South Florida Information Access (SOFIA)

Project Work Plan

Department of Interior USGS GE PES
Fiscal Year 2012 Study Work Plan

Study Title: Greater Everglades Hydrology Monitoring Network: Data Mining and Modeling to Separate Human and Natural Hydrologic Dynamics
Study Start Date: 10/01/2004 Study End Date: 9/30/2012
Web Sites:
Location (Subregions, Counties, Park or Refuge): Total System
Funding Source: GE PES
Other Complementary Funding Source(s): none
Funding History: FY05 was the first year of funding for this project
Principal Investigator(s): Paul Conrads
Study Personnel: Paul Conrads, Matthew Petkewich, Andy Caldwell, Stephen Benedict, Jimmy Clark, Ed Roehl, and Ruby Daamen
Supporting Organizations: USGS-South Carolina Water Science Center

Associated / Linked Studies: South Florida Surface Water Hydrologic Network for Support of MAP Projects (Telis, PIs); Water Quality Monitoring and Modeling for the A.R.M. Loxahatchee National Wildlife Refuge (Brandt, Waldon, PIs); Estimation of Critical Parameters in Conjunction with Monitoring of the Florida Snail Kite Population (Wiley Kitchens, PI); Freshwater Inflows to Northeastern Florida Bay (Patino and Zucker, PI); TIME Model Development (Eric Swain, PI); South Florida Ecosystem History (Willard, PI); Aquatic Cycling of Mercury in the Everglades (Krabbenhoff, PI) Snail Production Assessment 1985-2005; (Darby, PI).

Overview & Objective(s): New technologies in environmental monitoring have made it cost effective to acquire tremendous amounts of hydrologic and water-quality data. Although these data are a valuable resource for understanding environmental systems, often these data are underutilized and/or under interpreted. The monitoring network(s) supported by the Comprehensive Everglades Restoration Plan (CERP) records tremendous amounts of data each day and the data base incorporates millions of data points describing the environmental response of the system to changing conditions. To enhance the evaluation of the CERP data base, there is an immediate need to apply new methodologies to systematically analyze the data set to address critical issues such as detecting change in hydrologic behaviors, water depths at ungaged locations, water-depths and water-quality responses to controlled flow releases, and relative impacts of controlled freshwater releases, tidal dynamics, and meteorological forcing on streamflow, water level, and salinity. There also is a need to integrate longer-term hydrologic data with shorter-term hydrologic data collected for biological resource studies. This study is undertaken as a series of studies (tasks) to demonstrate the efficacy of data mining techniques, including artificial neural network (ANN) models, to evaluate CERP data and address hydrologic issues important to DOI's efforts in South Florida.

The objectives of the studies for FY12 include: (1) documentation of the hindcasting of EDEN network to 1990; (2) working with Everglades Depth Estimation Network (EDEN) project team on Coastal EDEN and hydrologic analysis products; (3) continued hydrologic support of other PIs including Krabbenhoft and mercury studies; Brandt and the application of the Loxahatchee Empirical Model, and Darby and Kitchens and Snail Kite studies; and (4) development of a synthetic hydrograph generating application for EDEN.

Specific Relevance to Major Unanswered Questions and Information Needs Identified: (Page numbers below refer to DOI Science Plan.)

An important part of the USGS mission is to provide scientific information to manage the water resources of the Nation, including the other Agencies of the Department of Interior (DOI). The objectives for this study addresses science needs to support DOI managers in fulfilling their stewardship responsibility as identified in The Science Plan in Support of Ecosystem Restoration, Preservation, and Protection in South Florida (U.S. Department of Interior, 2004). This is consistent with primary USGS activities that include providing knowledge and expertise to assist various levels of government in understanding and solving critical water-resources problems.

