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Two studies conclude that a desal plant and diversions of freshwater would have an insignificant effect on salinity.
By JEAN HELLER
© St. Petersburg Times, published October 31, 2000
TAMPA -- Two new studies released Monday conclude that two controversial projects to bring new drinking water to a thirsty region would have no significant negative impact on the environmental well-being of Tampa Bay.
The projects are the seawater desalination plant planned for the Big Bend area of southern Hillsborough County, and a system to divert high water from the Hillsborough and Alafia rivers and the Tampa Bypass Canal to stock a new regional reservoir.
Scientists said Monday the impacts would be negligible. Even in a worst-case scenario, the combined impacts of pulling freshwater out while pumping salt in would shift the salinity of Tampa Bay far less than it is shifted naturally by seasonal changes in the weather, they said.
It is unlikely that the findings of "no significant impact" will assuage residents of southern Hillsborough County who have been fighting the two projects for months. But the studies fill in holes in the body of ecological knowledge about the projects that led to some of the criticism.
The salinity study was designed to measure the cumulative impacts on the bay of the desal plant and the freshwater diversions from rivers that feed the bay.
"The model, which is based on two years of data, indicates there is no long-term accumulation of salt in the bay due to the cumulative effects of desalination and the (river skimming) projects," said a 1,000-page report paid for by the desalination contractor, S&W Water, and prepared for the state Department of Environmental Protection, which will have to issue permits for the project.
"There is an increase in salinity (1.3 parts per thousand) at the point of discharge for the desalination plant, which is well within the normal changes of salinity throughout the year," the study concluded. "Adjacent to the concentrate discharge, the salinity increase dissipates rapidly to normal levels."
Dr. Mark Luther, the professor of marine science at the University of South Florida who conducted the study, was more specific.
"One-quarter to one-half mile away from the discharge point, the increase in salinity is so small it can't be measured," Luther said at a news conference Monday.
Within the tidal reaches of the rivers and the canal, there will be additional salinity, but also within the normal range of the seasons, Luther added.
A study of biological impacts of freshwater diversions from the rivers and McKay Bay, done for Tampa Bay Water, the region's largest water utility, found that salinity fluctuations in the bay would extend to the tributaries, but the changes would be small and not persistent.
"Even the largest salination changes will not create an environment that plants or animals will find hostile," said Anthony Janicki, president of Janicki Environmental Inc., which conducted the study.
While the $500,000 cost of the Luther study was paid for by S&W Water, DEP determined what was to be studied and how. S&W Water was required to produce the study as part of the permitting process.
The Janicki study developed a system for monitoring the Hillsborough, Alafia and Lower Palm rivers and McKay Bay at the top of Hillsborough Bay to detect changes in flow, water levels, salinity, impacts on bottom-dwelling animals and plants, fish, and plankton at a cost to Tampa Bay Water of $215,000.
Using the monitoring system will cost $1-million a year.
J.B. Canterberry, the head of Save Our Bays and Canals (SOBAC), a citizens group opposing the desal and surface water projects, did not return phone calls Monday.
Hillsborough Commissioner Chris Hart, who sits on the TBW board, said he was unaware of what the studies concluded, and questioned the wisdom of Tampa Bay Water holding a news conference to make the results public before informing members of its own board.
"If Tampa Bay Water released this, you'd think the very first people they would include were the board members," Hart said. "I think a news conference at this point in the process is not good policy and poor political judgment."
Hart declined to comment on the results of the studies because he hadn't seen them.
"I didn't know they were out there until right now," he said.
Michelle Klase, spokeswoman for Tampa Bay Water, said there is an item on the agenda for the agency's November meeting to brief the board on the studies.
"The Hillsborough water staff has had the (Luther) report for some time," Klase said. "It was sent to them by DEP so they could comment."
Asked if anyone had told board members, Klase said, "Not that I know of."