SWFWMD MINIMUM FLOWS & LEVELS
Summary of December 2-6, 1996 Meetings
Legislation passed in the last session required SWFWMD to set minimum flows and levels in
the Northern Tampa Bay WUCA by the fall of 1997. The SWFWMD decided to attempt to
have the methodology for setting these levels developed by a series of rule workshops held in
Tampa beginning on December 2, 1996. A Technical Committee and Community Issues
Committee were formed to develop the methodology. The current schedule requires the
scientifically based methodology to be developed by March 1997. The methodology would be
tested by SWFWMD staff from March through May, 1997. A draft of the rule would be
available by early summer, 1997 and the rule would go to the governing board in October,
1997. The Technical Committee will continue meetings on December 16-20 and tentatively
for the entire first week of January, 1997. Meetings beyond that date will be necessary but
have not been scheduled. The Community Committee meets after business hours and will
concentrate more on policy issues such as property values, etc.
The Technical Committee is made up of one representative from the following entities:
Florida Department of Agriculture Industry (Seminole Electric)
City of St. Pete City of Temple Terrace L i0 C. 'l-
City of Tampa WCRWSA F k CC
Coalition of Lakes Association Suwannee River WMD 3o 0 u fL/'
Department of Environmental Protection St. John's River WMD
Hillsborough County Environmental Protection Agency Southwest Florida WMD
Pasco County Local Governments
Hillsborough County Pinellas County
Hillsborough County Greenways Task Force Sierra Club
Tampa Bay National Estuary Program Environmental Advisory Council
The Water Management District representatives are also part of an informal statewide
committee that is working on this issue with the goal of developing a statewide methodology
for setting minimum flows and levels. This Northern Tampa Bay WUCA rule making is
likely to be the prototype for other WMD's to follow to develop their own minimum flows and
A summary of some of the findings of the statewide committee include the values and an
evolving model for establishing a method for setting the flows and levels. Values of setting
these levels include protecting the ecosystem, determination of available water to users, and
determine the best methods to operate flood control devices (refer to attached figures). The
model agreed to for creating a methodology is the attached figure "Establishment of Minimum
Flows and Levels Model". Implementation of the methodology may include triggering water
shortage rules (i.e. 40D-21), in water use permitting, and assistance in restoring areas such as
the Everglades. Other vehicles may also be used including development of alternative
supplies, demand management, and reservation of water.
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The committee decided to set levels on wetlands, lakes, and streams utilizing gauge data when
possible. However, it was concluded that setting minimum flows and levels on every wetland
lake or stream was impractical and therefore the concept of using surrogates was considered.
Surrogates would possibly be the Floridan Aquifer or the surficial aquifer. It was also decided
that surface features in wetlands could be used in conjunction with aquifer levels to set
minimum flows and levels. Levels that would be set would likely be multiple levels similar to
the Wekiva River Basin model as developed by the SJRWMD.
The concept of surrogates was discussed at length to determine which situations would be
appropriate for which surrogate. The attributes and detrimental aspects of using data only
from the surficial aquifer, data only from the Floridan aquifer, and a combination of both were
discussed ad nauseam. Consensus was reached on three items. The Floridan and surficial
aquifer levels were related in leaky or unconfined geological settings, the relationship between
these aquifers must be understood before minimum flows and levels were set, and that the use
of the Floridan aquifer data alone was inadequate for setting minimum flows and levels.
The issue of significant harm was agreed to be the most controversial portion of the rule
making. Although this was generally recognized as a policy decision, it was felt that
biological indicators could be used to make a scientific determination to guide the policy
decision. The committee decided that it would likely make recommendations to the Governing
Board that would include a range of options for the Board to adopt as significant harm. It was
also agreed that some harm to natural systems was allowed in the Statute.
Significant harm in wetlands was discussed and it was decided that a subcommittee of
scientists would evaluate data from as many wetlands as possible in the NTBWUCA. Data
seemed to be available from at least 50 wetlands with as many as 300 wetlands having some
data available. Information to be evaluated included soils, hydrological, and biological data.
_ The soils data would include the composition, lateral and vertical extent, and amount of
compaction with the primary concern being the amount of net loss of soils in the wetland.
Hydrological data would include evaluation of duration and frequency of inundation, seasonal
ranges, flow, and flood storage capacities. The biological data evaluated would include the
flora and fauna species, the stability of the species (including reproduction), and the
community structure. Other issues to be considered would be water quality, and the size and
location of wetlands in the landscape.
A separate subcommittee was also set up to evaluate data from lake systems in the
NTBWUCA. They were to evaluate both natural and man-made lakes including borrow pits,
etc. The subcommittee will take into account the current SWFWMD Lake Management
Levels Program methodology which includes setting levels in flood and drought conditions.
The lowest level set in this system is the 1 in 5 year drought. Issues identical to the wetlands
evaluation would be taken into consideration as well as the functional relationship between
hydrology and ecology, water quality, and bathymetry. They will evaluate 15 lakes and
create a test case.
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The Community Committee held it's first meeting on 12/5/96. The main focus of the
committee would be to determine how to implement minimum flows and levels. They also
discussed issues such as significant harm, aquifers to be used to set levels, restoration, and
social issues. No consensus on issues was reached.
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Purpose of Establishing
Minimum Flows & Levels
quantity for water allocations
Establishment of Minimum Flows and Levels Model
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