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Project Summary Sheet

U.S. Geological Survey, Greater Everglades Priority Ecosystems Science (GE PES) Initiative and ENP's CESI

Fiscal Year 2006 Study Summary Report

Study Title: Modeling Hydrologic Flow and Vegetation Response across the Tamiami Trail and Coastal Watershed of Ten Thousand Islands NWR
Study Start Date: January 1, 2006   Study End Date: September 30, 2010
Principal Investigator(s): Dr. Thomas W. Doyle, Dr. Ken W. Krauss
Study Personnel: Dr. Ehab Meselhe, Dr. Rebecca J. Howard, Mr. Eduardo Patino
Total System Funding Source: USGS Greater Everglades Priority Ecosystems Science (GE PES) and ENP Critical Ecosystems Studies Initiative (CESI)
Location (Subregions, Counties, Park or Refuge): Ten Thousand Islands National Wildlife Refuge, Collier County, Florida, USA
Supporting Organizations: U.S. Geological Survey, National Wetlands Research Center, Lafayette, Louisiana, USA, University of Louisiana at Lafayette, LA
Associated / Linked Studies: "Western Tamiami Trail Flows - Baseline Information and Response to CERP" by Eduardo Patino, U.S. Geological Survey, FISC-WRS, Ft. Myers, FL

Overview & Objective: Major restoration projects have been proposed to restore freshwater flow across the Tamiami Trail (U.S. 41) into coastal marshes and estuaries of the northern Everglades including Big Cypress National Preserve and Ten Thousand Islands National Wildlife Refuge (NWR) with little or no understanding of the hydrologic coupling and potential impact to vegetation communities. Monitoring activities and models are needed to assess the hydrologic exchange across the Tamiami Trail and at the estuarine interface within the coastal watersheds of Ten Thousand Islands NWR. Under the proposed Picayune Strand Restoration Project, plugs and culverts will be installed to shunt more freshwater across the Tamiami Trail north-to-south akin to historic flows which will alter the stage, discharge, timing, and distribution of flow across the marsh/mangrove coastal margin. There is a critical need for current hydrologic and vegetation data to understand current processes and relations controlling hydroperiod, salinity, and plant succession under pre-project conditions and climate in order to build models and to predict how increasing freshwater flow and sea-level rise will impact future habitat quality and distribution. This study will establish a stratified network of gaging stations to monitor continuous water levels and salinity conditions associated with vegetation type and growth response and to produce a hydrodynamic model to predict changes in hydroperiod and salinity under different rates of freshwater inflow, pre- and post-project. Gaging stations will be surveyed to vertical datum to create a digital elevation model of both land and water surface that can be used to calibrate hydroperiod and salinity relations that control vegetation growth and succession. Model applications will be extended to predict vegetation migration and succession under changing freshwater delivery regimes and changing sea-level under projected climate change. Refuge personnel will benefit from the repository of observational data and interactive models for adaptive management purposes.

This study capitalizes on field expertise and existing decision support tools to assess the benefits and/or consequences of CERP hydrologic goals and projects on mangrove/marsh habitat for park and refuge lands of the Greater Everglades system. The primary goal of this study is to monitor and model surface water, groundwater, and evapotranspiration fluxes across a major hydrological barrier in south Florida (U.S. Hwy. 41, Tamiami Trail), and across the oligohaline-estuarine gradient of Ten Thousand Islands NWR. Hence, this research will record the rate and stage of water flow under varying climatic conditions (e.g., wet and dry season) across the coastal margin of Ten Thousand Islands NWR prior to and following implementation of hydrologic restoration outlined for the Picayune Strand Restoration Project (and Southern Golden Gate Estates Hydrologic Restoration). Overall project tasks and objectives include: gaging hydrologic conditions, surveying ground and water elevations, correlating hydroperiod and plant associations, and modeling/determining hydrologic coupling with vegetative assemblage.

Status: Received funding for FY 2006 (from GE PES; from CESI). Transferred back to Florida Integrated Science Center to support task of Edward Patino (quantifying western Tamiami Trail flows relevant to Ten Thousand Islands NWR).

Recent & Planned Products:


Doyle, T.W. & K.W. Krauss. 2006. Predicting marsh-mangrove response and ecotone migration under altered hydrologic flow and changing sea-level across Ten Thousand Islands NWR. Page 58 in 2006 Ecosystem Restoration Conference: Planning, Policy and Science, June 5-9, Lake Buena Vista, FL.

Doyle, T.W., K.W. Krauss, M. Melder, J.K. Sullivan & A. From. 2005. SELVA-MANGRO: an integrated landscape and stand simulation model for predicting mangrove forest growth and distribution across the Everglades coastal margin under changing climate. Climate Science in Support of Decision Making, U.S. Climate Change Science Program, November 14-16, Arlington, VA.

Krauss, K.W., T.W. Doyle, R.R. Twilley, V.H. Rivera-Monroy & J.K. Sullivan. 2005. Subsidy-stress in estuarine floodplains: evaluating hydroperiod as a growth constraint in mangroves. Estuarine Interactions, 18th Biennial Conference of the Estuarine Research Federation, October 16-21, Norfolk, VA.


Krauss, K.W and T.W. Doyle. Monitoring and Modeling the Hydroecology of Ten Thousand Islands National Wildlife Refuge. USGS Fact Sheet, National Wetlands Research Center, Lafayette, LA (in prep).

