MONITORING REPORT, FIRST SEMESTER 2012, EVANS ROAD LANDFILL, COLUSA COUNTY, CALIFORNIA

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1 166 Eaton Road, Suite B Chico, California Phone: (530) Fax: (530) J# June 2012 Mr. Mike Azevedo Colusa County Public Works Department 1215 Market Street Colusa, CA MONITORING REPORT, FIRST SEMESTER 2012, EVANS ROAD LANDFILL, COLUSA COUNTY, CALIFORNIA Dear Mr. Azevedo: Haling & Associates (H&A) is pleased to present the attached Monitoring Report, First Semester 2012, Evans Road Landfill, Colusa County, California. Monitoring activities were performed in accordance with the Central Valley Regional Water Quality Control Board (CVRWQCB) Waste Discharge Requirements (WDR) and Monitoring and Reporting Program (MRP) No. R dated 7 June 2002, and H&A s contract with the County of Colusa contract number C10-043, dated 9 March The scope of work for the current semester included quarterly groundwater elevation measurements, quarterly landfill gas measurements from passive landfill vents, quarterly landfill gas measurements from perimeter soil gas monitoring wells, and semi-annual groundwater sampling and laboratory analysis. The enclosed report includes descriptions and results of these monitoring events. It is important to note that no violations occurred at the Evans Road Landfill during the First Semester H&A appreciates the opportunity to work with Colusa County on this important project. If you have questions or comments regarding this report or require additional information, please contact the undersigned at (530) Sincerely, HALING & ASSOCIATES Greg Haling, P.E. Principal Engineer Dave Ivy Staff Environmental Engineer Attachments: Semi-Annual Monitoring Report, First Semester 2012 (3 copies) CD-ROM: Semi-Annual Monitoring Report, First Semester 2012 Electronic spreadsheet w/ current and historical analytical data

2 CERTIFICATION This Monitoring Report, First Semester 2012, Evans Road Landfill, Colusa County, California was prepared for Colusa County Public Works under Contract Number C10-043, dated 9 March This document was prepared by Mr. Dave Ivy, Staff Environmental Engineer, and approved for release by Mr. Greg Haling, a registered Professional Engineer in the State of California. APPROVED FOR RELEASE: 6/28/12 Greg Haling, P.E. Principal Engineer

3 TABLE OF CONTENTS 1.0 INTRODUCTION PREFACE SITE DESCRIPTION SCOPE OF WORK IMPLEMENTATION OF FIELD ACTIVITIES SECOND SEMESTER FIELD ACTIVITIES AND PROCEDURES Water Elevation Measurements Groundwater Sampling Surface Water Monitoring Landfill Gas Vent Monitoring Soil Gas Well Monitoring QUALITY ASSURANCE/QUALITY CONTROL METHODS RESULTS OF SECOND SEMESTER 2011 FIELD ACTIVITIES GROUNDWATER FLOW CONDITIONS GROUNDWATER MONITORING PARAMETERS Groundwater Field Parameters Groundwater Monitoring Parameters Five-Year Constituents of Concern Quality Assurance/Quality Control SURFACE WATER CONDITIONS LANDFILL GAS MEASUREMENTS CONCENTRATION LIMITS METHODS RESULTS SUMMARY Haling and Associates i

4 TABLE OF CONTENTS (CONT.) FIGURES Figure 1 Location Map Figure 2 Site Sketch Figure 3 Groundwater Elevation Measurements Figure 4 Groundwater Potentiometric Surface Map 19 March 2012 Figure 5 Groundwater Potentiometric Surface Map 23 May 2012 TABLES Table 1 Table 2 Table 3 Table 4 Table 5 Table 6 Table 7 Table 8 Table 9 Table 10 Table 11 Table 12 Table 13 Historical Groundwater Elevation Data Groundwater Flow Direction and Gradient Groundwater Field Parameters Semi-annual Groundwater Monitoring Parameters Volatile Organic Compounds Groundwater 5-Year Constituents of Concern Groundwater 5-Year Dissolved Inorganics Groundwater Water Quality Parameters Surface Water 5-Year Dissolved Inorganics Surface Water Gas Vent Results Soil Gas Monitoring Points Volatile Organic Compounds Soil Gas Tolerance Interval Analysis APPENDICES Appendix A Appendix B Appendix C Appendix D Graphical Summaries of Groundwater Monitoring Monitoring Well Sampling Data Sheets Groundwater Hydrographs Laboratory Analytical Report and Chain of Custody Documentation Haling and Associates ii

5 First Semester 2011 Monitoring Report Evans Road Landfill 1.0 INTRODUCTION 1.1 Preface This report was prepared as a summary of results for the First Semester 2012 monitoring events at Evans Road Landfill (ERL). ERL is part of a closed waste management facility that consists of one closed Class III landfill, three closed Class II surface impoundments, and one pesticide container disposal area. While in operation, ERL was permitted to receive non-hazardous waste. ERL is currently maintained by the Colusa County Department of Public Works and is regulated by Title 27 California Code of Regulations (CCR) through Waste Discharge Requirements (WDR) Order No. R issued by the California Regional Water Quality Control Board, Central Valley Region (CVRWQCB) on 7 June Site Description The ERL site is located seven miles southwest of Williams, California, in the southern half of the northeast quarter and a portion of the southern half of the northwest quarter of Section 15, T14N, R3W, MDB&M, as shown in Figure 1. The ERL site is located within a distal portion of northeast draining alluvial fans emanating from the Coast Ranges. The geologic units underlying the ERL site consist of recent surficial alluvium to a depth of approximately 57 feet below ground surface, underlain by alluvial deposits of the Tehama Formation. Groundwater generally occurs within the Tehama Formation at depths greater than 100 feet. Five site groundwater monitoring wells (M-1A, M-1B, M-3A, M-4, and M-5) are used to monitor groundwater conditions at the ERL site. Two locations (S-1 and S-2) have been established to collect surface storm water runoff during the first significant storms of each rainfall season. Figure 2 illustrates the site layout and sampling locations. Previous interpretations of groundwater flow direction at ERL were based on water levels in well M-1, which historically displayed the highest groundwater elevations. The groundwater elevation in M-1 started out relatively low in early 1995, at approximately 150 feet below the top of the casing (btc). In late 1995, M-1 went dry. In 1996, the water level in M-1 recovered to approximately 147 feet btc. From 1996 to 2000, the water in M-1 steadily rose to approximately 136 feet btc, and then went dry again in 2001, presumably due to a 15 foot drop in water elevation in one year. The only other well that was monitored through this entire period was M-4. From 1996 to 2000, M-4 rose approximately 7 feet, and dropped approximately 2.5 feet in In July 1998, monitoring wells M-1A and M-3A were installed, and monitoring wells M-2 and M-3 were abandoned and sealed by a licensed drilling contractor. Haling and Associates 1

6 First Semester 2011 Monitoring Report Evans Road Landfill Review of water elevation data for wells M-1 and M-4, and other historical groundwater elevation data supports the opinion that M-1 was screened in a perched water-bearing zone that was not likely connected to the shallow water-bearing zone monitored by the other wells. Based on this interpretation, M-1 was abandoned and M-1B was installed in February Since the installation of wells M-1A and M-3A, the interpretation of the direction of groundwater flow has been in question. In the report entitled, Construction/Testing of Groundwater Monitoring Wells M-1A and M-3A and Abandonment of M-2 and M-3, Evans Road Landfill, (Lawrence and Associates, October 1998), Lawrence and Associates (L&A) concluded that M-1A may be screened in a deeper water bearing zone than monitoring wells M-1, M-3A, and M-4. A previous review of the L&A boring logs by Montgomery Watson Harza (MWH) found that M-1A is not deep enough to intercept the same groundwater-bearing zone as M-3A and M-4. Prior to 2003 the interpreted direction of groundwater flow was to the northeast. However, since 2003 the direction of groundwater flow at the site has been to the southwest. 2.0 SCOPE OF WORK The scope of work performed for the First Semester 2012 sampling event included the following: Groundwater: Measurement of static groundwater elevations at monitoring wells M-1A, M-1B, M-3A, M-4, and M-5 on 5 March and 23 May Purge and sampling of five groundwater monitoring wells (M-4 had insufficient water for purging) for field parameters (ph, electrical conductivity, turbidity, and temperature) and groundwater monitoring parameters on 5 March 2012 in accordance with Monitoring and Reporting Program (MRP) No. R Surface Water: Inspection of surface water sampling locations S-1 and S-2 for flow on 5 March and 23 May No flow was present at the designated locations so no samples were collected. Landfill Gas: Field measurement of landfill gas constituents on 5 March and 23 May 2012 at four sets of nested perimeter soil gas monitoring wells (GW-1 [shallow (S) and deep (D)], GW-2 [S and D], GW-3 [S and D], and GW-4 [S and D]) and seven passive landfill gas vents (V-1 through V-7). Haling and Associates 2

7 First Semester 2011 Monitoring Report Evans Road Landfill 3.0 IMPLEMENTATION OF FIELD ACTIVITIES FIRST SEMESTER Field Activities and Procedures All field activities were performed in accordance with quality assurance/quality control (QA/QC) procedures and analytical methods for ground water, surface water and soil gas as delineated in the Sample Collection and Analysis Plan for Evans Road Landfill, (H&A, 4 December 2008) Water Elevation Measurements Static groundwater elevation measurements were obtained for all site monitoring wells (M-1A, M-1B, M-3A, M-4, and M-5) during the First Semester 2012 monitoring events conducted on 5 March and 23 May Depth-to-water was measured at each groundwater monitoring well to the nearest hundredth of a foot from each top of well casing with an electrical water-level sounding probe Groundwater Sampling Groundwater samples were collected from monitoring wells M-1A, M-1B, M-3A, M-4, and M-5 on 5 March 2012 for field and laboratory analyses of semi-annual monitoring parameters. Samples were collected after a minimum of three well casing volumes were purged and measurements of groundwater field parameters had stabilized at all wells except M-4, which had insufficient water for purging. Groundwater samples were collected with Grunfos pump or disposable bailers and placed in containers provided by the contracted laboratory, stored with ice (at approximately 4º C) in coolers, and transported under standard chain-of-custody documentation to a California state-certified laboratory for analysis Surface Water Monitoring Surface water was not present at sampling locations S-1 and S-2 during the First Semester Surface water samples were last collected during the first semester Landfill Gas Vent Monitoring Monitoring is performed on the ERL passive landfill gas extraction system as detailed in the Workplan for Landfill Gas Extraction System, Evans Road Landfill, (H&A, 3 October 2005). Monitoring of the seven passive landfill gas vents is performed on a quarterly basis using an infrared gas analyzer capable of detecting methane, carbon dioxide and oxygen content Soil Gas Well Monitoring In accordance with Title 27 CCR (California Code of Regulations) Section 20925, quarterly monitoring activities are performed at four double completed perimeter soil gas monitoring wells using an infrared gas analyzer. Haling and Associates 3

