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HomeMy WebLinkAbout017SUBSURFACE GROUP LLC 11220 Fieldstone Lane N.E, Bainbridge Island, Washington 98110 Tel: (206) 778-8074 Fax: (206) 780-5669 MEMORANDUM To: Tom McDonald From: Scott Bender CC: Craig Peck, Garth Mann Date: February 22, 2010 RE: REVISED P'LEASAN'T HARBOR GROUNDWATER MONITORING PLAN This memorandum presents the groundwater monitoring plan to be used during construction and operation of the Pleasant Harbor Golf and Marina Resort. The plan is based on several meetings and discussions with the Department of Ecology and Paefic Groundwater Group, Groundwater monitoring will be perCorined to document water quality and drawdown conditions related to the development, Figure 1 presents a map of the existing and proposed groundwater monitoring instrumentation. Two additional monitoring wells will be insatlled, labeled MW -7 and MW -8 as shown on the attached map., These will be standard 2 -inch diameter monitoring wells completed to a minimum of 10 feet below the water table, The existing monitoring wells are labeled on the map MW -2, MW -4, and MW -5. Wells labeled VWP-I, VWF-3, and VWP-F were geotechnical borings with vibrating wire piezometers installed in them to measure groundwater pressures. The highest groundwater demand at the site will be during site development prior to the construction of the central pond. About one month before construction rend during this period dataloggers will be connected to all of the wells at (lie site, The program will collect rneasureiltients on groundwater pressure and fluid conductivity (which can be correlated to salinity). Dataloggers that record grOLllldwater pressure will be installed at VWP-1, VWP-3, MW -5, and VW -6. Dataloggers that measure both groundwater pressure and fluid conductivity (which can be correlated to salinity) will be installed at MW -2, MW -4, MW -7, and MW -8, These ul,its will record groundwater measurements on a 0,5 hour basis, The datfduggers will be downloaded every two months during the construction season estimated from April 1 to November 1, and every three months in the non -construction period, estimated November 1 to April 1 when there will be minimal well use. During cQnstrLlction, water quality samples Will be collected from dle two supply wells and N,[W-4, MW -7, and MW -8 if ars anornalous conductivity trend is observed, 'The samples will be sent to a water quality laboratory for analysis ofchlorlde and Waves, SUBSURFACE GROUP, LLC SGO601-03 Memorandum to Statesman Corporation February 22, 2010 Page 2 After construction is completed and the Occupancy OC the resort units commences, all of the dataloggers will be downloaded quarterly, Water quality santples will be collected from the supply wells quarterly. This program will be continued for five years or until the resort has achieved M11 build-otit, whichever is longer; at which tune the monitoring plan will be adjusted based on the results of the program. The data will be transmitted to Ecology for their review, W Pleasant Harbor will perform a minimum 72-11our aquifer test at each new water supply well installed for the project. During testing the wells will be sanlapled for electrical conductivity and chloride concentrations, Pleasant Harbor will use its best efforts to sample a miniMLIM of two coastal domestic wells for electrical conductivity and chloride concentrations twice; a year in April and August. Sampling will be dependent upon obtaining the permission, cooperation and availability of the owner of the domestic well. Ecology has identified four potential candidates; Pleasant Harbor will prioritize these wells, and will seek others if the listed wells are not available. For consistency, Pleasant Harbor will attempt to establish a long-term relationship with those weal I owners, SUBSURFACE GROUP, LLC SG0601-03 418, 19 PO .,-- -- '0 1 � Tj 60 X41, 42 211. 15 I V ItNIVed* ITJ 24,29, 10 ' 1 313,40. 22, 44: 45 Pr(pposcri htt %Vcll hicoli(14 I 1001) At (It YJ Notes: 1) Well locations are approximate. Domestic well locations Monitoring Well Location (MW - monitoring well; VWP = vibrating wire piezometer typically to nearest quarter quarter unless better known. 2) See Appendix for well logs It Water Supply Well Location Subsurface Group, Pleasant Harbor Marina and Golf Resor i Domestic Well and Project Number S00601.03 Groundwater Impact Evaluation Monitoring Well LLC Statesman Corporation Locations Figure I