Wellfield Relocation, Expansion, & Monitoring at the Cholla Power Plant

Under an expedited deadline, M&A shifted production to wells that are located on APS property, maintaining continuity for Cholla’s water supply. We also helped to expand this wellfield to develop redundancy and increase reliability. Ongoing work includes monitoring and modeling to support operational decisions at the site.

Overview

M&A has supported APS for more than a decade at the Cholla Power Plant. Early in our involvement, a long-term land lease was terminated, threatening the plant’s water supply because many of its production and monitoring wells were located on this property. M&A worked with APS to replace production wells, develop a new monitoring network, and establish programs for ensuring the reliability of water supply.

Services

M&A provided a range of services to ensure that the plant would maintain continuity for its water supply. In addition to installing replacement wells, we conducted analyses to support land-condemnation negotiations, constructed a monitoring network, and implemented a comprehensive monitoring program. We also developed a groundwater flow model that was used to help assess pumping impacts and optimize wellfield operations.

Groundwater Resource Development

  • Conducted an exploration program that entailed characterizing fracturing and assessing potential yields from the sandstone aquifer to support the siting and design of production wells
  • Deployed downhole explosives in selected boreholes to enhance fracture connectivity and increase yields to more than 3,000 gpm in some wells
  • Designed, installed, and tested 11 new production wells and modified two existing wells
  • Monitored water levels / quality and pumping rates and analyzed data to optimize the pumping distribution across the wellfield
  • Supported an evaluation of the potential for well casings and pumps to deteriorate because of water quality issues, including dissolved gases

Groundwater Modeling

  • Developed a groundwater flow model to simulate drawdown impacts from historical pumping and to identify operational strategies that would minimize the decline of water levels and the migration of poor-quality water