Specifications

Section 2 Existing Conditions/Affected Environment
EAA Storage Reservoirs Revised Draft PIR and EIS February 2006
2-7
southeastern Alabama, southern Georgia, and southwestern South Carolina.
This aquifer is composed of a thick sequence of limestone layers and is divided
into Upper Floridan and Lower Floridan, by a less permeable middle confining
unit of carbonates. In the EAA, the water of the Floridan aquifer is rather salty,
particularly in the Lower Floridan (Sprinkle, 1989).
2.5 FLOOD PROTECTION LEVEL OF SERVICE
The EAA depends on the flood storage capacity of the WCAs, and to a lesser
extent, on Lake Okeechobee, as a means to remove water from the basin. In the
case of extreme events such as a hurricane, flood storage in Lake Okeechobee
becomes more important. Flood control works on Lake Okeechobee consist of a
system of about 1,000 miles (1,600 km) of encircling levees, designed to
withstand a severe combination of flood stage and hurricane occurrence, plus the
regulatory outlets of St. Lucie Canal and the Caloosahatchee River.
2.6 CLIMATE
2.6.1 General Climate
The climate of the Everglades is characterized by two seasons: the dry and wet
seasons. The dry season extends from November to April. The winter weather
cold air fronts that often pass through the region weekly bring cool, but rarely
freezing, temperatures. At this time of the year, there is low intensity, moderate
rainfall with about 25% of the area’s annual rainfall of 53 inches occurring
during the dry season.
During the wet season, the region experiences daily thunderstorms, intense
solar radiation, and high humidity. Seventy-five percent of the rain occurs in
this wet season and can include a variable number of extreme rainfall conditions
such as hurricanes and tropical storms. The wet season has a bimodal rainfall
pattern with one peak between May and June and the second peak between
September and October. Every 10 years or so, the region alternates between
flood and drought conditions. Annual rainfall, while averaging 53 inches, has
ranged from a low of 36 inches to a high of 100 inches.
Mean annual temperature for the South Florida ecosystem ranges from 72°F
(22°C) in the northern Everglades to 76°F (24°C) in the south (Thomas, 1974).
Mean monthly temperatures range from a low of 63°F (17°C) in January to a
high of 85°F (29°C) in August (Thomas, 1974). Infrequently, freezing
temperatures and frost occur when arctic air masses follow winter cold fronts
into the area.