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Home My WebLink AboutDSHW-2018-004921 - 0901a06880834592„,,, Linagement and Raciation Controi Stantec Stantec Consulting Services inc. 3995 South 700 East; Ste 300 Salt Lake City, UT 84107 Tel: (801) 261-0090 Fax: (801) 266-1671 tv1AY 3 1 2018 V-HIAF201 0-0045)2 / May 25, 2018 Mr. Hao Zhu Utah Department of Environmental Quality Division of Waste Management and Radiation Control 195 North 1950 West Salt Lake City, UT 84114 RE: Phytoremediation Pilot Study Work Plan Former Varian Facility, 1678 Pioneer Road, Salt Lake City, Utah 84104 Dear Mr. Zhu, On Behalf of Varian Medical Systems (Varian), Stantec Consulting Services, Inc. (Stantec), has prepared the following Phytoremediation Pilot Study Work Plan (Work Plan) for the Former Varian Facility property (now Varex Imaging) at 1678 Pioneer Road, Salt Lake City, Utah (the Site). Site preparation, tree plantings, and irrigation system installation were completed at the Site the week of May 30, 2018. The installation of additional monitoring wells and performance monitoring will be initiated following Utah Department of Environmental Quality, Division of Waste Management and Radiation Control's (DWMRC's) approval of the Work Plan. Should you have any questions or comments on the Work Plan or to set up a conference call following the DWMRC's review of the Work Plan, please call me at (801) 230-6646. Sincerely, ----rif7014144 `iktatrz/ Tom Fendler Senior Geologist Stantec 3995 South 700 East Suite 300, Salt Lake City UT 84107-2540 Phone: (801) 743-4843 Cell: (801) 230-6646 Tom.Fendler@stantec.com Design with community in mind 5 Mr. Hao Zhu February 21, 2018 Page 2 of 2 C: Scott T. Anderson UDEQ (2 copies) John Buchanan VMS (by email) H. Michael Keller VanCott. Bagley and McCarthy (by email) Angus McGrath Stantec (by email) Design with community in mind PHYTOREMEDIATION PILOT STUDY WORK PLAN Former Varian Medical Systems Facility 1678 Pioneer Road Salt Lake City, Utah May 25, 2018 Prepared for: Hao Zhu Division of Waste Management and Radiation Control Utah Department of Environmental Quality 195 North 1950 West, Second Floor Salt Lake City, Utah Prepared by: Stantec Consulting Services, Inc. 3995 South 700 East, Suite 300 Salt Lake City, Utah Sign-off Sheet This document entitled Phytoremediation Pilot Study Work Plan was prepared by Stantec Consulting Services Inc. (“Stantec”) for the account of Varian Medical Systems (the “Client”). Any reliance on this document by any third party is strictly prohibited. The material in it reflects Stantec’s professional judgment in light of the scope, schedule and other limitations stated in the document and in the contract between Stantec and the Client. The opinions in the document are based on conditions and information existing at the time the document was published and do not take into account any subsequent changes. In preparing the document, Stantec did not verify information supplied to it by others. Any use which a third party makes of this document is the responsibility of such third party. Such third party agrees that Stantec shall not be responsible for costs or damages of any kind, if any, suffered by it or any other third party as a result of decisions made or actions taken based on this document. Prepared by (signature) Anna Skinner, EIT Engineering Staff Reviewed by (signature) Thomas Fendler, PG Senior Geologist Reviewed by (signature) Angus McGrath Principal Geochemist PHYTOREMEDIATION PILOT STUDY WORK PLAN Table of Contents 1.0 INTRODUCTION ............................................................................................................ 1 1.1 SITE HISTORY .............................................................................................................. 1 1.2 SITE SPECIFIC CONDITIONS ....................................................................................... 1 1.3 PILOT STUDY OBJECTIVES ......................................................................................... 2 2.0 DESIGN ......................................................................................................................... 2 3.0 IMPLEMENTATION ....................................................................................................... 3 3.1 SITE PREPARATION ..................................................................................................... 3 3.2 TREE PLANTINGS......................................................................................................... 3 3.3 IRRIGATION SYSTEM ................................................................................................... 