MANASOTA & PEACE RIVER BBDs Meeting Notebook 10-21-09.docx

B182
USGS Minimum Flows and Levels Data Collection - Myakka and
Braden Rivers and Cow Pen Slough
Project Type Basin Initiatives
AOR(s)
Water Supply, Natural Systems
Basin(s) General Fund (District), Alafia River, Hillsborough River, Coastal Rivers, Pinellas-Anclote River,
Withlacoochee River, Peace River, Manasota
Cooperator(s)
United States Geological Survey
Project Manager KELLY, MARTY
Task Manager(s)
Status Ongoing
Description
This initiative is to establish and maintain the District's gaging network needed to establish/re-evaluate minimum flows
and levels (MFLs) on priority waterbodies throughout the District. Beginning in FY2004, data collection associated with
MFLs was funded under a separate agreement with the U.S. Geological Survey (USGS). Until this time, funding for
these sites was included in a single activity with all other services provided by USGS (B063). For efficiency of project
administration, budget tracking, and because MFLs sites are funded by the respective basin boards, these sites are
now the subject of a separate agreement (B182). MFLs gage sites are viewed as "short term," and it is envisioned that
most sites will be maintained for approximately three to five years. While the USGS (with cooperative funding from the
District in recent years) has long maintained a stream gaging network in the state, coverage is not adequate for
establishing the most defensible MFLs. It is envisioned that short-term gage sites will routinely be established along
rivers to estimate flow at various distances along the river's length. Coupled with information from long-term gage
sites, a few years' records at these short-term gages can be used to establish more accurate flows in the vicinity of
biological monitoring sites used to evaluate and establish MFLs. Based on empirical relationships to be established
with long-term gages and using hydraulic modeling results, flow records can be re-created at short-term sites using
flow records at long-term sites. In addition, while the flow regimes of many of the District's rivers have been historically
monitored along their freshwater reaches, flow data for rivers where they enter their respective estuarine areas is often
lacking or has not adequately been monitored. The influence of tide and the braided nature of some of the rivers in
their estuarine reaches make discharge measurements difficult and costly. In addition to stage and flow data,
monitoring in tidal areas involves increased instrumentation to allow for salinity and sometimes dissolved oxygen
measurements to be made. Flows can greatly affect the distribution of salinity and low dissolved oxygen zones in
estuarine river reaches.
Benefits
Funding of this initiative allows for the development and establishment of MFLs according to the Board approved
priority list as mandated by state statute.
Costs
Funding is to maintain and in some cases to establish flow gaging sites which provide the fundamental flow data
necessary for establishing MFLs. Total requested funding in FY2009 is for $557,200. The cost split is 50
percent Governing Board ($278,600) with the remaining 50 percent from the Basin Boards apportioned according to
gage sites within their respective Basin. The increase in FY2009 funding reflects an annual adjustment to pricing by
the USGS and the addition of four new gage sites located on: 1) Brooker Creek (PA Basin), 2) North Prong Alafia
(Alafia Basin Board), 3) South Prong Alafia River (Alafia River Basin Board), and 4) Hillsborough River at Fowler
(Hillsborough River Basin Board). Monitoring in the Manasota Basin is projected to cost $169,800 in FY2009 with the
Basin's 50 percent share equal to $84,900 for continued monitoring at all pre-existing sites. The FY2010 budget is
projected to be $533,900 and will reflect the Governing Board's decision to completely fund MFL related projects
without matching Basin Board funds.
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