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Project Summary Sheet
Fiscal Year 2005 Study Summary Report
Project Title: High Accuracy Elevation Data Collection Project
Overview & Objective: Modeling of sheet flow and water surface levels in the Florida Everglades is very sensitive to changes in elevation due to its expansive and extremely low relief terrain. This project is applying state-of-the-art Global Positioning System (GPS) technology to perform topographic surveys that meets a vertical accuracy specification of ±15 centimeters (6 inches). The objective is to complete a wide-area regional topographic survey that will provide elevation data to parameterize hydrologic and ecological models used for ecosystem restoration.
Status: All Interagency Agreement commitments were completed for Airborne Height Finder (AHF) topographic surveys, and the development and delivery of Digital Elevation Models (DEMs) for Water Conservation Area 2 (WCA-2) funded by CERP/MAP. AHF surveys were also conducted in the eastern portion of Big Cypress National Preserve. In addition to the AHF field surveying campaigns, ten more static GPS surveys were performed to expand the AHF geodetic control network. Seven additional geodetic control sites were also reconnoitered for future surveys. This project has also continued in FY05 to perform static GPS surveys to accurately position water level gages throughout the Everglades. Ten USGS gages were completed. Fieldwork for 18 Everglades Depth Estimation Network (EDEN) gages will be completed by the end of FY05. Plans for FY06 are underway and include AHF surveys within the northern portion of Water Conservation Area-3 (WCA-3) north of Alligator Alley.
Recent & Planned Products: The topographic surveys are being performed using differential GPS technology, and a USGS developed helicopter-based instrument known as the Airborne Height Finder (AHF). In some areas, the surveying has been accomplished using airboats. The primary products being developed by this project are Digital Elevation Models (DEM's) that define the topography of the Everglades. The DEM's are organized by USGS quadrangles and are posted on the South Florida Information Access website (http://sofia.usgs.gov) once approved for release. To date, there are 70 DEM files posted on the SOFIA web site for data distribution. Another major accomplishment has been the surveying of many water level gages distributed throughout the Everglades. A database, or gage gazetteer, of the gage sites has been produced. The gazetteer contains a table of gage sites whereby the user clicks on a name and a data sheet is displayed containing the 3-D position of the reference mark and a photograph of the gage site.
Relevance to Greater Everglades Restoration Information Needs: The project supports the restoration and resource management efforts by providing critical data for the parameterization of numerical hydrologic and ecological models. Water resources and land management decisions will rely heavily on the results of these simulation models. It is imperative to derive and use the most accurate elevation data available for the models to produce meaningful results.
Key Finding: The AHF system is the superior technology for conducting a wide-area topographic survey of the Florida Everglades where the terrain surface being measured is inundated by surface water and obscured by vegetation.
U.S. Department of the Interior, U.S. Geological Survey
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Last updated: 04 September, 2013 @ 02:08 PM(KP)