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. STRrE OF CALIFORNIA — ENVIRONMENTAL PROM ION AGENCY .CALIFORNIA REGIONAL WATER QUALITY CO CENTRAL VALLEY REGION 3443 ROUTIER ROAD, SUITE A SACRAMENTO, CA 95827-3098 PHONE: (916) 255-3000 FAX: (916) 255-3015 Ms. Carrie Cummings Forward Inc. P. O. Box 6336 Stockton, CA 95206 • NTF L BOARD— a�VIRGAJIMENTAL HEALTH PF �YII SRRVICE 93 JUL III pH 2: 22 FORWARD LANDFILL, SAN JOAQUIN COUNTY (Case No. 2209) 12 July 1993 We have reviewed the Eastern Ash Pit Extension Construction Quality Assurance (CQA) Report submitted by CH2M Hill on 22 June 1993. The report documented construction of the 80 -foot western expansion of the Ash Pit (waste management unit E) including the western side wall liner. The report provided CQA information and a construction certification as required by the facility's waste discharge requirements (WDRs). The report noted two significant problems encountered during construction of the unit. Several lab permeability measurements on the clay liner failed to meet the criteria specified in the CQA plan. Sample collection and testing procedures were suspected as a cause of the failing tests. However, we also suspect the low plasticity index for soils used in the areas of the failing tests may have contributed to the higher permeabilities. The CQA specifications and soil acceptance criteria should be reevaluated in light of the Ash Pit experience. The second problem involved geosynthetic materials used in construction. Phillips Fibers Corporation factory identification numbers were removed from the geosynthetic rolls by the local supplier before the rolls were delivered to Forward. The identification numbers were traced back to the supplier and the issue was satisfactorily resolved prior to installation. However, the local supplier's practice of removing the factory numbers prior to shipment to the construction site is not appropriate and should not be tolerated in future construction projects. The identification numbers link the manufacturer's certification to the rolls delivered to the site. If these numbers are removed prior to delivery, then the CQA protocol is violated and the material should be rejected. if low permeability geosynthetic liner material had been involved in this episode rather than filter fabric, we would not approve its use in the liner. You should review your contract specifications and implement any changes necessary to prevent this situation from happening again. Based on the CH2M Hill report and certification, plus our inspection of the unit on 17 May 1993, we approve the Ash Pit for waste discharge in accordance with the facility's WDRs. If you have any questions, please call Steve Rosenbaum at (916) 255-3131. v WILLIAM J. MARSHALL, Chief Chapter 15 Unit SER