8 First Semester 2011 Monitoring Report Evans Road Landfill 3.2 Quality Assurance/Quality Control Methods The QA/QC program followed by H&A and the laboratory incorporated the following field and laboratory QA/QC techniques: chain-of-custody control of samples; field duplicate sample; decontamination of field equipment between each sampling location; and laboratory methods: matrix spikes (MS); matrix spike duplicates (MSD); method blanks; laboratory control samples (LCS); and laboratory control sample duplicates (LCSD). 4.0 RESULTS OF FIRST SEMESTER 2012 FIELD ACTIVITIES In order to address concerns expressed in the CVRWQCB review letter dated 26 June 2008 and the subsequent submittal extension letter dated 14 August 2008, an electronic Excel spreadsheet with historical analytical data is included as a CD-ROM attachment to this document. Graphical summaries of historical groundwater VOCs content and monitoring and field parameter measurements (i.e., time-series analyses) for all monitoring wells are presented in Appendix A. 4.1 Groundwater Flow Conditions Flow direction and gradient for the first water-bearing unit beneath the landfill is calculated utilizing three point triangulation methods. Groundwater elevation measurements are documented on monitoring well sampling data sheets provided in Appendix B, and are presented in Table 1 and Figure 3. The groundwater flow direction and gradient estimated from the March 2012 sampling event was south 51º west at a gradient of ft/ft. The groundwater flow direction and gradient estimated from the May 2012 sampling event was south 53º west at a gradient of ft/ft. Current and historic groundwater flow directions and gradients are presented in Table 2. A groundwater potentiometric surface maps showing estimated groundwater flow conditions are presented as Figures 4 and 5. Based on MWH s interpretation of well M-1A, as screened across a perched aquifer, the groundwater elevation in for well M-1A was not contoured on the potentiometric surface contour maps for the shallow water-bearing zone. Haling and Associates 4

9 First Semester 2011 Monitoring Report Evans Road Landfill In accordance with the CVRWQCB letter dated 26 June 2008, hydrographs displaying the elevation of groundwater with respect to the elevations of the top and bottom of the screened interval and the elevation of the pump intake for each well are presented in Appendix C. 4.2 Groundwater Monitoring Parameters Groundwater monitoring parameters analyzed during the First Semester 2012 monitoring event included field parameters and monitoring parameters in accordance with the ERL MRP No. R Static groundwater elevation measurements were obtained for all site monitoring wells during the First Semester 2012 monitoring events conducted on 5 March and 23 May Groundwater elevation levels are generally consistent with historical data Groundwater Field Parameters Groundwater temperature, ph, turbidity, and electrical conductivity (EC) recorded for samples collected during the current monitoring period from monitoring wells M-1A, M-1B, M-3A, M-4, and M-5 were generally within the range of historical data previously recorded for each well. Recorded field parameters are documented on monitoring well sampling data sheets provided in Appendix B. Turbidity was measured at the lab, but was analyzed outside the recommended holding time. Current and historical field parameter measurements are presented in Table Groundwater Monitoring Parameters Current and historical measurements of semi-annual groundwater monitoring parameters for the ERL monitoring wells are presented in Table 4. The laboratory analytical report and chain-of-custody documentation are provided in Appendix D. Total dissolved solids (TDS), chloride, sulfate, and nitrate as nitrogen concentrations were generally within the range of historical data for all site monitoring wells. TDS concentrations in wells M-1B (570 mg/l) and M-5 (590 mg/l) exceeded the recommended Environmental Protection Agency (EPA) secondary maximum contaminant level (SMCL) for drinking water of 500 mg/l. All chloride and sulfate concentrations were less than their respective SMCLs (250 mg/l for each) for drinking water. Nitrate as nitrogen concentrations were below the EPA drinking water maximum contaminant level (MCL) of 10 mg/l for all site monitoring wells sampled during the current monitoring event. Sodium, magnesium, and bicarbonate concentrations for samples collected from all site monitoring wells were generally consistent with previously recorded data, though the sodium value recorded at M-1A (38 mg/l) was an historical high for that well. Analyses of groundwater samples for volatile organic compounds (VOCs) were completed for all monitoring wells sampled during the First Semester Current and historically detected Haling and Associates 5

10 First Semester 2011 Monitoring Report Evans Road Landfill VOCs are presented in Table 5. No VOC s were detected during the First Semester VOCs not included in the following discussion of results have not been detected in any landfill monitoring wells for at least eight consecutive monitoring events. Napthalene was not detected above the laboratory PQL of 0.50 µg/l in groundwater samples collected from any site monitoring wells during the First Semester Napthalene was detected during previous monitoring events in samples collected from monitoring well M-1A (March 2010 [5.0 µg/l]), October 2001 [0.79 µg/l]), and in samples collected from monitoring well M-3A (February 2003 [0.21 µg/l]). 1,2,3-Trichlorobenzene was not detected above the laboratory PQL of 0.50 µg/l in groundwater samples collected from any site monitoring wells during the First Semester ,2,3-Trichlorobenzene was detected during a previous monitoring event in samples collected from monitoring well M-3A (March 2010 [1.8 µg/l]). 1,2,4-Trichlorobenzene was not detected above the laboratory PQL of 0.50 µg/l in groundwater samples collected from any site monitoring wells during the First Semester ,2,4-Trichlorobenzene was detected during a previous monitoring event in samples collected from monitoring well M-1A (March 2010 [2.4 µg/l]). Chloromethane was not detected above the laboratory PQL of 0.50 µg/l in groundwater samples collected from any site monitoring wells during the First Semester Chloromethane was detected during a previous monitoring event in samples collected from monitoring wells M-1A (July 2010 [0.80 µg/l], March 2011 [3.80 µg/l]), M-1B (July 2010 [0.76 µg/l], March 2011 [0.91 µg/l]), M-3A (January 2009 [0.65 µg/l]), M-4 (March 2011 [2.70 µg/l]), and M-5 (July 2010 [0.90 µg/l], March 2011 [4.40 µg/l]). 1,1-Dichloroethane (1,1-DCA) was not detected above the laboratory PQL of 0.50 µg/l in groundwater samples collected from any site monitoring wells during the First Semester ,1-DCA was detected during previous monitoring events in samples collected from monitoring well M-1B (February 2003 [0.85 µg/l], August 2003 [0.64 µg/l], October 2003 [0.65 µg/l], March 2004 [0.49 µg/l], August 2004 [1.0 µg/l], March 2005 [0.83 µg/l], July 2005 [1.1 µg/l], May 2006 [0.67 µg/l], March 2007 [0.56 µg/l], August 2007 [0.69 µg/l], August 2008 [0.65 µg/l], January 2009 [0.65 µg/l], July 2009 [0.63 µg/l], and March 2010 [0.55 µg/l]) Di-isopropyl ether (DIPE) was not detected above the laboratory PQL of 0.50 µg/l in the groundwater samples collected during the second semester. DIPE was Haling and Associates 6

11 First Semester 2011 Monitoring Report Evans Road Landfill detected during previous monitoring events in samples collected from site monitoring wells M-1B (July 2005 [0.81 µg/l], May 2006 [0.52 µg/l], March 2007 [0.79 µg/l], August 2007 [0.60 µg/l], and January 2009 [0.35 µg/l]), and M-5 (July 2005 [0.95 µg/l], May 2006 [0.51 µg/l], October 2006 [0.70 µg/l], March 2007 [0.76 µg/l], August 2007 [0.69 µg/l], August 2008 [0.84 µg/l], January 2009 [0.91 µg/l], July 2009 [0.78 µg/l], March 2010 [0.63 µg/l] ], and July 2010 [0.94 µg/l]). Ethanol was not detected above the laboratory PQL of 25 µg/l in groundwater samples collected from any site monitoring wells during the First Semester Ethanol was detected during previous monitoring events in samples collected from site monitoring well M-5 (July 2009 [40 µg/l] and March 2010 [92 µg/l]). Methyl ethyl ketone was not detected above the laboratory PQL of 1.0 µg/l in groundwater samples collected from any site monitoring wells during the First Semester Methyl ethyl ketone was detected during previous monitoring events in samples collected from site monitoring wells M-1A (March 2007 [3,500 µg/l, estimated with high bias]), M-1B (March 2007 [45 µg/l, estimated with high bias]), M-3A (March 2007 [5.3 µg/l, estimated with high bias]), M-4 (March 2007 [8.4 µg/l, estimated with high bias]), and M-5 (March 2007 [6.9 µg/l, estimated with high bias] and March 2010 [1.1 µg/l]). Acetone was not detected above the laboratory PQL of 5.0 µg/l in groundwater samples collected from any site monitoring wells during the First Semester Acetone was detected during previous monitoring events in samples collected from site monitoring wells M-1A (March 2007 [5,200 µg/l, estimated with high bias]), M-1B (March 2007 [9.7 µg/l, estimated with high bias]), M-3A (March 2007 [9.7 µg/l, estimated with high bias], (March 2011 [7.7 µg/l]), M-4 (October 2006 [5.3 µg/l], (March 2011 [3.2 µg/l]), and M-5 (August 2003 [3.3 µg/l], March 2004 [12 µg/l] and March 2007 [7.3 µg/l, estimated with high bias]) Five-Year Constituents of Concern In accordance with MRP R , monitoring parameters analyzed as five-year constituents of concern (COCs) at ERL include total organic carbon, dissolved inorganics, VOCs (EPA Method 8260B, extended list), semi-volatile organic compounds (SVOCs) (EPA Method 8270C), chlorophenoxy herbicides (EPA Method 8151A), and organophosphorous compounds (EPA Method 8141A). Haling and Associates 7