3 3.4 OPERATION AND MAINTENANCE ............................................................................... 4 4.0 SCHEDULE.................................................................................................................... 4 5.0 PERFORMANCE MONITORING ................................................................................... 4 6.0 REPORTING .................................................................................................................. 5 7.0 MAINTENANCE OF SITE MANAGEMENT OBJECTIVES ............................................ 5 LIST OF TABLES LIST OF FIGURES Figure 1 – Site Vicinity Map Figure 2 – Phytoremediation Pilot Study Area Groundwater Monitoring Wells LIST OF APPENDICES Appendix A – Utah Department of Environmental Quality, Division of Waste Management and Remediation Control, Electronic Correspondence Appendix B – Sand-Creek Consulting, Inc. Phytoremediation Pilot Study Design and Planting Plan PHYTOREMEDIATION PILOT STUDY WORK PLAN Former Varian Medical Systems Facility 1 1.0 INTRODUCTION This Phytoremediation Pilot Study Work Plan for the Former Varian Medical Systems (Varian) Facility located at 1678 Pioneer Road in Salt Lake City, Utah (the Site, Figure 1) was prepared in accordance with the remedial objectives described in electronic communication with the Utah Department of Environmental Quality (UDEQ) Division of Waste Management and Radiation Control (DWMRC) included as Appendix A. This work plan describes the remedial objectives and methods for the implementation and evaluation of a phytoremediation pilot study at the Site. 1.1 SITE HISTORY The first documented construction on the Site took place in 1941 as a Department of Defense facility which was known as the Utah Ordnance Plant. The current Varex Imaging (Varex) building is used to manufacture X-ray products; its footprint is the result of several additions with the most recent completed in 2016. Initial soil and groundwater investigations at the Site were conducted between 1983 and 1991 by JH Kleinfelder and Associates. Additional investigations and a risk assessment were completed by Montgomery Watson between 1991 and 1997. In April 2009 and October 2010, vapor intrusion studies were conducted to evaluate the potential risk of vapors from volatile organic compounds (VOCs) to migrate into the Varian building as well as five buildings located on the adjacent US Construction property, north of the property. In 2013, Stantec conducted additional characterization of the Northern and Western Plume areas (see Figure 2). Remediation activities began at the Site in 1994 with an interim remedial measure to initiate groundwater extraction and treatment of the trichloroethene (TCE) plume; a full-scale groundwater extraction and treatment system was implemented in 2000. In late 2007, a dual phase extraction and soil vapor extraction system was installed immediately adjacent to the west side of the Varian building to address a TCE "hot spot". Semiannual groundwater monitoring is ongoing. A complete site history is presented in the Third Five-Year Review Report, July 2010 – June 2015 document dated March 23, 2016. 1.2 SITE SPECIFIC CONDITIONS Soils observed in the Western Plume pilot study area generally consist of poorly and well graded sands with occasional silty sand or silt lenses to approximately 13 feet below ground surface (bgs). Clay with sandy and silty clay lenses are observed from approximately 13 to 18 feet bgs, and a highly, plastic, dense clay with silty sand lenses are observed from approximately 18 to 30 feet bgs. Two distinct hydrogeological groundwater zones exist: an unconfined, "shallow" zone in the deposits above the silty clay which extend from approximately 13 to 18 feet bgs and a semiconfined, "intermediate" zone in the sand beneath the silty clay which extends from approximately 18 to 30 feet bgs. A relatively strong upward vertical gradient exists between the shallow and intermediate zones. Horizontal flow in the shallow groundwater is generally to the north- northwest. The static water level is approximately seven to 12 feet bgs. PHYTOREMEDIATION PILOT STUDY WORK PLAN Former Varian Medical Systems Facility 2 Two separated TCE plumes are present including the on-Site Western Plume and the off-Site Northern Plume located on the US Construction Property (Figure 1). A Utah Power and Light right-of-way is located west of the Site and is downgradient of the Western Plume. The US Construction and Shimizu properties are located north of the