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Staff Report 8292
City of Palo Alto (ID # 8292) City Council Staff Report Report Type: Consent Calendar Meeting Date: 8/14/2017 City of Palo Alto Page 1 Summary Title: Amendment Number Three to Contract Number S15156222 with Golder Associates Title: Approval of Amendment Number Three to Contract Number S15156222 with Golder Associates to Increase Compensation by $91,300, for a Total Not- To-Exceed Amount of $311,622.00, to Perform an Evaluation of Selenium Concentrations and Leachate Levels at the Palo Alto Landfill, and to Extend the Current Three-Year Term by Four Months From: City Manager Lead Department: Public Works Recommendation Staff recommends that Council approve Amendment Number Three to Contract number S15156222 with Golder Associates for groundwater monitoring services to add evaluation of selenium concentrations and leachate levels at the Palo Alto Landfill to the scope of services, to increase compensation by $91,300 for a total not-to-exceed contract amount of $311,622, and to extend the term of the contract through September 2018. Background The 126-acre Palo Alto Landfill was filled to capacity and ceased waste acceptance in July 2011. The City properly closed and capped the landfill and in March 2016 received official approval of the landfill closure from the State. In June 2016 the San Francisco Bay Regional Water Quality Control Board (RWCQB) issued a new permit with updated Waste Discharge Requirements (Order No. R2-2016-0029), requiring the City to continue performing semi-annual groundwater monitoring and additionally, evaluate the landfill’s leachate containment performance and provide a selenium impact assessment. City of Palo Alto Page 2 The existing contract with Golder Associates, entered into on March 3, 2015, has a 3-year term and a $220,322 “not-to-exceed” amount. The contract has been amended twice to increase annual funding for Years 2 and 3. Discussion RWCQB is requiring the City to perform both a Leachate Control Evaluation and a Selenium Evaluation which includes sampling the leachate, groundwater and surface water at the Palo Alto Landfill/Byxbee Park as part of the updated permit discharge requirements. Golder Associates has recently prepared a Workplan to Evaluate Leachate Control and a Workplan to Evaluate Potential Sources of Selenium in Leachate and Groundwater, which were approved by the RWQCB in a letter dated May 1, 2017. The scope added in this third contract amendment is to execute the workplans and complete the leachate and selenium assessment reports. This amendment being proposed for Council approval would add the new state- required selenium study to the scope of the contract. An additional $91,300 and four months are required to perform the additional assessments. With the addition of the assessment work at the Palo Alto Landfill, the contract not-to- exceed amount will increase to $311,622 and the term of the contract will expire in September 2018. Resource Impact The cost of the additional monitoring scope of work included in this amendment is available in the Fiscal Year 2018 Refuse Fund operating budget. Environmental Review This project is exempt from CEQA under California Code of Regulations Title 14 Section 15306 - Information Collection. Attachments: Attachment A - Amendment Number Three For Contract S15156222. Attachments: S15156222 Amendment 3 AMENDMENT NO. 3 TO CONTRACT NO. S15156222 BETWEEN THE CITY OF PALO ALTO AND GOLDER ASSOCIATES, INC. This Amendment No. 3 to Contract No. S15156222 (“Contract”) is entered into August 14, 2017 (Amendment Effective Date), by and between the CITY OF PALO ALTO, a California chartered municipal corporation (“CITY”), and GOLDER ASSOCIATES, INC., a Georgia corporation, located at 425 Lakeside Drive, Sunnyvale, CA 94085 ("CONSULTANT"). City and Consultant are collectively referred to herein as the “Parties.” R E C I T A L S A. The Contract, dated effective March 3, 2015, was entered into between the Parties for the provision of Landfill Environmental Monitoring Services. B. Section 25.4 of the Contract authorizes the Parties to modify the contract by written amendment. C. The Parties now desire to amend the Contract to extend the Term an additional 4 months from its current expiration date May 26, 2018 to September 30, 2018, and increase the compensation from Two Hundred Twenty Thousand Three Hundred Twenty Two Dollars ($220,322) to a not- to-exceed amount of Three Hundred Eleven Thousand Six Hundred Twenty Two Dollars ($311,622) for a continuation of services as specified in Exhibit “A” of the Contract, Exhibit “A- 1” of Amendment No. 1 and to include an evaluation of Selenium concentrations and leachate levels at the Palo Alto Landfill in accordance with the Regional Water Quality Control Board permit requirements as specified in Exhibit “A-2” to the Contract. NOW, THEREFORE, in consideration of the covenants, terms, conditions, and provisions of this Amendment, the Parties agree: SECTION 1. Section 2 “TERM is hereby amended to read as follows: “2. TERM. The term of this Agreement is from the date of its full execution through September 30, 2018 unless terminated earlier pursuant to Section 19 of this Agreement. SECTION 2. Section 4 “NOT TO EXCEED COMPENSATION” is hereby amended to read as follows: The compensation to be paid to CONSULTANT for performance of the Services described in Exhibit “A” and Exhibit “A-1”, including both payment for professional services and reimbursable expenses, shall not exceed Sixty-One Thousand Five Hundred Ten Dollars ($61,510.00) for the first contract year, Seventy Seven Thousand Two Hundred Seventy Three Dollars ($77,273.00) for the second contract year, and One Hundred Forty Four Thousand Five Hundred Ten Dollars ($144,510) for the third contract year. In the event Additional Services are authorized, the total compensation for Services, Additional Services and reimbursable expenses shall not exceed Sixty- Seven Thousand Six Hundred Sixty One Dollars ($67,661.00) for the first contract year, Eighty DocuSign Envelope ID: 96EBA47B-86C9-4772-B877-2859A56AE580 Five Thousand Dollars ($85,000.00) for the second contract year and One Hundred Fifty Eight Thousand Nine Hundred Sixty One Dollars ($158,961.00) for the third contract year. The applicable rates and schedule of payment are set out in Exhibit “C-1”, entitled “HOURLY RATE SCHEDULE,” which is attached to and made a part of this Agreement. Additional Services, if any, shall be authorized in accordance with and subject to the provisions of Exhibit “C”, “C-2” and “C-3”. CONSULTANT shall not receive any compensation for Additional Services performed without the prior written authorization of CITY. Additional Services shall mean any work that is determined by CITY to be necessary for the proper completion of the Project, but which is not included within the Scope of Services described in Exhibit “A”, “A-1”, “A-2”. SECTION 3. The following exhibit(s) to the Contract is/are hereby added to read as set forth in the attachment(s) to this Amendment, which are incorporated in full by this reference: a. Exhibit “A-2” entitled “Scope of Services” - Amendment No. 3 b. Exhibit “A-3” entitled “Workplan to Evaluate Leachate Control”- Amendment No.3 c. Exhibit“A-4” entitled “Workplan to Evaluate Potential Sources of Selenium and Leachate in Groundwater” d. Exhibit “B-2” entitled “Schedule of Performance” - Amendment No. 3 e. Exhibit “C-3” entitled “Compensation” - Amendment No. 3 SECTION 4. Except as herein modified, all other provisions of the Contract, including any exhibits and subsequent amendments thereto, shall remain in full force and effect. IN WITNESS WHEREOF, the parties have by their duly authorized representatives executed this Amendment on the date first above written. SIGNATURES ON NEXT PAGE DocuSign Envelope ID: 96EBA47B-86C9-4772-B877-2859A56AE580 CITY OF PALO ALTO ____________________________ City Manager or Designee APPROVED AS TO FORM: _____________________________ City Attorney or designee GOLDER ASSOCIATES, INC Officer 1 By: Name: Title: Officer 2 (Required for Corp. or LLC) By: Name: Title: DocuSign Envelope ID: 96EBA47B-86C9-4772-B877-2859A56AE580 William Fowler EXHIBIT A-2 SCOPE OF SERVICES AMENDMENT NO.3 SCOPE OF SERVICES CONSULTANT shall complete the work described in the Workplan to Evaluate Leachate Control (Exhibit A-3) and the Workplan to Evaluate Potential Sources of Selenium and Leachate in Groundwater (Exhibit A-4) which were prepared by CONSULTANT for the CITY as a response to Waste Discharge Requirements Order No. R2-2016-0029 (WDR) adopted by the San Francisco Regional Water Quality Control Board (RWQCB) in June 2016. TASK 1 - LEACHATE MOUND MIGRATION ASSESSMENT AND SELENIUM ASSESSMENT CONSULTANT shall conduct a Leachate Mound Migration Assessment and Selenium Assessment on behalf of CITY to satisfy provisions C3 and C4 of the WDR. For the Leachate Mound Migration Assessment, this will include: Evaluating the presence of leachate at the Palo Alto Landfill (PALF) and determine if leachate is migrating to adjacent shallow groundwater or surface water; Determining if liquid elevations measured in the leachate piezometers are an accurate reflection of the amount of leachate in refuse or if they are a function of the performance of the leachate extraction system; and Determining if an inward gradient is necessary to prevent outward migration of leachate. The Selenium Assessment will include: Identification key geochemical processes and sources that may be responsible for an apparent increase in selenium concentration in groundwater beneath the Landfill over the last 20 years; Collection of field data to model geochemical speciation, redox conditions, and likely mineral occurrence and stability and shall assess geochemical processes within the boundary of the PALF site and site surrounds. 1a Sample Collection and Analysis CONSULTANT shall collect and analyze leachate, groundwater and surface water samples for select organic, inorganic and isotopic parameters as specified in the workplans. 1b Leachate Pump Testing CONSULTANT shall conduct field studies to measure leachate and groundwater levels under baseline (pumping) conditions, after the leachate system is shut off by the City and allowed to equilibrate, and after system restart by the City, as described in the workplans. 1c Data Analysis and Report Preparation CONSULTANT shall analyze the data and prepare a report summarizing the procedures, methods, results and conclusions of the Leachate Mound Migration Assessment and Selenium Assessment. DocuSign Envelope ID: 96EBA47B-86C9-4772-B877-2859A56AE580 CONSULTANT shall provide a draft report to the CITY for review and meet with CITY staff to discuss the conclusions and results. CITY will respond with comments or clarifications within 10 working days of draft report submittal. CONSULTANT shall prepare the final report and mail a hard copy to the CITY and the SWRCB, and provide a PDF copy to CITY. 1d Optional Sub-task: Drilling to Collect Additional Water Samples Additional groundwater sampling may be necessary to identify preferential leachate migration pathways. Based on the chemical test results and visual indications of seeps, CONSULTANT may propose drilling soil borings or temporary wells to collect additional groundwater samples. CONSULTANT shall prepare a brief workplan describing additional sampling locations and drilling methods shall be proposed by the CONSULTANT in a workplan and approved by CITY. Once approved, CONSULTANT shall implement the workplan. The results shall be reported in the final report described in (Task 1c). DocuSign Envelope ID: 96EBA47B-86C9-4772-B877-2859A56AE580 Golder, Golder Associates and the GA globe design are trademarks of Golder Associates Corporation WORK PLAN TO EVALUATE LEACHATE CONTROL Palo Alto Landfill Palo Alto, California Prepared For: City of Palo Alto For Submittal to the Regional Water Quality Control Board San Francisco Bay Region Prepared By: Golder Associates Inc. 425 Lakeside Drive Sunnyvale, Ca 94085 Distribution: (1) Copy - Regional Water Quality Control Board (via GeoTracker) (2) Copies – City of Palo Alto (2 bound with CDs) (2) Copies – Golder Associates Inc. January 2017 Project No. 053-7481-16 LE A C H A T E W O R K P L A N EXHIBIT A-3 DocuSign Envelope ID: 96EBA47B-86C9-4772-B877-2859A56AE580 g:\projects\palo alto lf\053-7481 (pal)\wdr workplans\leachate mound_evaluation\leachate mound migration assessment workplan.docx WORK PLAN TO EVALUATE LEACHATE CONTROL Palo Alto Landfill Palo Alto, California Prepared For: City of Palo Alto For Submittal to the Regional Water Quality Control Board San Francisco Bay Region Prepared By: Golder Associates Inc. 425 Lakeside Drive Sunnyvale, CA 94085 Golder Associates Inc. Tom Vercoutere, PG 4462 Käte Motroni Senior Consultant Senior Project Geologist EXHIBIT A-3 DocuSign Envelope ID: 96EBA47B-86C9-4772-B877-2859A56AE580 January 2017 i 053-7481-16 g:\projects\palo alto lf\053-7481 (pal)\wdr workplans\leachate mound_evaluation\leachate mound migration assessment workplan.docx Table of Contents 1.0 INTRODUCTION .............................................................................................................................. 2 1.1 Objectives and Scope of Work ..................................................................................................... 