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R02-183 (2)Task Order No. 18 Engineering Services for the Siting of Floridan Aquifer Supply Wells Associated with the City of Boynton Beach West Water Treatment Plant A. Background The City of Boynton Beach (the CITY) owns and operates a membrane softening water treatment plant (WTP) located at 5469 West Boynton Beach Boulevard in Boynton Beach, Florida. The WTP has a current capacity of 8 million gallons per day (mgd). The Surficial aquifer is the current source of raw water supply for the WTP. The CITY is planning to increase the capacity of the WTP and is considering utilizing the Floridan aquifer to meet at least a portion of the increased water supply needs. One of the factors in deciding whether a Floridan aquifer source of water supply will be utilized for the WTP expansion is the availability of land on which to site up to six (6) supply wells and the estimated cost of constructing the wells and associated infrastructure. The City has requested that CH2M HILL provide engineering and hydrogeologic services to conduct a study to site up to six (6) Floridan aquifer water supply wells and associated infrastructure. The scope of services associated with this project includes conducting an inventory of land ownership of potential properties on which to locate the Floridan aquifer supply wells and associated infrastructure, prepare a conceptual design, and develop an estimate of probable costs for the installation of the subject wells and related infrastructure. The siting of the water supply wells will include the development of a preliminary wellfield layout concept that incorporates features to avoid and minimize environmental and adjoining user hydrologic impacts. The design of the supply wells and associated infrastructure, including raw water transmission pipelines, will be completed in a subsequent phase of the project. B. Scope of Services This scope of services provides for a siting analysis for up to six (6) Floridan aquifer water supply wells and associated infrastructure. An order-of-magnitude cost estimate for the construction of the wells and infrastructure is also included in this scope of services. This project will include the following components: · Conducting a siting analysis to locate appropriate properties on which to construct up to six (6) Floridan aquifer water supply wells to be located within the City's water service area · Developing a preliminary wellfield concept that incorporates features to avoid and minimize environmental and adjacent user hydrologic impacts · Defining preliminary wellfield transmission piping needs and possible routing, including the definition of preliminary sizing and hydraulic criteria DFB~BB FL AO_SUPPLY_SITING.DOC 1 · Establishing preliminary order-of-magnitude estimates of probable cost for construction of the proposed wells and associated raw water transmission infrastructure Task 1 - Supply Well Site Selection Criteria Task 1.1 - Kickoff Meeting and Site Selection Criteria CH2M HILL shall conduct a kickoff meeting with CITY staff to develop criteria and performance measures for selecting the most feasible supply well sites. Criteria may include cost, land use and ownership impacts on other users of the Floridan aquifer, etc. The selection criteria will be divided into two parts: · Screening criteria · Final selection criteria The first set of criteria will be used to screen alternatives that clearly do not meet minimum requirements established by the CITY. The second set of criteria will be used to evaluate well siting alternatives and require that the CITY assign specific level of relative importance to each. This assignment of relative performance or "weighting" is important when analyzing the final set of alternatives and understanding the tradeoffs between alternatives. A matrix of the criteria, along with respective performance measures and relative weights will be developed and used to evaluate the various sites selected for the supply wells. Task 1.2 - Prepare Technical Memorandum A summary of the kickoff meeting, a listing and description of the selection criteria, performance measures and weighting, along with a sample input of the decision model will be presented to the CITY in the form of a Technical Memorandum. Five copies of the draft TM will be submitted to the CITY for review. Upon receiving and incorporating comments from the CITY, five final copies of the TM will be submitted to the CITY as part of the final report deliverable. Task 2 - Siting Analysis Task 2.1 - Obtain Available Maps and GIS Information from the CITY and County Available GIS coverages and electronic maps in and around the CITY's water service area will be obtained from the CITY and appropriate County and public agencies - Planning and Zoning, Depa~iment of Environmental Resources Management, Property Appraiser's and Tax Offices, South Florida Water Management District (SFWMD), etc. Coverages that are expected to be obtained from the CITY and other agencies include: · Major and minor roads, · surface water bodies, · land use, · zoning, · contaminated sites, · property ownership, DFB~BB FL AQ_SUPPLY_SmNG.DOC 2 · existing transmission and distribution pipelines · other data, as required It is expected that some minor manipulation of the above data will be required for compatibility purposes when importing the various maps. Task 2.2 - Overlay GIS Coverages and Produce Composite Maps After each of the above available GIS coverages and maps have been inputted, a composite overlay map of the CITY's water service area will be developed. This map will be used to assist in screening the well locations, possible transmission pipeline routing