Average annual precipitation -1,025 to 1,400 mm. Maximum precipitation is in summer. Rainfall, perennial streams, and ground water provide an abundance of water. Water for domestic, municipal, and industrial uses is obtained mainly from wells. Many of the soils require artificial drainage before they can be used for crops, and some of the sandy soils need irrigation during droughts.
Soils having restricted drainage are dominant throughout the area.
Most extensive are Aquults. They have a thermic temperature regime and an aquic moisture regime. They are deep and medium textured to fine textured. Histosols occupy fairly large areas, especially in the Okefenokee Swamp of Georgia and Florida. Loblolly pine and upland oaks are dominant on the uplands, and water tupelo, swamp blackgum, sweetgum, and oaks are dominant on the bottom lands.