Project Summary Sheet

Project: Internal Surface-Water Flows

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

Location (Subregions & Counties): Southwest Coast / Big Cypress; Broward and Hendry Counties

Funding (Source): Seminole Tribe of Florida, USGS Place-Based Studies

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

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

Supporting Organizations: Seminole Indian Tribe of Florida, South Florida Water Management (SFWMD), U.S.Geological Survey

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

Overview & Status: Three sites have been gaged with acoustic flow sensors and flow-weighted nutrient auto-samplers successfully for up to 6 years with one site (L-28IS) discontinued at the end of the 1999 water year. From their inception in 1996, these three Tribal Reservation sites (2 Seminole and 1 Miccosukee) have provided baseline discharge, stage, and flow weighted nutrient load data prior to and after the implementation of the upstream Storm Water Treatment Areas (STA) 5 and 6. Responsibilities for these sites are coordinated and shared between USGS staff (flow data collection, analysis, computations), the USGS Ocala Lab (nutrient analysis for 2 sites), SFWMD (telemetry/nutrient total load calculations for all sites), and Seminole and Miccosukee Tribes (nutrient data collection/lab analysis and flow funding). The now discontinued L28IS site, previously located on the western Miccosukee Reservation border, served as one of the primary final data collection points used to monitor flow and TP contributions to Water Conservation Area (WCA) 3A and also as a flow and load budgeting verification point for the upstream Seminole Reservation site, L-28IN.

A new acoustic side-looking Doppler velocity indexing system was installed at the L-28 IN site (L-28 Interceptor Canal), and data collected in tandem with the existing AVM velocity indexing system for the six month period which followed. This test along with an Acoustic Doppler Current Profiling (ADCP) calibration effort produced a new flow-rating resulting in a much more accurate and reliable total and instantaneous flow computation. Quality assurance has been, and continues to be, refined to better quantify mass balance for flows and nutrients to both reservations and WCA 3A.

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 Tribal Agreement. 2) Ongoing assessment of TMDL monitoring issues relating to acoustic flow weighting is a very topical concern. The support of this project has produced a side-looking Doppler flow-weighted velocity index that is the first such system in South Florida.