and will serve as the base map for the remainder of the project. Task 2.3 - Hydrogeologic Desk Top Evaluation CH2M HILL will obtain available information on the hydrogeology of the Boynton Beach area from CH2M HILL's hydrogeologic database, SFWMD, the USGS, and others as needed. This information will be compiled and summarized in a table format, and will be used to evaluate the selected sites against the selection criteria developed in Task 1.1. Task 2.4- Site Alternative Screening Based on the available maps an~ GIS coverages and the local knowledge of the area, a meeting will be held with the CITY to screen alternatives that are suitable for siting the water supply wells and associated infrastructure. Task 2.5 - Develop Well Site Locations Based on the screening analysis and meetings conducted with land owners, potentially feasible locations for the Floridan aquifer water supply wells will be selected. Locations considered will be at or as close to the West WTP as possible and will be mapped on the GIS base map. The number of locations that will be required to accommodate the six (6) Floridan aquifer water supply wells is not yet known since it is possible that each site may allow for the siting of more than one supply well, while others may only accommodate one. Various combinations of potential well site locations will be developed for further evaluation in Task 4. Task 2.6 - Conduct Field Inspection of Proposed Candidate Locations Following the mapping of the possible locations, a field evaluation will be conducted with the CITY to review site-specific constraints that are not shown on the GIS coverages and to verify the proposed locations. Based on these constraints, the alternative sites may be revised or eliminated. The revised site locations will be incorporated into the final GIS base map. Task 2.7 - Wellfield Layout Concept A preliminary wellfield layout concept will be developed to maximize potential production from the supply wells while minimizing impacts to adjacent users of the Floridan aquifer, as well as minimizing interference between the proposed water supply wells. Raw water transmission pipeline routing will also be included in the wellfield layout concept and will be included in the Technical Memorandum described below. DF8~88 FL AQ_SUPPLY_SITING1 3 Task 2.8- Prepare Technical Memorandum A summary of the Alternatives Screening, the field evaluation, and a description and printout of the firtal alternative site locations will be presented to the CITY in a Technical Memorandum. Several tasks associated with land and easement acquisition will be conducted independently by the CITY and information obtained from this separate effort will be incorporated in the Technical Memorandum. Five copies of the draft TM will be submitted to the CITY for review. Upon receiving and incorporating comments from the CITY, five final copies of the TM will be submitted to the CITY as part of the final report deliverable. City-Assigned Tasks As part of Task 2, the C1TY will contract with others to conduct analysis of probable costs associated with land and easement acquisition and will meet with landowners to assess their willir~gness to sell or allow access by the CITY. Perform a Land Acquisition Cost Analysis The CITY will conduct its own cost analysis for the locations identified in Task 2.6, above. The cost analysis will include an estimate of probable cost for the acquisition of the properties identified. Meeting with Land Owners The CITY will conduct a meeting with landowners to determine if owners of potential well sites will consider selling properties of interest or allow easement access to such properties. Task 3 - Opinion of Probable Cost Task 3.1 - Develop Opinion of Probable Cost Develop a planning level opinion of probable cost (+/-30%) for each of the principal elements of the project including development of the supply well site(s), new wells, well pumps, well head facilities, wellfield collector piping network, and access roadway, or mitigation costs (if required). The CITY will provide costs for purchase of the land or acquisition of easements, but will be included in the total opinion of cost included in the Technical Memorandum below. Task 3.2- Prepare Technical Memorandum Prepare a draft Technical Memorandum for the CITY for review and comment, which summarizes the probable construction cost estimates. Five copies of the draft TM will be submitted to the CITY for review. Upon receiving and incorporating comments from the CITY, five final copies of the TM will be submitted to the CITY as part of the final report deliverable. DFB~EB FL AQ_SUPPLY_SITtNG1 4 presented to the CITY and discussed to decide on the most feasible site for the siting of the Floridan aquifer wells. Task 4.2 - Prepare Technical Uemorandum Following the meeting with the CITY, the most feasible alternative will have been selected and Technical Memorandum will be prepared summarizing the decision model results, the discussions with the CITY and the final siting of the six (6) Floridan aquifer water supply wells and associated raw water transmission pipeline routing. Five copies of the draft TM will be submitted to the CITY for review. Upon receiving and incorporating comments from the CITY, five final copies of the TM will be submitted to the CITY as part of the final report deliverable. Task 5 - Groundwater Uodeling - Optional Following completion of the siting analysis of the Floridan aquifer water supply wells, the CITY may wish to proceed with the modeling of these well sites to determine the potential impacts of groundwater withdrawals from these wells. Therefore, this task addresses the work required to set up and conduct groundwater