Home Biscayne aquifer Hydrologic system Water quality Ground-water withdrawal Vulnerability of Biscayne aquifer Future problems of potable supplies Other drinking water sources Summary & References PDF Version

In 1976 eighteen major utility companies operated 37 well fields and water-treatment plants in Dade County to supply about 345 million gallons on peak-demand days. In Broward County 49 major facilities (fig. 18) supplied nearly 155 million gallons per day. The average daily pumpage by the municipal system in Boca Raton was 17 million gallons in 1976. Figure 19 shows the areas in Dade and Broward Counties that are served by municipal or small public water-supply systems and those areas served by individual residential private wells (Planning Departments, Broward and Dade counties). Almost 84 percent of the developed area of Dade County is served by public water systems.

Figure 19. -- Areas of public water-supply systems under franchise in Broward County and in service in Dade County, 1977 (Broward County Land Use Plan, 1977, p. 107; Metropolitan Dade County Master Plan, 1977, p. 52). [larger image]

In 1975 a total of 62,350 acres were irrigated in Dade and Broward counties with an average for the year of 168 Mgal/d of canal and ground water. Wells produced 67 percent of the total. Water use is seasonal.

Most agricultural land in the area of the Biscayne aquifer is east of the water-conservation areas of the SFWMD but west of the urban coastal zone. Truck crops are the main produce. Irrigation and fertilization are required during the fall and winter. In recent years, new methods of planting under plastic sheets have reduced the requirements for irrigation water, fertilizer, and pesticides. Citrus, mango and avocado groves, are scattered along the coastal areas, to the west in south Dade County, and in inland parts of south Broward County. These groves require irrigation primarily during November through May. Most of the grove irrigation is by overhead sprinkling.

Water levels are highest in the water-conservation areas and ground-water flow is generally toward the coast (figs. 7 and 8). Locally, flow direction may be influenced by canals and by pumping wells.

The direction of ground-water flow in the vicinity of the large municipal well fields is greatly influenced by continuous heavy withdrawals. The effects on water levels and ground-water flow in two of the large well fields are shown in figures 20 and 21. The water levels in the Hialeah-Miami Springs well field, in 1974, were lowered to 8 ft below sea level at the center of pumping (fig. 20), and ground-water flow was toward that center from the surrounding areas. The withdrawal rate in 1.974 was 110 Mgal/d. Water from the adjacent Miami Canal and other local canals was leaking downward into the aquifer. An auxiliary well field is being established 0.5 mi west of the junction of the Miami Canal and the Florida East Coast Canal. It is designed to reduce the rate of withdrawal from wells in the south part of the municipal well field near the Miami International Airport, an area threatened by saltwater intrusion during the dry seasons.

The contours in fig. 21 show the effect on ground-water levels caused by withdrawal of 30 Mgal/d from the Fiveash well field of the city of Fort Lauderdale in May 1972. Water from Canals 13 and 14 was being diverted toward the center of pumping.

Figure 20. -- Water levels and directions of ground-water flow in the Hialeah-Miami Springs well fields area, October 8, 1974 (from Hull and others, 1975). [larger image]	Figure 21. -- Water levels and directions of ground-water flow in the Fort Lauderdale Fiveash well field area, May 1972 (from Klein and others, 1975, p. 106). [larger image]

Go back to Water quality | Go ahead to Vulnerability of Biscayne aquifer to contamination