Site. The US Construction property is occupied by several businesses, including automobile and truck maintenance shops, a reconditioning shop for wooden pallets, general storage buildings, and an automobile impoundment lot run by the Salt Lake City Police Department. The Shimizu property is located downgradient from the Northern Plume and is primarily utilized for truck maintenance activities. Hydraulic containment of the TCE plume on the west side of the site is controlled by the West Extraction Trench and a slurry wall which protects the flood control ditch located on the western property boundary between the Site and the Utah Power and Light right-of-way. Hydraulic containment of the TCE plume to the north of the site is controlled by the North Extraction Trench. 1.3 PILOT STUDY OBJECTIVES The two main objectives of the Phytoremediation Pilot Study are to evaluate: 1) relative performance (growth, health, and water uptake) of the six varieties of hybrid cottonwood trees given the Site-specific conditions, and 2) overall performance of phytoremediation at reducing concentrations of TCE in groundwater and reducing the mass flux of TCE (all volatile organic compounds, VOCs) through the phytoremediation area. Phytoremediation will be considered a successful technology for the Site if full scale implementation is proven capable of replacing the Western Trench by preventing the off-Site migration of the TCE plume. 2.0 DESIGN The pilot study area is located in the distal portion of the Western Plume and is approximately 80 feet wide by 250 feet long (Appendix B – Figure 2). Six varieties of hybrid cottonwoods will be planted, each with 15 replicates (90 total trees to be planted). These six varieties include: • one pure eastern cottonwood, Populus deltoides, variety siouxland; • one pure western cottonwood Populous fremontii; • two varieties of P. deltoides X P. trichocarpa crosses: 15‐029 and 50‐197; and • two varieties of P. deltoides X P. nigra crosses: OP367 and DN21. The siouxland and Western cottonwood trees will all be males and will not produce cotton. The remaining varieties are sterile species crosses. Each variety will be planted in one row (six rows of 15 trees) with approximately 15 feet between the centerlines of each tree; the centerline of each row will be spaced 15 feet apart (see Appendix B – Figure 3). A complete design package for the phytoremediation pilot plantation is included in Appendix B. PHYTOREMEDIATION PILOT STUDY WORK PLAN Former Varian Medical Systems Facility 3 3.0 IMPLEMENTATION The following section provides a description of the planned implementation. 3.1 SITE PREPARATION Existing asphalt and asphalt grindings will be removed from the pilot study area leaving bare ground for implementation. Under the supervision of Sand-Creek Consulting, Inc. (Sand-Creek) 90 individual tree wells will be installed. ET Technologies will drill and backfill boreholes under the supervision of Sand-Creek. Stantec will provide two technicians to aid with installation. An excavator mounted solid-stem auger will be used to advance 12-inch diameter boreholes to a minimum depth of 15 feet bgs up to a maximum completion depth of 20 feet bgs, as soil conditions allow, with the intent of installing the borehole terminus into the confining clay layer beneath the shallow saturated zone (see Appendix B – Figure 4). Borehole spoils will be distributed around each boring and leveled (it is assumed the spoils will not contain VOCs above regulatory limits). The tree wells will be backfilled with a mix of three parts sand to one part yard waste compost. The yard waste compost will be sourced from the Salt Lake Valley Landfill. During backfill, three to ten gallons of water will be added to eliminate bridging and void space in the backfill material. A single one-half inch diameter by 3 to 6 foot long section of Schedule 80 PVC pipe will be installed along the side of each borehole (see Appendix B – Figure 4); final pipe length will correspond with the length of tree cutting placed in each borehole. This drop pipe will be used to provide irrigation water at depth in order to encourage deeper root propagation towards contaminated groundwater instead of root growth near the soil surface. 3.2 TREE PLANTINGS Both cottonwood varieties (Siouxland and fremonti) will be planted as 1 to 3-foot long rooted stock. The deltoides x trichocarpa (DT) varieties will be planted as 2 foot long cuttings, and the deltoides x nigra (DN) varieties will be planted as 5 to 7 foot long cuttings. Each planted tree will be completed with a 3‐foot square of weed‐stop fabric installed around its base. The fabric will be held in place with steel sod staples. Sand-Creek will remove and replant any trees that have not sprouted within three to four weeks after the initial planting. 