2 2.0 SITE DESCRIPTION ........................................................................................................................ 3 2.1 Physical Setting ............................................................................................................................ 3 2.2 Geologic Setting ........................................................................................................................... 3 2.3 Groundwater Occurrence ............................................................................................................. 4 2.4 Leachate Collection System ......................................................................................................... 4 2.5 Leachate Mounding ...................................................................................................................... 5 3.0 OFFSITE LEACHATE MIGRATION EVALUATION ........................................................................ 5 3.1 Sampling Plan ............................................................................................................................. 6 3.2 Organic Analyses ......................................................................................................................... 7 3.3 Inorganic Analyses ....................................................................................................................... 7 3.4 Stable Isotopic Analyses .............................................................................................................. 7 3.4.1 Oxygen-18/Deuterium Ratios ................................................................................................. 8 3.4.2 Carbon-13 and Dissolved Carbon............................................................................................ 8 3.5 Graphical Analyses ..................................................................................................................... 8 3.5.1 Piper/Stiff Diagrams ................................................................................................................. 9 3.5.2 Bivariate Plots ......................................................................................................................... 9 3.5.3 Mixing Plots ............................................................................................................................. 9 3.6 Suggested Laboratory Facilities for Non-Standard Analyses ...................................................... 9 4.0 LEACHATE POTENTIOMETRIC SURFACE................................................................................... 9 5.0 PORE PRESSURED DISSIPATION MODELING ......................................................................... 10 Tables Table 1 Proposed Leachate Evaluation Sample Locations Figures Figure 1 Site Location Figure 2 Groundwater and Leachate Monitoring Networks with Proposed Water Quality Sampling Locations Figure 3 Leachate Elevation Contours, October 1999 Figure 4 Leachate Elevation Contours, May 2016 Appendices Appendix A Sample Containers, Volumes, Preservatives and Holding Times EXHIBIT A-3 DocuSign Envelope ID: 96EBA47B-86C9-4772-B877-2859A56AE580 January 2017 2 053-7481-16 g:\projects\palo alto lf\053-7481 (pal)\wdr workplans\leachate mound_evaluation\leachate mound migration assessment workplan.docx 1.0 INTRODUCTION This work plan to evaluate the leachate collection and recovery system (LCRS) performance with respect to the prevention of leachate migration at the Palo Alto Landfill (Landfill) has been prepared in response to Waste Discharge Requirements Order No. R2-2016-0029 (WDR), Adopted June 2016, Provision C.3. – Leachate Control Evaluation. Leachate Control Evaluation: The Discharger shall submit technical reports acceptable to the Executive Officer to evaluate the LCRS with respect to the prevention of leachate migration to adjacent shallow groundwater and surface waters. This evaluation shall include the sampling and analysis of adjacent surface waters and determine whether the maintenance of an inward leachate gradient is necessary to prevent outward migration of leachate. The Report shall include additional proposed investigation and/or proposed changes to the SMP as warranted by the evaluation. The Landfill is located at the northeast end of Embarcadero Road in the City of Palo Alto (Figure 1). The Landfill facility is sited on an area of approximately 125 acres on the western margin of San Francisco Bay in a tidal salt marsh environment. It is bounded by Mayfield Slough to the east, Matadero Creek to the south, Emily Renzel Wetlands to the west, and the Palo Alto Water Quality Control Plant and a marsh area to the north. The Landfill began receiving waste in the early 1930s and operated as a Class III non- hazardous waste landfill. The landfill reached refuse capacity in July 2011, received regulatory certification in March 2016, and is now in its postclosure phase. 1.1 Objectives and Scope of Work The work plan objectives are as follows. Determine if leachate is migrating to adjacent shallow groundwater or surface water. This will be done by collecting leachate, groundwater, and surface water samples and analyzing the samples for geochemical parameters that could identify leachate contamination and if there are preferential pathways for leachate migration. These parameters include major cations and anions, metals and stable isotopes. If there are any key parameters identified from the results of the geochemical study that are not in the current SMP, they will be proposed to be included in the parameter list. Determine if an inward gradient is necessary to prevent outward migration of leachate particularly in relationship to the existing leachate mound. The results of the migration evaluation will provide data indicating whether there is offsite migration regardless of an inward gradient. Determine if the liquid elevations measured in the leachate piezometer are an accurate reflection of the amount of leachate in refuse or are they a function of the performance of the leachate extraction system. EXHIBIT A-3 DocuSign Envelope ID: 96EBA47B-86C9-4772-B877-2859A56AE580 January 2017 3 053-7481-16 g:\projects\palo alto lf\053-7481 (pal)\wdr workplans\leachate mound_evaluation\leachate mound migration assessment workplan.docx 2.0 SITE DESCRIPTION 2.1 Physical Setting The Landfill was constructed in a tidal marsh and slough environment on the edge of San Francisco Bay. The original Mayfield Slough, which underlies the site (see Figure 2), was blocked at the landfill boundaries during landfill construction. It has been speculated that backfilled areas of the channels at the landfill margins may be preferential pathways for leachate migration. Mayfield Slough, which is the bay-side extension of Matadero Creek, forms the southern and eastern border of the site. In the early 1950's, the original Mayfield slough was filled at the southern and western limits of the Landfill. The slough was also filled at a point along the eastern margin of the Landfill near the southern limit of what is now Byxbee Park. The water flowing from Matadero Creek to the original Mayfield Slough was routed along the southern and eastern perimeter of the site to its present day location. At that time, the original slough was still open to the north into the yacht harbor area. Water was also present in the cut-off slough that meandered inside the southern limits of the Landfill. In the early 1960's, an earth levee was constructed at the north end and the along the east side of the landfill to prevent refuse from entering Mayfield Slough. Based on early descriptions, bulky wastes and construction debris were used to fill the northern slough and were likely also previously used in the southern area of the site. By 1975, the original Mayfield Slough inside the limits of the Landfill had been completely filled. 2.2 Geologic Setting The tidal salt marsh environment on which the Landfill is constructed is underlain by approximately 6 to 16 feet of Younger Bay Mud – a very soft, unconsolidated deposit of organic-rich silt and clay with occasional lenses of sandy clay. This material is underlain by Older Bay Mud – a very stiff to firm clay, containing varying amounts of silt and lenses of sandy clay, sand, and gravel.1 In the site vicinity, the Bay Mud deposits interfinger with and grade into fine-grained alluvial deposits that have been shed off the Santa Cruz Mountains. Previous investigations at the site by various consultants have further defined the hydrogeologic conditions under and around the Landfill. Two zones of sand, designated as the 20-foot sand and the 40-foot sand, have been identified within the low-permeability Bay Mud. These sand units have been interpreted by previous investigators as being laterally continuous under part or all of the Landfill. The 20-foot sand is 2 to 4 feet thick, generally occurs at an elevation of about -20 feet mean sea level (MSL), is considered fairly continuous under the southern portion of the site, and is discontinuous or absent in the northernmost part of the site (see Figure 2). The 20-foot sand is likely below the base of the historic Mayfield Slough channel 1 Goldman, Harold B., editor. “Geologic and Engineering Aspects of San Francisco Bay Fill, Special Report 97.” California Division of Mines and Geology. 1969. EXHIBIT A-3 DocuSign Envelope ID: 96EBA47B-86C9-4772-B877-2859A56AE580 January 2017 4 053-7481-16 g:\projects\palo alto lf\053-7481 (pal)\wdr workplans\leachate mound_evaluation\leachate mound migration assessment workplan.docx bottom (estimated to be approximately -5 feet MSL near the duck pond and old harbor) and was not in direct contact with pre-landfill ground surfaces. The 40-foot sand is 2 to 10 feet thick, occurs at an elevation of about -35 to -40 feet MSL, and is generally considered continuous beneath the site. The sands are fine to medium grained and poorly graded. Thin gravel layers have been encountered in some locations. 2.3 Groundwater Occurrence Surface water and shallow groundwater occur in the tidal marsh environment surrounding the Landfill. The Bay Mud deposits therefore, are fully saturated within a few feet of ground surface. The water-bearing characteristics of the Bay Mud deposits are poor (i.e., very low hydraulic conductivities), so they are not considered aquifers. Due to their higher transmissivity, the 20-foot and 40-foot sand units have been identified as the primary water-bearing zones beneath the site even though groundwater occurs at shallower depths within the low-permeability Bay Mud. The porosity of the sand units has been estimated to be 25 percent.2 Hydraulic conductivity for the sands ranges from 5.1 x 10-4 to 1.2 x 10-4 centimeter per second (cm/sec) for the 20-foot sand, and 3.0 x 10-3 to 1.3 x 10-4 cm/sec for the 40-foot sand.3 Site groundwater monitoring wells are constructed to monitor either the 20-foot sand unit or the 40-foot sand unit. 2.4 Leachate Collection System The Landfill pre-dates waste disposal practices and regulations requiring engineered liners and leachate collection and removal systems (LCRS). Therefore, neither was constructed at the base of the Landfill prior to refuse placement. However, Bay Mud underlying the Landfill consists largely of clayey soils with permeabilities less than 1 x10-6 cm/sec, which is thought to form a natural liner under the site. Leachate is pumped from the Landfill through 24 6-inch diameter extraction wells. This extraction network comprises the Landfill’s LCRS. Well spacing averages approximately 300 feet, with locations selected based on historic information and leachate conditions at the time of well installation. In addition to the extraction wells that are 17 leachate piezometers. Leachate elevations are measured approximately monthly in fourteen of these piezometers. Collected leachate is discharged under an industrial waste discharge permit to the adjacent Palo Alto Regional Water Quality Control Plant (POTW). The quantity of leachate pumped from the LCRS to the POTW is routinely measured and reported in the semi-annual monitoring reports. Extraction well and piezometer locations are shown in Figure 2. An evaluation of the LCRS in operation at the Landfill was completed by EGI in January of 19954. The purpose of the evaluation was to (1) document the performance and effectiveness of the LCRS, (2) identify 2 EMCON. Quarterly Self-Monitoring Report, Palo Alto Landfill, City of Palo Alto, California. April 1994. 3 EMCON, April 1994. 4 Einarson Geosciences, 1995. Evaluation of Leachate Extraction System Performance, Palo Alto Landfill. January 1995. EXHIBIT A-3 DocuSign Envelope ID: 96EBA47B-86C9-4772-B877-2859A56AE580 January 2017 5 053-7481-16 g:\projects\palo alto lf\053-7481 (pal)\wdr workplans\leachate mound_evaluation\leachate mound migration assessment workplan.docx factors that limit the performance of the LCRS, and (3) provide recommendations to improve the performance of the LCRS over time (as needed). 