REPORT OF INVESTIGATIONS NO, 42


5 10 15 20 25 30 35


 Annual runoff, in inches
 Figure 47. Relation of effective annual rainfall and annual runoff,
 Withlacoochee River at Trilby, 1931-61.



 The runoff from the upper Palatakaha Creek basin has been
measured since 1945 (stations 11 and 12 in table 1). The water-loss
curve for the upper Palatlakaha Creek basin is shown in figure 48.
Runoff was adjusted for annual changes in storage in the many
lakes and swamps in the basin. No allowance was made for change
in underground storage or for seepage into or out of the basin.
 The water-loss curves shown in figures 46 and 48 indicate that,
for a year in which rainfall was 32 inches or less, the natural losses
would nearly equal the rainfall and little or no runoff would occur
from either the Withlacoochee River or the Palatlakaha Creek
basins in the Green Swamp area.
 As shown in figure 48, the potential natural water loss for the
upper Palatlakaha Creek basin is 48 inches which is the same as the
annual water loss shown for 72F. in figure 7. Figure 49 shows the
 t


80



70 ---- --------------------- ---- --__----- -3------



60



50

 -3--
 */"


 40 *
 Note Total runoff adjusted
 to include diversions
 above station into
 Hillsborough River
 30



 30 ----------- --- ----


0