ARCHIVED REPORTS_1995 - Laserfiche WebLink

Home Browse Search

KLEINFELDER ATTACHMENT 1 ASSESSMENT OF SIDESLOPE INFILTRATION HARNEY LANE LANDFILL INTRODUCTION Harney Lane Landfill is operated by San Joaquin County and is locate approximately 15 miles northeast of Stockton, California. The landfill has been in operation sine the late 1940's and is currently entering closure. A question has arisen regarding the necessity of extending the proposed Chapter 15 cap (two feet foundation layer, one foot 1x10 cm/sec compacted clay, one foot vegetative layer) onto the steep 2:1 sideslopes of the landfill. OBJECTIVE The objective of this study is to compare the performance (capacity to reduce infiltration to the underlying waste) of the existing sideslope cover with that of a Chapter 15 cap. APPROACH The computer model HELP was used to evaluate sideslope infiltration under two scenarios (existing.sideslope and Chapter 15 cap). The.accuracy of the model is increased when site- specific information is used so sideslope soil samples were collected from four locations and analyzed for parameters used in the HELP model. RESULTS Soil Sampling Soil samples were collected at Harney Lane Landfill on March 4, 1994. A Backhoe was used to excavate the sideslopes at six locations. The sideslopes vary from-1.75:1 to 2:1. The height of the sideslopes is approximately 26 feet. The soil was found be homogeneous silty sand (SM) at all four sampling points. The maximum depth of excavation was five feet at all locations and waste was not encountered in any of these excavations. Samples collected from each location were tested at the Kleinfelder geotechnical laboratory in Stockton, California. Results of the testing are summarized below. See Appendix A for a detailed description of sampling and test results. File No.20-1008-49 April 6, 1994 Copyright 1994 Kleinfelder, Inc. Page 2 of 5 AIN