3.3 IRRIGATION SYSTEM Following planting, LLDPE irrigation lines will be buried in a shallow 2 to 4 inch deep trench along each tree row. As needed, sod staples will be used to anchor the irrigation lines prior to burial by surrounding soil. Appropriately sized drip emitters will be installed on the irrigation lines at each tree location. The discharge volume and number of drip emitters will be determined based on the available water source or irrigation pump. One quarter‐inch diameter drip lines will be used to discharge water from the drip emitters into the previously installed Schedule 80 PVC drop pipes or to the ground surface depending on the planting depth of the tree stock. As the smaller tree stock matures the drip lines will be transferred from surface irrigation to the drop pipes. Each irrigation line will connect to a 1.25‐inch polyethylene pipe (see Appendix A – Figure 5). PHYTOREMEDIATION PILOT STUDY WORK PLAN Former Varian Medical Systems Facility 4 An irrigation header including air relief valve, filter, and flow meter will be installed on the south-central edge of the pilot study area within a treated plywood or plastic box. The upstream and downstream ends of the irrigation header will be fitted with cam‐lock connectors to allow for easy removal for maintenance at the end of the irrigation season. A matching cam‐lock connector will be provided for the water supply or irrigation pump outlet. Irrigation water will be provided by a deep irrigation well located in the southeast corner of the Site. The irrigation system layout is shown in Appendix B – Figure 3 and details of the irrigation system are presented on Appendix B – Figure 5. 3.4 OPERATION AND MAINTENANCE The trees composing the Phytoremediation Pilot Study will require extra care, especially throughout the first two growing seasons. Maintenance will include: mowing; monitoring trees for proper growth, removal of competing species, and pests; and monitoring operation of the irrigation system. The irrigation system will be connected to a timer which will initially be programmed to water the trees twice per night for a period of 45 minutes per watering. The watering schedule may increase or decrease as needed to maintain optimal growth. The intent is that over time the root system penetrates the saturated zone and the trees are self-sustaining and do not need regular watering. The trees will be inspected during weekly operation and maintenance (O&M) events which Suburbia performs for the groundwater extraction and treatment system. 4.0 SCHEDULE Installation of the plantation was completed during the week of April 30, 2018. The planting schedule was chosen in order to ensure that cuttings have a higher success and lower mortality rate. Installation of three monitoring wells as detailed in Section 5, will proceed following UDEQ approval of this work plan. 5.0 PERFORMANCE MONITORING Three groundwater monitoring wells will be installed after tree planting has been completed. The locations of the monitoring wells is shown on Figure 2. The monitoring wells will be installed to 20 feet bgs and will be completed with 2-inch diameter PVC, fifteen feet of 0.01 inch slotted well screen, PVC riser, and a stick-up well completion anchored with an approximate 18-inch diameter concrete well pad. Two soil samples will be collected during the installation of each monitoring well and submitted for analysis of VOCs. During the June or December 2018 semi-annual groundwater monitoring event, baseline groundwater samples will be collected from the three new monitoring wells collocated with tree wells. Performance monitoring will be performed on the new monitoring wells to evaluate diurnal drop in groundwater elevation in the immediate vicinity of the co-located trees. Monitoring wells EW-39R, MW-37, MW-17, PZ-10 and PZ-11 in addition to the three new monitoring wells will be evaluated for changes in water elevation and a reduction in TCE concentrations. Subsequent groundwater samples will be collected annually during the regularly scheduled Spring PHYTOREMEDIATION PILOT STUDY WORK PLAN Former Varian Medical Systems Facility 5 semi-annual sampling events and during the Winter semi-annual events once trees have become established and water levels indicate signs of groundwater containment. 