2006 Greater Everglades Ecosystem Restoration Conference

Hydrodynamic Modeling of the A.R.M. Loxahatchee National Wildlife Refuge

Ehab A. Meselhe 1, Alonso G. Griborio 1, Jeanne C. Arceneaux 1, and Michael G. Waldon 2

1 Center for Louisiana Inland Water Studies, University of Louisiana at Lafayette, Lafayette, LA, USA
2 Department of Interior Everglades Program Team U.S. Fish and Wildlife Services, Boynton Beach, FL, USA

This paper presents the development of a hydrodynamic and water quality model for the Arthur R. Marshall Loxahatchee National Wildlife Refuge. The Loxahatchee Refuge, which overlays Water Conservation Area-1, protects a last remnant of the historic northern Everglades in Palm Beach County, Florida. It covers 143,238 acres (about 58,000 ha) and is located seven miles west of the city of Boynton Beach. The Refuge is impacted by anthropogenic loads of nutrients and other contaminants, and changed hydroperiods. Water management must balance benefits of flood control, water supply, fish and wildlife protection, while minimizing the impacts of the excessive nutrient loading. The purpose of this modeling effort is to provide a quantitative framework for management decisions related to Refuge inflow and outflow quantity, timing, and quality.
A two-dimensional hydrodynamic model was set up for the Refuge using the unstructured finite volume model FVCOM. For this matter; an unstructured triangular mesh, consisting of 12,190 nodes and 22,848 elements, was generated using the MATISSE software. In this mesh, the smaller element sizes are about 15 meters (within and adjacent to the rim canal), and the larger element sizes are about 650 meters (on the central portion of the Refuge). This grid was refined at different locations, to allow for a good representation of the rim canal, and to capture the larger tree islands. Two-dimensional hydrodynamic simulations were performed forcing the model with the inflows and outflows from the hydraulic structures, and precipitation and evaporation as meteorological forcing. Also, an estimated seepage loss rate was included in the model. Using the period of record between 1995 and 2004, the model was used to predict spatial and temporal distribution of water inside the Refuge. The results show good agreement between observed and predicted stages at specific locations. In this respect, statistical analyses were conducted and confirm the accurate prediction of water levels by the model. Additionally, efforts are underway to model the transport of conservative tracer and the dynamics of total phosphorus in the Refuge. These results will be presented at the conference.

Contact Information: Alonso Griborio, Center for Louisiana Inland Water Studies, University of Louisiana at Lafayette, P.O. Box 42291, Lafayette, LA 70504-2347 USA, Phone: 337-482-0643, Fax: 337-482-0698, Email: agg2377@louisiana.edu