12 First Semester 2011 Monitoring Report Evans Road Landfill Five-year COCs were last measured at monitoring wells M-1B and M-5 during the second semester 2008, at monitoring well M-1A during second semester 2009, and at monitoring wells M- 3A and M-4 during the second semester Historic five-year COCs groundwater monitoring data are provided in Tables 6 and Quality Assurance/Quality Control A field duplicate was collected during the March 2012 sampling event as a quality assurance/quality control measures to monitor laboratory analytical precision. The field duplicate was collected at monitoring well M-1B and labeled as M-6. The field duplicate was measured for VOCs by EPA Method 8260B. No VOCs were detected in the M-1B sample or the duplicate sample M-6 during the March 2012 sampling event. The spike recovery was outside acceptance limits for the MS and/or the MSD due to analyte concentration at 4 times or greater the spike concentration. The LCS and/or LCSD were within acceptance limits showing that the laboratory is in control and the data is acceptable. No other QA/QC flags were noted by the laboratory for analytical results from matrix spikes, matrix spike duplicates, laboratory control samples, and laboratory control duplicate samples during the current semester. 4.3 Surface Water Conditions Surface water was not present on 5 March and 23 May 2012 at sampling locations S-1 and S-2. Surface water samples were last collected during the first semester of Historic semi-annual surface water analytical results are presented in Table 8. Five-year Constituents of Concern (COCs) surface water analytical results for monitoring locations S-1 and S-2 were last analyzed in January 2008 and are summarized in Tables 8 and Landfill Gas Measurements Passive Landfill Gas Vents First Semester 2012 passive landfill gas vent measurements were completed on 5 March and 23 May 2012 for gas vents V-1 through V-7. Methane was detected on 5 March at landfill gas vent V-7 at a concentration of 4.4 percent by volume. The methane measurement at the other gas vents during First Semester 2012 was 0.0 percent by volume. Methane was detected on 23 May at landfill gas vents V-1, V-2, V-4, V-5, V-6 and V-7 at a concentration of 0.1, 0.2, 1.3, 4.2, 11.6, and 2.2 percent by volume respectively. The methane measurement at gas vent V-3 during First Haling and Associates 8

13 First Semester 2011 Monitoring Report Evans Road Landfill Semester 2012 was 0.0 percent by volume. Carbon dioxide and oxygen measurements were also completed during gas vent monitoring. Current and historical landfill gas measurements are provided in Table 10. Soil Gas Monitoring Wells First Semester 2012 soil gas measurements at four sets of nested perimeter soil gas monitoring wells were completed on 5 March and 23 May 2012 for shallow (S) and deep (D) soil gas probes located within the vadose zone at gas wells GW-1 through GW-4. All methane measurements at gas vents during First Semester 2012 were 0.0 percent by volume. Carbon dioxide and oxygen measurements were also completed during gas well monitoring. Current and historical soil gas probe measurements are provided in Table 11 and historic soil gas VOC data is presented in Table CONCENTRATION LIMITS As specified in WDR No. R , concentration limits were established for all COCs following four quarters of monitoring, in accordance with a statistical method pursuant to Title 27 CCR Section Concentration limits for ERL monitored parameters and COCs are established and evaluated using the concentration interval method. Concentration limits are re-calculated following each sampling event, and reflect the upper tolerance interval based on a confidence level of 95 percent for individual parameter data at background well, M-4 (background well). The 95% tolerance coefficient used for this statistical analysis implies that at least 95% of observations from down-gradient wells should fall below the concentration limit. The concentration limits for the monitoring parameters, field parameters, and five-year COCs are then compared with the most recent down-gradient well concentrations. If a parameter concentration detected in a sample from a down-gradient well exceeds the established concentration limit, it is interpreted as statistically significant evidence of contamination. M-1A was historically considered the background well for previous statistical analyses. However, as the last six monitoring events prior to 2010 indicated that groundwater flow direction at ERL is to the southwest, it is apparent that M-1A is hydraulically down-gradient from the landfill, as is M- 1B, while wells M-3A, M-4, and M-5 are up-gradient of the landfill. Therefore, statistical analysis to evaluate groundwater monitoring data was modified to use values from well M-4 to establish the concentration limits, as historically monitoring well M-4 has had the least VOC detections indicating the well has had limited impacts. Haling and Associates 9

14 First Semester 2011 Monitoring Report Evans Road Landfill A non-statistical method is used to analyze the VOC data. Exceedence of a PQL for a single constituent at a monitoring well is considered significant. 5.1 Methods The TL for groundwater monitoring parameters measured is calculated as follows based on the entire available data set for monitoring well M-4: TL = + KS Where: TL the upper tolerance limit the mean value for a groundwater parameter at a single monitoring well K the one-sided normal tolerance factor S the standard deviation for a groundwater parameter at a single monitoring well Data for each tested parameter were transformed lognormally prior to calculation of TLs to produce a normal distribution required by the statistical method. The one-sided normal tolerance factor was calculated with the aid of a Student s t-distribution table as follows: K = t n-1, * sqrt(1+1/n), where n is the number of observations The regular use of J flags in results reporting is now well established. Therefore, in accordance with RCRA Waste Sampling Draft Technical Guidance (EPA, 2002) the use of Cohen s Adjustment (utilized in previous reports) is no longer necessary for nitrate as nitrogen data from M-4. For this report, the nitrate TL was calculated in the same manner as described above. Comparison of calculated TLs from up-gradient well, M-4, and constituent concentrations measured in samples collected at down-gradient wells during the First Semester 2012 monitoring event are provided in Table Results At monitoring well M-1A, measurements of TDS, chloride, sulfate, nitrate as nitrogen, and Electrical Conductivity (EC) did not exceed the respective concentration limits. The concentration limit was exceeded for ph and turbidity. At monitoring well M-1B, measurements of TDS, chloride, sulfate, nitrate as nitrogen, ph, EC, and turbidity did not exceed the respective concentration limits. At monitoring well M-3A, measurements of TDS, chloride, nitrate as nitrogen, ph, and EC did not exceed the respective concentration limits. The concentration limit was exceeded for sulfate and turbidity. Haling and Associates 10

15 First Semester 2011 Monitoring Report Evans Road Landfill At monitoring well M-4, measurements of TDS, chloride, sulfate, nitrate as nitrogen, ph, and EC did not exceed the respective concentration limits. The concentration limit was exceeded for turbidity. At monitoring well M-5, measurements of TDS, sulfate, nitrate as nitrogen, ph, and EC did not exceed the respective concentration limits. The concentration limit was exceeded for chloride and turbidity. 6.0 SUMMARY The following summarizes results of the First Semester 2012 monitoring events: Groundwater flow direction and gradient were generally consistent with historical observations. Groundwater flow was estimated to the southwest (S 51º W at ft/ft [March 2012] and S 53º W at ft/ft [May 2012]). Field and monitoring parameter measurements for groundwater samples collected on 5 March 2012 from monitoring wells M-1A, M-1B, M-3A, M-4 and M-5 were generally consistent with previous measurements. TDS concentrations in monitoring well M-1B (570 mg/l) and M-5 (590 mg/l) exceeded the recommended SMCL for drinking water of 500 mg/l. All chloride and sulfate concentrations were below their respective SMCLs (250 mg/l for each) for drinking water. All nitrate as nitrogen concentrations were below the drinking water MCL of 10 mg/l. Sodium was recorded at an historical high for well M-1A (38 mg/l). No VOCs were detected at ERL during the First Semester Surface water was not present on 5 March and 23 May 2012 at sampling locations S-1 and S-2 following rainfall events. Methane measurements from six of the passive landfill gas vents did not exceed 0.0 percent by volume during the 5 March 2012 sampling event. The exception was that methane was detected on 5 March at landfill gas vent V-7 at a concentration of 4.4 percent by volume. Methane was detected on 23 May at landfill gas vents V-1, V-2, V-4, V-5, V-6 and V-7 at a concentration of 0.1, 0.2, 1.3, 4.2, 11.6, and 2.2 percent by volume respectively. Methane was not detected above the CalRecycle (formerly CIWMB) limit of 5 percent methane by volume at the four perimeter soil gas monitoring wells GW-1, GW-2, GW-3, and GW-4 (in the shallow and deep probes) during the First Semester Haling and Associates 11

16 FIGURES

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19 Figure 3. Groundwater Elevation Measurements Evans Road Landfill, Colusa County M-1 M-1A M-1B M-2 M-3 M-3A M-4 M-5 Z:\H&A\1081 Colusa Landfills\Evans Road\2012\1S2012\Report\Evans 1S2012 Tables.xls Groundwater Elevation (ft. amsl) Jan-95 Jul-95 Jan-96 Jul-96 Jan-97 Jul-97 Jan-98 Jul-98 Jan-99 Jul-99 Jan-00 Jul-00 Jan-01 Jul-01 Jan-02 Jul-02 Jan-03 Jul-03 Jan-04 Jul-04 Jan-05 Jul-05 Jan-06 Jul-06 Jan-07 Jul-07 Jan-08 Jul-08 Jan-09 Jul-09 Jan-10 Jul-10 Jan-11 Jul-11 Jan-12

