14 Appendix 3: The Water Supply Problem of the Everglades National Park*

National Academy of Sciences Advisory Committee on Research in the National Parks: The Robbins Report

Appendix 3: The Water Supply Problem of the Everglades National Park*

Introductory Statement

Southern Florida is a low-lying peninsula of prairie and swamp. Only a small portion of the area stands at an elevation above 25 feet, and the extreme southern part lies almost at sea level. Prior to 1900 it was almost uninhabited except by the Seminole Indians. That part known as the Everglades is the eastern half of the peninsula south of Lake Okeechobee. The Everglades Park, which was not established until 1947, lies south of latitude 25 45′ (which is about the latitude of Miami) and does not include the coastal strip about 25 miles wide, extending from Miami south to Key Largo. (see Plate I)


Prior to the drainage of the northern Everglades, the whole area was a vast solitude of saw grass and water with “hammocks” of trees, various slough areas and higher ridges of pine land. Along the south and west coasts were extensive forests of mangroves. The rainfall is heavy, averaging about 57 inches per year, but the rains come almost entirely in the summer months, leaving the winter and spring very dry. There is a great variation in the amount of annual precipitation.

Prior to the digging of drainage ditches, the area now occupied by the Park, received a large amount of water flowing slowly down from the north, and during the summer most of the area was covered with water. The Kissimmee River which flows southward from Central Florida, drains a large area south of Orlando, and discharges into Lake Okeechobee. In its natural state, the lake had no well-defined outlet. Before the digging of the canals, the lake would fill to overflowing in the summer months and the water would flow over its banks, and spill slowly through the swampy areas and sloughs, moving generally outward to the tip of the Peninsula.

Hurricanes caused heavy flooding. The hurricane of 1928 during which there was a wind velocity of 150 miles per hour, caused a “tidal wave” on the lake 13 feet high, which flowed over the land to the south and drowned hundreds of people. Following this catastrophe, the Federal Government undertook an extensive flood control project to drain away the flood waters from the rich agricultural land south of the lake.

However beneficial the drainage was to the agricultural community, there were many side effects. Gerald Parker of the U.S. Geological Survey wrote: [1]

“It is doubtful that the drainage enthusiasts ever envisioned that, among other results of their operations, they would induce or cause:

  1. Shrinkage, compaction, oxidation, burning and general subsidence of the organic soils . . . as much as 5 feet over extensive cultivated areas.
  2. Development of wide shallow “subsidence valleys” along each drainage canal.
  3. Increase frost damage, which formerly had been held in check in the muck and peat soils by the ever present water which gave off heat as it froze. (Parker wrote this before the winter of 1962-3 when the loss by freezing of vegetable crops was enormous. Note by author of this paper.)
  4. Reduce the original capacity of the canals, thus contributing to flooding.
  5. Cessation of the processes that had built up the muck and peat in the first place.
  6. Changed ecologic conditions seriously affecting wildlife of the drained areas, resulting in species migration or near extinction.

Water problems have become of prime importance. Whereas we in this area were first concerned only with getting rid of water, or practicing flood control, we now are greatly concerned (with effects caused by inadequacy of water).”

It is not possible to state accurately how much water formerly flowed into and through the area now occupied by the Park. A publication dated May 22, 1950, by the Flood Control District, as quoted by Lamar Johnson of Lake Worth in a report which he wrote in July, 1958, entitled, “A Survey of the Water Resources of Everglades National Park,” page 7, is as follows:

“The estimated discharge along the 40-mile front at the present location of Tamiami Trail during the pre-drainage period, was:

“Average rainfall year – 2,315,000 acre feet
Dry rainfall year – Negligible
Wet rainfall year – 10,744,000 acre feet”

An acre foot is approximately 325,800 gallons.