2.5 Leachate Mounding One of the findings of the 1995 LCRS study was that inflow of groundwater from the Bay Mud underlying the Landfill was and may still be a significant component of leachate production at the Landfill. The inflow of groundwater is related to consolidation and settlement of the Bay Mud caused by loading of the Bay Mud with the refuse mass. Loading created elevated pore pressures in the saturated Bay Mud underlying the Landfill. The elevated pore pressures result in an upward hydraulic potential from the Bay Mud into the refuse mass. The length of time needed for the elevated pore pressures to dissipate has not been estimated but it may be several decades or more after loading ceases. In 1995, the groundwater component of the leachate in the Landfill was estimated at 20 percent. Leachate elevations are higher than groundwater and surface water levels outside the landfill. Leachate levels are typically between 3.5 feet and 16.5 feet. The current leachate mound shows a good correlation with the overall height and thickness of refuse, and therefore loading. The highest leachate levels occur in the south-central portion of the landfill, which are also the highest areas of the landfill. The high leachate levels have implications with regard to the potential for leachate to migrate outward and discharge to adjacent as seeps to surface water bodies or to discharge to groundwater. Since 1988, when leachate extraction began, the potentiometric surface of the leachate has had little variation, and the mound appears to be at equilibrium. Figures 3 and 4 show the leachate potentiometric surfaces in October 1999 and May 2016, respectively. As long as the hydraulic head within the Bay Mud is greater than the leachate head, the upward hydraulic potential should continue and prevent discharge to groundwater. Ongoing water- quality monitoring shows no direct indications of groundwater contamination from leachate. 3.0 OFFSITE LEACHATE MIGRATION EVALUATION Based on regular routine inspections, there is no visual evidence that leachate is leaving the landfill (i.e., seeps). The landfill and its final cover was designed and constructed to prevent infiltration of meteoric water. If there is, or has been, offsite migration of leachate from the base of the landfill, which is below sea level, it can be determined by comparing the geochemical and isotopic characteristics of leachate contained in the Palo Alto Landfill with those of nearby groundwater and surface water. The extent and level of contamination of groundwater due to leachate depends upon a number of factors including the chemical composition of leachate, its contrast with the composition of groundwater, and distance from the pollution source. A 1995 geochemical and isotopic evaluation of leachate from the landfill concluded that saline groundwater is a significant component of the EXHIBIT A-3 DocuSign Envelope ID: 96EBA47B-86C9-4772-B877-2859A56AE580 January 2017 6 053-7481-16 g:\projects\palo alto lf\053-7481 (pal)\wdr workplans\leachate mound_evaluation\leachate mound migration assessment workplan.docx leachate5, and therefore identifying a leachate release using typical inorganic indicator parameters alone may be problematic. Samples will be collected from leachate, groundwater, and surface water and analyzed for relevant organic, inorganic, and isotopic parameters. Data analysis will be performed using collected data in a phased approach. A geochemical characterization of the different water types will be conducted using graphical techniques that maximize the contrast between each source. Summary statistics will also be performed to provide an overview of the data and characterize the distribution of the data. Stable isotope data can be used to help identify leachate as a source of contamination. Additional, more complicated analyses will be performed as needed (e.g., principal components analysis). Additionally, historical data collected to date, will be evaluated for laboratory procedures and potential bias based on the varying methodologies used to measure concentrations. Lab methods will be evaluated for application to the samples collected and recommendations for data use will be provided. 3.1 Sampling Plan All samples will be analyzed for the same select organic, inorganic, and isotopic parameters. Analytical methods for leachate, groundwater, and surface water will be the same. There are 24 leachate extraction wells, 17 leachate piezometers, and 13 groundwater monitoring wells (see Table 1 and Figure 2). Not all locations at the Landfill will be sampled. The determination of the locations will be based on several factors as described below. Leachate samples will be taken from the Phase I, Phase IIA, Phase IIB, and Phase IIC areas with good spatial coverage. The samples will be collected from leachate extraction wells, leachate piezometers, and from leachate outfall at LP-1. LP-1 is considered representative of the entire leachate system. Groundwater samples will be collected from all wells that are screened across the 20-foot sands. No wells screened across the 40-foot sand will be sampled. Surface water samples will be collected from locations in Mayfield Slough, Matadero Creek, Emily Renzel Marsh, and the marshland north of the Landfill during the lower period of an ebb tide when surface water is flowing away from the edges of the landfill. Of particular interest are preferential pathways - locations where the old channels from the original Mayfield Slough intersect the current landfill boundary. If the analytical results from surface water samples indicate preferential pathway transport, or there is visual indications of seepage from the old channel fill, shallow temporary groundwater wells that correspond with areas of the original slough channels will be installed and screened across the channel backfill material. Samples will be collected and analyzed for the parameters that indicate leachate migration. If temporary wells are 5 Einarson GeoScience, Inc, “Geochemical Evaluation of Leachate Sourced, Palo Alto Landfill”, December 1995. EXHIBIT A-3 DocuSign Envelope ID: 96EBA47B-86C9-4772-B877-2859A56AE580 January 2017 7 053-7481-16 g:\projects\palo alto lf\053-7481 (pal)\wdr workplans\leachate mound_evaluation\leachate mound migration assessment workplan.docx installed, continuous coring of the borehole will be attempted with a dual-tube, direct push (e.g., a Geoprobe rig). Soil samples will be collected and logged by field staff using the visual-manual methods described in ASTM D2488 and under the supervision of a California-registered professional geologist or civil engineer. Boring logs and well completion details will be completed by the field geologist under the supervision of a California-registered professional geologist or civil engineer. Analyses that will be utilized for this evaluation are described below. 3.2 Organic Analyses Organic analyses that will be utilized for this evaluation are described below. The continued overall absence of landfill-related volatile organic compounds (VOCs) in groundwater samples from the thirteen Point-of- Compliance groundwater monitoring wells at the Landfill is an indication that the leachate extraction system is functioning properly and is effective. Groundwater wells and leachate effluent are sampled semiannually. For this work plan, offsite surface water and groundwater also will be sampled for VOCs. These analyses will be performed by BC Laboratories (BC Labs) in Bakersfield, California. 3.3 Inorganic Analyses Inorganic analyses that will be utilized for this evaluation are shown below. There are several inorganic parameters that are typical indicators for identifying leachate migration because of their typical high concentrations. The parameters to be analyzed for the evaluation include: Appendix I metals (antimony, arsenic, barium, beryllium, chromium, cobalt, copper, lead, mercury, nickel, selenium, silver, thallium, vanadium, and zinc); fluoride and bromide. Major anions and cations (sodium, potassium, calcium, magnesium, manganese, iron, chloride, bicarbonate alkalinity, total alkalinity, and sulfate). General indicators (chemical oxygen demand, biochemical oxygen demand, total organic carbon, total dissolved solids, ammonia-nitrogen, and nitrate-nitrogen). Field parameters (pH, specific conductance, temperature, oxidation-reduction potential [ORP] and dissolved oxygen) Leachate and surface water samples for metals will be filtered. There is limited leachate and groundwater historical background data for some of these parameters. Many of the parameters have only be analyzed for during the 5-year constituent-of-concern events. These analyses will be performed by BC Laboratories (BC Labs) in Bakersfield, California. 3.4 Stable Isotopic Analyses Stable isotope analysis can often be used to accurately identify leachate as a source of contamination in a monitored environment. Stable isotopes of certain elements (e.g., hydrogen, oxygen, sulfur, nitrogen, and carbon) provide additional information about geochemical transformations and sources that concentration data often cannot. Each element commonly has more than one stable isotope (i.e., varying number of EXHIBIT A-3 DocuSign Envelope ID: 96EBA47B-86C9-4772-B877-2859A56AE580 January 2017 8 053-7481-16 g:\projects\palo alto lf\053-7481 (pal)\wdr workplans\leachate mound_evaluation\leachate mound migration assessment workplan.docx neutrons) that slightly change the atomic mass of the element, which in turn changes reaction rates of the different isotopes, without changing its fundamental chemical properties. Contrary to radiogenic isotopes, stable isotopes do not decay, and therefore retain their mass through time. This constancy in elemental stable isotope chemistry and slight differences in reaction rate is commonly used to source reactions pathways for several elements in natural and industrial settings. Leachate, groundwater, and surface water should each have their own distinct isotopic signature to differentiate them from one another and from meteoric water, which is one of the standards from which variations are assessed. Meteoric isotopic composition is typically available via university research projects, including research at Stanford, University of California-Berkeley, and University of California-Davis. Leachate also may vary depending on what area of the landfill the leachate is coming from, thus providing even further differentiation. Isotopic analyses that will be utilized for this evaluation are described below. Sufficient samples will be collected from each possible source water, including slough and unimpacted groundwater (if a nearby source is available), and analyzed for selected isotopes. These samples will be analyzed by the Environmental Isotope Laboratory (EIL) at the University of Arizona or the Stable Isotope Laboratory at the University of California-Davis. The background samples may provide comparative standards to assess relative mixing with leachate. 3.4.1 Oxygen-18/Deuterium Ratios The stable isotopes of hydrogen (deuterium [2H]) and oxygen (oxygen-18 [18O]) are useful for identifying and tracing groundwater in the hydrologic cycle. In particular, because of the contrast between meteoric water and seawater isotope signatures, deuterium and oxygen-18 have proven very useful in seawater intrusion studies. 3.4.2 Carbon-13 and Dissolved Carbon One of the stable isotopes of carbon (carbon-13 [13C]) in dissolved carbon can be useful for identifying isotopic signatures of leachate in groundwater and surface water. 13C is a good tracer for leachate because biogeochemical processes within the landfill can produce a unique leachate signature. The concentrations of some inorganic parameters are typically higher in leachate than groundwater. However, when a significant contrast of these parameters is not present the carbon isotope can show significant differences. This makes it useful tracer for leachate in groundwater and surface water. 3.5 Graphical Analyses To analyze the data, graphical techniques that maximize the contrast between each source will be used to (1) evaluate the chemical character of each source, (2) compare and contrast the characteristics of the different sources, (3) identify the geochemical relationships between the leachate source and the groundwater and surface water source, and (4) estimate mixing ratios of the various sources. Graphical analyses that may be utilized for this evaluation are described below. EXHIBIT A-3 DocuSign Envelope ID: 96EBA47B-86C9-4772-B877-2859A56AE580 January 2017 9 053-7481-16 g:\projects\palo alto lf\053-7481 (pal)\wdr workplans\leachate mound_evaluation\leachate mound migration assessment workplan.docx 3.5.1 Piper/Stiff Diagrams When evaluating combinations of fresh water and salt water sources, absolute concentrations of ions can vary widely, but ratios of constituents remain relatively constant. Therefore graphical tools, which use ratios instead of absolute concentrations, such as Piper diagrams and normalized, or sliding-scale Stiff diagrams are useful for providing a "fingerprint" of the ionic character of the water. Piper diagrams are also useful for interpreting relationships that exist between various samples including mixing trends and geochemical reactions (e.g., cation exchange, precipitation and dissolution reactions, and sulfate reduction). 3.5.2 Bivariate Plots Bivariate plotting of chemical data using x-y scatter plots allows correlations between the two plotted constituents to be identified. Although a relatively simple method, the patterns of the bivariate scatter plots can be powerful analytical tools allowing identification of groups of water types, mixing, and the geochemical evolution of waters. 