25I - AGMT FOR REHABILIATION OF WELL NO. 32

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City of Santa Ana We have assumed four (4) borings, one located at the Well #32 site drilled to a depth of 25 -feet, two (2) borings at the bridge crossing each drilled to a depth of 30 -feet and one (1) boring within Memory Lane drilled to a depth of 10 -feet for the proposed pipeline, We have assumed the following: field exploration can be performed during the daylight hours on weekdays, there will be a no charge permit from the City of Santa Ana, identification, handling and treatment of materials that need to be environmentally addressed are beyond the scope of work, we will request the use chalk based paint for USA marking and the removal of USA markings is not included in our scope of work. Tetra Tech will prepare traffic control plans for all geotechnical field work and will be responsible for notifying the Project Manager two (2) weeks in advance of any geotechnical field work being conducted. Traffic control plans will be submitted to the City staff for review, We understand that we will be required to obtain permits and pay all applicable fees for all geotechnical potholing. Backfill and paving will be as required by the Permitting section of the Public Works Agency. The pavement section shall match the existing pavement, section at a minimum Task 4. Well Assessment including Operations and Capacity Tetra Tech will use as -built plans, survey and conduct any necessary field reviews to evaluate the existing well operations and understand the site constraints. We will coordinate all field investigations of the existing well with the City's Project manager. The City shall supply a "down hole" inspection video profiling Well #32. We recommend the City consider performing the following activities for the Well #32 profiling. These activities will provide the information we need in order to provide recommendations for the rehabilitation of the existing well. We recommend the City perform the following: With the pump installed in the well, collect a groundwater sample for bacteria/biofilm speciation analysis by a laboratory to help determine the presence and type of iron -related bacteria, sulfate -reducing bacteria, and/or slime -forming bacteria that may be present in the well. The water samples would be analyzed for their potential to biologically generate and abiotically precipitate various minerals in the well casing and the surrounding gravel pack and the adjoining formation materials under various pumping and non -pumping conditions, Clearly, the groundwater samples must be sent to a laboratory that specializes in such testing and Water Systems Engineering (WSE) laboratory is one such laboratory that can be used for this type of analysis. 2. Conduct a dynamic flowmeter (spinner) survey, to determine the pre -rehabilitation down well flow regime, The City might also want to consider removing the pump and obtaining the following information: When removing the pump motor, column and bowls from the well, inspect and measure all apparatus (both in the field and at the pumping contractor's shop); examine the scale from the pump apparatus and possibly send samples of the scale to WSE for specialized laboratory analysis. 2. Sound the bottom of the casing to determine the amount of sediment fill and then bail that sediment from the bottom of the casing; examine the collected sediments and possibly conduct laboratory analysis (if deemed necessary). 3. Perform a Casing Inspection Thickness Measurement (CITM) survey following removal of the permanent pump. This type of survey allows for the measurement and recording of the current thickness of the walls of the steel well casing, which can be used to compare to the reported thickness of the walls of the installed casing. Thus, this survey can be very 251-20