Specifications

Section 2 Existing Conditions/Affected Environment
EAA Storage Reservoirs Revised Draft PIR and EIS February 2006
2-37
the wet season, the beginning of winter, lake levels are higher to store water for
the upcoming spring dry season. The general plan of operation for Lake
Okeechobee is based on the following: 1) flood protection from lake waters and
water driven by hurricane winds on lands adjacent to the lake; 2) maintenance
of an eight-foot navigation channel across Lake Okeechobee, as part of the
Okeechobee Waterway; and, 3) storage of water to supply needs of the Lake
Okeechobee service area.
Flood control improvements around Lake Okeechobee consist of a system of
approximately 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 to the St. Lucie Canal and the Caloosahatchee River. The
design discharge of Moore Haven Spillway to the Caloosahatchee River is
9,300 cubic feet per second (cfs) [260 cubic meters (m3)/second (sec)]; that of St.
Lucie spillway is about 16,000 cfs (450 m3/sec). Following removal of local
runoff from the agricultural areas south of the lake, an additional regulatory
capability of several thousand cfs is available through the Miami, North New
River, Hillsboro, and West Palm Beach Canals by pumping into the three WCAs.
The EAA is located south of Lake Okeechobee within a belt of highly organic
hydric soils originally deposited by the historic Everglades wetland called the
“River-of-Grass.” The organic soils have served as a fertile agricultural area
since they were initially drained. Over-drainage and environmental impacts
eventually led to the completion of the C&SF Project. The C&SF Project’s
intention was to provide water storage in the WCAs and to better control water
levels in the Everglades for multiple purposes. As a result, the EAA contains an
elaborate canal system. The construction of canals, levees, and roads has
eliminated the historical freshwater sheet flow and resulted in changes in the
timing and quantity of flow within the system that have influenced water
quality conditions and impacted the downstream EPA.
The revised water management system allowed extensive agricultural
development in the EAA. However, environmental effects continued to be
observed in the downstream areas of the remaining Everglades ecosystem.
Increased loading of phosphorus from the EAA was found to be causing
unacceptable ecological changes to the WCAs and the ENP, which comprise the
EPA. The Everglade Forever Act required that all waters discharged to the EPA
meet applicable water quality standards. Phase I water quality measures
included design and construction of a number of STAs by SFWMD. These STAs
were intended to provide an interim reduction in the observed phosphorus loads.
In addition, a broad suite of agricultural best management practices (BMPs)
were implemented to further lower phosphorus discharges to the EPA. Based on
a phosphorus water quality criterion of 10 µg/L, additional activities were
determined to be necessary to ensure eventual compliance within the EPA. A