6.0 REPORTING An installation letter report will be prepared and submitted to the UDEQ-DWMRC which summarizes the as-built completion details of the pilot study and the monitoring and maintenance plan approximately 6 weeks after completion of tree planting and performance monitoring well installation. The results of monitoring and maintenance will be reported in semi-annual monitoring and maintenance reports. A final pilot study letter report will be prepared after approximately 1 to 2 years dependent on the rate of tree growth and evidence of TCE attenuation and/or hydraulic containment. The report will include: • Summary of activities after installation; • Descriptions of tree growth, health, and establishment of the rooting zone in the perched zone; • Evaluation of groundwater elevation, TCE concentration trends, and evidence for biodegradation; and • Recommendations for full-scale implementation. 7.0 MAINTENANCE OF SITE MANAGEMENT OBJECTIVES Containment of the VOC Western Plume will continue to be achieved through hydraulic containment of shallow groundwater throughout the Phytoremediation Pilot Study in accordance with the Site Remediation Plan which requires operation of the Western Trench. Pilot study data will be evaluated to assess reliability of hydraulic containment with full-scale phytoremediation implementation. FIGURES MW-02R MW-06MW-10 MW-12 MW-13 MW-20 MW-24 MW-29 MW-32 PZ-05 PZ-07 PZ-08 PZ-09PZ-10 PZ-11 PZ-12 MW-37 MW-38 D-2 D-3 BM Varian MedicalSalt Lake CityFacility D-B MW-15A MW-16 MWD-2 MW-19 SVE-3 SVE-2 SVE-1 SVE-4 West Trench Sump MW-36MW-34 D-C D-D MW-04 MW-35 MW-17 MW-41 MW-31PZ-06 MW-25 MW-26R NorthTrenchSump MW-30 MW-40 MW-33 MW-14 MW-27MW-28PZ-01 PZ-03 MW-44 MW-42 MW-43 MW-05 MW-18 PZ-17 PZ-16 Shimizu Truck Maintenance Building D-A EW-39R D-1 Pioneer Road 1700South µ 0 70 140 Scale in Feet EXPLANATION G (A TE TE !@ #Ç Ditch sample Piezometer SVE well Slurry wall Monitoring well Extraction well Trench sump Extraction trench SlurryWall WestExtractionTrench 26 Apr 2018 Building 3 US Construction Properties Shimizu Property VarexImagingProperty C:\Data\MWH\VARIAN\Fig 1_SiteMap_26Apr2018.mxd Building 2 Building 5 Building 4 Building 1 EnvironmentalTreatmentSystem NorthExtractionTrench EnvironmentalTreatmentSystem DRAWN BY D. Severson Aerial Photography: 8 July 2016 FIGURE 1 SITE MAP PhytoremediationPilot Study Area(SEE FIGURE 2) MW-20 PZ-08 MW-37 MW-38 MWD-2 PZ-17 EW-39R PZ-10 PZ-11 µ 0 20 40 Scale in Feet Aerial Photography: 15 Jun 2017 26 Apr 2018 C:\Data\MWH\VARIAN\Fig 2_Phytoremediation Pilot Study_26Apr2018.mxd DRAWN BY D. Severson nm nm nm nm nm nm nm nm nm nm nm nm nm nm nm nm nm nm nm nm nm nm nm nm nm nm nm nm nm nm nm nm nm nm nm nm nm nm nm nm nm nm nm nm nm nm nm nm nm nm nm nm nm nm nm nm nm nm nm nm nm nm nm nm nm nm nm nm nm nm nm nm nm nm nm nm nm nm nm nm nm nm nm nm nm nm nm nm nm nm PZ-09 MW-17 FIGURE 2 PHYTOREMEDIATION PILOTSTUDY AREA GROUNDWATERMONITORING WELLS Siouxland hybrid cottonwood (all males) OP367 hybrid cottonwood (sterile) 15-029 hybrid cottonwood (sterile) DN21 hybrid cottonwood (sterile) 50-197 hybrid cottonwood (sterile) Western cottonwood (all males) Proposed monitoring well Monitoring well Piezometer Extraction well Slurry wall Extraction trench (A TE #Ç nm nm nm nm nm nm 15' TYP End of 0.710"OD LLDPE lines From watersource 1.25" SDR21 PE #*#* 1.25"flushvalve 1.25" to 0.710"OD LLDPE lineconnections End of 0.710"OD LLDPE lines 15' TYP TE (A MW-45(P)MW-46(P) MW-47(P) APPENDIX A Utah Department of Environmental Quality, Division of Waste Management and Remediation Control, Electronic Correspondence From:Hao Zhu To:Fendler, Thomas Cc:John Buchanan (John.Buchanan@varian.com); McGrath, Angus; Brad Maulding Subject:Re: Varian Phytoremediation Pilot Study Date:Thursday, March 01, 2018 2:31:25 PM Tom, it appears that the research paper supports a pilot test of phytoremediation at the Varexsite. We encourage implementation of innovative technologies that may be cost effective and expedite the long term site management obligations. A work plan for the pilot study shouldconsider the following: 1) A sound and reliable performance monitoring should be designed. 