[Parameters: Topic='LAND SURFACE', Term='LANDSCAPE', Variable_Level_1='RECLAMATION/REVEGETATION/RESTORATION']
Everglades Depth Estimation Network (EDEN)Entry ID: USGS_SOFIA_EDEN_proj
Abstract: The Everglades Depth Estimation Network (EDEN) is an integrated network of real-time water-level monitoring, ground elevation modeling, and water-surface modeling that provides scientists and managers with current (1999-present), on-line water-depth information for the entire freshwater portion of the Greater Everglades. Presented on a 400-square-meter grid spacing, EDEN offers a consistent and ... documented dataset that can be used by scientists and managers to:1) guide large-scale field operations, 2) integrate hydrologic and ecological responses, and 3) support biological and ecological assessments that measure ecosystem responses to the implementation of the comprehensive Everglades Restoration plan (CERP) from the U.S. Army Corps of Engineers in 1999.
Research has shown that relatively high-resolution data are needed to explicitly represent variations in the Everglades topography and vegetation that are important for landscape analysis and modeling. The EDEN project will provide a better representation of water depths if elevation variation within each 400-meter grid cell can be taken into account. The EDEN network provides a framework to integrate data collected by other agencies in a common quality-assured database. In addition to real-time network, collaboration among agencies will provide the EDEN project with valuable historic vegetation and water-depth data. This is the first time these data have been compiled and analyzed as a collective set.
Data Set Citation
Dataset Originator/Creator: Pamela Telis and Aaron Higer
Dataset Title: Everglades Depth Estimation Network (EDEN)
Dataset Release Date: 2007-11-01
Data Presentation Form: digital dataOnline Resource: http://sofia.usgs.gov/eden/
Start Date: 1999-01-01Stop Date: 2008-10-28
Vertical Resolution: 0.01
HUMAN DIMENSIONS > ENVIRONMENTAL GOVERNANCE/MANAGEMENT > WATER MANAGEMENT
TERRESTRIAL HYDROSPHERE > GROUND WATER
TERRESTRIAL HYDROSPHERE > SURFACE WATER > WATER DEPTH
TERRESTRIAL HYDROSPHERE > SURFACE WATER > WETLANDS
LAND SURFACE > LANDSCAPE > RECLAMATION/REVEGETATION/RESTORATION
HUMAN DIMENSIONS > ENVIRONMENTAL GOVERNANCE/MANAGEMENT > ENVIRONMENTAL ASSESSMENTS
Quality The EDEN monitoring network includes ground-elevation measurements and continuous water-level data.
Ground-surface elevation data were collected by the USGS at more than 50,000 points with an approximate spacing of 400 meters covering almost the entire Greater Everglades. The EDEN water-level network consists of hourly water-level data from 253 gaging stations (230 existing gaging ... stations and 23 new installations) and includes freshwater (nontidal) marsh gaging stations, boundary gages on canals, and coastal gaging stations operated by the Big Cypress National Preserve (BCNP), Everglades National Park (ENP), South Florida Water Management District (SFWMD), and USGS. The U.S. Army Corps of Engineers (USACE) and SFWMD recently documented or surveyed a majority of the hydrologic gages in the Greater Everglades to obtain correct values for converting water-level data from NGVD 29 to NAVD 88. The NAVD
88 datum is consistent in comparing water-level data across the Greater Everglades and computing accurate water depths.
Horizontal positions are established by GPS observations and are referenced to the North American Datum of 1983 (NAD83). The desired horizontal accuracy is +/- 15 centimeters. This level of accuracy is consistent with GPS differential techniques which use two stations - a high-quality dual-frequency GPS receiver base station and a roving GPS station. The density and accuracy of a given GPS data observation varies from a few meters to a few centimeters according to the Position Dilution of Precision (PDOP) in the study area. Generally if the PDOP is observed to be excessive, data collection is discontinued or the data are discarded. The PDOP is an indicator of the positional accuracy of the GPS that be can derived from the
current GPS satellite geometry, which varies continuously. Generally the smaller the PDOP number, the higher the data quality. The PDOP is a permanent part of the recorded data and is also included in the post processing procedures during reduction of the GPS observations to NAD 83. Where possible, the GPS base station has an ellipsoid height to an accuracy of two centimeters relative to the Continuously Operating Reference Stations (CORS) or the High Accuracy Reference Network (HARN), both operated by the National Geodetic Survey (NGS).
Source data (HAED) collected to better than +/- 15cm. Standard errors of cross-validation for the DEM range from ~7cm to 17cm depending on the EDEN subarea. This version is composed of new models created for WCA3N and the BCNP combined with the mosaic of two versions (i.e., eden_v002a for WCA1 and eden_v002c for all other EDEN subregions) that comprised EDEN_EM_JAN07. The previous mosaic
was selected based on analysis of model performance in the water depth estimation process. The WCA1 surface was produced by removing all "upland" AHF points as defined by a reclassification of the Florida GAP process. For WCA1, the krigging model was developed based on statistics from the entire EDEN domain (the process for eden_v002a production). For each other EDEN sub-area (i.e., the other WCAs and the National Park) region specific krigging models were developed and applied.
