Water supply
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St. Johns River Water Supply Impact Study
St. Johns River Water
Supply Impact Study
Studying the St. Johns River
as a potential water supply
The St. Johns River Water Management District is conducting the St. Johns River Water Supply Impact Study to evaluate the potential environmental effects of proposed river water withdrawals on the plants, animals and water resources of the St. Johns River.
A District scientist uses a hydrolab device to measure water quality.
The goal of the study is to provide an objective, comprehensive and scientifically rigorous analysis of the potential environmental effects of river water withdrawals to help guide future decision-making by the District.
The investigation is the most comprehensive study of the middle and lower St. Johns River basins ever undertaken. The study is advancing the science of the river, benefiting the District regarding permit application decisions for river water withdrawals to supplement groundwater supplies, and local governments with whom the District partners on projects to address the river’s water quality issues.
The study will provide a body of advanced science and engineering knowledge, methodologies and analyses to evaluate future permit applications seeking water withdrawals from the river. Its findings will be used to guide the District, as well as the regulated public, including water suppliers and local governments, in making sound policy and permitting decisions.
First phase (December 2007 through September 2008)
During the first phase of the study, District scientists and engineers worked in collaboration with nationally recognized experts. The work of those outside experts involved improving and extending the District’s hydrodynamic models; examining the linkages between biological resources, water levels and flow rates; and identifying the suite of potential environmental effects.
In addition, data deficiencies were identified and new data collection efforts were initiated for larval fish while more intensive sampling was initiated for submersed grass beds, phytoplankton and salinity.
A technical symposium was held in September 2008 to bring together the outside experts and District staff for an exchange of information and ideas. The event was open to the public and broadcast over the Internet.
A District scientist uses a probe to take a water sample in the St. Johns River.
Second phase
(October 2008 to present)
The second phase kicked off in October 2008 with a contract agreement with the prestigious National Research Council (NRC) to conduct a peer review of the District’s project at key intermediate points during the study. The NRC committee has held meetings to discuss the District’s work, which seeks to ensure that the District conducts the highest level of analysis.
Using state-of-the-art models, the study analyzes a range of water withdrawal scenarios that are representative of potential future water withdrawals. The study then categorizes the potential for environmental effects on critical biological communities, species and water resources.
In the second phase of the study, the project team has continued to collect and analyze data while the NRC committee simultaneously conducts its review.
A final report is scheduled to be released in February 2012.
Funding
The District anticipates that it will commit approximately $3.5 million to the project.
Study costs were originally estimated at $2 million, and have increased due to the engagement of the NRC as a peer review panel, hiring more than a dozen outside experts to assist in the project.
Milestones and key dates
- December 2007 — St. Johns River Water Supply Impact Study launched
- September 2008 — District held first technical symposium
- October 2008 — Second phase began; contract between the District and NRC for peer review began
- January 2009 — District released interim phase one report
- August 2009 — NRC issued report on its review of the interim phase one report
- September 2009 — District held second technical symposium
- February 2012 — Final report to be completed


