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Project Work Plan

U.S. Geological Survey Greater Everglades Science Initiative (Place-Based Studies)

Fiscal Year 2004 Project Work Plan


Project Title: Freshwater Flows into Northeastern Florida Bay
Project Start Date: 10/1994 Project End Date: Ongoing
Project Funding: PBS, USACE
Principal Investigator: Clinton Hittle
Email address:
Phone: 305-717-5815/5852 Fax: 305-717-5801
Mail address: 9100 NW 36th St., Suite # 107, Miami, FL 33178

Project Summary:

In South Florida, changes in water-management practices to accommodate a large and rapidly growing urban population along the Atlantic coast, as well as intensive agricultural activities, have resulted in a highly managed hydrologic system. As a result, the natural hydrology of the Everglades ecosystem, including Florida Bay was altered. During the last few decades, Florida Bay has experienced seagrass die-offs, and algal blooms. Both are signs of ecological deterioration, which has been attributed to elevated salinities, and nutrient content of Florida Bay water. Plans to restore the timing and distribution of freshwater flow within the Everglades toward more natural conditions will affect discharges into Florida Bay. An understanding of the linkage between upstream water deliveries and the amount and timing of freshwater flow entering Florida Bay is an important aspect of Everglades restoration. Historically (prior to 1995), there was no accurate quantification of the amount of freshwater flow into Florida Bay due to the difficulties of accurately gaging flows in shallow, bi-directional, and vertically stratified estuarine streams.

In 1994, the U.S. Geological Survey (USGS) began a study of five estuarine creeks that discharge freshwater into northeastern Florida Bay. Currently, the monitoring network is composed of fourteen creeks. This study provides baseline discharge, salinity, and water-level data for model development/calibration and critical hydrologic data for other physical, biological and chemical studies. Data from this study has been provided to scientists working in the Everglades wetland/Florida Bay transition zone, which has improved our knowledge about this complex ecosystem.

Project Objectives and Strategy:

The project objectives are: 1) To determine the quantity, timing and distribution of freshwater flow through estuarine creeks into northeastern Florida Bay, 2) to provide real-time physical data to Everglades modelers and researchers, and 3) to advance accurate methods for gaging estuarine creeks. Flow, water-level, and salinity data are collected at the estuarine creeks that connect the Everglades wetland with Florida Bay. This project helps determine how freshwater flow affects the health of Florida Bay, a critical concern of the CERP, and how changes in water-management practices upstream (Taylor Slough and C-111 basins) directly influence flow and salinity conditions in the estuary. The U.S. Army Corps of Engineers (USACE), South Florida Water Management District (SFWMD), USGS, Everglades National Park (ENP) and other agencies as well as universities are currently using the data from this study to answer specific research questions that will directly benefit the restoration effort.

Potential Impacts and Major Products:

Flow and salinity data are critical for establishing performance measures used in the evaluation of CERP projects, such as the C-111 Spreader Canal and the Florida Bay/Florida Keys Feasibility Study (FBFKFS). Flow into Florida Bay affects salinity, nutrient and sediment transport, and chemical characteristics of the bay, which in turn, affect the health of the ecosystem. Everglades and Florida Bay researchers require discharge to compute nutrient, chemical, and sediment fluxes. These flux computations are then used in biological and physical studies of the Florida Bay ecosystem. Additionally, accurate measurements of freshwater flow, water level, and salinity are important because these data are inputs to various hydrologic and hydrodynamic models used to evaluate restoration alternatives. Accurate data are also useful for water-budget determinations and model verification. Decisions regarding restoration based on scenario testing from hydrologic and hydrodynamic models have a higher degree of confidence when the models use or are verified against field data. Lastly, there is an opportunity to compare the observed flow distribution prior to CERP implementation against the flow distribution as a result of the CERP plan.

Products include the development of multi-year data sets that correspond with the development of hydrodynamic models within Florida Bay and the Everglades wetlands and a completed water resources investigative report (WRIR) on developing methods for the accurate measurement of freshwater flows in estuarine conditions (WRIR 01-4164 by Hittle and others, 2001.)

Collaborators: USGS, ENP, USACE, SFWMD, DERM, Florida International University (FIU), University of Miami (UM), Texas A&M, University of Virginia, Louisiana State University (LSU).

Clients: USGS project "Tides and Inflows in the Mangroves of the Everglades" (TIME), USGS project "Southern Inland and Coastal Systems" (SICS),CERP; CERP RECOVER Monitoring and Assessment Plan (MAP), CERP Florida Bay Florida Keys Feasibility Study, FIU Long Term Ecological Research (LTER), SFWMD Everglades/Florida bay/Mercury Research.


