SOME FLORIDA LAKES AND LAKE BASINS.

The total solids removed in solution of central Florida, expressed in tabular results :*

Name of Spring County.
Blue ................... M arion
Blue ................... Levy
Ichetucknee............. Columbia
Newland..............Suwannee
Weekiwachee ........... Hernando
White Sulphur..........Hamilton Suwannee ..............Suwannee

through six other springs form, gives the following

Total solids Est. flow
(parts per (gals. per
million) min.)
112.1 349.166
196.8 25,000
211.6 i8o,ooo
233.5 75,000
227.8 100,000
166.6 32,400
332.7 19,747

Solids removed lbs. per day.
469,698 59,040 457,050 210,150
273,360
64,774 78,816

As the basis of an estimate of the total solids removed annually from the interior, let it be assumed, (i) that the average total solids in spring water amount to as much as 219 parts per million, this average being obtained from eight of the typical large springs of central Florida; (2) that the annual escape of the undergroun( water approximates the annual in-take, amounting, as previously estimated to 46o,536,689 gallons per square mile. Upon these estimates the mineral solids removed amount to a little more than four hundred tons annually per square mile.
Of the minerals thus removed, calcium carbonate or limestone greatly predominates, exceeding the combined weight of all other minerals. From the analyses it appears that magnesium carbonate, magnesium and calcium sulphates are present in variable, although usually limited, quantities. Chlorides are normally present in small amount, although occasionally, as in the case of Perrian Spring, they are exceptionally high. Silica is present in amounts varying from 5 to 25.5 parts per million. Traces of phosphoric acid and of iron and alumina are usually present.
The several undetermined factors which enter into the above estimates of mineral solids removed make it difficult to formulate a concrete statement of the rate of lowering of the general surface level. Nevertheless, such statements are desired and have a comparative value. Assuming for the rock removed, most of which is
*For 340 in the second line from the bottom on the preceding page read 84o.
tOrganic matter is deducted from the total solids as given for Suwannee Sulphur and White Sulphur Springs. The organic matter occurring in the other springs is of small amounts and was not separately determined. Analyses of the water of these springs were given in Bulletin No. I, pp. 72-75, 1908.

51