Funds for FY 2006 were delayed, hence, we will continue to install the network of waterlevel recorders, salinity loggers, flow meters, and a weather station in order to collect essential environmental data for constructing a water budget model of the watershed. Even so, we anticipate that the installation of only the salinity loggers will be delayed beyond October 2006; we have been diligent and resourceful with installation to date. We will begin preliminary modeling exercises with water level data that we have collected from June 2006 through September 2007. We will begin surveying water level recorders to a vertical datum and verify digital elevation models for Ten Thousand Islands NWR to provide a base of our modeling of water flows. We will initiate additional studies designed to link vegetation response (mangrove and marsh) to observed, or modeled, hydrologic patterns in Ten Thousand Islands NWR. We anticipate at least one scientific presentation (undetermined venue) and a USGS Fact Sheet (see above) describing eco-hydrologic research in Ten Thousand Islands NWR. An annual progress summary report will be submitted to highlight field activities, preliminary data, and significant findings of FY 2007. Upon project completion, we will produce a USGS Open File Report, USGS Scientific Investigations Report, or USGS Professional Paper for wide dissemination and at least two scientific journal articles addressing the hydrologic/salinity modeling results, vegetative growth and water use characteristics/modeling in response to hydrologic regime. We will also have calibrated a model for determining Ten Thousand Islands NWR water budgets that will be available to refuge and CERP planners for current and future assessments.

Relevance to Greater Everglades Restoration Information Needs [See Plan on SOFIA's Web site:]: The DOI Science Plan in Support of Ecosystem Restoration, Preservation, and Protection in South Florida (DOI Plan) defines three primary study elements needed as part of Southern Golden Gate Estates Hydrologic Restoration that we address in this monitoring, research, and modeling project. Ten Thousand Islands NWR is located on the hydrologic receiving end of the restoration project, which is designed to reduce overdrainage to adjacent public lands and trust resources. The three 'needed' elements (listed on pages 59-60, DOI Plan) include: (1) modeling to predict changes in hydrology and ecology in the Ten Thousand Islands NWR, (2) monitoring of water flows and water quality in receiving waters south of the project area, and (3) monitoring of ecological responses to hydrologic change.

Furthermore, this research falls into the auspices of "research to understand the impacts of restoration projects on hydrology, habitats, and wildlife on the Florida Panther and Ten Thousand Islands NWRs with focus on the following: improvements to hydrological modeling and synthesis of existing information" which are defined as program-level (GE PES-CESI) science tasks. This research partnership (science alliance) will also assist with two major Ten Thousand Islands NWR management plan tasks: (1) complete a water elevation and water quality monitoring program on the refuge (Task 1.2.3), and (2) monitor the impacts of sea level rise on refuge habitats (Task 1.2.6) (USFWS 2002, Comprehensive Conservation Plan for Ten Thousand Islands NWR).

Key Finding:

With our GE PES funding allotment (79K in FY 2006), we have hired contract labor (GIS Specialist and part-time University of Louisiana at Lafayette intern) and purchased equipment including water level gages (11), rain gages (4), and a meteorological station. We have coordinated with our partners and collaborators to schedule and begin deployment of water level gages in the Ten Thousand Islands NWR following the Greater Everglades Ecosystem Restoration meeting in mid-June. During this trip, we installed 7 water level recorders along a predetermined grid encompassing the marsh-mangrove complex of Ten Thousand Islands NWR. With the completion of this task, we currently have 10 water level recorders logging at 1-hr intervals within the brackish marsh (3), salt marsh (3), immediate ecotone (2), mangroves (1), and a small inlet parallel to Oil Pad Road. All recorders are along the south side of the Tamiami Trail. In early October, with FY 2006 CESI funds in hand, we plan to complete the task of water level recorder installation by adding an additional recorder along the immediate ecotone and three within the mangroves. We will also install four rain gages at various locations within Ten Thousand Islands NWR and a weather station (incl. PAR, RH, barometric pressure, wind speed and direction). The contract to build a fence around this structure was issued in August 2006; the fence will be constructed this month (September 2006).

We have obtained various aerial photo coverages of the Woods River watershed of Ten Thousand Islands NWR to assist with project planning and model implementation purposes. We are reviewing and contrasting historic vegetation and ecotone map sources dating back to 1927, 1940, and 1951 to conduct a change analysis of mangrove expansion within Ten Thousand Islands NWR with the construction of Tamiami Trail and hydrologic decoupling of the region. We have also conducted some simulations of the SELVA-MANGRO model of the Woods River Watershed at Ten Thousand Islands NWR to predict potential vegetation succession in the absence of hydrologic restoration and under impending sea-level rise. We have begun modifications of the SELVA-MANGRO model to incorporate a water use and evapotranspiration function for mangrove and marsh cover to achieve water balance calculations under different flooding and climatic conditions. We are developing a study plan to verify evapotranspiration estimates of models by investigating plant water use efficiency, local ET drain at each water level recorder, and regional ET drain as estimated by the weather station (Penman-Monteith modeling).

We are working with refuge personnel to analyze past vegetation data collected from Ten Thousand Islands NWR, and we have discussed plans to implement a vegetation sampling protocol of our own that will complement past collections but add specific modifiers for hydrology. In addition to understanding what hydrologic changes are anticipated in Ten Thousand Islands NWR with restoration, it is important to determine how these changes will affect existing vegetation.

Finally, we have transferred FY 2006 CESI funds to the USGS Florida Integrated Science Center (FISC) in support of USGS Hydrologist Eduardo Patino. Ed Patino will be providing flow data across the Tamiami Trail within our project boundaries by using a series of Doppler flow meters. These funds will support FISC field personnel and/or the purchase of additional Dopplers as needed.

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