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The City of Phoenix Water Services Department Water Engineering Division identified 41 of their water production wells as candidate sites for well abandonment and site demolition. These wells had been out of service for many years and the City had plans to release some of the property for sale or utilize the former well sites in some other manner. The wells ranged in size from 8 to 20 inches and from 840 to 1,793 feet deep. During preliminary design meetings with the Arizona Department of Water Resources (ADWR), HSI was requested to participate on a special review committee to develop a Well Abandonment Substantive Policy for future well abandonment activities. After HSI submitted the well abandonment applications for ADWR’s review and approval, the list of well sites was reduced to 27. The remaining well sites were intended to be incorporated into the ADWR groundwater monitoring program. Each of the 27 sites has been abandoned with demolition activities complete, as contracted. The City contracted the services of HSI for coordinating the project, conceptual well abandonment design, permitting and providing technical oversight of all work associated with the well abandonment process. HSI provided oversight and data analysis for video and geophysical logging of the wells to develop a well abandonment design to meet ADWR regulatory requirements. |
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Pouring cement slurry down the wells. |
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Well Rehabilitation and Abandonment |
Well Rehabilitation and Maintenance |
Well Abandonment |
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Evaluation of the efficiency of the Fountain Hills Recharge Facility ASR Wells as well as microbiological analysis of the backflushed water have been monitored periodically to assess the need for well rehabilitation. Well rehabilitations of the ASR wells and a monitor well have been overseen by HSI in 2002, 2003 and 2005. In each case the rehabilitation has been designed based on observations of downhole video logs and microbiological testing, using the appropriate chemicals, dispersal of chemicals, and physical treatment to effectively clean the well casing, gravel pack, and beyond. These treatments have restored both pumping and recharge capacity of the affected ASR wells. HSI has also worked with the Fountain Hills Sanitary District (FHSD) to extend the performance of their ASR wells between well rehabilitations. This includes regular backflushing of each well to help reduce biological or physical buildup in the well screen and gravel pack, in addition to an ASR wellfield management plan to keep each well operating in recovery or injection throughout the year to prevent deterioration that occurs when the wells are allowed to sit unused. Should the wells need to be shut down for an extended period, HSI developed a strategy to maintain the ASR wells during these periods of hibernation, by pre-treating the wells with a chemical and biocidal treatment. |
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Discharge samples collected after chemical treatment, well screen from video log, and barrels of chemical at well site. |
Fountain Hills Recharge Facility |
City of Phoenix, Arizona |
