Municipal Wellfield Evaluation & Expansion

M&A evaluated and ranked 11 existing City wells that could potentially be used to augment municipal water supplies. We found a solution that offered the highest production potential, lowest O&M cost, and lowest overall risk. We ultimately developed specifications for four replacement wells and oversaw their drilling, installation, testing and development.

Overview

The City of Glendale’s Oasis Water Treatment Plant was constructed in 2007 to supply its Zone 4 distribution area. Under Phase 1, which was completed in 2007, facilities were constructed to treat about 10 mgd of surface water that is delivered to the plant via the Arizona Canal. Completed in 2011, Phase 2 was implemented to increase plant capacity by 10 mgd and ensure a reliable supply during canal dry-ups and periods of surface water shortage. It required augmenting supplies with groundwater.

Services

M&A served on a multidisciplinary team to develop this groundwater supply.

Groundwater Resource Development

  • Used the results of reconnaissance investigations, downhole video surveys, and various analyses to prioritize wells for further field investigations
  • Identified sensitive well site issues (historic preservation areas, noise, and inconvenience to commercial, residential, and adjacent city service areas) and coordinated mitigation plans
  • Evaluated and ranked City wells that could potentially be used to supply this water; ranking criteria included distance from the treatment plant, registered production capacity, site dimensions, and anticipated configuration and condition
  • Assessed options for using these wells to supply the treatment plant, considering factors such as capacity, capital and O&M costs, risk, logistical issues, and water quality
  • Conducted field investigations at the four most viable wells to assess their physical condition, potential yield, site-specific aquifer properties, and logistical factors

Groundwater Modeling

  • Modeled the potential impacts of pumping on nearby wells

Wellfield Services

  • Designed four deep replacement wells based on the zonal test results, lithologic logging and sieve analysis, and borehole geophysical logs
  • Selected intervals for zonal testing in the pilot borehole, monitored water quality parameters, and collected samples for lab analyses
  • Specified procedures for decommissioning selected old wells; oversaw and approved decommissioning
  • Prepared technical specifications for drilling, constructing, developing, and testing the new supply wells and for well and de minimus discharge permits