Loading...
HomeMy WebLinkAboutAmendment to Professional Services Agreement with Tetra Tech Ground Water Monitoring_6 Commission Memorandum REPORT TO: Honorable Mayor and City Commission FROM: Craig Woolard, Director of Public Works Richard Hixson, City Engineer SUBJECT: Amendment to Professional Services Agreement with Tetra Tech Inc. For continued post-closure ground water monitoring at the Story Mill Landfill. MEETING DATE: February 24, 2014 AGENDA ITEM TYPE: Consent RECOMMENDATION: Authorize City Manager to sign. BACKGROUND: The attached work plan was prepared by Tetra Tech on behalf of the City of Bozeman to address groundwater issues at the Bozeman Landfill (also known as the Story Mill landfill) identified by the Montana Department of Environmental Quality (DEQ) in their letters dated August 30, November 5, 2013 and January 16, 2014. The purpose of this groundwater investigation is to better understand the extent of impacted groundwater and its possible influence on volatile organic compound (VOC) concentrations in soil gas south and west of the unlined cell. This work plan is intended to ultimately support the development of a Revised Corrective Measures Assessment (RCMA) for the subject site. The proposed cost for this task order is $132,483.25. Included in this task order are all costs for installation of 8 groundwater monitoring wells and one complete round of sampling, testing and reporting. The wells will be finished at grade and will remain available for future use. FISCAL EFFECTS: The entire project will be funded through the Solid Waste Landfill Closure/Post-Closure Fund. ALTERNATIVES: As suggested by the City Commission. Attachments: Task Order from Tetra Tech Inc. Report compiled on: 2/10/14 32 Task Order Work Plan for Groundwater Investigation Bozeman Landfill Class II/ License #196 Bozeman Landfill Bozeman, Montana January 31, 2014 CLIENT: CONSULTANT: The City of Bozeman Tetra Tech, Inc. P.O. Box 1230 851 Bridger Drive, Ste 6 Bozeman, Montana 59711-1230 Bozeman, MT 59715 Attention: Mr. Rick Hixson Attention: Mr. Mark F. Pearson INTRODUCTION This work plan was prepared by Tetra Tech on behalf of the City of Bozeman to address groundwater issues at the Bozeman Landfill (also known as the Story Mill landfill) identified by the Montana Department of Environmental Quality (DEQ) in their letters dated August 30, November 5, 2013 and January 16, 2014. The purpose of this groundwater investigation is to better understand the extent of impacted groundwater and its possible influence on volatile organic compound (VOC) concentrations in soil gas south and west of the unlined cell. This work plan is intended to ultimately support the development of a Revised Corrective Measures Assessment (RCMA) for the subject site. The former landfill consists of two waste cells, the Unlined Closed Cell and the Lined Closed Cell as shown in Figure 1. The City of Bozeman has been conducting groundwater monitoring activities since the 1980s, landfill gas (LFG) mitigation since 1997, and an investigation of soil gas migration from the landfill site since early in 2013. The City operates a LFG extraction system in the Unlined Closed Cell and is in the process of installing individual sub-slab depressurization systems in the residences of Bridger Creek Subdivision Phase 3. This data will also allow Tetra Tech to confirm or modify its conceptual model of soil gas transport. Tetra Tech’s current model identifies landfill gas migration directly from the Unlined Cell as the primary transport mechanism for VOCs into off-site neighborhoods. Current data does not indicate that a significant contaminated groundwater plume exists off of the landfill property, however, this investigation will attempt to confirm whether groundwater could be a source of VOCs in soil gas. The data from this investigation will also support the development and comparison of remedial alternatives during the Revised CMA process. SCOPE OF WORK This work plan proposes the installation and sampling of nine additional groundwater monitoring wells at locations shown on Figure 2 plus one additional well between Turnberry Court and Caddie Court, which has not been located as of yet. Table 1 provides