web site analytic

Pilot Aquifer Storage and Recovery Program

Client: St. Johns River Water Management District

Location: Volusia County, FL

Summary: The St. Johns River Water Management District (SJRWMD) is undertaking a subregional pilot study to investigate aquifer storage and recovery (ASR). The City of DeLand and Volusia County are Cooperators in the SJRWMD’s ASR Demonstration Program, and are seeking to prove the application of aquifer storage and recovery (ASR) technology within the subregional area including these utility service areas. The SJRWMD is funding the majority of the design, permitting and construction costs. The Cooperators will test the effectiveness of ASR systems using potable water from the nearest finished-water distribution lines. After the effectiveness of the ASR wells has been established, the City and County will decide whether to utilize the well system(s) for surface water ASR (from the St. Johns River).

Desktop feasibility studies were conducted by ENTRIX, Inc., which identified an exploratory well site for each of the Cooperators. However, after conducting site specific testing of the lower Floridan Aquifer at the primary locations, favorable conditions for developing ASR projects were not encountered. Therefore, a new search for viable locations for ASR in southwestern Volusia County was conducted. A follow-up investigation resulted in alternate-site exploration program undertaken prior to developing any final plans for a Pilot ASR project.

A detailed exploration and testing program was developed in order to evaluate the hydrogeologic character of the alternative site with regard to implementation of ASR. The work scope and testing program included comprehensive analyses of conditions required for the successful application of ASR. Some elements of the project work scope were contingent upon identifying a zone within the aquifer system that would be appropriate for conducting a pilot test.

Some of the most important factors to evaluate when considering an aquifer zone for storage of water are:

  • Degree of confinement above and below the storage interval.
  • Thickness of the storage interval.
  • Native water quality within the storage interval.
  • Hydraulic conductivity of the storage interval and
  • Flow pattern (matrix vs. fracture).
  • Geochemical nature of the aquifer and its impact on the ASR process.

Portions of the upper Floridan Aquifer appeared to contain water of a suitable quality for ASR. The interval recommended for developing the ASR Pilot projects was between approximately 115 feet and 145 feet NGVD.

The ASR wells were designed to store water within this target interval and Underground Injection Control draft permits were obtained from the Florida Department of Environmental Protection. The major components of the recommended ASR pilot projects are 1) one ASR well; 2) two onsite, aquifer-storage zone monitor wells; 3) a pH adjustment system; 4) a 12-inch diameter pipeline connecting to the Cooperators water supply main; and 5) a disinfection system for the recovered water.