flow modeling to assess the potential impacts from these withdrawals. Task 5.1 - Set Up Groundwater Flow Uodel Utilizing data gathered as part of the previous tasks with develop and set up a groundwater flow model of the Floridan aquifer utilizing the computer code WinFlow (ESI, 2000). WinFlow contains several 2-dimensional analytical models capable of simulating steady- state and transient flow. Model development will include the selection of appropriate hydraulic properties for the Floridan aquifer and the placement of proposed Floridan aquifer well sites. Adjacent Floridan aquifer wells in the vicinity of the study area will be included in the model domain. Task 5.2 - Predictive Simulations CH2M HILL will meet with the CITY and present suggested predictive simulations and discuss with the CITY which ones appear to be the most likely based on the CITY's understanding of future conditions related to water supply and treatment. The predictive simulations will be run to steady state conditions and consider various combinations of wells and pumping rates. Upon agreeing to up to five (5) predictive simulations, CH2M HILL will proceed with the predictive modeling and will prepare representative resultant water level maps of the five simulations. Task 5.3 - Ueeting and Technical Uemorandum CH2M HILL will meet with the CITY to present the results of the predictive simulations. Following discussion and input from the CITY, CH2M HILL will develop a Technical Memorandum that will describe the set up of the model and the results of the predictive simulations, along with conclusions and recommendations. DFB~BB FL AQ_SUPPLY_SITING.DOC 5 Five copies of the draft TM will be submitted to the CITY for review. Upon receiving and incorporating comments from the CITY, five final copies of the TM will be submitted to the CITY as part of .the final report deliverable. C. Final Deliverables Each task will include a deliverable that will be submitted separately to the CITY for review and comment. Following completion of the project, CH2M HILL will compile all of the final deliverables into a tabbed three-ring notebook for the CITY's file and subsequent reference. Five copies will be delivered to the CITY. O. Assumptions · Properties within the CITY's service area will be the primary focus for siting of the supply wells, however, areas adjacent to the service area will also be considered. · Only available electronic GIS maps will be used to develop the base map and conduct the initial screening analysis. No new GIS layers will be developed. · Only conceptual drawings of typical well diagrams, raw water transmission piping layouts and identification of possible areas requiring easements or property acquisition will be developed. No designs will be developed as part of this Task Order. · CITY will be responsible for providing GIS coverages and other maps that are available from the CITY in electronic format to CH2M HILL. CH2M HILL will be responsible for obtaining other available GIS coverages from the County and other public sources. · CITY will be responsible for conducting the necessary land and easement acquisition analysis and setting up and conducting meetings with individual landowners. CH2M HILL will not be involved in these meetings with landowners. · The groundwater modeling conducted in Task 5 will be set up so that the model can be used for subsequent Water Use Permitting purposes in the event the CITY elects to proceed forward with the design and construction of Floridan aquifer water supply wells. However, per the South Florida Water Management District (SFWMD) guidelines, this would be considered a Type I model and would provide a gross approximation of potential impacts of the proposed groundwater withdrawals. If during the permitting process, conditions warrant that more sophisticated modeling is required, and the data supports it, a separate Type II groundwater flow model such as MODFLOW would have to be developed and utilized. E. Contract Reference This Task Order shall be performed under the terms and conditions described within the Agreement for General Engineering Consulting Services dated October 4, 2000, between the City of Boynton Beach and CH2M HILL, Inc. F. Compensation Compensation by the CITY to the CONSULTANT for services provided in this Task Order will be a not-to-exceed basis in accordance with the above mentioned Agreement. The OFB~B FL AQ_SUPPLY_SITING.DOC compensation for the services described in Task 1 - 5 of this Task Order is estimated at $76,279 as shown below. Work completed by the CONSULTANT will be invoiced monthly on a labor and expenses basis per the above agreement. Task Description Labor Labor Cost Expense Cost Totals Hours Task I - Site Selection Criteria 132 $14,107 $1,361 $15,468 Task 2 - Siting Analysis 224 $20,250 $2,678 $22,928 Task 3 - Opinion of Cost 56 $6,310 $609 $6,919 Task 4 - Final Well Site Alternatives 144 $13,081 $1,853 $14,934 Analysis Task 5 - Groundwater Modeling - 156 $14,469 $1,561 $16,030 OPTIONAL Grand Totals 712 $68,217 $8,062 $76,279 G. Schedule The CONSULTANT will commence services upon receipt of written authorization and will complete the work according to the table below. Task Description Weeks from Written Notice to Proceed Task 1 - Site Selection Criteda 3 Task 2- Siting Analysis 8 Task 3- Wellfield Design Concept 12 Task 4 - Opinion of Cost 14 Task 5 -Groundwater Modeling - OPTIONAL 18 DFB~BB FL AQ_SUPPLY_SmNG.DOC 7 APPROVED BY: CITY OF BOYNTON BEACH, FLORIDA By: /Mayor ~er~ld Br~'[mng Dated this rtl day of ~ 2002. SUBMITTED BY: CH2M HILL, INC. ~,~. ,~ Vic~Pf'esident, Area Manager Dated this [-~--day of ,2002. APPROVED AS T~ FORM: CITY ATTO 8 DFB~B FL AQ_SUPPLY_SITING.BOC