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Mr. Robert McClellon -3- HARNEY LANE SANITARY LANDFILL 4: Surface Crack Repair We will place bentonite in the deeper cracks, and track-walk the area of the side slope where the cracks have been observed. We have inspected the top deck of the landfill, and found a few areas where minor ponding may occur, and have marked these areas for correction. We did not observe cracks on the top deck. 5: Design Drawings for Owl Boxes and Hawk Perches: Please find attached, for your reference, the construction drawings for the Harney Lane Landfill Cover Reconditioning project, of which the installation of the owl boxes and hawk perches was a component. Detailed information regarding installation depth is found on Drawing No. 7—Raptor Habitat Details. These items were installed based on experience by Senior staff in the Flood Control Division of County Public Works, in which the damage to levees by burrowing rodents was better controlled by natural predators such as by owls and hawk perches, than control by bait and traps. We also believe this method to be more environmentally friendly. Therefore, we installed owl boxes and hawk perches to encourage the activity of those predators. A significant aspect of the perch design was the protection of the barrier layer. You will note that where the perches are installed, the clay barrier layer(as well as the foundation and vegetative layers) are replaced by concrete, which is much less permeable than the clay barrier soil it replaced. Two features were provided to ensure the long-term integrity of the cover at those locations. The first was the slight"funnel" shape of the concrete base. Being heavier than the surrounding soil, we anticipated that these bases could settle somewhat. By constructing the base wider at the top than at the bottom, such settlement would wedge the concrete more firmly into the excavation, thus ensuring a continuing seal between concrete and surrounding soil. The second feature was additional soil mounded over the base, to ensure that water could not pond at the base. This design was approved by RWQCB staff prior to issuance for bid. 6: Labeling and Repair of LFG Migration Monitoring Probes Solid Waste staff inspected the 12 migration monitoring wells, and found labeling cards missing in two wells. We labeled all wells on the exterior with the well number(1 through 12). In addition, the interiors of all well casings were further marked with color-coded indication of the individual probe depths. For example, the interior of monitoring well #2 was labeled "MP2-S" in red paint indicating that the shallow probe has the red probe top. The color of the red probe was also refreshed with red paint to clearly identify it. Similarly, "MP-2M" was written in blue paint, MP-21)" was written in yellow paint to indicate the medium and deep probes, and the color of those probes was also refreshed. All markings were done in permanent paint, rather than felt-tip marker. Where the labeling cards were found, they were retained. We have asked SCS Field Services to repair the probe tops at any probe that is loose or missing a valve.