Restoration of flow to the Kissimmee River: Five years of interim flow conditions

Restoration of ecological integrity in the Kissimmee River of central-southern Florida is predicated on reestablishing the physical form of the river channel and managing hydrology to mimic pre-regulation conditions.  Construction for Phase I of this project was completed in February 2001.  Since then, inflows from the upper basin have been managed with an interim stage regulation schedule.  As this project approaches completion, the interim schedule will be replaced with the new headwaters revitalization schedule, which allows for greater upstream water storage to provide pre-regulation inflows.  Ecologically significant characteristics of pre-regulation hydrology (based on 30 years of record) are represented in five expectations for the restored river -  1) continuity of inflow from the upper basin, 2) seasonal and annual variability of flow, 3) fluctuation of river channel stage, 4) stage recession rates, and 5) range of mean channel velocity.  This presentation uses these criteria to evaluate hydrologic conditions during five years of interim flow.  Several characteristics indicated improvement (long period of continuous inflow from the upper basin, a shift of the peak of mean monthly flow from the dry season to the wet season, and increased fluctuation of water levels).  However, these improvements did not always achieve the desired condition (extended periods of no flow occurred, some years contained multiple recession events, and some recession events were more rapid than desirable).  Implementation of the headwaters schedule should help resolve these issues.  Quantifying interim hydrologic conditions should aid the interpretation of other ecological responses to Phase I.