information on the location, target completion depths, and purpose/justification for each well. Details of this task are described below: 33 Work Plan – Groundwater Investigation Bozeman Landfill, Bozeman, Montana January 31, 2014 Page 2 of 4 Field Location of Well Locations and Underground Utility Clearance The proposed wells will be located on the south margin of the landfill property, in a City of Bozeman easement where existing well LF-3 is located, and in the public right-of-way (boulevard - between the street curb and the sidewalk) of the Bridger Creek subdivisions. These locations will be staked and then the Underground Utility Notification Center will be notified to clear all of the locations of underground utilities. Location MW-20 is currently proposed to be located on private property, hence, it will be dependent upon the landowner signing an access agreement. If landowner access is not obtained, the location will be moved slightly south to the McIIhattan Road public right-of-way. Drilling and Installation of Monitoring Wells The field investigation will consist of drilling and completion of up to nine groundwater monitoring wells. Details are provided below: ■ Completion depths and length of screen across the groundwater intercept have been estimated (Table 1). ■ The hollow stem auger (HSA) drilling technique will be used based on site suitability in previous drilling and well installation at the site. In addition, this drilling technique can return high quality soil samples and can be more economical than alternative drilling methods. ■ Tetra Tech personnel will supervise the drilling and completion of the monitoring wells; log the soil/geologic materials during drilling; note any changes in lithology, drilling rate, water occurrence, and other conditions; and confirm the intersection with groundwater. ■ Upon reaching the target depth, each well will be constructed of 2-inch diameter, schedule 40 PVC with 0.020-inch slots in the screened intervals. The screened interval will be placed across intersection of groundwater such that approximately one third of the screened length will be above the groundwater intercept and two thirds below the groundwater intercept. In addition to providing the PVC piping and well completion materials, the driller will install: 10-20 silica sand around the well screen to approximately one foot above top of well screen, a bentonite seal from top of sand pack to within 1.5 feet of grade, and stickup and locking well protector set in concrete grout. A flush- mounted traffic-rated well protector set in concrete grout will be used for wells located in the boulevard of the subdivisions. ■ Drilling equipment will be decontaminated between drill holes. Decontamination activities will be conducted on the landfill property. ■ Upon completion, wells will be developed, with a decontaminated submersible pump and disposable tubing, to remove fine sediment and establish a hydraulic connection with the aquifer. Development water will not be containerized. ■ Following completion, each drilling site will be returned to conditions prior to drilling, with the exception of vegetation, which will not be reestablished until summer 2014. ■ Following completion of the wells, surveying will be conducted to establish the location and top of casing elevation above mean sea level (AMSL) for each of the new wells. 34 Work Plan – Groundwater Investigation Bozeman Landfill, Bozeman, Montana January 31, 2014 Page 3 of 4 Groundwater Monitoring Following installation of the wells, groundwater monitoring will be conducted. Monitoring will be conducted on a quarterly basis for a minimum of four quarters. Groundwater monitoring activities will consist of field measurements and the collection of groundwater samples for laboratory analysis. Details of the monitoring are the following: ■ Field parameter measurements will consist of depth to groundwater measurements, temperature, pH, specific conductivity, dissolved oxygen, and oxidation reduction potential. A multi-parameter meter with a 20 meter cable to enable down-hole measurements of field parameters will be used to confirm adequate purging of each well has been completed. ■ Groundwater samples