The Florida Inlets Program

Figure 1. SE Florida Inlets

Surface water from southeast Florida is conveyed to the coastal ocean through a several inlets (Figure 1). There is general agreement that these inlets are likely to be significant vectors of land-based pollution into the coastal ocean. However, determination of definitive mass balance loading (fluxes) from these inlets has not been possible due to the lack of water quality and hydrological data. To fill that important gap, we have endeavored to conduct a series of experiments to measure the flux of chemical and biological materials through several of these inlets. These programs are described below.

1. Boynton Inlet

Figure 2. The Boynton Inlet.

To calculate the mass flux through the Boynton inlet (Figure 2), both the volume of water and the concentrations of potential pollutants exiting this inlet on outgoing tides need to be measured. We conducted two 48-hour sampling intensive studies at the Boynton Inlet. Each involved multiple samples taken over a 2-day period, with four outgoing (ebb tide) and four incoming (flood tide) pulses of flow.

The intensives were conduced on June 3-4 and September 26-28, 2007. These samples were investigated for chemical and biological properties. In addition, high-quality water flow measurements were conducted. In addition to the sampling intensives, the flow through the Inlet was measured for a time period exceeding one year (February 2007 through October 2008) using a calibrated horizontally-directed acoustic Doppler current profiler (ADCP). The results on the program are available in two NOAA technical reports, Boynton Inlet 48-hour Sampling Intensives, June and September 2007, OAR-AOML-40, 2011 (pdf), and Boynton Inlet flow measurement study, OAR-AOML-43, 2013, 13 pp.(pdf).

2. Pt. Everglades Inlet

Figure 3. Port Everglades.

Port Everglades is a major seaport and as well as a connection of the Intracoastal Waterway into the Atlantic Ocean (Figure 3). To calculate the mass flux through the inlet, NOAA initiated the Port Everglades Shipping Channel (PESC) Study. To measure the flow through the inlet, we installed a 300-kHz HADCP (Teledyne RD Instruments) in February, 2009, on the south side of the Port Everglades inlet (Figure 2). The instrument was in place until 2011. In addition, a number of meteorological instruments have been installed on the south side of the inlet (26°5.549' N, 80°5.532' W). The instrumentation includes: wind speed and direction, relative humidity, dew point, barometric pressure, and rain parameters. The instrumentation has the designation as Buoy PVGF1 of NOAAs National Data Buoy Center, and of station PVGF1 of NOAA's CREWS/ICON coral reef monitoring program. Measurements of chemical concentrations were conducted by FIU for the estimation of chemical fluxes through the inlet. The report, Port Everglades Flow Measurement System, NOAA Technical Report OAR-AOML-42, is available here (pdf).

3. Boca Raton and Hillsboro Inlets

Figure 4. Hillsboro Inlet.

Figure 5. Boca Raton.

While not significant shipping ports, the inlets at Boca Raton and Hillsboro are significant drains of surface runoff from high population districts and of canal water through the Intracoastal Waterway. NOAA has conducted a study of those inlets, including a series of experiments at both inlets consisting of 1) four sampling and current measurement intensives using a small boat with down-looking ADCP instrumentation, and 2) biweekly grab sample analysis of water from the inlet over the course of a year. These data are currently being employed to provide estimates of the fluxes of materials through these inlets into the coastal ocean.