Minimum flow gets reevaluated

May 2018 – As the City of Tampa grew, and more and more water was withdrawn from the middle river above the City of Tampa Dam, the lower river’s fresh water flow was reduced. This choked the lower river, robbing it of its necessary freshwater estuarine nature to the detriment of fish and wildlife. River advocates, including the River Board and Friends of the River, began a campaign to revive the health of the lower river by bringing back its freshwater flows.

In December 1999, the Southwest Florida Water Management District (SWFWMD) mandated a 10 cubic feet per second (cfs) minimum freshwater flow to resuscitate the lower Hillsborough River below the Tampa dam. River advocates argued this standard was merely a temporary stay of execution based on political expediency and not scientific evidence. In 2006, after an intensive five-year study, SWFWMD released its recommendation for a revised minimum flow of 20 cfs, or 13 million gallons per day, double the first standard. Specifically, 20 cfs for months July to March and 24 cfs for months April – June.

The minimum flow rule designates evaluations of effectiveness in five-year intervals (2013, 2018, 2023). The 2018 evaluation of Minimum Flows and recovery strategy for Lower Hillsborough River is currently underway by the Southwest Florida Water Management District (SWFWMD).

Friends of the River met with SWFWMD on January 11, 2016 to coordinate on the 2018 evaluation. After considering Friends of the River’s comments, SWFWMD agreed to evaluate the 25% loss factor (part of the minimum flow calculation), and that the reevaluation will include both the recovery strategy and the minimum flow. SWFWMD also assured that there will be public participation in the review process. The River Board will monitor SWFWMD’s reevaluation effort and provide comments and recommendations as necessary.

Florida law mandates that water management districts protect state water resources from “significant harm” by establishing minimum flows and levels (MFLs) for streams and rivers within their boundaries. Section 373.042 of the Florida Statutes defines the minimum flow for a surface water as “the limit at which further withdrawals would be significantly harmful to water resources or the ecology of the area.”


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