Project Summary Sheet

Project Title: Tides and Inflows in the Mangrove Ecotone (TIME) Model Development (Vegetative Resistance to Flow)

Project Start Date: October 1, 1999 Project End Date: September 30, 2004

Web Sites: time.er.usgs.gov

Location (Subregions, Counties, Park or Refuge): Everglades National Park, Big Cypress National Preserve

Funding Source: USGS's Greater Everglades Science Initiative (PBS)

Principal Investigator(s): Harry L. Jenter

Project Personnel: Kevin Kotun (National Park Service, Everglades National Park), Cheryl Lee (Environmental Careers Organization intern)

Supporting Organizations: National Park Service Everlades National Park

Associated / Linked Projects: Schaffranek, Langevin, Swain, Jones

Overview & Objective(s): The TIME Model Development project is focused on further developing, extending and implementing a mathematical model to study the interaction between wetland sheet flows and dynamic forces in the transition zone between the southern Everglades and its coastal embayments. The model will be used to study and evaluate the combined response of hydroperiods in the wetlands and salinities in the mangrove ecotone to inflow alterations.

Status: Two journal articles have been submitted to professional, peer-reviewed journals. These articles form the basis on which a vegetative resistance to flow formulation will be added to the TIME flow model. All relevant data sets for the June 1999 through August 1999 model simulations have been acquired, quality checked and formatted for model input. Additionally, much of the data that will be used eventually as input to the TIME model for other model simulation dates between January 1, 1995 and June 1, 2003 have been acquired and will be quality assured by the end of FY2003. NEXRAD rainfall data for the initial model calibration run has been processed and regridded to match model scales. A small, field experiment to better define the effect of wind on surface water flow is ongoing and will continue through the end of FY2003 until the end of the wet season in early 2004. Daily fluctuations of temperature in the water column are monitored at the same field sites.

Recent & Planned Products: The following journal articles have been submitted:
Lee, J.K.; C. Lai and H.L. Jenter. "A Pipe Manometer Method for Determining Wetland Water-Surface Slope" submitted to American Society of Civil Engineers' Journal of Hydraulic Engineering

Lee, J.K.; L. Roig; H.L. Jenter and H. Visser. "Vertically Averaged Flow Resistance in Free Surface Flow through Emergent Vegetation at Low Reynolds Numbers" submitted to Ecological Engineering, reviewed and in the process of resubmission.

Jenter, H.L.; R.W. Schaffranek and T.J. Smith, III. "Thermally-driven Vertical Mixing in the Everglades" in revision after unsuccessful submission to Science and Nature due to geographical narrowness of subject matter.

Jenter, H.L. and M.P. Duff. "The TIME Data System (TDS)". USGS Open-file report in draft. Expected submission September, 2003.

Relevance to Greater Everglades Restoration Information Needs: This subset of the TIME project is relevant to USGS Science Plan in Support of Everglades Restoration Science Objectives, Science Objective 1, Get the Hydrology Right (Water quantity, timing and distribution), in particular it is intended to address these questions:

• How do hydropatterns and flow affect the Greater Everglades ecosystem?
• What are the effects of vegetative resistance to flow?

Key Findings:

• Vegetative resistance to flow is directly correlated to two measurable parameters: a Reynolds number based on the average distance between plant stems and the ratio of that same distance to the water depth.
• NEXRAD rainfall data appear to be of sufficient quality and resolution to serve as an improved input data set for surface-water flow modeling at the temporal and spatial scales of the TIME model.
• There is a strong daily periodicity in the vertical profile of temperature throughout the water column, highlighted by a thorough mixing of the topmost 40 cm nearly every evening. This periodicity is driven by the air-water temperature difference to the near-complete exclusion of wind and rain effects.