peaks: one in March and another of equal 

 tnaqnitude in July. The Florida rainfall 

 peak in March is not as great as that of 

 Georgia, but the primary difference is the 

 much larger, sustained rainfall peak in 

 summer and early fall in Florida. In both 

 areas, there are drought periods during 

 mid to late fall. Spectral analysis of 

 long-term trends (Figure 10) indicate 

 that, while rainfall is highly variable, 

 there are certain long-term trends. 

 Florida (Apal achicola) rainfall has 

 RO-month ('i."'-yr) cycles in peak reoccur- 

 rence, while Georgia rainfall has a 

 slightly different spectrum. 



2.^.3. 



Wind 



Wind direction is predominantly from 

 the southeast during the spring 

 (March-May) and southwest to west during 

 the summer (June-August). Winds come from 

 the north or northeast during the rest of 

 the year. However, analysis of long-term 

 wind data indicates that there is wide 

 variability of wind velocity and direction 

 over the Apalachicola watershed at any 

 given time. Tn the shallow estuary, winds 

 can cause rapid changes in the normal 

 tidal current patterns. Southerly winds 

 tend to augment astronomical tides and 



UJ 



o 



< 560  



a: 

 u 

 > 



< 



CO (5 400- 



"I 



o 



2 240- 



z 

 o 



«> 



80- 



RIVER FLOW 



1920 



I 



1925 



1930 



I I 



1935 1940 



-400 



LJ 

 < 



ir 



LlI 



> 



< 



300 CP 



■200 



-100 



T 



T 



T 



1945 1950 1955 I960 1965 



— 1 



1970 



— 1 



1975 



O) 



> o 

 o 





liJ 

 O 

 < 



UJ 



o 



o 



CD 



24 - 



16- 



6 MONTH - 

 36 MONTH 



RAINFALL 



1920 



—I 



1925 



-| 1 \ 



1930 1935 1940 



-I \ 



1945 1950 



1955 



-1 1 



i960 1965 



"1 1 



1970 1975 



YEARS 



UJ 

 C3 

 < 



cr 



UJ 

 iS) 



z 



> 



o 



o 



CO 

 fO 



Figure 10. Six-month and 36-month moving averages of Apalachicola River flow 

 (cfs; 1920-1977) and Apalachicola rainfall (1937-1977). Data are taken from Meeter 

 et al. (1979). 



12 