The EDEN domain was broken into a large number of equal-sized rectangles (cells) that in total are referred to as the "grid". Characteristics of this grid, such as location of the centroid, the representative area of the Everglades, elevation, and percentage of vegetation type, define the grid spatial parameters. To match the Airborne Height Finder (AHF) data sampling spacing, the spatial resolution or the dimension (in ground distance) of each grid cell is 400 meters on each side. The ground surface DEM development process is iterative as additional high accuracy elevation data (HAED) are collected, water surfacing algorithms improve, and additional ground-based ancillary data become available. The DEMs used in the EDEN analysis through the summer of 2006 rely on version HAEDbeta2 of HAED. However, this version was produced by using all available AHF points posted to SOFIA as of August 2007. To create a realistic region-wide elevation model for EDEN purposes, the elevation data were segregated by Water Conservation Areas and National Park boundaries so that local trends could be isolated, sub-region specific interpolation models could be developed, and realistic breaks in elevation along sub-region boundaries could be imbedded in a final, region-wide DEM, To date the best performing DEMs for all subareas have been produced using the geostatistical approach called "anisotropic ordinary kriging". The latest iteration of the EDEN DEM used in EDEN applications is referenced as eden_em_oct07.
The water surface model was created by the following steps: 1. Water-level data for all the EDEN gages is retrieved from an ftp server 2. Water-level data reported in NGVD 29 are converted to NAVD 88 3. Daily median water level is calculated 4. Linear interpolation is used to create boundary conditions along canals and levees 5. Radial Bias Function multiquadric interpolation of extended data (median water level from gages in marsh and interpolated values along canals) is used to generate continuous water level
surfaces daily 6. The continuous water surface is predicted on the EDEN grid (400m x 400m) 7. Water depth is estimated by subtracting the EDEN ground digital elevation model (DEM) from the predicted water surface The USGS retrieves water level data daily from 253 gaging stations including 225 telemetry-enhanced gages that record and transmit several water level values throughout the day, most hourly from recorders ranging from approximately 81 deg, 07 min 19 sec to 80 deg 13 min 05 sec West and from 25 deg 13 min 27 sec to 26 deg 40 min 47 sec North. An additional 28 gages do not have telemetry and are manually read and added to the network. All transmitted data are entered and stored in the National Water Information System (NWIS), a database operated by the USGS. There are a total of 240 gages used for water surface interpolation of the freshwater Everglades. All gages in the EDEN network are
operated and maintained by four separate agencies including Everglades National Park, South Florida Water Management District, Big Cypress National Preserve, and the USGS.
The EDEN monitoring network includes ground-elevation and continuous water-level data. The EDEN water-level network consists of hourly water-level data from 253 gaging stations (230 existing and 23
new installations) and includes freshwater (nontidal) marsh gaging stations, boundary gages on canals, and coastal (tidal) gages operated by the Big Cypress National Preserve (BCNP), Everglades National Park (ENP), South Florida Water Management District (SFWMD), and USGS. All gaging stations have telemetry equipment that provides data on a daily basis. Several of the new gaging stations are co-located where ongoing landscape studies have been conducted for several years. A 6-year (October 1, 1999 to September 30, 2005) dataset of baseline conditions was established for the EDEN water-level network prior to the implementation of CERP. Water-level gaging stations have been surveyed, until recently, to the National Geodetic Vertical Datum of 1929 (NGVD 29); however, this datum has inconsistencies in the
vertical network that have never been resolved for southern Florida. The U.S. Army Corps of Engineers (USACE) and SFWMD recently documented or surveyed a majority of the hydrologic gages in the Greater Everglades to obtain correct values for converting water-level data from NGVD 29 to the North American Vertical Datum of 1988 (NAVD 88). These and other data provided by BCNP and ENP have been used to create datum-correction values for the EDEN network gages, allowing historic water-level data to be converted from NGVD 29 the NAVD 88. Three methods were used to determine the correcton for a gaging station: 1. Differential or basic Global Positioning System (GPS) - a highly accurate satellite-based surveying system 2. Optical survey - a traditional line-of-sight survey from points of known elevation; and 3. CORPSCON 1 version 6.0 - a program that interpolates the difference between ground elevation in NAVD 88 and NGVD 29 for a given location specified by latitude and longitude, and further refined by using the VERTCON version 2.5 grid modified by USACE Jacksonville District to incorporate the CERP vertical control network established in 2001-2002.
Access Constraints None
Use Constraints None
Data Set Progress
Distribution Format: DEM, NetCDF and GeoTiff files; tables linked to data
Phone: 904 232-2602
Fax: 904 899-5097
Email: patelis at usgs.gov
701 San Marco Blvd.
Province or State: FL
Postal Code: 32207
Role: DIF AUTHOR
Email: alicia.m.aleman at nasa.gov
Goddard Space Flight Center Code 610.2
Province or State: MD
Postal Code: 20771
Pamela Telis, 2006, The Everglades Depth Estimation Network (EDEN) for support of ecological and biological assessments, USGS Fact Sheet, 2006-3087, U.S. Geological Survey
Jones, John W., Price, Susan D. 2007, Initial Everglades Depth Estimation Network (EDEN) digital elevation model reseach and development, USGS ... Open-File Report, 2007-1034, U.S. Geological Survey
Jones, John W., Price, Susan D. 2006, Conceptual design of the Everglades Depth Estimation Network (EDEN) grid, USGS Open-File Report, 2007-1200, U.S. Geological Survey http://sofia.usgs.gov/publications/ofr/2007-1200/
Pearlstine, Leonard, Higer, Aaron; Palaseanu, Monica; Fujisaki, Ikuko; Mazzotti, Frank, 2007, Spatially Continuous Interpolation of Water Stage and Water Depths Using the Everglades Depth Estimation Network (EDEN), CIR, 1521, Institute of Food and Agricultural Services, University of Florida
Full text of the document is available at: http://edis.ifas.ufl.edu/pdffiles/UW/UW27800.pdf http://edis.ifas.ufl.edu/UW278
Creation and Review Dates
DIF Creation Date: 2007-11-16
Last DIF Revision Date: 2008-12-31