Mark Zucker¹, Jeff Woods¹, and Carrie L Boudreau¹

¹U.S. Geological Survey, Florida Integrated Science Center, Ft. Lauderdale, FL 33315; PH (954) 377-5952; email: mzucker@usgs.gov

Data collection at Card Sound Canal began in October 2003 as part of the Coastal Gradients of Flow, Salinity, and Nutrients Project funded by the U.S. Army Corps. of Engineers, Comprehensive Everglades Restoration Plan (CERP). An evaluation of the field data indicated the potential for data bias due to routinely observed bi-directional flow and salinity/temperature stratification. Because of the unique hydrologic conditions at this site, new methods were employed to collect representative, high quality data.

To improve the computation of discharge and eliminate bias due to bi-directional flow, a side-looking acoustic Doppler velocity meter (ADVM) was replaced with an up-looking ADVM that was mounted on the creek bottom. The salinity and temperature stratification issue was resolved by installing a floating probe at the surface of the water column and by mounting a second probe below the observed thermocline at the bottom of the stream. Automatic samplers are routinely deployed to collect point samples. At Card Sound Canal, two sampling intakes were deployed in a vertical configuration similar to that of the salinity/temperature probes in order to collect a more representative sample from the stratified canal. Cross sectional water samples were collected quarterly, and a good comparison was noted between the automatic sampler results and the integrated sample results. The implementation of these field methods was critical for the eventual computation of nutrient loading at this site.

(This abstract is from the November 5-9, 2007 USGS National Water-Quality Workshop.)

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