Title of Task 1: Gaging Freshwater Flows into Northeastern Florida Bay
Task Funding: USGS Place-Based Studies Initiative, USCOE Cooperative Streamgaging
Task Leaders: Clinton Hittle, Mark Zucker
Phone: 305-717-5815,305-717-5852
FAX: 305-717-5801
Task Status (proposed or active): Active and ongoing
Task priority: High
Task Personnel: Clinton Hittle, Mark Zucker, Marc Stewart

Task Summary and Objectives:

Task 1 is the continuation of measuring freshwater flow from the Everglades wetlands into northeastern Florida Bay. Flow, water-level, salinity and temperature data are collected in real-time at monitoring sites in estuarine creeks and are transmitted via satellite to the USGS Center for Water and Restoration Studies in Miami, Florida.

The task objectives are: 1) to determine the quantity, timing and distribution of freshwater flow through estuarine creeks into northeastern Florida Bay. 2) To provide real-time physical data to Everglades/Florida Bay modelers and researchers, and 3) to advance accurate methods for gaging estuarine creeks

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

Data collection includes continuous 15-minute interval measurements of water level, water velocity, salinity, and temperature data and periodic measurements of discharge for acoustic Doppler velocity meter (ADVM) calibrations at West Highway Creek, Stillwater Creek, Trout Creek, Mud Creek, Taylor River at Mouth, upstream Taylor River, McCormick Creek, Jewfish Creek, Joe Bay 8W and Joe Bay 2E. Monitoring stations where only discharge and water-level are collected include East Highway Creek and Oregon Creek. Salinity only sites include Joe Bay 1E and Joe Bay 5C. Field data at the instrumented sites are recorded by an electronic data logger and transmitted every 4 hours by way of the Geostationary Operational Environmental Satellite (GOES) into the database of the USGS CWRS office. Non-transmitting stations include Joe Bay 1-2E, 5C, 8W, East Highway Creek and Oregon Creek. Boat mounted acoustic Doppler current profilers (ADCP) are used to measure discharge in the estuarine creeks mentioned above. The ADCP uses the Doppler shift in returned acoustic signals reflected by particles suspended in the water to determine the velocity of moving water. Discharge and flow direction are calculated using the doppler software package. The mean channel water velocity is calculated by dividing the total discharge (measured with the ADCP) by the cross-sectional area determined by the water level at the time of measurement. The cross-sectional area is computed by using the site-specific stage area ratings, which is a function of water level. Water-level data are collected with an incremental shaft encoder equipped with a pulley, stainless-steel tape, weight, and float inside an 8 in. (inch) polyvinyl chloride pipe stilling well.

A USGS Open File Report is planned for FY04 and FY05 that includes a data summary for the estuarine creeks between 1996-2000 and 2001-2002 respectively. All summarized data will be put on the SOFIA web page and NWIS database for retrieval.

Planned Outreach:

Field trips into the Everglades mangrove transition zone are routinely used to acquaint new researchers from ENP, USGS, USACE, SFWMD, and other institutions and universities with the unique Everglades ecosystem.

Volunteer for science positions are available to help increase the public knowledge of the Everglades and to help foster education in the natural sciences.


The USGS science plan restoration goal 1,objective 1A, states that "to get the hydrology right", the quantity, timing and distribution of freshwater flows including the structure and function of the ecosystem must be understood. One important goal of the CERP is to get the quantity, quality, timing and distribution of freshwater flows right to improve the Everglades ecosystem. The primary objective of the "Freshwater Flows into Northeastern Florida Bay" project is to accurately measure the quantity, timing, and distribution of freshwater inputs into Florida Bay.

By accurately measuring the flow at the estuarine creeks of northeastern Florida Bay, a comparison of flows before and after CERP implementation can be performed. Changes in the timing and quantity of freshwater that are delivered from the upstream watershed, along with natural variation of precipitation and evapo-transpiration affect distribution of freshwater to the coast. In order to understand how proposed management changes will affect Florida Bay and the adjacent Everglades wetlands, an accurate representation of flow and salinity will be needed near the coast.

According to the DOI Science Prioritization needs, "among the most important hydrologic questions not yet addressed is how to translate hydrologic targets for ecological needs into operating rules for water managers". The "Freshwater Flows into Northeastern Florida Bay" project can assist with this task because of our ability to measure real-time flows, water levels and salinities along the coast. Natural system modelers will have a unique opportunity to obtain real-time data in order to calibrate and verify models.

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