Water Budget Model for a Remnant of the Historic Northern Everglades

Arceneaux, J C, jca1666@louisiana.edu, University of Louisiana at Lafayette - Center for Inland Water Studies, P.O. Box 42347, Lafayette, LA 70504 United States
Meselhe, E A, meselhe@louisiana.edu, University of Louisiana at Lafayette - Center for Inland Water Studies, P.O. Box 42347, Lafayette, LA 70504 United States
Habib, E habib@louisiana.eduUniversity of Louisiana at Lafayette - Center for Inland Water Studies, P.O. Box 42347, Lafayette, LA 70504 United States 
Waldon, M G, mike@mwaldon.comU.S. Fish and Wildlife Services - Arthur R. Marshall Loxahatchee National Wildlife Services, 647 Cajundome Blvd., Ste 400, Lafayette, LA 70506 United States

The Arthur R. Marshall Loxahatchee National Wildlife Refuge overlays an area termed Water Conservation Area 1 (WCA-1), a 143,000 acre (58,000 ha) freshwater wetland. It is a remnant of the northern Everglades in Palm Beach County, Florida, USA. Sheetflow that naturally would flow across the Refuge wetlands was disrupted in the 1950s and early 1960s by construction of stormwater pumps, and levees with associated borrow canals which hydraulically isolated the Refuge from its watershed. The U.S. Fish and Wildlife Services (USFWS) concludes that changes in the water quantity, timing, and quality have caused negative impacts to the Refuge ecosystem. It is a top priority of the Refuge to ensure appropriate management that will produce maximum benefits for fish and wildlife, while meeting flood control and water supply needs. Models can improve our understanding and support improvement in these management decisions. The development of a water budget for the Loxahatchee Refuge will provide one useful modeling tool in support of Refuge water management decisions. The water budget model reported here was developed as a double- box (2-compartment) model with a daily time step that predicts temporal variations of water level in the Refuge rim canal and interior marsh based on observed inflows, outflows, precipitation, and evapotranspiration. The water budget model was implemented using Microsoft EXCEL. The model calibration period was from January 1, 1995 to December 31, 1999; the validation period extended from January 1, 2000 to December 31, 2004. Statistical analyses demonstrate the utility of this simple water budget model to predict the temporal variation of water levels in both the Refuge marsh and rim canal. The Refuge water budget model is currently being applied to evaluate various water management scenarios for the Refuge. Preliminary results modeling the mass balance of water quality constituents, including chloride, total phosphorus are encouraging. Success of this model may be transferable to other wetland systems where overbank flooding is a dominant mechanism affecting hydrology and water quality within the wetland.

AGU 2006 Fall Meeting, San Francisco, CA, 11-15 December 2006