calculated for each profie, the relationship between top width and flow was plotted. A 15%

reduction was then made to the top width at each flow profile in each model. The generated

relationships between top width and flow were then used to calculate the flow required at the

downstream gage sites to achieve the reduced top widths. The flow needed to achieve the non-

reduced top width and the flow required to maintain the top width minus 15% were then

compared to determine the percent of flow reduction required to reduce the top width by 15

percent.

 Results

 The vegetative surveys on the Alafia, Myakka and Peace rivers resulted in the

identification of different features of interest on each river. For the Alafia River, elevations of

eight floodplain features were identified at each of the eight vegetative cross-sections where they

occurred (Table 3-2). For the Alafia River, the downstream gage at which flow requirements

were compared is the USGS Alafia gage at Lithia (USGS# 02301500). Flow requirements, for

inundation of each feature ranged from 22.2 m3S-1 to reach the floodplain wetted perimeter

inflection point to 64.2 m3 S-1 to reach the low bank elevation for inundation of both sides of

river floodplain. Relatively high standard deviations, for the required flows, indicate that the

flow requirements for some features differed greatly among cross-sections. Flow reduction

resulting in 15% fewer days of inundation for the floodplain features, ranged from 5% for the

low-bank elevations and highest floodplain vegetation class to 9% for the highest swamp class

and floodplain wetted perimeter inflection point. Comparison of percent-of-flow reductions,

associated with the temporal loss of feature inundation between the two benchmark periods,

indicate that the 1970 to 1999 benchmark period provided the more conservative flow reduction

(Kelly et al. 2005a).