3.5.3 Mixing Plots Mixing of waters can be evaluated if the end member compositions and concentrations of the contributing waters are known. Using the most conservative dissolved ions, typically chloride and/or bromide, the percentage of each contributing end member can be determined using straightforward equations or graphical charts. The calculations assume that mixing is the dominant process affecting the concentration of the ion and that no geochemical reactions (i.e., sulfate reduction, cation exchange, etc.) are taking place. 3.6 Suggested Laboratory Facilities for Non-Standard Analyses Stable isotope analyses are non-standard analyses at industrial labs, but are commonly used in academic research at universities. The Stable Isotope Laboratory at the University of California – Davis is world renowned for high quality analyses and are consistently used by academic and industrial projects, alike. Golder has submitted samples to their facility on several occasions. Golder also has used the Environmental Isotope Laboratory at the University of Arizona on several projects. Golder recommends that the stable isotope samples be submitted to one of these laboratory facilities. Appendix A provides sample collection requirements for general chemical and isotope samples. Specific requirements are provided on the laboratory websites, and will be used during sample collection. Information regarding sampling and submission recommendations and forms are also included. 4.0 LEACHATE POTENTIOMETRIC SURFACE The elevated leachate levels measured in the leachate piezometers, that reflect the historically stable leachate mound, may be the result of the equilibrium between leachate generation rates and leachate extraction rates. Leachate elevations in the leachate extraction wells are not typically measured due to wellhead fittings or on-going extraction and fluctuating levels. EXHIBIT A-3 DocuSign Envelope ID: 96EBA47B-86C9-4772-B877-2859A56AE580 January 2017 10 053-7481-16 g:\projects\palo alto lf\053-7481 (pal)\wdr workplans\leachate mound_evaluation\leachate mound migration assessment workplan.docx High leachate heads (and correspondingly higher driving forces for leachate migration) can develop at the base of landfills, even without increase in the volume of leachate within the refuse – hydraulic head can increase temporarily and/or permanently due to the loading effects as the landfill is constructed. Now that the Landfill is in the postclosure period, future changes in load will not occur. In order to get an accurate leachate potentiometric surface, levels in all piezometers and extraction wells should be used. To do this, the following will be done: Install pressure transducers in several leachate extraction wells, leachate piezometers, and groundwater wells to provide spatial distribution and where possible, within well sets for correlation of leachate and groundwater in the 20-foot and 40-ffot sands. The pressure data will be used to establish baseline conditions and assess temporal changes in liquid levels. Shut down the leachate system and allow leachate levels to stabilize. Measure leachate elevations in all piezometers and accessible extraction wells Measure groundwater elevation groundwater monitoring wells Restart system, allow time for stabilization, and repeat the elevation measurements. Any increase in of leachate elevation within the piezometers while the extraction system is turned off, compared with leachate elevations while extraction is going on, will be noted. This could provide an indication of how extraction affects the leachate head. Any increase in groundwater elevations while the system is off should also be noted for the same effect extraction might have. Additionally, long-term monitoring of the leachate and groundwater potentiometric surfaces, as recorded by the pressure transducers, can be performed to assess responses to seasonal rainfall and possible tidal influences. 5.0 PORE PRESSURED DISSIPATION MODELING The loading of Bay Mud during landfill construction and the subsequent rise in pore pressure was determined to be responsible for creating an upward hydraulic potential from saturated Bay Mud into the refuse. An empirical geotechnical evaluation will be performed to assess the duration that may be necessary for the pore pressure to dissipate. EXHIBIT A-3 DocuSign Envelope ID: 96EBA47B-86C9-4772-B877-2859A56AE580 Groundwater Monitoring Wells 20-Foot Sand:G-9/88, G-13/88, G-14/88, G-16/88, G-17/88, and G-19 40-Foot Sand:Not Sampled Leachate Piezometers GR-7, GR-16, and GR-22 Leachate Extraction Wells E-5, E-19, and E-33 Leachate Outfall LP-1 Surface Water Locations Mayfield Slough:2 in the former Yacht Harbor 1 at the northeastern corner of the Landfill 1 along the eastern side of the Landfill 1 along the southeastern edge of the Landfill l 1 in the Mayfield Slough Remnant Matadero Creek:1 along Matadero Creek at the southern end of the Landfill Emily Renzel Marsh Area:1 west of monitoring well G-17/88 1 west of LP-1 1 west of monitoring well G-20 Table 1 Proposed Leachate Evaluation Sample Locations Palo Alto Landfill EXHIBIT A-3 DocuSign Envelope ID: 96EBA47B-86C9-4772-B877-2859A56AE580 0 1 i n 053-7481-16 FIGURE 2016-07-21 KMM KMM TLV TLV 1 PALO ALTO LANDFILLCITY OF PALO ALTO PALO ALTO LANDFILL SANTA CLARA COUNTY, CALIFORNIA SITE LOCATON TITLE PROJECT NO.REV. PROJECTCLIENT IF T H I S M E A S U R E M E N T D O E S N O T M A T C H W H A T I S S H O W N , T H E S H E E T S I Z E H A S B E E N M O D I F I E D F R O M : A N S I A CONSULTANT PREPARED DESIGNED REVIEWED APPROVED YYYY-MM-DD Pa t h : \ \ s u n n y v a l e \ d a t a \ P r o j e c t s \ P a l o A l t o L F \ 0 5 3 - 7 4 8 1 ( P A L ) \ F i g u r e s \ | F i l e N a m e : S i t e L o c a t i o n . d w g EXHIBIT A-3 DocuSign Envelope ID: 96EBA47B-86C9-4772-B877-2859A56AE580 PALO ALTO LANDFILL LEACHATE EVALUATION CITY OF PALO ALTO PALO ALTO LANDFILL SANTA CLARA COUNTY, CALIFORNA GROUNDWATER AND LEACHATE MONITORING NETWORKS WITH PROPOSED WATER QUALITY SAMPLING LOCATIONS 500250 FEET 0 SCALEEXPLANATION Groundwater monitoring well monitoring (20-foot sand) Groundwater monitoring well monitoring (40-foot sand) Leachate piezometer Leachate extraction well GR-21 and GR-22 are replacements for GR-4A and E-27P Topographic base map prepared for the City of Palo Alto by Mira Solutions, Inc., Union City, CA, using photogrammetric techniques. Aerial photography: April 4, 2016. IF T H I S M E A S U R E M E N T D O E S N O T M A T C H W H A T I S S H O W N , T H E S H E E T S I Z E H A S B E E N M O D I F I E D F R O M : A N S I A CONSULTANT DESIGN PREPARED REVIEW APPROVED YYYY-MM-DD TITLE PROJECT No.Rev. PROJECTCLIENT Path: \\sunnyvale\data\Projects\Palo Alto LF\053-7481 (PAL)\Figures\ | File Name: GW_MONITORING NETWORK_2016 topo_for workplan.dwg 0 1 i n 053-7481-16 FIGURE 2 2016-11-28 KMM KMM TLV TLV * Proposed groundwater and leachate sample location Proposed surface water sample location EXHIBIT A-3 DocuSign Envelope ID: 96EBA47B-86C9-4772-B877-2859A56AE580 PALO ALTO LANDFILLCITY OF PALO ALTO PALO ALTO LANDFILL SANTA CLARA COUNTY, CALIFORNA LEACHATE ELEVATION CONTOURS OCTOBER 1999 500250 FEET 0 SCALE Topographic base map prepared for the City of Palo Alto by Mira Solutions, Inc., Union City, CA, using photogrammetric techniques. Aerial photography: April 4, 2016. IF T H I S M E A S U R E M E N T D O E S N O T M A T C H W H A T I S S H O W N , T H E S H E E T S I Z E H A S B E E N M O D I F I E D F R O M : A N S I A CONSULTANT DESIGN PREPARED REVIEW APPROVED YYYY-MM-DD TITLE PROJECT No.Rev. PROJECTCLIENT Path: \\sunnyvale\data\Projects\Palo Alto LF\053-7481 (PAL)\Figures\ | File Name: GW_MONITORING NETWORK_2016 topo_for workplan.dwg 0 1 i n 053-7481-16 FIGURE3 2017-01-26 KMM KMM TLV TLV EXPLANATION Groundwater monitoring well monitoring (20-foot sand) Groundwater monitoring well monitoring (40-foot sand) Leachate piezometer in 1999 Leachate elevation (Ft.-MSL); Leachate elevation contour (Ft.-MSL) (Contours modified from Conor Pacific/EFW 1/19/2000) (-4.21) measured October 28, 1999 EXHIBIT A-3 DocuSign Envelope ID: 96EBA47B-86C9-4772-B877-2859A56AE580 PALO ALTO LANDFILLCITY OF PALO ALTO PALO ALTO LANDFILL SANTA CLARA COUNTY, CALIFORNA 500250 FEET 0 SCALE Topographic base map prepared for the City of Palo Alto by Mira Solutions, Inc., Union City, CA, using photogrammetric techniques. Aerial photography: April 4, 2016. IF T H I S M E A S U R E M E N T D O E S N O T M A T C H W H A T I S S H O W N , T H E S H E E T S I Z E H A S B E E N M O D I F I E D F R O M : A N S I A CONSULTANT DESIGN PREPARED REVIEW APPROVED YYYY-MM-DD TITLE PROJECT No.Rev. PROJECTCLIENT Path: \\sunnyvale\data\Projects\Palo Alto LF\053-7481 (PAL)\Figures\ | File Name: GW_MONITORING NETWORK_2016 topo_for workplan.dwg 0 1 i n 053-7481-16 FIGURE 4 2017-01-27 KMM KMM TLV TLV EXPLANATION Groundwater monitoring well monitoring (20-foot sand) Groundwater monitoring well monitoring (40-foot sand) Leachate piezometer in 2016 Leachate elevation (Ft.-MSL); Leachate elevation contour (Ft.-MSL) GR-21 and GR-22 are replacements for GR-4A and E-27P (7.35) measured September 30, 2016 * LEACHATE ELEVATION CONTOURS SEPTEMBER 2016 EXHIBIT A-3 DocuSign Envelope ID: 96EBA47B-86C9-4772-B877-2859A56AE580 Golder, Golder Associates and the GA globe design are trademarks of Golder Associates Corporation WORK PLAN TO EVALUATE POTENTIAL SOURCES OF SELENIUM IN LEACHATE AND GROUNDWATER Palo Alto Landfill Palo Alto, California Prepared For: City of Palo Alto For Submittal to the Regional Water Quality Control Board San Francisco Bay Region Prepared By: Golder Associates Inc. 425 Lakeside Drive Sunnyvale, Ca 94085 Distribution: (1) Copy - Regional Water Quality Control Board (via GeoTracker) (2) Copies – City of Palo Alto (2 bound with CDs) (2) Copies – Golder Associates Inc. January 2017 Project No. 053-7481-16 SE L E N I U M W O R K P L A N EXHIBIT A-4 DocuSign Envelope ID: 96EBA47B-86C9-4772-B877-2859A56AE580 g:\projects\palo alto lf\053-7481 (pal)\wdr workplans\selenium\selenium assessment work plan.docx WORK PLAN TO EVALUATE POTENTIAL SOURCES OF SELENIUM IN LEACHATE AND GROUNDWATER Palo Alto Landfill Palo Alto, California Prepared For: City of Palo Alto For Submittal to the Regional Water Quality Control Board San Francisco Bay Region Prepared By: Golder Associates Inc. 425 Lakeside Drive Sunnyvale, CA 94085 Golder Associates Inc. Tom Vercoutere, PG 4462 Käte Motroni Senior Consultant Senior Project Geologist EXHIBIT A-4 DocuSign Envelope ID: 96EBA47B-86C9-4772-B877-2859A56AE580 January 2017 i 053-7481-16 g:\projects\palo alto lf\053-7481 (pal)\wdr workplans\selenium\selenium assessment work plan.docx Table of Contents 1.0 INTRODUCTION .............................................................................................................................. 1 1.1 Objectives and Scope of Work ..................................................................................................... 1 2.0 SITE DESCRIPTION ........................................................................................................................ 3 2.1 Physical Setting ............................................................................................................................ 3 2.2 Geologic Setting ........................................................................................................................... 3 2.3 Groundwater Occurrence ............................................................................................................. 4 2.4 Historical Selenium Distribution. .................................................................................................. 4 3.0 WATER SAMPLES .......................................................................................................................... 5 4.0 ANALYTICAL PROGRAM................................................................................................................ 5 4.1 Stable Isotope Analyses ............................................................................................................... 5 4.2 Suggested Laboratory Facilities for Non-Standard Analyses ...................................................... 6 4.3 Post Sampling Data Analysis ....................................................................................................... 6 Tables Table 1 Selenium Concentrations in Groundwater and Leachate Table 2 Proposed Selenium Evaluation Sample Locations Figures Figure 1 Site Location Figure 2 Selenium Concentration Distribution in Groundwater Figure 3 Proposed Water Quality Sampling Locations Appendices Appendix A Sample Containers, Volumes, Preservatives, and Holding Times Appendix B Isotope Sample Procedures EXHIBIT A-4 DocuSign Envelope ID: 96EBA47B-86C9-4772-B877-2859A56AE580 January 2017 1 053-7481-16 g:\projects\palo alto lf\053-7481 (pal)\wdr workplans\selenium\selenium assessment work plan.docx 1.0 INTRODUCTION This work plan to evaluate the occurrence of elevated selenium in leachate and groundwater at the Palo Alto Landfill (Landfill) has been prepared in response to Waste Discharge Requirements Order No. R2- 2016-0029 (WDR), Provision C.4. - Selenium Evaluation. The WDR was adopted by the San Francisco Bay Regional Water Quality Control Board (RWQCB) in June 2016. Selenium Evaluation: The Discharger shall submit technical reports acceptable to the Executive Officer to evaluate the potential source(s) of elevated selenium in leachate and groundwater adjacent to the site. This evaluation shall include the sampling and analysis of adjacent surface waters. The Report shall include additional proposed investigation and/or proposed changes to the SMP as warranted by the evaluation. The Landfill is located at the northeast end of Embarcadero Road in the City of Palo Alto (Figure 1). The Landfill facility is sited on an area of approximately 137 acres on the western margin of San Francisco Bay in a tidal salt marsh environment. It is bounded by Mayfield Slough to the east, Matadero Creek to the south, Emily Renzel Marsh to the west, and the Palo Alto Water Quality Control Plant and a marsh area to the north. The Landfill began receiving waste in the early 1930s and operated as a Class III non-hazardous waste landfill. The landfill reached refuse capacity in July 2011, received regulatory certification in March 2016, and is now in its postclosure phase. 