Water and Land Uses:
Municipal Withdrawls

Ground water is the principal source of water for municipal supply and the sole source of drinking water for about 3.8 million people in southeastern Florida. West Palm Beach is the only major municipality in southeastern Florida that uses surface water (obtained from nearby lakes) as its principal supply. In West Palm Beach, surface-water use increased from about 4 Mgal/d in 1930 to about 25 Mgal/d in 1995. Near Lake Okeechobee, several small rural communities use surface water for municipal supply.

Municipal withdrawals in Broward, Miami-Dade, and Palm Beach Counties have increased more than 11 fold over 65 years (figs. 18-20), from about 70 Mgal/d in 1930 to about 790 Mgal/d in 1995 (table 1). Increased withdrawals from the surficial aquifer system have combined with substantial land-use changes to affect the balance between freshwater and saltwater in the ground-water flow system. In 1930, only three municipal well fields operated in southeastern Florida, withdrawing about 66 Mgal/d (fig. 18); surface water supplied about 4 Mgal/d to West Palm Beach. By 1965, withdrawals from 41 well fields in the tri-county area exceeded 348 Mgal/d (fig. 19). Thirty years later (1995), 68 well fields withdrew about 790 Mgal/d (fig. 20). By 2020, municipal water demands are projected to reach 1,200 Mgal/d and serve 6 million people (South Florida Water Management District, 2000, p. 3).

Table 1. Municipal water use in Miami-Dade, Broward, and Palm Beach Counties from 1930 to 1995 [Click on image for entire table (#1)]

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The expansion of existing well fields and development of new municipal supply well fields have paralleled urban development. Temporal and spatial analyses of well-field locations and withdrawals during the 20th century illustrate a westward shift in construction away from the coast in an effort to mitigate saltwater intrusion (figs. 18-20 and table 1). Recommendations are outlined in the Comprehensive Everglades Restoration Plan (U.S. Army Corps of Engineers and South Florida Water Management District, 1999) to further shift large well-field withdrawals from the coastal areas to western facilities. The relocation of existing or construction of new municipal well fields in western urban areas, however, is tempered by concern that they may adversely affect Everglades and water-conservation area ecosystems.

Figure 18. Municipal ground-water withdrawals in Miami-Dade, Broward, and Palm Beach Counties in 1930, 1940, and 1950. Derived from the files of the U.S. Geological Survey. [larger image]

 

Figure 19. Municipal ground-water withdrawals in Miami-Dade, Broward, and Palm Beach Counties in 1965, 1970, and 1980. Derived from the files of the U.S. Geological Survey. [larger image]

 

Figure 20. Municipal ground-water withdrawals in Miami-Dade, Broward, and Palm Beach Counties in 1985, 1990, and 1995. Derived from files of the U.S. Geological Survey. [larger image]

Centralized and decentralized well-field infrastructure development is evident in figures 18 to 20. In Miami-Dade County, a few large-capacity well fields withdraw the bulk of the municipal supply. Although 1995 ground-water withdrawals in Miami-Dade County were estimated to be about 394 Mgal/d, only 14 well fields were operational (table 1). Five of these well fields withdrew more than 344 Mgal/d in 1995, which accounted for about 87 percent of all county withdrawals.

Municipalities of eastern Broward and Palm Beach Counties employ a decentralized system, illustrated by a wide distribution and numerous well fields withdrawing less than 10 Mgal/d (figs. 18-20). To help meet local supply needs, most of these municipalities developed their own water utilities and well fields. As municipalities became established and local populations grew, new well fields were constructed. In 1995, 30 and 26 well fields were operational in Broward and Palm Beach Counties, respectively (table 1). Only the Fort Lauderdale Well Field (combination of the Dixie and Prospect Well Fields) in Broward County withdrew more than 20 Mgal/d of ground water. The Boca Raton Well Field in Palm Beach County withdrew more than 35 Mgal/d of ground water; however, the remaining well fields in the county withdrew less than 13 Mgal/d of ground water.

The Miami-Hialeah (Hialeah-Miami Springs), Northwest, and Alexander Orr, Southwest, and Preston (Snapper Creek) Well Fields in northeastern and east-central Miami-Dade County (fig. 20) are among the largest and most productive well fields in Florida. In 1995, these five well fields withdrew more than 125,000 Mgal (about 343 Mgal/d) of ground water from the surficial aquifer system, accounting for about 87 percent of all the county well withdrawals. Despite historic problems associated with saltwater intrusion (Klein and Ratzlaff, 1989), the Miami-Hialeah Well Field has consistently served as a major source of water in southern Florida since its construction. About 162 Mgal/d of ground water were withdrawn from the Hialeah-Miami Springs Well Field in 1980. Well-field withdrawals diminished considerably (about 69 Mgal/d) in 1985 due to low-grade toxic contamination reported in some supply wells; consequently, production was increased from the Northwest Well Field. In 1995, withdrawal rates from the Miami-Hialeah Well Field subsequently increased to about 123 Mgal/d (table 1). Smaller well fields located in southern Miami-Dade County serve the needs of Homestead, Florida City, and the Everglades. Miami-Dade County also has exported ground-water supplies to the Florida Keys in Monroe County (Marella, 1999).

Saltwater intrusion has been a concern or has been detected near coastal well fields in Broward County, including Deerfield Beach, Hallandale, Pompano Beach, and the Davie Well Fields and has resulted in some local reduction or curtailment of production in selective wells. Additionally, saltwater contamination incidents have been of concern due their proximity to a number of well fields in Broward County including Fort Lauderdale (Dixie and Prospect), Broward County 2A and 3A, Plantation, and Sunrise.

Saltwater intrusion has been a concern near the Boca Raton Well Field in coastal southern Palm Beach County. Well fields have been constructed inland, and production along the coast has been reduced.