SITE INFORMATION AND CORRESPONDENCE

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Re-Manufacturing Closure Plan -2- 19 September 1991 permeability analysis after the first two lifts (one foot) , and again after the final two lifts. What is the methodology for repairing holes made for testing purposes in final cap? (bentonite pellets?) We need an actual field measurement of permeability according to Section 2541(c) of Chapter 15, which states in part, "Permeabi 1 i ties shall be determined primarily by appropriate field test methods in accordance with accepted civil engineering practice. . . . Appropriate compaction tests may be used in conjunction with laboratory permeability tests to determine field permeabilities as long as a reasonable number of field permeability tests are also conducted." Acceptable field test methods include the use of an air permeameter or double ring infiltrometer. A test pad should be constructed to verify the adequacy of the materials, design, equipment and construction procedures, proposed for the soil cap. The test pad should accurately represent the performance of the proposed full-scale cap. The test pad compaction and testing must be well documented, and the materials (soils) , procedures, and equipment used in the test pad must be the same as those used during construction of the full scale cap. If field permeability tests take a long time, they should be conducted on a test pad. This is only useful if the test pad and full scale cap are constructed the same way, using the same materials, equipment, etc. . Re-Manufacturing must describe how the test pad will be constructed and what the dimensions will be. The plan states that there will be a natural or synthetic drainage layer above the final cap and below the vegetative layer. What specific type of drainage layer will be used? Comment No. 5 A site plan, cross-section and general finish grade maps were included in the report. We still need an east-west cross-section, like figure 2, showing the profile of the waste and cap. Is the cap keyed-in to the east and west, as it is along the slough? Does the capped waste change the configuration of the slough? We need a plan view showing the final configuration of the channel . Comment No. 6 Based on storm water elevations for the Slough, is five to six feet of rip-rap enough? A curb and gutter will be placed along the southern boundary of the cap to divert site runoff around the cap. It will be tied into the 18-inch storm drain which runs through the property. Where, exactly, is the discharge point of the 18-inch storm drain? Comment No. 7 The plan states that the surface of the cap will be inspected on a monthly basis and following heavy precipitation events for a period of one year. After one year it will be monitored on a periodic basis. In addition, post-closure maintenance should continue on a monthly basis until the vegetation is very well established (if that does not occur within the first year) . What type of vegetation will be used and what is the rooting depth?