Alafia River Minimum Flows and Levels - Southwest Florida Water ...

5.6.2 Prescribed Flow Reduction for Lithia Springs Major –
Recreational Use Assessment Results
Based on Department of Health "bathing load" criteria, a flow of 218,000 gallons
per day, or ~0.3 cfs, is necessary to support use of the Lithia Springs Major as a
"bathing place" for the maximum number of individuals (436) that should be in
the pool at any one time. Surveys conducted by District staff for several days in
July 2003, indicate that an average of 16% of the park visitors who entered the
park actually swam in the spring pool, although on one day, the percentage of
park visitors utilizing the pool was 30%. Assuming that 16% of the 2,570
individuals visiting the park on the single busiest day between June 2001 and
June 2003 entered the pool, the minimum necessary spring flow needed to
support this use in accordance with state standards would be 205,500 gallons
per day, or ~0.3 cfs. Assuming that 30% of the park visitors chose to swim on
that day, a minimum discharge of 385,500 million gallons of water per day, or
~0.5 cfs would be required. The minimum flow necessary to support the
traditional and long-standing recreational use of the spring as a bathing place is
therefore apparently less than 1 cfs. This information was identified as a
possible limiting factor for consideration in the development of minimum flows
and levels for Lithia Spring Major. Based on this limiting factor, a prescribed flow
reduction that permits consumptive-use of spring flows in excess of 1 cfs was
identified for consideration in the establishment of a minimum flow for Lithia
Springs Major.
Use of this prescribed flow reduction for development of a short-term compliance
standard for Lithia Springs Major was not considered appropriate for several
reasons. First, although a flow of 1 cfs from the spring may be sufficient for
meeting Department of Health requirements for public bathing places, allowing
withdrawal of all flows in excess of 1 cfs would likely result in adverse impacts to
recreational values. Flows as low as 1 cfs are uncommon at the site (see Figure
2-28), and would be associated with increased incursions of colored river water
into the typical clear spring run and pool, which would lead to decreased
availability of the pool for swimming and diminished aesthetic values. Second,
although the extent of aquatic habitat in the Lithia Springs Major run is not great
in comparison to habitat available in the Alafia River system, PHABSIM results
indicated that percent-of-flow reductions in excess of 15% may be expected to
result in more than a 15% loss of habitats in the spring run. Allowing spring flow
to be reduced to 1 cfs, a flow that represents a 97% decrease from the mean
annual daily flow for the spring, would therefore be expected to significantly
impact spring run habitat. For these reasons, we do not recommend use of the
prescribed flow reduction based on use of the pool as a bathing place for
development of a prescribed flow reduction or short-term compliance standard.
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