Project Summary Sheet

Study Title: Freshwater Flows to Northeastern Florida Bay
Study Start Date: 1995 Study End Date: TBD
Web Sites: (http://sofia.usgs.gov/projects/freshwtr_flow/)
Location (Subregions, Counties, Park or Refuge): Miami-Dade and Monroe Counties, Everglades National Park
Funding Source: USGS Greater Everglades Priority Ecosystems Science (GE PES), U.S. Army Corps of Engineers (USACE)
Principal Investigator(s): Mark Zucker and Jeff Woods
Study Personnel: Christian Lopez, Shane Ploos, Carrie Boudreau, Stephen Huddleston
Supporting Organizations: USACE, South Florida Water Management District (SFWMD), Everglades National Park (ENP)
Associated / Linked Studies: Southwest Florida Coastal and Wetland Systems Monitoring, Coastal Gradients of Flow, Salinity, and Nutrients, Tides and Inflows in the Mangroves of the Everglades (TIME), Dynamics of Land Margin Ecosystems, Southern Inland and Coastal Systems (SICS) Model, Hydrology Monitoring Network: Data Mining and Modeling to Separate Human and Natural Hydrologic Dynamics, Compilation, Integration, and Synthesis of Water Quality and Flow Data for Assessing Nutrient Flux to South Florida Coastal Ecosystems, Everglades Depth Estimation Network (EDEN), FIU-Long Term Ecological Research (LTER), ENP Marine Monitoring Network, SFWMD Minimum Flows and Levels for Florida Bay.

Overview & Objective(s): The project objectives are to: (1) determine the quantity, timing and distribution of freshwater flow through estuarine creeks into northeastern Florida Bay (Fig. 1); (2) for Everglades modelers, scientists, and managers, provide up to 31 days of real-time hydrologic data, provide published unit value data on the South Florida Information Access website (SOFIA), and provide station manuscripts for the annual surface water data report; (3) advance acoustic methods and technology for gaging estuarine creeks; and (4) advance methods and technology for computing continuous water quality monitoring record (e.g. salinity). Flow, water-level, salinity, and temperature data are collected at the estuarine creeks that connect the Everglades wetland with Florida Bay. This project provides flow data critical for addressing nutrient loading and the impact of water quality on Florida Bay. The USACE, SFWMD, USGS, ENP and other agencies as well as universities currently are using the data from this study to answer specific research questions that will directly benefit the Everglades restoration effort.

Figure 1: Monitoring stations in northeastern Florida Bay and Joe Bay. [larger image]

Status: On-going

Recent Products: (1) Published unit values of water level, discharge, salinity, specific conductance and temperature are available from 1996 to 2006 (Surface and ground). Data is available on SOFIA at http://sofia.usgs.gov/exchange/zucker_woods_patino/index.html; (2) Published fact sheet (FS2004-3129) “Hydrologic Characteristics of Estuarine River Systems within Everglades National Park.” (http://water.usgs.gov/pubs/fs/2004/3129/) (3) Clickable map of real-time data for scientists and resource managers available on SOFIA; (4) Abstract and poster titled “Estimates of Nutrient Loads at West Highway Creek in Northeastern Florida Bay” was presented at the 2005 Florida Bay Conference (Shoemaker and others, 2005); (5) Circular article for the special estuaries addition on the 2004 hurricane season (Woods and others, in press); (6) Abstract and poster titled “Northeastern Florida Bay Estuarine and Joe Bay Estuarine Creek Data, 2001-2005” (Zucker and others, 2006) and “Northeastern Florida Bay Estuarine Creek Response During the 2004-05 Hurricane Season” (Woods and others, 2006) was presented at the 2006 GEER Conference in June 2006; (7) Contracted USGS National Mapping Division to verify and establish elevations at four surface water stations (B Glover, USGS, pers. commun., 2007) (8) Provisional nutrient loading data at West Highway Creek provided to SFWMD for the assessment of algal blooms in Florida Bay (SFWMD, 2006) (9) Abstract prepared in collaboration with Steve Davis at Texas A&M University for an LTER Scientists Conference (Davis and others, 2006) (10) Updated Florida Bay metadata on SOFIA; (11) Abstract and poster titled “A comparison of rated discharge at Jewfish Creek using a 0.5 MHz and a 1.5 MHz Argonaut-SL using different sampling volumes” presented at the 2007 National Surface Water Conference and Hydroacoustics Workshop, April 2007.

