MEAN TOTAL WET 

 SEASON RAINFALL 



MEAN TOTAL ORY 

 SEASON RAINFALL 



Key Wesi^i^"^* 



^° 



MEAN ANNUAL RAINFALL 



10 20 30 

 I 1 . P 



MILES 



CONTOURS IMINCHES 



CD35 



Figure 11. Annual mean, total 



wet season, and total 

 dry season rainfall 

 patterns in the study 

 area (adapted from 

 Thomas 1974, MacVicar 

 1981). 



greater than or equal to .0254 cm 

 (0.01 in), for first order stations, 

 and .254 cm (0.10 in), for second- 

 order stations, within or adjacent 

 to the Everglades/Bay/ Keys basin. 

 The distribution of rainfall fre- 

 quency displays a fairly uniform 

 pattern both monthly and seasonally. 

 The lower east coast exhibits a 



greater number of high rainfall days 

 over the summer/wet season than 

 either the Keys or the southwest 

 coast. The mean annual rainfall 

 amounts, and number of days with 

 rainfall greater than or equal to 

 1.27 and 2.54 cm (0.5 and 1.0 in) 

 for the climatic divisions covering 

 the Everglades/Bay/Keys basin also 

 support the trends mentioned above. 



Comparing the rainfall size 

 classes presented for these events 

 yields a ratio of 7:5:2:1; that is, 

 there are roughly 7 times more days 

 recording rainfall greater than or 

 equal to .0254 cm (0.01 in) than 

 .254 cm (1.0 in). Also, the major- 

 ity of the rainfall events (75%) 

 in the basin contribute less than 

 1 .27 cm (0.50 in) . 



The SFWMD has recently com- 

 pleted the first phase of a project 

 which provides an important addition 

 to the rainfall data base. MacVicar 

 (1981) has produced a series of 

 rainfall-frequency maps summarizing 

 the predicted maximum precipitation 

 for durations ranging from one to 

 five days, and wet, dry, and annual 

 series for 1, 3, 5, 10, 25, 50, and 

 100 year return periods. Figure 12 

 presents his results for average 

 annual maximum for 1 day rainfall. 

 These rainfall-frequency maps cover 

 the entire south Florida region, 

 considering data from all rainfall 

 gages with at least 20 years of 

 daily records available. The Fla- 

 mingo Ranger Station at the south- 

 west corner of the mainland, near 

 Cape Sable, was omitted from con- 

 sideration even though more than 

 20 years of records exist (Thomas 

 1974). This omission seriously 



hampers the contours' accuracy in 

 much of the southwestern mainland 

 area of the Everglades/Bay/Keys 

 basin. This should be kept in mind 

 when comparing mean annual and 

 seasonal contours between Thomas 

 (1970, 1974) and MacVicar (1981). 



29 



