QDG = T i B (10)


where QDG is flow rate, i is gradient, T is transmissivity

(hydraulic conductivity multiplied by the depth of the

aquifer), and B is the width of the cross-sectional area

perpendicular to water flow. In calculations for this

model, B was the length of the coastline plus the length of

the Caloosahatchee River. As transmiss'ivities vary

somewhat in different parts of the study region, the total

length was divided into three stretches and a different

transmissivity was estimated for each, based on Klein et

al. (1964). T x B was determined for each stretch, and the

three values were added together to give a weighted T B for

the total river and coastline of the study region. In this

equation i was calculated by dividing elevation difference,

h, by distance, d. h is the variable, (12 + D), and D is a

variable less than or equal to 8 that represents how many

of the top 8 ft of the aquifer and soil are saturated. The

maximum volume of water in the soil-substrate compartment

was the saturation volume of the top 8 ft of the soil and

substrate, because average water levels for the entire area

never fall below 8 ft. Twelve ft plus a maximum of 8 ft is

the approximate average elevation of the water table

relative to sea level when the soil is saturated. At less

than saturation, the water table is lower and the gradient

between water table and the sea is less.