1.1 Objectives and Scope of Work The objectives of this work plan are to identify key geochemical processes and sources that may be responsible for an apparent increase in the selenium concentrations in groundwater beneath the Landfill over the last 20 years. The intent of the program is to investigate the nature of the selenium concentration increase and evaluate the landfill’s effect on elevated selenium in the vicinity of the property, and determine, if possible, the nature of the geochemical process that resulted in selenium concentration increases. Elevated selenium concentrations may be due to a mass transfer (i.e., point or non-point source such as a leachate release) or a phase change in the surrounding geologic material (i.e., the selenium solubility has changed). A water-quality analytical program has been designed to identify potential selenium sources at the Site. Data collected during the field program will be used to model geochemical speciation, redox conditions, and likely mineral occurrence and stability. In addition, an assessment of geochemical processes within the boundary of the site and area directly adjacent to the property will be performed. Selenium is a complex oxy-anion that has variable mobility at various redox states. It does not usually form mineral species, however, it is commonly associated with sulfur minerals due to similar chemical affinity and atomic radii. It is therefore important to understand the sources and occurrence of sulfur at the Site. The investigation will EXHIBIT A-4 DocuSign Envelope ID: 96EBA47B-86C9-4772-B877-2859A56AE580 January 2017 2 053-7481-16 g:\projects\palo alto lf\053-7481 (pal)\wdr workplans\selenium\selenium assessment work plan.docx focus on potential sources of selenium, including the landfill, pyritic bay muds, and other potential sources in the area (e.g., agricultural run-off, etc.). To meet these objectives the work plan includes the following tasks: Collect and analyze groundwater samples from existing monitoring wells where historically increasing selenium concentrations have been observed (G-3A, G-8-88, G-9-88, G-10-88, and G-20) and from all well pairs (G-1A/G-9-88, G-12-88/G-13-88, and G-14-88/G-15-88). See Figure 2. Collect and analyze leachate samples from approximately six existing leachate wells and piezometers to assess areal distribution of selenium in leachate. Collect and analyze groundwater samples from any accessible nearby monitoring wells to characterize potential ambient/background selenium distribution. Collect and analyze surface water samples from approximately six locations in Mayfield Slough, Matadero Creek, Emily Renzel Marsh, and the Marshland north of the Landfill to assess selenium distribution in surface water bodies adjacent to the Landfill. Proposed water quality sampling locations are shown on Figure 3. EXHIBIT A-4 DocuSign Envelope ID: 96EBA47B-86C9-4772-B877-2859A56AE580 January 2017 3 053-7481-16 g:\projects\palo alto lf\053-7481 (pal)\wdr workplans\selenium\selenium assessment work plan.docx 2.0 SITE DESCRIPTION 2.1 Physical Setting The Landfill was constructed in a tidal marsh and slough environment on the edge of San Francisco Bay. The original Mayfield Slough, which underlies the site (see Figure 3), was blocked at the landfill boundaries during landfill construction. It has been speculated that backfilled areas of the channels at the landfill margins may be preferential pathways for leachate migration. Mayfield Slough, which is the bay-side extension of Matadero Creek, forms the southern and eastern border of the site. In the early 1950's, the original Mayfield slough was filled at the southern and western limits of the Landfill. The slough was also filled at a point along the eastern margin of the Landfill near the southern limit of what is now Byxbee Park. The water flowing from Matadero Creek to the original Mayfield Slough was routed along the southern and eastern perimeter of the site to its present day location. At that time, the original slough was still open to the north into the yacht harbor area. Water was also present in the cut off slough that meandered inside the southern limits of the Landfill. In the early 1960's, an earth levee was constructed at the north end and the along the east side of the landfill to prevent refuse from entering Mayfield Slough. Based on early descriptions, bulky wastes and construction debris were used to fill the northern slough and were likely also previously used in the southern area of the site. By 1975, the original Mayfield Slough inside the limits of the Landfill had been completely filled. 2.2 Geologic Setting The tidal salt marsh environment on which the Landfill is constructed is underlain by approximately 6 to 16 feet of Younger Bay Mud – a very soft, unconsolidated deposit of organic-rich silt and clay with occasional lenses of sandy clay. This material is underlain by Older Bay Mud – a very stiff to firm clay, containing varying amounts of silt and lenses of sandy clay, sand, and gravel.1 In the site vicinity, the Bay Mud deposits interfinger with and grade into fine-grained alluvial deposits that have been shed off the Santa Cruz Mountains. Previous investigations at the site by various consultants have further defined the hydrogeologic conditions under and around the Landfill. Two zones of sand, designated as the 20-foot sand and the 40-foot sand, have been identified within the low-permeability Bay Mud. These sand units have been interpreted by previous investigators as being laterally continuous under part or all of the Landfill. The 20-foot sand is 2 to 4 feet thick, generally occurs at an elevation of about -20 feet mean sea level (MSL), is considered fairly continuous under the southern portion of the site, and is discontinuous or absent in the northernmost part of the site (see Figure 2). The 20-foot sand is likely below the base of the historic Mayfield Slough channel 1 Goldman, Harold B., editor. “Geologic and Engineering Aspects of San Francisco Bay Fill, Special Report 97.” California Division of Mines and Geology. 1969. EXHIBIT A-4 DocuSign Envelope ID: 96EBA47B-86C9-4772-B877-2859A56AE580 January 2017 4 053-7481-16 g:\projects\palo alto lf\053-7481 (pal)\wdr workplans\selenium\selenium assessment work plan.docx bottom (estimated to be approximately -5 feet MSL near the duck pond and old harbor) and was not in direct contact with pre-landfill ground surfaces. The 40-foot sand is 2 to 10 feet thick, occurs at an elevation of about -35 to -40 feet MSL, and is generally considered continuous beneath the site. The sands are fine to medium grained and poorly graded. Thin gravel layers have been encountered in some locations. 2.3 Groundwater Occurrence Surface water and shallow groundwater occur in the tidal marsh environment surrounding the Landfill. The Bay Mud deposits therefore, are fully saturated within a few feet of ground surface. The water-bearing characteristics of the Bay Mud deposits are poor (i.e., very low hydraulic conductivities), so they are not considered aquifers. Due to their higher transmissivity, the 20-foot and 40-foot sand units have been identified as the primary water-bearing zones beneath the site even though groundwater occurs at shallower depths within the low-permeability Bay Mud. The porosity of the sand units has been estimated to be 25 percent.2 Hydraulic conductivity for the sands ranges from 5.1 x 10-4 to 1.2 x 10-4 centimeter per second (cm/sec) for the 20-foot sand, and 3.0 x 10-3 to 1.3 x 10-4 cm/sec for the 40-foot sand.3 Site groundwater monitoring wells are constructed to monitor either the 20-foot sand unit or the 40-foot sand unit. 2.4 Historical Selenium Distribution. Groundwater beneath the site has been sampled and analyzed for dissolved selenium approximately once every 5 year schedule since the mid 1990s. The sampling began when selenium was listed as a constituent of concern (COC) in groundwater for compliance with the existing Waste Discharge Requirement at that time (WDR Order Number 99-026). Additional samples were collected as part of specific water quality characterization programs. Up until 2016, leachate has also been routinely analyzed for selenium for compliance with the industrial wastewater discharge permits issued by the Palo Alto Regional Water Quality Control Plant. Under the new Discharge Permit No. 16106, selenium is no longer a required parameter. Table 1 and Figure 2 present tabular and graphical summaries of the historical selenium concentrations for groundwater and leachate. Figure 2 shows the areal distribution of selenium in groundwater since 2000. The data presented in Table 1 and on Figure 2 show that the selenium concentrations in groundwater in both the 20-foot sand and the 40-foot sand increased through the 2014 COC event and have decreased since then, with only one exception. It is noteworthy that the increases and decreases in both water-bearing zones occurred simultaneously. The data also shows that selenium concentrations are typically higher in groundwater beneath the northern portion of the site relative to the southern portion of the site. 2 EMCON. Quarterly Self-Monitoring Report, Palo Alto Landfill, City of Palo Alto, California. April 1994. 3 EMCON, April 1994. EXHIBIT A-4 DocuSign Envelope ID: 96EBA47B-86C9-4772-B877-2859A56AE580 January 2017 5 053-7481-16 g:\projects\palo alto lf\053-7481 (pal)\wdr workplans\selenium\selenium assessment work plan.docx 3.0 WATER SAMPLES Every effort will be made to sample Site monitoring locations as well as monitoring locations and wells outside of the property boundary in order to obtain ambient data and identify potential sources. Groundwater and leachate samples will be collected at the Site from existing wells with low flow sampling bladder pumps. Proposed sample locations are listed in Table 2 and shown on Figure 3. Surface water samples will be collected as grab samples during the lower period of an ebb tide when surface water is flowing away from the edges of the landfill. Total and dissolved fractions of selenium and the other CAM 17 metals will be collected; dissolved samples will be filtered using 0.45 µm filters in the field. A duplicate sample at each location will be collected for total and dissolved selenium analysis. Samples will also be collected for nitrate/nitrite, major ion, and stable isotope analyses. Appendix A provides sampling and handling requirements and containers as well as general cost information for the water samples. Appendix B provides specific sampling and handling requirements for stable isotope sample collection. Field parameters will be measured during sampling and will include a measure of redox (dissolved oxygen [as mg/L] and/or oxidation-reduction potential [ORP]). Use of a flow-through cell is recommended to minimize error associated with contact with the atmosphere, which can alter dissolved oxygen content, ORP, and pH. 4.0 ANALYTICAL PROGRAM All samples will be analyzed for major ions, nitrate plus nitrite as nitrogen, and the CAM 17 metals. Analytical methods are included in Appendix A. The selenium samples will be analyzed by two different methods (EPA 6020 and EPA 200.8) and by two different laboratories to assess laboratory variations and possible method bias. In addition to the analysis described above, samples will be analyzed for stable isotopes as described in the following sections. 