The study objectives to develop hindcast hydrologic time series to generate water surface elevation and depth maps for EDEN and the network analysis of the EDEN network Coastal Gradient Network, and develop EDEN-products for the real-time evaluation of system response are part of the overall objective to support the South Florida Hydrology Monitoring Network and the Monitoring and Assessment Plan (MAP). The MAP was developed as the primary tool to assess the system-wide performance of the CERP by the REstoration, COordination and VERification (RECOVER) program (p. 17, DOI Science Plan). The MAP describes and outlines the monitoring and supporting enhancement of scientific information and technology needed to measure the responses of the South Florida ecosystem to CERP projects.

The study objectives of the documentation of EDEN hindasted hydrology to 1990, the development of EDEN-products for real-time system evaluation, continued support of the of the hydrologic and water-quality response models for the Arthur R. Marshall Loxahatchee NWR, and continued hydrologic support of mercury and snail kite studies meets a stated need in the Science Plan for the "synthesis and integration of data about historic hydrologic and ecological conditions on the refuge" and "research to understand the ecological effects of hydrology and water quality on refuge resources" (p. 37 and 40, DOI Science Plan). The study objectives will benefit the DOI and other Federal and State Agencies in South Florida by providing data analysis needed by water-resource managers to make decisions concerning the quantity and quality of water resources in the Everglades.

Many of the objectives of the studies support the Water Conservation Area 3 Decompartmentalization and Sheetflow Enhancement Project (DECOMP) by addressing the science needed for "...additional research to understand the effects of different hydrologic regimes and ecological processes on restoring and maintaining ecosystem function"? (p. 64, DOI Science Plan) and supports ecological studies of impacts of hydrologic change on the chemistry and ecology. The study also supports the Combined Structural and Operational Plan project (CSOP) by addressing the needed science for "refinement of hydrologic targets and operating protocols (p. 63, DOI Science Plan)."

Status: There were four objectives for the FY11 of the Data Mining Study:

  1. Hindcasting of the EDEN network to 1990,
  2. Work with the EDEN project team on hydrologic analysis products, including Coastal EDEN,
  3. Link paleocological and hydrologic timeseries, and
  4. Continued hydrologic support for other PIs.

The first objective was partially completed in FY11. The hindcasting of the EDEN database will be completed in FY12. The second objective has been partially met. The EDEN team has various hydrologic analysis products developed in FY11 that are in various stages of prototyping. The third objective was met with promising results. We'll be working with Christopher Bernhardt on interpretation and validity of the rainfall driven vegetation models. The fourth objective was met and we continue to interact on hydrologic issues with a number of PIs.

Recent Products: Products from FY11 of the study included (1) consultant report entitlted, "Quantifying How Stage Variability Affects Plant Species Populations in the Loxahatchee National Wildlife Refuge" by Paul Conrads (USGS) and Edwin Roehl (ADMi), (2) Five oral presentations and 1 poster were presented at USGS Conferences

National Surface-Water Conference and Hydroacoustic Workshop


Planned Products: Major products include: (1) database of hindcasts of for EDEN network to 1990; (2) Scientific Investigation Report (SIR) on hindcasting the EDEN data to 1990; (3) SIR on detecting change in water-level behaviors at selected sites in the Everglades, (4) prototype of EDEN-Syn applications: and (5) posters and presentations for the INTECOL/GEER Conference.


Title of Task 1: EDEN technical support: hindcasting.
Task Funding: USGS Priority Ecosystems Science
Task Leaders: Paul Conrads
Phone: (803) 750-6140
FAX: (803) 750-6181
Task Status: Active
Task priority: high
Time Frame for Task 1: 2012FY
Task Personnel: Paul Conrads, Andrew O'Reilly, and Matthew Petkewich

Task Summary and Objectives: The Everglades Depth Estimation Network (EDEN) was established to support the South Florida Hydrology Monitoring Network module of the Comprehensive Everglades Restoration Plan (CERP) and the Monitoring and Assessment Plan (MAP) and Restoration Coordination and Verification Team (RECOVER). The goals of EDEN are to help guide large-scale field operations, integrate hydrologic and biologic responses, and to support the MAP assessments by scientists and principal investigators across disciplines. One objective of EDEN is to relate water-level data at real-time stage gages to ungaged areas using ground elevation data, so that water depths throughout the greater Everglades can be estimated (Telis, 2005: ).

