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Project ID: 2004FL57B

Title: Sensitivity of the Hydroperiod of Forested Wetlands to Alterations in Topographic Attributes and Land Use

Project Type: Research

Focus Categories: Ecology, Hydrology

Keywords: Wetlands, Hydroperiod, Modeling

Start Date: 03/01/2004

End Date: 02/28/2005

Federal Funds: $28,617

Non-Federal Matching Funds: $57,234

Congressional District: 11th

Principal Investigator:
Mahood Nachabe


Forested wetlands along the flood plains of over 10,000 miles of streams in Florida are considered Variable Saturation Areas (VSAs). These VSA's are inundated zones occuring in topographically low areas where they receive regional discharge fluxes from surrounding landscapes. As the name implies, a VSA varies with time—the saturated area shrinks during the dry season (October through April) and expands through the wet season (June though September). This spatial/temporal variation creates the forested wetland hydroperiod, a fundamental characteristic controlling plant and animal species in the wetland. The objectives of this research are to (1) model and physically measure landscape characteristics where a VSA can be formed, (2) understand the hydrological dependence of a VSA on surrounding landscapes and on the regional seepage fluxes from these landscapes, and (3) model and assess the impact of agricultural and urban land uses upstream on the hydroperiod of wetlands in VSAs.

Many counties in Florida continue to face unprecedented rapid agriculture and urban developments. Yet we do not fully understand how this development is impacting the hydrology of forested wetlands. This research will help set scientific foundations for understanding the relationships between land use change and the hydrology of forested wetlands. First, we will develop a digital elevation model and use it to identify the source and flow pathways of water originating from surrounding upland landscapes and entering the wetland. The topographic elevation from the identified pathway becomes the upper boundary for HYDRUS-2D, a two-dimensional saturated-unsaturated flow model capable of linking hydrological fluxes across different landscapes. The model will be calibrated with water-table observations along two flow pathways in Lithia in west-central Florida. The calibrated model will then be used to assess the impacts of changing surface boundary conditions associated with urbanization and irrigation.

Progress/Completion Report PDF

U.S. Department of the Interior, U.S. Geological Survey
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Last Updated: Friday November 4, 2005 9:31 AM
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