Investigations & Permitting for the Liberty Aquifer Replenishment Facility

M&A overcame the challenges associated with designing and permitting this facility through close coordination with regulators and stakeholders. Currently in the final design stage, the LARF is expected to recharge at least 78B gallons of water and store up to 6,000 AF/yr of Class A+ treated municipal effluent in an area of extensive historical groundwater depletion.

OVERVIEW

The LARF is owned and operated by Liberty Utilities, with the CAP (through its replenishment arm, CAGRD) providing funding in exchange for a 100-year water supply to help meet its replenishment obligations. The source of effluent is Liberty’s Palm Valley Water Reclamation Facility (WRF).

The permitting process presented considerable challenges because the areas surrounding the site featured other recharge facilities, sensitive land uses, and potential contaminant sources — which could potentially cause unreasonable harm. We needed to project groundwater level rise and thoroughly address issues associated with the Buckeye waterlogged area, Glendale Landfill, sand and gravel pits, existing recharge facilities, known environmental sites, and Luke Air Force Base, among others.

SERVICES

M&A provided a range of hydrogeologic services to select an optimal location for the project, investigate the selected site’s recharge feasibility, and support the facility’s design.

Managed Aquifer Recharge

  • Evaluated hydrogeologic data, land use / ownership and constraints, infrastructure needs and costs, and other information to identify potential recharge sites within a 60-square mile area
  • Estimated sustainable recharge rates based on the lithologic conditions and infiltration capacity of near-surface soils and the vadose zone
  • Evaluated sensitive land uses and potential contaminant sources within the projected Area of Impact (AOI) and completed an unreasonable harm assessment that included developing a bird-strike mitigation plan with Luke Air Force Base
  • Prepared a conceptual recharge basin layout and worked closely with the clients and an engineering consultant to design the recharge facility

Groundwater Modeling

  • Modified ADWR’s Salt River Valley MODFLOW model to project groundwater level rise under the proposed recharge volumes from the LARF and other facilities in the region

Permitting & Compliance

  • Addressed permitting requirements for characterizing effluent discharge, identifying points of compliance, modeling the discharge impact area, designing the facility, and a preparing closure plan
  • Prepared permit applications and supporting documentation
  • Interfaced extensively with state regulators to negotiate permit conditions and address the potential for modified aquifer water quality limits