Project Summary Sheet

Study Title: A Retrospective and Critical Review of Aquifer Storage and Recovery Sites and Frameworks within the Upper Floridan Aquifer in South Florida
Study Start Date: October 1, 1999 Study End Date: September 30, 2004
Web Sites: sofia.usgs.gov
Location (Subregions, Counties, Park or Refuge): Southern Florida (including and south of Charlotte, Glades, Okeechobee, and St. Lucie Counties)
Funding Source: USGS's Greater Everglades Priority Ecosystems Science (PES) Initiative
Principal Investigator(s): Ronald S. Reese, rsreese@usgs.gov 305.717.5821
Study Personnel: Carlos Alvarez Zarikian at University of Miami RSMAS-MGG
Supporting Organizations: U.S. Army Corp of Engineers and South Florida Water Management District
Associated / Linked Studies: CERP ASR Regional “Preliminary Hydrogeologic Framework” and PES/CERP ASR Coordination Activity

Overview & Objective(s): Aquifer storage and recovery (ASR) has been described as “the storage of water in a suitable aquifer through a well during times when water is available, and recovery of the water from the same well during times when it is needed”. Water can be stored in aquifers with poor water quality. Precedence for ASR in southern Florida has been set by wells constructed at over 30 ASR sites, mostly by local municipalities or counties in coastal areas. The Upper Floridan aquifer is the aquifer of interest to the Comprehensive Everglades Restoration Plan (CERP) and is the aquifer being used or planned to be used at 29 sites. This aquifer is brackish to saline in south Florida, which can have a large impact on the recovery of the fresh or potable water recharged and stored.

The objectives of this study are to: (1) inventory and assess the strengths and weaknesses of available hydrogeologic, hydraulic, hydrochemical, well construction, and cycle test information at existing ASR sites, (2) conduct a critical review of hydrogeology on a site-by-site basis and relate this to existing regional hydrogeology frameworks, (3) identify hydrogeologic, design, and management factors which locally or regionally constrain the efficient storage and recovery of fresh water within the Upper Floridan aquifer, and (4) conduct a comparative analysis of the performance of all ASR sites having adequate data.

Status: This six-year study is divided into two phases. The first phase laid the groundwork for data inventory, review, and analysis, and the second will allow for collection of additional data as it becomes available, expand the delineation of the hydrogeologic framework at each site, and perform a more complete comparative analysis of ASR sites. The study is in the second phase. Data collection and inventory are complete. The report for the second phase is in the process of being written.

Recent Products: A USGS Water-Resources Investigation Reports was published for the first phase of this study. It is “Inventory and review of aquifer storage and recovery in southern Florida”, WRIR 02-4036.

Planned Products: A fact sheet entitled “Inventory and review of aquifer storage and recovery in the Floridan aquifer system in southern Florida” and a Scientific Investigations Report entitled “Updated review of aquifer storage and recovery in the Floridan aquifer system in southern Florida.”

Specific Relevance to Information Needs Identified in DOI's Science Plan in Support of Ecosystem Restoration, Preservation, and Protection in South Florida (DOI's Everglades Science Plan) [See Plan on SOFIA's Web site: http://sofia.usgs.gov/publications/reports/doi-science-plan/]:

Aquifer storage and recovery (ASR) in south Florida is proposed on a large scale in CERP as a cost-effective water-supply alternative that can help meet needs of agricultural, municipal, and recreational users while providing the water critical for Everglades ecosystem restoration. In CERP plans have been made to utilize ASR on an unprecedented scale. Utility-based ASR could also assist in restoration by providing supplemental public-water supplies and thereby reducing the impact of shallow well fields on wetlands. Results of this study will help the managers of the CERP program and utilities in locating, designing, constructing, and cycle testing ASR wells.

This study supports two of the projects listed in the DOI science plan. It supports the (1) Aquifer Storage and Recovery projects as it provides baseline information that could be used in water quality studies [p. 27] and (2) Comprehensive Integrated Water Quality Feasibility Study as its synthesis information could lead to a better understanding of the water quality impact of ASR activities on the natural system [p. 86].

Key Findings:

1. Only 15 of the 30 sites have conducted 3 or more cycles (recharge, storage, and recovery) and only 10 of these have had a potable water recovery efficiency of 30 percent or more for at least one cycle. Out of all 18 sites with cycle test data, five have had recovery of no better than 10 percent per cycle.
2. Factors that can affect recovery of freshwater, such as thickness of the storage zone, transmissivity, and salinity, vary widely between sites.
3. Recovery efficiency performance is maximized when the storage zone is thin and located at the top of the Upper Floridan aquifer, and transmissivity and ambient salinity of the storage zone are moderate (less than 30,000 feet squared per day and 3,000 milligrams per liter of chloride concentration, respectively). The structural setting at a site could also be important because of the potential for updip migration of a recharged freshwater bubble or compromised confinement.