The Potential For Wave Disturbance in Shallow Florida Lakes

Bachmann. R. W., M. V. Hoyerand D. E. CanfieldJr. 2000. The potential for wave disturbance in.hallow Floridalakes. Lake and Reserv. Manage. 16(4):281-291. We applied wave theory to calculate the extent and frequency that we would expectwav~vensurface water movements to disturb the sediments in.36 Floridalakes coveringa broad range ofsurface areas and mean depths. The calculated per cent ofthe lakebed subject to wave disturbance at one time oranother ranged from 6 to 100% and the per cent of the time 50% of the lakebed was disturbed ranged from 0 to 65%. The large Florida lakes. Apopka, Okeechobee, and Istokpoga showed high levels of calculated wave disturbance, which was consistent with the conclusions ofprevious investigations. Historic water level fluctuations in LakeApopkawere calculatedto have IJIajor effects on wave disturbance in that lake. The dynamic ratio (the square root oflake surface area in sqJJare kilometeR divided by the mean depth in meteR) was significantly related to various measures ofwave disturbance in oursample lakes. For lakes with ratio values above about 0.8 the entire lakebed was subject to wave disturbance at least some of the time. The dynamic ratio was also related to lake water quality. We found that increases in the dynamic ratio were significantly related to decreases in water quality as measured by total phosphorus,total nitrogen. chlorophyll, and Secchi disk depth. Calculations of wind disturbance by waves need to be modified in lakes with extensive beds of macrophytes, where water levels change and in periods where climatic fluctuations result in changes in wind regimes.