HR: 1340h
AN: H53A-1192    [Abstracts]
TI: Groundwater Nutrient Flux Meter Application for Determination of Phosphorus Flux: Application in Lake Okeechobee Basin, FL
AU: * Hamilton, M K
EM: khammi@ufl.edu
AF: Soils and Water Science, 2169 MCCarty Hall PO Box 110290, Gainesville, FL 32611 United States
AU: Cho, J
EM: jaehyunc@ufl.edu
AF: Environmental Engineering, 353 NEB P.O. Box 116450, Gainesville, FL 32611 United States
AU: Jawitz, J W
EM: jawitz@ufl.edu
AF: Soils and Water Science, 2169 MCCarty Hall PO Box 110290, Gainesville, FL 32611 United States
AU: Annable, M D
EM: annable@ufl.edu
AF: Environmental Engineering, 353 NEB P.O. Box 116450, Gainesville, FL 32611 United States
AU: Hatfield, K
EM: khatf@ufl.edu
AF: Civil Engineering, 580 WEIL HALL PO BOX 116580, Gainesville, FL 32611 United States
AB: As part of a larger study of phosphorus (P) movement within cow-calf agricultural systems, nutrient flux meters (NFM's) were deployed around several isolated wetlands to monitor and determine P flux. Phosphorus loading is a recurring problem in agricultural systems as excess phosphorus concentrations drive P-limited systems to a eutrophic state. The (NFM) is a cylindrical, permeable unit of variable length containing a sorbent that fits tightly into a well casing and was designed to use a variety of sorbents depending on application. A strongly basic anion exchange resin was used to retain phosphate present in groundwater while a separate sorbent was used to hold a tracer to determine water flux. Lab experiments were conducted for the selection of an appropriate sorbent that was suited for low concentrations of P and other parameters. The NFM was deployed in several monitoring wells to determine the mass flux of P present in the groundwater resulting from cow-calf operations at the Larson Ranch in Okeechobee, Florida. Several NFM's were deployed in groundwater monitoring wells surrounding the isolated wetlands and in the artificial drain from the wetlands. Phosphorus fluxes were determined by extraction from the anion exchange resin. From the deployment of the NFM for a pre-determined amount of time, P mass flux was found to be higher in the wells that were upgradient of the wetland and reduced at the exit point. Groundwater flux was also determined to be toward the wetland based on the observed gradients. The NFM is a useful tool for measuring groundwater nutrient movement in groundwater around wetlands and in general for TMDL applications.
DE: 1829 Groundwater hydrology
DE: 1831 Groundwater quality
DE: 1832 Groundwater transport
SC: Hydrology [H]
MN: 2004 AGU Fall Meeting