FULL PACKET_2018-06-19 (INCLUDES 25E EXHIBITS)

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; r. ON -CALL ENGINSERINO BRRVICES WwwrWwwm-0MbnA static water level have remained consistent; and/or the Well begins to liump send and/or gravel pack, or even. displays large amounts of entrained air In the pumped dlschargs� The causes for these observed conditions can. be due to many reasonsi incI40In'q:pump, motor, and/or electrical pir.obithns, resulting In decreased production rates; biological foullino of the perforations and . grovel pack, resulting In plugged cond * Itions, thereby idecreasIng th.0 production rate and spedific capacity and deepen" of the pumping levels, and even loss of pump efficiency; and/or development of holes In the well casing and/or enlargement of the perforationst resulting In the productionof sand. When con8ldeflogwall' rehabilitation, alte-speolfla data from the well in question needs to be evaluated to determine what could be causing . the observed conditions, Therefore, It Is Imperative to Obtain and review avatlable *.data ion both historic anditurrant values for:statlo and pumping water levels; Water quality; specific capacity; well construction records; previous wall rehabilitation WO&, production ratom, and video logs, 01C. OnlVthrough.rovlew of such dsta:by' qualified. hydrogoologIsts Can the potential reason(s) -for the decreases In well I pqrformanoeand the Idohtifloation of rehabilitation steps be defined, It Is understood That the subject of the Santa Ana Water Project Is roporiedas being 30, years old and Is currently producing sand. Because It Is constructed of low carbon stoel,, tho:ossing may be reaching near the end of Its useful 11110. and f unfiet operations may leadto complete failure, e.g., by a potential casing collapse, However, the life of the existing well could be eXtond6deornewhat longer by the Installation of a 1011, stainless-atool' liner casing In the well and this ls.ttie prime recommended course of action that can.now be undertaken on the well, The proj%t can be approached In One Of two ways by the0ty, An Initial approach, and one that Is less efficient, Is to conduct this Initial work as part of a prepared set of Technical Specifications where all rehabilitation options aroincluded. However, a second, and more efficient approach, would be for the City to contract with a well robabill-Jaflon Company to conduct Initial Investigatory operations on the wall to determine the burreht'downhole conditions In the well. This would Include conducting an Initial short-term pumping test to obtain the current, pro-rehablitation specific capacity of the well, This would be Immediately followed by removing the pump and running a down -wolf video survey to determine the observable condition of the Casing and the perforations, and depth of the sand In the well. This would be a preferred approach, because by determining the current Condition of the well, a sot of Technical Specifications can be prepared with the necessary rehabilitation operations already provided. This Is the approach that Tatra Tech Is using on the Well No. 32 Rehabilitatloft Project for the oily, The tasks for this preferred Initial approach would be as follows: I . Following removal of the pump motor, column and bowls from the well, Inspect and rnsasure all apparatus (conducted by the contractor In the field and at the pumping contraotor's shop). 2. Sound the bottom of the casing to determine the current amount (and type) of sediment fill and then ball that sediment from the bottom of the casing; examine the Collected sediments and possibly conduct laboratory analysis, Check carefully for the possible presence of gravel pack and/or formation sand In the belled material. 3, Perform a current video survey of the well to determine the depth to which sand has filled the well; check for possible holes in the casing, and the possible extent of plugging of the perforations. City of $onto Am �9_ T91'RA TIRCH 25E-1 74