2) The site specific conditions that are not presented in the research paper may vary at theVarex site. 3) Any innovative approaches to be applied the Varex site must not compromise the overallsite management objectives that ensure effective groundwater containment and acceptable risk to all receptors. Given the anticipated implementation schedule, please let me know when you would submit awork plan. Please contact me if you have any questions. Thanks,Hao On Wednesday, February 28, 2018, Fendler, Thomas <Tom.Fendler@stantec.com> wrote: Hao, Thanks for taking time out of your day to discuss this Pilot Test with me. As discussed we would like your feedback on a pilot study to evaluate 1) the effectiveness of Phytoremediation and 2) the most successful poplar tree varieties at the site. For this to be a successful application it is essential for the installation happen by early May in order for the trees to develop roots prior to the onset of high temperatures in the summer. We have already completed a good bit of planning and have a Phytoremediation vender lined up to assist with the project. Attached are a research paper and presentation which describes an approach which is very similar to what we are proposing. I also attached Stantec’s proposal which provides somedetails of the scope and execution for the pilot study. Please get back to us today or tomorrow with any feedback you might have. We are planning to send you a work plan which would provide design plans for the project. Let me know if you’d like additional literature and I can see if our subcontractor has more information. Feel free to call me on my cell phone if you have any questions on this pilot study. Tom Fendler Senior GeologistStantec3995 South 700 East Suite 300, Salt Lake City UT 84107-2540Phone: (801) 743-4843Cell: (801) 230-6646Tom.Fendler@stantec.com The content of this email is the confidential property of Stantec and should not be copied, modified, retransmitted, or used for any purpose except with Stantec's written authorization. If you are not the intended recipient, please delete all copies and notify usimmediately. ü Please consider the environment before printing this email. -- Hao Zhu | Engineer, P.E.801.536.0249 (office) | 801.536.0222 (fax) 195 North 1950 West, Salt Lake City, UT 84116hzhu@utah.gov Disclaimer: Statements made in this e-mail do not constitute the official position of the Director of the Division of Waste Management and Radiation Control. If you desire a statement of the Director's position, please submit a written request to the address below, on paper, including documents relevant to your request. Director, Division of Waste Management and Radiation Control, P.O. Box 144880, Salt Lake City, Utah84114-4880. APPENDIX B Sand-Creek Consulting, Inc. Phytoremediation Pilot Study Design and Planting Plan Sand Creek Consultants, Inc. Page 1 of 3 March 29, 2018 Mr. Tom Fendler Stantec, Inc. 3995 South 700 East, Suite 300 Salt Lake City, UT 84107 Re: Former Varian Facility 1678 Pioneer Road Salt Lake City, Utah Subject: Phytoremediation Pilot Study Design and Planting Plan Dear Mr. Fendler: The following text and enclosures constitute our design document for the plant‐based remediation pilot study at the Former Varian Facility located at 1678 Pioneer Road in Salt Lake City, which is shown on Figure 1. The location of the pilot planting on the parcel is shown on Figure 2. The pilot study will be a trial planting of 6 varieties of hybrid cottonwood trees. The purpose of the pilot study is to determine what varieties will grow best at this location which has somewhat saline groundwater. The pilot will include a sub‐surface drip irrigation system that can provide supplemental water during the first year or two of growth while the trees are establishing root systems down to the capillary fringe. Required Site Preparations Existing asphalt and asphalt grindings will need to be removed from the pilot study planting area. The surface can be gravel and/or mineral soil and should be leveled. Tree Plantings Tree plantings will consist of six varieties of hybrid cottonwoods including one pure eastern cottonwood Populus deltoides, variety Siouxland; one pure western cottonwood P. trichocarpa or fremontii; two varieties of P. deltoides X P. trichocarpa crosses: 15‐029 and 50‐197; and two varieties of P. deltoides X P. nigra crosses: OP367 and DN21. The Siouxland and western cottonwoods will all be males and will not produce cotton. The remaining varieties are sterile species crosses. Each tree variety will be replicated 15 times, with a total of 90 trees planted. Prior to planting, a 12‐inch diameter by 15‐ to 20‐foot deep borehole will be advanced with a solid‐stem auger mounted to an tempexcavator. Attempts will be made to drill boreholes up to 20 feet in depth; however, final boring depths will be determined in the field based upon the capabilities of the operator to reach the target Mr. Tom Fendler/Stantec, Inc. Phytoremediation Pilot Study Design and Planting Plan Salt Lake City, Utah March 2018 Sand Creek Consultants, Inc. Page 2 of 3 boring