ANALYSIS OF WATER-LEVEL--LAKE JACKSON


 SUMMARY

 The present high level of Lake Jackson is due to the occurrence
 of an unusual number of successive years of greater-than-average
 rainfall. Total rainfall at Tallahassee during the 3-year period
 1963-65 exceeded that for any 3-year period since at least 1885.
 By way of contrast, the drought at Tallahassee during 1954-56 was
 the most extreme that has occurred since at least 1885. Oddly
 enough, this severe drought occurred within the decade (1956-65)
 having the highest average rainfall since at least 1885.
 Rainfall on the lake and surface-water inflow to the lake during
 and immediately after storms basically are the only factors causing
 the lake level to rise, rainfall being the predominant factor.
 Ground-water inflow apparently contributes appreciable water to
 the lake during years of greater-than-average rainfall. Ground-
 water inflow contributes to the over-all rise of the lake by retarding
 the lake-level decline due to evaporation and ground-water outflow
 during the interval between storms.
 The level of Lake Jackson can be stabilized within reasonable
 limits. However, facilities for doing so must be designed to remove
 large amounts of water from the lake during years of unusually
'great rainfall and to return large amounts of water to the lake
during most years of less-than-average rainfall.


 REFERENCES

 Kohler, M. A.
 1959 (and Nordenson, T. J. and Baker, D. R.) Evaporation maps for
 the United States: U. S. Weather Bureau Tech. Paper No. 37.
 Sellards, E. H.
 1914 Some Florida lakes and lake basins in Sixth Annual Report:
 Florida Geological Survey.