Strategic Assessment of Florida's Environment (SAFE)

Use of Saline Ground Water as a Source of Public Supply

Explanation of Indicator


The state of Florida depends on its ground water resources for drinking water, for agriculture, for industry, and in some cases as a water source for surface water habitats. Unfortunately, nearly all human activities may adversely affect Florida's ground water quality and quantity. The state is expected to grow at a rate of three percent annually, with most of the growth along coastal areas where water resources are already being threatened by over-consumption, contamination, and saltwater intrusion.

Salt water intrusion in coastal communities required the blending of water from differing sources, some with high salinity, to produce water which meets the chloride content standard for human consumption (250 mg/l).a Salt water intrusion is evident in certain areas of Florida and water which exceeds 1,000 mg/l dissolved solids content has significantly increased. In the five year period between 1980 and 1985, the use of saline ground water increased from 2.5 million gallons per day to 17.3 million gallons per day.

Technology advances have rendered the reverse osmosis desalination process an economically feasible alternative to bolster dwindling supplies. Continued population concentrations in the coastal areas, increased ground water withdrawals to meet population demands, and the incidence of periodic drought conditions should cause an increase in the use of saline supplies. This increase will provide an indication of the pressures placed on a limited resource as well as our limited capabilities to reverse the process.

Source


The U.S. Geological Survey (USGS) provides periodic updates of its documents which deal with water withdrawals, use, and trends in Florida. Data for the USGS reports come from the water management district consumptive use permit files and the Florida Department of Environmental Protection monthly operating reports.

Data Characteristics


This information is collected statewide throughout the year by both the Department and the water management districts, but is compiled about every two years. Hard copy reports are provided by USGS to the Department library. For copies of the USGS reports contact USGS, WRD - Florida District, 227 North Bronough Street, Suite 3015, Tallahassee, Florida 32301 or U.S. Geological Survey, Books and Open-File Reports, Section, Federal Center, Building 810, Post Office Box 15424, Denver, Colorado 80225. There is no additional costs to acquire this data.

Overall Assessment


Although the public water supply data in the USGS report represents a sample of suppliers of public water, those who serve 400 or more people, it provides an accurate measure of water use trends in the State which can be utilized to analyze the effects of current water use policy and provide a basis for discussion of change. The total amount of public supply water used is estimated from this sample.b For example, the 1985 data was the result of an inventory of water usage supplied by 633 public and private utilities, which represents the majority of the total public water systems. The author felt that this data was the most reliable data in the report.

Analysis of Indicator


Prior to 1970 the use of saline water was not measured. However, in 1985 the use of saline ground water as a source of public supply was 17.28 million gallons per day (MGD). When next reported in 1987, saline ground water utilization more than doubled to 37.4 MGD. The 20.12 MGD increase over the two year period represented a 116 percent increase. In 1990, about 47.96 MGD of saline ground water was utilized as a source of public water supply. This represents a 28 percent increase since 1987 and a 178 percent increase since 1985.


                   Use of Saline Ground Water
                  as a Source of Public Supply

_______________________________
a Chapter 17-550.320, Florida Administrative Code.

b Pursuant to Chapter 17-550, Florida Administrative Code, the definition of a public water system is, "... a system that provides piped water to the public for human consumption, if it has at least fifteen service connections or regularly serves at least twenty-five individuals daily at least 60 days out of the year."