will typically be collected using a dedicated bailer. ■ Groundwater samples will be analyzed for VOCs in accordance with either EPA Method 8260 low level or EPA Method 524.2. In addition, during the first groundwater monitoring event samples will also be analyzed for cations, anions, alkalinity, iron, manganese and tritium. We are currently working with the laboratory to identify which method will achieve lower detection limits. Project and Database Management and Reporting Tetra Tech’s management team will consist of Kirk Miller as the Project Manager and Mark Pearson as the Assistant Project Manager. Project management will consist of contracting and scheduling a drilling company; equipment and materials procurement; site preparation; client, public, and regulatory liaison; and review/approval of invoicing among other activities. Data management will include validation and entry of data into the project database (Microsoft Access). This will, in turn, support generation of data tables, maps, and GIS analysis as needed throughout this phase and other phases of the project. Reporting A groundwater investigation report will be prepared following the installation of the wells and the first groundwater monitoring event. This report will contain a summary of field and laboratory results, a summary of all activities, conclusions, and recommendations for further investigation and/or monitoring. Groundwater monitoring reports will be prepared for the subsequent quarterly monitoring events and will be combined with the results of monitoring of the existing landfill monitoring wells. The fourth quarter monitoring report will contain a summary of all activities, conclusions, and recommendations for further investigation and/or monitoring. Subsequent monitoring events after one year will be determined based on project data needs at that time. Schedule Tetra Tech’s anticipated schedule to complete the groundwater investigation will be dependent upon the time it takes for the City and DEQ to come to agreement on the scope of this work plan, and the availability of a drilling company. However, it is anticipated that by mid-March 2014 drilling and well installation, along with the first monitoring event, will have been completed. The groundwater investigation report will be submitted within one month of receipt of laboratory results for the initial monitoring event. 35 Work Plan – Groundwater Investigation Bozeman Landfill, Bozeman, Montana January 31, 2014 Page 4 of 4 Compensation Estimated costs to complete the foregoing scope of services are not to exceed $132,483. A breakdown of these proposed expenditures is contained in the attached cost estimate. The services will be conducted on a time and materials basis. Special Conditions Execution of this Task Order constitutes acceptance of all terms and conditions contained in Tetra Tech’s Professional Services Agreement with the City of Bozeman, dated January 3, 1994 and Amendment Nos. 1, 2, 3, and 4 of the Professional Services Agreement dated July 31, 1995; January 1, 1996; March 17, 1997; and December 10, 2001, respectively. CLIENT: CONSULTANT: City of Bozeman Tetra Tech By: By: Its: Its: Sr. Project Manager Date: Date: January 31, 2014 NOTICE OF CONFIDENTIALITY This Task Order (including attachments) contains information confidential to Tetra Tech, Inc., its subsidiaries, and subcontractors. It is intended only for City of Bozeman to consider Tetra Tech providing professional services at the Bozeman Landfill. Any other use is prohibited, without the prior written consent of Tetra Tech. 36 TABLE 1 Proposed Groundwater Monitoring Wells Location, Purpose, and Completion Details Bozeman Landfill Groundwater Investigation Work Plan Bozeman, Montana December 10, 2013 Location Purpose or Justification Assumed Estimated Screen Screened Surface at site Depth to Total Length Interval Completion Groundwater Depth (feet)(feet)(feet)(feet) MW-17 Near SE corner of Unlined Cell Evaluate groundwater conditions associated with relatively high VOC concentrations in soil gas in this area. To evaluate groundwater flow directions and VOC concentrations in this area. 60 70 15 55-70 2-foot stick-up steel well protector MW-18 South of Unlined Cell Evaluate groundwater conditions associated with relatively high VOC concentrations in soil gas in this area. To evaluate groundwater flow directions and VOC concentrations in this area. 60 70 15 55-70 2-foot stick-up steel well protector MW-19 Adjacent to existing well LF-3 To provide a monitoring well at LF-3 that intersects the water table. Well will be screened across the first groundwater intercept at approx. 