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22 TABLES

23 Table 1. HISTORICAL GROUNDWATER ELEVATION DATA March May 2012 Evans Road Landfill Monitoring Report TOC Elevation (ft above MSL) M-1 M-1A M-1B M-2 M-3 M-3A M-4 M Groundwater Elevation (ft above MSL) Date Measured M-1 M-1A M-1B M-2 M-3 M-3A M-4 M-5 27-Mar Jun Dry Sep-95 Dry NA Dec-95 NA NA NA May-96 NA NA NA Jul NA Mar NA May NA Sep NA Nov NA Apr NA Jul Wells Abandoned Sep Dec Apr May Oct Apr Feb-01 Dry Jun-01 Dry Oct-01 Dry May-02 Dry Feb-03 Well Abandoned May Aug Oct Mar May Aug Nov Mar Jun Jul Dec Mar May Aug Oct Mar May Aug Oct Mar May Aug Oct Jan Apr Jul Oct Z:\H&A\1081 Colusa Landfills\Evans Road\2012\1S2012\Report\Evans 1S2012 Tables.xls

24 Table 1 (Concluded) Groundwater Elevation (ft above MSL) Date Measured M-1 M-1A M-1B M-2 M-3 M-3A M-4 M-5 24-Mar May Jul Dry Oct Dry Mar Jun Aug Oct Mar May Z:\H&A\1081 Colusa Landfills\Evans Road\2012\1S2012\Report\Evans 1S2012 Tables.xls

25 Table 2. GROUNDWATER FLOW DIRECTION AND GRADIENT March May 2012 Colusa County Landfill -- Evans Road, Monitoring Summary Repo Date Measured Average Flow Direction Average Gradient (ft/ft) 30-Mar-05 S 47 W Jun-05 S 44 W Jul-05 S 41 W Dec-07 S 53 W Mar-06 N 83 W May-06 S 89 W Aug-06 S 51 W Oct-06 S 54 W Mar-07 S 61 W May-07 S 63 W Aug-07 S 64 W Oct-07 S 61 W Mar-08 S 62 W May-08 S 63 W Aug-08 S 55 W Oct-08 S 65 W Jan-09 S 67 W Apr-09 S 58 W Jul-09 S 68 W Oct-09 S 67 W Mar-10 S 52 W May-10 S 57 W Jul-10 S 41 W Oct-10 S 53 W Mar-11 S 45 W Jun-11 S 44 W Aug-11 S 52 W Oct-11 S 50 W Mar-12 S 51 W May-12 S 53 W NC - Not calculated Z:\H&A\1081 Colusa Landfills\Evans Road\2012\1S2012\Report\Evans 1S2012 Tables.xls

26 Table 3. GROUNDWATER FIELD PARAMETERS March May 2012 Evans Road Landfill Monitoring Report ph Temperature ( o C) Sample Sample Date M-1A M-1B M-3A M-4 M-5 Date M-1A M-1B M-3A M-4 M-5 Mar-97 7 Mar-97 Sep Sep-97 Apr Apr-98 Jul NA Jul-98 Jan Jan-99 May May-99 Oct Oct-99 Apr-00 NA NA NA Apr-00 May NA May-00 Feb NA Feb-01 Jun NA Jun-01 Oct Oct-01 May May-02 Feb Feb-03 May May-03 Aug Aug-03 Oct-03 NA 7.14 NA NA NA Oct-03 Mar Mar-04 Aug Aug-04 Mar Mar Jul Jul May May Oct Oct Mar Mar Aug Aug Mar Mar Aug Aug Jan Jan Jul NA 7.57 Jul NA 21.5 Mar Mar Jul NA 6.46 Jul NA 22.0 Mar Mar Aug NA 6.84 Aug NA 22.3 Mar Mar Z:\H&A\1081 Colusa Landfills\Evans Road\2012\1S2012\Report\Evans 1S2012 Tables.xls

27 Table 3 (concluded) Electrical Conductivity (mhos/cm) Turbidity (NTUs) Sample Sample Date M-1A M-1B M-3A M-4 M-5 Date M-1A M-1B M-3A M-4 M-5 Mar Mar-97 NA Sep Sep-97 NA Apr Apr-98 NA Jul NA Jul-98 NA NA NA Jan Jan , May May-99 NA NA NA Oct Oct-99 1, Apr-00 NA NA NA Apr-00 NA NA NA May NA May-00 NA NA NA Feb NA Feb-01 NA NA NA Jun NA Jun-01 NA NA NA Oct Oct-01 NA NA NA May May-02 NA NA NA Feb-03 1,091 1, Feb May , May-03 NA NA NA NA NA Aug , Aug-03 NA > Oct-03 NA 1,379 NA NA NA Oct-03 NA 26 NA NA NA Mar , Mar Aug ,146 1,061 1,088 1,011 Aug Mar , ,380 Mar Jul , ,350 Jul May , ,280 May Oct , ,480 Oct Mar , ,356 Mar Aug , ,308 Aug-07 5, Jun , ,214 Aug Aug , ,208 Aug-08 1, Jan ,075 1, ,219 Jan Jul NA 1,229 Jul-09 1,700 1, NA 1,600 Mar Mar Jul ,039 1,088 NA 1,314 Jul-10 1, NA 650 Mar , ,039 Mar Aug NA 986 Aug ,400 1,500 NA 2,400 Mar Mar ,200 NA - Not analyzed (well possibly dry) (1) - ph analyzed by laboratory Z:\H&A\1081 Colusa Landfills\Evans Road\2012\1S2012\Report\Evans 1S2012 Tables.xls

28 Table 4. SEMI-ANNUAL GROUNDWATER MONITORING PARAMETERS March May 2012 Evans Road Landfill Monitoring Report Total Dissolved Solids (mg/l) Chloride (mg/l) SMCL: 500 mg/l (recommended) SMCL: 250 mg/l (recommended) Sample Sample Date M-1A M-1B M-3A M-4 M-5 Date M-1A M-1B M-3A M-4 M-5 Mar Mar Sep Sep Apr Apr Jul NA Jul NA Jan Jan May May Oct Oct Apr-00 NA NA NA Apr-00 NA NA NA May May NA Feb NA Feb NA Jun NA Jun NA Oct Oct May May Feb Feb May-03 NA NA NA NA NA May-03 NA NA NA NA NA Aug Aug Oct-03 NA NA NA NA NA Oct-03 NA NA NA NA NA Mar Mar Aug Aug Mar Mar Jul , Jul May May Oct Oct Mar Mar Aug Aug Mar Mar Aug Aug Jan Jan Jul NA 660 Jul NA 38 Mar Mar Jul NA 640 Jul NA 38 Mar Mar Aug NA 610 Aug NA 42 Mar Mar Z:\H&A\1081 Colusa Landfills\Evans Road\2012\1S2012\Report\Evans 1S2012 Tables.xls

29 Table 4 (continued) Sample Sulfate as SO 4 (mg/l) SMCL: 250 mg/l (recommended) Date M-1A M-1B M-3A M-4 M-5 Date M-1A M-1B M-3A M-4 M-5 Mar Mar Sep Sep Apr Apr-98 <1 Jul NA Jul NA Jan Jan <0.226 May May <0.226 Oct Oct <0.226 Apr-00 NA NA NA Apr-00 NA NA NA May NA May NA Feb NA Feb NA Jun NA Jun NA Oct Oct May May Feb Feb <0.014 May-03 NA NA NA NA NA May-03 NA NA NA NA NA Aug NA NA NA NA Aug-03 NA <0.011 Oct-03 NA NA NA NA NA Oct-03 NA NA NA NA NA Mar Mar <0.016 Aug Aug <0.018 Mar Mar <0.20 Jul Jul < <0.20 May May < <0.20 Oct Oct < <0.20 Mar Mar < <0.20 Aug Aug Mar Mar < <0.20 Aug Aug Jan Jan (J) (J) 0.12 (J) Jul NA 22 Jul (J) 1.0 NA 0.12 (J) Mar Mar (J) Jul NA 24 Jul (J) 0.98 NA 0.13 (J) Mar Mar (J) (J) Aug NA 28 Aug (J) 1.40 NA 0.26 Mar Mar (J) (J) Sample Nitrate as N (mg/l) MCL: 10 mg/l Z:\H&A\1081 Colusa Landfills\Evans Road\2012\1S2012\Report\Evans 1S2012 Tables.xls

30 Table 4 (continued) Sodium (mg/l) Magnesium (mg/l) Sample Sample Date M-1A M-1B M-3A M-4 M-5 Date M-1A M-1B M-3A M-4 M-5 Feb Feb May-03 NA NA NA NA NA May-03 NA NA NA NA NA Aug Aug Oct-03 NA NA NA NA NA Oct-03 NA NA NA NA NA Mar Mar Aug Aug Mar Mar Jul Jul May May Oct Oct Mar Mar Aug Aug Mar Mar Aug Aug Jan Jan Jul NA 26 Jul NA 85 Mar Mar Jul NA 28 Jul NA 96 Mar Mar Aug NA 22 Aug NA 120 Mar Mar Z:\H&A\1081 Colusa Landfills\Evans Road\2012\1S2012\Report\Evans 1S2012 Tables.xls

31 Table 4 (concluded) Sample Bicarbonate (mg/l) Date M-1A M-1B M-3A M-4 M-5 Feb May-03 NA NA NA NA NA Aug Oct-03 NA NA NA NA NA Mar Aug Mar Jul May Oct Mar Aug Mar Aug Jan Jul NA 680 Mar Jul NA 740 Mar Aug NA 640 NA - Not analyzed (well possibly dry) J - Detected but below the Reporting Limit; therefore, result is an estimated concentration, detected but not quantified (DNQ). SMCL - Secondary Maximum Contaminant Level fro drinking water, State of California MCL - Maximum Contaminant Level fro drinking water, State of California Z:\H&A\1081 Colusa Landfills\Evans Road\2012\1S2012\Report\Evans 1S2012 Tables.xls

