Cooperative Ecosystem Studies Unit, Hawaii Pacific Islands CESU

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US Geological Survey, Southeast Ecological Science Center, is offering a funding opportunity to a participating partner of the CESU for research designed to reduce uncertainty surrounding the backfilling of canals. The goal, to evaluate the benefits of sheet flow, vegetation interactions, and particle entrainment and redistribution along a spatial and temporal gradient of surface flow velocities outlined within the DECOMP Physical Model (DPM) cooperative program. Goal – Assess the large-scale direction and velocity of surface water within the DPM footprint. Numerous hypotheses outlined in the DPM Science Plan are dependent on an understanding of the hydrodynamics of flow pre and post operation of the L-67A culverts (S152). This includes understanding if flow is diverted around existing landscape features and the rate (velocity) which water flows through the DPM footprint. This information is critical in order to establish that the desired “flow-field” was established. Specific objectives are detailed below: This research centers on four fauna related hypotheses contained with the DPM Science Plan and to conduct large-scale hydrodynamics of surface water flows using sulfur hexafluoride (SF6) tracer methodology. Objective 1- Define the DPM flow-field. Conduct a study to determine the large-scale hydrodynamics of surface water flows between the L-67A and L-67C using sulfur hexafluoride (SF6) tracer methodology modified for the low-gradient Everglades. Conduct four SF6 tracer studies (1 per year, 2 before, 2 after) during the operational window (October through January). The tracer will be released immediately downstream of the L-67A culverts and the daily fate of the plume followed by making continuous measurements of SF6 concentrations using a GC mounted to an airboat. The plume will be followed for 5-10 days depending on dispersal rates. The results of the tracer tests, in combination with aerial photography to delineate landscape features, will be integrated with a Lattice-Boltzmann modeling procedure to develop fine-scale simulations of flow dynamics within the ridge & slough landscape, including vegetation interactions. High resolution elevation data and vegetation type, biomass, biovolume, and stem density data will be provided by USGS. Provide Annual report of results/findings by January 30, 2011. This includes coupling findings with the rhodamine dye studies conducted by USGS/SFWMD as a compliment the SF6 tracer studies to study the short-term local flow dynamics in ridges and sloughs. Dye will be introduced to 5-10 sloughs and sawgrass ridges in both the flow-way and control ridges and aerial observations will be made at regular intervals (hourly) to ascertain flow patterns. In addition, water samples for fluorescence detection will be collected from sentinel sites at 15-minute intervals.

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