From July 1972 to June 1973, 78 percent (5200 metric tons or 5,700 tons) of the total nitrogen and 90 percent (207 metric tons or 228 tons) of the total phosphorus entering the conservation areas was contributed by bulk precipitation (rainfall and dry fallout). Controlled and noncontrolled surface-water discharge contributed the remainder: 22 percent (1,460 metric tons or 1,610 tons) of total nitrogen and 10 percent (22.4 metric tons or 24.7 tons) of total phosphorus. Of the water lost, 53 percent was by seepage and 47 percent by surface water discharge, of which 11 percent flowed eastward and 89 percent southward to Everglades National Park. Most surface-water loads of total nitrogen (90 percent, 696 metric tons or 767 tons) and total phosphorus (88 percent, 5.2 metric tons or 5.7 tons) leaving the conservation areas entered Everglades National Park. About 5,000 metric tons (5,500 tons) of total nitrogen and nearly 220 metric tons (242 tons) of total phosphorus were apparently retained within the conservation areas. This retention constitutes 74 percent of the total nitrogen and 96 percent of the total phosphorus that entered the conservation areas from July 1972 to June 1973.
