Morro Bay Water Reuse Feasibility Analysis Support

The City of Morro Bay needed to evaluate how best to use reclaimed water as a way to augment its water supply. Photo credit: GSI's Nate Page.

The City of Morro Bay is building a new water reclamation facility (WRF) with the goal of producing the maximum amount of reclaimed water possible to augment the City’s water supply. To help the City assess how best to use this recycled water, GSI provided technical support to evaluate potential alternatives including: 1) recharging into upstream infiltration basins, 2) delivering recycled water to growers in the Morro or Chorro Valleys in exchange for reduced groundwater pumping, 3) injection and recovery at City wells, and 4) injection into a seawater intrusion barrier. GSI conducted groundwater modeling of the basin, which indicated that the indirect potable reuse via injection of advanced treated recycled water into the aquifer was likely to bring the greatest water supply benefit to the City and its residents.

GSI's work involved:

  • A screening-level analysis of recycled water use alternatives
  • A multiple-well aquifer test to characterize the Lower Morro Valley aquifer
  • A technical analysis of the Chorro Valley Groundwater Basin
  • An assessment of the City’s idle desalination intake wells
  • A modeling analysis of the feasibility of injecting and recovering recycled water in the Lower Morro Valley to enhance water supply

This work is being followed in 2019 by additional detailed groundwater modeling, pilot injection well installation and testing, and initiation of long-term groundwater monitoring.


Morro Bay, California


  • Recycled water use alternatives analysis
  • Aquifer testing
  • Desalination intake wells analysis
  • Indirect potable reuse feasibility analysis
  • Groundwater modeling

Groundwater modeling showed that indirect potable reuse via injection of advanced treated recycled water into the aquifer with subsequent recovery at downstream City wells was the alternative that could bring the greatest water supply benefit.

Photo Gallery

Well testing