Okaloosa County BOCC — May 6, 2014 — HDR_TaskOrder49 — reading text

TASK ORDER AUTHORIZATION CONTRACT NUMBER: CO6-1346-PW2-118 CONTRACT # C06-1346-PW TASK ORDER #: 4 HDR ENGINEERING CONSULTING ENGINEERING SERVICES EXPIRES: 09/30/2013 OFFERED BY CONSULTANT: HDR Engineering, Inc. FIRM’S NAME Bradford M. Stone REPRESENTATIVE’S PRINTED NAME January 20, 2011 SIGNATURE | Vice President DATE TITLE RECOMMEND FOR APPROVAL APPROVED BY OKALOOSA COUNTY (Per Pui ing Policy) yA SIG pa SIGNATRE 4 Wi, Yon bs BLC TITLE TITLE BOM ZL ay / DATE DATE RECEIVED | FEB 23 201 BY: | ONE.COMPANY || Many Solutions SCOPE OF WORK OKALOOSA COUNTY - NICEVILLE LANDFILL PROFESSIONAL ENVIRONMENTAL SERVICES WELL INSTALLATION January 6, 2011 INTRODUCTION Okaloosa County is proactively managing groundwater and routine environmental compliance issues at its closed landfills. This proposal for environmental services is intended to retain Okaloosa County in a proactive position as it relates to environmental compliance at the Niceville Landfill. As required by the Countys solid waste permit (permit No. 0078402-001-SF) water quality is tested on a semiannual basis at the Niceville Landfill. The results have indicated elevated levels of iron and several other compounds in the groundwater and surface water at the Niceville Landfill. To address these detections, Okaloosa County is conducting an evaluation of remedial technologies including conduct of pilot tests. Previous investigations have largely determined the nature and extent of these impacts. However, along the western portion of the site, additional delineation is now required to delineate the horizontal extent of iron and arsenic levels in groundwater. Installation of additional wells was requested by the FDEP in a letter dated July 16, 2010. Detections of compounds at levels above Primary and Secondary Drinking Water Standards at groundwater monitor wells (MW-23, MW-24 and MW-32) located further west of the landfill prompted the FDEP to request the installation of additional wells downgradient of these wells. These wells are located west of the landfill between the landfill and Turkey Creek in a heavily forested area. During the most recent sampling event: at MW-23 iron was above the Secondary Drinking Water Standard; at MW-24 concentrations of arsenic, benzene and cis- 1,2 Dichloroethene were above Primary Drinking Water Standards and iron was above the Secondary Drinking Water Standard; and at well MW-32, the Iron concentration was above the Secondary Drinking Water Standard. Since concentrations persist above the Primary and Secondary Drinking Water Standards, the FDEP will continue to request that the County install additional wells downgradient of these affected wells to determine the horizontal extent of the groundwater impact. Based on the analytical data we recommend the installation of a total of two wells (southwest of MW-23, and west of MW-24), to determine the extent of these impacts. Depending upon testing results additional wells may be necessary. Additionally we note that an additional well west of MW-32 may at some point be necessary. The first step in implementation is HOR Engineering, Inc. 206 W Forsyth Street Phone: (904) 598-8900 Suite 800 Fax: (904) 598-8988 Jacksonvitle, FL 32202-4321 wena. Adrinc. com ONE. COMPANY | Many Solutions obtaining approval from Eglin and submitting a brief work plan to the DEP. After well installation HDR will prepare a construction documentation report for submission to the FDEP. After installation and sampling FDEP may ultimately require these wells to be added to the groundwater monitoring program. SCOPE OF WORK Based on the request from the FDEP, Okaloosa County has requested HDR install additional wells. This proposal provides a description of the services to be provided by HDR. Task 1; Installation of Groundwater Monitoring Wells In a recent letter DEP requested installation of an additional groundwater wells to further delineate the horizontal extents of groundwater impacts. This task presents a scope of work to install these wells. Task la Work Plan We will walk the site and identify potential drilling locations. Based on this information we will generate a simple map and assist the County in making a request to Eglin to install wells and prepare a work plan for submission to FDEP which describes where these wells are anticipated to be installed. A total of two wells are proposed to be installed each approximately 300-500 feet downgradient of MW-23 and MW-24. Wells will be installed in general accordance with the guidelines presented in Attachment 3 of the facilitys permit. The work plan will include a site map with the location of the proposed wells identified. Upon FDEP concurrence field activities can commence. We have assumed we will review the proposed locations with County on site, and County staff will create an access trail to each of these drilling locations. We have budgeted a maximum of % day onsite to locate the drilling access trails. Prior to drilling we will obtain well construction permits from the Northwest Florida Water Management District. We have assumed County personnel will review and approve the drilling locations, and provide land clearing and trail construction to provide access to these well locations prior to installation. Task 1b Well Installation The shallow monitoring wells will be installed using hollow stem auger (HSA) drilling techniques. Soils will be visually/manually classified by the on-site geoscientist following the Unified Soil Classification System (USCS) and recorded on field logs. The borings will be advanced to a depth of approximately 15 to 20 feet below the water table so that the top of the well screen will be at approximately 5 to 10 feet below the top of the water table, consistent with the 2 HDR Engineering, inc. ONE'COMPANY | Many Solutions» Northwest District of FDEP preferences. This depth will allow the screened interval of the newly installed well to