4.1 Stable Isotope Analyses Stable isotopes of certain elements (e.g., hydrogen, oxygen, sulfur, nitrogen, and carbon) provide additional information about geochemical transformations and sources that concentration data often cannot. Each element commonly has more than one stable isotope (i.e., varying number of neutrons) that slightly change the atomic mass of the element, which in turn changes reaction rates of the different isotopes, without changing its fundamental chemical properties. Contrary to radiogenic isotopes, stable isotopes do not decay, and therefore retain their mass through time. This constancy in elemental stable isotope chemistry and slight differences in reaction rate is commonly used to source reactions pathways for several elements in natural and industrial settings. In other words, stable isotopes provide a conservative tracer that can EXHIBIT A-4 DocuSign Envelope ID: 96EBA47B-86C9-4772-B877-2859A56AE580 January 2017 6 053-7481-16 g:\projects\palo alto lf\053-7481 (pal)\wdr workplans\selenium\selenium assessment work plan.docx provide additional information on sources and chemical processes of certain elements. These in turn provide an additional tool to assess sources of nitrate, sulfate, organic carbon, and waters. In order to provide a proper analysis, the isotopic values are compared to other isotopic values or concentration data to evaluate sources and potential geochemical transformations. For the Palo Alto Landfill investigation, stable isotope analyses will be used to identify potential geochemical pathways that may have led to increased observed selenium concentrations. Specifically, Deuterium and oxygen isotopes in water will be analyzed to determine the sources of water and potential mixing of water types, particularly between surface and groundwater. Stable isotopes in nitrate will be used to differentiate between sources of nitrate (i.e., agricultural, septic, landfill, etc.). Pyrite oxidation in the bay muds in the vicinity of the landfill, which is a potential source of selenium, will be evaluated using sulfur isotopes. Carbon stable isotopes of organic carbon will be evaluated in order to differentiate sources of dissolved organic carbon (DOC) from landfill and surrounding sources (e.g., carbon rich bay muds). 4.2 Suggested Laboratory Facilities for Non-Standard Analyses Stable isotope analyses are non-standard analyses at industrial labs, but are commonly used in academic research at universities. The Stable Isotope Laboratory at the University of California – Davis is world renowned for high quality analyses and are consistently used by academic and industrial projects, alike. Golder has often submitted samples to their facility on several occasions and recommends that nitrate, water, and DOC stable isotope samples be submitted to their laboratory facility. Nitrate stable isotopes require an appointment to submit samples ahead of time. For sulfur stable isotopes, Golder has used the Environmental Isotope Laboratory at the University of Arizona on several projects, and recommends that samples for this isotope be submitted to that facility. Appendix B provides sample requirements for isotope samples, however, specific requirements are provided on the laboratory websites, which should be used as a reference. 4.3 Post Sampling Data Analysis Data analysis will be performed using collected data in a phased approach. A geochemical characterization of the different water types will be conducted that will include piper plots of the data, Pourbaix diagrams (i.e., redox state potential [Eh] and pH diagrams), and mineral stability diagrams will be developed with the goal of identifying the unique character of each water type. Summary statistics will also be performed to provide an overview of the data and characterize the distribution of the data. Simple geochemical modeling (e.g., PHREEQC or Geochemist’s Workbench) will be performed to quantify elemental speciation and potential mineral stability in each water type. Based on statistical distribution of the data, groups of waters based on similar chemical characteristics may be consolidated in order to simplify the analysis. Stable isotope data will be evaluated to understand potential water and elemental sources and geochemical EXHIBIT A-4 DocuSign Envelope ID: 96EBA47B-86C9-4772-B877-2859A56AE580 January 2017 7 053-7481-16 g:\projects\palo alto lf\053-7481 (pal)\wdr workplans\selenium\selenium assessment work plan.docx transformations. Additional, more complicated analyses will be performed as needed (e.g., principal components analysis). Additionally, historical selenium data collected to date will be evaluated for laboratory procedures and potential bias based on the varying methodologies used to measure selenium concentrations. The evaluation will look for changes in concentration that correlate with changes in sampling and analytical methodology. Specifically, the original data sets will be evaluated using the EPA data validation and verification methodology for environmental samples. Moreover, the lab methods will be evaluated for application to the samples collected and recommendations for data use will be provided. EXHIBIT A-4 DocuSign Envelope ID: 96EBA47B-86C9-4772-B877-2859A56AE580 20-foot Detection Monitoring 40-foot Detection Monitoring Leachate G-9/88 G-13/88 G-14/88 G-16/88 G-17/88 G-19 G-1A G-3A G-8/88 G-10/88 G-12/88 G-15/88 G-20 LP-1 12/17/1996 <0.050 <0.050 <0.050 <0.050 <0.050 <0.050 <0.050 <0.050 <0.050 <0.050 <0.050 <0.050 <0.050 11/ 4/1999 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 3/17/2000 <0.005 9/29/2000 <0.005 11/ 2/2000 <0.005 0.024 <0.005 0.009 <0.005 0.006 0.074 <0.005 0.078 0.064 0.011 0.005 0.017 3/23/2001 <0.005 9/21/2001 <0.005 11/ 1/2001 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 0.007 <0.005 3/26/2002 <0.005 8/ 9/2002 <0.005 11/26/2002 0.16 0.20 0.21 0.18 0.16 0.14 0.11 0.19 0.23 0.16 0.17 0.17 0.16 3/21/2003 <0.005 9/13/2003 <0.005 11/ 5/2003 <0.020 <0.020 <0.020 <0.020 <0.020 <0.020 <0.020 <0.020 <0.020 <0.020 <0.020 <0.020 <0.020 9/24/2004 <0.005 11/16/2004 <0.050 <0.100 <0.050 <0.050 <0.050 <0.100 <0.050 <0.100 <0.100 <0.100 <0.100 <0.050 <0.100 3/25/2005 <0.010 2/17/2006 <0.002 3/16/2007 <0.014 9/28/2007 0.050 4/ 3/2008 0.030 9/ 8/2008 0.059 3/ 3/2009 0.029 7/16/2009 0.075 11/11/2009 0.19 0.23 0.23 0.10 0.12 0.16 0.19 0.23 0.27 0.21 0.21 0.16 0.23 2/12/2010 0.060 8/18/2010 0.074 3/ 1/2011 0.19 9/23/2011 0.160 2/21/2012 0.096 8/22/2012 0.140 2/5/2013 0.076 8/8/2013 0.097 3/5/2014 0.053 9/16/2014 0.110 12/ 9/2014 0.98 0.69 0.28 0.53 0.49 0.55 0.76 0.90 1.0 1.0 0.41 0.46 0.94 2/4/2015 0.092 8/11/2015 0.068 2/23/2016 0.081 5/19/2016 0.25 0.41 0.32 0.18 0.19 0.26 0.30 0.32 0.33 0.28 0.27 0.23 0.31 0.12 12/15/2016 0.35 0.57 0.52 0.33 0.51 0.32 0.40 0.47 0.49 0.44 0.50 0.38 0.36 0.31 Detected concentration Maximum value for that event Table 1 Selenium Concentrations (mg/L) in Groundwater and Leachate Palo Alto Landfill EXHIBIT A-4 DocuSign Envelope ID: 96EBA47B-86C9-4772-B877-2859A56AE580 Groundwater Monitoring Wells 20-Foot Sand:G-9/88, G-13/88, G-14/88 40-Foot Sand:G-1A, G-3A, G-8/88, G-10/88, G-12/88, G-15/88, and G-20 Leachate Piezometers GR-7, GR-16, and GR-22 Leachate Extraction Wells E-5, E-19, and E-33 Leachate Outfall LP-1 Surface Water Locations Mayfield Slough:1 in the former Yacht Harbor 1 at the northeastern corner of the Landfill 1 along the eastern side of the Landfill 1 along the southeastern edge of the Landfill Matadero Creek:1 along Matadero Creek at the southern end of the Landfill Emily Renzel Marsh Area:1 west of LP-1 Table 2 Proposed Selenium Evaluation Sample Locations Palo Alto Landfill EXHIBIT A-4 DocuSign Envelope ID: 96EBA47B-86C9-4772-B877-2859A56AE580 0 1 i n 053-7481-16 FIGURE 2016-07-21 KMM KMM TLV TLV 1 PALO ALTO LANDFILLCITY OF PALO ALTO PALO ALTO LANDFILL SANTA CLARA COUNTY, CALIFORNIA SITE LOCATON TITLE PROJECT NO.REV. PROJECTCLIENT IF T H I S M E A S U R E M E N T D O E S N O T M A T C H W H A T I S S H O W N , T H E S H E E T S I Z E H A S B E E N M O D I F I E D F R O M : A N S I A CONSULTANT PREPARED DESIGNED REVIEWED APPROVED YYYY-MM-DD Pa t h : \ \ s u n n y v a l e \ d a t a \ P r o j e c t s \ P a l o A l t o L F \ 0 5 3 - 7 4 8 1 ( P A L ) \ F i g u r e s \ | F i l e N a m e : S i t e L o c a t i o n . d w g EXHIBIT A-4 DocuSign Envelope ID: 96EBA47B-86C9-4772-B877-2859A56AE580 PALO ALTO LANDFILL SELENIUM WORKPLAN CITY OF PALO ALTO PALO ALTO LANDFILL SANTA CLARA COUNTY, CALIFORNIA SELENIUM CONCENTRATION DISTRIBUTION (mg/L) 500250 FEET 0 SCALE EXPLANATION Groundwater monitoring well monitoring 20-foot sand Groundwater monitoring well monitoring 40-foot sand Leachate piezometer Highest historical leachate concentrations Topographic base map prepared for the City of Palo Alto by Mira Solutions, Inc., Union City, CA, using photogrammetric techniques. Aerial photography: April 4, 2016. IF T H I S M E A S U R E M E N T D O E S N O T M A T C H W H A T I S S H O W N , T H E S H E E T S I Z E H A S B E E N M O D I F I E D F R O M : A N S I A CONSULTANT DESIGN PREPARED REVIEW APPROVED YYYY-MM-DD TITLE PROJECT No.Rev. PROJECTCLIENT Path: \\sunnyvale\data\Projects\Palo Alto LF\053-7481 (PAL)\Figures\ | File Name: plo.dwg 0 1 i n 053-7481-16 FIGURE 2 2016-11-29 KMM KMM TLV TLV EXHIBIT A-4 DocuSign Envelope ID: 96EBA47B-86C9-4772-B877-2859A56AE580 PALO ALTO LANDFILL SELENIUM WORKPLAN CITY OF PALO ALTO PALO ALTO LANDFILL SANTA CLARA COUNTY, CALIFORNA PROPOSED WATER QUALITY SAMPLING LOCATIONS 500250 FEET 0 SCALEEXPLANATION Groundwater monitoring well monitoring (20-foot sand) Groundwater monitoring well monitoring (40-foot sand) Leachate piezometer Leachate extraction well GR-21 and GR-22 are replacements for GR-4A and E-27P Topographic base map prepared for the City of Palo Alto by Mira Solutions, Inc., Union City, CA, using photogrammetric techniques. Aerial photography: April 4, 2016. IF T H I S M E A S U R E M E N T D O E S N O T M A T C H W H A T I S S H O W N , T H E S H E E T S I Z E H A S B E E N M O D I F I E D F R O M : A N S I A CONSULTANT DESIGN PREPARED REVIEW APPROVED YYYY-MM-DD TITLE PROJECT No.Rev. PROJECTCLIENT Path: \\sunnyvale\data\Projects\Palo Alto LF\053-7481 (PAL)\Figures\ | File Name: GW_MONITORING NETWORK_2016 topo_for workplan.dwg 0 1 i n 053-7481-16 FIGURE 3 2016-11-28 KMM KMM TLV TLV * Proposed groundwater and leachate sample location Proposed surface water sample location EXHIBIT A-4 DocuSign Envelope ID: 96EBA47B-86C9-4772-B877-2859A56AE580 MEASUREMENT VOL. REQ. (ml)BOTTLE SIZE CONTAINER PRESERVATIVE HOLDING TIME METHOD Estimated Cost for Non-Standard Analyses Major Ions (Ca, Na, K, Mg, Alkalinity, SO4, Cl)500 500 Polyethylene, Glass Filter on site, cool to 4oC 14 days SM 2320B, EPA 300.0, EPA 200.7 $50 per sample Nitrate + Nitrite (as N)500 500 Polyethylene, Glass Filter on site, cool to 4oC, H2SO4 to pH< 2 28 days EPA 353.2 or EPA 300.0 $10 per sample Dissolved Metals (Sb, As, Ba, Be, Cd, Cr, Co, Cu, Pb, Hg, Mn, Ni, Se, Ag, Tl, Sn, V, Zn)500 500 Polyethylene, Glass Filter on site, cool to 4oC, HNO3 to pH<2 180 days EPA 6020B $125 per sample Total Metals (Sb, As, Ba, Be, Cd, Cr, Co, Cu, Pb, Hg, Mn, Ni, Se, Ag, Tl, Sn, V, Zn)500 500 Polyethylene, Glass Cool to 4oC, HNO3 to pH<2 180 days EPA 6020B $125 per sample Nitrate Stable Isotopes (δ15N and δ18O) 60 60 Polyethylene Filter on Site, leave a little head space, store/ship frozen, ship to UCD SIF at appointment only 180 - 360 days UCD SIF Method $36 per sample Water Stable Isotopes (D/H and δ18O)30 30 Polyethylene, Scintillation Vials Filter on Site, leave no headspace, cool to 4oC, keep in dark 90 days UCD SIF Method $18 - $30 per sample Organic Carbon Stable Isotope (δ13C)60 60 Polyethylene Filter on Site, leave some head space and freeze ASAP after sample collection, ship frozen 30 days UCD SIF Method $26.50 per sample Sulfate-Sulfur Stable Isotope (δ34S)100 100 Polyethylene Filter on Site, leave no headspace, cool to 4oC, keep in dark 90 days UA EIL Method $34 + $10 for Sample prep Note: Volume requirements, container types, preservatives, and holding times may vary. Palo Alto Landfill Sample Containers, Volumes, Preservatives, and Holding Times Appendix A EXHIBIT A-4 DocuSign Envelope ID: 96EBA47B-86C9-4772-B877-2859A56AE580 9/19/2016 Stable Isotope Facility http://stableisotopefacility.ucdavis.edu/docsamplepreparation.html 1/2 Analysis Pricing Sample Preparation Tips Sample Submission ANALYTICAL SERVICES Carbon and Nitrogen in Solids Oxygen and Hydrogen in Solids Sulfur in Solids Oxygen and Hydrogen of Water Dissolved Organic Carbon (DOC) in Water Dissolved Inorganic Carbon (DIC) in Water Methane (CH4) in Gas Carbon Dioxide (CO2) in Gas Nitrogen (N2) and/or Nitrous Oxide (N2O) in Gas Nitrate (NO3) in water CompoundSpecific Stable Isotope Analysis (CSIA) BILLING PEOPLE GALLERY ABOUT Dissolved Organic Carbon (DOC) Sample Preparation For 13C of DOC We recommend collecting 30mL of sample in 40 mL IChem 200 series glass vials and shipping immediately after collection. If samples need to be stored for more than a few days, collect samples in 50 mL polypropylene centrifuge tubes and freeze until ready to ship. Be sure to leave some headspace to avoid cracking the centrifuge tubes during freezing. Prior to shipping, thaw samples and transfer to IChem vials. If you prefer, you can send the frozen samples in centrifuge tubes and we will transfer them to IChem vials for an additional cost of $2.50 per sample. Preserving Samples To avoid changes in isotopic value or concentration after collection, samples should be sterilized to reduce biological activity. The SIF will not accept samples preserved with mercuric chloride (HgCl2). We recommend that samples be sterilized by filtration (0.2 micron or finer media) or poisoned with zinc chloride (ZnCl2) (add 10 µl of 50% w/v ZnCl2 per milliliter of water sample). If you are not concerned about biological activity, you may still want to filter the samples to remove particulates, as all organic carbon will be converted to CO2 during the chemical oxidation. Glass fiber filters, with a nominal pore size of 0.7um, are frequently used for this purpose. Enriched / Tracer Experiment Samples We do not accept DOC samples above 3700 per mil (5 atom %). For all enriched samples, please include an estimated enrichment in your sample list. Samples over 5at% will not be analyzed. Saline Samples The SIF does not accept saline water