14 feet depth. Well LF-3 top of screen is approx. 17 feet below the water table. 14 24 15 9-24 2-foot stick-up steel well protector MW-20 Near residence MI-2, along Mclhattan Rd Evaluate whether VOCs observed in the subslab sample from the home at 2700 Mcilhattan Road is the result of contaminated groundwater in this area or vapor migration from the landfill. Also, to evaluate groundwater flow south of the landfill. 30 40 15 25-40 Flush-mount, steel well protector MW-21 Near intersection of McIlhattan Rd and Augusta Dr Evaluate whether VOCs observed in subslab samples from Phase 2 homes are the result of contaminated groundwater in this area or vapor migration from the landfill. Also to evaluate whether VOC sources not associated with the landfill exist upgradient of Bridger Creek Phase 2 Subdivision, in the Bridger Creek alluvium. 12 19 10 9-19 Flush-mount, steel well protector MW-22 On East part of Augusta Dr Evaluate whether VOCs observed in subslab samples from Phase 2 homes are the result of contaminated groundwater in this area or vapor migration from the landfill. Also, to provide data points to triangulate groundwater flow directions in this area. 8 15 10 5-15 Flush-mount, steel well protector MW-23 On West part of Augusta Dr Evaluate whether VOCs observed in subslab samples from Phase 2 homes are the result of contaminated groundwater in this area or vapor migration from the landfill. Also, to provide data points to triangulate groundwater flow directions in this area. 8 15 10 5-15 Flush-mount, steel well protector MW-24 On Story Mill Road south of Caddie Court Evaluate groundwater conditions associated with relatively high VOC concentrations in soil gas in the vicinity of Caddie Court. To evaluate groundwater flow directions and VOC concentrations in this area. 60 70 15 55-70 Flush-mount, steel well protector MW-25 On City Park Lands between Turnberry Court and Caddie Court Evaluate groundwater conditions associated with relatively high VOC concentrations in soil gas in the vicinity of Caddie Court. To evaluate groundwater flow directions and VOC concentrations in this area. 60 70 15 55-70 Flush-mount, steel well protector Proposed Well Tetra Tech 1/31/2014 Page 1 of 1 37 N:\PROJECTS\CITY OF BOZEMAN\Bozeman Landfill\114-710303 - Bozeman Landfill\CAD\SheetFiles\F-01-Site Location.dwg SAVED:2/21/13 PRINTED:2/21/13 BY:MARY.BELL0 Feet This Drawing, in the form transmitted, is the original work product of TETRA TECH. This drawing cannot be altered, revised or reproduced without the prior written consent of TETRA TECH. An original will be retained by TETRA TECH as the "record copy" for purposes of this project. TETRA TECH does not approve of or warrant these documents if any alteration or modification is made without TETRA TECH's written approval. Site Location Map Bozeman Sanitary Landfill Bozeman, Montana FIGURE 1 2000 December 2012114-710303From USGS 7.5' Bozeman Quad (1987) 114-710303.402 38 Datum: NAD83 StatePlane Montana 0 250 500 Feet Proposed Groundwater Monitoring WellsGroundwater Investigation Work PlanBozeman LandfillBozeman, MontanaFIGURE 2N:\PROJECTS\CITY OF BOZEMAN\Bozeman Landfill\114-710303 - Bozeman Landfill\GIS\ArcMap\GroundwaterInvestigation.mxd² !U Groundwater Monitoring Well !