There is interest among PIs and water-resource managers for EDEN to generated water-surface and water-depth maps prior to 2000. The maps would enable analysis of disparate data prior to 2000 with the hydrology of the EDEN maps, using the suite of available EDEN applications. As one moves back in time, the quantity and quality of available data diminishes. An objective of the EDEN hindcasting effort will be to identify period where long-term hydrologic time series will support hindcasting and to hindcast particular conservation areas for generating water-surface elevation maps rather than the entire freshwater EDEN domain.

Work to be undertaken during the proposal year and a description of the methods and procedures:

The hindcasting effort has been larger than originally anticipated. The majority of the effort was completed in 2011 and 2012 will be spent on finalizing individual time series, evaluating water level surfaces, compiling performance statistics for the hindcasting models, and summarizing the approach is a report.

Specific Task Product(s):

  1. Database of 1990 -2000 hindcasts in the EDEN database
  2. Hindcasts available on EDEN website
  3. Compilation of hindcast model performance statistics
  4. Report on the Hindcasting effort.

Title of Task 2: EDEN technical support: Development of EDEN-hydrologic products including Coastal EDEN
Task Funding: USGS Priority Ecosystems Science
Task Leaders: Paul Conrads
Phone: (803) 750-6140
FAX: (803) 750-6181
Task Status: Active
Task priority: High
Time Frame for Task 2: 2012FY
Task Personnel: Paul Conrads, Stephen Benedict, Matthew Petkewich

Task Summary and Objectives: Performance measures are being developed to determine conditions that are characteristic of a healthy ecosystem for use in evaluating the restoration of the Everglades. Two potential targets of performance measures are 1) improved sheet-flow patterns for restoration of surface-water depths and duration to pre-drainage levels, and 2) the reduction of salinity fluctuations from freshwater pulses. The Everglades Depth Estimation Network has provided principal investigators and water-resources managers with quality-assured water levels for 300 stations for the period January 1, 1991 to the present (2011). EDEN-derived products could provide tools for real-time evaluation of current conditions and restoration performance measures.

One product is the daily water-level duration hydrograph: a plot of water-level percentiles (based on historic daily average water level for each day of the year) against the days of a calendar year. A daily duration hydrograph can be used to statistically quantify the water level observed at a gaging station. In addition to the historic distribution of water level, a trace of daily water level for the current year can be plotted on the duration hydrograph. The severity and trend of dry or wet periods at a gaging station can be determined by comparison of the current daily water-level trace on the hydrograph.

The duration hydrographs may be of utility for ecologists to summarize the hydrologic history for the period, but it is more difficult to evaluate a particular operational plan for water levels. The historical period used to compute the duration hydrographs can be selected to target a particular operational period. For example, if the intent of a new Interim Operational Plan (IOP) is to generally lower water levels from the previous IOP, the duration hydrograph can be based on period of the old IOP (2002-2011) and the current condition with the new IOP is shown as it relates to the previous IOP.

A second product is daily duration water-level and salinity hydrographs for particular stations of concern for evaluation of performance measures. The Southern Estuaries Performance Measure for Everglades Water Levels lists water-level stations that are "significant" explanatory stations for understanding the salinity response in Florida Bay. The Performance Measure pairs the water level of NP67 with the salinity in Joe Bay and the water level of P33 and the salinity of the North River. The intent of the Performance Measure is to achieve targeted lower salinity in Joe Bay and the North River by maintaining higher water levels at NP67 and P33. Duration hydrographs of water levels and salinity clearly show the salinity response to upstream water levels.

The principal focus of "Coastal EDEN" is the oligihaline/mesohaline zone in the Southern Everglades. These coastal areas are critical in evaluating the hydrologic and ecological responses to modifications of the water delivery system from restoration and future climate change. Hydrologic changes, either from flow alterations or climate change, will first be manifested along the coastal fringe. These areas experience tidal backwater conditions, and increases in flow and (or) sea-level rise may move this seaward or landward. Coastal areas will probably exhibit larger relative changes in hydroperiods as compared to inland areas.

