FYI, Though you all might be interested. Sorry for the short notice. Todd will also be making the presentation to the UT Grotto on Wednesday evening on Mapping and Modeling Underwater Caves & Application to Groundwater Management.
Thanks, Geary Edwards Aquifer Philosophical Society - Wednesday, February 16, 2011 (3:30 PM) Edwards Aquifer Authority Conference Room 1615 N. St. Mary's Street, San Antonio, TX We are pleased to announce that Dr. Todd Kincaid, will be making a presentation titled: Demonstrating interconnection between a wastewater application and a first magnitude spring in a karstic watershed: Tracer stdy of the Tallahassee, Florida Treated Effluent Spray Field 2006-2007. The presentation will be held on Wednesday, February 16, 2011 at 3:30 PM to 4:30 PM in the conference room at the Edwards Aquifer Authority. For directions or further information, the Authority may be contacted at 210.222.2204 or www.edwardsaquifer.org<http://www.edwardsaquifer.org/> If you are traveling a long distance to the talk, I would recommend that you call our receptionist that morning to make sure that the talk is still scheduled at the number below. On very rare occasions, we have had to cancel or move the talk. I apologize for any inconvenience this may cause. Thank you. Geary Schindel Chief Technical Officer Edwards Aquifer Authority 210.222.2204 Demonstrating interconnection between a wastewater application facility and a first magnitude spring in a karstic watershed: Tracer study of the Tallahassee, Florida Treated Effluent Spray field 2006-2007 The City of Tallahassee's SE Spray Field (SESF) receives secondarily treated wastewater and disperses it onto the land surface via center-pivot irrigators at an average rate of approximately 17 million gallons per day (City of Tallahassee, 2007). The system is intended to provide nutrient removal through plant uptake from the infiltrating water. It became operational in 1981, encompassing 1000 acres and was expanded in 1982 to 1500 acres, 1986 to 1896 acres, and 1999 to 2,159 acres (Chelette et al, 2002). Nitrate levels in groundwater monitoring wells installed in the upper Floridan aquifer beneath the SESF increased precipitously after the SESF became operational rising from ~0.5 mg/L in 1980 to as much as 10 mg/L in the 1990's and stabilizing at ~6 mg/L by 2000 (Chelette et al, 2002). During the same period, nitrate levels measured at Wakulla Spring rose from ~0.2-0.3 mg/L between 1971 and 1976, to >1.0 mg/L in the late 1980's, to ~0.7-0.8 mg/L between 1998 and 2000 (Chelette et al, 2002). The increased nitrate levels are thought to be the primary cause of algae growth and enhanced hydrilla growth that have resulted in significant harm to the ecosystems supported by Wakulla Spring and the Wakulla River (Hand, 2005). Given the apparent correlation between nitrate increases in Wakulla Spring and in Floridan aquifer groundwater beneath the SESF, considerable attention became focused on the SESF as the primary source of nitrate contamination to the spring by 2000. Further attention was directed toward the SESF when Chelette and others (2002) reported nutrient budget calculations for the St Marks and Wakulla River Watersheds that attributed 40% of the nitrate loading in the Wakulla Springs contributory area to the SESF. In response to growing concerns about the fate of nitrates released to the Floridan aquifer from the SESF, the City of Tallahassee approved a 3-year study with the US Geological Survey to, in part, develop of model of nitrate transport through the upper Floridan aquifer. In concert with that effort, the Florida Department of Environmental Protection and the Florida Geological Survey commissioned Hazlett-Kincaid, Inc. to perform a groundwater tracing study to identify potential groundwater flow paths and velocities between the SESF and down-gradient springs. Tracer injections were performed in three wells across the northern side of the SESF and one sinking stream located on the southeastern side of the property. Water samples were subsequently collected from ten wells and eleven natural discharge points for between two and fourteen months and analyzed in a laboratory for the presence and relative amount of the injected tracers. Sampling for the fluorescent dyes was also conducted at two of the wells, Wakulla B-Tunnel, and the St. Marks River upstream of its disappearance with insitu filter fluorometers (IFF). One or more of the Fluorescent dyes was detected at five of the wells and five of the springs. The springs at which the fluorescent dyes were detected include: Wakulla Spring, Sally Ward Spring, Indian Spring, and one or more of the small springs contributing to flow in McBride's Slough. The fastest travel times to those springs established by fluorescent tracer breakthrough curves ranged from approximately 28-66 days after the injections with subsequent smaller pulses of tracer-laden water arriving at Wakulla and McBride's Slough as late as approximately one year after the injections. Very minor quantities of fluorescent compounds that fluoresce in the same range as the injected tracers were detected at Monroe Spring and the St. Marks River Rise but not enough to be confident that our tracers were recovered at those locations. None of the fluorescent tracers were detected at in the St. Marks River at Natural Bridge, Rhodes Spring, or Newport Spring. Biography Todd began cave diving in 1987 after eight years of diving in many of Florida's spring basins. He went on to explore and map several underwater caves in Florida, Turkey, Mexico, and China and study the role of caves in controlling groundwater flow patterns for M.S. and Ph.D. degrees from the University of Florida and the University of Wyoming. Since leaving school, he has been working with a team of researchers and explorers with the Florida Geological Survey and the Woodville Karst Plain Project to understand karstic groundwater flow to Wakulla Spring in North Florida. That work has included detailed underwater cave mapping, quantitative groundwater tracing, hydraulic metering of discrete cave passages, and the numerical simulation of conduit/matrix groundwater flow to delineate springshed boundaries, travel-times, and the impact of gradient reduction on spring flows driven by groundwater pumping and sea-level rise. He leads a small consulting company, GeoHydros, that specializes in geological and groundwater modeling. He serves as vice-president of Global Underwater Explorers, a non-profit organization dedicated to the exploration and conservation of underwater environs and the education of divers aimed at fostering those goals. He also serves on the Advisory Board for the Hydrogeology Consortium and the Florida Springs Institute, both non-profit organizations dedicated to the protection of Florida's springs. When he's not working, he enjoys all manners of outdoor exploration with his wife Kristie and little girl Ginnie. Geary M. Schindel, P.G. Chief Technical Officer EDWARDS AQUIFER A U T H O R I T Y 1615 N. ST. MARY'S STREET SAN ANTONIO, TX 78215 (210) 222.2204 OFFICE (210) 299.5262 FAX (210) 326.1576 MOBILE
