REPORT OF INVESTIGATIONS No. 40


in the basin drain very hilly country. The hills are from 100 to 150 feet
above the stream valleys. The fall of the Perdido River streambed from
the Alabama-Florida State line to Muscogee is 150 feet for a channel
length of about 40 miles. The fall from Muscogee to Perdido Bay is 15
feet for a channel length of about 20 miles (taken from U.S.G.S. topo-
graphic maps).
 Tidal fluctuations occur in the lower reach of the river. During
periods of low flow, tidal effects extend about 15 miles upstream from
Perdido Bay nearly to Muscogee. Tidal effect will extend the greatest
distance upstream during periods when the river is low and the tides
are at seasonal highs. The salt front, however, does not extend as far
upstream as the tidal effect.
 The downstream, 10-mile reach of the main channel is generally
more than 10 feet deep, with holes extending to 45-feet depths. A depth-
profile graph of the lower 10 miles of the river is given in figure 19.






 14 mli
 13.m. Omi. (Mouth) ay









 S--250--CSlitd. cu.lul; i p1 p. .14.
 Iemi. mi.







 9 --. 4- M. - --lo


 -W e r
 5. b.9n~


Figure 19. Channel-bottom profile of lower Perdido River.