32 Table 5. DETECTED VOLATILE ORGANIC COMPOUNDS - GROUNDWATER March May 2012 Evans Road Landfill Monitoring Report Practical Quantitation Limit (O.C.) Method Detection Limit Sample Location ID Date Sampled Analyte Results Lab Qualifiers Units M-1A 03/07/07 Acetone 5,200 J+ µg/l 02/24/03 Benzene 0.19 µg/l 07/14/10 Chloromethane µg/l 03/29/11 Chloromethane µg/l 02/24/03 Dichlorodifluoromethane µg/l 08/12/03 Dichlorodifluoromethane 0.14 µg/l 03/07/07 Methyl ethyl ketone 3,500 J+ µg/l 05/19/03 Methylene chloride 3.7 µg/l 10/22/01 Naphthalene 0.79 µg/l 03/24/10 Naphthalene µg/l 02/24/03 Toluene 0.24 µg/l 03/24/10 1,2,4-Trichlorobenzene µg/l 02/24/03 Total xylenes 0.40 µg/l M-1B 03/07/07 Acetone 9.7 J+ µg/l 02/24/03 Benzene 0.12 µg/l 03/31/04 Benzene 0.10 µg/l 07/14/10 Chloromethane µg/l 03/29/11 Chloromethane µg/l 02/24/03 Dichlorodifluoromethane 0.80 µg/l 08/12/03 Dichlorodifluoromethane 0.55 µg/l 10/01/03 Dichlorodifluoromethane 0.45 µg/l 03/31/04 Dichlorodifluoromethane 0.58 µg/l 08/19/04 Dichlorodifluoromethane 0.68 µg/l 07/28/05 Dichlorodifluoromethane 0.67 µg/l 02/24/03 1,1-Dichloroethane 0.85 µg/l 08/12/03 1,1-Dichloroethane 0.64 µg/l 10/01/03 1,1-Dichloroethane 0.65 µg/l 03/31/04 1,1-Dichloroethane 0.49 µg/l 08/19/04 1,1-Dichloroethane 1.0 µg/l 03/30/05 1,1-Dichloroethane 0.83 µg/l 07/28/05 1,1-Dichloroethane 1.1 µg/l 05/06/06 1,1-Dichloroethane 0.67 µg/l 03/07/07 1,1-Dichloroethane 0.56 µg/l 08/07/07 1,1-Dichloroethane 0.69 µg/l 08/20/08 1,1-Dichloroethane µg/l 01/21/09 1,1-Dichloroethane µg/l 07/23/09 1,1-Dichloroethane µg/l 03/24/10 1,1-Dichloroethane µg/l 02/24/03 Cis-1,2-Dichloroethene 0.18 µg/l 08/12/03 Cis-1,2-Dichloroethene 0.14 µg/l 03/31/04 Cis-1,2-Dichloroethene 0.85 µg/l 08/19/04 Cis-1,2-Dichloroethene 1.1 µg/l 03/30/05 Cis-1,2-Dichloroethene 0.69 µg/l 07/28/05 Cis-1,2-Dichloroethene 0.90 µg/l 05/06/06 Cis-1,2-Dichloroethene 0.62 µg/l 03/07/07 Cis-1,2-Dichloroethene 0.82 µg/l 08/07/07 Cis-1,2-Dichloroethene 0.62 µg/l 07/28/05 Di-isopropyl ether 0.81 µg/l 05/06/06 Di-isopropyl ether 0.52 µg/l Z:\H&A\1081 Colusa Landfills\Evans Road\2012\1S2012\Report\Evans 1S2012 Tables.xls

33 Table 5 (continued) Practical Quantitation Limit Method Detection Limit Sample Location ID Date Sampled Analyte Results Lab Qualifiers Units (M-1B-Cont.) 03/07/07 Di-isopropyl ether 0.79 µg/l 08/07/07 Di-isopropyl ether 0.60 µg/l 01/21/09 Di-isopropyl ether J µg/l 03/07/07 Methyl ethyl ketone 45 J+ µg/l 03/07/07 Methyl tert-butyl ether 1.1 µg/l 05/19/03 Methylene chloride 2.5 µg/l 03/31/04 Methylene chloride 0.31 µg/l 02/24/03 Tetrachloroethene 0.68 µg/l 08/12/03 Tetrachloroethene 0.63 µg/l 10/01/03 Tetrachloroethene 0.57 µg/l 03/31/04 Tetrachloroethene 0.81 µg/l 08/19/04 Tetrachloroethene 0.74 µg/l 07/28/05 Tetrachloroethene 0.58 µg/l 02/24/03 Toluene 0.29 µg/l 02/24/03 Total xylenes 0.25 µg/l 02/24/03 Trichloroethene 0.49 µg/l 08/12/03 Trichloroethene 0.39 µg/l 10/01/03 Trichloroethene 0.42 µg/l 03/31/04 Trichloroethene 0.42 µg/l 08/19/04 Trichloroethene 0.68 µg/l 07/28/05 Trichloroethene 0.58 µg/l M-3A 03/07/07 Acetone 9.7 J+ µg/l 03/29/11 Acetone µg/l 02/24/03 Benzene 6.0 µg/l 01/21/09 Chloromethane µg/l 02/24/03 Ethylbenzene 0.66 µg/l 03/07/07 Methyl ethyl ketone 5.3 J+ µg/l 02/24/03 Methyl tert-butyl ether 0.19 µg/l 02/24/03 Naphthalene 0.21 µg/l 02/24/03 Tetrachloroethene 0.34 µg/l 10/22/01 Toluene 0.55 µg/l 02/24/03 Toluene 3.5 µg/l 03/24/10 1,2,3-Trichlorobenzene µg/l 02/24/03 Total xylenes 5.6 µg/l M-4 10/01/06 Acetone 5.3 µg/l 03/29/11 Acetone J µg/l 02/24/03 Benzene 0.41 µg/l 03/29/11 Chloromethane µg/l 02/24/03 Ethylbenzene 0.12 µg/l 03/07/07 Methyl ethyl ketone 8.4 J+ µg/l 02/24/03 Toluene 0.41 µg/l 02/24/03 Total xylenes 0.86 µg/l Z:\H&A\1081 Colusa Landfills\Evans Road\2012\1S2012\Report\Evans 1S2012 Tables.xls

34 Table 5 (concluded) Practical Quantitation Limit Method Detection Limit Sample Location ID Date Sampled Analyte Results Lab Qualifiers Units M-5 08/12/03 Acetone 3.3 µg/l 03/31/04 Acetone 12 µg/l 03/07/07 Acetone 7.3 J+ µg/l 07/14/10 Chloromethane µg/l 03/29/11 Chloromethane µg/l 02/24/03 Dichlorodifluoromethane 0.21 µg/l 08/12/03 Dichlorodifluoromethane 0.19 µg/l 07/28/05 Di-isopropyl ether 0.95 µg/l 05/06/06 Di-isopropyl ether 0.51 µg/l 10/01/06 Di-isopropyl ether 0.70 µg/l 03/07/07 Di-isopropyl ether 0.76 µg/l 08/07/07 Di-isopropyl ether 0.69 J µg/l 08/20/08 Di-isopropyl ether µg/l 01/21/09 Di-isopropyl ether µg/l 07/23/09 Di-isopropyl ether µg/l 03/24/10 Di-isopropyl ether µg/l 07/14/10 Di-isopropyl ether µg/l 07/23/09 Ethanol µg/l 03/24/10 Ethanol µg/l 02/24/03 Ethylbenzene 0.10 µg/l 03/07/07 Methyl ethyl ketone 6.9 J+ µg/l 03/24/10 Methyl ethyl ketone µg/l 05/19/03 Methylene chloride 3.6 µg/l 02/24/03 Toluene 0.32 µg/l 02/24/03 Total xylenes 0.45 µg/l O.C.-Observed Concentrations in Down-gradient and Cross-gradient Wells g/l - micrograms per liter (parts per billion) NA - not analyzed J - Compound positively identified, results approximate J+ = Results estimated with high bias. Highlighted values are for the most recent monitoring period Z:\H&A\1081 Colusa Landfills\Evans Road\2012\1S2012\Report\Evans 1S2012 Tables.xls

35 Table 6. FIVE-YEAR CONSTITUENTS OF CONCERN -- GROUNDWATER March 1997 to March 2010 Evans Road Landfill Total Organic Carbon (mg/l) Total Suspended Solids (mg/l) Sample Sample Date M-1A M-1B M-3A M-4 M-5 Date M-1A M-1B M-3A M-4 M-5 Mar-97 NA Mar-97 NA Jan-99 NA NA NA Jan , Oct-99 NA NA NA 2.4 Oct-99 1, Feb-03 NA 32 NA NA 13 Feb-03 NR NR NR NR NR Aug NA NA NA NA Mar-10 NR NR NR NR NR Mar-05 NA NA < NA Mar-08 NA 1.50 NA NA 1.77 Jul (J) NA NA NA NA Mar-10 NA NA NA Semi-volatile Organic Compounds (g/l) Organophosphorous Compounds (g/l) Sample Sample Date M-1A M-1B M-3A M-4 M-5 Date M-1A M-1B M-3A M-4 M-5 Mar-97 NA Mar-97 NA Jan-99 NA NA NA Jan-99 NA NA NA Oct-99 NA NA NA Oct-99 NA NA NA Feb-03 NA ND NA NA ND Feb-03 NA ND NA NA ND Aug-04 bis-(2-ethylhexyl) phthalate (2.8 g/l) NA NA NA NA Aug-04 ND NA NA NA NA Mar-05 NA NA ND ND NA Mar-05 NA NA ND ND NA Mar-08 NA ND NA NA ND Mar-08 NA ND NA NA ND Jul-09 ND NA NA NA NA Jul-09 ND NA NA NA NA Mar-10 NA NA bis-(2-ethylhexyl) phthalate (0.167 g/l)(j) bis-(2-ethylhexyl) phthalate (0.452 g/l)(j) NA Mar-10 NA NA ND ND NA Chlorophenoxy Herbicides (g/l) 6/3/11 S 44 W Date M-1A M-1B M-3A M-4 M-5 Mar-97 NA Jan-99 NA NA NA Oct-99 NA NA NA Feb-03 NA ND NA NA ND Aug-04 ND NA NA NA NA Mar-05 NA NA ND ND NA Mar-08 NA ND NA NA ND Jul-09 ND NA NA NA NA Mar-10 NA NA ND ND NA NA - Not analyzed ND - Not detected NR - Not required J - Indicates reported value as an estimated concentration above the MDL and below the method reporting limit. Z:\H&A\1081 Colusa Landfills\Evans Road\2012\1S2012\Report\Evans 1S2012 Tables.xls

