CONTENTS

 Page
Abstract .. .... ... -- ....... -- ..........-.. ----............----- --- 1
Introduction _--- --- --- -----_---. --------------- 2
 Purpose and scope --..---.-.--- --.----.. ----.---......-- -- 2
 Previous work ---- ---- ------- ---- 3
 Description of the area -...--.--.--.....------.--.... --- ----.---. 4
 Rainfall -_..............-....--_...-_ _.... .......----- ----.. 6
 Temperature ..------...--..- ...---............-_.---..-----. -- 8
 Well-numbering system ...----............---.......---------...--- 8
Geology ............-. ..-_ ---......- ............ ..... 9
 General statement _--- --------------- 9
 Collection of data .--......----- ---......- --- --....... -.--- 9
 Stratigraphy _......... ........------------.--- 11
 Aquifers --------------.----------- --------------- --- --- 11
 Sand-and-gravel aquifer ---......--.-- --------------- -------------. --- 11
 Floridan aquifer _..-- -.... -_ -.. .....--- --.- ----.- 16
 Aquicludes ----_- ......... ~____--..- .----- 18
 Aquicludes within the sand-and-gravel aquifer ----- ---- 18
 Aquicludes below the sand-and-gravel aquifer -- 20
 Aquicludes within the Floridan aquifer __ -_----- 21
 Aquiclude below the Floridan aquifer --------- -------- 21
 Regional dip __- __ -__------ 21
 Relation of geology to ground water -----..----.. ------. ---------- ---- 23
 Movement of water -..............----.-- .------..----- ---- ----- 23
 Relation of geology to quality of water ------23
 Zones of fresh and salty water ---------------- 23
 Mineralization and hardness of ground water ------- 24
 Relation of quality of water to geologic history of the Gulf Coast -- 24
Surface water ..--..-----...... --------------...................----- 25
 Collection of data ___-- 27
 Flow-duration curves ------ -_29
 Perdido River basin ------_______----- 30
 Occurrence of water ------... ------.--- ---- --- 30
 Mineral content ...-----... --. ..........----- -- ----.....- 39
 Escambia River basin -. ..--------. ...--..-.....--- -.- 39
 Occurrence of water --------------__--- --- ---- 39
 Mineral content ....------.__ ...--.--- --..---.---------- 47
 Blackwater River basin ...------...---- ----..---...----..--- 49
 Occurrence of water .....---------------.--------- ----------. -- 49
 Mineral content --------- --- ----------- 55
 Yellow River basin _-----------------------55
 Occurrence of water ---- -- ------------ 55
 Mineral content --- ------- -------.----------- 55
 Ground water -------- _-- --- -- --- -------- 56
 Principles of occurrence ___ ----_--- 56
 Hydrologic properties of the aquifers -- -56
 Sand-and-gravel aquifer -----------57