76 FLORIDA GEOLOGICAL SURVEY-THIRD ANNUAL REPORT.
It is doubtless true that some of the lakes, especially the smaller ones, could be drained by surface ditching. Any attempt at drainage should be preceded, however, by the preparation of a carefully made topographic map of the region, or at least sufficient exact leveling should be made to determine definitely the relation of the lake basin to the proposed outlet, and to the intervening country.
While some of these lakes can be drained by bored 'Wells it is not to be assumed that all can be so drained. As has been shown some of these lake basins, especially the larger ones, have been'low ered by solution practically to the permanent underground water level. Before attempting drainage by wells definite data should be obtained as to the relation between the level of the lake basin and the underground water level of that locality. This information can often be obtained by running a line of levels f rom the lake to at near by deep well and comparing the level of water in the lake with the level at which the water stands in the well. If necessary, test wells may be drilled before undertaking large wells. Such lakes as have been lowered by natural drainage actually to the underground water level can of course be lowered no further by wells