Canal Sediment Physicochemical Characteristics and Potential for P Release In South Florida.

Excess nutrients such as phosphorus (P) transported from the Everglades Agricultural Area (EAA) with drainage water to downstream water bodies has been identified as the primary cause of trophic imbalances within the Florida Everglades. The organic soils of the EAA are drained by pumps and extensive array of canals. Decades of farming activity has loaded the regional canals with P, rendering the sediments as a potential internal source of P to the system. In this study we analyzed sediments from three canals to determine the physicochemical characteristics and potential for P release. Total P released from the Miami canal during three flood water exchanges was higher than P released from West Palm Beach and Ocean canals. The P release also varied spatially within each canal. Phosphorus released into the water column was positively correlated with total P, Fe and Al oxide content in the sediments. Estimated total internal P loads from all canals calculated in this study is a very small percentage of the total loads from the EAA basin. But this estimated load does not take into account the impact of sediment transport and resuspension on water column P.