groundwater flow to sea. Surface water runoff occurs only

when that volume is exceeded which is required to fill all

surface water areas to the estimated lowest points on their

rims. Only the top 5 ft (1.5 m) of soil-substrate water is

available to the roots of most plants and thereby subject

to removal by transpiration. Evapotranspiration from

surface water cannot remove a greater quantity of surface

water than is present. Rainfall is accepted by the soil-

substrate water tank only to the capacity of saturation

volume of the tank. Upland rainfall in excess of the

saturation volume of the soil-substrate tank becomes a part

of the surface water.

 The water model was simulated on an IBM 370 digital

computer at the Northeastern Regional Data Center of the

University of Florida, using the DYNAMO modeling package.





 Analyses of Rainfall



Trend Analysis

 Moving 5-yr averages of annual, total wet season, and

total dry season rainfall for the 25-yr period of record at

Corkscrew grove (ALICO, pers. comm.) were graphed.

Graphing moving averages eliminates short term variation in

a periodic or noisy record so longer term periodicity or

trends, if present, can be identified. The 5-yr grouping

for the moving average was selected because Thomas (1970)