depths will be determined in the field based upon the capabilities of the operator to reach the target depths and soil conditions such as the ability for the borehole to remain open. Spoil from each boring will be distributed around the borehole and leveled by tillage. Each borehole will be backfilled with a mix of 3 parts sand to 1 part yard waste compost. The yard waste compost will be sourced from the Salt Lake Valley Landfill. During backfilling, 3 to 10 gallons of water will be added to eliminate bridging and void space in the backfill material. A single ½‐inch diameter by 3‐ to 6‐foot long length of Schedule 80 PVC pipe will be installed along the side of each hole, depending on cutting length. This pipe will be used to provide irrigation water at depth. The cottonwoods will be planted as 3‐ to 4‐foot long rooted stock. The deltoides x trichocarpa (DT) varieties will be planted as 2‐foot long cuttings and the deltoides x nigra (DN) varieties planted as 5‐ to 7‐foot long cuttings. All trees will have a 3‐ by 3‐foot square of weed‐stop fabric installed around its base. The fabric will be held with steel sod staples. The proposed planting layout is presented on Figure 3 and planting details are shown on Figure 4. Three to four weeks after the initial tree planting, Sand Creek will remove and replant any trees that have not sprouted. Irrigation System After tree planting is completed, 0.710‐inch OD LLDPE irrigation lines will be laid along each tree row and buried in a shallow 2‐ to 4‐inch deep trench. As needed, sod staples will be used to anchor the irrigation lines prior to burial by local spoil. Appropriately sized drip emitters will be installed on the line at each tree location. The discharge volume and number of drip emitters will be determined based on the available water source or irrigation pump. One‐quarter‐inch diameter drop lines will be used to discharge water from the emitters into the ½‐inch x 3‐ to 6‐foot lengths of Schedule 80 PVC pipe. Each 0.710‐inch irrigation line will connect to a 1.25‐inch polyethylene pipe using a Blazing Saddles 12500 connection. The end of each irrigation line will be closed with a plastic figure‐eight fitting. An irrigation header including air relief valve, filter and flow meter will be installed on the south central edge of the pilot planting within a treated plywood box. The upstream and downstream ends of the irrigation header will be fitted with cam‐lock connectors to allow for easy removal for maintenance and at the end of the irrigation season. A matching cam‐lock connector will be provided for the water supply or irrigation pump outlet. Irrigation water can be provided via a hose from the building or a mobile tank using an electric or gas powered pump. Water supply flow and pressure requirements will be 1.5 gpm at 20 to 40 psi. The irrigation system layout is shown on Figure 3 and details of the irrigation system are presented on Figure 5. Mr. Tom Fendler/Stantec, Inc. Phytoremediation Pilot Study Design and Planting Plan Salt Lake City, Utah March 2018 Sand Creek Consultants, Inc. Page 3 of 3 Operations and Maintenance Living systems require extra care, especially over the first two growing seasons. This includes mowing, monitoring trees for proper growth, competition, and pests, and monitoring the irrigation system for proper operation. Annual start up and shutdown instructions will be provided for the irrigation system. Conclusion Thank you for your time and consideration of this plan. If you have any questions or concerns, please contact me via phone at 715.365.1819 or by email at bart.sexton@sand‐creek.com. Your questions on this matter will receive my prompt response. Sincerely, SAND CREEK CONSULTANTS, INC. Bart Sexton, MS, PSS Project Manager Enclosures: Figures 1 through 5 Via email only DRAWN BY:NRB APPROVED : BTS DATE: MARCH 2018 SCALE: 1"=2000' 20001000 SCALE IN FEET 0 SCALE: DATE: 1"=130' MARCH 2018 PHYTOREMEDIATION TRIAL PLANTING SITE DRAWN BY: NRB APPROVED BY: BTS FORMER VARIAN FACILITY 1678 PIONEER ROAD SALT LAKE CITY, UTAH 13065 SCALE IN FEET 0 LEGEND SCALE: DATE: 1"=20' MARCH 2018 PLANTING LAYOUT DRAWN BY:NRB APPROVED :BTS 2010 SCALE IN FEET 0 DETAIL 1 HYBRID POPLAR DEEP PLANTING DETAIL 3 PLAN VIEW SCALE: DATE: AS NOTED MARCH 2018 PLANTING DETAILS DRAWN BY: NRB APPROVED BY: BTS FORMER VARIAN FACILITY 1678 PIONEER ROAD SALT LAKE CITY, UTAH DETAIL 2 DRIP LINE TO 1.25" 100 PSI CONNECTIONS DETAIL 4 END OF DRIP LINES DETAIL 3 END OF DRIP LINES DETAIL 1 IRRIGATION SYSTEM HEADER SCALE: DATE: NOT TO SCALE MARCH 2018 IRRIGATION DETAILS DRAWN BY:NRB APPROVED :BTS