WATER RESOURCES OF ORANGE COUNTY 135
to the entire thickness of the aquifer. The transmissibility and storage coefficients obtained by the leaky aquifer method apply to the main producing zone, and the leakage coefficient applies to the less permeable overlying beds.
Test 1 was made in the eastern part of the City of Orlando on February 17, 1961, with the cooperation of the Orlando Department of Water and Sewers. A 12-inch drainage well (831-122-4) on Lake Davis was pumped for 11 hours at 1,100 gpm and the resulting decline in water levels (drawdown) was recorded in four nearby wells. The water was discharged into Lake Davis and did not appreciably change the surface hydrologic conditions. Irregular discharge from supply wells and irregular recharge through other drainage wells in the city made it difficult to delineate the effects from the drawdown curves caused by pumping the test well. This may account in part for the wide range in the values of the coefficients in Test 1 (table 14). Some of the variation in coefficients may be caused by different well depths and casing depths; but the principal cause of the wide value range in coefficients is probably the non-homogeneous and anisotropic character of the limestone aquifer.
Test 2 was made in October 15-16, 1962 at Long Lake, about 6 miles northwest of Orlando. A 20-inch drainage well (836-128-1) was pumped for 24 hours at 1,535 gpm and drawdown was recorded in two nearby wells. The values of the aquifer coefficients as determined from the more distant observation well (471 feet) were in reasonable agreement with the values determined from other tests in the upper zone of the aquifer; but the transmissibility value from the well near to the pumping well (63 feet) was much lower. The cause of the difference is problematical, but it may be due partly to a direct underground connection between the pumped well and the nearer observation well and partly to the large quantity of sand that fills the solution channels in some parts of the aquifer. The direct connection between the wells was discovered when the turbine pump column was installed in the 20-inch well. As each section was lowered into the well, it caused a surge of about 2 inches in the observation well. The sand in the aquifer was discovered during the drilling of the more distant observation well. The sand probably restricted the flow of water from some directions and the channelization enabled a higher than normal percentage of the water to flow from the vicinity of the nearby observation well. This probably caused an abnormal drawdown pattern in the nearby observation well. As in test 1, the non-homogeneous and