Alafia River Minimum Flows and Levels - Southwest Florida Water ...

Julian day 301 (October 28) to Julian day 109 (April 19) of the following calendar
year. Using these definitions: Blocks 1, 2, and 3 are 65, 176 and 124 days in
length, respectively (Table 2-6).
The three flow blocks were utilized for development of minimum flows for the
Alafia River and are evident in a hydrograph of median daily flows for the Lithia
gage site (Figure 2-16). Lowest flows, which are typically confined to the river
channel, occur during Block 1. Highest flows, which are often sufficient for
inundating the river floodplain, occur during Block 3, although high flows may
also occur during Block 2. Medium flows occur during Block 2.
Table 2-5. Beginning Julian days for the Wet and Dry periods (Blocks 1 and 3) and ending
date for the Wet period at five different gage stations in the SWFWMD.
Begin Dry
(Block 1)
Begin Wet
(Block 3)
End Wet
(Block 3)
Alafia at Lithia 106 175 296
Hillsborough at
112 176 296
Zephyrhills
Myakka at Sarasota 115 181 306
Peace at Arcadia 110 174 299
Withlacoochee at Croom 130 208 306
Mean w/o
110 176 300
Withlacoochee
Mean with
Withlacoochee
114 183 301
Table 2-6. Beginning and ending calendar dates for annual flow Blocks 1, 2, and 3 for the
Alafia, Hillsborough, Myakka and Peace Rivers for non-leap years. Calendar dates apply
for both non-leap years and leap years.
Start Date (Julian Day) End Date (Julian Day) Number of Days
Block 1 April 20 (110) June 24 (175) 65
Block 2 October 28 (301) April 19 (109) 176
Block 3 June 25 (176) October 27 (300) 124
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