36 Table 7. 5-YEAR DISSOLVED INORGANICS -- GROUNDWATER February 2003 to March 2010 Evans Road Landfill Monitoring Report Well Number Date Sampled Al Sb Observed Concentrati ons in Ba Be Cd Cr Co Cu Fe Pb M-1A Aug-04 <12 < <0.17 < <2.7 <0.76 < Jul (J) < (J) < < (J) < (J) 0.018(J) (J) M-1B Feb-03 <0.024 < < Mar <0.020 < < <0.010 <0.010 <0.010 < < M-3A Mar-05 <0.050 <0.020 < < <0.010 <0.010 <0.010 <0.020 <0.10 < Mar (J) < (J) 0.23 < < (J) (J) < (J) < M-4 Mar-05 <0.050 <0.020 < < <0.010 <0.010 <0.010 <0.020 <0.10 < Mar-10 <0.050 <0.020 < < <0.010 <0.010 <0.010 < (J) < M-5 Feb < < < Mar < < <0.010 <0.010 <0.010 <0.020 <0.10 < Well Number i Mn Hg Ni Se Ag Tl Sn V Zn Cyanide Sulfide M-1A Aug-04 <0.44 <0.050 <0.25 <0.34 < < < <0.50 Jul-09 <0.020 < < (J) <0.010 <0.20 < (J) (J) < M-1B Feb < < < < < <1.3 Mar < <0.010 < <0.010 <0.20 <0.050 <0.020 <0.020 <0.020 <0.010 M-3A Mar-05 <0.020 < <0.010 < <0.010 <0.20 <0.050 <0.020 <0.020 < /3/11 S 44 W < <0.010 < < (J) <0.050 < (J) < M-4 Mar < <0.010 < <0.010 <0.20 <0.050 <0.020 <0.020 <0.020 Mar (J) < <0.010 < <0.010 <0.20 <0.050 < (J) < M-5 Feb < < < < < <0.50 Mar < <0.010 < <0.010 <0.20 <0.050 <0.020 <0.020 <0.020 <0.010 Concentrations are in milligrams per liter (parts per million) < - no contaminant concentrations detected above the method reporting limt Bold values indicate analyte detections above the method detection limit J - Detected but below the Reporting Limit; therefore, result is an estimated concentration, detected but not quantified (DNQ). NA - Not Analyzed Z:\H&A\1081 Colusa Landfills\Evans Road\2012\1S2012\Report\Evans 1S2012 Tables.xls

37 Table 8. WATER QUALITY PARAMETERS - SURFACE WATER February May 2012 Evans Road Landfill Monitoring Report Total Down-grad Total Dissolved Nitrate as Oil and Organic VOCs Sample Date Bicarbonate Solids Chloride Sulfate Nitrogen Grease Carbon Magnesium Sodium (EPA 8260B) ID Sampled (mg/l) (mg/l) (mg/l) (mg/l) (mg/l) (mg/l) (mg/l) (mg/l) (mg/l) (g/l) S-1 Feb < ND Jan <5.0 NA NA NA ND Feb NA acetone (6.0 µg/l) Jan (J) 2.6 (J) NA ND Jan <5.0 NA ND Mar (J) NA acetone (4.3 µg/l) S-2 Feb < ND Jan <5.0 NA NA NA acetone (6.2 µg/l) Feb NA acetone (4.2 µg/l) Jan (J) NA ND Jan <5.0 NA ND Mar NA acetone (2.7 µg/l) Organo- Total Chlorophenoxy phosphorous Specific Suspended Herbicides Compounds SVOCs Approx. Sample Date ph Temperature Conductance Turbidity Solids (EPA 8151) (EPA 8141) (EPA 8270) Flow Total Iron ID Sampled (ph units) ( o C) (mhos/cm) (NTU) (mg/l) (g/l) (g/l) (g/l) Cubic ft/sec (mg/l) S-1 Feb-05 NA NA NA 50 NA NR NR NR NA NA Jan NA ND ND ND NA NA Feb NA NR NR NR NA NA Jan NR NR NR 0.75 NA Jan NR NR NR 0.40 NA Mar NR NR NR S-2 Feb-05 NA NA NA 45 NA NR NR NR NA NA Jan NA ND ND ND NA NA Feb NA NR NR NR NA NA Jan NR NR NR 1.5 NA Jan NR NR NR 0.30 NA Mar NR NR NR J - Detected but below the Reporting Limit; therefore, result is an estimated concentration, detected but not quantified (DNQ). ND - not detected NA - not analyzed NR - not required Z:\H&A\1081 Colusa Landfills\Evans Road\2012\1S2012\Report\Evans 1S2012 Tables.xls

38 Table 9. 5-YEAR DISSOLVED INORGANICS - SURFACE WATER January 2008 Evans Road Landfill Monitoring Report Sample ID Date Sampled Al Sb Observed Concentrat ions in Ba Be Cd Cr Co Cu Fe Pb S-1 23-Jan <0.020 < <0.010 <0.010 <0.050 <0.020 < < S-2 23-Jan <0.020 < <0.010 <0.050 <0.020 < < Sample ID Date Sampled Mn Hg Ni Se Ag Tl Sn V Zn Cyanide Sulfide S-1 23-Jan-08 <0.050 < <0.10 < <0.050 <0.40 <0.50 <0.50 <0.10 <0.020 <0.10 S-2 23-Jan-08 <0.050 < <0.10 < <0.050 <0.40 <0.50 <0.50 <0.10 <0.020 <0.10 Concentrations are in milligrams per liter (parts per million) < - no contaminant concentrations detected above the method reporting limt Bold values indicate analyte detections Z:\H&A\1081 Colusa Landfills\Evans Road\2012\1S2012\Report\Evans 1S2012 Tables.xls

39 Table 10. Gas Vent Results March May 2012 Evans Road Landfill Monitoring Report Carbon Well Sample Methane (CH 4 ) Dioxide (CO 2 ) Number Date (% volume) (% volume) (% volume) V-1 14-Mar May Aug Oct Mar May Aug Oct Jan Apr Jul Oct Mar May Jul Oct Mar May Aug Oct Mar May V-2 14-Mar May Aug Oct Mar May Aug Oct Jan Apr Jul Oct Mar May Jul Oct Mar May Aug Oct Mar May Z:\H&A\1081 Colusa Landfills\Evans Road\2012\1S2012\Report\Evans 1S2012 Tables.xls

40 Table 10 (continued) Carbon Well Sample Methane (CH 4 ) Dioxide (CO 2 ) Oxygen (O 2 ) Number Date (% volume) (% volume) (% volume) V-3 14-Mar May Aug Oct Mar May Aug Oct Jan Apr Jul Oct Mar May Jul Oct Mar May Aug Oct Mar May V-4 14-Mar May Aug Oct Mar May Aug Oct Jan Apr Jul Oct Mar May Jul Oct Mar May Aug Oct Mar May Z:\H&A\1081 Colusa Landfills\Evans Road\2012\1S2012\Report\Evans 1S2012 Tables.xls

41 Table 10 (continued) Carbon Well Sample Methane (CH 4 ) Dioxide (CO 2 ) Oxygen (O 2 ) Number Date (% volume) (% volume) (% volume) V-5 14-Mar May Aug Oct Mar May Aug Oct Jan Apr Jul Oct Mar May Jul Oct Mar May Aug Oct Mar May V-6 14-Mar May Aug Oct Mar May Aug Oct Jan Apr Jul Oct Mar May Jul Oct Mar May Aug Oct Mar May Z:\H&A\1081 Colusa Landfills\Evans Road\2012\1S2012\Report\Evans 1S2012 Tables.xls

42 Table 10 (concluded) Carbon Well Sample Methane (CH 4 ) Dioxide (CO 2 ) Oxygen (O 2 ) Number Date (% volume) (% volume) (% volume) V-7 14-Mar May Aug Oct Mar May Aug Oct Jan Apr Jul Oct Mar May Jul Oct Mar May Aug Oct Mar May Z:\H&A\1081 Colusa Landfills\Evans Road\2012\1S2012\Report\Evans 1S2012 Tables.xls

43 Table 11. SOIL GAS MONITORING POINTS August May 2012 Evans Road Landfill Monitoring Report Carbon Barometric Sampling Date Methane (CH 4 ) Dioxide (CO 2 ) Pressure Point Sampled (% volume) (% volume) (% volume) (inches Hg) GW-1S Aug NM Nov NM Mar NM Jun NM Jul NM Dec Mar May Aug Oct Mar May Aug Oct Mar May Aug Oct Jan Apr Jul Oct Mar May Jul Oct Mar May Aug Oct Mar May GW-1D Aug NM Nov NM Mar NM Jun NM Jul NM Dec Mar May Aug Oct Mar May Aug Oct Z:\H&A\1081 Colusa Landfills\Evans Road\2012\1S2012\Report\Evans 1S2012 Tables.xls

44 Table 11 (continued) Carbon Barometric Sampling Date Methane (CH 4 ) Dioxide (CO 2 ) Oxygen (O 2 ) Pressure Point Sampled (% volume) (% volume) (% volume) (inches Hg) (GW-1D-Cont.) Mar May Aug Oct Jan Apr Jul Oct Mar May Jul Oct Mar Aug Oct Mar May GW-2S Aug NM Nov NM Mar NM Jun NM Jul NM Dec Mar May Aug Oct Mar May Aug Oct Mar May Aug Oct Jan Apr Jul Oct Mar May Jul Oct Mar May Aug Oct Mar May Z:\H&A\1081 Colusa Landfills\Evans Road\2012\1S2012\Report\Evans 1S2012 Tables.xls

45 Table 11 (continued) Carbon Barometric Sampling Date Methane (CH 4 ) Dioxide (CO 2 ) Oxygen (O 2 ) Pressure Point Sampled (% volume) (% volume) (% volume) (inches Hg) GW-2D Aug NM Nov NM Mar NM Jun NM Jul NM Dec Mar May Aug Oct Mar May Aug Oct Mar May Aug Oct Jan Apr Jul Oct Mar May Jul Oct Mar May Aug Oct Mar May GW-3S Aug NM Nov NM Mar NM Jun NM Jul NM Dec Mar May Aug Oct Mar May Aug Oct Mar May Aug Z:\H&A\1081 Colusa Landfills\Evans Road\2012\1S2012\Report\Evans 1S2012 Tables.xls

