Fourteen interconnected lakes in and around the city of Winter Haven, Polk County, Fla., form the Winter Haven Chain of Lakes. Levels of the lakes during the spring of 1976 were at a record low stage for the 31 years of record. During 1960-76, rainfall had been below average for all but 2 years, and departure from average rainfall totaled 72.34 inches. Fluctuations in stage of Lake Howard, representative of the chain, and of Lake Otis, the nearest isolated lake that has a reasonably long record of stage , were compared with other hydrologic variables. Analyses of lake stage and rainfall records indicate that deficient rainfall has been the key factor in the decline of lake levels in the area. Manipulation of lake levels, pumpage from the lakes and underlying aquifer, and urbanization of the watershed probably have affected the lakes as well, but records are not available to determine the significance of their effects. The surficial aquifer drains to the lakes. Water level in the underlying Floridan aquifer is everywhere lower than in any of the lakes, thus water moves from the lakes and surficial aquifer through the confining clay layer to the Floridan aquifer.