Planned Products: (1) Publish unit values of water level, discharge, salinity, and temperature for water year 2007 available on SOFIA no later than April 2008 (Surface and ground water); (2) Collaborative journal article using data from various PES projects titled “Estimates of Nutrient Loads at West Highway Creek in Northeastern Florida Bay” (in prep.); (3) Journal article titled “Spatial and temporal salinity patterns in Joe Bay, Everglades National Park” (in prep.); (4) Data Series Report or Open File Report documenting the 2001-2006 published data set; (4) Continue rating development at the recently installed East Creek and Alligator Creek to evaluate the utility of hydrologic correlation and implications of total flow to Florida Bay; (5) Install, maintain and provide real-time wind data at three wetlands sites; (6) An abstract titled "Nutrient loading at Card Sound Canal; a tidally driven canal that experiences highly stratified, bidirectional flow conditions" was recently approved for presentation at the USGS National Water-Quality Workshop at Galveston, Texas, November 5-9, 2007; (7) Manuscripts from Water Resources Data for Florida, 2006, Volume 2A: South Florida Surface Water USGS Water-Data Report FL-06-2A will be posted on the SOFIA; (8) Continue collaboration with Dr. Ken Odom on the optimization of the coastal monitoring network. A deliverables in fiscal year 2008 includes a journal article discussing the statistical analysis of the collected data.

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

This study supports several of the projects listed in the Department of the Interior (DOI) science plan (specifically, the C-111 Spreader Canal and CSOP; Additional Water for ENP and Biscayne Bay Feasibility Study; and Florida Bay and Florida Keys Feasibility Study) by (1) providing baseline hydrologic data for model calibration and verification, and for resource management; (2) providing long-term hydrologic and water quality data to determine trends in hydrologic response to storms, sea level rise, and restoration activities; (3) quantifying discharge at estuarine creeks to answer quantity, timing and distribution questions; (4) quantifying discharge at estuarine creeks for nutrient load calculations; (5) providing temperature data for biological studies; and (6) providing salinity data to support restoration criteria (i.e., performance measures).

Three restoration questions were stated in the executive summary of the DOI Science plan (p. 1) and maximizing cost-share opportunities and science coordination were emphasized. This study supports restoration question 1: “What actions will improve the quantity, timing, and distribution of clean freshwater needed to restore the South Florida ecosystem?” The monitoring network provides coastal discharge data for the majority of estuarine creeks in northeastern Florida Bay. The timing and distribution of freshwater deliveries to northeastern Florida Bay has been documented since 1996. In 2003, the USGS coastal and estuarine unit also began calculating nutrient loads at selected sites in northeastern Florida Bay and along the southwestern Everglades coast. The larger network has provided discharge information to researches to develop nutrient budgets and loading (Rudnick, 1999; Sutula and others, 2003; Davis, 2004; Levesque, 2004).

USGS synthesis teams have been coordinated to assess nutrient flux to South Florida coastal ecosystems (McPherson and others, 2006) and to conduct data mining and modeling to separate human and natural hydrologic dynamics (Conrads and others, 2005). The need to comprehensively address recent algal blooms in Blackwater Sound and adjacent basins has fostered a collaborative effort between the USGS and Federal, State, and local partners to determine the source of the problem and understand the persistence of the blooms (SFWMD, 2006).