46 Table 11 (continued) Carbon Barometric Sampling Date Methane (CH 4 ) Dioxide (CO 2 ) Oxygen (O 2 ) Pressure Point Sampled (% volume) (% volume) (% volume) (inches Hg) (GW-3S-Cont.) Oct Jan Apr Jul Oct Mar May Jul Oct Mar May Aug Oct Mar May GW-3D Aug NM Nov NM Mar NM Jun NM Jul NM Dec Mar May Aug Oct Mar May Aug Oct Mar May Aug Oct Jan Apr Jul Oct Mar May Jul Oct Mar May Aug Oct Mar May GW-4S Aug NM Z:\H&A\1081 Colusa Landfills\Evans Road\2012\1S2012\Report\Evans 1S2012 Tables.xls

47 Table 11 (concluded) Carbon Barometric Sampling Date Methane (CH 4 ) Dioxide (CO 2 ) Oxygen (O 2 ) Pressure Point Sampled (% volume) (% volume) (% volume) (inches Hg) (GW-4S-Cont.) Nov NM Mar NM Jun NM Jul NM Dec Mar May Aug Oct Mar May Aug Oct Jan Apr Jul Oct Mar May Jul Oct Mar May Aug Oct Mar May GW-4D Aug NM Nov NM Mar NM Jun NM Jul NM Dec Mar May Aug Oct Mar May Aug Oct Mar May Aug Oct Jan Apr Jul Oct Z:\H&A\1081 Colusa Landfills\Evans Road\2012\1S2012\Report\Evans 1S2012 Tables.xls

48 Table 11 (concluded) Carbon Barometric Sampling Date Methane (CH 4 ) Dioxide (CO 2 ) Oxygen (O 2 ) Pressure Point Sampled (% volume) (% volume) (% volume) (inches Hg) (GW-4D-Cont.) Mar May Jul Oct Mar May Aug Oct Mar May CalRecycle (formerly CIWMB) limit 5%. NM - Not measured Z:\H&A\1081 Colusa Landfills\Evans Road\2012\1S2012\Report\Evans 1S2012 Tables.xls

49 Table 12. VOLATILE ORGANIC COMPOUNDS -- SOIL GAS August 2004 Evans Road Landfill Monitoring Report Sample Designation GW-2S GW-3S GW-3D GW-4S GW-4S(Dup) GW-4D Sampling Date 08/19/04 08/19/04 08/19/04 08/19/04 08/19/04 08/19/04 08/19/04 Modified TO-15 GC/MS Full Scan Freon Freon Vinyl Chloride ND 0.81 ND Chloroethane ND ND ND 13 ND ND 21 Freon ND ND ND ND ND ND Ethanol ND ND ND 92 1,1-Dichloroethene ND ND ND ND ND Acetone Propanol Carbon Disulfide trans-1,2-dichloroethene ND ND ND ND Hexane ,1-Dichloroethane ND ND ND Butanone (Methyl Ethyl Ketone) ND 290 ND cis-1,2-dichloroethene ND ND 760 Chloroform 27 ND 1.8 ND ND ND ND Cyclohexane ,2,4-Trimethylpentane Benzene Heptane ND ND Trichloroethene ND Bromodichloromethane 0.72 ND ND ND ND ND ND #S Tetrachloroethene Ethyl Benzene ND ND 0.87 ND m,p-xylene o-xylene ND ND Styrene ND ND Cumene ND ND ND ND Ethyltoluene ND ND 1,3,5-Trimethylbenzene ND ND ND ND ND 0.74 ND 1,2,4-Trimethylbenzene ND ND Notes: ND = Not Detected. Lab Blank = All ND Z:\H&A\1081 Colusa Landfills\Evans Road\2012\1S2012\Report\Evans 1S2012 Tables.xls

50 Table 13. TOLERANCE INTERVAL ANALYSIS March Mar Evans Road Landfill Summary Report Monitored Parameter Concentration Limit Observed Concentrations in Down-gradient and Cross-gradient Wells M-1A M-1B M-3A M-4 M-5 TDS (mg/l) Chloride (mg/l) Sulfate (mg/l) Nitrate as Nitrogen (mg/l) (J) (J) ph EC (mhos/cm) Turbidity (NTU) J - Detected but below the Reporting Limit; therefore, result is an estimated concentration, detected but not quantified (DNQ). Bold values indicate observations which exceed the concentration limit. Concentration Limits calculated with parameter data sets from M-4. Z:\H&A\1081 Colusa Landfills\Evans Road\2012\1S2012\Report\Evans 1S2012 Tables.xls

51 APPENDIX A GRAPHICAL SUMMARIES OF GROUNDWATER MONITORING PARAMETERS

52 SELECTED PARAMETERS, MONITORING WELL M-1A EVANS ROAD LANDFILL Jul-98 Oct-98 Jan-99 Apr-99 Jul-99 Oct-99 Jan-00 Apr-00 Jul-00 Oct-00 Jan-01 Apr-01 Jul-01 Oct-01 Jan-02 Apr-02 Jul-02 Oct-02 Jan-03 Apr-03 Jul-03 Oct-03 Jan-04 Apr-04 Jul-04 Oct-04 Jan-05 Apr-05 Jul-05 Oct-05 Jan-06 Apr-06 Jul-06 Oct-06 Jan-07 Apr-07 Jul-07 Oct-07 Jan-08 Apr-08 Jul-08 Oct-08 Jan-09 Apr-09 Jul-09 Oct-09 Jan-10 Apr-10 Jul-10 Oct-10 Jan-11 Apr-11 Jul-11 Oct-11 Jan-12 Apr-12 Z:\H&A\1081 Colusa Landfills\Evans Road\2012\1S2012\Report\Evans 1S2012 Tables.xls Chloride, Nitrate as N, and Sulfate (mg/l) TDS (mg/l) and Electrical Conductivity (mhos/cm) Chloride Nitrate as Nitrogen Sulfate Total Dissolved Solids Electrical Conductivity

53 SELECTED PARAMETERS, MONITORING WELL M-1A EVANS ROAD LANDFILL Feb-03 Apr-03 Jun-03 Aug-03 Oct-03 Dec-03 Feb-04 Apr-04 Jun-04 Aug-04 Oct-04 Dec-04 Feb-05 Apr-05 Jun-05 Aug-05 Oct-05 Dec-05 Feb-06 Apr-06 Jun-06 Aug-06 Oct-06 Dec-06 Feb-07 Apr-07 Jun-07 Aug-07 Oct-07 Dec-07 Feb-08 Apr-08 Jun-08 Aug-08 Oct-08 Dec-08 Feb-09 Apr-09 Jun-09 Aug-09 Oct-09 Dec-09 Feb-10 Apr-10 Jun-10 Aug-10 Oct-10 Dec-10 Feb-11 Apr-11 Jun-11 Aug-11 Oct-11 Dec-11 Feb-12 Apr-12 Z:\H&A\1081 Colusa Landfills\Evans Road\2012\1S2012\Report\Evans 1S2012 Tables.xls Bicarbonate (mg/l) Sodium and Magnesium (mg/l) Bicarbonate Sodium Magnesium

54 SELECTED PARAMETERS, MONITORING WELL M-1B EVANS ROAD LANDFILL Z:\H&A\1081 Colusa Landfills\Evans Road\2012\1S2012\Report\Evans 1S2012 Tables.xls Chloride, Nitrate as N, and Sulfate (mg/l) Jun-03 Sep-03 Dec-03 Mar-04 Jun-04 Sep-04 Dec-04 Mar-05 Jun-05 Sep-05 Dec-05 Mar-06 Jun-06 Sep-06 Dec-06 Mar-07 Jun-07 Sep-07 Dec-07 Mar-08 Jun-08 Sep-08 Dec-08 Mar-09 Jun-09 Sep-09 Dec-09 Mar-10 Jun-10 Sep-10 Dec-10 Mar-11 Jun-11 Sep-11 Dec-11 Mar-12 TDS (mg/l) and Electrical Conductivity (mmhos/cm) Chloride Nitrate as Nitrogen Sulfate Total Dissolved Solids Electrical Conductivity

55 SELECTED PARAMETERS, MONITORING WELL M-1B EVANS ROAD LANDFILL Z:\H&A\1081 Colusa Landfills\Evans Road\2012\1S2012\Report\Evans 1S2012 Tables.xls Bicarbonate (mg/l) Feb-03 May-03 Aug-03 Nov-03 Feb-04 May-04 Aug-04 Nov-04 Feb-05 May-05 Aug-05 Nov-05 Feb-06 May-06 Aug-06 Nov-06 Feb-07 May-07 Aug-07 Nov-07 Feb-08 May-08 Aug-08 Nov-08 Feb-09 May-09 Aug-09 Nov-09 Feb-10 May-10 Aug-10 Nov-10 Feb-11 May-11 Aug-11 Nov-11 Feb-12 Sodium and Magnesium (mg/l) Bicarbonate Sodium Magnesium

56 SELECTED PARAMETERS, MONITORING WELL M-3A EVANS ROAD LANDFILL Jul-98 Oct-98 Jan-99 Apr-99 Jul-99 Oct-99 Jan-00 Apr-00 Jul-00 Oct-00 Jan-01 Apr-01 Jul-01 Oct-01 Jan-02 Apr-02 Jul-02 Oct-02 Jan-03 Apr-03 Jul-03 Oct-03 Jan-04 Apr-04 Jul-04 Oct-04 Jan-05 Apr-05 Jul-05 Oct-05 Jan-06 Apr-06 Jul-06 Oct-06 Jan-07 Apr-07 Jul-07 Oct-07 Jan-08 Apr-08 Jul-08 Oct-08 Jan-09 Apr-09 Jul-09 Oct-09 Jan-10 Apr-10 Jul-10 Oct-10 Jan-11 Apr-11 Jul-11 Oct-11 Jan-12 Apr-12 Z:\H&A\1081 Colusa Landfills\Evans Road\2012\1S2012\Report\Evans 1S2012 Tables.xls Chloride, Nitrate as N, and Sulfate (mg/l) TDS (mg/l) and Electrical Conductivity (mmhos/cm) Chloride Nitrate as Nitrogen Sulfate Total Dissolved Solids Electrical Conductivity

