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CaliforniaRegional Water Quality Control Board <br /> 4 February 2020 <br /> Page 3 <br /> LOCATION HP 25 / M49C <br /> Proposed sampling location HP125 Is n the frontage road near farmer Ci Flocations CPT-27 and <br /> MP132, Immed "at of the Walnut Avenue extraction wens and approximately downgadient of the <br /> 0A/B/CS well cluster. The groundwater plume i known to exit in the Shallow Auler M these <br /> locatkars, and is being addressed with the current undwaR <br /> n ther Intermediate Broker (M,10CH haveVestment Water. <br /> increased <br /> sed <br /> (with T(£ groundwater" l,2--BCE deeaed at concentations of 110 and 20 Vast, respectively, 20" <br /> sampling ent). Depth-discrete sampling at HP125 will provide Information oeevaluate IItheuY <br /> grouradearter plume has extended aowngretlient of M-1gclto HPRS, and if so, what depth intervagsi <br /> are tied. Conference, a monitoring well (M-s9g will stalled in the Intermediate Zone to so <br /> that er downgramem of M-10CIcan continued to he monitored to tack the arrival of the <br /> plume at this mention. <br /> Field Methods <br /> Haley A Aldrich proposes to advance four borings In the Noah area to the base of lye Intermediate zone, <br /> anticipated to be between OR and 190 feet bgs,for the collection a multiple depth-discrete groundwater <br /> Groundwater samples will be collector from up to five depth intervals, including the upper <br /> Cl Zone and the lower Zone. The investigation methods are described below. <br /> FIELD PREPARATION <br /> Prior othe startof field usual Haley & Aldrich will optima the Site-specific Health and Safety Plan; <br /> obtain soil bon County Enw Department; obtain s <br /> encroachment permits the City of Ripon for any work performed in[ ceppublic To of way; <br /> oordinate accesswth a0mody Owners (Ripon CM1astiam School and Ripon Public school); and contract <br /> with a utility location subcumraaorand a allies subc Aontracer. Haley & mid] will markeach <br /> proposed lmestlgati0n location and nmify Undequound <br /> service Alert at least 48 hours priorto the start <br /> offieldwark. Prior o advancing imertigativet0ol & ea M1 oration will be screenedfor utilities bya <br /> private utility mratorand/Or manually excavated too depth of s feet figs. <br /> DRILLING ANDSAIMPLING METHODS <br /> Each real be advanced mingsonk drilling m&ho&tothe base of the Intermediate zone. sonic <br /> drilling Is expected to he more effective at reachmgthetargems! depth Intervals than CIPTdrilling. Each <br /> fimingwill becontinuously co sod will be lamed by of eomgist rtbes <br /> of a California Professional Geologistand <br /> a general accordance with ASTM International Standard o 4W <br /> (standard Practice for Description and Identification of son, visual-Manual Proeedure). Soil cores will <br /> also be screened fororganicvapors using a phomnnuation dete for. <br /> While advancing each boxing, depth-discrete groundwater samples will be collected by pushing a <br /> Hydropunch style sampling Rol up to 5 feet past the end of thesomc axle, then agraaingthe tooling <br /> p to 4feette exposethescreenn Interval t0 the surroundmgformation. Prior to expointheessayeen, a <br /> "ARCH RICH <br />