There are EDEN-products for Coastal EDEN that have been prototype and need to be incorporated into the EDEN web pages. On product for Coastal EDEN are current and recent hydrologic and salinity condition maps. Water level, flow, salinity, and temperature data would be displayed with color codes for ranges of conditions for current real-time conditions or average conditions over the recent past (7-, 14-, 28-day). In addition, the change in conditions can also be shown, such as the 1-week or 1-month change in temperature or salinity at a site. For sites with longer periods of record, the current condition can be shown with respect to the historical ranges of percentiles. The data also can be displayed in tabular format.

Another Coastal EDEN-product is a web-accessible database of the Coastal EDEN stations. Similar to the current EDEN web portal for the freshwater portion of the Florida Everglades, the Coastal EDEN data portal will allow users to download quality-assured historical data from various agencies for user-defined periods; provide metadata on station location, operation, period of record, measured parameters, etc.; and deliver derived products such as daily water surfaces and water depths.

Work to be undertaken during the proposal year and a description of the methods and procedures:

The prototyped EDEN-products will be automated for real-time updating on the EDEN webpages. These will include duration hydrographs at selected stations. The critical element for making the Coastal EDEN products available is the automation of the database updates for the coastal data. Once automated, the coastal conditions map, paired water-level and salinity duration hydrographs, and the database itself, will be available.

Specific Task Product(s):

  1. Duration hydrographs of selected water-level stations.
  2. Automatic updating of coastal database and database available on line.
  3. Real-time coastal conditions map.
  4. Paired water-level and salinity duration curves to evaluation water-level performance measures.

Title of Task 3: Continued hydrologic support of other PIs including Krabbenhoft and mercury studies; Brandt and alligator studies and A. R. M. Loxahatchee National Refuge hydrologic management issues, and Darby and Kitchens and Snail Kite studies, and (or) Robert Sobczak with Big Cypress National Preserve
Task Funding: USGS Priority Ecosystems Science
Task Leaders: Paul Conrads
Phone: (803) 750-6140
FAX: (803) 750-6181
Task Status: Active
Task priority: high
Time Frame for Task 3: 2012FY
Task Personnel: Paul Conrads and Stephen Benedict

Task Summary and Objectives: Hydrologic support for other PIs will continue into FY 2012. Described below are some hydrologic analysis approaches and products that have been useful to PIs and will be expanded on in 2012. A systematic approach to analyzed historical data for periods of different hydrologic behaviors was applied to water level time series in WCA3a proximal to a long-term mercury sampling location. Cumulative Z-scores were computed for 35-year water-level data and plotted versus time. Changes in the slope of the cumulative Z-score indicate changes in hydrologic behaviors. Frequency distributions of water levels for 5 periods were graphed and shifts in the frequency distribution from 1992-2000 to 2001-2007 shows that there was about 0.5 feet shallower after 2000. Results of analysis help explain changes in mercury cycling in WCA3a.

The analysis will be expanded to include additional sites near ACME samplings sites and alligator survey transects. The analysis will include the long-term period of record at a water-level sites (the longest period of record will be different between the sites) and for a concurrent period of record between the water-level sites. The analysis of the concurrent period of record will allow for the comparison of water-level behaviors between the conservation areas. The results will be summarized in a USGS Scientific Investigations Report and will be citable for PIs using the results in journal articles.

To analyze and understand the interaction of natural and societal systems, data-collection networks are needed to quantify anthropogenic influences on natural systems. The ideal data collection network would provide a spatially and temporally extensive record of the interactions between natural and societal systems. With funding and logistical challenges in maintaining gaging networks, there is a need to evaluate networks to understand the uniqueness of the information from the network.

