Lot of good answers here. Thanks. The ravines are now what they call pocket parks in neighborhoods where there was a lot of action on July 20, 1864. These could only be parks because of small branches which made the ravines in the first place. Probably about on the average 20-30 feet deep. Ravines about 1-2 blocks long and maybe 1 block wide. Just an estimate. Not really kept up, mostly wooded. fairly junky with beer cans and bottle caps where teens from the neighborhoods sneak down to drink and or/camp.
I probably need to hunt these harder than the regular city controlled larger parks which have been well hunted in the 70's and 80's which around Atlanta was the golden age of detecting.
I can see no reason why like gold, lead CW bullets would not wash down to the lower parts of a stream. Same physics apply I am guessing.