57 SELECTED PARAMETERS, MONITORING WELL M-3A EVANS ROAD LANDFILL Z:\H&A\1081 Colusa Landfills\Evans Road\2012\1S2012\Report\Evans 1S2012 Tables.xls Bicarbonate (mg/l) Jan-03 Apr-03 Jul-03 Oct-03 Jan-04 Apr-04 Jul-04 Oct-04 Jan-05 Apr-05 Jul-05 Oct-05 Jan-06 Apr-06 Jul-06 Oct-06 Jan-07 Apr-07 Jul-07 Oct-07 Jan-08 Apr-08 Jul-08 Oct-08 Jan-09 Apr-09 Jul-09 Oct-09 Jan-10 Apr-10 Jul-10 Oct-10 Jan-11 Apr-11 Jul-11 Oct-11 Jan-12 Apr-12 Sodium and Magnesium (mg/l) Bicarbonate Sodium Magnesium

58 SELECTED PARAMETERS, MONITORING WELL M-4 EVANS ROAD LANDFILL Jul-98 Oct-98 Jan-99 Apr-99 Jul-99 Oct-99 Jan-00 Apr-00 Jul-00 Oct-00 Jan-01 Apr-01 Jul-01 Oct-01 Jan-02 Apr-02 Jul-02 Oct-02 Jan-03 Apr-03 Jul-03 Oct-03 Jan-04 Apr-04 Jul-04 Oct-04 Jan-05 Apr-05 Jul-05 Oct-05 Jan-06 Apr-06 Jul-06 Oct-06 Jan-07 Apr-07 Jul-07 Oct-07 Jan-08 Apr-08 Jul-08 Oct-08 Jan-09 Apr-09 Jul-09 Oct-09 Jan-10 Apr-10 Jul-10 Oct-10 Jan-11 Apr-11 Jul-11 Oct-11 Jan-12 Apr-12 Z:\H&A\1081 Colusa Landfills\Evans Road\2012\1S2012\Report\Evans 1S2012 Tables.xls Chloride, Nitrate as N, and Sulfate (mg/l) TDS (mg/l) and Electrical Conductivity (mmhos/cm) Chloride Nitrate as Nitrogen Sulfate Total Dissolved Solids Electrical Conductivity

59 SELECTED PARAMETERS, MONITORING WELL M-4 EVANS ROAD LANDFILL Z:\H&A\1081 Colusa Landfills\Evans Road\2012\1S2012\Report\Evans 1S2012 Tables.xls Bicarbonate (mg/l) Jan-03 Apr-03 Jul-03 Oct-03 Jan-04 Apr-04 Jul-04 Oct-04 Jan-05 Apr-05 Jul-05 Oct-05 Jan-06 Apr-06 Jul-06 Oct-06 Jan-07 Apr-07 Jul-07 Oct-07 Jan-08 Apr-08 Jul-08 Oct-08 Jan-09 Apr-09 Jul-09 Oct-09 Jan-10 Apr-10 Jul-10 Oct-10 Jan-11 Apr-11 Jul-11 Oct-11 Jan-12 Apr-12 Sodium and Magnesium (mg/l) Bicarbonate Sodium Magnesium

60 SELECTED PARAMETERS, MONITORING WELL M-5 EVANS ROAD LANDFILL Z:\H&A\1081 Colusa Landfills\Evans Road\2012\1S2012\Report\Evans 1S2012 Tables.xls Chloride, Nitrate as N, and Sulfate (mg/l) Jan-03 Apr-03 Jul-03 Oct-03 Jan-04 Apr-04 Jul-04 Oct-04 Jan-05 Apr-05 Jul-05 Oct-05 Jan-06 Apr-06 Jul-06 Oct-06 Jan-07 Apr-07 Jul-07 Oct-07 Jan-08 Apr-08 Jul-08 Oct-08 Jan-09 Apr-09 Jul-09 Oct-09 Jan-10 Apr-10 Jul-10 Oct-10 Jan-11 Apr-11 Jul-11 Oct-11 Jan-12 Apr-12 TDS (mg/l) and Electrical Conductivity (mmhos/cm) Chloride Nitrate as Nitrogen Sulfate Total Dissolved Solids Electrical Conductivity

61 SELECTED PARAMETERS, MONITORING WELL M-5 EVANS ROAD LANDFILL Z:\H&A\1081 Colusa Landfills\Evans Road\2012\1S2012\Report\Evans 1S2012 Tables.xls Bicarbonate (mg/l) Jan-03 Apr-03 Jul-03 Oct-03 Jan-04 Apr-04 Jul-04 Oct-04 Jan-05 Apr-05 Jul-05 Oct-05 Jan-06 Apr-06 Jul-06 Oct-06 Jan-07 Apr-07 Jul-07 Oct-07 Jan-08 Apr-08 Jul-08 Oct-08 Jan-09 Apr-09 Jul-09 Oct-09 Jan-10 Apr-10 Jul-10 Oct-10 Jan-11 Apr-11 Jul-11 Oct-11 Jan-12 Apr-12 Sodium and Magnesium (mg/l) Bicarbonate Sodium Magnesium

62 APPENDIX B MONITORING WELL SAMPLING DATA SHEETS

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70 APPENDIX C GROUNDWATER HYDROGRAPHS

71 DISCHARGER'S HYDROGRAPH: M-1A Evans Road Landfill, Colusa County Top of screened interval Bottom of screened interval Pump intake Bottom of Well Groundwater Elevation May-98 Sep-98 Jan-99 May-99 Sep-99 Jan-00 May-00 Sep-00 Jan-01 May-01 Sep-01 Jan-02 May-02 Sep-02 Jan-03 May-03 Sep-03 Jan-04 May-04 Sep-04 Jan-05 May-05 Sep-05 Jan-06 May-06 Sep-06 Jan-07 May-07 Sep-07 Jan-08 May-08 Sep-08 Jan-09 May-09 Sep-09 Jan-10 May-10 Sep-10 Jan-11 May-11 Sep-11 Jan-12 Z:\H&A\1081 Colusa Landfills\Evans Road\2012\1S2012\Report\Evans 1S2012 Tables.xls Elevation (ft. above msl)

72 DISCHARGER'S HYDROGRAPH: M-1B Evans Road Landfill, Colusa County Top of screened interval Bottom of screened interval Pump intake Bottom of Well Groundwater Elevation Z:\H&A\1081 Colusa Landfills\Evans Road\2012\1S2012\Report\Evans 1S2012 Tables.xls Elevation (ft. above msl) Jan-03 May-03 Sep-03 Jan-04 May-04 Sep-04 Jan-05 May-05 Sep-05 Jan-06 May-06 Sep-06 Jan-07 May-07 Sep-07 Jan-08 May-08 Sep-08 Jan-09 May-09 Sep-09 Jan-10 May-10 Sep-10 Jan-11 May-11 Sep-11 Jan-12

73 DISCHARGER'S HYDROGRAPH: M-3A Evans Road Landfill, Colusa County Top of screened interval Bottom of screened interval Pump intake Bottom of Well Groundwater Elevation May-98 Sep-98 Jan-99 May-99 Sep-99 Jan-00 May-00 Sep-00 Jan-01 May-01 Sep-01 Jan-02 May-02 Sep-02 Jan-03 May-03 Sep-03 Jan-04 May-04 Sep-04 Jan-05 May-05 Sep-05 Jan-06 May-06 Sep-06 Jan-07 May-07 Sep-07 Jan-08 May-08 Sep-08 Jan-09 May-09 Sep-09 Jan-10 May-10 Sep-10 Jan-11 May-11 Sep-11 Jan-12 Z:\H&A\1081 Colusa Landfills\Evans Road\2012\1S2012\Report\Evans 1S2012 Tables.xls Elevation (ft. above msl)

74 DISCHARGER'S HYDROGRAPH: M-4 Evans Road Landfill, Colusa County NOTE: SCREEN INTERVAL ELEVATIONS UNKNOWN FOR M-4 Pump intake Bottom of Well Groundwater Elevation Jan-95 May-95 Sep-95 Jan-96 May-96 Sep-96 Jan-97 May-97 Sep-97 Jan-98 May-98 Sep-98 Jan-99 May-99 Sep-99 Jan-00 May-00 Sep-00 Jan-01 May-01 Sep-01 Jan-02 May-02 Sep-02 Jan-03 May-03 Sep-03 Jan-04 May-04 Sep-04 Jan-05 May-05 Sep-05 Jan-06 May-06 Sep-06 Jan-07 May-07 Sep-07 Jan-08 May-08 Sep-08 Jan-09 May-09 Sep-09 Jan-10 May-10 Sep-10 Jan-11 May-11 Sep-11 Jan-12 Z:\H&A\1081 Colusa Landfills\Evans Road\2012\1S2012\Report\Evans 1S2012 Tables.xls Elevation (ft. above msl)

75 DISCHARGER'S HYDROGRAPH: M-5 Evans Road Landfill, Colusa County Top of screened interval Bottom of screened interval Pump intake Bottom of Well Groundwater Elevation Z:\H&A\1081 Colusa Landfills\Evans Road\2012\1S2012\Report\Evans 1S2012 Tables.xls Elevation (ft. above msl) Jan-03 May-03 Sep-03 Jan-04 May-04 Sep-04 Jan-05 May-05 Sep-05 Jan-06 May-06 Sep-06 Jan-07 May-07 Sep-07 Jan-08 May-08 Sep-08 Jan-09 May-09 Sep-09 Jan-10 May-10 Sep-10 Jan-11 May-11 Sep-11 Jan-12

76 APPENDIX D LABORATORY ANALYTICAL REPORT AND CHAIN OF CUSTODY DOCUMENTATION

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