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PANOCHE BURN SITE REMEDIATION top of the canyon. The CIWMB and CH2M HELL obtained samples of the burn ash, underlying soil, and native material (i.e., background samples). The CIWMB and CH2M HILL field-changed the outlet of the retention dam from a corrugated metal pipe to a spillway. This design change will reduce the required maintenance. Week 6 - 10/28/96 through 11/1/96 After a review of the basin and retention dam elevations, the spillway elevation was lowered by 10 feet. Rains cancelled work for 1'/i days. All runoff was contained on site and within the ash boundary. Sukut continued pushing ash down the slopes and moving the material up the canyon. After the rain late in the week, the bottom of the canyon was too wet for equipment. Work continued on side slopes. Dark stains were discovered on the north slope, 5 to 10 feet from the edge. The CIWMB engineer directed Sukut to remove the black material and place it in the fill area. Week 7 - 11/4/96 through 11/8/96 Approximately 90 percent of the ash had been consolidated in the upper canyon by this time. Sukut continued to clear the side slopes and canyon bottom. Scrapers began placing the clay foundation layer at the interface of the buried tires, ash fill, and northwest canyon. Sukut removed 5 feet of the black, stained soil. Samples (CSS-1 through CSS-4) of the black soil from the north slope were sent to the laboratory for analysis. On November 6, 1996, the CIWMB engineer discovered two new stains at the upstream side of the old check dam. While removing the native clay material to increase the size of the retention basin, stains appeared as if groundwater had been reached or a layer containing moisture was exposed. These stains differed from the previous stains on the side slopes. All of the ash material and residue had been removed from this area during the week of October 28, 1996. Upon close examination, the CEWMB engineer discovered the soil was lightly coated with a heavy oil residue, had a faint odor of mothballs, and did not contain any black material found in the previous stains along the north slope. Also on November 6, 1996, CH2M HELL collected samples (CSS-5 through CSS-10) in the old check dam area to confirm metal contamination had been successfully removed. California Department of Water Resources issued a temporary construction water permit to Sukut to remove water from Little Panoche Creek. The previous water source in the local canal was no longer available. Week 8- 11/11/96 through 11/15/96 The U.S. EPA conducted a confirmation soil sampling program with an X-Ray Fluorescence (XRF) probe. The CH2M HILL engineer collected six spilt samples from the same U.S. EPA location. The samples (PF-SO-4, PF-SO-9, PF-SO-11, PF-SO-16, PF-SO-18, and PF-SO-23) were sent to the lab for analysis. By November 13, 1996, all of the ash, except for some in a small ravine on the south side next to the old retention basin, was removed and placed in the designated fill area. CIWMB 13