Key Findings:

1. From 1996 to 2001, Trout Creek has consistently contributed roughly 50% of the total flow to northeastern Florida Bay. Since 2001, the percent contribution from Trout Creek relative to the total flow to northeastern Florida Bay is roughly 41%. Total flow since year 2004, excluding year 2005 due to higher than normal hurricane activity, is much lower than previous documented years. Precipitation records suggest that years 2004, 2006, and more than likely 2007 will be below average for the study area.
2. It has been reported in earlier reports that roughly 70% of the freshwater flow into northeastern Florida Bay enters east of Taylor Slough. A recent examination of percentage of flow and total flow indicates that the percentage of flow entering east of Taylor Slough (Trout Creek + Long Sound) since year 2002 is less than 70% of the total flow. For example, in year 2004 the percentage of flow east of Taylor Slough equaled 57.5%. It must be noted that in years where the percentage of flow east of Taylor Slough is less than 70% usually occurs when total flow roughly equals or is less than 200,000 acre-feet. Although calendar year 2007 is incomplete, current data suggests the possibility of below average flows to Florida Bay.
3. Water level differences between Taylor Slough and the C-111 basin drive flow direction in the southeastern Everglades, which is a critical issue for contaminant transport, flood management, and saltwater intrusion. For example, freshwater from Taylor Slough moves eastward towards western Joe Bay during major storms and is an important contributor of freshwater flow to Florida Bay through Trout Creek.
4. Hydrologic correlation has been employed to estimate non-instrumented estuarine creeks with reasonable success (i.e. Long Sound) but may not be applicable for other estuarine creeks in northeastern Florida Bay (Zucker, 2003).
5. The total annual flow to Northeastern Florida Bay for 2005 was the greatest measured since the project began in 1995. Coincidently, the lowest total annual flow to Northeastern Florida Bay occurred in 2004. The total annual freshwater flow to northeastern Florida Bay in 2005 equaled 515,920 acre-ft.
6. The flow distribution from five stations installed in water year 1996 was discussed by Hittle and others (2000) and Hittle and others (2001). Total annual flow in 1996, 1997, 1999, 2001, 2002, 2003, and 2005 was near or above 300,000 acre-feet whereas total annual flow in 1998, 2000, 2004, and 2006 was less than 300,000 acre-feet. Total annual flow in 2000, 2004, and 2006 coincided with drought-like conditions in south Florida, even though 2004 was considered an active hurricane season with four named storms impacting the state of Florida. Hittle and others (2001) discussed the flow distribution during the El Nino of 1998, in particular the impact on flow at McCormick Creek. Net negative annual flow was observed at McCormick Creek during the El Nino year of 1998 and during the drought year of 2000, but net negative annual flow was not observed during the drought year of 2004 or 2006.
7. Hyper-saline conditions at McCormick Creek coincided with the drought years 2000 and 2004 and non-drought years 1998, 1999, 2001 and 2005. In 2000, salinity conditions were greater than 35 ppt at McCormick Creek. On the other hand, salinity conditions in 2004 and 2005 were greater than 35 ppt at all stations and exceeded 40 ppt in Joe Bay in year 2005. The wet season salinity response in 2005 was variable except for the stations downstream of water management structures (C-111 Canal). Monitoring stations in Long Sound and eastern Joe Bay reported rapid changes in salinity reaching 5 ppt or less within 1 week of water-management operations. Monitoring stations such as McCormick Creek and Taylor River at the Mouth, located in the more western portion of the study area, reported a more gradual change in salinity with the onset of the wet season. Salinity at McCormick Creek dropped from 50 ppt to roughly 30 ppt and remained elevated until the passing of Hurricane Katrina. The salinity conditions at Taylor River at the Mouth did not reach fresh-like conditions (< 5 ppt) until the passing of Hurricane Katrina reaching 1.0 ppt by mid September 2005. A comparison of mean monthly salinities at McCormick Creek versus West Highway Creek allowed for an assessment of salinity distributions within the study area. To reiterate, mean monthly salinities for a given year at McCormick Creek and West Highway Creek were greater than 35 ppt 7 out of the last 11 years and 3 out of the last 11 years, respectively. A duration curve of mean monthly salinities indicated that the monthly median salinity at West Highway Creek for years 1996-2001 versus years 2002-2006 has increased from 8.5 ppt to 16.3 ppt. Mean monthly salinities at West Highway Creek have been greater than 35.0 ppt in years 2004, 2005, and 2006 indicating that Florida Bay was more than likely hyper-saline.