Time series cluster techniques have been developed and to group hydrologic time series of similar behaviors. Cross-correlation matrices were generated for the stations with the same parameters. The Pearson coefficient in the matrix is a measure of the correlation between each station in the network. The clustering routine computes the average distance between the vector (Pearson coefficient) and the mean value of a cluster. The optimal number of clusters is determined by maximizing the reduction of the distance measure with groups (RMSE) and minimizing the number of groups. The technique was applied to the USGS Coastal Gradient Network to group gages into similar class and then rank the gages in each class by uniqueness of hydrologic information. In FY12 similar analysis will be done for the network in Big Cypress National Preserve (BCNP) and the EDEN network.

Work to be undertaken during the proposal year and a description of the methods and procedures:

The Z-score analysis will be expanded and documented. The BCNP and EDEN networks will be analyzed this year.

Specific Task Product(s):

  1. The Z-score application will be documented in a USGS SIR report.
  2. Results from the network analyses will be incorporated into the planning document of EDEN and BCNP.

Title of Task 4: EDEN technical support: Development of the synthetic hydrograph generating application for EDEN
Task Funding: USGS Priority Ecosystems Science
Task Leaders: Paul Conrads
Phone: (803) 750-6140
FAX: (803) 750-6181
Task Status: Active (first year)
Task priority: high
Time Frame for Task 4: 2012FY
Task Personnel: Paul Conrads, Ed Roehl, and Ruby Daamen

Task Summary and Objectives: The EDEN has provided principal investigators and other water-resources managers with quality-assured water-surface maps for the period January 1, 2000 to the present (2011). There is interest among principal investigators and water-resource managers to use the EDEN water-surface model to generate water-surface maps for hypothetical hydrologic conditions. The use of the EDEN water-surface model for hypothetical conditions is challenging due to the need for daily model inputs for 240 monitoring stations within the freshwater domain of the Everglades. To generate a 10-year simulation with the EDEN water-surface model would require defining over 875,000 data points. The synthetic input hydrographs also must reflect the dynamic relations of timing and magnitude between stations for the water-surface model to execute successfully. The limitations of the number of input stations, the number of input values, and historical dynamic relations between the stations were addressed by using a sub-domain (subarea) model of the EDEN model domain and thereby limiting the number of gages to those of the subarea.

The objective of the EDEN-Syn development is to minimize the number of station hydrographs that a user needs to determine, to minimize the number of values for a user to input to define a 10-year daily water-level hydrograph, and to maintain the dynamic correlations between all the water-level input stations. An experimental subarea water-surface model was developed for Water Conservation Area 3A-South (WCA3AS) that uses 31 real-time stations from the EDEN network to generate water-surface elevation maps.

The generation of synthetic hydrographs for input into a subarea model of EDEN adds an important utility for EDEN users to be able to simulate hypothetical water-management scenarios. Previously, EDEN had solely been used to simulate historical conditions and users could ask "what was" the water level at an ungaged location on a particular day. By generating synthetic hydrographs, users can now ask "what if" a certain hydrologic conditions occurred and what would the water level be at an ungaged location on a particular day.

Work to be undertaken during the proposal year and a description of the methods and procedures:

To determine the minimum number of stations that a user will need to input to the application, a dynamic time-series clustering technique will be used to cluster time-series data into classes of similar behaviors. For each class of stations, the gage with the highest correlations with the other stations in the class will be selected as an index station and used to estimate the other stations in the class. Of the two index sites for each type of data, one will be selected for the user to input water-level values.

There will be three user input options in EDEN-Syn; a percent of the historical values, the percentile of the frequency of historical water levels, or a constant value for the month The user inputs a monthly value and EDEN-Syn will generate a daily values for the month. After the two user input hydrographs are entered, the user selects to generate the synthetic hydrographs for the other 29 stations in WCA3AS and the estimation models generate the synthetic hydrographs.

Specific Task Product(s):

  1. Determine the "index" stations for the application.
  2. Develop estimation model for station is WCA3AS.
  3. Design user input form.
  4. Test prototype EDEN-Syn application.