be fully submerged. As specified in the permit, during drilling, a soil sample will be collected for grain size sieve analysis within the interval intended to be screened. Upon reaching terminal depth, the well will be constructed of 2-inch diameter, Schedule 40, flush-threaded polyvinyl chloride (PVC) riser and screen. The screen will consist of a 10-foot section of machine-slotted 0.010-inch slot screen. The sand pack will be sized consistent with other wells at the site and placed to approximately 2 feet above the top of the screen. The filter pack will be emplaced into the annular space between the well and the borehole. An approximately 2- foot thick bentonite seal will be emplaced above the filter pack. The bentonite will be installed between the borehole wall and PVC well pipe and then hydrated. The remaining annular space will be tremie backfilled with Portland Type [ cement (with approximately 5% bentonite added) to the ground surface. ~ A locking metal protective casing will be installed around the well and a concrete pad will be constructed around the protective casing to complete the well. The pad will be gently sloped to direct run-off from the well. A weep hole will be constructed in the well riser to allow water table equilibration and to allow for ventilation and drainage of moisture and rainwater in the protective steel casing. The weep hole in the protective steel casing will be at a lower elevation than the vent hole in the PVC well riser. Coarse-grained silica aggregate will be placed in the annular space between the PVC monitoring well and the protective steel casing. We have assumed that up to 2 bollards will be installed around each well for protection if necessary. Prior to drilling, the drilling equipment will be steam cleaned to reduce the potential for cross-contamination. All downhole equipment will be cleaned using high-pressure steam. The water used for equipment wash, as well as drilling and well construction activities, will be obtained from an on-site potable water source. We have assumed that investigative derived waste (DW), including drilling fluids, soil cuttings, and decontamination water will be not be containerized but will be spread near the well. The wells will be developed upon completion; we have assumed a maximum of 6 hours total for development. We have assumed that a dedicated pump will not be installed in these weils. Purge water will be discharged within the Zone of Discharge. Upon completion, the well will be required to be surveyed. We have assumed that County personnel will survey each well to obtain top-of-casing, ground surface elevation as well as northing and easting (and latitude and longitude as required by Rule 62-701.510(3) (d) 1, F.A.C.). 3 HDR Engineering, Inc. ONE COMPANY (Many Solutions» Task Ie Sampling and Analysis Upon installation and development each well will be sampled. A field technician will sample each weli and submit the samples for laboratory analysis. The analytical suite will consist of permit required compounds. We have assumed the well will be sampled twice during 2011 with the second sampling event anticipated to occur concurrent with the 2"! 2011 semiannual sampling event. Task 1d Reporting A well construction documentation report will be prepared upon receipt of survey data. The report will include a description of installation methodology, lithologic logs, "as-installed" diagrams and a summary of well development. A monitor well completion report form will be completed for each well. This report will include items detailed in Attachment 3 of the permit. Additionally the well construction summary table summarizing all well constructions at the site will be updated with these new wells. We have assumed this report will be included as an attachment to a semiannual assessment monitoring report. FEE ESTIMATE HDR will conduct this work on a Time and Materials basis based on work described herein. Subcontract costs (Driller, lab and geotechnical lab) will be billed in accordance with our contract. These fees do not include fees for any surveying. The estimated cost, $24,049.60 will not be exceeded without prior approval from Okaloosa County. If actual activities change significantly based on progression of the project and its associated data, we will notify the County. ASSUMPTIONS Key assumptions in preparing this proposal include: e The County will provide land clearing and provide an access trail suitable for a 4-wheel drive drill rig to access the drilling locations. e We have not included time for a separate meeting with Eglin officials. @ We have assumed the total footage drilled will be less than 90 feet. e Field activities can be completed in less than 4 consecutive working days. e The County will provide access to the site including any necessary access letters that may be required. e This scope does not include surveying. e Samples from the new wells will be analyzed twice for the permit required parameters. « This scope does not include meeting with regulatory agencies. « The fee estimate excludes wetland delineation. e The County will be responsible for the installation of signage identifying the monitoring wells. 4 HBR Engineering, Inc. ONE COMPANY | Many. Solutions» SCHEDULE The people most involved in this. project will be Brad Stone, PE, John Locklear, PG, John Catches, PG (Sr. Geologist), and Handi Wang (scientist). The project team will be supported on an as-needed basis by other engineers, scientists and technical resources within the HDR organization. The activities described herein can commence immediately upon Notice to Proceed from Okaloosa County. HDR Engineering, inc. JWR ACTIVITLES/SALARIES FEE COMPUTATIONS Projeet: Niceville Client: ‘Okaloosa Cauniy Prepared By: HDR Engineering, in. Date Teton “ACTIVITY Project Prinsipal Sc Project Manager] Sr. ny Scientist [SrProfléngincer Proj Bngince Se SrCADD [Financial Analyst Moxhows_|__Labor — [Dineet sp [Subeantsnetor Total Brad Stone Pit