samples for DOC in water at this time. Samples up to a salinity of 20 can be accepted, provided the DOC concentration is greater than 1 ppm. Supplies Manufacturer / Part#Description Unit IChem / S2360040 or SB360040 200 series vials, 40 mL open top cap, 0.125" septum 72/PK or 144/PK VWR / 89093856 or 89093870 TraceClean 40 mL vials, Processed (PC), OpenTop, Amber or Clear 72/PK Shipping Wrap individual glass vials to protect them during shipping. Group samples in Ziploc bags to help minimize leaking/wet boxes during shipping. Carefully package samples in an insulated box or cooler with dry ice or ice blocks. Coolers will not be returned. Please complete and submit the online Analysis Order Form and Sample List for your samples. Include a printed copy of these forms with your samples. The SIF uses this form to track your samples and to contact you regarding receipt of samples, data, and invoicing. For mixed analysis requests, we require the completion of a separate form for each type of analysis. EXHIBIT A-4 DocuSign Envelope ID: 96EBA47B-86C9-4772-B877-2859A56AE580 9/19/2016 Stable Isotope Facility http://stableisotopefacility.ucdavis.edu/docsamplepreparation.html 2/2 Storage and Disposal Samples will be stored by SIF for 3 months postanalysis and then discarded. Please review your results during this 3month window. References St. Jean, G. 2003. Automated quantitative and isotopic (13C) analysis of dissolved inorganic carbon and dissolved organic carbon in continuous flow using a total organic carbon analyzer. Rapid Communications in Mass Spectrometry 17: 419428. email: sif@ucdavis.edu | phone: 5307528100 | fax: 5307524361 UC Davis Stable Isotope Facility | Department of Plant Sciences One Shields Avenue | Davis, California, 95616 | USA EXHIBIT A-4 DocuSign Envelope ID: 96EBA47B-86C9-4772-B877-2859A56AE580 9/19/2016 Stable Isotope Facility http://stableisotopefacility.ucdavis.edu/18owatersamplepreparation.html 1/2 Analysis Pricing Sample Preparation Tips Sample Submission ANALYTICAL SERVICES Carbon and Nitrogen in Solids Oxygen and Hydrogen in Solids Sulfur in Solids Oxygen and Hydrogen of Water Dissolved Organic Carbon (DOC) in Water Dissolved Inorganic Carbon (DIC) in Water Methane (CH4) in Gas Carbon Dioxide (CO2) in Gas Nitrogen (N2) and/or Nitrous Oxide (N2O) in Gas Nitrate (NO3) in water CompoundSpecific Stable Isotope Analysis (CSIA) BILLING PEOPLE GALLERY ABOUT Oxygen (18O) and Hydrogen (D/H) Water Sample Preparation and Organization The standard volume for water samples is 11.4 mL in a 2 mL GC vial. Contact the SIF about low volume samples. Use vials with a writeon patch or use clear tape and permanent marker to label vials. Samples should be kept refrigerated and in the dark for longterm storage. Use minimal headspace for shipping and storing water samples. Additional preservation is not necessary. We do not accept samples preserved with mercuric chloride (HgCl2) or poisoned with sodium azide (NaN3). Samples will be stored for 3 months postanalysis and then discarded. Please review your data within this window. Supplies Submit samples in standard autosampler vials (volume: 2 mL, 12 mm O.D. x 32 mm length) with widemouth 10425 screw caps and double coated (PTFE/silicon/PTFE) septa. Samples not submitted in autosampler vials will be charged a transfer fee (see Pricing). For lowvolume samples (less than 250 µL), use the appropriate polypropylene insert molded vials (C401311 and C401360A, see below). Please contact us prior to sending lowvolume samples. The following is a list of the vials we use. Other suitable vials are available from a variety of suppliers. We suggest screwtop vials with writeon labels. Only 10mm closures are acceptable. Manufacturer / Part#Description National Scientific / C40101W Vials, 2 mL, 10 mm screw thread, clear glass, writeon patch National Scientific / C401040A Screw caps with septa, 10 mm (PTFE/Silicone/PTFE) National Scientific / C401311 250 µL, polypropylene, 12x32mm, conical, 8425 screw thread vial (for samples < 100 µL) National Scientific / C401360A Screw caps with septa, for 8425 vials, (PTFE/Silicone) National Scientific / C401225 Storage rack for 50 vials, polypropylene, without lid National Scientific / C401125 Storage rack for 100 vials, polystyrene, with lid Organizing samples In order to use the correct reference waters, please group water samples into the following classes: Group δD/H δ18O Natural Abundance Up to 60 per mil Up to 6 per mil Low Enrichment 60 to 1690 per mil (0.042 at%) 6 to 263 per mil (0.25 at%) High Enrichment Over 1690 per mil (>0.042 at%) not accepted Over 263 per mil (>0.25 at%) not accepted EXHIBIT A-4 DocuSign Envelope ID: 96EBA47B-86C9-4772-B877-2859A56AE580 9/19/2016 Stable Isotope Facility http://stableisotopefacility.ucdavis.edu/18owatersamplepreparation.html 2/2 For tracer studies, estimates on isotope values are required and samples must be organized by increasing enrichment. Saline samples must be clearly marked with an estimate of the salinity. Organize saline samples in order of increasing salinity. Units of ppt or mS/cm are preferred. Organize water samples in order of increasing conductivity. Turbid water samples or water samples containing precipitate must be filtered prior to analysis. If SIF determines a water sample requires filtering, a $5.00 fee will be charged per sample for this service. The SIF only analyzes samples with a pH between 5 and 9. Samples outside this range must be neutralized prior to shipment to the SIF. Shipping Carefully package racks of vials in ziplock bags, small boxes, or their original boxes. Then package these sets in a larger sturdy box with styrofoam peanuts or bubble wrap. Make sure the samples are very secure; loose vials can break during shipping. If samples must be shipped with a refrigerant, be sure to insulate your samples from freezing. Avoid using dry ice as a refrigerant, as samples in direct contact with a refrigerant like dry ice will crack during shipping. Coolers will not be returned. Please complete and submit the online Analysis Order Form and Sample List for your samples. Also, be sure to include a printed copy with your samples. The SIF uses this form to track your samples and to contact you regarding receipt of samples, data, and invoicing. For mixed analysis requests, we require the completion of a separate form for each type of analysis. email: sif@ucdavis.edu | phone: 5307528100 | fax: 5307524361 UC Davis Stable Isotope Facility | Department of Plant Sciences One Shields Avenue | Davis, California, 95616 | USA EXHIBIT A-4 DocuSign Envelope ID: 96EBA47B-86C9-4772-B877-2859A56AE580 9/19/2016 Stable Isotope Facility http://stableisotopefacility.ucdavis.edu/no3samplepreparation.html 1/2 Analysis Pricing Sample Preparation Tips Sample Submission ANALYTICAL SERVICES Carbon and Nitrogen in Solids Oxygen and Hydrogen in Solids Sulfur in Solids Oxygen and Hydrogen of Water Dissolved Organic Carbon (DOC) in Water Dissolved Inorganic Carbon (DIC) in Water Methane (CH4) in Gas Carbon Dioxide (CO2) in Gas Nitrogen (N2) and/or Nitrous Oxide (N2O) in Gas Nitrate (NO3) in water CompoundSpecific Stable Isotope Analysis (CSIA) BILLING PEOPLE GALLERY ABOUT Nitrate (NO3) in Water Sample Preparation Appointments are required for the bacterial denitrifier preparation. Contact us prior to your sampling date, as we are often booked up to 3 months in advance. Nitrate in water samples for bacterial denitrifier preparation by the SIF should be filtered (<0.45 micron pore, preferably 0.1 micron), stored frozen, and shipped frozen. Use 3060 mL nitratefree, freezable, widemouthed, screwtop containers. A minimum of 10 mL of water sample is required, with 2030 mL preferred. Samples requiring extensive handling by the SIF (e.g., filtering) will be charged incidental fees per sample. Accurate nitrate concentrations are required for all samples. Please specify if your concentrations are NO3 vs. NO3N, μM vs. mg/L, etc. If this information is not available, please allow the SIF to refer you to an analytical facility that can determine the concentration for you. Required minimum concentration is 2 μM nitrate. Samples with missing or inaccurate nitrate concentrations will be charged for reruns and take longer to process. The bacterial denitrifier method does not discriminate between nitrate (NO3) and nitrite (NO2) nitrogen. Samples expected to contain nitrite should be prepared according to Granger and Sigman (2009) prior to submission to the SIF. Special Sample Types For enriched samples / tracer experiments, please contact the SIF prior to your experiment. The SIF no longer accepts customerprepared nitrate in water samples. Due to the nature of bacterial denitrification preparation and analysis, we cannot offer appropriate quality assurance unless we prepare the samples (and standards) ourselves. For a more detailed description of the NO3 in water preparation method, please see the denitrifier articles in the references section. We do accept KCl soil extracts and TDN digests. Please contact us for details and special requirements. For ammonium, most of our clients diffuse from solution onto acidified discs. The resulting disc is then submitted and analyzed as a solid sample. For details on performing the diffusion method, please see Holmes, et al (1998) in the references section. Supplies Manufacturer / Part# Description Unit Wheaton / 209545 LeakResistant WideMouth HDPE Bottles, 30mL, Natural w/ cap Case of 72 Wheaton / 209546 LeakResistant WideMouth HDPE Bottles, 60mL, Natural w/ cap Case of 72 Wheaton / 209626 LeakResistant WideMouth HDPE Bottles, 60mL, Amber w/ cap Case of 72 Freezing and Shipping Samples At low temperatures, both polypropylene and polystyrene become brittle and are prone to cracking. Please use only polyethylene or polycarbonate containers. Make sure the containers are nitratefree. Leave enough headspace to account for expansion during freezing, and prechill your samples in EXHIBIT A-4 DocuSign Envelope ID: 96EBA47B-86C9-4772-B877-2859A56AE580 9/19/2016 Stable Isotope Facility http://stableisotopefacility.ucdavis.edu/no3samplepreparation.html 2/2 a refrigerator for the first 1224 hours prior to freezing. Once frozen, carefully pack small sets of samples in ziplock bags or small boxes with dividers. Pack these sets in a larger hardwalled cooler or Styrofoam insulated shipping kit with packing peanuts or bubble wrap. Make sure the samples are well cushioned on all sides, as loose bottles can break during shipping. Do not use foamonly coolers or cardboardonly boxes for the exterior shipping container; these containers will disintegrate due to condensation and hard impacts when tossed by couriers. Keep the entire shipment frozen until time to ship. "Prechilling" your cooler will extend refrigeration time. We recommend blue ice blocks, cold packs, or ice blankets for packages sent by Overnight or 1day delivery. Dry ice is advisable for delivery times exceeding 2 days. Pack about 1520 pounds of dry ice for the first 24 hours of transit, plus an additional 510 pounds of dry ice for each additional day of transit. Fill any remaining “air space” in the cooler with newspaper or other filler to slow sublimation and protect against damage. Ship your samples by the fastest available method to arrive at the SIF midweek (Tuesday through Thursday). If you would like your cooler returned, please include a prepaid shipping label. We recommend saving a duplicate set of samples in case of sample loss, whether due to shipping loss or cracked vials. Please complete and submit the online Analysis Order Form and Sample List for your samples. Include nitrate concentrations for all samples for bacterial denitrification preparation by the SIF. Samples with missing or inaccurate nitrate concentrations will be charged for reruns and take longer to process. Be sure to include a printed copy of both forms with your samples. The SIF uses these forms to track your samples and to contact you regarding sample receipt, data, and invoicing. For mixed analysis requests, you must complete a separate set of forms for each type of analysis. Sample Storage and Retention by the SIF The SIF will store your samples in the freezer. Due to limited freezer space, please ship your samples to arrive only 1 to 3 weeks prior to your appointment. The SIF will send an email reminder approximately 4 to 6 weeks prior to your appointment. After analysis and reruns are complete, samples will be stored by SIF for 2 months and then discarded. Please review your results during this 2month window. References D. M. Sigman, K. L. Casciotti, M. Andreani, C. Barford, M. Galanter, and J. K. Böhlke. 2001. A bacterial method for the nitrogen isotopic analysis of nitrate in seawater and freshwater. Anal. Chem. 73: 41454153. K. L. Casciotti, D. M. Sigman, M. Galanter Hastings, J. K. Böhlke, and A. Hilkert. 2002. Measurement of the oxygen isotopic composition of nitrate in seawater and freshwater using the denitrifier method. Anal. Chem. 74: 49054912. J. Granger and D.M. Sigman. 2009. Removal of nitrite with sulfamic acid for nitrate N and O isotope analysis with the denitrifier method. Rapid Comm. Mass Spectrom. 23: 37533762. R. M. Holmes, J. W. McClelland, D. M. Sigman, B. Fry, and B. J. Peterson. 