U.S Geological Survey, South Florida Ecosystem Program: Place-Based Studies

Project: Internal Surface-Water Flows

Web Site: http//sflwww.er.usgs.gov/projects/surf_wtr_flow/

Location: Southwest Coast / Big Cypress; Broward and Hendry Counties

Principal Investigator: Mitch Murray, mmurray@usgs.gov, 305.717.5827

Project Personnel: Rick Solis, rsolis@usgs.gov, 305.717.5848

Other Supporting Organizations: Seminole Indian Tribe of Florida, South Florida Water Management (SFWMD)

Associated Projects: SFWMD/Seminole Agreement Working Group (Linda Lindstrom, llindst@sfwmd.gov, 561.686.6820)

Overview & Status: Three sites have been gaged successfully for up to 4 years with one site discontinued at the end of the 1999 water year. The three Tribal Reservation sites (2 Seminole and 1 Miccosukee provide baseline discharge, stage, and flow weighted nutrient data prior to and after the implementation of the Stormwater Treatment Areas (STA) 5 and 6. Responsibilities for these sites are shared between USGS (avm/flow data collection, analysis, computations), Ocala Lab (nutrient analysis for 2 sites), SFWMD (telemetry/nutrient total load calculations), and Seminole and Miccosukee Tribes (nutrient data collection/lab analysis from Florida International University. The L28U site, located between the Seminole and Miccosukee Reservations, serves as one of the primary final data collection points used to monitor flow and TP contributions to WCA 3A, and as an exit and entry monitoring point from the Seminole to Miccosukee Reservations. Higher total phosphorus (TP) concentrations at the L28U compares to the upstream USSO site suggest that additional water with higher TP concentration than that of USSO water, enters the canal downstream of USSO. At L-29IN, new acoustic doppler current profiling (ADCP) instrumentation, and recalibration and recomputation has been done to correct data discrepancies. TP load analysis and subsequent load flow-weighted calculations by SFWMD from the L28IS site, located on the western boundaries of the Miccosukee Reservation, have been included in the fifth annual Semi-Annual Progress Report. This site was discontinued September 30, 1999 by the USGS and will be re-instrumented by the Miccosukee Tribe. STA’s 5 and 6 have been completed and close to a year of operational flow-weighted nutrient loads have now been collected. Experience from several velocity index alternatives tested by SFWMD at similar upstream gaging sites has been used to reconfigure a broad-crested weir as one of the products. Quality assurance has been, and continues to be, refined to better quantify mass balance. An AVM/flow-weighted auto-sampler protocol publication is proposed by SFWMD after results of new instrumentation are reviewed.

Needs & Products: The benefits of this project for the fiscal year and beyond are primarily twofold:
1) Retain a USGS presence in the C-139 basin to develop a deeper understanding of both water budget data collection issues as they relate to Storm Treatment Areas 5 and 6 and the associated water delivery modifications defined in the South Florida Water Management District/Seminole Tribe Agreement. This includes being able to compare upstream structure and weir flow discharge budgets against acoustic velocity index (AVM) flow discharge budgets using pre and post STA baseline data collection efforts. 2) Ongoing assessment of TMDL monitoring issues relating to acoustic flow weighting is a very topical concern. A very high potential exists to develop a separate nutrient load index using future insitu located doppler acoustics. With a slight future funding increase, this concept has the excellent potential to build inexpensively on the results of previous studies with a huge cost savings for Seminole Tribe/USGS funded nutrient collection and analysis which is an ongoing and integral part of the SFWMD/Seminole Agreement. If the concept is documented it has the desirable potential of either supplementing or expanding the existing nutrient monitoring network by obtaining a nutrient load index at existing and future velocity index sites throughout South Florida.

Application to Everglades Restoration: Flow and TP budget summaries will ultimately be used for the Central and Southern Florida Project Comprehensive Review Study, for compliance with federal and state permits and for the South Florida Water Management District/Seminole Tribe Agreement.