsurface barrier that will keep contamination from reentering the site once excavation for the building begins. Equipment and materials are being mobilized on the site and installation of the barrier will begin next week (December 14-18, 2009).

The County will coordinate with the NMED’s Petroleum Storage Tank Bureau (PSTB) to oversee completion of the subsurface barrier. The process will start with conducting preliminary testing of materials, site set up, identify new well locations, and finally implementation of the subsurface barrier wall. These efforts will progress over the next month and a half. The County will participate in coordination of the construction activity until it is completed.

NMED press info:
Environment Department Begins Construction of Barrier at Santa Fe County Courthouse Construction Site
Structure to Aid in Ongoing Excavation of Contaminated Soil and Recovery of Old Gasoline Plume

(Santa Fe, N.M.) The New Mexico Environment Department has begun the first step in the cleanup of petroleum contamination at the Santa Fe County Courthouse site with the construction of a subsurface barrier within the perimeter of the excavation.

The subsurface barrier curtain will prevent the movement of old gasoline in soil and minimize the drawdown of that liquid within the excavation and during the construction dewatering activities. The wall will also maximize the recovery of old gasoline outside of the excavation.

“The construction of this structure is an important step in the cleanup of the courthouse site,” said New Mexico Environment Department Secretary Ron Curry. “Cleanup plans are moving ahead on schedule.”

Daniel B. Stephens & Associates, Inc., the engineering firm completing the cleanup for the department, selected Remedial Construction Services, L.P. to install the barrier after a competitive bidding process. NMED will over see the construction of the structure, which is configured to be 860 linear feet in each direction of the excavation. The top of the wall will be approximately 28 feet below street level and the bottom will be approximately 50 feet below street level.

The work includes assembling silos, a batching plant, high pressure jet pumps and a drilling rig at the site. The project is expected to be completed by Feb 18.

NMED and Santa Fe County have worked cooperatively in determining the details of the barrier configuration during preliminary meetings on the project. The wall is expected to cost $1 million.

Additional work at the site after the construction of the barrier will include excavation and removal of contaminated soil and the installation of an engineered soil vapor extraction system on properties adjacent to the site. NMED and Santa Fe County will continue to inform the public as the work progresses.

The county will begin dewatering and removing petroleum contaminated soil from the construction site in March. According to Santa Fe County’s contractor for the site, INTERA, “the estimated amount of petroleum-hydrocarbon soil present at the site is approximately 14,000 cubic yards, in which 8,500 cubic yards is located within the construction area where it can be readily excavated should the remediation plan for the site include contaminated soil removal.” The excavation plan, along with the dewatering plan, will be submitted to the Petroleum Storage Tank Bureau for technical approval on Dec. 14, according to INTERA. NMED’s Air Quality Bureau and Ground Water Quality Bureau are currently reviewing notices or permit applications submitted on behalf of the county.

In addition to installation of the barrier, Daniel B. Stephens is expected to install and operate a temporary remediation system from March to May. The water table will be lowered at that point of the excavation, which will be an ideal time to remove old gasoline around the perimeter of the eastern portion of the site. Daniel B. Daniel B. Stephens is expected to install the final remediation system to address the entire plume at that time. The department’s plan is to aggressively remove petroleum contamination at the site with a soil vapor extraction technique that will include the injection of heated process air into the soil at selected points to maximize the removal of the contamination.

NMED also proposes to use horizontal and vertical soil vapor extraction wells across the site to access hard to reach contamination. The horizontal wells will be installed beneath the existing District Attorney’s office building. Daniel B. Stephens will submit a final remediation plan containing plans and specifications for the project by early January. The department will issue a public notice and commence a public comment period for the project at that time.

The department expects the petroleum contamination will be removed from the site within two years of the startup of the system. The engineering company, which will continue to monitor the site after the contamination is removed, will ensure state groundwater standards are met.