Effects of bottom sediments on infiltration from the Miami and tributary canals to the Biscayne aquifer Dade County, Florida

Infiltration from the Miami Canal and its tributaries is an important source of recharge to the Biscayne aquifer in the vicinity of the Miami Springs-Hialeah well fields. Estimates of pumpage contributed by canal infiltration decreased from nearly 100 percent in the late 1940 's to 50 percent in May 1973 while well field pumpage increased from less than 50 Mgal/d to 120 Mgal/d. As increased withdrawals enlarge the well field 's cone of depression, the threat of saltwater intrusion during dry periods has been increased. Data on water quality, water levels, and canal bottom sediments indicate that sediments greatly impede infiltration from the canals in the areas most affected by pumping. Bottom sediments reduce coliform bacteria, pesticides, PCB, metals, and other suspended materials infiltrating canal water.