Caribbean-Florida Water Science Center
Description of the Lake Wales Ridge Study Area
The Lake Wales Ridge study area encompasses about 700 square miles in Polk and Highlands Counties and includes one of the most productive citrus regions in Florida. Citrus is one of the top agricultural crops in Florida (excluding pastureland), accounting for about 75 percent of the nationís citrus production, and generating over $1.6 billion of revenue in Florida annually. Nearly 40% of Floridaís citrus acreage occurs on the sandy soils (Entisols) along the central Florida ridge systems. The most prominent of these ridge systems is the Lake Wales Ridge. Citrus land use covers about 25 percent of the study area. Polk and Highlands Counties have been among the top three citrus-producing counties statewide in Florida in recent years.
The Ridge was selected for study because it is highly vulnerable to leaching of chemicals such as pesticides and fertilizers. The sandy soils on the Ridge are well drained and contain little organic matter to adsorb, or effectively filter out, organic compounds. The long growing season in Florida necessitates multiple applications of fertilizers and pesticides, thereby increasing the potential for leaching of these chemicals compared to many locations in the United States. Seasonally high rainfall amounts and intensities in this region increase the potential for transport of contaminants into the subsurface. Groundwater is the principal source of water supply on Lake Wales Ridge, typical of most regions in Florida. Furthermore, the groundwater system in the surficial (water table) aquifer is closely linked with the numerous lakes in the region and is hydraulically connected with the underlying Upper Floridan aquifer, the primary municipal water supply for the region.
Split-spoon sample during drilling of monitoring wells typifies the uniformity of the sandy deposits on the Ridge. - click to enlarge
Lake Wales Ridge has been the focus of a number of efforts to minimize potential impacts of citrus agriculture on water resources. Citrus growers and industry representatives, the University of Florida Institute of Food and Agricultural Science (IFAS), and several state and federal agencies have partnered in related research and monitoring in this region. Results of this work have included the formation of collaborative industry-science working groups, as well as development of guidelines and regulations for application of specific agrichemicals to minimize potential transport into the subsurface, including the adoption of fertilizer best management practices developed specifically for Ridge citrus (State of Florida, 2002, Statute Title XXXV).