74 FLORIDA GEOLOGICAL SURVEY-THIRD ANNUAL REPORT.
however, that of spouting is certainly the most striking and remarkable.
In considering the use of wells for drainage purposes the relation of the lake basin to the underground water level should first be definitely determined. The effectiveness of the well is reduced as the water level is approached, and it is of course obvious that the water in the lake can in no case be carried below the underground water level. Many of the larger lake basins are known to lie very close to the water level. If the lake basin lies as low as the permanent water level it is obvious that the water in the lake can not be drained by wells, moreover since the effectivness of the well is affected by the near approach to the water level, it is hardly practicable to reduce the water in the lake quite to the permanent underground water level. It must also be borne in mind that while the underground water is a permanent supply the water level or water line is not stationary, but varies with the seasons. The amount of variation for the locality concerned should be determined.
The fact that a lake basin stands somewhat above the water line at the close of a long dry season is not proof that it will be found to stand above the water line after a season of heavy, rainfall. In some sections of the state the range of variation of the water line has been found to be as much as ten feet, and may in some instances exceed that amount.
The relation between the level of the lake basin and the underground water has been determined for a few of the lakes. Measurements of Alachua Lake were made in 1907 and again in 1909. When measured in October, 1907, the water level in Alachua Lake was found to be 2.01 feet above the level of the underground water of the Vicksburg Limestone formation as determined from the Gainesville City well.* When measured in. November, I9O9. the water in the sink stood approximately 1.4 feet above the water level in the limestone as indicated by the city well. At the time these measurements were made the lake was at a low water stage. The underground water level was likewise at a low stage. From these measurements it appears that Alachua Lake during the dry seasons at least is lowered by natural drainage through the sink to or practically to the underground water level. During the rainy season the water in the lake doubtless rises above this level, alLhough it must be borne in mind that the water line also rises during the rainy season. It is evident, therefore, that the difference between the water level in the lake and the underground water line is great*For a record of this well, see Bull. No. I, pp. 30 and 88-89, i908.