HDR Engineering Inc. 10/6/2022 - Laserfiche WebLink

Exhibit A LL • RCRA 8 Metals (Ag, As, Ba, Cd, Cr, Hg, Pb & Se) via Environmental Protection Agency (EPA) test method EPA# 6010/7000, and • Toxicity Characteristic Leaching Procedure (TCLP) via EPA test method EPA 1211/6010D Due to the limited information regarding historical uses and potential contaminants of concern in the vicinity of the proposed stormwater treatment facility, chemical laboratory analysis of the environmental soil and/or groundwater samples submitted is based on general disposal facility requirements, which may vary based on the disposal facility. Samples will be submitted for standard laboratory turnaround time, which is approximately 7 to 10 business days. Follow-up analyses, based on initial analytical results (i.e., TCLP follow-up analysis) may result in a total standard turnaround time of up to 3 weeks. 13. Soil cuttings, purged groundwater (if encountered), and decontamination water from any suspect contaminated borings will be placed in steel 55-gallon drums. These Investigation Derived Waste (IDW) drums will be stored at the proposed stormwater treatment facility location, or at an adjacent location as provided by the City, pending chemical analysis. Once laboratory results for the environmental samples are obtained, coordinate the disposal of drummed IDW using a waste disposal subcontractor. Waste profile documentation required for disposal of the IDW will need to be signed by the property owner or a City representative. 14. Based on the geologic information in the vicinity of the improvements, determine the Site Class for seismic design and generate seismic design parameters. 15. Develop a geologic profile at the outfall structure area. This profile will be used to complete analysis and provide a visual representation of the anticipated subsurface soils. 16. Evaluate the susceptibility of the subsurface soils to liquefaction and assess the potential impacts to the proposed improvements. 17. Prepare draft and final geotechnical data reports presenting the results of field studies. This report will also provide a summary of the environmental conditions encountered at locations sampled, environmental laboratory test results, and recommendations for soil and groundwater handling and disposal during construction activities based on the information obtained during this investigation. The data report will include: • A description of the geotechnical site exploration program. • The logs of all borings and other site investigations, including any existing subsurface geotechnical data. • Groundwater measurements. • A description of the geologic and seismic settings for the corridor. • Results of all field tests conducted. • Installation details, logs, and measurements results of all geotechnical field instrumentation installed for the project or existing geotechnical instrumentation and measurement results usable for the project. • A description of all laboratory tests conducted and the test results, as well as any previous geotechnical laboratory test results that are relevant for the project. • A site plan showing boring locations and other pertinent features. 18. Archaeological monitoring will be performed for the geotechnical borings under the guidance of the Geotechnical Boring Inadvertent Discovery Plan (IDP), which will be developed in advance of the borings. See Task 701. Lexington Avenue Storm Drainage Improvements Preliminary Design Scope of Services 9