(Proposed Monitoring Well !A Soil Gas Probe New Residential Construction 39 ATTACHMENT B ESTIMATED BUDGET WORK PLAN FOR GROUNDWATER INVESTIGATION BOZEMAN LANDFILL CLASS II / LICENSE #196 BOZEMAN, MONTANA Date Submitted: 1/29/2014 Field Locations of Well Locations and Underground Utility Clearance Field Work Units Rate Cost Project Manager/Senior Hydrogeologist, per hour 1 $170.00 $170.00 Hydrogeologist, per hour 24 $95.00 $2,280.00 Clerical, per hour 2 $55.00 $110.00 Subtotal $2,560.00 TOTAL $2,560.00 Drilling and Installation of Monitoring Wells Field Work Units Rate Cost Project Manager/Senior Hydrogeologist, per hour 4 $170.00 $680.00 Hydrogeologist, per hour 120 $95.00 $11,400.00 Tetra Tech Vehicle Mileage, per mile 550 $0.56 $308.00 Per Diem and Lodging, per person per day 10 $140.00 $1,400.00 Clerical, per hour 4 $55.00 $220.00 Subtotal $14,008.00 DIRECT COSTS Contracted Drilling Services Drill/complete nine groundwater monitoring wells. Estimate 383 feet of drilling. Haz Tech Drilling Bid (1/11/2014 Bid) Mob/Demob, lump sum 1 $1,500.00 $1,500.00 Support Truck, per day 11 $150.00 $1,650.00 Perdiem, per crew day 11 $46.00 $506.00 Lodging, per night 10 $400.00 $4,000.00 Drilling & Related Activities, per hour 90 $195.00 $17,550.00 2-inch Well Installation, per foot (materials only)383 $17.00 $6,511.00 Flush Covers with Concrete, each 6 $100.00 $600.00 Steel Stick-up Covers with Concrete, each 3 $175.00 $525.00 Tool/Bit Wear, per foot 383 $3.50 $1,340.50 Steam Cleaner/Pressure Washer, per day 11 $50.00 $550.00 Standby/Well Development/Weather Delay, per hour 10 $150.00 $1,500.00 Crew Breaks, each trip 0 $1,250.00 $0.00 TetraTech Subcontractor Markup (10%)$3,623.25 Subtotal $39,855.75 Other Direct Costs Tetra Tech Vehicle Mileage, per mile 20 $0.56 $11.20 Per Diem and Lodging, per person per day 5 $140.00 $700.00 Traffic Control Signage, estimate 1 $300.00 $300.00 Sample Bags and Storage Containers, estimate 1 $50.00 $50.00 Professional Surveying of Well Elevations, estimate 0 $0.00 $0.00 Subtotal $1,061.20 TOTAL WELL INSTALLATION COSTS $57,484.95 Tetra Tech 40 ATTACHMENT B ESTIMATED BUDGET WORK PLAN FOR GROUNDWATER INVESTIGATION BOZEMAN LANDFILL CLASS II / LICENSE #196 BOZEMAN, MONTANA Date Submitted: 1/31/2014 Groundwater Monitoring Field Work Units Rate Cost Project Manager/Senior Hydrogeologist, per hour 2 $170.00 $340.00 Hydrogeologist, per hour 40 $95.00 $3,800.00 Per Diem and Lodging, per person per day 4 $140.00 $560.00 Staff Field Personnel, per hour 16 $65.00 $1,040.00 Subtotal per Monitoring Event $5,740.00 DIRECT COSTS Tetra Tech Vehicle Mileage, per mile 50 $0.60 $30.00 Water Level Meter, per week 1 $75.00 $75.00 YSI Multi-Meter, per week 1 $300.00 $300.00 Submersible pump (Proactive Monsoon® DTW up to 120 feet depth), each 1 $455.00 $455.00 Note: Dedicated pump purchase is included in the event that a Bozeman Landfill groundwater monitoring pump breaks down Sampling Disposables - Filter, each 10 $18.00 $180.00 Sampling Disposables - Bailer, each 9 $4.75 $42.75 Sampling Disposables - Low-flow tip, each 10 $2.50 $25.00 Sampling Disposables - pump tubing, per foot 250 $0.25 $62.50 Sampling Disposables - Miscellaneous, each 10 $3.00 $30.00 Miscellaneous Shipping, estimate 1 $100.00 $100.00 Lab Sample Shipping (overnight to lab), estimate 1 $150.00 $150.00 Lab Analysis (VOCs, Method 8260 Low Level), each 18 $95.00 $1,710.00 Tetra Tech 10% markup on Subcontractors, Equipment, and Materials $275.53 Subtotal per Monitoring Event $3,435.78 Additional Analysis for First Monitoring Event Lab Analysis (inorganics - cations, anions, alkalinity)16 $72.00 $1,152.00 Lab Analysis (inorganics - iron & manganese), each 10 $19.00 $190.00 Lab Analysis (inorganics - tritium), each 10 $19.00 $190.00 Tetra Tech 10% markup on Subcontractors, Equipment, and Materials $153.20 Subtotal per Monitoring Event $1,685.20 GROUNDWATER MONITORING TOTAL $38,388.30 Project and Database Management Project Manager/Senior Hydrogeologist, per hour 40 $170.00 $6,800.00 Hydrogeologist, per hour 24 $95.00 $2,280.00 Environmental Chemist, per hour 32 $110.00 $3,520.00 Database/GIS Analyst, per hour 64 $100.00 $6,400.00 Administrative Personnel, per hour 16 $55.00 $880.00 Subtotal $19,880.00 PROJECT AND DATABASE MANAGEMENT TOTAL $19,880.00 Reporting Project Manager/Senior Hydrogeologist, per hour 8 $170.00 $1,360.00 Hydrogeologist, per hour 120 $95.00 $11,400.00 Tetra Tech 41 Environmental Chemist, per hour 8 $110.00 $880.00 Database/GIS Analyst, per hour 24 $100.00 $2,400.00 Administrative Personnel, per hour 8 $55.00 $440.00 DIRECT COSTS Photocopies, estimate 500 $0.10 $50.00 Reprographics, estimate 4 $50.00 $200.00 Subtotal $16,730.00 REPORTING TOTAL $16,730.00 TOTAL OF ALL TASKS $132,483.25 Tetra Tech 42