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Chapter 1 Minimum Flows and Levels - Southwest Florida Water ...

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they aren't getting enough particulates delivered to them or they dry up <strong>and</strong> die<br />

Use of PHABSIM analyses is not appropriate for relatively stationary species.<br />

This issue is discussed in greater detail in the published paper listed below,<br />

which proposes an alternative way to address mussels <strong>and</strong> instream flows.<br />

Basically, the recommended approach would be to map mussel beds in river<br />

segments <strong>and</strong> use the PHABSIM modeling system to examine changes in<br />

inundation depths <strong>and</strong> flow velocities with changes in river flows. This can be an<br />

arduous process but has been accomplished for a couple of streams in<br />

Tennessee <strong>and</strong> Alabama.<br />

Gore, J.A., J.B. Layzer, <strong>and</strong> J. Mead. 2001. Macroinvertebrate instream<br />

flow studies after 20 years: a role in stream <strong>and</strong> river restoration.<br />

Regulated Rivers 17: 527-542<br />

(3) Chapman's sedge (Carex chapmanii), a wetl<strong>and</strong> plant, is also stationary. Like<br />

the peninsular floater <strong>and</strong> most mussel species, individual plants cannot relocate<br />

in response to changing flows, although it likely that distribution of propagules is<br />

influenced by variations in flow. Existing st<strong>and</strong>s of the sedge could be mapped<br />

<strong>and</strong> hydraulic models used to predict inundation of the st<strong>and</strong>s under varying flow<br />

regimes. Information on preferred habitat variables (e.g., water depth <strong>and</strong><br />

velocity) could be developed <strong>and</strong> used to predict potential habitat availability for<br />

the species.<br />

(4) Bald eagle (Haliaetus leucocephalus) - Field observations <strong>and</strong> photography<br />

from blinds could be used to pinpoint the "use" / capture points of fish, etc., for<br />

individual eagles <strong>and</strong> then water velocities, depths, <strong>and</strong> substrate conditions<br />

associated with the points could be used to create habitat suitability curves. This<br />

would probably be a difficult <strong>and</strong> potentially unreliable process as the species is<br />

not entirely water dependant.<br />

(5) Hydric hammock, a natural community of the river's floodplain. Hydraulic<br />

models could be used to predict inundation patterns for this floodplain<br />

community, but it seems unreasonable that PHABSIM could be utilized for<br />

evaluating changes in this habitat type. Current District methods for establishing<br />

MFLs include analysis of inundation patterns for this <strong>and</strong> other floodplain<br />

communities.<br />

As part of its adaptive management approach the District continues to develop<br />

new <strong>and</strong> refine existing habitat suitability curves. Consultants have already<br />

refined some of the initial curves used in MFL studies to be <strong>Florida</strong> specific. The<br />

newer curves are consistent with the earlier curves though they exhibit a higher<br />

level of detail.<br />

9-9

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