1998. Measuring 15NNH4+ in marine, estuarine, and fresh waters: An adaptation of the ammonia diffusion method for samples with low ammonium concentrations. Mar. Chem. 60: 235243. email: sif@ucdavis.edu | phone: 5307528100 | fax: 5307524361 UC Davis Stable Isotope Facility | Department of Plant Sciences One Shields Avenue | Davis, California, 95616 | USA EXHIBIT A-4 DocuSign Envelope ID: 96EBA47B-86C9-4772-B877-2859A56AE580 9/19/2016 Environmental Isotope Laboratory | Services | UA Geosciences http://www.geo.arizona.edu/node/153 1/5 University of Arizona About Us People For Grad Students For Undergrads Research Areas Events & Programs Alumni Photos Facebook Quick Links Industry Recruiting 2016 Where in the World is UA Geosciences? George H. Davis Undergraduate Research Fund Research Facilities, Programs & Resources News & Archives School of Earth & Environmental Sciences College of Science UA Mineral Museum UAConnect Email Course Pages Mime Mail Example New Publications Resilience of the Asian atmospheric circulation shown by Paleogene dust provenance Licht, A, et al. EXHIBIT A-4 DocuSign Envelope ID: 96EBA47B-86C9-4772-B877-2859A56AE580 9/19/2016 Environmental Isotope Laboratory | Services | UA Geosciences http://www.geo.arizona.edu/node/153 2/5 See All Geosciences Administration Departmental Forms Departmental Computing Environmental Isotope Laboratory | Services Service analyses for internal and external users include measurement of natural levels of tritium in water, stable isotope analyses of water, carbonates, brines, sulfide and sulfate minerals. The Radiocarbon Laboratory has closed. For radiocarbon dating, please contact the NSFArizona Accelerator facility. Analytical Service Rates for 2016 Analytical Method Descriptions C and N isotopes in organics, soils etc. d15N and d13C, as well as carbon and nitrogen content were measured on a continuousflow gasratio mass spectrometer (Finnigan Delta PlusXL) coupled to an elemental analyzer (Costech). Samples were combusted in the elemental analyzer. Standardization is based on acetanilide for elemental concentration, NBS22 and USGS24 for d13C, and IAEAN1 and IAEAN2 for d15N. Precision is better than ± 0.10 for d13C and ± 0.2 for d15N (1s), based on repeated internal standards. Carbonate isotopes d18O and d13C of carbonates were measured using an automated carbonate preparation device (KIELIII) coupled to a gasratio mass spectrometer (Finnigan MAT 252). Powdered samples were reacted with dehydrated phosphoric acid under vacuum at 70°C. The isotope ratio measurement is calibrated based on repeated measurements of NBS19 and NBS18 and precision is ± 0.1 ‰ for d18O and ±0.08‰ for d13C (1sigma). H isotopes in cellulose and minerals EXHIBIT A-4 DocuSign Envelope ID: 96EBA47B-86C9-4772-B877-2859A56AE580 9/19/2016 Environmental Isotope Laboratory | Services | UA Geosciences http://www.geo.arizona.edu/node/153 3/5 d D was measured on a continuousflow gasratio mass spectrometer (Thermo Electron Delta V). Samples were combusted at 1400 °C using an ThermoQuest Finnigan TCEA (Thermal combustion elemental analyzer) coupled to the mass spectrometer. Standardization is based on a linear calibration curve obtained by measuring three materials NIST SRM 8540 (65.7‰), IAEA CH7 (110.3‰) and our house standard benzoic acid (87.6‰) in each set of analyses. Precision is better than ± 2.5 per mil on the basis of repeated internal standards. H isotopes in organics with exchangeable hydrogen Samples were equilibrated with ambient water vapor in laboratory air with tracer standards (swan feather). They are then dried with P2O5 for at least 6 hours. d D was measured on a continuousflow gasratio mass spectrometer (Thermo Electron Delta V). Samples were combusted with excess C at 1400 °C using an ThermoQuest Finnigan TCEA (Thermal combustion elemental analyzer) coupled to the mass spectrometer. Standardization is based on the calibrated house standard benzoic acid (87.6‰) and Hexatriacontane (247, University of Indiana) in each set of analyses. A value of 1.120 is used for the fractionation between water vapor and exchangeable hydrogen in calculating the nonexchangeable dD value. Precision is better than ± 2.5 per mil on the basis of repeated internal standards. O and H isotopes in water d D and d18O were measured on a gassource isotope ratio mass spectrometer (Finnigan Delta S). For hydrogen, samples were reacted at 750°C with Cr metal using a Finnigan H/Device coupled to the mass spectrometer. For oxygen, samples were equilibrated with CO2 gas at approximately 15°C in an automated equilibration device coupled to the mass spectrometer. Standardization is based on international reference materials VSMOW and SLAP. Precision is 0.9 per mil or better for d D and 0.08 per mil or better for d18O on the basis of repeated internal standards. S isotopes in sulfates and sulfides d34S was measured on SO2 gas in a continuousflow gasratio mass spectrometer (ThermoQuest Finnigan Delta PlusXL). Samples were combusted at 1030 deg. C with O2 and V2O5 using an elemental analyzer (Costech) coupled to the mass spectrometer. Standardization is based on international standards OGS1 and NBS123, and several other sulfide and sulfate materials that have been compared between laboratories. Calibration is linear in the range 10 to +30 per mil. Precision is estimated to be ± 0.15 or better (1s), based on repeated internal standards. C isotopes in DIC d13C of DIC was measured on a continuousflow gasratio mass spectrometer (ThermoQuest Finnigan Delta PlusXL) coupled with a Gasbench automated sampler (also manufactured by Finnigan). Samples were reacted for > 1 hour with phosphoric acid at room temperature in Exetainer vials previously flushed with He gas. Standardization is based on NBS19 and NBS18 and precision is ±0.30‰ or better (1sigma). EXHIBIT A-4 DocuSign Envelope ID: 96EBA47B-86C9-4772-B877-2859A56AE580 9/19/2016 Environmental Isotope Laboratory | Services | UA Geosciences http://www.geo.arizona.edu/node/153 4/5 O isotopes in sulfate d18O of sulfate was measured on CO gas in a continuousflow gasratio mass spectrometer (Thermo Electron Delta V). Samples were combusted with excess C at 1350 °C using a thermal combustion elemental analyzer (ThermoQuest Finnigan) coupled to the mass spectrometer. Standardization is based on international standard OGS1. Precision is estimated to be ± 0.3 per mil or better (1s), based on repeated internal standards. Tritium Tritium was measured by liquid scintillation spectrometry on samples that were first distilled to remove non volatile solutes, and then enriched by electrolysis by a factor of about 9. Enriched samples were mixed 1:1 with Ultimagold Low Level Tritium (R) cocktail, and counted for 1500 minutes in a Quantulus 1220 Spectrometer in an underground counting laboratory at the University of Arizona. The detection limit under these conditions is 0.6 TU. Standardization is relative to NIST SRM 4361C, and water from Agua Caliente Spring in Tucson basin is used to determine background. O isotopes in organics d18O of cellulose was measured on a continuousflow gasratio mass spectrometer (Thermo Electron Delta PlusXL). Samples were combusted with excess C at 1350 °C using a thermal combustion elemental analyzer (ThermoQuest Finnigan) coupled to the mass spectrometer. Standardization is based on international standards IAEA601, IAEA602 and OGS1. Precision is estimated to be ± 0.3 per mil or better (1s), based on repeated internal standards. N isotopes in bulk DIN d15N was measured on bulk residual salt from the gentle evaporation of water to dry; this represents bulk DIN of the sample. Measurements were made using a continuous flow gasratio mass spectrometer (Finnigan Delta PlusXL) coupled to an elemental analyzer (Costech). Samples were combusted in the elemental analyzer. Standardization is based on IAEAN1 and IAEAN2 for d15N. The IAEA standards were used to calibrate d15N of the laboratory working standard, acetanilide. Precision is better than ± 0.2 for d15N (1s), based on repeated internal standards. Contact David Dettman Data Repository Environmental Isotope Laboratory Home EXHIBIT A-4 DocuSign Envelope ID: 96EBA47B-86C9-4772-B877-2859A56AE580 9/19/2016 Environmental Isotope Laboratory | Services | UA Geosciences http://www.geo.arizona.edu/node/153 5/5 Department of Geosciences The University of Arizona 1040 E. 4th Street Tucson, AZ 85721 Phone: 5206216000 Fax: 5206212672 CAS Login You will be redirected to the secure CAS login page. Log in using CAS Course Pages University of Arizona Copyright 2016 © Arizona Board of Regents EXHIBIT A-4 DocuSign Envelope ID: 96EBA47B-86C9-4772-B877-2859A56AE580 EXHIBIT “B” SCHEDULE OF PERFORMANCE AMENDMENT NO. 3 CONSULTANT shall perform the Services so as to complete each milestone within the date specified bellow. The time to complete each milestone may be increased or decreased by mutual written agreement of the project managers for CONSULTANT and CITY so long as all work is completed within the term of the Agreement. CONSULTANT shall provide a detailed schedule of work consistent with the schedule below within 2 weeks of receipt of the notice to proceed. Milestones Completion Date 1. Draft report due May 1, 2018 2. Draft report meeting May 8, 2018 3. Final report due June 1, 2018 DocuSign Envelope ID: 96EBA47B-86C9-4772-B877-2859A56AE580 EXHIBIT “C-3” COMPENSATION AMENDMENT NO. 3 The CITY agrees to compensate the CONSULTANT for professional services performed in accordance with the terms and conditions of this Agreement, and as set forth in the budget schedule below. Compensation shall be calculated based on the hourly rate schedule attached as Exhibit C-1 up to the not to exceed budget amount for each task set forth below. CONSULTANT shall perform the tasks and categories of work as outlined and budgeted below. The CITY’s Project Manager may approve in writing the transfer of budget amounts between any of the tasks or categories listed below provided the total compensation for Basic Services, including reimbursable expenses, and the total compensation for Additional Services do not exceed the amounts set forth in Section 4 of this Agreement. BUDGET SCHEDULE NOT TO EXCEED AMOUNT Task 1a- Sample Collection and Analysis $7,500 Sample Collection Sample Analysis $18,500 Task 1b $10,000 Leachate Pump Testing Task 1c $32,000 Data Analysis and Report Preparation Task 1d $15,000 Optional subtask: Drill temporary wells and collect water samples Sub-total Basic Services $83,000 Reimbursable Expenses $0 Total Basic Services and Reimbursable expenses $83,000 DocuSign Envelope ID: 96EBA47B-86C9-4772-B877-2859A56AE580 Additional Services (Not to Exceed) $8,300 Maximum Total Compensation $91,300 ADDITIONAL SERVICES The CONSULTANT shall provide additional services only by advanced, written authorization from the CITY. The CONSULTANT, at the CITY’s project manager’s request, shall submit a detailed written proposal including a description of the scope of services, schedule, level of effort, and CONSULTANT’s proposed maximum compensation, including reimbursable expense, for such services based on the rates set forth in Exhibit C-1. The additional services scope, schedule and maximum compensation shall be negotiated and agreed to in writing by the CITY’s and CONSULTANT prior to commencement of the services. Payment for additional services is subject to all requirements and restrictions in this Agreement DocuSign Envelope ID: 96EBA47B-86C9-4772-B877-2859A56AE580 Certificate Of Completion Envelope Id: 96EBA47B86C94772B8772859A56AE580 Status: Completed Subject: Please DocuSign: S15156222- Amendment No 3.pdf Source Envelope: Document Pages: 52 Signatures: 2 Envelope Originator: Supplemental Document Pages: 0 Initials: 0 Cecilia Magana Certificate Pages: 2 AutoNav: Enabled EnvelopeId Stamping: Enabled Time Zone: (UTC-08:00) Pacific Time (US & Canada) Payments: 0 250 Hamilton Ave Palo Alto , CA 94301 cecilia.magana@cityofpaloalto.org IP Address: 12.220.157.20 Record Tracking Status: Original 7/17/2017 12:58:04 PM Holder: Cecilia Magana cecilia.magana@cityofpaloalto.org Location: DocuSign Signer Events Signature Timestamp William Fowler bfowler@golder.com Principal Security Level: Email, Account Authentication (None)Using IP Address: 157.208.240.5 Sent: 7/20/2017 3:37:16 PM Resent: 7/21/2017 11:11:30 AM Resent: 7/24/2017 2:16:09 PM Viewed: 7/24/2017 2:18:22 PM Signed: 7/24/2017 2:19:06 PM Electronic Record and Signature Disclosure: Not Offered via DocuSign In Person Signer Events Signature Timestamp Editor Delivery Events Status Timestamp Agent Delivery Events Status Timestamp Intermediary Delivery Events Status Timestamp Certified Delivery Events Status Timestamp Carbon Copy Events Status Timestamp Elise Sbarbori Elise.Sbarbori@CityofPaloAlto.org Security Level: Email, Account Authentication (None) Sent: 7/24/2017 2:19:08 PM Viewed: 7/24/2017 2:43:07 PM Electronic Record and Signature Disclosure: Not Offered via DocuSign margaret Adkins Margaret.Adkins@CityofPaloAlto.org Security Level: Email, Account Authentication (None) Sent: 7/24/2017 2:19:09 PM Viewed: 7/24/2017 2:19:45 PM Electronic Record and Signature Disclosure: Not Offered via DocuSign Notary Events Signature Timestamp Envelope Summary Events Status Timestamps Envelope Sent Hashed/Encrypted 7/24/2017 2:19:09 PM Certified Delivered Security Checked 7/24/2017 2:19:09 PM Envelope Summary Events Status Timestamps Signing Complete Security Checked 7/24/2017 2:19:09 PM Completed Security Checked 7/24/2017 2:19:09 PM Payment Events Status Timestamps